Timing on vintage 302 Z/28 A/S

[F-BIRD'88]

This is no secret. Try it.

[Truckedup]

This is no secret. Try it.

I would like to know why faster burning race fuel burns even faster with slower burning pump gas...

[GerryP]

Flame propagation for hydrocarbon fuels can vary with fuel types (mostly in the number of carbon atoms in the mix. More carbon atoms=faster flame travel) but gasolines, generally in the C6H12 range, have the same travel rate at stoic. The primary variable affecting flame propagation with gasoline fuels what side of stoic the mixture is on. Leaner means a slower burn, rich is faster.

[Truckedup]

Flame propagation for hydrocarbon fuels can vary with fuel types (mostly in the number of carbon atoms in the mix. More carbon atoms=faster flame travel) but gasolines, generally in the C6H12 range, have the same travel rate at stoic. The primary variable affecting flame propagation with gasoline fuels what side of stoic the mixture is on. Leaner means a slower burn, rich is faster.

Yes, and race fuel manufacturers claim many of grades of fuel have a faster burn for more complete combustion at high rpms and less time for detonation to occur..I have to assume they mean a faster burn than pump gas...

[F-BIRD'88]

Many of the additives that are blended in race gas because of their high resistance to detonation, also burn slower than gasoline does. Can be too much of a good thing. Adding a bit of good pump gas helps. Also tends to help drivability and reduce fouling missfire which also can result in net better engine power output overall.
With a 110 octane and just 11.5:1 CR you have room to blend a bit.

[F-BIRD'88]

Right now you have a 22degree mechanical advance curve. with 18deg initial base timing.

Recurve the distributor for a shorter 10deg advance curve by restricting the mech adv travel to 10 degrees. Now you will enjoy much better idle quality and better throttle response overall and may now not need to give it so much total advance 34-36 ish , YET enjoy much better overall performance.

24- idle 34 WOT
26 idle 36 WOT
Adjust to suit while watching the plugs and the real performance.
Don't get carried away with total max timing and do not confuse with a drag car.

[Truckedup]

Many of the additives that are blended in race gas because of their high resistance to detonation, also burn slower than gasoline does. Can be too much of a good thing. Adding a bit of good pump gas helps. Also tends to help drivability and reduce fouling missfire which also can result in net better engine power output overall.
With a 110 octane and just 11.5:1 CR you have room to blend a bit.

Not true, a false assumption and we have discussed it previously...Higher octane race fuels burn faster, detonation needs time to develop, a faster burn by itself tends to lessen detonation...And TEL doesn't slow the main burn, it inhibits spontaneous combustion of the end gases...

Here's some info from Sunoco race fuel

https://www.sunocoracefuels.com/tech-ar ... ond-octane

Here's something from VP... read down to "Burning Speed"

https://vpracingfuels.com/about-us/faq/

And this is a good read on the causes of detonation...

http://www.contactmagazine.com/Issue54/ ... asics.html

[cv67]

You can try a 110 octane unleaded race gas , (with a lead substitute built in. Will probably make more power yet want a bit less timing too.

WIld Bills Octane Supreme, 6 pack is cheap goes a long way and really seems to work. I can run a few more deg timing, car is happy.

Post up pics of this camaro project..all time fav ride.
Uncle bought a 68z brand new when I was an itch

[BBO Omega]

Consistently using 110 Oct Sonoco Leaded on the Street can lead to really heavy flaking deposits in your Combustion Chambers and Intake Ports. I just spent the day cleaning it out of my heads. I’m probably going to die soon.

[F-BIRD'88]

I got right away from using leaded gasoline years ago.
This is one good reason. I do not use nor recommend any of the lil cans of octane booster. If you want to increase the octane of pump gas blend it with high (110) octane Unleaded race gasoline. This is cost effective and actually works. You got a lot of money wrapped up in your racing motor. What you stick in the tank matters.

[Vintrcr]

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[Roundybout]

All you know when blending 110 octane race fuel and 91 octane pump gas is you have now diluted a perfectly fine race fuel to something else of unknown quality. You'd be better off putting the 110 directly in the tank and not worrying what concoction you've mixed. Especially on a ride like that.

[Dave Koehler]

Geez, is that the way you bought it or was some restoration in order?

[Vintrcr]

IMG_0210.jpg

I did a complete mechanical restoration. Fortunately the car was mothballed and moved from storage unit to storage unit since the late 70's. Lot's of hand buffing saved the paint and the original decals held up well. The 302 was in pieces, but had been kept dry(Nevada). Mice found their way in, but really didn't cause much havoc. My restoration goal was to keep the car 100% vintage correct, other than safety upgrades.
It runs great, and really represents what was running during that era.

[hoodeng]

That's a nice piece of Kit you have there!
Would it be possible to get onto a dyno? that way distributor curving ,final timing and fuel will be set at what the engine is asking for .

Cheers.