Dutch944

in need of more vids..

Voith

Paulyy

Your clock is wrong!!!

333pg333

Well not great, not the end of the world. They had the cam set quite retarded and moved it forwards 2 degrees at a time. Main issue at this stage is it won't make more than 24-25psi. So something is up. Will put in some pressure sensors and see what's going on. Perhaps a different housing or even turbo. X-over is 2.5" in diameter so it's larger than stock.

Duke

Is the lower line torque or boost?

The GTX3582R is a few hundred HP away from being a bottle neck but you are using the 0,82 T3 housing right? Seems a bit odd that it wont make more than 24 25 psi when it made 25 psi with the 3.1l with more power!?

For what it's worth - I run a 2.25" crossover with my 1 7/8 primary headers.

Paulyy

Something does look wrong.


It's not the turbo. Didn't someone else run a 2.5" crossover and ran into some backpressure issues?

333pg333

Lower line is boost. Increments of 5 psi per larger square. Yes it's the .82 housing. We didn't try boosting much over that previously. The 552whp hit a short peak of 25psi. I think we have to look at backpressure somewhere. Isn't the stock X-over 2" or is it 2.25"? This is larger than stock but may still be a bottleneck overall.

Duke

I'm convinced the crossover is not the issue here.
I hit 514 rwhp with tiny stock headers and stock crossover pipe with the 0,82 housing. On my latest engine I'm using 4-1 headers with larger primariers with 2.25" crossover. You don't want volume in that pipe, you want velocity. Measure back pressure and if it is high change the turbine housing, not the x-over! You already have a larger crossover than me and I don't have these issues at 620 rwhp.

333pg333

Yes. No point in guessing until we know. Will be testing the car at the track on Thursday so that will give us a bit more of a real world assessment.

refresh951

Spooling very late. How much overlap on the cam?

Geneqco

Well I think the really encouraging thing here is that you have very little HP drop off all the way to 7,500 rpm and the drop you see is actually due to the drop in boost pressure. From the chart, it looks like you should even continue to make a little more HP even beyond 7,500 rpm once you have the boost issue fixed which is really impressive for an 8v.

I guess you've been down this road a few times now... I think it's probably just a little teething issue you'll get sorted out fairly quickly!

Thom

A wild guess perhaps, but maybe there is not enough exhaust flow to spin the turbo as much as required to build more than 25 psi, assuming the "high"-flowing top end... which could simply point us to a leak between headers and turbine - faulty wastegate?

If there was a problem with excessive back pressure then the hp curve would not look that good up top - we would need a high-flowing larger capacity engine to choke a GT35 0.82 hotside.

Duke

For the first theory that would create another type of boost curve. It would generate higher boost the higher the rpms and not a boost curve like this where it starts to fall off.

Maybe have the turbo checked or try another turbo if you have one available.

Thom

Are you suggesting that an exhaust leak before the turbine should cause an increase in boost?

thingo

Don't know if there is much to be gained by having the crossover that big, it'll give you more back pressure and slower spool I'd think,but you've got a big turbo there for a 2.5.