egt temperature with alky

[john evans]

I thought I read some info on egt temps. relative to O2 numbers on this forum once.Can someone ,maybe Razor,please give me that info again.Saturday night my TTA saw 1735 degrees with 15 degrees of knock at 26 psi on the street.I was adjusting the boost using Eric's new chip and obviously need to lower the boost alittle.Thanks for the help

 

[V6POWER]

1735 is too high on my car; it runs best around 1600-1620.

 

[4sfed4]

I will offer the suggestion that the 1735 F was due mostly to the ignition retard. KR shoots EGTs up on my car. Its logical that this would happen though as with retard, the combustion process may still be occuring in the exhaust port.

 

[john evans]

You may be correct with that assumption,because my O2 volts were 805.I'm going to turn down 2 lbs. of boost and retest.Do you think high 1600's is still too high for egt.

 

[Razor]

You need to lower your boost a lot. You need to get the motor running cleanly.. then work your way up. No ifs and buts about it.

Now your O2's at 805 indicate it is rich, and you may be putting too much gas whereby its igniting in your headers cuasing the EGT to climb. Also any detonation will cuase the EGT to climb.

Tune for ZERO knock at low boost.. get your O2's in line with mid-high 700's..no KR.. then start upping the boost.

Any KR that escalates as the car moves down the road.. lift the pedal.. and figure out why.

At high boost.. you get that kind of KR.. you'll blow a head gasket.

HTH

 

[4sfed4]

Originally posted by john evans
You may be correct with that assumption,because my O2 volts were 805.I'm going to turn down 2 lbs. of boost and retest.Do you think high 1600's is still too high for egt.

Sounds to me that that was exactly the case.

I dont have a Buick, but if my car was showing 15 degrees of KR, I would certainly take out alot more than 2 psi boost! Turn it WAY down and start safe. 15 degrees of KR is ridiculous (and dangerous). If you are lucky, Ill youll take out is the headgasket. If you are unlucky, you might bend a rod, take out the rod bearings, or damage the crank journals.

And BTW.....I have done all four of those things before when I had some KR

 

[john evans]

Thanks for the replies guys.I'll turn down to 23 lbs.,leave the fuel alone, where Eric told me to start,and retest.Where should I look for EGT to be with alky use,1600-1700?

 

[Razor]

I'd turn it down to 16-18 and work my way up. EGT look for mid 1500's as a street tune. At the track i'll run 1625-1650 no KR.

Get rid of the KR first, if not, "it" will get rid of your motor.

HTH

 

[john evans]

I didn't mention that the previous Sunday,i had the car out with the same fuel pressure, chip and 23 psi, and had 0 knock, 1610
egt and 842 o2 millivolts.In the search for more power,I upped my new RJC boost controller and obviously added too much trying to use up some more of the fuel.Thanks Razor and others for your input. I will keep your advise in mind.

 

[Razor]

Originally posted by john evans
I didn't mention that the previous Sunday,i had the car out with the same fuel pressure, chip and 23 psi, and had 0 knock, 1610
egt and 842 o2 millivolts.In the search for more power,I upped my new RJC boost controller and obviously added too much trying to use up some more of the fuel.Thanks Razor and others for your input. I will keep your advise in mind.

842 is typically very rich and doesnt correllate to 1610 EGT. 1610 is typically in the 760 range. Good EGT, bad O2 reading? You can run more boost by increasing the alcohol to offset the extra fueling at the upper end.

So the question is what scantool are you using to see this 842? And at what MPH are you seeing this O2?

Big dirfference between seeing 842 at 20 MPH and 110 MPH.. huge..

Report back.

 

[john evans]

I ran this in 3rd gear to about 95 -100 on a clear stretch of highway.I know it wasn't like a full bore run at the track,my car usually mph's at 117.5,but i'm trying to dial in my new 50lb.injectors,Eric's 23 degree chip and RJC boost controller.My scan tool is a scan master,and egt digital meter from SMC.I just resently changed turbo's to a pt52 ans I have an AC 9'' convertor 3000 stall.

 

[john evans]

I also forgot,the fuel pressure is set at 43 psi, line off.SMC alky is turned all the way up,as per Eric's instruction.I have a GSCA O2 sensor that is heated.Does that help explain anything.The conv. is non-lock also.Thanks again Razor,I may need to save up for an alky upgrade.

 

[salvageV6]

How many nozzles are you using?

 

[Razor]

John, well at least I have more ingredients

The 842 at the top of third is way too rich. That needs to come down considerably. get Erics chip and drop the BLM lock to 118-122 and see if that leans you out some.

Drop your boost and get the car running 750-770's at 1600 EGT and 0 KR at lets say 22 PSI. Then start upping the boost keeping the O2's inline adding alky or fuel. If you cant get the car running lean and mean at lower boost, it has no business going higher. Higher boost and a rich condition makes no power.. but makes the needle go up. Your high egt is probably unburnt fuel igniting in the header.

Dont know about your O2 sensor. Maybe its bad. Would suck if it was and your chasing your tail. I would replace with a single wire AC Delco(factory AFS20) and compare. Worst case is you now own a spare O2.


next if upping the boost you cannot control KR without richening up the mixture, your out of nozzle/system. Perform the pressure test on your kit and verify at least 75 PSI. Also check your nozzle and make sure its not clogged or ???

If you find your at pump speed 10, and need more, then you'll be looking at making a change to your alky system setup.

A sure fire test if you need more alky is add octane to your gas and see if the knock goes away. If so.. you have something else to tinker with.

HTH

 

[john evans]

THANKS AGAIN RAZOR