Garrett GT4088R with fitment issues
#1
Garrett GT4088R with fitment issues
Gentlemen, I need some help. Here's the deal; I am tackling some projects right now and have decided that I have to get a turbo blanket onto my setup. I found my wheel speed sensor wiring for example burned to glass almost because my the turbine housing is within a couple mm's of the frame.
My solution was to shave a touch off the manifold flange and maybe the turbo flange as well to give me some more clearance on that side. Problem is, if I do that it will bring the turbo in and most probably make the compressor housing hit the LIM.
So, I'm in a classic "damned if you do, damned if you don't" scenario and I don't know what to do exactly.
Here's my options as I see it:
1: Remove turbo and manifold and beat the strut tower in slightly to give me the requisite space for the blanket to fit around the turbine housing. The fear is doing damage to the strut tower which would weaken it and compromise the structural integrity of the strut tower.
2: Shave a few mm's off the manifold flange and maybe turbo flange, and then sand down or machine material off the LIM and hope you can remove enough material without breaking through into the intake runner.
3: Replace turbine housing with a .85 A/R housing which I've confirmed with ATP Turbo is about 2mm shorter from flange to the apex of the turbine housing, than my .95 A/R turbine housing currently on the car. This makes the most sense but is most expensive at $300-$400 for the housing.
4: Ditch the turbo, try to sell it and buy a smaller turbo better suited for the setup for equal or lesser money. This would most probably take time and my car is down right now. I don't want it to sit too long for obvious reasons.
Your feedback would be appreciated fellas.
Nick
My solution was to shave a touch off the manifold flange and maybe the turbo flange as well to give me some more clearance on that side. Problem is, if I do that it will bring the turbo in and most probably make the compressor housing hit the LIM.
So, I'm in a classic "damned if you do, damned if you don't" scenario and I don't know what to do exactly.
Here's my options as I see it:
1: Remove turbo and manifold and beat the strut tower in slightly to give me the requisite space for the blanket to fit around the turbine housing. The fear is doing damage to the strut tower which would weaken it and compromise the structural integrity of the strut tower.
2: Shave a few mm's off the manifold flange and maybe turbo flange, and then sand down or machine material off the LIM and hope you can remove enough material without breaking through into the intake runner.
3: Replace turbine housing with a .85 A/R housing which I've confirmed with ATP Turbo is about 2mm shorter from flange to the apex of the turbine housing, than my .95 A/R turbine housing currently on the car. This makes the most sense but is most expensive at $300-$400 for the housing.
4: Ditch the turbo, try to sell it and buy a smaller turbo better suited for the setup for equal or lesser money. This would most probably take time and my car is down right now. I don't want it to sit too long for obvious reasons.
Your feedback would be appreciated fellas.
Nick
#2
Rotary Enthusiast
iTrader: (1)
MJ said it best, just beat it.
You can also use a stainless steel heat shield aka pot.
Inconel heat shield, also costly.
But both are way thinner.
I don't have pictures but I also run a GT40 w/ a 1.06 hotside. XS/HKS manifold. Didn't have to beat the strut tower, but the areas around there. Ran a blanket for years, switched to inconel, loads of rooom.
You can also use a stainless steel heat shield aka pot.
Inconel heat shield, also costly.
But both are way thinner.
I don't have pictures but I also run a GT40 w/ a 1.06 hotside. XS/HKS manifold. Didn't have to beat the strut tower, but the areas around there. Ran a blanket for years, switched to inconel, loads of rooom.
#3
silentblu, thanks for your feedback dude. My manifold is from A-Spec and I believe they basically didn't want to re-engineer their GT35 manifold or something and made this work. The position of the turbo is far from ideal. Check out these pictures:
Notice how the compressor housing is nearly touching the LIM in two spots.
And here, you can see the turbine housing is virtually touching the strut tower. If I pull a Michael, I'll have to beat in the corner of the strut tower possibly weakening it. That's my dilemma.
I thought about running this inconel shield, but at $520 and no guarantee it would actually fit, I think I'm not going to fuss with it...
Im leaning towards buying the .85 turbine housing, seeing where I'm at and then resorting to violence if necessary. If I gain a little bit of clearance from the smaller housing, perhaps I'll only have to dent the strut tower, as opposed to beating the hell out of it.
Nick
Notice how the compressor housing is nearly touching the LIM in two spots.
And here, you can see the turbine housing is virtually touching the strut tower. If I pull a Michael, I'll have to beat in the corner of the strut tower possibly weakening it. That's my dilemma.
I thought about running this inconel shield, but at $520 and no guarantee it would actually fit, I think I'm not going to fuss with it...
Im leaning towards buying the .85 turbine housing, seeing where I'm at and then resorting to violence if necessary. If I gain a little bit of clearance from the smaller housing, perhaps I'll only have to dent the strut tower, as opposed to beating the hell out of it.
