GT37 How does it size up to rotary?
 

I am interested in adapting a Garrett GT37 VGT off of a 2003 Ford Powerstroke diesel 6.0 liter for my car.

But, how would it size up to the rotary?

Looks like it is-

52 trim compressor wheel w/ 54.8mm inducer, 76.0mm exducer in a .58 compressor A/R

84 trim exhaust wheel w/ 66.4mm exducer, 72.5mm major dia. in an undivided .90 A/R housing- but w/ variable angle vanes in the housing that affect the funtional A/R for quick spool up and low restriction as needed.

I found a source of used units for ~$300 each or discounted for more.

I know it is going to be some work to get the hydraulic VGT vanes to operate. I was thinking a master cylinder actuated by a linear motor or cammed stepper motor. I work at an industrial electric control manufacturing facility so one of the friendly engineers could help me w/ the control aspect.

Also, it is a bummer that it is non-divided. I figure a long long runner manifold and that VGT will more than make up for the non-divided housing.

Also, even the very robust stainless vanes and shafts may sieze up as the cooled EGR diesels run only ~850 deg exhaust temps. I will include my 60mm WG in the design and my Pop-off valve incase of VGT failure.

Only thing bugging me now is that it looks like the GT37 compressor flows less than the 60-1 HiFi I have now?

Didn't sound right to me but the source I found stated 50 Lb/min for the GT37 and 63 Lb/min for the T04B 60-1 HiFi?

I am running 17psi on the 60-1 HiFi and love the power- don't want to take a step down. Or would the added efficiency of the GT series compressor allow one to up the boost w/ same safety factor.

Any input appreciated. If I get one of these working it could be our new hot set-up.

If that VGT really works we are looking at twin GT37s :eek: Ha ha, probably not.

I have heard these turbos are LOUD from the Powerstroke boys. I guess you hear the turbo whine blocks before you hear the diesel engine on these trucks once you get an open intake/exhaust.

Plus the VGT provides enough exhaust backpressure when closed down that you get compression braking. Woo hoo Jake brake for the RX-7... Well, it would be nice to get a little more engine braking for throttle lift rotation in cornering corrections.

Lemme post some helpful maps from Garrett. GT40 compressor.

GT40 turbine map.

GT35 compressor map.

GT35 turbine map.

the gt37 looked like its a little smaller than an o trim, which is a little larger than stock, so it looks like a good upgrade for the s5 based turbo.

GT37 compressor map.

GT37 turbine map.

So, here is a 35/40:

https://www.rx7club.com/attachment.p...postid=2560881 https://www.rx7club.com/attachment.p...postid=2560630

and the GT40:

https://www.rx7club.com/attachment.p...postid=2560630
https://www.rx7club.com/attachment.p...postid=2560687

(Why are people running this turbo? Peak HP only...)

and the GT37

https://www.rx7club.com/attachment.p...postid=2560900
https://www.rx7club.com/attachment.p...postid=2560930

It looks like the 37 is well-sized for the 13B. Note that the compressor map doesn't change too much based on A/R. It really makes me wonder why no one has made just a straight GT37 kit for the FD, but I like the VGT idea much more.

-ch

Thanks for posting all those maps Hyperion.

That GT37 compressor maps w/ GT37 76mm, GT37 82mm and T04 76mm was the only one I found as well when searching for GT37.

So hard to read I didn't bother attaching it :(

But, yeah- it slots in nicely right between the GT35 and GT40. I wondered why nobody does a straight GT37 swap on single turbo as well since there is always debate whether to go w/ limited HP of GT35 or lag of GT40.

If the VGT can be adapted there is no reason one couln't swap in the GT40 compressor section onto the GT37 VGT turbo, right?

nobody seems to list the gt37, that might be ones reason

BLUE: You're right, although I do like the surge line on the 76mm GT37. It's interesting that the maps for the other turbos go out only to 65%, but the GT37 has data out to 60%. That said, I think with intercooling you could push 60lbs through the GT37, good for close to 475 RWHP.

I'm most concerned about finding a solution to turbo control. How do they do it on the Ford diesels?

-ch

Could you clarify what limited HP and lag are by your definitions.... since different people want different thing.

The 35R has been shown to make 400-450RWHP and is claimed by "those in the know" to be one of the best spooling turbo's on the market.

There is very little lag on the 40R when compared to the 35R also the 37 is nonBB, the maps you chose for the 35/40 are wrong also. My question is other than taking up the challange of making it work and being a little unique(both good reasons) why? Price? Both the 35R and 40R are great turbo's for the 13B.

