no4njnk

Right now I have a 72mm turbo and I am going to have it rebuilt/freshened up. To freshen it up it will cost me around $200 to have it rebuilt and balanced. Or I can pay around $1000 to get it upgraded to an 88mm.
Most likely I will be using a 68-72 block for this. The rest of the combo is Vic Jr heads, ported GT40 lower and Downs upper. I want to be able to push the limits of the stock block.

__________________
Kyle-94 Black Lightning
Nitrous is like hot girl with with STD's.
You know you wanna hit it, but your afraid of the consequences

FMOS Racing

I don't think the 72 will get you there, an 88 will go waaaaay beyond.

no4njnk

My thoughts is the 88 may take me too far beyound. With the prices of GT42-76s right now its hard to pass those up.

FMOS Racing

76s are da pimp juice for a factory block, IMHO.

I Tried

With the right combo 76mm should blow the crank right out of the block. Im hopeing to make around 800 rear wheel with 1.

FMOS Racing

Gotta run a 76 pretty dang hard to get 800 rwhp out of it.

no4njnk

I may just run this 72mm and see how it will do. They are rated to 850 flywheel and the car will be under 3000 lbs so I may hit 9s. The thing already has a T6 flange so why not.

Right now it has a 1.32 compressor housing, should I try and find the other one which is a .96 A/R?

I Tried

I should know in 3-4 months when my truck is ready to chassis dyno. My 392 stroker made 576hp on a engine dyno with 9.0-1 compression turbo grind cam and a carb.I plan to put 20+psi to it. And if that doesn't do it, time for the N02. I hope to run mid to low 10's at around 4k race weight and feel that it will take around that hp level to do it.

Turbodiesel

I would upgrade to an 88 or go with a GT42-76 with a T6 flange. I just go mine for forcedinductions.com, and the GT42 is a nice piece. Not bad on price either.

I Tried

? If it will be hard to make 800 rear wheel hp with a 76mm turbo how do the gen2 and cobra guys do it? I installed a hellion kit for a friend on a completely stock 03 cobra cams and all stock took his KB blower off and installed 99 cobra intake and out of the box on pump gas it made 833 at the wheels on pump gas and 15psi with 281 cubes?

ugotstrk

I think it has to do with cylinder head flow, rpms,and having a motor and cam(s) designed for boost. 16 lbs isnt a big deal on a gen 2 or cobra. On a gen 1 (stock internals) its more of a deal. Also gen 1 figure 19% or more parasitic losses whereas cobras are closer to 11% losses. So gen 1 needs 950 or better to hit 800 at the wheels. So pushing a gen 1 to those numbers (950+) can be tricky even with studs, girdles, etc. I will find out soon though how long they will live at these power levels, courtesy of Icepick BOOST WITHOUT BELTS!

I Tried

My motor should be good. I have a sportsman block with splayed 4 bolt main caps, Ross forged pistons, Oliver Billet rods and a forged steel crank. All balanced and 9.0:1 compression. I have a cammotion custom turbo cam, I have trick flow twisted heads that are ported and polished that flow 322 at 650"lift. I dont rember exhaust but it was in the low 250's. I have a hard time beleiving that the gen 2 heads flow better than that.

no4njnk

Its not only about flow, mod engines have less turbulance and better airflow than a pushrod engine. And I hope the exhaust on the heads is more like 250, cause our stock Vic Jr heads flow 245 on the exhaust.
With what you are doing I would go with something with a big T6 frame, like an 88mm or larger. By the time you throw nitrous on there you could have gone cheaper and gone with a bigger turbo.

FMOS Racing

Umm - 833 to the wheels at 15 psi???? Basically you're saying that that motor would be making 450 or so to the wheels unboosted...

I don't know of any Gen 2s making that kind of power on a 76....

And I agree, with that block, don't fart around with a "little" T4. Put at least a T88 on it. And you may want to consider a T91.