Nick
Last edited by Brilliant7-LFC; 07-13-17 at 09:22 PM.
#5
That would definitely represent the easiest route, no question. However, ceramic coating has it's limitations. I know turbo blankets are so effective at mitigating heat from the turbine housing that you can actually rest your hand on the blanket while doing a pull on the dyno and not burn your hand. I wouldn't dream of doing that with a ceramic coated turbine housing.
My goal is to reduce the temperatures in that area to the point where I don't need to treat the AC lines in that area, or the coolant hoses. With Titanium heat wrap and the Titanium turbo blanket, I think I can achieve that goal.
Nick
My goal is to reduce the temperatures in that area to the point where I don't need to treat the AC lines in that area, or the coolant hoses. With Titanium heat wrap and the Titanium turbo blanket, I think I can achieve that goal.
Nick
#6
Rotary Enthusiast
iTrader: (1)
From your pictures it looks very similar to my setup location wise, I sit farther back towards the firewall, my compressor is approximately where your exhaust housing would be.
I was able to fit various turbo blankets, while the engine/turbo was in the car. The square-ish PTP looking ones, and then the rounder titanium looking ones. Both were pretty much sandwiched to the frame, and I consider all turbo blankets single use, as in you install it once, and if you take it off its done, all the fiberglass/material flakes off/crispy. It did reduce temps but I would not rest my hand during a pull on them.
I would recommend you contact Turblown, they do Inconel wraps and are slightly cheaper then the one you quoted ~$450 (?), and will have you send in your exhaust housing to get fit. They will likely be able to provide you more details on thickness and fitment. I had mine done locally in CA.
Is the exhaust housing touching the frame in the last picture? or is that just from the angle?
I was able to fit various turbo blankets, while the engine/turbo was in the car. The square-ish PTP looking ones, and then the rounder titanium looking ones. Both were pretty much sandwiched to the frame, and I consider all turbo blankets single use, as in you install it once, and if you take it off its done, all the fiberglass/material flakes off/crispy. It did reduce temps but I would not rest my hand during a pull on them.
I would recommend you contact Turblown, they do Inconel wraps and are slightly cheaper then the one you quoted ~$450 (?), and will have you send in your exhaust housing to get fit. They will likely be able to provide you more details on thickness and fitment. I had mine done locally in CA.
Is the exhaust housing touching the frame in the last picture? or is that just from the angle?
#7
From your pictures it looks very similar to my setup location wise, I sit farther back towards the firewall, my compressor is approximately where your exhaust housing would be.
I was able to fit various turbo blankets, while the engine/turbo was in the car. The square-ish PTP looking ones, and then the rounder titanium looking ones. Both were pretty much sandwiched to the frame, and I consider all turbo blankets single use, as in you install it once, and if you take it off its done, all the fiberglass/material flakes off/crispy. It did reduce temps but I would not rest my hand during a pull on them.
I would recommend you contact Turblown, they do Inconel wraps and are slightly cheaper then the one you quoted ~$450 (?), and will have you send in your exhaust housing to get fit. They will likely be able to provide you more details on thickness and fitment. I had mine done locally in CA.
Is the exhaust housing touching the frame in the last picture? or is that just from the angle?
I was able to fit various turbo blankets, while the engine/turbo was in the car. The square-ish PTP looking ones, and then the rounder titanium looking ones. Both were pretty much sandwiched to the frame, and I consider all turbo blankets single use, as in you install it once, and if you take it off its done, all the fiberglass/material flakes off/crispy. It did reduce temps but I would not rest my hand during a pull on them.
I would recommend you contact Turblown, they do Inconel wraps and are slightly cheaper then the one you quoted ~$450 (?), and will have you send in your exhaust housing to get fit. They will likely be able to provide you more details on thickness and fitment. I had mine done locally in CA.
Is the exhaust housing touching the frame in the last picture? or is that just from the angle?
My only option that doesn't include
modifying the strut tower is to shave the manifold flange to bring it further in which may then introduce the compressor housing to the LIM. There's only a few millimeters between the compressor and LIM as is, so if I take material off the flange and pull the turbo in towards the engine, I'll definitely have to start shaving the LIM to make it work.
And no, that last picture looks like it is; EXTREMELY close. There's about 1mm gap between the turbine housing and strut tower. The "frame rail" portion of the body has a little bigger of a gap.
Nick
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#10
Rotary Enthusiast
iTrader: (1)
I spoke with Elliot at Turblown and he quoted me $550 to custom make an inconel shield. At this stage I'm basically between two options: either hammer the strut tower and be done, or spend $300 on a .85 a/r turbine housing which is smaller and hope that works, and maybe still have to bang the strut tower.