-Sean

I'm most concerned about finding a solution to turbo control. How do they do it on the Ford diesels?

This is definitely going to be the hardest part of this project.

From skimming over the Ford 6.0 manual it appears that the vanes are hydraulically actuated from a "high pressure oil system" that is engine driven, though seperate from the standard engine lubricating "low pressure oil system".

There is a small valve that is electronically controlled to vary the oil pressure to the piston that actuates the variable pitch blades.

I hope it is a push/pull arrangment so that there is less chance of it sticking. I think the chances are good based on Garretts earlier experiences w/ the t25 VGT that only used spring and boost pressure (like standard WG actuator) to move the vanes- had a real problem w/ sticking.

I will know when the turbo gets here- I bought the 1st last night.

In the Ford the turbo is in the low backpressure/slow spool position under light cruise conditions and moves to high backpressure/quick spool as soon as you dip into the throttle. I imagine it is very much like the way a car w/ O2 sensor goes from closed loop at cruise to open loop maps w/ some throttle change.

Then as the desired boost is reached the vanes are varied toward the low backpressure position until the boost is stable. No wastegate needed, of course.

I would probably incorporate a "race" switch that when armed would keep the turbo in the quick spool state as long as boost was under max. This would allow for awsome boost response- though fuel mileage and EGTs would suffer.

Could you clarify what limited HP and lag are by your definitions.... since different people want different thing.

In the context I used it needs no clarification since people deciding between the GT35 and GT40 will obviously choose the GT35 in they do not want the added lag of the GT40.

Likewise, those choosing the GT40 will have done so because they felt the GT35 was too limited in HP potential.

The GT37 appears to me to be a middle ground between the GT37 and GT0.

http://cherrypicker.tripod.com//site.../gt-turbos.jpg

The 35R has been shown to make 400-450RWHP and is claimed by "those in the know" to be one of the best spooling turbo's on the market.

Right, so imagine a GT35R that used the VGT exhaust housing. It would spool up MUCH faster and by not requiring a wastegate to bypass exhaust flow at full boost should have greater top end power as well.

Remember the popular GT-R turbos are hybrids made from mixing and matching within the GT family of turbo housings, wheels and CHRA.

It should be possible to use the VGT housing w/ another GT turbo's ball bearing center section and GT40 compressor just as it is possible to make a GT30R that is GT30 exhaust side and ball bearing center and GT37 56 trim compressor section.

If we can adapt VGT exhaust housings it would open up a whole new realm of turbo experimentation w/ the GT line...

I will stick w/ the straight GT37 VGT for now since it is only $300 and the real work is getting the VGT to operate.

There is very little lag on the 40R when compared to the 35R also the 37 is nonBB, the maps you chose for the 35/40 are wrong also.

Maps are probably correct, they are for GT35 and GT40 not the hybrid GT35R and GT40R variants as you are probably thinking of.

For instance a GT30R is GT30 Exhaust side and BB center mated to a GT37 compressor side. GT30 compressor map would look different from GT30R map...

My question is other than taking up the challange of making it work and being a little unique(both good reasons) why? Price? Both the 35R and 40R are great turbo's for the 13B.

Say it with me-

GT37 VGT

VGT is for "Variable Geometry Turbo."

This 1.0 A/R exhaust housing has many robust stainless vanes that can vary their angle to change the effective A/R of the turbo for both incredibly fast spool rate and free flow once desired boost is acheived. No wastegate needed.

The nonBB center of a GT37 VGT is likely going to spool up WAY before a GT35R. If you still want faster spool up I imagine a BB center could be retrofitted as well as a larger compressor side.

Let me just add: to say that the 40R compares favorably with the 35R doesn't mean that both turbos aren't laggy. I think the afformentioned turbos are fine if you commit to keeping the revs up above 3K, but for street driving or autoX those turbos don't have the usable torque band that you'd like.

I'm not trying to start a lag flamewar; I'm just pointing out that the VGT offers the possibility of sub-3K spool (especially in low gears) with the ability to put down more than 400RWHP. It also offers a vastly simplified exhaust system that is immune to creep.

