Race gas timing, hearing a different opinion.

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B3422w5

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I have locked out dizzy, running timing at 34 degrees. In fact, when I had my 13+ to 1 W5 deal, it seemed to like 32 degrees best.
Was talking to Chris Hardy at RET engine development this morning. Via a mutual friend, he and I have become friends.
I was asking him about possible jet changes going to these new bigger headers.
He asked me about timing, after some jetting tips.
When I told him 34, he said no way running race gas. Said he had never seen anything like less than 38 on race gas, and yes, pump gas definitely less.
I told him these heads had been on a dyno and liked 34 degrees. He said, “ was it race or pump gas” I said pump gas, he says..see!
Goes on to say he has had TONS of motors running race gas on his dyno, and nothing liked what timing I am running.

Thoughts?
Thinking I will get a baseline at current 34 with new headers when I get car out, then start bumping it up and see what happens.
I haven’t played with it from 34, just played with jetting some, thinking 34 is kinda a default sweet spot
 
I should add, a dyno isn’t a race track, but tons of class cars, and others he has done, have been down a track.
Another point, understand these knockoff LA aluminum cylinder heads, no matter who has done them, still have lousy chambers. No getting away from that. They aren’t a W5 chamber.
so, good chambers don’t need much timing, bad chambers….might. We will see.
 
We've always seem to run 35 degree in our motors. We use a mixture of race/pump gas, but last year I switched to straight pump gas. I'd be interested in your findings. As you said a dyno isn't a race track. My father in law had his engine freshened up last year and they changed the cam from 2 degrees off (can't remember which way) to straight up. Made 10 less HP on the same dyno, but yet car is now .15-.2 faster in the 1/4 with no other changes.
 
Test test test. My race gas vs pump gas tuning generally require different jetting but timing seems to be fixed in to the engine architecture. If you are octane limited and pull timing to stay out of detonation on pump gas, then race gas will want more timing. But if you’re at max timing on pump gas and not rattling then race gas won’t want more timing. And the question becomes “why do I need race gas?”
 
TT5.9mag said:
Test test test. My race gas vs pump gas tuning generally require different jetting but timing seems to be fixed in to the engine architecture. If you are octane limited and pull timing to stay out of detonation on pump gas, then race gas will want more timing. But if you’re at max timing on pump gas and not rattling then race gas won’t want more timing. And the question becomes “why do I need race gas?”
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It makes sense to me that fuel that is harder to ignite would want different timing than pump gas. The two fuels burn at different rates.
 

550hp ish engine ran with a variety of different fuels. Every single fuel liked 29 degrees of timing. And they ran timing sweeps with every change in fuel. In this case, on the dyno, the 87 octane met the detonation requirements of the engine so adding timing made no difference in power, regardless of the fuel used. Like I said earlier, if you are octane limited with pump gas (read; timing limited) then a timing change might make more power with race gas. If pump gas meets your engines detonation requirements on full timing then no more power will be made regardless of fuel or timing used.
 
You mention a past combo. What is your combo NOW?
 
One of our engines on the dyno at westech, a 410cu in Windsor ford made more power on 91 pump than 110 Sonoco. Like 4-5 more. We started tuning on 110 and ended up blending back to straight 91 and it kept making more power. ~560hp level
 
TT5.9mag said:
One of our engines on the dyno at westech, a 410cu in Windsor ford made more power on 91 pump than 110 Sonoco. Like 4-5 more. We started tuning on 110 and ended up blending back to straight 91 and it kept making more power. ~560hp level
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A clear case of what we talk about sometimes. Using a higher octane ain't always meaning more power. lol
 
TT5.9mag said:
One of our engines on the dyno at westech, a 410cu in Windsor ford made more power on 91 pump than 110 Sonoco. Like 4-5 more. We started tuning on 110 and ended up blending back to straight 91 and it kept making more power. ~560hp level
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what compression ratio?
I can believe being down on power running something like 110 on a low compression motor
 
RustyRatRod said:
A clear case of what we talk about sometimes. Using a higher octane ain't always meaning more power. lol
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Exactly. Race fuel can effect a low compression motor in a negative way.

not what my original post is about. My motor is 12.4 to 1, requires race gas.
my point is will it like more timing than if it was say 10 to 1 running on pump gas.
 
B3422w5 said:
Exactly. Race fuel can effect a low compression motor in a negative way.

not what my original post is about. My motor is 12.4 to 1, requires race gas.
my point is will it like more timing than if it was say 10 to 1 running on pump gas.
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Yes, but NOW you tell us. LOL
 
RustyRatRod said:
Yes, but NOW you tell us. LOL
Click to expand...

