John H

After listening to y'all talking about EGTs and boost, for the last few months, last week I had a 16cm turbine housing installed, a full set of gages put in, the KDP fixed, and a mild tweak made to the pump. Boy what a difference. Just about zero turbo lag, and one heck of a push in the rear when I nail it. Last time I had this much fun was my first date in a car. Well not really, but close!

However, I now have some questions I hope some of you out there can answer.
Running without trailer, the maximum boost I can get is about 14 psi, and EGts of 1050F. Does this sound about right for a mild tweak. I don't want to overload the transmission. Do you think I can go higher without incurring a tranny rebuild?
I assume I might experience higher temps when towing, or during summer, and I have heard I should keep the EGTs below 1250F. Must I never exceed that temp at all, even if only for a short time? Or is there some leeway?
I have the 4 speed auto, I have heard the max temp I should keep below for outlet temperature should be 190F, is this a hard number, or is there some max temp I can use that might be higher for a short time?

John

BigBlue

That boost seems a little low to me. I'd check for leaks somewhere.

wannadiesel

BigBlue is thinking of a 2nd gen. The numbers sound fine to me, you're not loading the engine hard enough with that slushbox to make a lot of boost, and your EGT's are good. By the time your pyro reads 1250, the actual EGT is higher than that. The response time on the gauge is not instant, it has some lag time. Don't get all paranoid about it, but if you see that you're over 1250, back off (unless the other guy is beating you).

John H

Wannadiesel, I noticed while driving back along I70, after having the work done, that if I nailed it at the bottom of a long grade, the EGTs would climb to about 1050F with 14 psi boost, but then as the speed built up, the boost would drop back, and the temps would drop to about 950F. By the time this happened I was up round the 90-95mph mark. Why would this happen, I expected to be able to maintain those values?

As you can see, I took your advice and got the KDP done.
Thanks.
John

Redleg

Take the cover off your fuel pump, carefully lift the rubber diaphram. Turn the fuel pin 90 deg., so the steepest part of the cone is facing the little whole where the fuel pin comes out to ride against the cone (towards the front of the engine). Be carefulnot tolose the white nylon washer when you lift the spring out. Mine stuck to it and almost got lost behind the pump. Some guys even shave this down for more performance. You should be able to search for the minimum thickness in the 1st gen forum. Then, start tinkering with the star wheel.

John H

Recognizing that I'm gear challenged (auto), I have a concern over whether I will trash the transmission if I push the power up too far. I asked the guy who did my upgrade to give me a mild pump tweak, and he tried to do his best, but he admitted he was just guessing. I think I caught him off guard by only asking for a mild tweak. Everyone he'd met before me had asked for everything he could give them, so I think I was the first to ask for less. I really only asked for a mild tweak because I didn't know whether I could get into trouble without knowing it, if I had too much power. If I take it all the way, is it easy to control so as not to get into trouble? And what do you look for to tell you that you are getting into trouble? Just EGTs and tranny temp?
I spend just about all of my time towing (about 8000#), so if I take the pump adjustments all the way, will I be able to get the same performance as a mild tweak by just backing off on the accelerator pedal, or will I lose out by hitting against one of the limits like EGTs before I would have at the lower power setting?

John

wannadiesel

By that speed the governor was defueling the engine. Less fuel=cooler EGT. Put in a 3200 RPM governor spring and you can keep it hot up past 100. To answer your next question, yes, you can let off the accelerator to keep the EGT's down if the thing gets too hot. I'm no auto trans expert, so I don't know how far you can go before the trans fries. I do know that the non-lockup torque converter makes the 1st gen autos more prone to cooking the fluid than the newer trucks.

John H

Ah!! Never thought of that. That makes sense. This weekend, I get to hitch up the trailer and give it a proper test. It will be interesting to see what it gives me under full load. I may be back with another question.

John