EGT temps-how high is too high?

[turbovanman²]

Just came back from a 10 hour trip, 5 there, 5 back, never done hills, long steep hills before. My egts reached 17-1750 deg going up the very long hills, lol, part throttle, 0-5psi of boost, spurts of 10 psi, going 100-120 km/h very easily. The power was there, didn't seem to drop off, I got scared even though I have forged pistons and a TU cal. I backed off a few times, was I ok leaving it there or was I right backing off?

[moparzrule]

I've hit 1650 before, but 1750 seems excessive. Maybe it's just because of it being a van and the extra load of wind resistance.

[looneytuner]

I would have freaked out. You were right backing off. I think you need to contact Paul on the cal. That's just my humble opinion. I AM crrazy though after 19 years with these cars.

[BadAssPerformance]

I've seen 1700F+ regularly on the highway at part throttle on my old setup that only ran 1400F at WOT at 20 psi. I think it has something to do with part throttle stagnation of the exhaust in the manifold and causes a heat soaking effect.

[turbovanman²]

Hmmm, I am calling him tomorrow so I will ask. I was loaded but only 400 lbs-big deal, lol!

Sorry JT, it has a tubular exhaust header,

[GLHNSLHT2]

we want pics of this tubular exhaust header!

[turbovanman²]

I mean its a log header, sheesh, was thinking tubular when I wrote the addition. Its made by Typert.

[looneytuner]

I have to ask this dumb question. What is your exhaust system?

[turbovanman²]

I have to ask this dumb question. What is your exhaust system?

2.5 inch dp, then 4 inches later, 3 inch mandrel bent system, walker 3 inch super cat and Magnaflow muffler exiting behind the right rear wheel.

[BadAssPerformance]

Sorry JT, it has a tubular exhaust header,

coolio!

[Una]

One thing that always drove me nuts with the stock cals is the part throttle tables. I don't know what Paul does with his, since I never ran his cal on a properly running engine. But if you have an AF gauge, you might notice that the stupid computer is still bouncing stoich if your at about half throttle or less and about 5psi or less.. That's because the part throttle tables, under boost are TWENTY FIVE PERCENT leaner! than the full throttle tables in that same area.. When I do cals for my own cars, I bring the part throttle under boost tables up to the exact same spot as the WOT tables.. Until I get a wideband or get the car on the dyno, I have to assume it needs 25% more fuel at part throttle, rather than say, 15% more, and 10% less at WOT which I'm betting is more like it.. Anyways, running stoich under load and under boost would definitely give you those kind of EGT's..

[turbovanman²]

Hmmmm, I knew he jacks them up, when I finally get around to calling him, I will ask.
My dawes went between red and yellow, and off when it was doing this.

[moparzrule]

The dawes is a WOT only gauge...not lighting up in anything other than WOT is completely normal.

[Una]

The dawes is a WOT only gauge...not lighting up in anything other than WOT is completely normal.

In my cal, it lights up any time your under boost.

[moparzrule]

The gauge lighting up at part throttle has to do with the throttle position not how much boost you have. At 3/4 throttle A/F ratio is supposed to be something like .7-.8ish, which might light up the red light because that one starts at .78V. Less throttle results in less voltage, therefore shouldn't light up the dawes at all.

[Una]

The gauge lighting up at part throttle has to do with the throttle position not how much boost you have. At 3/4 throttle A/F ratio is supposed to be something like .7-.8ish, which might light up the red light because that one starts at .78V. Less throttle results in less voltage, therefore shouldn't light up the dawes at all.

Boost is boost, doesn't matter what the throttle position is. When your under boost,you need to be running 11.5:1 or richer. .7-.8 is far from 11.5:1 (who knows how far, since it's a NARROW BAND sensor), but it's not the .975 or whatever the dawes is targetting to tell you you're at 11.5:1.. It's not normally a big deal, but as Simon noticed.. Go try to climb a mountain pass at a steady speed. That means 1/4 throttle and 5psi for 30 minutes at a time.. I'll take my slightly less fuel efficient but FAR SAFER fuel curves..

[turbovanman²]

The dawes is a WOT only gauge...not lighting up in anything other than WOT is completely normal.

Any air/fuel guage is a WOT guage but it also shows when the computer goes into open loop. Some programs do this at part throttle, like Una's. The stock cal would go into open loop at 1 psi of boost. I had Paul make mine 3 psi of boost as it used to hover around 1psi on the highway and my gas guage would start moving but with my new engine, I now have vacuum on the highway,
If my dawes light goes on and stays on, the computer is seeing boost and going to open loop,

[Dave]

Simon you gotta remember, our fuel curves are only at something like 25% during part throttle. So if you slam it to 20psi somehow on part throttle, the A/F ratio is gonna plummet as is your EGT's. The fuel just isn't there at part throttle.

[omnivore]

You mean the AF ratio will plummet, and the EGT's will do the opposite...right? LOL

[Dave]

You mean the AF ratio will plummet, and the EGT's will do the opposite...right? LOL

I thought A/F and EGT's both kind of tell you how well the mixture is performing? The less fuel and more boost the higher the EGT's as in the higher the A/F's, right??