My GT40R came in today. It looks nice with the HKS exhaust manifold
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It's a pretty sweet manifold. The runner design looks crazy
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Only thing is... the mani is not 100% divided like the turbo housing is
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Theres about a 3/8"-1/2" gap
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The wastegate flange isnt totally divided either
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Does anybody think that it might be better to get a single scroll Turbine housing with this mani?
I like how the runners come down and channel right into the divided turbine housing. Thats pretty good.
I thought about having a metal wall welded in to fill in the division but the WG still won't be divided.

I have a good feeling this will at-least work as good as a single scroll.
It'll be interesting to see how this combination performs with stock internal motor, stock intake mani, & stock redline.
500whp on pump gas????? We shall seeeee

Nice set-up, very interesting to see that turbo on stock every thing

I weary of running this turbo the way you want to, stock motor/intake/mani. From my experience, on a true divided tubular manifold, and a 2.3 stroker, we saw full boost around 5k. With that said, I would expect you to make full boost round 6k. Leaving about 1k rpm of power before you have to shift. Plus stock cams are not gonna help at all. Give it a try though, you never know.

Edit: Your profile says you have a built head, so I guess you're not 100% stock motor.

No, it's not a 100% stock motor. I wouldnt say its stock everything either fwdmaster. My car is far from stock.

I call the motor a stock internal motor. Maybe I should say OEM internal motor?
Its rebuilt with 1G big rods, & 2G 8.5 compression pistons. Mitsu rod bolts, and ARP head studs. The head has no work done to it. It has dual springs, and FP2x cams.

When going through gears I shift @ 7000RPM, but when I run the 1/4ml I have to rev to about 8000RPM ...crossing the traps at the top of 4th gear. The main factor is that I will be using the stock intake manifold, so that'll kill the upper power band.

I sure hope I don't get full boost @ 6000RPM, but maybe.
Looking at twicks69 Dyno sheet... he hits 20psi by 4050RPM, and 30psi by 4150RPM. I'm bet thats in 4th gear, but pretty damn good anyways. A 2.3 or 2.4 usually reaches full boost about 400-600RPM sooner than a 2L. With my FP3065 I easily hit 20psi by 4100RPM. I'm fairly certain I'll hit 20psi by 5500RPM with the 40R. I even think there's a good chance I can do it by 5000RPM

When I had the FP3065 I was only running a ported EVO3 manifold. The HKS will flow better, and in turn spool the turbo faster. I think we'll all be surprised at how good this turbo works. Maybe my findings will raise the "Streetable-Turbo" bar again?

unlmtdndeavor said:

I weary of running this turbo the way you want to, stock motor/intake/mani. From my experience, on a true divided tubular manifold, and a 2.3 stroker, we saw full boost around 5k. With that said, I would expect you to make full boost round 6k. Leaving about 1k rpm of power before you have to shift. Plus stock cams are not gonna help at all. Give it a try though, you never know.

Edit: Your profile says you have a built head, so I guess you're not 100% stock motor.

Click to expand...

Twicks69 sees 40+ psi WAY earlier than that with his true divided runner manifold and 4088r with a 2.3 stroker.

Yeap

I believe what unlmtdndeavor said was true but the lag could be due to tune and alot of other things.
According to Twicks Dyno sheet he hit 40psi by 4600RPM


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http://www.dsmtuners.com/forums/drag-strip/273585-re-dynod-eclipse-740awhp-696tq.html
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Thats with the .96 A/R Turbine housing too
I have the .85 A/R housing which should spool a tid bit faster, but we'll see ....cause my combo isnt 100% divided.

It is possible. But he has altered his timing curve to allow for this. Plus there's always nitrous!

