Turbo Manifold suggestions
#26
Junior Member
I feel for you. Even living here in the DFW metroplex area I can't hardly get anyone to answer their phone, call me back, or the few I did talk with to commit to an appointment I can count on just trying to get an hour or two of dyno time. I don't see it getting better any time soon either.
.
.
#27
Junior Member
Honestly you're likely to be just fine with the full-race one. I got the engine flanges and merge collector from Glease/Roiel and the shop doing my build fabbed the rest.
I guess the better WG placement is close to the turbine housing. My shop extended the WG neck a few inches away. When I asked why so far they said that they experienced premature failures in the WG's of their landspeed record car when the WG's were too close in. Knowing I want to turn this into a streetable track car (emphasis on track car) they took the extra precaution. I claim no real expertise, but I'd honestly think the full-race one is fine unless you REALLY want to punish your engine bay.
Mine for reference:
I guess the better WG placement is close to the turbine housing. My shop extended the WG neck a few inches away. When I asked why so far they said that they experienced premature failures in the WG's of their landspeed record car when the WG's were too close in. Knowing I want to turn this into a streetable track car (emphasis on track car) they took the extra precaution. I claim no real expertise, but I'd honestly think the full-race one is fine unless you REALLY want to punish your engine bay.
Mine for reference:
#29
Full Member
Thats the one I made in 2015 for the 8374EFR IWG.
Spools inpressive, better than stock ( may also be because of exhaust porting )
But gives you a litte boostcreep at 6500, I can give you graphs or numbers if you like.
By design what Turboblown made with the Turboblown Cast EFR IWG manifold should be quite the same
#30
Thats the one I made in 2015 for the 8374EFR IWG.
Spools inpressive, better than stock ( may also be because of exhaust porting )
But gives you a litte boostcreep at 6500, I can give you graphs or numbers if you like.
By design what Turboblown made with the Turboblown Cast EFR IWG manifold should be quite the same
Spools inpressive, better than stock ( may also be because of exhaust porting )
But gives you a litte boostcreep at 6500, I can give you graphs or numbers if you like.
By design what Turboblown made with the Turboblown Cast EFR IWG manifold should be quite the same
#31
Full Member
My target was to start with 10psi and later go up to 14psi.
The boost controller in my haltech didnt work properly which I didnt realise because I had the boost I wanted. :P
This it what it looked like in my very first run with the EFR (boost vs. rpm):
But boost creep can always be different, it depends a lot on air temps and so.
One time at a hill climb race I had high intercooler temps because of long waiting before the start, and there was no boost creep at all.
I ran with constant 6psi up the hill...this was when I first realized I had no boost control XD
I also had a run on the racetrack when my wastegate actuator came loose.
So WG was basicly open all the time and boost still creeped up to about 10psi at 6500, but I cant find the log data right now...
Last edited by PatrickT; 02-02-22 at 02:10 PM.
#32
10000 RPM Lane
iTrader: (2)
will this be an RX8-REW?
on the post above; high IATs could mean the tuning is cutting back engine performance for safety considerations, resulting in less power output. This may in turn result in less flow through the exhaust and then lessening the tendency to creep?
.
on the post above; high IATs could mean the tuning is cutting back engine performance for safety considerations, resulting in less power output. This may in turn result in less flow through the exhaust and then lessening the tendency to creep?
.
Last edited by TeamRX8; 02-02-22 at 04:38 PM.
#34
It was not bad at all, Ive got the low boost IWG, which opens at like 6-7psi but boost creeped to 10psi
My target was to start with 10psi and later go up to 14psi.
The boost controller in my haltech didnt work properly which I didnt realise because I had the boost I wanted. :P
This it what it looked like in my very first run with the EFR (boost vs. rpm):
But boost creep can always be different, it depends a lot on air temps and so.
One time at a hill climb race I had high intercooler temps because of long waiting before the start, and there was no boost creep at all.
I ran with constant 6psi up the hill...this was when I first realized I had no boost control XD
I also had a run on the racetrack when my wastegate actuator came loose.
So WG was basicly open all the time and boost still creeped up to about 10psi at 6500, but I cant find the log data right now...
My target was to start with 10psi and later go up to 14psi.
The boost controller in my haltech didnt work properly which I didnt realise because I had the boost I wanted. :P
This it what it looked like in my very first run with the EFR (boost vs. rpm):
But boost creep can always be different, it depends a lot on air temps and so.
One time at a hill climb race I had high intercooler temps because of long waiting before the start, and there was no boost creep at all.
