Why did you even change the rear housing from twin scroll?

 

the FP housing flows more, was looking to extract some more peak power out of the GTP 792.

Tried the car on the dyno today with a full straight pipe, made almost zero difference...back to the drawing board

 

I think an MHI housing will wake the car up. Just make sure it's ported well...CBRE or SoCalPorting are my two choices...but a housing from the states, then have it ported and sent over.

 

GT Pumps have a housing they can supply me, sending it to the USA to get it ported is not really a feasible option unfortunately. My engine machinist is a gun with a die grinder so I might have a word to him about porting it.

Do people typically get them match ported to the manifold or cleaned up everywhere?

 

There can be a lot of porting done around the wastegate ports. You can also gasket match the inlet to the hotside (and technically a little porting/matching of the outlet). Just give your machinist the gasket you'll be using between the manifold and turbo. You can port the manifold to match the gasket as well.

 

You're almost boost limited with the 792 i'm quite sure, A few of the 762 spat the dummy with some big boost thru it.

A 792 on E85 should go almost ~380+ a stroker if everything is right.

Imo FP based frames just seem to make the power so easy like a green would walk it in the park on your setup.

 

The 792 was created to slow the shaft speed down a bit on strokers that push more air...

yep 380 is about what I thought it would make, hence the head scratching

Will be checking cam timing thursday night with a degree wheel to see if that is the issue

Did a pressure test on the cooler with 2 boost gauges and some road driving last night, at turbo side its seeing the same boost pressure as the inlet manifold so no leaks I suppose

 

I'm still confused on why you're scratching your head on power? It's gonna take a lot more boost pressure to hit 380kw/510whp than the 26 or 27 psi your dyno shows you're running.

You'd need to push 30+, and probably closer to 32-34 to see those numbers on a DD.

Am I missing something?

 

More boost made a negligible difference to peak power, so there was no point adding any more.

Im aware of the boost level it will need to reach that sort of power but getting it to climb above 340-350kw will be a start first

Also its worth noting this is a higher compression motor (9.8:1) achieved using 2.2L pistons so it should be a snappy little ****er id think

 

If more boost made negligible power, I'm at a loss.

I'm in the same boat as you 9.75 CR with a 2.3, although my motor is not together yet.

How many #/min is that turbo rated at? Also, what kind of BOV? Could boost be leaking off somewhere?

 

No bov at all
no leaks that I can hear/see
65LB/min im pretty sure

 

Basing your location I take it Mike did you're build he seems to know his away around those motors.

I'm pretty stumped, I know of a few guys on the VIC forum using the 792 with MHI housing and pushing 380-400kw DD which would equiv Mustang.

I myself had a 2.4LR 9.3CR with a BBK Full on ~30psi with 301kw virtual dyno in Mustang mode, Have gone to a JB FP Black with the Tial Housing it's a bit late but feels rewarding on the road no numbers just yet.

 

Keep the boost between 28-30 psi, no more than that, tell your tuner to work more on the map, using more timing.


Make sure the evc or mbc or 3port ecu,whatever you are using, along with the external gate, can hold the above boost up to 7k at least.



Re-setup the cam combo to +1 +1 no matter what cams you are using and go from there , change the combos accordingly, as long as the valve springs are the right ones for the cams you are using.


You need to work on the dyno with your tuner on mapping and cam setup, until you are satisfied with the numbers and powerband.This being said, if you are using gsc s3 or keldords 280s or anything similar change them to hks 280, kelfords 272, s2, or even better jun 272. The more aggressive a cam is the more it pushes numbers and powerband to the right and the specific turbo you are using is low down middle powerband specific, more than upper powerband one. In other words it does not push the proper amount of air up top to support or take advantage of a really aggressive camshaft but you are left with the laziness of it down low and middle of powerband where this turbo really shines.










Marios

 

yep mike built and tuned the motor...which is concerning because he is the guru and does not know whats causing the lack of top end power

 

Me and the engine machinist/blueprinter are going to check the cam timing tonight with a degree wheel on the crank, real arsehole of a job with the motor in the car but we have to get to the bottom of this issue

Cams (kelford 272) and Springs (GSC) were all brand new stuff bought for this motor

The motor is the perfect package it has the best of everything for what I want but there is something wrong.

I have faith that the tuner knows what he is doing with the car on the dyno so I highly doubt it is a tuning issue, something is not working correctly