Rafedial

iTrader: (7)

how important is it that the exhaust system before the turbocharger is completely sealed?

What I mean is can the boost pressure be limited by a small leak in the hot side? I am only seeing 12 psi, WG set up for 18psi.

The exhaust from the manifolds back to the turbo inlet is only 2 pieces, the rest fully MIG welded and pressure tested. Could this one small connection, which has a SS band clamp (good kind), be leaking enough to prevent full boost. It is leaking Fyi. easily visible from black smoke.

The turbocharger is an HX-35 Holset from a Cummins,the wastegate a 40 mm Synapse (small valve seat, 60lb/in spring, ports A+D direct from boost source), the engine a 6.5L diesel, trans a 4L80E. i know this is a stricly custom application but i thought you STS guys could input a few words. car is in sig...


Cody

Silver_TransAm

iTrader: (2)

If there is a visible leak like that the answer is yes it will prevent full boost potential as well as increase the lag of the system. If you want to keep some sort of connection there where you can take the exhaust off use a bolted flange or a v-band style connection, other wise weld that too.

By the way interesting build you have there.

OUTLAWZ RACING

iTrader: (9)

A sealed exhaust will work wonders. A small leak is noticable but it wont kill anything but spool up.

Silver_TransAm

iTrader: (2)

I had a small crack in my old y pipe setup and I could not make over 10psi on my old 67mm turbo, and with no leaks I can make as much boost as needed on the 76mm, so it can kill full boost potential.

Rafedial

iTrader: (7)

thanks for the comments.

thought i would add that the exhaust is wrapped with about 200+ feet of header wrap, high temp silicone coated.

I do have a 3 inch V-band to weld on, but I have been lazy.

From what you described I think it is the problem. Gonna go ahead and get it on tomorrow and report back.

Ohh, and long live the rear mount turbo!!!

engineermike

Guys, the hx35 is a tiny turbo. Guys are running this turbo on 1.6 liter Honda's. The biggest one they made was only a 58 mm inducer, some as small as 54 mm. That turbo is about the same size as a GT30R Garrett, which max's out around 550 hp. Assuming your engine makes 350 hp NA, it would only take you about 9 psi to hit 550 hp. I'm a little surprised you're getting 12 out of it.

Revision... I just searched and figured out the car is a V6. The turbo should do much more boost than that on the v6. However, the fact that it's a rear-mount could be holding it back. I remember a while back, Zombie couldn't get his rear-mount 76 to make over 12 psi on his 6.0 liter, whereas my front-mount 76 won't make LESS THAN 17 psi on my 388. Why not mount it up front anyway? Your car is a v6 with plenty of room.

Rafedial

iTrader: (7)

did I miss something here?

The turbocharger I am using is from a 24 valve 5.9L I6 Cummins truck. The engine I am using is a General Motors V8 6.5L turbo diesel. It is a big block engine. They also come ina 6.2L displacement. Turbo and NA.

A diesel engine usually only has an operating range of 0-3400 rpms. Thus the need for a smaller exhaust housing. These engines run at 9 psi stock, but with an intercooler have been to 15 psi easy.

As an update: this morning. Stayed up all night,bout to go to work. Welded in the v-band flanges and clamped it up. Got about 1 psi more overall. Not much but worth the time. Feels strong.

And to make it clear about the engine. It was rated with 215 hp and 4?0 lb. ft. torque. setup on the Camaro currently is s.l.ighty higher than that.

IT IS NOT A DURAMAX!

Whenyou look at the car you prob think it's just some reg 4th Gen F-body. No, sir. IT is the only diesel powered 4th gen F-body that EXISTS.

EDIT: If anybody wants to see more of the Camaro I built, just check my posts.

Cody

engineermike

It would've been AWESOME if you had put that in the initial post.