I ran with constant 6psi up the hill...this was when I first realized I had no boost control XD
I also had a run on the racetrack when my wastegate actuator came loose.
So WG was basicly open all the time and boost still creeped up to about 10psi at 6500, but I cant find the log data right now...
#35
F'n Newbie...
iTrader: (6)
Unfortunately I don't know the science behind the "why" of it. I just know that, according to TurboSmart, the best location is as close to the turbo as possible and with a favorable transition angle.
I'd assume it's a combination of less turbulence, reduced likelihood of excess gas heading towards the turbo (cohesion), and perhaps response effectiveness?
Here's an interview where they talk about it: https://frontstreet.media/2019/04/26...ate-placement/
Last edited by fendamonky; 02-03-22 at 05:06 AM.
#36
Arrogant Wankeler
If it pulls timing there will be more exhaust energy from the same mass flow. It's almost certainly just a result of lower intake density = less mass flow = less exhaust flow and energy, especially if some elevation above baseline is involved too.
#37
Full Member
my motor is street port also. i ordered the Turblown EFR 8374 IWG kit and will be running Haltech 1500. so pretty much similar setup as your, which is why i asked. but 10 psi boost creep is not bad. i do want the ability to turn it down as much as i can if i decide to take the car on road course. interesting that the boost creep taper down after 6k tho. usually boost creep is a run away train and keeps going up. my current setup has boost creep past 14 psi, so i end up running a 2.75" restrictor plate in a 3" exhaust to keep the boost creep down. it's a greedy style manifold, i guess the WG port cant flow enough for street port engine.
Ive got a bridgeport but I also dont know why it is dropping back, but I also had some strange noise from 6000rpms on, sounds like flow dependent.
Thats also why I made the custom intake manifold, lets see what difference this will make ( in boost creep and noise )
In boost creep your boost is not controlled anymore and can be affected by the slightest changes.
My opinion is also, what gives you more power also results in more boost creep...
The following users liked this post:
Slides (02-03-22)
#38
10000 RPM Lane
iTrader: (2)
Unfortunately I don't know the science behind the "why" of it. I just know that, according to TurboSmart, the best location is as close to the turbo as possible and with a favorable transition angle.
I'd assume it's a combination of less turbulence, reduced likelihood of excess gas heading towards the turbo (cohesion), and perhaps response effectiveness?
Here's an interview where they talk about it: https://frontstreet.media/2019/04/26...ate-placement/
I'd assume it's a combination of less turbulence, reduced likelihood of excess gas heading towards the turbo (cohesion), and perhaps response effectiveness?
Here's an interview where they talk about it: https://frontstreet.media/2019/04/26...ate-placement/
Thank you for taking the time to explain it. However, that seems like possibly a misinterpretation to me. Because the typical 13B as well as your own manifold differ in that there is no collector (possibly go back and read the specifics of the example being provided in the link), but two individual pipes feeding directly and independently, each into a separated port of a twin scroll turbine, and each pipe with it’s own wastegate. The pipes on this manifold are not so long, and this particular point is not likely that great, but on a manifold with longer pipes the WG placement at the turbine then results in all the flow having to go through those pipes before dumping off the excess flow. If the WGs are instead positioned as close to the exhaust port as possible, then it’s instead dumping the excess off early and only flowing the lesser amount of exhaust energy up the pipes to the turbine.
Understand that backpressure results from the amount of flow in a pipe coupled with it’s diameter, length, turns, etc. By routing all the flow all the way up to the turbine; rather than dumping the excess off sooner and only flowing the lesser amount needed through them, is potentially resulting in more emap at the exhaust port/engine. So in the case of longer pipes of smaller ID this is going to come more into play. Again, the exhaust pipes aren’t that long on this particular manifold, but as nice of a fab job as it is, what I see is that placing the WGs at the turbine results in not just extra fabrication effort and cost, but also the long contorted paths of the WG pipes is radiating a lot of heat energy up higher in the engine bay and in close proximity of the intake manifold. As opposed to the WGs and their shorter, less contorted pipe routing being positioned down close to the exhaust ports, lower in the engine bay, underneath the manifold, and away from the intake manifold.
It’s not intended as a criticism, but just my observation based on those principles.
