GT37 How does it size up to rotary?
Originally posted by Roro
Nope. It used a GT35 turbine and a GT40 compressor. This is the reason that it was controversial... The rx7 does like a large exhaust (generally) and putting a T3 type turbine section raised lots of eyebrows.
Plus, the GT40 was not available with a BB CHRA. So for the people who wanted to run the GT40 compressor with a dual BB CHRA the option was a 35CHRA and turbine hence the 35/40, 35R combo.
-Chris
Nope. It used a GT35 turbine and a GT40 compressor. This is the reason that it was controversial... The rx7 does like a large exhaust (generally) and putting a T3 type turbine section raised lots of eyebrows.
Plus, the GT40 was not available with a BB CHRA. So for the people who wanted to run the GT40 compressor with a dual BB CHRA the option was a 35CHRA and turbine hence the 35/40, 35R combo.
-Chris
The fact that it came with a T3 flange shouldn't raise anyones eyebrows, while RX7's do favor larger exhaust housings it wasn't made for the RX7, those that say it's to small need to understand that bigger isn't always better. You could get a broader power curve under the smaller housing at expense of peak power and slightly higher exhaust temps.
-Sean
Last edited by Zero R; Jan 20, 2004 at 09:16 PM.
Originally posted by BLUE TII
The "possibility" of a 400RWHP + single turbo w/ better boost response than the 3rd gen sequential twins is what really has my interest. No one knows how realistic that "possibility" is at this point.
[/B]
The "possibility" of a 400RWHP + single turbo w/ better boost response than the 3rd gen sequential twins is what really has my interest. No one knows how realistic that "possibility" is at this point.
[/B]
Last edited by Zero R; Jan 20, 2004 at 09:25 PM.
Originally posted by Roro
Mating a BB CHRA to the VGT turbine housing has nothing to do with your ability to machine parts. The maching that you had done is essentially standard for any turboshop.
It may just be physically impossible. For example, I can tell you that you can't take a standard Garrett T4 turbine housing and machine it to fit a BB CHRA. I'm pretty sure Sean will tell you the same thing. Not because we didn't have expereinced machinsts, but because the Garrett BB chra is vastly different from a convential journal bearing design. Getting the BB chra to fit in the correct axial location wrt/ the turbine housing requires a great amount of material removal. So much in fact, that there isn't enough, and you machine it all away and the housing falls apart.
He isn't saying that it's impossible, just not probable.
-Chris
Mating a BB CHRA to the VGT turbine housing has nothing to do with your ability to machine parts. The maching that you had done is essentially standard for any turboshop.
It may just be physically impossible. For example, I can tell you that you can't take a standard Garrett T4 turbine housing and machine it to fit a BB CHRA. I'm pretty sure Sean will tell you the same thing. Not because we didn't have expereinced machinsts, but because the Garrett BB chra is vastly different from a convential journal bearing design. Getting the BB chra to fit in the correct axial location wrt/ the turbine housing requires a great amount of material removal. So much in fact, that there isn't enough, and you machine it all away and the housing falls apart.
He isn't saying that it's impossible, just not probable.
-Chris
-Sean
Here is the correct compressor maps
http://www.atpturbo.com/root/maps/gt35r.htm
http://www.atpturbo.com/root/maps/gt40r.htm
http://www.atpturbo.com/root/maps/gt35r.htm
http://www.atpturbo.com/root/maps/gt40r.htm
Last edited by Jesuscookies; Jan 20, 2004 at 09:30 PM.
As far as no WG? That assumes that the VGT at it's largest point is sufficiently large to prevent creep... and I wouldn't bet on that until it's been tried in our application. May work, may not, won't know till you try it.
-ch
Zero R
Hmm, I am too turbo ignorant to figure out internet turbo fact from fiction. For instance I read that GT35 used T04S compressor housing in .70 A/R?
So, machining not likely for help fit BB GT center on plain bearing GT exhaust housing- damn. Probably just as well since the lower price of a plain bearing rebuild will help persuade me to have this used VGT unit rebuilt.
Hey, I don't mind you letting me know when I am sounding like an ***. That way if I don't mean to be an *** I can let you know; and if I do mean to be an *** I can let you know
Roro
Hyperion
No wastegate needed if VGT works as designed.... I was thinking of using my WG and Pop-off valve incase VGT sticks in the "spool-up" mode- at least for the initial tests. VGT would be operating at ~twice the EGT it is designed for.
This is my biggest worry (obviously, since I keep mentioning it).
As far as anit-lag measures- this new electronically controlled VGT will be in whatever position it is told to be in. So if you have a "race" setting that puts the VGT in "spool-up" position anytime it is under the max desired boost you should be able to get boost w/ out load and use normal antilag measures if it is not full desired boost.
