Posted By: 1AARCUDA
500 stroker motor with 9.1 compression - 01/10/10 05:07 PM
Would a 500 stroker motor with 9.1 compression benefit from 110 octane racing fuel or would I be wasting my money? Thanks!
500 stroker motor with 9.1 compression
Posted By: emarine01
Re: 500 stroker motor with 9.1 compression - 01/10/10 05:17 PM
You need to know your cyl pressure to know for sure< compression test> @ 9-1 / 110 probably be a waste of money and loss of performance 
Posted By: jbc426
Re: 500 stroker motor with 9.1 compression - 01/11/10 08:56 AM
Is it suffering from detonation on pump gas?
Posted By: MR_P_BODY
Re: 500 stroker motor with 9.1 compression - 01/11/10 11:42 AM
Quote:
Would a 500 stroker motor with 9.1 compression benefit from 110 octane racing fuel or would I be wasting my money? Thanks!
Most likely it will hurt the performance unless it
has a detonation issue(which I wouldnt think so)... JMO
Posted By: 1AARCUDA
Re: 500 stroker motor with 9.1 compression - 01/11/10 02:44 PM
Have not fired it up yet, still waiting for parts to drop it in. What about a mixture of 93 octane and 110, maybe 2 gallons of 110 to 3 gallons of 93 in a 5 gallon jug?
Posted By: Stanton
Re: 500 stroker motor with 9.1 compression - 01/11/10 02:47 PM
Why not just 87 Octane regular ... it's a lousy 9:1 !!!
Posted By: joshking440
Re: 500 stroker motor with 9.1 compression - 01/11/10 02:51 PM
Quote:
Would a 500 stroker motor with 9.1 compression benefit from 110 octane racing fuel or would I be wasting my money? Thanks!
It would if you threw on a big old turbo.....come on
Posted By: Dodgem
Re: 500 stroker motor with 9.1 compression - 01/11/10 03:04 PM
Quote:
Why not just 87 Octane regular ... it's a lousy 9:1 !!!
if it has aluminum heads it's the same as 7.5 to 1??
Posted By: 1AARCUDA
Re: 500 stroker motor with 9.1 compression - 01/11/10 03:18 PM
Ok, I get it! Thanks for all the input. Happy Racing this coming year. 
Posted By: DJVCuda
Re: 500 stroker motor with 9.1 compression - 01/11/10 03:23 PM
what head do you have on the motor? what are the specs?
the question about detonation was a valid one and with that much stroke, and a poor combustion chamber ( open ) and no quench will result in a detonation prone environment. Race gas might be a valid solution to the black bearings you could get as a result of that combonation.
the question about detonation was a valid one and with that much stroke, and a poor combustion chamber ( open ) and no quench will result in a detonation prone environment. Race gas might be a valid solution to the black bearings you could get as a result of that combonation.
Posted By: racealittle
Re: 500 stroker motor with 9.1 compression - 01/11/10 03:48 PM
If it is aluminum heads, 87 octane will do the job. Iron heads may need 91-93 until you get things sorted.
I run an aluminum head 9.3:1 440 on 87 and it's just fine.
I run an aluminum head 9.3:1 440 on 87 and it's just fine.
Posted By: 602heavy
Re: 500 stroker motor with 9.1 compression - 01/11/10 03:49 PM
The motor will always be a pig with that CR if using alu heads , fuel 'load up' will be an issue due to the slower burn speed , i had to mill the heads fort his very reason. (600")
An earlier closing intake valve would be a band aid , although it would help , using race gas (higher octane) is a bad idea due to spark lead having to be advanced so much it will slow the piston down.
An earlier closing intake valve would be a band aid , although it would help , using race gas (higher octane) is a bad idea due to spark lead having to be advanced so much it will slow the piston down.
Posted By: Dodgem
Re: 500 stroker motor with 9.1 compression - 01/11/10 03:53 PM
Quote:
Ok, I get it! Thanks for all the input. Happy Racing this coming year.
Well the 500 inches is not the requirement for octane but the final compression, coupled with cam specs and consideration for aluminum of iron heads.
A 9 to 1 motor with a 204/210 duration cam @ .050 may need some extra above 93 octane while a 275/284 @ .050 may not need any octane above 93 and may well run on less aluminum heads generally will need less octane than Iron.
Posted By: 440mag
Re: 500 stroker motor with 9.1 compression - 01/11/10 03:58 PM
I run an aluminum heads, 496, 9.1:1 CR with 87 octane, no problem.
If I'm heading over a mountain pass I put in some 93 octane. It probably does not need it but makes me feal better.
If I'm heading over a mountain pass I put in some 93 octane. It probably does not need it but makes me feal better.
Posted By: 1AARCUDA
Re: 500 stroker motor with 9.1 compression - 01/11/10 04:03 PM
Cast Iron Stage V heads from Mopar Performance, I will have time to test and tune it in Feb, but looks like I would not need to spend $8.00 a gallon on 110
Posted By: Dodgem
Re: 500 stroker motor with 9.1 compression - 01/11/10 04:05 PM
No I would think 93 would be fine what are the cam specs?