My only option that doesn't include
modifying the strut tower is to shave the manifold flange to bring it further in which may then introduce the compressor housing to the LIM. There's only a few millimeters between the compressor and LIM as is, so if I take material off the flange and pull the turbo in towards the engine, I'll definitely have to start shaving the LIM to make it work.
And no, that last picture looks like it is; EXTREMELY close. There's about 1mm gap between the turbine housing and strut tower. The "frame rail" portion of the body has a little bigger of a gap.
Nick
My only option that doesn't include
modifying the strut tower is to shave the manifold flange to bring it further in which may then introduce the compressor housing to the LIM. There's only a few millimeters between the compressor and LIM as is, so if I take material off the flange and pull the turbo in towards the engine, I'll definitely have to start shaving the LIM to make it work.
And no, that last picture looks like it is; EXTREMELY close. There's about 1mm gap between the turbine housing and strut tower. The "frame rail" portion of the body has a little bigger of a gap.
Nick
For proper heat management, you need that air gap to act as an insulator, direct contact for all heat management products have a much lower rated temperature rating, and a smashed turbo blanket will likely get extra crispy extra fast.
Did Elliot say anything on the thickness or the likely outcome with going inconel?
Have you thought or are you prepared with the other aspects of going with a smaller AR exhaust housing? Need for tune, powerband of the car, future aspirations? i.e. more boost? etc.
Think about it, Inconel $550 vs. new housing ($300), turbo blanket ($100) and a tune (???). My math puts the inconel as winning.
OR leave the housing alone, and shield everything else. LIM, AC lines, box in your air filter, wrap your downpipe.
#11
Original Gangster/Rotary!
iTrader: (213)
From talking to Nick extensively on this subject, one thing he really liked about the blankets is that you can rest your hand on it and not get burned. I've been using inconel on my manifolds and turbine housings for many years now....... and I wouldn't dream of resting my hand on it after use, it would not be fun
Inconel with the air gap is the way to go as it doesn't smother the turbine, but you'd still want to shield all the peripheral parts around it as you still get a degree of radiant heat.
Inconel with the air gap is the way to go as it doesn't smother the turbine, but you'd still want to shield all the peripheral parts around it as you still get a degree of radiant heat.
#12
If it is extremely close, I highly doubt a turbo blanket would fit even with the smaller AR housing. If you have seen how thick an inconel shield is vs. any blanket, you will understand why. The inconel shield itself is also pliable. Not exact figures, but the blanket will be anywhere from 1/8" to 1/4" maybe, and the inconel is a sheet of metal 16/18 gauge in thickness, no more then 1/16".
For proper heat management, you need that air gap to act as an insulator, direct contact for all heat management products have a much lower rated temperature rating, and a smashed turbo blanket will likely get extra crispy extra fast.
Did Elliot say anything on the thickness or the likely outcome with going inconel?
Have you thought or are you prepared with the other aspects of going with a smaller AR exhaust housing? Need for tune, powerband of the car, future aspirations? i.e. more boost? etc.
Think about it, Inconel $550 vs. new housing ($300), turbo blanket ($100) and a tune (???). My math puts the inconel as winning.
OR leave the housing alone, and shield everything else. LIM, AC lines, box in your air filter, wrap your downpipe.
For proper heat management, you need that air gap to act as an insulator, direct contact for all heat management products have a much lower rated temperature rating, and a smashed turbo blanket will likely get extra crispy extra fast.
Did Elliot say anything on the thickness or the likely outcome with going inconel?
Have you thought or are you prepared with the other aspects of going with a smaller AR exhaust housing? Need for tune, powerband of the car, future aspirations? i.e. more boost? etc.
Think about it, Inconel $550 vs. new housing ($300), turbo blanket ($100) and a tune (???). My math puts the inconel as winning.
OR leave the housing alone, and shield everything else. LIM, AC lines, box in your air filter, wrap your downpipe.
The performance changes of going with a .85 housing are something I've considered as well. My turbo as it sits with the .95 housing is pretty laggy. I have a short runner manifold and twin scroll setup, divided T4. Reducing the housing to .85 should "wake up" the turbo a bit. I actually sent a PM to Howard on the subject to get some input on the smaller housing's effect in a mathematical sense, but I haven't heard back.
From talking to Nick extensively on this subject, one thing he really liked about the blankets is that you can rest your hand on it and not get burned. I've been using inconel on my manifolds and turbine housings for many years now....... and I wouldn't dream of resting my hand on it after use, it would not be fun
Inconel with the air gap is the way to go as it doesn't smother the turbine, but you'd still want to shield all the peripheral parts around it as you still get a degree of radiant heat.
Inconel with the air gap is the way to go as it doesn't smother the turbine, but you'd still want to shield all the peripheral parts around it as you still get a degree of radiant heat.