Zero R
Yeah, I can relate to wheelspin woes from my current set-up- gotta shortshift 1st and 2nd before boost comes on hard and expect the rear to come out in 3rd. AutoX- how?
But, I wasn't thinking that would be any more of a problem w/ VGT in lower rpms. I think the engine would have to work against the exhaust restriction of the VGT in "spool-up" position. So by having full boost at say 2,000rpm you may have more power than a turbo w/ no boost at 2,000- but nowhere near full power.
When my TII had stock turbo, intake and exhaust mods it could achieve full boost at 2,00rpm- but it wouldn't "take off" untill 3,000rpm.
So, why VGT then? I like the feeling of very fast boost response- feels like a larger engine. For instance, when I am cruising on the interstate ~4,000rpm w/ current set-up the boost response is so instant it is twitchy. Bad for gas mileage, but great for having fun. I would like that boost response right off idle- when I choose.
My VGT set-up wouldn't be for racing where the boost response should be great in the RPM range the engine will be operating w/ a standard turbo anyways. Besides which, VGT has been outlawed from most major turbo race classes anyways (a testimonial to its effectiveness?)
The 35R uses a different size comp.wheel than the 40R, so no the maps are not the same, the main reason for the 35/40 designation is because it uses a larger GT40 series comp. cover this is the main reason for this. While I haven't had a chance to compare the two side by side my guess is that once given the chance machining won't solve the problem. I could be wrong. As far as sounding like a *** maybe we just misunderstood each other so no harm no foul.
So, machining not likely for help fit BB GT center on plain bearing GT exhaust housing- damn. Probably just as well since the lower price of a plain bearing rebuild will help persuade me to have this used VGT unit rebuilt.
Hey, I don't mind you letting me know when I am sounding like an ***. That way if I don't mean to be an *** I can let you know; and if I do mean to be an *** I can let you know
Roro
As far as no WG? That assumes that the VGT at it's largest point is sufficiently large to prevent creep... and I wouldn't bet on that until it's been tried in our application. May work, may not, won't know till you try it.
The VGT geometry actually allows the effective A/R to go to zero, i.e., 100% of the flow bypasses the turbine. So creep isn't an issue. Unfortunately, this means that the turbo probably won't respond to anti-lag measures for all you drag racers or rally drivers out there...
This is my biggest worry (obviously, since I keep mentioning it).
As far as anit-lag measures- this new electronically controlled VGT will be in whatever position it is told to be in. So if you have a "race" setting that puts the VGT in "spool-up" position anytime it is under the max desired boost you should be able to get boost w/ out load and use normal antilag measures if it is not full desired boost.
Zero R
My semi-educated guess is massive wheelspin but that would depend on just how hard the boost comes in, and if it comes in too soft at that point did you really benifit.Sure would be fun though.
But, I wasn't thinking that would be any more of a problem w/ VGT in lower rpms. I think the engine would have to work against the exhaust restriction of the VGT in "spool-up" position. So by having full boost at say 2,000rpm you may have more power than a turbo w/ no boost at 2,000- but nowhere near full power.
When my TII had stock turbo, intake and exhaust mods it could achieve full boost at 2,00rpm- but it wouldn't "take off" untill 3,000rpm.
So, why VGT then? I like the feeling of very fast boost response- feels like a larger engine. For instance, when I am cruising on the interstate ~4,000rpm w/ current set-up the boost response is so instant it is twitchy. Bad for gas mileage, but great for having fun. I would like that boost response right off idle- when I choose.
My VGT set-up wouldn't be for racing where the boost response should be great in the RPM range the engine will be operating w/ a standard turbo anyways. Besides which, VGT has been outlawed from most major turbo race classes anyways (a testimonial to its effectiveness?)
No, haven't recieved turbo yet.
I was looking at the Ford 6.0 manual again.
It appears the VGTCV (control valve) is right on the turbo itself. It is a simple duty cycle control solenoid that moves a piston in the valve body. The piston in the valve opens and closes ports that allow the high pressure oil to go to either side of the VGT vane's piston.
So, in other words it looks good for two reasons.
1) The duty cycle controlled solenoid is relatively easy to modulate.
2) The hydraulic vane positioning appears to be a push pull operation. Hydraulic force to move vanes in either direction- so decreasing the chance of sticking/seizing.
I am not sure how I will provide high pressure oil yet. Don't know what pressure the Ford system uses- doubt the ~120psi of the rotary is enough; it won't hurt to have more (uless it causes a leak).
I might have to use an engine driven pump and regulator. I was envisioning one of the engine driven fuel pumps pumping powersteering fluid...
I was looking at the Ford 6.0 manual again.