Didn't you read our suggestions in the 4088 thread I started a couple days ago? I'm not sure why you are hesitant to sell the manifold you have to get a true divided setup when it should only set you back a couple of hundred dollars extra. Since you don't have the extra displacement twicks and I have you are really gonna need all the help you can get with spool and driveability using such a large turbo. It will probably cost you more money to bastardize your brand new billy-badass 4088 turbo by switching to a slow spooling inefficient open tang hotside than it would to just sell your mani and buy a divided t4. Don't get me wrong, single scroll hotsides are tried and true to make big power but there is a reason why that nice new 1700 dollar 4088 turbo came with a divided hotside. If you dont believe me and dsm-onster then call geoff at full-race.com (he probably knows more about turbos than most people on the planet) and ask him about twin scroll vs single scroll manifold and turbine housings, volumetric efficiency, and dividing exhaust pulses to maximize performance. Like I said before in the other 4088 thread... it's your car, do what you want, but when you get that turbo setup put on and it performs like crap because it's not divided properly some of us might be tempted to chime in and say "I told you so".

unlmtdndeavor said:

It is possible. But he has altered his timing curve to allow for this. Plus there's always nitrous!

Click to expand...

No nitrous for his 40+ psi at 4200rpms . He still has a flat 700whp horsepower curve. So I don't think the timing curve was altered in a way to hinder anything. It is what it is.

As long as there is no predetonation, any motor can handle any amount of cylinder pressure. Your OEM bottom end build should be able to handle the GT40 w/o problem as long as you can tune, or use cool enough burning gas to compensate for increased boost pressures.

dont trip about the small space left by the HKS manifold... it is less than ideal, yes... it dosent make that big a of a diff... I run that manifold with a divided T67 and I love it.

Take the turbine housing off and port it to make the separation wall more narrow.

dsm-onster said:

No nitrous for his 40+ psi at 4200rpms . He still has a flat 700whp horsepower curve. So I don't think the timing curve was altered in a way to hinder anything. It is what it is.

Click to expand...

That specific dyno graph and tune was NOT running an altered (retarded low rpm ignition timing to increase spoolup) timing map. That was just a standard street tune. We were able to pull another 400rpms faster spoolup with a moderately retarded ignition timing map in the spoolup rpms. I don't have copies of the dyno graphs on my PC -- they are still on the shop's computer. The downfall to doing a heavily retarded ignition ramp-up map is that it puts a heck of alot more heat into the turbo and exhaust manifold, and you will wear your turbo out faster. To be on the safe side, 4000-4500rpms is definitely obtainable with a solid tune on a GT4088R/2.3L setup -- without nitrous.

Boosted98gsx said:

As long as there is no predetonation, any motor can handle any amount of cylinder pressure. Your OEM bottom end build should be able to handle the GT40 w/o problem as long as you can tune, or use cool enough burning gas to compensate for increased boost pressures.

Click to expand...

Any motor can handle the pressure == it is also a matter of how long it can handle this kind of pressure. ARP head studs are a must. I switched over to ARP L19 studs this season because the head was lifting at 45-50psi. Before this though, there were no problems for a long time running standard 2G 11mm ARP head studs and a Mitsu MLS head gasket, torqued to 96-100 lb/ft, and torque checked regularly (50 miles, 100 miles, 1000 miles, 3000 miles, etc.) to make sure it was dead on. Usually it only needed to be retorqued after the 50-100 miles, and every few thousand miles -- I would usually check around 4 times a year.

Use good gas, have a good tune, and make sure that your cylinder head and block sealing surfaces are perfect -- DO NOT use copper spray on the head gasket, and ONLY use a new gasket when you ever pull the head off of the block. It is not worth the risk of reusing a head gasket to have it fail on you later.


Also, my best power numbers to date have been a toss up between VP Import and VP Q16 race fuel. The Q16 is an oxygenated version of C16, and makes nearly the same amount of power as VP Import for the price of C16. That is the difference between $26/gallon (VP Import), and $15/gallon (VP Q16 and VP C16). Anything above 29psi, I would be running a fuel like VP Q16. Between 22-29psi, I would be running a fuel like Turbo Blue (110 octane leaded), or Rockett 111 (111 octane leaded).

VP Q16 as dyno'd to 740awhp on the old setup that I ran until June 2008 at 49psi peak boost; and it made 751awhp on the new setup in the end of June at 42psi peak boost. Unfortunately, the turbo was on its way out during the last event, so 800awhp was not obtained due to boost dropoff. The center section later failed due to the continuous thrashing running 42-50psi for so long.

Stapl3 said:

Take the turbine housing off and port it to make the separation wall more narrow.

Click to expand...

I would not touch the turbine housing at all.