What size turbo for 3800?

[32vMonte]

Got a buddy looking to turbo his gtp but doesn't know where to start for turbo sizing. I know he has ported heads, cam, and different pistons. He wants to make atleast 500-600+ with the turbo.

Right now he has gen5 with a small pulley, intercooled etc. he is looking to step it up this year so if anyone give some input on what ppl are using out there to make XXXwhp then let me hear it.

Was thinking a 7065 t4 with .81a/r might work but maybe too big. that is a china knock off but everyone and there mom in the mustang and lsx world have great results with as far as Reliability and power. It is $299 shipped.

Or maybe a tc6665 with same .81 a/r....$650 shipped.

Would either of those work well?

Click to read more...

 

[1quick]

The one that stattama/zzp sells with the bigger kit is pretty much just a T04e garrett 67mm with a .68 a/r thats what I ran and it will easily make more than 500whp with the right set up, mine made 522 on 17psi

 

[02BlueGT]

What cam? How were the heads ported? Were the exhaust ports opened up (hopefully not much)... Also, what pistons? Non stock pistons on a 3800 would normally make me a thread like this.

 

[1quick]

only way i would ever do pistons is if it were going to be an all out blower car i would mill the heads down and do the high compression je pistons and shoot for 11:1 or more with an intercooler and e85 it would make killer power on a larger size pulley

 

[32vMonte]

To4e....is that a t4 flange?

How would you think that 70mm comp and 65mm turbine would do as far as spool?

If I recall HK has the same turbo as I described but it was a master power t7065 with I believe a .81 a/r. Been a long time but I remember seeing it in person.

 

[32vMonte]

What cam? How were the heads ported? Were the exhaust ports opened up (hopefully not much)... Also, what pistons? Non stock pistons on a 3800 would normally make me a thread like this.

Don't know full details, and he's been running them pistons for years now with the blower. I know prj did almost all the work on the car. Been through about five 4000 dollar transmission in the last few years lol.

 

[1quick]

To4e....is that a t4 flange?

How would you think that 70mm comp and 65mm turbine would do as far as spool?

If I recall HK has the same turbo as I described but it was a master power t7065 with I believe a .81 a/r. Been a long time but I remember seeing it in person.

to4e is a t4 flange, kevin runs a t3 flange turbo and I believe thats how he gets away with the larger wheel and a/r it actually spools up faster than the t67 i ran but that could also be partly due to his cam choice he has more of a tq bottom end grunt cam than what i ran mine was more of a midrange top end power cam

 

[32vMonte]

Hmm wonder how bad the t4 will hurt spool. I know with an ls t3 t4 spool the same with the same a/r and turbine wheel. Only thing is the t3 holds you back at a certain power level in a twin setup. Other than that they come to life the same. Idk about on a 3.8 liter motor tho haha

 

[1quick]

honestly the to4e t67 is the 3800 go to for big power, im sure there are better suited turbos out there it just depends on if its going to be a drag car or a street car as to what would work better, on a street car i would want it to spool faster the t67 would be about the biggest i would run, when i was building a 3800 camaro I bought a precision 7275 but the car had a trans brake to help spool it up at the line

 

[10sec]

I wouldn't run an .81 t4 turbo unless he has a loose converter. Even HKs car takes a little after the line for the turbo to get kicking, probably just as long as a t67 t4 with a .69a/r turbine side. His turbo is probably the best comprimise for size vs spool. If I were to build a 3800, thats what I would use. I'd build mine faster though

 

[SleeperLS]

Been through about five 4000 dollar transmission in the last few years lol.

This is exactly why I got out of the platform. I do not miss that part of it at all. How KJ has a stock trans still blows my mind.

 

[10sec]

Street tires, stock motor, and it's stock but still a trannyman trans.

 

[1quick]

street tires makes alot of difference, but with 500whp it wont be usable on the street with street tires it will infact be dangerous

 

[Turbocharged400sbc]

.82 t3 on the TR

 

[The Broken Regal]

Yea .82 t3 and its a T70, not sure on the exhaust wheel though, maybe P trim?
[MENTION=45]Handsome Jesus[/MENTION] knows all

Besides the cam and all that other jazz, including I have turbo headers, its also the converter stall, when James had them change it from 2750 iirc to now 3k, oh my, what a difference

 

[boostedguy05]

This is exactly why I got out of the platform. I do not miss that part of it at all. How KJ has a stock trans still blows my mind.

Well. I think he has an upgraded input shaft.

 

[32vMonte]

Hmm interesting info guys, sounds like the 70mm could work. After all it is all about the turbine, a/r, and cam when it comes to spool times.

The 7065 comes in a .68 a/r. That should do the trick.

 

[10sec]

Compression has a lot to do with those spool times as well as the converter.

 

[Yaj Yak]

Well. I think he has an upgraded input shaft.

i do

 

[Handsome Jesus]

Higher compression engine will be able to spool a lot more in a shorter period.

As mentioned, HK has a Masterpower T70 with a .83 T3 flange. I think it works fairly well, but I think the compressor is too big for his car. The turbine side gets it going OK, but the car "rubber band"s pretty bad (pull back a rubber band and let it go, that's what it is like once the compressor gets going)

honestly I think everyone goes too big with turbos lately, where there are gains to be had when running a smaller compressor wheel more efficiently. The new 62 wheels are efficient and light weight, so they should come on faster and deliver plenty of power. I think a 60-62mm turbo on E85 will make your goals and spool like a beast. Run the boost way up high, have a decent intercooler, and it'll make big power.

the real thing to do is buy a RWD car. I went into the 10s with a 58mm compressor and a .63 GN housing (smaller than T3). Meth injection (100%, no water BS) and 93.

 

[jdredd]

the mutt stattama T4 T67 worked out pretty well.. I could have pushed it
over 600whp on stock lowers. Was probably in the 570+ range and was not
maxed out on it yet. Still had a few psi a go.

 

[1quick]

I did notice a considerable difference going from a l26 to a l67 in spool time the l67 felt like a dog from a roll unless you held 2nd gear to keep the rpm higher, then once it spooled up it pulled hard but it wasn't building full boost till over 4000 rpm

 

[10sec]

That's because of the T67, the PT61 spooled in 1/3 of the time. I had both on the l26 and I noticed a lag with the T67.

 

[10sec]

The 61 spooled so fast there was zero need to stall spool it. The one time I took it to the track it was a (forget the term) floor it from a stop, no spool = .1.71 60'

As DD said, the right turbo sizing with your setup is everything.

 

[twinv6gtp]

GTX3076 (not the regular GT3076)

Amazing street turbo. Instant spool, good power. Able to make a lot of boost on a stock engine.

Loved it.

My 500$ parts car (with TD turbo kit) with small slicks went 11.0 @ 126mph with it with weight reduction. My heavier daily driver 2007 GP GT went 12.0 @ 117 mph at lower boost on the pump gas tune.