Posted By: 1AARCUDA
Re: 500 stroker motor with 9.1 compression - 01/11/10 04:08 PM
509 lift 248 duration @.50
Posted By: DJVCuda
Re: 500 stroker motor with 9.1 compression - 01/11/10 04:12 PM
I just witnessed a 500" , stage V headed 509 cammed motor eat itself to detonation death. Black bearings were the dead giveaway.
Posted By: Dodgem
Re: 500 stroker motor with 9.1 compression - 01/11/10 04:13 PM
mild cam on a 500 but 93 should be fine. 108 lobe separation angle? degreed at 106?? start with total timing at 30 with 93 and and move up 2 degree's at a time till 36??
Posted By: Quicktree
Re: 500 stroker motor with 9.1 compression - 01/11/10 04:19 PM
Quote:
Have not fired it up yet, still waiting for parts to drop it in. What about a mixture of 93 octane and 110, maybe 2 gallons of 110 to 3 gallons of 93 in a 5 gallon jug?
you probably need it. you do know the more octane you use the slower the burn rate right? I would start with regular 93 and work your way down.
Posted By: Dodgem
Re: 500 stroker motor with 9.1 compression - 01/11/10 04:28 PM
Do a compression test hot spark plugs all out carbs off or wide open I think you will see 150 to 155 cranking compression
right at the edge for iron heads on 93.
run without vacuum advance then later only on ported vacuum tuning out any light throttle cruise ping. one place 93 is bad is guys trying to squeeze 1/10 of a mile to a gallon out with the vacuum advance 93 will not take the light throttle 46 to 54 98 to 102 octane in 68 would allow??
right at the edge for iron heads on 93.
run without vacuum advance then later only on ported vacuum tuning out any light throttle cruise ping. one place 93 is bad is guys trying to squeeze 1/10 of a mile to a gallon out with the vacuum advance 93 will not take the light throttle 46 to 54 98 to 102 octane in 68 would allow??
Posted By: DaytonaTurbo
Re: 500 stroker motor with 9.1 compression - 01/11/10 05:14 PM
Quote:Quote:
Have not fired it up yet, still waiting for parts to drop it in. What about a mixture of 93 octane and 110, maybe 2 gallons of 110 to 3 gallons of 93 in a 5 gallon jug?
you probably need it. you do know the more octane you use the slower the burn rate right? I would start with regular 93 and work your way down.
That's a lower CR but a lot of cubes with a mild cam. I would do the initial break-in with a mix of pump 93 and race gas, just to feel safe during the cam break-in and initial driving stages. After than I'd go with straight pump 93 and tune/step down from there.
Posted By: 1AARCUDA
Re: 500 stroker motor with 9.1 compression - 01/11/10 05:47 PM
I had no clue 110 burns slower, I will go with straight 93 and test and tune from there. Makes sense that my car ran slower toward the end of my season I was running straight 110, It was a 440 with 9.5.1 compression, I thought i could run better with straight 110.
Posted By: 1AARCUDA
Re: 500 stroker motor with 9.1 compression - 01/11/10 05:48 PM
What is Black bearing? Never heard that term before
Posted By: Quicktree
Re: 500 stroker motor with 9.1 compression - 01/11/10 09:22 PM
Quote:Quote:Quote:
Have not fired it up yet, still waiting for parts to drop it in. What about a mixture of 93 octane and 110, maybe 2 gallons of 110 to 3 gallons of 93 in a 5 gallon jug?
you probably need it. you do know the more octane you use the slower the burn rate right? I would start with regular 93 and work your way down.
I meant to say probably don't need it
Posted By: DaytonaTurbo
Re: 500 stroker motor with 9.1 compression - 01/11/10 10:08 PM
Quote:Quote:Quote:Quote:
Have not fired it up yet, still waiting for parts to drop it in. What about a mixture of 93 octane and 110, maybe 2 gallons of 110 to 3 gallons of 93 in a 5 gallon jug?
you probably need it. you do know the more octane you use the slower the burn rate right? I would start with regular 93 and work your way down.
I meant to say probably don't need it
Yeah that's what I figured. That's why I say he's better off safe than sorry during the initial break-in process. Once the cam break-in's done and a little driving under his belt and some tuning done, pump gas should do him fine.
Posted By: MoparDan
Re: 500 stroker motor with 9.1 compression - 01/12/10 02:09 AM
Quote:
What is Black bearing? Never heard that term before
i was wondering the same thing..
Posted By: DJVCuda
Re: 500 stroker motor with 9.1 compression - 01/12/10 12:03 PM
When I stated I just saw black bearings on a 500 CI stage V head 509 cammed motor it was from constant detonation.
This car was tuned with a AF meter and was not lean or rich in any spots - had over 30k street miles and couple hundred passes at the track.
The Black bearing was on the back of the bearing and was a dead giveaway to detonation in the motor. The black is caused by the heat.
This car was tuned with a AF meter and was not lean or rich in any spots - had over 30k street miles and couple hundred passes at the track.
The Black bearing was on the back of the bearing and was a dead giveaway to detonation in the motor. The black is caused by the heat.