Nick
#13
B O R I C U A
iTrader: (14)
Gentlemen, I need some help. Here's the deal; I am tackling some projects right now and have decided that I have to get a turbo blanket onto my setup. I found my wheel speed sensor wiring for example burned to glass almost because my the turbine housing is within a couple mm's of the frame.
My solution was to shave a touch off the manifold flange and maybe the turbo flange as well to give me some more clearance on that side. Problem is, if I do that it will bring the turbo in and most probably make the compressor housing hit the LIM.
So, I'm in a classic "damned if you do, damned if you don't" scenario and I don't know what to do exactly.
Here's my options as I see it:
1: Remove turbo and manifold and beat the strut tower in slightly to give me the requisite space for the blanket to fit around the turbine housing. The fear is doing damage to the strut tower which would weaken it and compromise the structural integrity of the strut tower.
2: Shave a few mm's off the manifold flange and maybe turbo flange, and then sand down or machine material off the LIM and hope you can remove enough material without breaking through into the intake runner.
3: Replace turbine housing with a .85 A/R housing which I've confirmed with ATP Turbo is about 2mm shorter from flange to the apex of the turbine housing, than my .95 A/R turbine housing currently on the car. This makes the most sense but is most expensive at $300-$400 for the housing.
4: Ditch the turbo, try to sell it and buy a smaller turbo better suited for the setup for equal or lesser money. This would most probably take time and my car is down right now. I don't want it to sit too long for obvious reasons.
Your feedback would be appreciated fellas.
Nick
My solution was to shave a touch off the manifold flange and maybe the turbo flange as well to give me some more clearance on that side. Problem is, if I do that it will bring the turbo in and most probably make the compressor housing hit the LIM.
So, I'm in a classic "damned if you do, damned if you don't" scenario and I don't know what to do exactly.
Here's my options as I see it:
1: Remove turbo and manifold and beat the strut tower in slightly to give me the requisite space for the blanket to fit around the turbine housing. The fear is doing damage to the strut tower which would weaken it and compromise the structural integrity of the strut tower.
2: Shave a few mm's off the manifold flange and maybe turbo flange, and then sand down or machine material off the LIM and hope you can remove enough material without breaking through into the intake runner.
3: Replace turbine housing with a .85 A/R housing which I've confirmed with ATP Turbo is about 2mm shorter from flange to the apex of the turbine housing, than my .95 A/R turbine housing currently on the car. This makes the most sense but is most expensive at $300-$400 for the housing.
4: Ditch the turbo, try to sell it and buy a smaller turbo better suited for the setup for equal or lesser money. This would most probably take time and my car is down right now. I don't want it to sit too long for obvious reasons.
Your feedback would be appreciated fellas.
Nick
I vote for #3 or #4, I had a similar issue, but it was the other way around, the turbo hot side was hitting the intake manifold (more like the intake manifold was in the turbo's way). I ended up making a spacer...
Spend money on something that you could sell in the future, and gain some of your expenses back. In my case, nobody wants a custom adapter, on the other hand, selling a turbine housing will sell fairly easy.
Yes a turbo blanket will shorten the life of your turbine housing, that's a fact that I accept, in order to keep under hood temps "under control".
Try a turbo blanket before doing anything, even with the lack of space between the turbine housing and the strut tower/LIM, you should be able to fit it. A blanket is the cheapest solution, the easiest, and quite frankly, the one that will provide the best results.
#15
I put the question mark because I don't really know. I reached out to Howard Coleman because I know he often times does the math on turbo's and seems to know my turbo well. I spoke with him when I first got the car to discuss some other things and he spoke highly of the GT4088R, so I figured he wouldn't steer me wrong...long story, short -- Howard's exact words were:
"the tail could be wagging the dog here and you will be creating a larger problem.
do not go anywhere near the smaller hotside. it will produce too much exhaust backpressure and eventual detonation.
the proper hotside is the 1.06 but the .95 will work. the cause of your problem is the manifold not the turbo of course. i would not hesitate to "modify" my shock tower/inner fender to fit the turbo but that is just me. engineer first and aesthetics later."
With that sort of advice, I decided against the .85 turbine housing and beat the hell out of my strut tower yesterday. I've cleared enough space now to fit the blanket - I think. We will see in a couple week's time when I get the blanket.
At first, I thought the smaller hotside would be a good idea, in order to reduce my lag somewhat. But, after doing some research and getting that advice from Howard, I've opted to make a couple changes first before considering going that route.
First, I've increased my spring pressure on the gate from 7psi to 14psi. I will also reference boost to the WG from the compressor housing, as that's how the diagram in the TurboSmart manual says to do it. Perhaps with those changes, I'll see a reduction in lag from the turbo.
I'm open to other suggestions as well...
Thanks guys!
Nick
#16
B O R I C U A
iTrader: (14)
The simple answer is: probably not?
