running_cold924

well, moving up from the k26-8 to something slightly......larger.....its probably going to be overkill right now on the 2.5 but I want to know if it will help spool...SOOOOO after reading a lot of posts, and seeing that very few, if any, are running the same turbo as myself on the 2.5, I'm hear for some opinions.

I have a journal bearing CHRA (center housing rotating assembly) with a GT35R compressor "wheel" (56 trim) in a T04E compressor housing measuring .60 a/r. The turbine wheel is a Stg 5 in a #8 KKK replica housing.

Well, I believe my 2.5 has enough gasses to keep her spinning but want to keep it easy for it TO be spun. Would a larger downpipe help and if so, how much? I an running the 3 inch exhaust and no cat. No emissions here, just visual. Headwork and maybe a cam in the future, and definetly a clutch which will be hating life soon...

what say ye?

CPR

The GT35's are BIG turbos..........a larger downpipe will help, but you will need a lot more than a DP to maximize that thing.

Supernotch93

Try looking at the GT3071R, I think this turbo is perfect for our cars and shows great spool times. Are you still using stock headers and crossover?

running_cold924

yes, still stock headers and crossover for now...atleast they are not leaking anywhere (that I know of)

Paulyy

a GT3078R .82 A/R is also a decent turbo vor our 2.5

with the turbo you said, you wont see any decent power untill 4500+ rpm

Willard Bridgham 3

The pressure drop from the turbo down-pipe stock" vs 3" is approximately 1psig (from turbo to test-pipe). 3" is what will fit here on relatively stock cars.

Based on 550 cfm turbo.

running_cold924

so basically I am better off using $$ for head mods other than a downpipe...

this right Willard?

also Paulyy, do you really think it will be that late? I guess we'll find out this weekend...

CPR

The money needed for 'proper' headwork will be at least $1500 upto $3500.

IMO, you would be better of sellling this one to the 3L guys and getting a GT30.

running_cold924

CPR, what is your honest opinion of what will happen when I bolt this thing on?

the reason I ask is that I have not really seen any posts of people doing this to a 2.5, but lots have done this to a 2.7-3.x L engine...probably for good reason. Maybe I'm just dumb, but I do this this turbo will work. I have the right tuning (the best IMO, no piggyback yet though) and mostly correct mods to start with...

it will use the #8 hotside (KKK) and it has much newer technology than say an older 60-1hifi or k27...

anybody else running this turbo? I believe Duke is but he has a 3.0 (i think)
feel free to chime in Duke and give me your opinion...

TurboTommy

What will be the size of the turbine wheel in that #8 hot-housing?
This plays a huge part in the characteristics of a turbocharger and yet hardly ever gets mentioned in turbo threads.
A smaller turbine wheel with your big gt35 turbo will actually spool up quicker than you think, but will cost you with a significant increase in back pressure.
Generally an overly sized compressor will extract too much energy from the hot side, and won't give you anything back, or will be a lazy turbocharger, or both. So, I don't know if you're doing this just for kicks.
Headwork, and especially a cam will exagerate the problem further.

A downpipe should obviously be big enough to not hinder the gases coming out of the exducer.

Scott H

What do you use the car for/how much power do you want?

CPR

Based off of the information he has provided the turbo will have:

~turbine inducer diameter= 84
~turbine exducer diameter= 68

To calculate the A/R of the turbine, I would need to know if it is a -1,-2 or -3. They range from 1.06 (-1), .82 (-2) and .63 (-3)








cold,

you don't really have the best 'tuning' because you can't really tune anything...yet. You have a chip and MAF, that in its current state is not capable of being dialed in. With a piggyback, yes.

The problem with this turbo, is you need more of everything to make it run at its optimum range....or settle for the limited RPM range this turbo will be deemed efficient with what you have.

Dave McGrath was running one of these on his 2.5l, but it was heavily modified (extensive headwork, big $$$$ headers, 4" exhaust, LINK G4 standalone ems, TiAl 46mm WG, etc....etc....the list goes on and on).

It seems like you want someone to say it will be fine, but what everyone is telling you is correct. It is NOT ideal for your setup. whether you choose to live with its inadequacies, then that is your choice. But for what you have the GT3071 is a much better fit if you want something a little 'bigger. However for what you have the GT2871 is perfect and supports upto 400hp.

pole position

The turbo is fine....if you don't mind some lag ,all turbos have lag even the 997tt's, just keep on shifting and rev the **** out of it. Send it to FP for a billet wheel upgrade, BIG difference in spool and top end. With that it will spool similar to a Super 61 but with superlative performance in comparison.

Forget about that stoneage KKK housing................there are still vendors who pitch that crap because of "bolt on" lol, 100% inferior to a REAL modern housing.....your choice.

Second, you need to run 50/50 Meth, Aquamist (my choice due the idiotproof failsafe) or AEM, the rest is, eh, kind of homebrew.

Third, crank up the boost to 22-24+, your current Maf should be able to support it, the only way you are going to make power is upping cylinderpressure, that 1bar is sooo oldschool BS I don't know where to even start, another vendor BS gospel, correct tuning is the key...............

044 or Fuelab (my choice) is mandatory

Four inch exhaust and three inch downpipe, Tial WG 46 is also mandatory, stock headers are fine but you should enlarge the crossover.

While it is true that the power in a Otto engine is made in the head but this is where Forced induction comes into play, for all out power, yes head/cam work but for your example not necessary.

The End, do it right or don't do it at all.

Paulyy

correct me if im wrong but:
Duke is running a GT3582R .82 ar on his 3L twin cam & sees boost from 3-3500
and Corleone is running a GT3582 1.02 ar and dosn't see much from 4k
both on e85 and higher comp.

running_cold924

oops, had my facts wrong...I have a journal bearing CHRA with a GT35R compressor wheel (56 trim) in a T04E compressor housing measuring .60 a/r. The turbine wheel is a Stg 5 in a #8 KKK replica housing.

maybe this will help my cause with the right info...