Twin Turbo LS1 1993 RX7 Build

[digitalsolo]

Hey all,

This is a a build I'm working on for/with a friend (The Beast here on 'Tech).

370" Iron block, Diamond forged boost pistons, compstar rods, eagle crank, lingenfelter heads and JPH cam. Built T56, McLeod twin disk clutch and Mustang Cobra 8.8 IRS rear.

Here are a few pics of the progress so far; the turbos are twin precision 60 mm units:













The piping is schedule 10 stainless 2.5" for the feeds, with 3" outlets from each turbo merging into a 4" downpipe. The 4" downpipe will eventually neck down to 3.5" with a bullet muffler and dump under the car.

Comments?

[LS1RedZ]

Thats gonna be nasty in that light of a car!

[Skillet]

You are going to need both hands and then some to wrestle with that thing. What are you shooting for? Keep us posted.

[Pat-Man]

Damn! Very impressive.

[digitalsolo]

His goal is 1000.1 RWHP on race gas/meth just for a Supra style dyno queen session. Normal tune/setup will be around ~750 RWHP pump gas + methanol. The setup should be good for it, though the devil is in the details, so we'll have to see.

Fueling is twin Supra Denso fuel pumps, modified for higher flow/voltage, in tank, with -10 feed to Summit fuel rails to regulator -8 return. Injectors are (I think) 80 lbs units (90 lbs at 58 psi) and the fuel system will be boost referenced. Control will be a 99+ PCM w/ custom OS. Probably be taking it up to Speed, Inc. for tuning once it's broken in, I will do the base tune myself.

Here are a couple of earlier pics:





Interior:



Body is rough right now, but is straight and rust free. Will be getting a new paint job once the drivetrain is complete and sorted. Until then, it's pink (etching primer).





Engine:

[IT_SS]

(Mazda chassis + Ford 8.8 IRS) Twin 60mm's) + 370 LS1 = a muthin fu(kin' problem!!! that thing is going to be a beast! Are you (or your friend) going to stick it out with a T56?

[digitalsolo]

He's planning on keeping the T56, yes. This isn't a max effort drag car, just a fun street car to play with, so the T56 is the more entertaining (if lower performing) option.

FWIW, I run a T56 in my turbo LS1/RX7 also. Sucks at the track, but it's a lot of fun to drive. Both cars will eventually get Lingenfelter 2 step systems.

[lt170chevelle]

looks like one fun project fro the street

[IT_SS]

whats the weight difference between the iron block and the alum. block ?

[The Beast]

Thanks for the kind words guys

I've got to give a HUGE thanks to Mr. Digitalsolo for all of his time, effort, knowledge, and skill! The swap and the turbo kit wouldn't have been possible with out him

And also for him putting up with me

[digitalsolo]

Originally Posted by IT_SS

whats the weight difference between the iron block and the alum. block ?

Between 100 and 120 lbs depending on whom you ask.

This car will probably be around 52.5-53% front weight distribution due to the iron block + turbos and plumbing. Total vehicle weight likely in the 3000-3100 lbs range (it shouldn't exceed 3100 lbs).

Thanks for the props Nick. It's fun working on the car, plus I get fed well over at your place.

[TiAL]

you're going to need some better priority on those wastegates or you are going to have boost creep

[BlwnLs1GTO]

I wish I would''ve pulled the trigger on an LS swap in my FD. Good for you guys!
I took the money and put it in my 10,000 lb. GTO instead.

I'm curious about welding the SS to Iron manifolds. I did'nt even know that was possible. How are you welding it and what filler material are you using?

Great job on the build

[Brakemotive]

Originally Posted by BlwnLs1GTO

I'm curious about welding the SS to Iron manifolds. I did'nt even know that was possible. How are you welding it and what filler material are you using?

I was wondering the same thing...

[digitalsolo]

Originally Posted by TiAL

you're going to need some better priority on those wastegates or you are going to have boost creep

There is 76 mm (3") of wastegate open to atmosphere, I really don't think the angle of attack of the piping is going to matter too much on it. My angle on my single 48 mm kept me at 7 lbs without issue, and it was no better than that. We shall see how it goes though. The car will be running 10 psi on the base, and there really just isn't anywhere better to put them due to all the other things that must still fit in there. I realize you should be familiar with the wastegates though.

Originally Posted by BlwnLs1GTO

I wish I would''ve pulled the trigger on an LS swap in my FD. Good for you guys!
I took the money and put it in my 10,000 lb. GTO instead.

I'm curious about welding the SS to Iron manifolds. I did'nt even know that was possible. How are you welding it and what filler material are you using?

Great job on the build

Originally Posted by Brakemotive

I was wondering the same thing...

That isn't a cast iron manifold, that's a dual wall SS '98 F-Body manifold. The passenger manifold is C6, and uses a flange to connect to the turbo system. I don't know what alloy GM uses, but it gets ugly with heat. If you look at the second picture from the bottom, you can see the weld between the halves of the manifold, and where we ground off GM's weld where the AIR pipe used to be.

[Brakemotive]

Originally Posted by digitalsolo

There is 76 mm (3") of wastegate open to atmosphere, I really don't think the angle of attack of the piping is going to matter too much on it. My angle on my single 48 mm kept me at 7 lbs without issue, and it was no better than that. We shall see how it goes though. The car will be running 10 psi on the base, and there really just isn't anywhere better to put them due to all the other things that must still fit in there. I realize you should be familiar with the wastegates though.





That isn't a cast iron manifold, that's a dual wall SS '98 F-Body manifold. The passenger manifold is C6, and uses a flange to connect to the turbo system. I don't know what alloy GM uses, but it gets ugly with heat. If you look at the second picture from the bottom, you can see the weld between the halves of the manifold, and where we ground off GM's weld where the AIR pipe used to be.

Gotcha... Nice work! Looks like it'll be a hell of a ride!

[digitalsolo]

Thanks. The hot side should be TIG'd next week and coated soon after that. The cold side is intentionally very simple (and short), and will feed a 2 into 1 I/C with a Vette style center feed to the T/B.

Hopefully all works as well as it should on paper; I really do think the gates will be okay, but if all else fails, well make a few adjustments.

[Kyro-2]

looks familiar!

[digitalsolo]

Originally Posted by Kyro-2

looks familiar!

Yup.

There really isn't another nice, clean way to route the downpipes that I've found as of yet. Speed, Inc. does nice work.

[6techniques]

I love FD's...Lightweight + FI LS1 = Holy S!%T!!!