I put the question mark because I don't really know. I reached out to Howard Coleman because I know he often times does the math on turbo's and seems to know my turbo well. I spoke with him when I first got the car to discuss some other things and he spoke highly of the GT4088R, so I figured he wouldn't steer me wrong...long story, short -- Howard's exact words were:
"the tail could be wagging the dog here and you will be creating a larger problem.
do not go anywhere near the smaller hotside. it will produce too much exhaust backpressure and eventual detonation.
the proper hotside is the 1.06 but the .95 will work. the cause of your problem is the manifold not the turbo of course. i would not hesitate to "modify" my shock tower/inner fender to fit the turbo but that is just me. engineer first and aesthetics later."
With that sort of advice, I decided against the .85 turbine housing and beat the hell out of my strut tower yesterday. I've cleared enough space now to fit the blanket - I think. We will see in a couple week's time when I get the blanket.
At first, I thought the smaller hotside would be a good idea, in order to reduce my lag somewhat. But, after doing some research and getting that advice from Howard, I've opted to make a couple changes first before considering going that route.
First, I've increased my spring pressure on the gate from 7psi to 14psi. I will also reference boost to the WG from the compressor housing, as that's how the diagram in the TurboSmart manual says to do it. Perhaps with those changes, I'll see a reduction in lag from the turbo.
I'm open to other suggestions as well...
Thanks guys!
Nick
I put the question mark because I don't really know. I reached out to Howard Coleman because I know he often times does the math on turbo's and seems to know my turbo well. I spoke with him when I first got the car to discuss some other things and he spoke highly of the GT4088R, so I figured he wouldn't steer me wrong...long story, short -- Howard's exact words were:
"the tail could be wagging the dog here and you will be creating a larger problem.
do not go anywhere near the smaller hotside. it will produce too much exhaust backpressure and eventual detonation.
the proper hotside is the 1.06 but the .95 will work. the cause of your problem is the manifold not the turbo of course. i would not hesitate to "modify" my shock tower/inner fender to fit the turbo but that is just me. engineer first and aesthetics later."
With that sort of advice, I decided against the .85 turbine housing and beat the hell out of my strut tower yesterday. I've cleared enough space now to fit the blanket - I think. We will see in a couple week's time when I get the blanket.
At first, I thought the smaller hotside would be a good idea, in order to reduce my lag somewhat. But, after doing some research and getting that advice from Howard, I've opted to make a couple changes first before considering going that route.
First, I've increased my spring pressure on the gate from 7psi to 14psi. I will also reference boost to the WG from the compressor housing, as that's how the diagram in the TurboSmart manual says to do it. Perhaps with those changes, I'll see a reduction in lag from the turbo.
I'm open to other suggestions as well...
Thanks guys!
Nick
For what is worth, I run a T4 .84 housing, been doing it for 5 years or so, no issues; however my car was tuned by an experience tuner, AND I run water injection on to of the tune AND I only run 15psi on a T04S
#17
DAMN, you should've test fitted the blanket BEFORE hammering the strut tower
For what is worth, I run a T4 .84 housing, been doing it for 5 years or so, no issues; however my car was tuned by an experience tuner, AND I run water injection on to of the tune AND I only run 15psi on a T04S
For what is worth, I run a T4 .84 housing, been doing it for 5 years or so, no issues; however my car was tuned by an experience tuner, AND I run water injection on to of the tune AND I only run 15psi on a T04S
In any event, the deed is done and there's no going back now my friend. I am certain that a .85 housing wouldn't have caused my engine to blow up, but the gains can't be measured. I couldn't find any good information to help me make the "right" decision. All I had to work with was the opinion of Howard, which I value - and the understanding that rotary's typically have higher demand for flow to keep it safe and make the power you want.
Plus, the cost was a factor. This project started as a re-tooling of my fuel system to incorporate my CJM rails and larger primary injectors, a new intercooler and a retune. My original budget for this was about $1,000. After this is all said and done, this project will more than likely cost me 50% more than that and spending another $300 on a smaller turbine housing was just the final straw.
I think instead of dropping the turbine housing to a .85 to try and solve my lag issues, I will instead focus my efforts on optimizing my setup as best I can. Even with the relatively large turbine housing, I shouldn't have as much lag as I do, with the turbo being a dual ball bearing and all. So, I think I can help myself in other areas, like the WG spring, which I've already changed out.
