Poll: 76mm Turbo or Heads/Intake?

[sosoe]

Damn must be nice to chunk cash around from a 6.0 coupe to a soon to be turbo coupe... I'm in the wrong business..

Also good luck with it if you do go turbo. That set up now has a lot in it. Throw some good heads on it...and spray it! Lol

[turbostang]

I didn't read all of the posts since my first one - other than, Sam, I have to say I respectfully disagree.

That turbo (S400) is a GOOD turbo for THIS application, but - There's tradeoffs between it and a MPT76 of the T4 variety.

Major tradeoff - size, obviously, the S400 is a lot bigger and requires the 5" downpipe. The T4 MPT76 using the smaller downpipe etc.

The problem is that, yes - the make good power with low boost for a reason. The LS engines make decent power withOUT the turbo, so they make good power with 'low' boost. Next, you get tired of that same power, and turn it up - and it runs out of steam FAST. Even with the safest of tunes, the backpressure in the turbine kills headgaskets in short order, or at the very least, jacks the tune to hell and back.

The S400 uses a 'different kind' of turbine wheel - not sure what's the exact difference, but even with the big wheel, it comes in fast - we're only launching around 3700-3900 and it's all in under 1 second. Has ran a best of 5.42@130 or so a couple years back...

The other example was a precision PT76GTSH, a top of the line T4 turbo - 'only went 5.80's' a long time ago and only went 123mph. It lost everything over 18psi or so...Now, it's much easier to package, but loses a LOT of power and NO upgradeability.

both cars, very similar engine and trans - but the turbo was the major difference.

I guess long story short, low boost big power is ok - but you WILL run out of steam QUICK. With a T6 turbo, you can upgrade the turbo without hacking the kit up or starting over.

Now in James' car, It may not be an option with the accessories on it now. IDK.

[dville_gt]

I didn't read all of the posts since my first one - other than, Sam, I have to say I respectfully disagree.

That turbo (S400) is a GOOD turbo for THIS application, but - There's tradeoffs between it and a MPT76 of the T4 variety.

Major tradeoff - size, obviously, the S400 is a lot bigger and requires the 5" downpipe. The T4 MPT76 using the smaller downpipe etc.

The problem is that, yes - the make good power with low boost for a reason. The LS engines make decent power withOUT the turbo, so they make good power with 'low' boost. Next, you get tired of that same power, and turn it up - and it runs out of steam FAST. Even with the safest of tunes, the backpressure in the turbine kills headgaskets in short order, or at the very least, jacks the tune to hell and back.

The S400 uses a 'different kind' of turbine wheel - not sure what's the exact difference, but even with the big wheel, it comes in fast - we're only launching around 3700-3900 and it's all in under 1 second. Has ran a best of 5.42@130 or so a couple years back...

The other example was a precision PT76GTSH, a top of the line T4 turbo - 'only went 5.80's' a long time ago and only went 123mph. It lost everything over 18psi or so...Now, it's much easier to package, but loses a LOT of power and NO upgradeability.

both cars, very similar engine and trans - but the turbo was the major difference.

I guess long story short, low boost big power is ok - but you WILL run out of steam QUICK. With a T6 turbo, you can upgrade the turbo without hacking the kit up or starting over.

Now in James' car, It may not be an option with the accessories on it now. IDK.

Just when my choice started seeming much more simple

It'd be a lot easier if the S400 wasn't the same damn price as the MPT76! I know everyone has had good luck with the MP, but I can't help but feel (based on what I've read) that the Borg Warner unit is a higher quality piece. Only issue I see (based on the compressor map) is that I it is going to want more boost pressure then my stocker will want.

Since I am building the kit from scratch I think I can get away with either a T4 or a T6 setup.

T76

S400


Both of these are assuming I'd need around 10psi for 650fwhp

[dville_gt]

Also, Brooks, what do you make of the 1.32ar exhaust housing on the S400-75?

[turbostang]

Also, Brooks, what do you make of the 1.32ar exhaust housing on the S400-75?

I think that's overkill and it would definitely be a dog below 5k. I'd be looking for the 1.0x or .96.

[2165 Turbo Rail]

now that I can more understand doing (putting the .96 on the S400)

[dville_gt]

I think that's overkill and it would definitely be a dog below 5k. I'd be looking for the 1.0x or .96.

well the 1.10 is the same price as the 1.32. b/w doesn't make a s400 with anything lower then 1.10 turbine housing.

[F8LSVT]

I would do the h/c/i now and the rest later. That way you're that much more ahead when you decide to boost it.

[2165 Turbo Rail]

Doing h/c/I now would be a waste if boosting later. Yes it would help a little but you don't want the same cam so that would be a waste and the heads and intake as way less important on a forced induction motor

[War Machine]

I say spray the piss out of it, fuck all this shit. get some big shot solenoids, take the fucking jets out (jets are for people who dont know what the fuck theyre doing,) and add fuel til it's fucking busting out low 5's and shit

[DallasGT01]

for your level is the on3 70mm out of the question? looking at some of the cars its on they seem to be in the 550-600rwhp area.. i thought...

[turbos66coupe]

You have to decide what your goal is and stick to it. I'm sure brooks can agree to this. The s400-475is going to be a big power turbo and will shortly turn that car into a track only car. The hales speed shop guys will tell you they don't have "race cars" they are show/street cars that are also fast. If you want it to be more cost effective and keep it driveable go with mp76 and don't look back. If you go with the s400 I predict you will find your self relocating the radiator, putting a a/w intercooler in the passenger eat, and pulling your hair out

[Magnimike1]

You have to decide what your goal is and stick to it. I'm sure brooks can agree to this. The s400-475is going to be a big power turbo and will shortly turn that car into a track only car. The hales speed shop guys will tell you they don't have "race cars" they are show/street cars that are also fast. If you want it to be more cost effective and keep it driveable go with mp76 and don't look back. If you go with the s400 I predict you will find your self relocating the radiator, putting a a/w intercooler in the passenger eat, and pulling your hair out

Totally agree

[Dan03mach]

Garrett GT4276 would also be a very good turbo for your application. I'm putting one on my car and should make plenty of power.

[Z06killinsbf]

If you get the Chinese brand, go big. They are known to run on the small side of what they are advertised at. Theturboforum has a whole write up on them and if you get the right manufacturer, you can get a good one. It is a gamble yes but I've seen people have good luck out of them.