Because wrt the linked article, when there are say four pipes feeding into a collector and the collector feeding into the turbine, then what was proposed makes sense. If you have the WG positioned close to where the multiple pipes enter the collector, then it may favor only the flow of the closest pipes to it, which is going to bias total collected flow to the turbo rather than the WG. Putting it closer to the turbine as presented then helps to avoid that situation and puts the WG in a better position for the flow of all the pipes to have access to the WG. So again, in the case of only two exhaust pipes; each with it’s own wastegate, it’s not the same thing. Most collectors aren’t as long and snaking around as some 13B exhaust pipes are. If they were though, then imo the same thing would apply; placing the WG position earlier in the collector, but not too close to where the multiple pipes enter and biasing it to only part of the flow, would be preferred rather than at the far end at the turbo. There are other factors though; space constraints and such, which might limit where the WG has to be. Looking at your manifold though, there seems to be room down low for dual WG placement.
in the case of a 13B with dual WGs and twin scroll, and depending on the power goal, it could be argued that having 2” pipe exiting the port to the WG and then reducing down after it with 1.5” to the turbine would be preferred. I don’t share in the ideas I’ve seen presented about the piping length between WG and turbine.
that’s how I see it anyway feel free to voice counter/opposing views
.
Last edited by TeamRX8; 02-03-22 at 09:53 AM.
#39
i tend to agree with that logic. since having separate runner and WG for each of the twin scroll, the exhaust pressure should be same on both side. pressure is going to travel the path of least resistance and getting that excess pressure out sooner rather than later is probably more efficient.
#40
Full Member
I see no fault in placing the WG close to the turbo, because exhaust temps may drop on the path from the exhaust port to the turbo.
So first the WG sees lower temps, and second the WG sees the same temps thus density (maybe even pressure ) as the turbo, so boost control may be more consistent.
Otherwise it may give you varying boost (or at least WG duty) for hot and "cold" exhaust.
Just my idea...
So first the WG sees lower temps, and second the WG sees the same temps thus density (maybe even pressure ) as the turbo, so boost control may be more consistent.
Otherwise it may give you varying boost (or at least WG duty) for hot and "cold" exhaust.
Just my idea...
#41
F'n Newbie...
iTrader: (6)
Marty's statement of "The ideal location for the wastegate is as close to the turbine housing as possible, and in a manner that provides a good flow path into the wastegate" is pretty cut and dry though.
Obviously it isn't the end of the world to have the WG's right at the exhaust ports, plenty of folks have done it without catastrophic failures. That would definitely be an interesting test to run though, comparing two manifolds back to back with the only variable being the location of the WG runners.
The following users liked this post:
Slides (02-03-22)
#44
Rotary Motoring
iTrader: (9)
My experience with locating the WGs close to the exhaust port VS close to the turbo (so talking either end of exhaust runners) is that it all affects boost control.
Boost control is the primary function for the WG.
_____
On the peripheral exhaust port rotary application, WG position closer to the turbo makes high rpm boost creep more likely.
In the higher RPMs there is a higher volume of exhaust gas by the time it travels to the wastegate/turbo because peripheral exhaust port rotaries have plentiful external combustion in the higher RPMs.
The higher volume of exhaust gas further from the exhaust port means higher velocity per given runner diameter, so WG priority/size is even more important.
*Aside- this is also why long runner exhausts are preferred on a big turbo rotary. Get big turbo spooled sooner (but remember big turbo spooling in the high rpm range unlike a smaller turbo which spools in low rpm range where external combustion effect is not as strong).*
_________
WG close to rotary peripheral exhaust port makes high rpm boost drop off more likely.
Dynamic exhaust manifild pressure is much higher near the exhaust port (not talking about a static/time weighted average pressure). These high pressure pulses pushing on the bottom of the WG poppet valve tend to keep the WG valve open in the higher RPMs. Its WG valve float.
*Aside- these dynamic high pressure pulses near the exhaust port are what can help spool a smaller turbo in the low RPM on a rotary and Mazda developed straight bladed "impact" turbines with Hitachi to maximize the affect.
______
So, like everything else; WG position is a balance in my experience.
Boost control is the primary function for the WG.
_____
On the peripheral exhaust port rotary application, WG position closer to the turbo makes high rpm boost creep more likely.
In the higher RPMs there is a higher volume of exhaust gas by the time it travels to the wastegate/turbo because peripheral exhaust port rotaries have plentiful external combustion in the higher RPMs.
The higher volume of exhaust gas further from the exhaust port means higher velocity per given runner diameter, so WG priority/size is even more important.
*Aside- this is also why long runner exhausts are preferred on a big turbo rotary. Get big turbo spooled sooner (but remember big turbo spooling in the high rpm range unlike a smaller turbo which spools in low rpm range where external combustion effect is not as strong).*
_________
WG close to rotary peripheral exhaust port makes high rpm boost drop off more likely.