Nick
#18
Racing Rotary Since 1983
iTrader: (6)
"Thermal conductivity is a material property describing the ability to conduct heat."
higher number =s more heat conductivity =s bad
Aluminum 205 (think LIM runners conducting heat into your charge air)
Steel 43
Stainless Steel 16
Titanium 22 (looks nice though)
Mica .71 (12 X 13 X 1/8th inch barrier about $65 McMaster Carr P/N 85165K81)
combine mica panel w a PTP Lava blanket and you are set.
picture tomorrow
higher number =s more heat conductivity =s bad
Aluminum 205 (think LIM runners conducting heat into your charge air)
Steel 43
Stainless Steel 16
Titanium 22 (looks nice though)
Mica .71 (12 X 13 X 1/8th inch barrier about $65 McMaster Carr P/N 85165K81)
combine mica panel w a PTP Lava blanket and you are set.
picture tomorrow
The following 2 users liked this post by Howard Coleman:
Brilliant7-LFC (07-20-17),
KNONFS (07-20-17)
#19
"Thermal conductivity is a material property describing the ability to conduct heat."
higher number =s more heat conductivity =s bad
Aluminum 205 (think LIM runners conducting heat into your charge air)
Steel 43
Stainless Steel 16
Titanium 22 (looks nice though)
Mica .71 (12 X 13 X 1/8th inch barrier about $65 McMaster Carr P/N 85165K81)
combine mica panel w a PTP Lava blanket and you are set.
picture tomorrow
higher number =s more heat conductivity =s bad
Aluminum 205 (think LIM runners conducting heat into your charge air)
Steel 43
Stainless Steel 16
Titanium 22 (looks nice though)
Mica .71 (12 X 13 X 1/8th inch barrier about $65 McMaster Carr P/N 85165K81)
combine mica panel w a PTP Lava blanket and you are set.
picture tomorrow
Nick
#20
Racing Rotary Since 1983
iTrader: (6)
'don't know from pic if this would help but...
the LIM has extraneous EGR passages cast into it and the only thing you need from the LIM is the runners. if you remove the LIM and have at it might you find clearance for the Mica barrier?
the LIM has extraneous EGR passages cast into it and the only thing you need from the LIM is the runners. if you remove the LIM and have at it might you find clearance for the Mica barrier?
#21
rotorhead
iTrader: (3)
On the subject of lag:
The size of the turbine housing determines how much exhaust energy it takes to generate boost (on low end) and is big determinant of backpressure on the high end, which affects power and knock.
Best way to think about it is this: If you floor it in 5th gear at say 3000rpm with the wastegate fully closed, the engine is very loaded down and all the exhaust is going to spin up the turbo. The size of the turbine housing has a big impact on how much boost you make there. It's less about how much time it takes to spin up the turbo, and more about how much energy it takes to do so. That's why the 2nd gen cars had a variable turbine A/R system and the 3rd gen cars had sequential turbos.
It takes less energy to get the turbo spinning with a smaller hotside, so if you are around town, going up hill in 5th gear you won't need to downshift so much.
Having a ball bearing turbo is what helps you in a transient situation, like going from off to on throttle as you shift, or if you are accelerating in a low gear and the engine isn't loaded down so much. If the turbine housing is too big to make the torque in a heavily loaded situation (5th gear WOT), the ball bearing isn't going to help.
The size of the turbine housing determines how much exhaust energy it takes to generate boost (on low end) and is big determinant of backpressure on the high end, which affects power and knock.
Best way to think about it is this: If you floor it in 5th gear at say 3000rpm with the wastegate fully closed, the engine is very loaded down and all the exhaust is going to spin up the turbo. The size of the turbine housing has a big impact on how much boost you make there. It's less about how much time it takes to spin up the turbo, and more about how much energy it takes to do so. That's why the 2nd gen cars had a variable turbine A/R system and the 3rd gen cars had sequential turbos.
It takes less energy to get the turbo spinning with a smaller hotside, so if you are around town, going up hill in 5th gear you won't need to downshift so much.
Having a ball bearing turbo is what helps you in a transient situation, like going from off to on throttle as you shift, or if you are accelerating in a low gear and the engine isn't loaded down so much. If the turbine housing is too big to make the torque in a heavily loaded situation (5th gear WOT), the ball bearing isn't going to help.
The following users liked this post:
Brilliant7-LFC (07-20-17)
#22
Rotary Motoring
iTrader: (9)
^^
Another factor that affects the "static" relationship of how much boost you can make per given rpm (what I call spool) is the compressor surge line on the compressor though.
On a turbo larger than about 57mm inducer on a rotary the surge line usually limits peak boost achievable per rpm no matter what you do with the hot side.
This has been driven home to us with the advent of the EFR turbos and their fast spooling Gamma-Ti exhaust wheels where when pushed the turbos hit the surge line so hard the car bucks.
A GT4088R is most definitely surge line limited on the typical rotary set-up in the low rpm (~0-4,000rpm).
Smaller exhaust side AR on GT4088R could help turbo transient operation (what I call response), but if the set-up is anywhere near optimal it should not affect the static relationship of peak boost per given rpm (spool).
Obviously, if you are asking a GT4088R to breath through a 2.5" exhaust with a cat a change from a 1.45AR to 0.85AR will positively affect spool as well as response.
