well, i went racing last night and it was a disaster. on one of the runs i couldnt rev past 6-7000ish even though my launch control(8000) ran fine. so i figured i ran my gas tank too low which has happened before. so my only option at the track was 112leaded race fuel. i got 4gallons and as soon as i left the pump i noticed my car was detonating on partial throttle. so i panacked and reburned my chip. ran onc and ran the same times but something didnt seem right still. so i parked it and waited till race was over and swapped tires and drove it home. this was scary, since my car started bucking and partial throttle was still detonating. i tried to check out my a/f but of course when i needed my laptop to work the most it crashed. well i checked out my a/f today and it was really lean. iburnt another chip that i know never detonated and it seemed a little better however still seems like a little detonation.

my compression is 12:1 and its a 2liter. i am running 25degrees total timing and that seemed more than conservative.

why is my car detonating??????? im freakin out here. could thge race fuel be doing this??? maybe im not running enough timing?? why was my car running soooo lean?????

opinions are very welcomed since im at a stand still here. my tach has been jumping all over the place lately so im sensing that my ignitor is on the fritz once again. but i thought that the ignitor was just a slave and the ecu controlled which cylinder fires.

sorry for the long post but i figured thi would be the best place to ask about the race gas.

 

if your tach is giving funny readings, probably you have a bad distributor...

when you tuned your car, did you change anything major? what was the afr ? wot? whats the peak timing and where?

 

[QUOTEwhy is my car detonating??????? im freakin out here. could thge race fuel be doing this??? maybe im not running enough timing?? why was my car running soooo lean?????
[/QUOTE]

rich/lean will cause misfire
to much timing will cause detonation

Assuming you tune your own car and burn your own chips you I assume you know the difference between detonation and misfire. It sounds more like a misfire but your description was a little brief. Check into ignition related components(ie coil,dist,plugs,wires). What do the plugs tell you?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1840cc &raquo;</TD></TR><TR><TD CLASS="quote">if your tach is giving funny readings, probably you have a bad distributor...

when you tuned your car, did you change anything major? what was the afr ? wot? whats the peak timing and where?</TD></TR></TABLE>

Ive never dyno tuned, just dyno baselined. however i have street tuned it. wide open throttle was at high 12's low 13's. my timing is stock pr3 with about 3-4 degrees taken out up top aand about 2-3 every where else. My car NEVER detonated on this program before. I baselined at 226whp and 155wtq with this map.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by IMALLSLO &raquo;</TD></TR><TR><TD CLASS="quote">

rich/lean will cause misfire
to much timing will cause detonation

Assuming you tune your own car and burn your own chips you I assume you know the difference between detonation and misfire. It sounds more like a misfire but your description was a little brief. Check into ignition related components(ie coil,dist,plugs,wires). What do the plugs tell you?</TD></TR></TABLE>

It sounds like theres a bunch of marbles inside my engine.lol I havent inspected the plugs yet but i checked the timing and its set at 15degrees at idle so everything is cool there.

i know that running to retarded can also cause detonation. Do i have to raise my timing with race fuel???? is it possible that my engine wanted race fuel all along and has started to run lean becuase its trying to make more power on race fuel??? im gunna drain out the 112 leaded and put some 93 back in it and see what happens i guess. i dont have any experience with race fuel, so hopefully i didnt hurt anything.

 

If your motor is 12 to 1 why would you not be running race gas. The cars that run pump with that compression are tuned to do so. In my book its a matter of time before it start smocking and pinging. 12to1 i would have started that thing out on race gas and left it there.

 

yet again, my motor was tuned on pump gas and had ZERO detonation before the race gas.

 

Is this the same B20 thats for sale cheap?? hehe

 

ok, lol. turns out my little detonation problem wasnt a deonation problem at all. io built a bracket for my race header and the bolt was loose and chirping/pinging.lol what a huge relief, But it still doesnt explain why i was running about 1.5 points more leaner. does race gas do this????

 

Some race fuels with a lower specific gravity will INDEED run leaner!! That is why on a high compression motor that might need race fuel it is better to just stick with whatever fuel you plan on running. Even 2 different fuels with the same octane could require different tuning requirements. Some race fuels are oxygenated, some aren't. I stick to the same fuel from the same pump for consistency and so I don't always have to change my carburetion. I use 100 octane (Cam 2 unleaded) on my 13:1 d16.