Dynamic exhaust manifild pressure is much higher near the exhaust port (not talking about a static/time weighted average pressure). These high pressure pulses pushing on the bottom of the WG poppet valve tend to keep the WG valve open in the higher RPMs. Its WG valve float.
*Aside- these dynamic high pressure pulses near the exhaust port are what can help spool a smaller turbo in the low RPM on a rotary and Mazda developed straight bladed "impact" turbines with Hitachi to maximize the affect.
______
So, like everything else; WG position is a balance in my experience.
The following users liked this post:
PatrickT (02-04-22)
#45
Full Member
Good content !
But your recommention towards longer runners only counts for PP engines?
Because I thought shorter is better for spool to make use of the exhaust pulses ( in twin scroll )
Or is a 8374 already considered a small turbo on a 13B ?
But your recommention towards longer runners only counts for PP engines?
Because I thought shorter is better for spool to make use of the exhaust pulses ( in twin scroll )
Or is a 8374 already considered a small turbo on a 13B ?
#47
Rotary Motoring
iTrader: (9)
Peripheral exhaust port rotaries (1967-2002 engines).
Yeah, 8374 is a small turbo on a rotary that spools in the low rpm and will benefit from short runners for spool.
Large turbos are the T6 flanged 1,000+ hp turbos that drag racers have typically used on the rotary and cant/dont spool below 5,000rpm.
Road racers may sometimes use long runner manifolds with small/medium frame turbos to lower exhaust manifold pressure for reliability at the expense of spool/response.
Typically long/medium runner manifolds are most popular just to fit a decent sized turbo in the narrow FD engine bay.
Yeah, 8374 is a small turbo on a rotary that spools in the low rpm and will benefit from short runners for spool.
Large turbos are the T6 flanged 1,000+ hp turbos that drag racers have typically used on the rotary and cant/dont spool below 5,000rpm.
Road racers may sometimes use long runner manifolds with small/medium frame turbos to lower exhaust manifold pressure for reliability at the expense of spool/response.
Typically long/medium runner manifolds are most popular just to fit a decent sized turbo in the narrow FD engine bay.
Last edited by BLUE TII; 02-06-22 at 09:08 PM.
The following users liked this post:
PatrickT (02-08-22)
#48
10000 RPM Lane
iTrader: (2)
The same reason you need a big turbo for a PP exemplifies the counter reason it won’t work if there is too much flow restriction through the engine. In that case the way-big turbo is too restricted and before the engine can get going fast enough to let the flow through then it will just back up into the compressor inlet, i.e. lag.
Except in the situation below I don’t think it’s been recognized yet that it’s not just the IC, but *everything* downstream of it too
https://www.rx7club.com/3rd-generati.../#post12499791.
honestly though, I’m still not sold on the manifold pipe length reasoning rather than it being a result of other factors.
.
Except in the situation below I don’t think it’s been recognized yet that it’s not just the IC, but *everything* downstream of it too
https://www.rx7club.com/3rd-generati.../#post12499791.
honestly though, I’m still not sold on the manifold pipe length reasoning rather than it being a result of other factors.
.
Last edited by TeamRX8; 02-07-22 at 02:58 AM.
#49
Full Member
Good I have a small turbo then bc I do race on circuit
Last year I was mapping my new CNG secondaries on an abandoned soviet air field
and to trigger the secondaries on my haltech I pressed gas and brakes to build ealy boost.
You can see the vertical lines at 1500, 2000 and 2500
Later I did some spool tests in 4th gear, where I reached target boost ( 1800mbar ) from 3200.
And in normal racing, full boost is there from 3600 on
For circuit racing this is perfect for me, I'm normally not reving below 3500.
For drag racing this may be not necassary to have this early spool, and for street driving it's maybe to laggy for some people...
-Patrick
Last year I was mapping my new CNG secondaries on an abandoned soviet air field
and to trigger the secondaries on my haltech I pressed gas and brakes to build ealy boost.
You can see the vertical lines at 1500, 2000 and 2500
Later I did some spool tests in 4th gear, where I reached target boost ( 1800mbar ) from 3200.
And in normal racing, full boost is there from 3600 on
For circuit racing this is perfect for me, I'm normally not reving below 3500.
For drag racing this may be not necassary to have this early spool, and for street driving it's maybe to laggy for some people...
-Patrick
The following 4 users liked this post by PatrickT:
#50
Thread
Thread Starter
Forum
Replies
Last Post