Would TBitz's EFI fuel injection help my engine's pre-detonation...?

[dd74]

Again, L.A. weather was VERY HOT! The dreaded Santa Anas that drive allergies crazy and make my '83 clatter like marbles in the can while in the higher rev range - 4,500 RPM and higher - have returned. Not to mention the traffic was very thick - yes, moving - but very slowly. Literally the air, even as I write this at 10PM est, feels like 80 degrees. There is no wind to speak of.

Tyson and I have been through this issue at least a half-dozen times, and improvements have been made except with the high temp/high RPM knocking.

So my question is, given I adapted TBitz's EFI fuel injection to my engine, would it help prevent the detonation. I'm not as much concerned with power gain - my engine's powerful enough for my needs. I just don't want to blow my motor on the Cahuenga Pass...

Any ideas?

Thanks.

[Steve@Rennsport]

Hi:

I must tell you that if your engine is detonating from 4500 on up, you either have too much total timing, or its too lean (or both) for the 91 octane fuel.

You're going to buy new rings (and possible pistons) unless you fix that immediately.

[dd74]

Originally posted by Steve@Rennsport
Hi:

I must tell you that if your engine is detonating from 4500 on up, you either have too much total timing, or its too lean (or both) for the 91 octane fuel.

You're going to buy new rings (and possible pistons) unless you fix that immediately.

Thanks Steve but...

The timing is set at OEM spec. Mixture has been adjusted via a dyno sheet that shows lean to rich conditions. Again, this occurs in extreme ambient heat, and at WOT. It does not otherwise occur in more favorable weather conditions.

I could always drive the car like an old man afraid of speed when it's hot out, but what fun would that be?

I could just avoid heat altogether, but by then, the car is worthless to me. L.A. is more hot than cold and has more traffic most times than clear lanes.

Any other suggestions?

[Langers]

JMHO, but I don't think the factory engineers imagined people would be running the cars at factory timing using 91 octane fuel in hot conditions! Retard that baby...

Other suggestions? - full standalone engine management with knock sensors.

Is anyone else with your engine in the same climate having the same problem? When you say lean to rich running conditions, where is it lean, where is it rich?

[RoninLB]

your heads are getting too hot for your driving conditions. You could cool them with a richer mix if that is an option.

[dd74]

Originally posted by Langers
JMHO, but I don't think the factory engineers imagined people would be running the cars at factory timing using 91 octane fuel in hot conditions! Retard that baby...

Other suggestions? - full standalone engine management with knock sensors.

Is anyone else with your engine in the same climate having the same problem? When you say lean to rich running conditions, where is it lean, where is it rich?

Hmmm...maybe I will retard it.

Full standalone...at $5K?

It actually doesn't run lean at all. It ran fairly rich during a dyno run, then we enrichened the mixture even more as it got hot out here...

[RoninLB]

maybe a couple steps colder plugs to see what happens ?

[Langers]

You live in CA, I thought you guys had cash coming out your arse?

Full standalone shouldn't be anywhere near US$5k. Having said that, Australia seems to be a world leader in cheap standalone units (Wolf, Autronic etc).

[dd74]

Here's the dyno sheet. The graph on the bottom shows the a/f ratio. Too rich? Too lean? Any ideas?

[Langers]

I'd say that's too lean at high RPM. 14.7:1 is stoichiometric, and I'd want to run considerably richer than that at high RPM in a hot climate.

However I'm sure Tyson would have already considered this, so I'm out of ideas!

What are Tyson's suggestions for fixing the problem?

Oh yea you don't have significant carbon buildup or anything do you? Could create hot spots and increase compression ratio if it's really bad.

[dd74]

Originally posted by Langers
I'd say that's too lean at high RPM. 14.7:1 is stoichiometric, and I'd want to run considerably richer than that at high RPM in a hot climate.

However I'm sure Tyson would have already considered this, so I'm out of ideas!

What are Tyson's suggestions for fixing the problem?

Oh yea you don't have significant carbon buildup or anything do you? Could create hot spots and increase compression ratio if it's really bad.

Tyson richened the mix. But today was an unusual day. I mean there was no wind. Brushfires kicked up everywhere. You know...rub your shoes on the carpet and touch the nearest electrical device and voila - you've created your own lightening storm...

Anyway, "stoichiometric" -- now that's a word.

I'll see about running it richer.

As for carbon buildup, yes, the traffic was unnervingly bad - stop and go, stop and stop and no-go, all because of the clowns behind the wheels wanted to see the pretty hillsides flare up in smoke. So, if carbon can deposit itself in roughly thirty minutes of *****ty stop and go driving, then I probably have just that.

Now, how do you steam clean these motors?

[Langers]

Nah the carbon buildup I'm talking about would come from 10 - 15 years of driving in those sort of conditions.

But yea, we'll see what Tyson has to say, and whether anyone else has the same problem

[dd74]

Originally posted by Langers
Nah the carbon buildup I'm talking about would come from 10 - 15 years of driving in those sort of conditions.

But yea, we'll see what Tyson has to say, and whether anyone else has the same problem

Thanks, Langers. I can always count on Oz this late at night.

[Langers]

Oh actually, does your car have vacuum retard on the distributor? Have you checked it's working properly?

[beepbeep]

Yeah, that's too lean for WOT in hot conditions. Should be sometinh like 12.8 - 13.0

[Langers]

LOL I was actually right about something