tony s

hello , finishing my 2.6lt ,102mm 8.3cr pistons , looking for the best turbo combo, not mush info on 2.6 motors here, some research in the web put me on the side of the gt3076r turbo, but I want to know the .63 vs .82 housing pros and cons?
thanks

Scott H

Only difference is spool and top end HP potential. If it's going to be strictly a track car: .82, if going to be a street/autox car: .63. The trade off will be 500-700rpm in spool and 15-20HP up top depending on what else has been done to your car. A GT30R works well enough on 2.5s that the increase of .1L will really be inconsequential in terms of turbo selection. Are you aware of all the issues with fitting a true Garrett GT turbo?

tony s

yes, I like to fabricate and welding, Im doing some chromo an stainless welding right now on the car. want to know if the extra 1L and the little increase in CR can be helpfully in any way in favor of the .82A/R for a street and solo one car

Paulyy

it may help around 100-200 rpm of spool.

I'm in the middle of putting together my 951 with a gtx3076r with a .82 a/r on it

If you're looking for actual numbers, it's going to be hard to get because theres only a few running these turbos and all of them have .63 housings and only patrick (333pg33) has a .82 housing but his got a cam on his which will change how the turbo spools.

333pg333

How come yours is 2.6L? That's usually a size for certain race classes in the U.S. and if I read correctly yours is a street car with some DEs?

I have run both turbos on my car, however to be fair this wasn't the only change when I went from .63 to .82 housing. Also went from a 3" exhaust to a 3.5"-5" exhaust and a pretty big cam. As an educated guess based on these changes, if I was deciding between them both for a street/DE car, I would probably go for the smaller .63 housing. Again this really depends on how you drive and what sort of roads / track you frequent. The .63 spooled up very nicely and early. Pulled all the way to redline but probably flattened off in the higher rpms range. I wouldn't say it 'dropped off' like the k26/6 or k26/8 though. The .83 'feels' like it spools later but really it's too hard to say by just how much as the other changes had a big effect on the motor.

I would also add, just like most turbochargers, these GT products would benefit from increasing the VE of the engine. If anything, a stock inlet, head, headers just feel like a blocked nose when you have a bad headcold. Trouble breathing. Just like this, they feel like they run out of breath. (The stock components, not the GT turbos). On the dyno we found that by increasing boost from 18psi to 23psi didn't yield much change in the upper rpms. More mid range hp, sure, but up top maybe 15whp with a 5psi increase. Could have been other components too of course.

Let us know how you go.

Paulyy, I will be interested how you go with your conversion. That's quite a lot of turbo for a stock 2.5L, are you changing cam or exhaust?

Paulyy

Tony, if you're going to do a GT30R install, please do a build thread, i myself would be interested how you will go through this route.


Pat, well i'm in the middle of mouting the turbo, we've made a 3" turbo back exhaust for this turbo, i have been thinking of getting a cam with a good amount of overlap to work better when the turbo is making the power but haven't really thought about it much yet, probably get some more VE out of the head before i do a cam.
I read somewhere you've running or thinking about an N/A cam? or is it custom?

333pg333

No mine is a custom cam. JET951 / Sean had an n/a cam in his 2.5L, now he's got stock cam/s in the 3L S2 turbo build. I don't think there is a hell of a lot of difference between stock and n/a cams to be honest Paulyy whereas mine definitely shifts things across to the right. If I were you I'd try the stock one first, then maybe an n/a one just because you could pick one up cheap. Then decide if you want to go bigger. I don't think it will necessarily suit your build to go a big cam...for now anyway. That turbo will shift things across to the right as it is. With a fairly stock weight car I wouldn't go too radical just yet. imho.

Paulyy

Ohh,, well the plan is to get it running with the stock 2.5 on 7 psi then get it running on rogues M tune with e85 hopfully and see how it goes.
IICR the N/A cam had extra (i think) 3 degrees duration on the exhaust lobe.

333pg333

That sounds about right re the cam.

Have you rebuilt your motor with new pistons/rings? Why the 7psi?

Paulyy

well funny story, PO asumed there was guru chips in the dme and it was written on the tuning notes with the afm link for my car but then later noticed huntly chips in the dme when i opend it to have a look(not worried though was gona change them to run e85 in the end). so not knowing much about the huntly chips ill be running stock injectors on 7psi(wg spring) maybe 10psi if the afrs are good at redline untill i sort out the next chip set,I

Thom

Patrick, what turbine housing size will be you running on the 3L?
Staying with 0.82 or going to 1.06?

333pg333

Thom, currently there is a BW S362 w T3 on it but I will have the Garrett turbo available should we decide to change. I'd be inclined to change to a 1.06 housing then.

Scott H

Mmmm those BW turbos are niiiiice. Really affordable too. If I wasn't getting my K26 reworked I would have picked up an S256, still may down the road. Does it need any special attention to the turbo mount or does it fit on there like any old T3/T4 hybrid?

333pg333

Yes the mount needed to be modified to create some extra room for the hotside.
See before and after pics:

Chris White

Look into the Tial hot sides for the GT series – much better fitment on the 944! Plus that are really nicely made.