Slow spool..Lost 5psi

[thumpertrev]

This is probably a no brainer to most of you but here it is. Just got my truck back from tranny shop. Its not on the road yet..so all comments are shop yard relative. I had a fresh rebuild and a low stall converter put in. Doing the typical brake stand to build boost it will only muster 15psi with lots of smoke and quite a bit of time (maybe 10sec). Before converter, compound turbos and other parts I could get 20psi and then wheel spin. Once the truck rolls about 50ft boost comes back in and it gets movin in a hurry! Is there something I can do to get back some of the low end I've lost? Retard the pump?

Parts are, Turbos-WH1C over a Detroit 6v93(tv75?)
3" charge piping
largest aluminum I/C I could fit
5" turbo back
SDX11 5x12
mild head porting
ARP studs
Throttle mod
ground pin ( although currently in stock position to try and help with smoke around shop)
Star wheel 2.5 from bottom
Fuel pressure is regulated at 8psi
A518 with low stall converter
Stock timing
Stock fuel screw
4.10 gears

All of this is in a 94 F350 crew cab dually 4x4.

[oldestof11]

Lower stall= Less RPM= Slower spool.

I am assuming it is about 1500 RPM stall? Do you have a tach?

[thumpertrev]

No tach yet. I realize it will never spool as before but Im just trying to make it a little better if I can.

[SNOOT]

You can put a smaller exhaust housing on the turbo but what you are seeing will happen with the tighter converter. When you get it on the road it should accelerate much faster.

[thumpertrev]

Then I'll wait for the plate. Thanks for the replys

[dvst8r]

Seems obvious, but pressurize the system and check for boost leaks.

[thumpertrev]

Done that already. I think now its just a rpm problem. Getting it registered next month so I'll have a better idea of how it's gonna behave then. The high pressure turbo is a stock WH1C, would a different turbo, maybe an hx35, or a 60mm upgrade help?

[SNOOT]

I didnt know you had twins on my first reply...

Scratch my last reply above. Sir you need to get rid of all of your 3" intake tube. You can leave the bigger I/C just get some reducer boots. Also how big is your cold pipe?

[dvst8r]

I didnt know you had twins on my first reply...

Scratch my last reply above. Sir you need to get rid of all of your 3" intake tube. You can leave the bigger I/C just get some reducer boots. Also how big is your cold pipe?

What is wrong with 3" charge piping? We run 3" on this truck: http://www.youtube.com/watch?v=mZvlo4xxfLk Makes well north of 1000hp.

[SNOOT]

Nothing wrong with it but if he wants to get rid of some of the lag he needs to reduce the size of the tube out of the small turbo and into the engine and it will be less volume he needs to fill... Not talking about the cold pipe.....And there is a huge difference between 1000hp and a 300+ hp truck... His new converter may not be helping him either...

[Tacoclaw]

Though I wasn't able to find it, I remember reading about some import owners doing a dyno test of their intercooler piping. The difference in spool time from going 1/2" bigger throughout the system was in the millisecond range.

I know that the difference in my truck, going from non-ICed, to that air-water setup I have now, and even with with all the different piping setups I've had on it, spool-up has always remained about the same.

[thumpertrev]

It'll be registered in about 2 weeks, after I get my rear ring and pinion to match the front (3.54). I'll post a vid of what it does so you can see what I do.