Thought everybody knew..lol
i am not running race gas for my health. It’s 8.50 a gallon.
I have zero deck flat tops. I had bloomer actually mill my heads to get it to 12.4. Thought the little extra squeeze might help a heavy car.
and honestly, it’s not like I drive it 15,000 miles a year. So I live with the fuel costs
 
B3422w5 said:
Thought everybody knew..lol
i am not running race gas for my health. It’s 8.50 a gallon.
I have zero deck flat tops. I had bloomer actually mill my heads to get it to 12.4. Thought the little extra squeeze might help a heavy car.
and honestly, it’s not like I drive it 15,000 miles a year. So I live with the fuel costs
Click to expand...
That's like saying everybody knows my slant 6 build. Do you?
 
But to help add to the answer to your query, you would THINK 12.4 would not require the timing the 10 motor would, but I've found that's not always the case. Lots of factors there. Chamber shape, size, contour, whether it has sharp corners and such. Camshaft profile, piston shape. Just to name a few variables.
 
B3422w5 said:
I have locked out dizzy, running timing at 34 degrees. In fact, when I had my 13+ to 1 W5 deal, it seemed to like 32 degrees best.
Was talking to Chris Hardy at RET engine development this morning. Via a mutual friend, he and I have become friends.
I was asking him about possible jet changes going to these new bigger headers.
He asked me about timing, after some jetting tips.
When I told him 34, he said no way running race gas. Said he had never seen anything like less than 38 on race gas, and yes, pump gas definitely less.
I told him these heads had been on a dyno and liked 34 degrees. He said, “ was it race or pump gas” I said pump gas, he says..see!
Goes on to say he has had TONS of motors running race gas on his dyno, and nothing liked what timing I am running.

Thoughts?
Thinking I will get a baseline at current 34 with new headers when I get car out, then start bumping it up and see what happens.
I haven’t played with it from 34, just played with jetting some, thinking 34 is kinda a default sweet spot
Click to expand...
I'm scratching my head.. now you're a drag racer and you're using race gas now, but you never changed your tune from pump fuel. I've just gotten know you better. You would have to race the same track everytime, on the same day with the same weather, tires that never wear
..wind that never changes direction or speed. Jk
You bet your *** you can raise the timing when you up the octane. In fact you might make zero more or less if you use too much octane for the squeeze... itll just run hotter from burning slower and the timing will be far from ideal in some cases.
Gonna read the other replies now..
 
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My car with 12.3 -1 Indy 360-1 heads 705 roller and c16 race fuel liked 36 locked. And it liked 8000 RPM's. That was its sweet spot
 
MOPAROFFICIAL said:
what's the thing crank over psi?
That's a direct tell. Otherwise it be 87 to 100 octane.lol my friends 451 closed chamber bb burns 87 at 11.2 or so to 1.
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It’s in the truck and been racing for a year now. I’d have to ask the owner what cranking compression is.
 
MOPAROFFICIAL said:
I'm scratching my head.. now you're a drag racer and you're using race gas now, but you never changed your tune from pump fuel. I've just gotten know you better. Do you race the same track everytime, on the same day with the same weather, tires that never wear
..wind that never changes direction or speed. Jk
You bet your *** you can raise the timing when you up the octane. In fact you might make zero more or less if you use too much octane for the squeeze... itll just run hotter from burning slower and the timing will be far from ideal in some cases.
Gonna read the other replies now..
Click to expand...

this is a new motor, not lots of racing on it

my old motor was pump gas, long gone. Stock stroke 360
Rod Bloomer tested these heads on a short block similar to mine on the dyno, it liked 34 best. Motor was 11.6 compression, mine is 12.4( heads milled)
my only experience in my life with a good chamber, was my W5 motor. Moved timing around everywhere. Went the fastest with it at 32
my 360 that was 10 to 1 on pump gas liked 34 best, I moved it around.
thos new motor, no, I haven’t moved it around, but I don’t recall ever running 38 degrees timing in anything, but I am gonna give it a try.
and I race at a number of track, differing conditions, but as a bracket racer, you start making changes, you introduce a whole new set of variables.
if it’s 90 and 3600 feet of air, I have a pretty good idea what it will run. If it’s 70 and 2100 feet of air, I know what it will run there too.
once season of racing starts, I have never been one to change much, and unfortunately, last few years I have less chances to get out before racing starts to play around
I am busy, own a business, I don’t have tons of time to dick around, wish I did..lol
 
Don, have you considered a session on a chassis dyno?

My engine is only 11.2-1 and made the most power at 34° on an engine and chassis dyno. It also made 30 more HP on pump 93 than it did on 98 race gas, it was built for pump 93 though. You may not need as much octane as you think you do.
 
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