low EGT's but good power

[marshall]

i recently set my base timing back to 5*, i had been moving it around haphazardly (i didn't have my timing light) it turns out it was retarded pretty far. so i advanced my timing back to the stock 5* BTDC. before when my timing was retarded i was getting good EGT's, up around 1525* at the top of third on a WOT run. now i barely get to 1400 at the top of fourth on a WOT run but the car feels stronger...

i'm comparing runs with ~5 counts of knock, 21-23* timing advance. i had to add about 10% fuel back with the S-AFC in order to get my knock back down after i put my timing back to stock.

so basically, should i retard my timing back to where it was (about 2* ATDC @ 750 rpm) and get my EGT's back to 1500*+ or should i keep my timing at 5* and keep my 1400* EGT's?

thanks for any advice,
marshall
streetdynamics.com

 

[nowayout]

Were is the probe tapped.
is it in the manifold or down pipe.


it's make a big difference in temp.


Lue

 

[L2RTSiAWD]

keep your timing stock as long as your car feels good don't mess with it.

 

[marshall]

EGT probe is in #1 runner, about two inches from the port opening.

mutted - thanks, i'll see how it does at the track tomorrow. i suppose that is the best way of testing...

thanks
marshall

 

[nowayout]

your reading should be as good as it gets.



lue

 

[Enigma_Man]

wouldn't having a retarded timing possibly allow still-burning fuel to go out the exhaust manifold, thereby giving a higher EGT reading?

-Jesse

 

[marshall]

most definately, i suppose what i was most wondering was why my EGT's are so low. everyone says tune for 1550*F or so. right now i'm tuned for 3-5 counts of knock, 20-21 deg of timing, 18 psi, .80-.82 O2 and I'm getting 1400*F EGT. i'm pulling out about 5% across in the high table of my s-afc.

marshall

 

[marshall]

the car went 8.10 @ 85mph, so i guess 5* BTDC works just fine, previous best was 8.35 @ 83.

marshall