Stock Exh Temps

[88_pacifica]

Ok guys, I bought the Prosport Exh temp gauge and also 30# Boost gauge, have it all hooked up and they're both working like a champ. However, I have a question regarding EGT's for my application currently.

Basic 2.5, +.020 over stock rebuild except chrome-moly's, BS's removed. I have a mildly ported intake and exhaust manifold. Garrett T2, small 2.25 ported SV for now(will change soon to 2.5) and NOT IC'ed yet(coming soon). I have the stock T2 injectors, stock FP regulator, stock fuel pump(55 psi verified w gauge) and stock 88 exhaust and DP with an auto trans. Everything appears to be running well.

However these are my temps:
Idle- 12-1300*
Part throttle(no boost)- 13-1400*
Part boost- 14-1550*
Full Boost- 1550-1650*

Now, my questions are these regarding those temps. This a relatively speaking "stock setup" right now and I plan to stay within the normal boost #'s for now. but, are these safe temps. I have read that people are at 1400 in part boost and I'm slightly higher. What is the "high end" figure for these motors bone stock? Am I safe for now? I have considered +20's but I don't want to have crappy gas milage and the need for an adj fpr and all that.

When I IC it, will exh temps drop considerably? I can't see it doing that, but I guess it "could" since it's "somewhat" cooler. Also, when I open up my exhaust will it drop as well? Again, I guess it could, but I think that's doubtful. Am I really on the "ragged edge" of safety? My big concern is a "safe reliable car until I re-supply my funds to keep adding on here. SO, what are your thoughts guys? I will add more as I think of more. Thanks all...

Nate

[88_pacifica]

Bump... Anyone with experience in this area?

[Frank]

I think they are two high.

Where did you put the sensor?

[Tony Hanna]

^+1
Could be due to ignition timing though. What's your base timing set at?

[Frank]

Very good call... something we all forget.

[88_pacifica]

stock 12* and sensor is in the #4 runner. Should I advance the timing a few degree's? Get it to "detonate" a little sooner?

[Tony Hanna]

stock 12* and sensor is in the #4 runner. Should I advance the timing a few degree's? Get it to "detonate" a little sooner?

I wouldn't. The fact that your EGT's are that high with stock timing (retarding timing increases egt's) leads me to believe that it's a fueling issue. Too lean or way too rich will cause an increase in egt's. Without a way to monitor AFR, you're prettymuch stuck reading the plugs to figure out what's going on.

Try this: Buy a new set of plugs and install them. Find a nice stretch of road with a wide shoulder where you can safely make a full boost run. Right at the point where you're ready to lift off of the throttle, shut the key off, throw it in neutral, and coast to a stop on the shoulder. Now let the engine cool a bit, pull the plugs and have a look. Brown or black on the porcelin indicates a rich condition, white indicates lean, and a light tan is just right. Speckles of carbon or aluminum on a white insulator indicates detonation as a result of being excessively lean.

If you have a digital camera, take some pics of the plugs, and post them up here. We'll try to help you figure out what's going on.

[88_pacifica]

Thanks Tony... I'll give that a shot on the 4th since I have that day off...

[Tony Hanna]

You're welcome.
Let us know what you figure out.

[moparman76_69]

using that as a guide and going by the plugs when I pulled them the other day you're rich.

[Tony Hanna]

using that as a guide and going by the plugs when I pulled them the other day you're rich.

Problem is, you really need to read a new set that's had the engine shut down immediately after a full boost run, or you'll be seeing the effects of idle and part throttle which can be misleading (could be running rich off boost but lean on boost).

[guyd_15]

It's easier to read the plugs if you use 104+ octane booster (Gus Mahon idea) add a can when you have just a few gallons of gas in the tank. It will give the plugs a reddish color, unleaded gas doesn't color the plugs much.

Guy

[Stratman]

That really shows how equal the injectors are firing between the cylinders and the dark red seems to make signs of detonation harder to see.

[shadow88]

Aside from the ignition timing point which was a great point, another missed question was the boost pressure. If you added a 30 psi boost gague, it's probably because you're running more boost than the computer can make adjustments for.

Get to that IC install.

What's the boost pressure during those WOT runs?

[puppet]

He said that he was running pretty much stock boost levels.

Tony's suggestion is right on. At least you can be more sure if your rich or lean.
All things being equal you seem to be 100-200* higher than a "normal" EGT range. I'd be willing to bet that it's because you're not IC'ed. Under load ... good A/F ratios included, you can expect higher EGT's. That's just how it is.
You might consider advancing the ignition 1-2* at this point to cool him down some. This will shift some of the heat to your block (read coolant/oil).

[TurboJerry]

I would try to retard the ignition timing *first* 2 degrees to actually see if it lowers the egt's. I always noticed that egt is a bell shaped curve, so I try to find out which side of the bell I'm on *first* before making more changes. Advancing the timing may cause more knock, and the egt's will shoot up even higher.....

[88_pacifica]

He said that he was running pretty much stock boost levels.

Tony's suggestion is right on. At least you can be more sure if your rich or lean.
All things being equal you seem to be 100-200* higher than a "normal" EGT range. I'd be willing to bet that it's because you're not IC'ed. Under load ... good A/F ratios included, you can expect higher EGT's. That's just how it is.
You might consider advancing the ignition 1-2* at this point to cool him down some. This will shift some of the heat to your block (read coolant/oil).

Good point... I think that at stoich it is actually a slight bit warmer than what we typically feel "comfortable" at. This was kind of my original conclusion before I posted, but being that it's all "stock" settings currently for the most part, I wanted to post up to be sure. I will eventually like to get a WB as a NB is very limiting really. I am thinking +20's with an adjustable FPR are going to be the magic touch here. Especially since I am not really sure that I will be "happy" long term with factory boost levels... but I have to be for now...

[Tony Hanna]

I don't know. Your part throttle/boost temps look reasonable to me. It's the full boost temps that are worrisome. Remember, the stock cal runs leaner at part throttle than at full throttle. I've seen the Sundance (even with an intercooler) get pretty freakin' hot on the interstate pulling a hill at part throttle in boost. At full throttle, it's a different story though. Out of curiosity, what cal are you running? If you're running a stock TI cal, then I bet the port work and Garrett have you flowing more air at full throttle than it's designed to support. That would account for your higher full throttle temps.

Just a thought, but why not rig up a quicky water/alcohol system for it until you get your IC on?

[88_pacifica]

Yep, Stock 89 T1 2.5 cal. I kinda figured the same thing actually. A port and different turbo is likely the source of the higher temps at full boost. I had actually considered alky and I was thinking that might be in the very near future. I think that it is probably a little cost prohibitive I would imagine, but I really have no idea what it would cost since I haven't researched it in depth. I guess thatif I want to get serious I should get a cal, bigger injectors, alky, yadda, yadda, yadda... But I can't decide how far I want to go. remember, this has a 100K mile auto trans so I can't get too crazy. I am not 16, power-braking the piss out of it, but I don't need to pick up an input shaft or carrier parts either when in full boost. So I am limited at this point. I need reliability and "fair" boost, not 22#'s and unreal speed. I have a Grand National for that. I just want the smalll V8 power with 4 cyl sipping when I'm not boosting. I've already thrown over 3 grand at this thing so I want reliability ALOT!I can't make this my everlasting project. I just noticed on Sunday the front crank seal blew on this 20 mile fresh rebuild.... ARGGHHH!!! Now I have to find a sprocket puller... and do it ALL AGAIN!!!

[Dusty_Duster]

I think you should intercool it before you think of doing anything else.