KR vs EGT vs 02s

[wicked6]

Ok everyone chime in here. Yesterday when I was testing and tuning with a fellow GN member/owner I had 0KR, 1620EGT and high 700s o2s. Just before that I had less than 2KR and 1724EGT and a low of 760s on o2. This had me thinking!!!! Oh my god my EGT is pretty high. I do not want them over 1600. But, there was no KR. So my question is what is more/most important KR or EGT?

Is it fine if I have 0KR and a max of 1620 EGT on a run. Or am I looking for trouble. For those tuning and they have all the gauges and equipment to measure this, what is the rule of thumb?

BTW, I was running 24# boost, 48# FP line off, pump gas/alky and 24deg timing.

 

[BLACK6PACK]

The 1620 EGT, I wouldn't worry about. The 1720 is getting pretty high. Find what is faster on your car in between 1550 and 1650 and run with it.

 

[Razor]

Your EGT probe is probably one of the most accurate indicators you have for engine tune.

You have three systems..the O2,the knock sensor,and the EGT.

You may have a bad knock sensor..this could be a possibility..

For me 800 for 02 gets me 1520 egt,750 gets me 1630,so anything above that would appear to be really lean.Not saying my O2 is accurate..but its a rule of thumb in my car..1700 is danger zone in my opinion...May have to start looking at plugs to see if they're coming out white after a run.

My .02 cents

 

[BM Computer Src]

The knock sensor is fine, and the O2 sensor and the EGT Gauge agreed perfectly. Whenver it would dip into low 700's, the EGT's would be much higher (high 1600's - low 1700's). I was pleased to see the end result, which was low 1600's, consistently.

See ya,
-Bob

 

[wicked6]

Thanks again bob for the time and helping me tune my car. Hope to see you soon at the track and hopefully I can finally get that elusive 11. This way I can be competition for Razor.

Razor-> When can we get together and figure out the homemade cold air kit. You know all the places to get the necessary equipement. If we discuss it further I will be more than happy to get and acquire the hardware. Bob is also very interested.

 

[wicked6]

Also, I must take into account that we where not running straight denatured. It was a 70/30 mix of denatured/water. This will cause a leaner condition than with straight denatured which I am going to go back to again. It is better to safe than sorry right. Hopefully this will bring down my EGTs and allow me to run 1-2# more boost safely and "safely" is my keyword here.

 

[Steve Wood]

Quit looking at the numbers which are completely meaningless on the O2s in particular. Find what makes the car run faster. It may go faster at 1575 than it does at 1720. Or it may go faster at 1720. There are no magic numbers, only what works for your car. Watch the knock retard, it is the only valid indicator. If it knocks go fatter....but otherwise, find out what goes faster, leaner or richer?

I would stay with the diluted alky as alky has less fuel content than the equivalent amount of alcohol. I use 60/40 alky water. As long as it is not knocking, it is doing its job.

 

[c&cgn]

Most guys use O2's to tune since they don't have and EGT. O2's have been used for years but are not entirely accurate. If you were using a brand new O2 sensor, then you now have a good correlation as to where your EGT's will end up in relation to O2's. That's what I did at the track and now know that @ 760 O2's my EGT will be in the 1650 range, and that is where my car ran it's fastest time.

My O2 vs EGT #'s were all screwed up on the runs prior due to having an old O2 sensor. IE O2's were mid 800's and EGT's were mid-high 1600's. I would trust the EGT and the KR more than the O2 sensor for that very reason.

 

[azgn]

keep in mind that a too rich condition can cause high egt's also (fuel burns in the manifold)..... look at the plugs to verify you are in the ballpark

every car is different

experiment a lot....there is nothing sacred about 1500-1600 egt.....I used to run my car at 1600...it actually goes faster at sub 1500 egt.....like 1480...since I don't have an 02, I can not correlate the two...

I imagine using race gas vs alky has some impact on egt but I do not know what...maybe Steve has some data?

 

[Steve Wood]

I don't know a lot of facts other than the O2 is only accurate at its midpoint. I also know that the hotter the sensor gets, the higher it reads which is contradictory, I think, to hotter is leaner....

I know that my cars all seem to run better over 800 than under on 93 octane. Bruce has pointed out that his car runs best at 840 and the wb o2 does not think it is excessively rich in spite of the 840.

As 93 octane is not very knock resistant, I tend to tune for the same kind of numbers (over 800) and back off the boost when I can no longer control it with the alky. I find the addition of water to the alky makes it easier to tune and it does not flood out as easily when you add the water. I use a little rmi-25 in the bottle for lubrication.

I believe there are no magic numbers and you still have to do some tuning by means of trial and error to find out what egt your car likes. I believe in results and no knock over any O2 or egt number. The egt number that your car runs best at is a pretty good indicator to tune to once it has been established but you cannot assume that some number is good unless your car runs the best at that number.

 

[wicked6]

Thanx for all the replies and comments. It puts my mind at ease that 0KR and above 1600EGT is ok since KR is the major variable to keep an eye on. I ran my best times so far with a 1640EGT and 0KR. but until now I was a little worried about the high EGT.
I will continue with my tuning and see if my car likes it richer or leaner.

 

[c&cgn]

Originally posted by wicked6
Thanx for all the replies and comments. It puts my mind at ease that 0KR and above 1600EGT is ok since KR is the major variable to keep an eye on. I ran my best times so far with a 1640EGT and 0KR. but until now I was a little worried about the high EGT.
I will continue with my tuning and see if my car likes it richer or leaner.

I also ran my best ET around the same EGT as you. I think mine was 1638* if I remember correctly. That was with an excessively loose convertor, so hopefully thing will be even better now that it has been tightened up.

My combo is quite similar to yours, other than I used C16 gas instead of alky.

 

[Razor]

I aint no competition when looking out my rear view mirror

J/K..you ought to be in the 11's by now..I'll be at the track Thursday nite..call me next week sometime so we can devise something.

Ok..