I have my gauges hooked up now and I was making some WOT runs down the highway and this is what I saw
Max rpm 2500
Max boost 18
Max egt 950
Truck was unloaded and I let off the throttle at 85-90

For a second or so when I first nailed it there was a decent amount of black smoke and then it faded to a haze and then none. The PO said there had been tweaks to the IP, but couldnt tell me what was done so I don't know if anything has really been changed.

I have a 3200 spring on order, but it is not here yet. When it gets here, I am going to do some pump tweaking. Fuel pin will come later, when I can afford it. I have read the sticky and done alot of reading all over this site, but I would like suggestions, at this point, as to what to do next.
TIA
Leper



***BTW*** I DD this truck most of the time, pull small trailers occasionally, and every couple of months I pull a 10K load hunderds of miles each way.

 

Sounds like a good running '92 My guess is that the smoke screw is run all the way in and that was the previous 'tweaking' done...that would account for the smokey takeoff. When you do get to the full fuel screw, it'd be a good time to back that smoke screw out some...it's pretty worthless once you crank on the ff screw.

 

How do I up the boost a hair? Does it take modding the turbo more, or will the pump mods help some? Will the 3200 spring do anything when it gets installed(besides increasing rpm)?

 

To increase the boost, you need more fuel and more air. Turn the fuel screw up, drop the starwheel to the bottom then bring it up one turn. (might have to raise it more depending on the smoke you get) Bigger injectors will make a big difference. Turbo improvement will help get the air going quicker to help reduce the low end smoke.

The 3200 spring is going to help a lot also as it looks like you are defueling around 2500 rpm.

Make sure your lift pump is keeping up when you go to full throttle. Mine was dropping to zero from a 7 psi idle pressure. Went to a first gen piston pump - idle is 15 psi and full throttle will vary depending on injectors you have. Mine runs about 8-9 psi with DD stage threes and 4-5 with modified 370's. I think I need to put in a electric boost pump to keep the pressure in the 10 psi range at full throttle.

There are other items that will help but these will get you going.

 

I will check the fuel pressure. I am not wanting to replace injectors at this time, so I will get to the pump mods next week.

Thanks a bunch.

 

The boost you have is fine for the EGT you are seeing.

Set the AFC cone to the deep side and shave the nylon washer as needed before you mess the the main fuel screw. Then turn up the main fuel screw until the EGT's make you nervous.

 

I hit 25-28psi on average and never see more than 900*. Is this right?

 

Yes. The manual tranny loads the engine much harder than even a bombed auto, so, all else being the same, it's not uncommon to see more boost with a 5speed.

 

Is that pre or post turbo? If post, that's about right. If pre turbo, you have one cool running engine.

Well.... maybe not. Seems like I top out at right around 1100 with 35psi.

DP

 

Pre-turbo, mounted in the ATS manifold.

Thanks for the info guys.