High Cruising EGT's

[Turbo84Voyager]

Hi Everyone,

I have been experiencing high EGT's while cruising. The engine is a 2.5 w G-head, wiseco's, TU SS header, T3/T4 46 trim hybrid, volvo intercooler, FWD stage 5 cal (set up for a 2.5 g-head). Base ignition 14 BTC. and approx 10PSI of boost. I am not completely sure of my fuel pressure. It is somewhere around 50 PSI. I started with 55PSI but i had to play with it a little. If I richen it up (raise the pressure) the van is very sliggish off the line. The van runs well and pulls very good when the turbo spools up. At WOT my Dawes gauge lights up the blue light and the EGTs are around 1500. When cruising at 65 my EGTs are 1600 and will climb if I go into boost or go up a hill. Driving around town the EGTs will vary between 1400 and 1550but if I hit a hill they start climbing. I didnt see how high they will go, but on the highway cruising at 1600 I got on it a little (no WOT) and when I got off it was 1660 and still slowly climbing. My probe is center between the head and the turbo flange by cylinder 4. I pulled the plugs and there was no signs of detonation. The grounding electrode was gray and the porcelin did not have much color, slightly on the brownish side. Any ideas what I should do? I have a decent amount of money in this and I dont want to hurt it.

Thanks,

Justin

[glhs496]

If the highway egt's rise as you go faster the motor is leaning out. Best to get a fuel pressure gauge on it to confirm that the pressure is rising with the boost. Also double check the vac line to the fuel regulator to make sure it's connected.

[speeduphoria]

you also get high EGT's from rich A/F, so you would need to know what side of stoich you are on before making adjustments.

High EGT's during cruise wont kill your motor, you prob need more timing in cruise because some of the gas is burning late into the exhaust manifold causing the high EGT's. Same way people spool there turbos with lots of timing retard which causes high EGT's for a couple seconds as the gas is burning in the manifold. EGT is not a very good gauge at all IMO if you know the A/F and have it tuned correctly and know the EGT's for those conditions, then you could use the EGT gauge to see if there is an issue if its not what it normally is. Other then that trying to tune a car with only EGT on a setup that is slightly different from everyone else is not going to get you anywhere.


What octane gas are you using? What heat range plugs and gap? How much boost?

[Turbo84Voyager]

The regulator is connected and I am assuming is working correctly. It does raise the pressure when I pull the line off and the van does not go lean at WOT.

I am running approx 10 PSI of boost.

I don't believe I am lean, Cindy said they added quite a bit of fuel to this calibration and I had to lower the fuel pressure because it was too rich at 55PSI. The van was a dog off the line. After playing with the pressure I got it to run good off the line and still go rich at WOT.

What are some signs of high EGT's on the spark plugs? I am wondering if the gauge is not off.

I am going to connect another A/F gauge and see what it reads while cruising since the dawes is not lit.

Any other ideas?

Thanks,
Justin

[speeduphoria]

Oh I reread your 1st post and found your problem.

2.5 G head, many with this combo always have high EGT's , over 20psi they could not keep it below 1700degF. On the other site a couple people have had this issue. While using stock cast pistons and these higher EGT's and 20+psi they had zero failures from these EGT's. Also cam timing can effect EGT's also

[Turbo84Voyager]

I can hit 1700 degrees climbing a hill with very little boost. I am not having any EGT problems at WOT as far as I know they seem to stay around 1500. I am only running 8 psi until I break it in.