It appears the VGTCV (control valve) is right on the turbo itself. It is a simple duty cycle control solenoid that moves a piston in the valve body. The piston in the valve opens and closes ports that allow the high pressure oil to go to either side of the VGT vane's piston.
So, in other words it looks good for two reasons.
1) The duty cycle controlled solenoid is relatively easy to modulate.
2) The hydraulic vane positioning appears to be a push pull operation. Hydraulic force to move vanes in either direction- so decreasing the chance of sticking/seizing.
I am not sure how I will provide high pressure oil yet. Don't know what pressure the Ford system uses- doubt the ~120psi of the rotary is enough; it won't hurt to have more (uless it causes a leak).
I might have to use an engine driven pump and regulator. I was envisioning one of the engine driven fuel pumps pumping powersteering fluid...
Joined: Apr 2002
Posts: 4,232
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From: Rotaryland, New Hampshire
Ive been following along with this thread sence its beginning and have become intreasted enought to look around for information on my own
i was browsing ebay at one point and found a bunch of auctions for a GT37 E-VNT Turbocharger, all the #'s you have spouted out in the 2 pages match up, however the name is diff, is it the same item?
-Jacob
i was browsing ebay at one point and found a bunch of auctions for a GT37 E-VNT Turbocharger, all the #'s you have spouted out in the 2 pages match up, however the name is diff, is it the same item?
-Jacob
Yeah, that is what the guy that has access to them is calling them. That is not their name.
Every source including the Ford 6.0 manual calls them VGT (Variable Geometry Turbo.)
VNT was another Garrett turbo- Variable Nozzle Turbo, I believe. VNT 25 in dodge cars '89,'90.
Hmm, looking at the description in his auctions the exhaust vanes are held in the open position by spring tension and closed by hydraulic pressure. That is not as cool... damn.
Every source including the Ford 6.0 manual calls them VGT (Variable Geometry Turbo.)
VNT was another Garrett turbo- Variable Nozzle Turbo, I believe. VNT 25 in dodge cars '89,'90.
Hmm, looking at the description in his auctions the exhaust vanes are held in the open position by spring tension and closed by hydraulic pressure. That is not as cool... damn.
I wonder what the Ford 6.0 is using the high-pressure oil for besides the turbo control? I mean, if it's just for the turbo, maybe whatever unit is on the Ford would work....
-ch
-ch
spoon!
Joined: Sep 2002
Posts: 1,208
Likes: 50
From: Dousman, WI
Heh, just thought I'd post in this. I've been reading a similar thread on the Supraforums where a guy got ahold of a pair of these turbos. It had a smattering of good technical info.
First off, they only need 55-60psi of oil pressure. The vanes are controlled by a 100hz signal; PWM works, but current works better. 70% is about full closed (small AR) 25% about full open. The compressor's a 50trim GT40.
Now, the problem. EGTs. They're rated to 1400 degrees continuous, 1500 intermittent. Now, I don't know what kind of temperatures the turbo motors are putting out, but I know I saw more than that on our ITA 1st gen.
http://www.supraforums.com/forum/sho...hreadid=159110 is the thread if anyone's interested.
Heh, someone remind me to corner and question to death a Garrett rep at the SAE convention this March.
First off, they only need 55-60psi of oil pressure. The vanes are controlled by a 100hz signal; PWM works, but current works better. 70% is about full closed (small AR) 25% about full open. The compressor's a 50trim GT40.
Now, the problem. EGTs. They're rated to 1400 degrees continuous, 1500 intermittent. Now, I don't know what kind of temperatures the turbo motors are putting out, but I know I saw more than that on our ITA 1st gen.
http://www.supraforums.com/forum/sho...hreadid=159110 is the thread if anyone's interested.
Heh, someone remind me to corner and question to death a Garrett rep at the SAE convention this March.
spoon!
Joined: Sep 2002
Posts: 1,208
Likes: 50
From: Dousman, WI
Oh, funny thought I just had about wheelspin. This is obviously kinda advanced in some ways but... why not have a traction control system talking to everything else? If boost is coming on fast enough to break traction, open up the vanes a bit and slow it down. Okay, that probably wouldn't respond fast enough on its own, so add... I'm pretty sure they make electronic dump valves for the intake side, I recall some turbo Ford guys talking about it to keep out of compressor surge regions.
Anyway, just a thought.
Anyway, just a thought.
Kenku, thanks for posting that thead on Supra forums!
I will have to sign up over there just to learn/contribute to this research once I get my VGT.
I had thought of this as well. Seems like VGT actuation could be the only traction control you would need short of when driving on ice since our cars are so anemic w/ out boost (doh, sorry NA guys).
In my theoretical "race" mode where VGT is varying vanes to the smallest A/R feasable to keep boost constant at max desired PSI...