I am talking about what we typically do with the rotary and turbos.
Another factor that affects the "static" relationship of how much boost you can make per given rpm (what I call spool) is the compressor surge line on the compressor though.
On a turbo larger than about 57mm inducer on a rotary the surge line usually limits peak boost achievable per rpm no matter what you do with the hot side.
This has been driven home to us with the advent of the EFR turbos and their fast spooling Gamma-Ti exhaust wheels where when pushed the turbos hit the surge line so hard the car bucks.
A GT4088R is most definitely surge line limited on the typical rotary set-up in the low rpm (~0-4,000rpm).
Smaller exhaust side AR on GT4088R could help turbo transient operation (what I call response), but if the set-up is anywhere near optimal it should not affect the static relationship of peak boost per given rpm (spool).
Obviously, if you are asking a GT4088R to breath through a 2.5" exhaust with a cat a change from a 1.45AR to 0.85AR will positively affect spool as well as response.
I am talking about what we typically do with the rotary and turbos.
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Brilliant7-LFC (07-20-17)
#23
On the subject of lag:
The size of the turbine housing determines how much exhaust energy it takes to generate boost (on low end) and is big determinant of backpressure on the high end, which affects power and knock.
Best way to think about it is this: If you floor it in 5th gear at say 3000rpm with the wastegate fully closed, the engine is very loaded down and all the exhaust is going to spin up the turbo. The size of the turbine housing has a big impact on how much boost you make there. It's less about how much time it takes to spin up the turbo, and more about how much energy it takes to do so. That's why the 2nd gen cars had a variable turbine A/R system and the 3rd gen cars had sequential turbos.
It takes less energy to get the turbo spinning with a smaller hotside, so if you are around town, going up hill in 5th gear you won't need to downshift so much.
Having a ball bearing turbo is what helps you in a transient situation, like going from off to on throttle as you shift, or if you are accelerating in a low gear and the engine isn't loaded down so much. If the turbine housing is too big to make the torque in a heavily loaded situation (5th gear WOT), the ball bearing isn't going to help.
The size of the turbine housing determines how much exhaust energy it takes to generate boost (on low end) and is big determinant of backpressure on the high end, which affects power and knock.
Best way to think about it is this: If you floor it in 5th gear at say 3000rpm with the wastegate fully closed, the engine is very loaded down and all the exhaust is going to spin up the turbo. The size of the turbine housing has a big impact on how much boost you make there. It's less about how much time it takes to spin up the turbo, and more about how much energy it takes to do so. That's why the 2nd gen cars had a variable turbine A/R system and the 3rd gen cars had sequential turbos.
It takes less energy to get the turbo spinning with a smaller hotside, so if you are around town, going up hill in 5th gear you won't need to downshift so much.
Having a ball bearing turbo is what helps you in a transient situation, like going from off to on throttle as you shift, or if you are accelerating in a low gear and the engine isn't loaded down so much. If the turbine housing is too big to make the torque in a heavily loaded situation (5th gear WOT), the ball bearing isn't going to help.
^^
Another factor that affects the "static" relationship of how much boost you can make per given rpm (what I call spool) is the compressor surge line on the compressor though.
On a turbo larger than about 57mm inducer on a rotary the surge line usually limits peak boost achievable per rpm no matter what you do with the hot side.
This has been driven home to us with the advent of the EFR turbos and their fast spooling Gamma-Ti exhaust wheels where when pushed the turbos hit the surge line so hard the car bucks.
A GT4088R is most definitely surge line limited on the typical rotary set-up in the low rpm (~0-4,000rpm).
Smaller exhaust side AR on GT4088R could help turbo transient operation (what I call response), but if the set-up is anywhere near optimal it should not affect the static relationship of peak boost per given rpm (spool).
Obviously, if you are asking a GT4088R to breath through a 2.5" exhaust with a cat a change from a 1.45AR to 0.85AR will positively affect spool as well as response.
I am talking about what we typically do with the rotary and turbos.
Another factor that affects the "static" relationship of how much boost you can make per given rpm (what I call spool) is the compressor surge line on the compressor though.
On a turbo larger than about 57mm inducer on a rotary the surge line usually limits peak boost achievable per rpm no matter what you do with the hot side.
This has been driven home to us with the advent of the EFR turbos and their fast spooling Gamma-Ti exhaust wheels where when pushed the turbos hit the surge line so hard the car bucks.
A GT4088R is most definitely surge line limited on the typical rotary set-up in the low rpm (~0-4,000rpm).
Smaller exhaust side AR on GT4088R could help turbo transient operation (what I call response), but if the set-up is anywhere near optimal it should not affect the static relationship of peak boost per given rpm (spool).
