Turbo Slant Six Dyno - 1st Attempt

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stop the beast

stop the beast

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Hi All,

I've been working on my turbo build for about a year and a half now and finally got some results today.

Slant six + GT32 @ 16.5 psi =

440.6 lbft @ 3808 rpm

and

330.7 Hp @ 4057 rpm

Not too shabby. The reading was from a dynapack at the rear wheels so I'm guessing she's got around 500 lbft on tap at the crank and as much as 400 Hp.

Full thread with the details: http://www.forabodiesonly.com/mopar/showthread.php?t=212272

Dyno plot:

IMAG0034_zps4e01c644.jpg


'66 on the Dynapack:

IMAG0030_zps0151a8b5.jpg
 
Nice, are you planning on going up on the boost anymore? What are your a/f wot. I run a gt35r on a sti and it is amazing what boost does.
 
racerkilla said:
Nice, are you planning on going up on the boost anymore? What are your a/f wot. I run a gt35r on a sti and it is amazing what boost does.
Click to expand...

Actually trying to get the boost down to 15 psi. AF/r on this pass was between 9.5 and 12.7 (12.7 at peak torque), with some slight audible ping. Not good!

I'm running a 500 cfm 2bbl Holley with a boost referenced power valve and 76 jets. I'm going to talk to my carb guy to see if we can open up the flow on the power valve and run a smaller jet. This might help tighten up the disparity in the AF/r across rpms. If I can get that high end AF/r down below 12 I think 16-18 psi would be great.

The reason the boost keeps creeping is because the turbos small internal waste gate, the gt32 was probably meant for a high pressure diesel setup - it's a twin scroll but only one side of the housing sees the waste gate, we might need to open that up as well. I'm going to machine out the exhaust housing and put in a bigger waste gate for starters.

It's going to be a street cruiser for most it's life so I want to strike a good balance. If we can keep the boost at 15 psi we should be to get a safe 400+ lbft and ~325-350+ Hp playing with timing (MSD 6530 w/ MAP sensor).
 
That 66 Dart is a light car, so imagine how that torque will go into acceleration. You now have a true Chrysler 300.
 
Build me one dam .Great job .Just a couple questions hows it feel when you drive it,are you having any over heating issues.and what was the final cost?

Thanks Arco
 
Arco440 said:
Build me one dam .Great job .Just a couple questions hows it feel when you drive it,are you having any over heating issues.and what was the final cost?

Thanks Arco
Click to expand...

It feels ridiculous when I drive it because it doesn't have enough tire. It's hooked a few time and you can feel the 11s et inside. No overheating issues thus far - and I'm running the stock radiator from the original 273 :)

Cost wise, I haven't broken it all out at any time. I figure the cost of the car, suspension, drive train, engine and turbo setup has to be creeping into the $12+K range. The engine and turbo kit we're probably half of that, I set everything up so later on I can swap in a bigger turbo and shoot for the 450whp range...
 
You said the boost creeps up so why not run a external waste gate. I run a tial 44mm external on my sti to stop boost creep
 
Congrats on a job well done !!!
And at last,a picture of the Dart...
Keep us posted as you get it tuned !!!
 
racerkilla said:
You said the boost creeps up so why not run a external waste gate. I run a tial 44mm external on my sti to stop boost creep
Click to expand...

Looking into that this week. The manifold was built so that we could add one if I needed, I need it!
 
Great HP and big time torque and user friendly :cheers:
Turbo is the way to go, Congratulations and thank you for sharing :glasses7:
 
WOW!
Absolutely awesome work. :cool:

This begs the question- what are the limits of the /6? I6 motors can make insane power (like the Toyota Supra)...can an injected /6 be built to keep up? IIRC the stock /6 bottom end is pretty stout....no?

Are they severely RPM limited because of that heavy crank?
 
They are RPM limited because of only having 4 main bearings. And a ridiculously long stroke (by modern standards). A Supra 2JZ-GTE engine with a 86mm stroke can rev safely to 7500+ rpm without hitting piston speed limits. A 225 slant with it's 104.7mm stroke hits the limit at under 6500 rpm.

They are boost limited by having only four smallish head studs per cylinder. They are breathing limited by the non-crossflow head.

There are 650 hp turbo slants around, but not many.

The OP has a very nice setup, well thought out.

MRGTX said:
WOW!
Absolutely awesome work. :cool:

This begs the question- what are the limits of the /6? I6 motors can make insane power (like the Toyota Supra)...can an injected /6 be built to keep up? IIRC the stock /6 bottom end is pretty stout....no?

Are they severely RPM limited because of that heavy crank?
Click to expand...
 
robertob said:
They are RPM limited because of only having 5 main bearings. And a ridiculously long stroke (by modern standards). A Supra 2JZ-GTE engine with a 86mm stroke can rev safely to 7500+ rpm without hitting piston speed limits. A 225 slant with it's 104.7mm stroke hits the limit at under 6500 rpm.

They are boost limited by having only four smallish head studs per cylinder. They are breathing limited by the non-crossflow head.

There are 650 hp turbo slants around, but not many.

The OP has a very nice setup, well thought out.
Click to expand...

Great info, Robert. Thanks!
 
MRGTX said:
Great info, Robert. Thanks!
Click to expand...

BTW, the slant six has four main bearings, not five.

But, those main bearings are exactly the same size as the mains in a 426 Hemi, which has five...

The engineer responsible for designing this engine said, "I don't want one of those long, whippy, 7-main bearing cranks." Or something like that. I got that from Willem Weertman's book about the history of slant six design.

It's a short, stout, forged crank and will withstand lots of boost.
 
Sorry Bill, you're right about the slant having 4 mains. Wasn't thinking, but I was staring at a crank!
 
robertob said:
They are RPM limited because of only having 4 main bearings. And a ridiculously long stroke (by modern standards). A Supra 2JZ-GTE engine with a 86mm stroke can rev safely to 7500+ rpm without hitting piston speed limits. A 225 slant with it's 104.7mm stroke hits the limit at under 6500 rpm.

They are boost limited by having only four smallish head studs per cylinder. They are breathing limited by the non-crossflow head.

There are 650 hp turbo slants around, but not many.

The OP has a very nice setup, well thought out.
Click to expand...

I have to agree here. The /6 head just doesn't flow nearly enough and needs tons of lift to get close to a modern head. They won't spin nearly as fast either.

Hopefully they are as bullet proof as we hope :) I'd hate to see my bottom end in the scrapper.
 
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