Pushing a 4.1!!

[castrolgreen]

Hey guys I have a 291 4.1 sitting around with .40 over hyper pistons stock ported heads stock crank 204/214 cam.i wanna push the heck out of it what's the biggest I could go with the turbo even if I have to swap out for a bigger cam

 

[castrolgreen]

Hey guys I have a 291 4.1 sitting around with .40 over hyper pistons stock ported heads stock crank 204/214 cam.i wanna push the heck out of it what's the biggest I could go with the turbo even if I have to swap out for a bigger cam

Basically a full rebuild on the engine with less than a 100 miles on it

 

[Nick Micale]

One of my cars has a production 4.1 cars and a 70mm turbo, and I have run many 9 sec. passes with it at 7000 RPM. My street 4.1 has a TE-45A and is an easy low 10 sec. ride.

I would not trust any hyper piston in a turbo engine, especially a 0.040" over build.

It may be ok on the street with moderate RPM, but the hypers are not a turbo piston, and the ones I have experience with the dish is not correct, so you must account and adjust for a decent compression ratio to obtain optimum performance.

As far as the cam, I would use it with the iron heads as it should have good low end performance. With alum heads I would use a 224/224 cam, and not an exhaust biased one.

 

[SHADOWII]

If you haven't done so, check w/fullthrottlespeed. Mike has some options there, including a stroker kit if you have a mind for it. But like Nick stated, the hyper's are the weak link w/barrowed time.

 

[forzfed]

Don't risk using the hypers!

 

[novaderrik]

just copy this: what's the worst that could happen?

 

[robzombie]

just copy this: what's the worst that could happen?

Why go through all that trouble and use such small turbos!!

That intake design is pretty lame also unless there is something special done to it inside to distribute the air properly.

 

[turbofabricator]

Why go through all that trouble and use such small turbos!!

That intake design is pretty lame also unless there is something special done to it inside to distribute the air properly.

Uhhhmmmmm...........have you never heard of Marcella Manifolds? (note the "M" sticker)
You must be new. . (Just ribbin'ya)
Seriously, John builds some of the very best manifolds on the face of the earth. I have fabricated a hand full in my 40 years of building race engines, and when I look at the quality of a Marcella manifold I hang my head in shame. I have built 5,000+ HP gasoline race engines, too. Very proud of them. His stuff is equal to Michael Angelo in the fabrication world.
Here is a thread to prove my point:
http://www.yellowbullet.com/forum/showthread.php?t=127750
Notice the Dart/Buick cast manifold he built. If you have built some, please show your work. I would love to see it. I might learn something. The older I get and the more I learn..........the dumber I feel.

 

[Undercover87T]

Hyper pistons and "push the heck out of it" don't go together. They are not designed to handle boost or detonation. My old 4.1 had .030 hypers, stock crank/rods, 212/212, 6262 and ported irons. I ran it between 19 and 23psi and spooled quick on the street and put a few passes on it but the tune was always conservative. Now that motor has been rebuilt to .040 or 4in bore with a forged stroker kit from Full Throttle to yield 274ci with a GN1 crank, Molnar rods, and custom Diamond pistons.

 

[robzombie]

Uhhhmmmmm...........have you never heard of Marcella Manifolds? (note the "M" sticker)
You must be new. . (Just ribbin'ya)
Seriously, John builds some of the very best manifolds on the face of the earth. I have fabricated a hand full in my 40 years of building race engines, and when I look at the quality of a Marcella manifold I hang my head in shame. I have built 5,000+ HP gasoline race engines, too. Very proud of them. His stuff is equal to Michael Angelo in the fabrication world.
Here is a thread to prove my point:
http://www.yellowbullet.com/forum/showthread.php?t=127750
Notice the Dart/Buick cast manifold he built. If you have built some, please show your work. I would love to see it. I might learn something. The older I get and the more I learn..........the dumber I feel.

I was half kidding and half serious with that post, Looking at the manifold design it looks like it's just forcing the air charge at each other [like hitting a brick wall] hence my comment on it better have something inside that is redirecting the air charge.

The turbo comment was me just being sarcastic.