I wonder if the vanes "clamping down" when you back off the throttle a bit as the VGT tries keep boost up will add to the driveability or finess. You know, a little less of the "all or nothing" personality turbos can have when in their responsive engine RPM zone. So when you get wheel spin you can let off a bit w/ out the turbo falling on its face as they are apt to do.
I guess what I am saying is you could have a more progressive drop in engine power as the VGT could be going from 100% throttle @ 20psi modulated to 75% throttle still @ 20psi, whereas standard turbo may be going from 100% throttle @ 20psi but when modulated to 75% throttle boost drops like a rock!
Purely conjectural at this point, but these dreams are what will keep me going when I am feeling way in over my head in this project.
I will have to sign up over there just to learn/contribute to this research once I get my VGT.
Oh, funny thought I just had about wheelspin. This is obviously kinda advanced in some ways but... why not have a traction control system talking to everything else? If boost is coming on fast enough to break traction, open up the vanes a bit and slow it down.
In my theoretical "race" mode where VGT is varying vanes to the smallest A/R feasable to keep boost constant at max desired PSI...
I wonder if the vanes "clamping down" when you back off the throttle a bit as the VGT tries keep boost up will add to the driveability or finess. You know, a little less of the "all or nothing" personality turbos can have when in their responsive engine RPM zone. So when you get wheel spin you can let off a bit w/ out the turbo falling on its face as they are apt to do.
I guess what I am saying is you could have a more progressive drop in engine power as the VGT could be going from 100% throttle @ 20psi modulated to 75% throttle still @ 20psi, whereas standard turbo may be going from 100% throttle @ 20psi but when modulated to 75% throttle boost drops like a rock!
Purely conjectural at this point, but these dreams are what will keep me going when I am feeling way in over my head in this project.
Hmm, I've never measured myself but "common wisdom" on the board is that peak power on the 13BT is close to 1750. Can anyone confirm or deny this?
This is definitely my biggest concern. I will run the 60mm wastegate and pop-off valve in the initial set-up. I will know if the vanes are sticking w/ out it putting my engine at risk. If they stick the 1st thing I will do is take the turbo off (hey, V-bands will be quick) and clearance everything a bit more (grind grind).
And if that doesn't help, ????
Well, it should. What are EGTs going to do besides expand the metal? The robust stainless pieces can definitely take the heat as can the cast iron.
Nothing new on this turbo- except some pics. I will most likely not be able to continue on w/ this project as I will be moving down to SF Bay Area and looking for new job and such. I just have to concentrate on getting my current set-up working right before I can move.
Here is a shot of GT37 VGT w/ a stock TII turbo next to it for reference sake.
This one shows the VGT hydraulic actuator housing cast into the turbo center.
Here are the VGT vanes in the "closed" position or spool-up position.
The vanes in "open" position or low restriction position.
This shows the "unison ring" that moves the vanes together and provides the front wall of the turbo nozzle.
This rear shot shows the eccentric pin that actuates the unison ring. On the other side of the exhaust backing plate the eccentric pin has a pinion gear on it that engages a rack attached to the hydraulic piston. Engine oil is directed to one side of the piston or the other to vary the angle of the VGT vanes.
The piston/rack
The solenoid valve that directs the engine oil.
Here is a shot of GT37 VGT w/ a stock TII turbo next to it for reference sake.
This one shows the VGT hydraulic actuator housing cast into the turbo center.
Here are the VGT vanes in the "closed" position or spool-up position.
The vanes in "open" position or low restriction position.
This shows the "unison ring" that moves the vanes together and provides the front wall of the turbo nozzle.
This rear shot shows the eccentric pin that actuates the unison ring. On the other side of the exhaust backing plate the eccentric pin has a pinion gear on it that engages a rack attached to the hydraulic piston. Engine oil is directed to one side of the piston or the other to vary the angle of the VGT vanes.
The piston/rack
The solenoid valve that directs the engine oil.
Last edited by BLUE TII; Apr 26, 2004 at 02:01 AM.
looks pretty promising if you can get it to work correctly
Full Member
Joined: Jun 2002
Posts: 236
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From: Seattle, WA
I have a GT37V center section and am trying to build a controller for it in my spare time. If anyone knows what kindof signal the solenoid takes to move it, it would be very helpful. I can do it using the guess & check method, but I don't wanna damage the only test model I have. Any information will be useful, thanks,
Nick
Nick
Full Member
Joined: Jun 2002
Posts: 236
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From: Seattle, WA
Ok, I missed a post farther up... my bad. Anyway, for the heat problem, has anyone thought of thermal coating the vane system in the exhaust half? I know you'd have to remove a material from all the sides to keep tolarances, but it may help a little.