Obviously, if you are asking a GT4088R to breath through a 2.5" exhaust with a cat a change from a 1.45AR to 0.85AR will positively affect spool as well as response.
I am talking about what we typically do with the rotary and turbos.
I do have a 3" downpipe of course, but the wastegate is recirculated. I've considered having a new downpipe made with a dump instead, or simply modifying my own. My power goals for the time being are 425-450 whp, so perhaps the recirculated wastegate isn't a major factor at those levels?
I know from seeing Howard's writeup on his own manifold that the flow of exhaust gases is certainly affected by the design of the piping and to that end, my WG re-enters my 3" exhaust downstream at nearly a 90* which definitely isn't ideal. Perhaps a slight modification to the angle at which they meet from WG dump to exhaust would be necessary but I just don't know.
Nick
NOTE: My exhaust is 3" from downpipe to rear muffler, no resonators or cats in between.
Last edited by Brilliant7-LFC; 07-20-17 at 01:54 PM.
#24
Rotary Motoring
iTrader: (9)
If I understand you correct, you're basically saying that changing to the smaller A/R, so long as everything else is efficient enough, shouldn't make such a big difference from 0-4,000 RPMs...?
It is similar to going from 8.5CR to 10:1CR on the rotary. Makes a big difference in driving feel, but only a ~2% difference on the dyno sheet.
Might make a difference in dyno sheet as well if you are not able to drive the compressor to anywhere near the surge line.
--------
Here you can see that increasing the turbo exhaust side AR can actually increase low rpm power since it will increase engine VE and so shift the engine operating range to the Right of the surge line on the turbo compressor chart.
https://www.rx7club.com/single-turbo...558kw-1114618/
The chart on the Left shows 9180 1.05AR dyno in Red and the 9180 1.45AR dyno in Blue at the same boost in a back to back test.
In the lower part of the chart you can see the boost trace where the 1.45AR out spooled the 1.05AR exhaust housing.
Chart on Right shows final 1.45AR numbers with higher boost in Blue compared to the same old 1.05AR numbers in Red.
Still, boost response is snappier with the smaller 1.05AR exhaust housing.
The following users liked this post:
Brilliant7-LFC (07-20-17)
#25
Oh, it will make a difference in the turbo response which is what you feel but don't see on a dyno sheet.
It is similar to going from 8.5CR to 10:1CR on the rotary. Makes a big difference in driving feel, but only a ~2% difference on the dyno sheet.
Might make a difference in dyno sheet as well if you are not able to drive the compressor to anywhere near the surge line.
--------
Here you can see that increasing the turbo exhaust side AR can actually increase low rpm power since it will increase engine VE and so shift the engine operating range to the Right of the surge line on the turbo compressor chart.
The chart on the Left shows 9180 1.05AR dyno in Red and the 9180 1.45AR dyno in Blue at the same boost in a back to back test.
In the lower part of the chart you can see the boost trace where the 1.45AR out spooled the 1.05AR exhaust housing.
Chart on Right shows final 1.45AR numbers with higher boost in Blue compared to the same old 1.05AR numbers in Red.
Still, boost response is snappier with the smaller 1.05AR exhaust housing.
It is similar to going from 8.5CR to 10:1CR on the rotary. Makes a big difference in driving feel, but only a ~2% difference on the dyno sheet.
Might make a difference in dyno sheet as well if you are not able to drive the compressor to anywhere near the surge line.
--------
Here you can see that increasing the turbo exhaust side AR can actually increase low rpm power since it will increase engine VE and so shift the engine operating range to the Right of the surge line on the turbo compressor chart.
The chart on the Left shows 9180 1.05AR dyno in Red and the 9180 1.45AR dyno in Blue at the same boost in a back to back test.
In the lower part of the chart you can see the boost trace where the 1.45AR out spooled the 1.05AR exhaust housing.
Chart on Right shows final 1.45AR numbers with higher boost in Blue compared to the same old 1.05AR numbers in Red.
Still, boost response is snappier with the smaller 1.05AR exhaust housing.
In other news, I painted the "modified" strut tower support and will upload a couple pics tomorrow to show you fine gentlemen my skills with a hammer and can of VHT. I used the hi temp engine paint which I think should be fine. 550* is quite hot considering there will be a blanket on this bad boy soon...
I'm also running water lines to the turbo and am having a little difficulty clocking the CHRA, which is states you should do, to the tune of 20* to optimize the siphoning effect after shut down. With the blanket on, the temps inside the CHRA should be significantly higher after shut down and I'd like to utilize this integrated feature to lessen the fatigue on the bearings.
The bolts that go into the turbine housing appear to have been sort of chiseled so they don't back out and are locked down. I haven't tried turning them for fear of breaking them. Do you guys have any feedback for me on that? Should I just take it to a turbo shop and ask them to do it?
Thanks guys!
Nick