-ch

Well thank you for informing me as I don't think I could have figured that out, admiral obvious, please understand I wasn't getting on you, but since you want to sound like a cock that's fine, the comp. maps shown are wrong. If your knowledge was as vast as you imply you would know that the 35R is the 35/40. I mean I've only been selling both these turbos now for years buying from both overseas and Garrett USA and they are the exact same thing but what would I know. Reminds me of how everybody thought the GT40s in the fords in australia were ball bearing GT40's and truth is the are just 35Rs or 35/40s whichever you choose to call them. Ford just liked the name. The chances of fitting a BB center section are next to none, but good luck and before you go fitting a larger comp wheel on there make sure your compressor to turbine ratio is not going to be too far out of whack either. Now as I said before and maybe this time we should say it together this will be a good challange and very unique both good reasons to do it but no reason to sound like a ass.

True neither of these turbo's are good for autocross a 35R with the .82 spools very quick, ask rallimike about that he has one it feels like a V8, but wont get you over 400whp without raising boost more than most want to, the simplified exhaust side is a plus but at the expense of added comlpexity elsewhere these turbo's are known to stick and didn't do as well as hoped but still are a valid idea.Good luck

-Sean

Ah, I really thought you hadn't grasped that we were talking about the VGT variant of the GT37 here.

When you say the GT35R/40R are some of the best spooling turbos and thought GT37 VGT be simply "unique" and "challenging", but not performance enhancing I thought we were thinking along different lines.

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.

I am a turbo newby, but yes I have read that a GT35R is a hybrid turbo using a GT35 exhaust side, BB cartridge and GT40 compressor side- AKA GT3540.

So GT35R would use GT40 compressor map, right?



Why would it be next to no chance of fitting a BB CHRA to a VGT housing? We he the ability to machine parts.

My current turbo is a BNR stage IV that is T04B 60-1 HiFi compressor side and clipped T04 "P" trim wheel in bored stock '89 exhaust housing using stock center section and adapted to use a 60mm external WG. none of that stuff "bolts together".

Yeah, I've had it off 5 times to modify it to fix boost creep- but that is the learning process.

I do not doubt this VGT process will be even more complicated than a "simple" stock hybrid turbo.

This will be a good challenge and unique...

Now say this with me!

with potential for incredible performance gains. :)


Sorry if I come off like the ass that I am; especially since debates w/ informed members (such as yourself) is the reason I post on this forum.

GT35/40 uses a GT35 compressor and GT40 turbine. Easy to remember when you think that RX-7s like lots of exhaust flow.

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 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 ass maybe we just misunderstood each other so no harm no foul.

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.

Yes I agree the VGT is interesting technology, and may be beneficial. It certainly adds another level of complexity.

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.

Good luck.

-Chris

The 35/40 uses it's own wheel, there is some confusion on this because of people in australia misinforming others and some shops even "made" 35/40s as you described to try and get in on them as they were made in small quantities at that time, so availability was limited and this is/was due to the way garrett does it's production runs, those turbo's weren't bad but weren't as eff. either.

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

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.

Well said certainly better than me, I'm just tired of typing, but you hit it exactly.

-Sean

Here is the correct compressor maps

http://www.atpturbo.com/root/maps/gt35r.htm

http://www.atpturbo.com/root/maps/gt40r.htm

I really hate when I do $@&! like that. Thanks.

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...

-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 ass. That way if I don't mean to be an ass I can let you know; and if I do mean to be an ass I can let you know :D

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?)

bump. Any news/updates on the VGT?

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...

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

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.

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

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. :D

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.

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?

-ch

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.

You are talking about EGT aren't you.

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.

any updates about this turbo?

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.

http://www.teamfc3s.org/forum/attach...&postid=310865

This one shows the VGT hydraulic actuator housing cast into the turbo center.

http://www.teamfc3s.org/forum/attach...&postid=310866

Here are the VGT vanes in the "closed" position or spool-up position.

http://www.teamfc3s.org/forum/attach...&postid=310867

The vanes in "open" position or low restriction position.

http://www.teamfc3s.org/forum/attach...&postid=310868

This shows the "unison ring" that moves the vanes together and provides the front wall of the turbo nozzle.

http://www.teamfc3s.org/forum/attach...&postid=310871

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.

http://www.teamfc3s.org/forum/attach...&postid=310873

The piston/rack

http://www.teamfc3s.org/forum/attach...&postid=310875

The solenoid valve that directs the engine oil.

http://www.teamfc3s.org/forum/attach...&postid=310876

:bigthumb: looks pretty promising if you can get it to work correctly

any thing new?

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

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.

or, if someone has some time and is really creative..............remake them out of something with higher heat tolerances. that would be cool.

any updates?