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Happy on 93-octane Pump Gas? #2000598
01/28/16 05:37 PM
01/28/16 05:37 PM
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Val-haul-ass... eventually
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BradH Offline OP
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CR: 11.12:1 --> See pic of chamber attached
Bore: 4.380"
Stroke: 3.75"
Gasket: 4.410" bore x .042" thickness
Quench: .042"
Piston config: flat-top w/ deburred valve reliefs
Camshaft; Advertised as 298 @ .020", 265 at .050", 108 LSA, 104 ICL, solid roller w/ .018" lash
Fuel: 93-octane e10 blend
Estimated cranking pressure: 190-195 psi

HughesCNCVictor72ccchamberIMMvj.jpg
Re: Happy on 93-octane Pump Gas? [Re: BradH] #2000601
01/28/16 05:44 PM
01/28/16 05:44 PM
Joined: Jan 2003
Posts: 31,260
Oregon
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AndyF Offline
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Oregon
Maybe! If it was mine I'd buy a few cans of Hot Rod 102 and start off with a 50/50 mix and then work my way down from there. Keeping things cool helps a lot so it might depend on the weather too.

Re: Happy on 93-octane Pump Gas? [Re: AndyF] #2000657
01/28/16 06:54 PM
01/28/16 06:54 PM
Joined: May 2005
Posts: 1,032
ohio
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67mprfan Offline
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ohio
You're at about the compression as me and I have ran pump gas with no problems

IMG_20151102_200152_195.jpg

71 demon stock stroke 440/indy ez-1 running 10.10 @ 132.14 mph in the 1/4 and 6.36 @ 107.46 mph in the 1/8 not in the same weekend but It did it then I sold it.
67 Belvedere that worked it's way in the 10's
Re: Happy on 93-octane Pump Gas? [Re: AndyF] #2000672
01/28/16 07:10 PM
01/28/16 07:10 PM
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Posts: 3,250
Between a rock & a hard place
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cudadoug Offline
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Between a rock & a hard place
Originally Posted By AndyF
Maybe! If it was mine I'd buy a few cans of Hot Rod 102 and start off with a 50/50 mix and then work my way down from there. Keeping things cool helps a lot so it might depend on the weather too.


What Mr. F says. But I'd bet that with that quench, the aluminum heads and the cranking pressure it will be all good.

Re: Happy on 93-octane Pump Gas? [Re: BradH] #2000703
01/28/16 08:15 PM
01/28/16 08:15 PM
Joined: Oct 2009
Posts: 1,267
North, Alabama
D-50 Offline
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My small block with Indy-2 heads, 10.9 compression and 255/266 @ .050 cam has never ran on anything but 93 octane. Cranking cylinder pressure ranged last time checked from 195-201 lbs.


1.33 60 ft,6.21 at 110.59 in the 1/8, pump gas small block,2950lbs,drag radials,mufflers and driven to track ...
Re: Happy on 93-octane Pump Gas? [Re: D-50] #2000709
01/28/16 08:22 PM
01/28/16 08:22 PM
Joined: Jan 2007
Posts: 7,664
IN
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ahy Offline
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Maybe? Things like cold air intake and a robust radiator/cooling system can help. If/when you lean on it hard... track days, road race ect. may be a good idea to mix some race gas as insurance and protection.

Re: Happy on 93-octane Pump Gas? [Re: BradH] #2000726
01/28/16 08:53 PM
01/28/16 08:53 PM
Joined: Feb 2005
Posts: 4,334
Prospect, PA
BSB67 Offline
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Prospect, PA
What is your elevation? Although the cranking pressure should say it all.

Mine blows about 190 plus or minus a couple. As low as 185 with tighter lash, but the car is quicker with the looser lash. MCH CNC Mopar aluminum head (Eddy RPM w/ straight plug). Intake closes at 77° ABDC (advertised) and 60° ABDC @ 0.050". The static CR averages about 10.85. No cylinder is over 10.9. Normally, it does not have audible ping. I had a trace of ping on a not normally used premium fuel and their winter fuel blend. Western PA.

I did valve relieve the block for both valves and made sure there was no sharp top of cylinder edge caused by the block overhang into the combustion chamber. I did not massage the piston valve pocket edges.

I do all of the other logical things to reduce the likelihood of detonation.

Your combustion chamber is so much better than mine, I would think you should be fine.

Re: Happy on 93-octane Pump Gas? [Re: BradH] #2000744
01/28/16 09:19 PM
01/28/16 09:19 PM
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Posts: 15,439
Val-haul-ass... eventually
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BradH Offline OP
Taking time off to work on my car
BradH  Offline OP
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FWIW,
- local tracks' elevation ranges from close to sea level up to around 1000', IIRC
- although the car & driver combination isn't light (3750+), it has a 4500-flash converter, 4.10 gears & short 275/60R15 tires so it's not usually "bogged down" under a load at low RPM
- 160* thermostat, fairly large radiator and a hood scoop probably help keep the operating temp w/in reason in the summer

Re: Happy on 93-octane Pump Gas? [Re: BradH] #2000760
01/28/16 09:49 PM
01/28/16 09:49 PM
Joined: Feb 2005
Posts: 4,334
Prospect, PA
BSB67 Offline
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Right. I have a tight converter and a 3.23 and no part throttle kick down and will be deep into the throttle at 30 mph in top gear pulling up a hill or accelerating out of a corner.

160 thermo, cold manifold, big rad., and -8 NGK plugs. 24° initial, but a relatively slow curve.

Re: Happy on 93-octane Pump Gas? [Re: BradH] #2000776
01/28/16 10:13 PM
01/28/16 10:13 PM
Joined: Feb 2011
Posts: 4,302
Nebraska
72Swinger Offline
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With that converter you will be golden.


Mopar to the bone!!!
Re: Happy on 93-octane Pump Gas? [Re: BradH] #2000790
01/28/16 10:37 PM
01/28/16 10:37 PM
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usa
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lewtot184 Offline
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the gasket fire ring next to the intake valve chamber wall would throw a flag for me.

Re: Happy on 93-octane Pump Gas? [Re: 72Swinger] #2000842
01/28/16 11:43 PM
01/28/16 11:43 PM
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Originally Posted By 72Swinger
With that converter you will be golden.


I agree... with the stat and the conv you shouldnt have any
issue.. I run a W-2 head with 10.6 and on the road I run
87 octane and even get on it a fair bit...at 900' to 1000'
local but in semi light car with a 5000 conv and a 4.10 gear..
I dont think you have any issues
wave

Re: Happy on 93-octane Pump Gas? [Re: BradH] #2000949
01/29/16 01:44 AM
01/29/16 01:44 AM
Joined: Aug 2003
Posts: 43,909
Bend,OR USA
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Cab_Burge Offline
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These are iron heads, correct? If not they fooled me shock If so good luck on using any pump gas less than 100 octane with that much compression in your area twocentsIf aluminum heads you may get away with that compression and pump gas without ethanol, maybe not on a hot day confused


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Happy on 93-octane Pump Gas? [Re: BradH] #2001042
01/29/16 09:37 AM
01/29/16 09:37 AM
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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BradH Offline OP
Taking time off to work on my car
BradH  Offline OP
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1. Head gasket fire ring location at edge of chamber not an issue. Same type of gasket fit exactly the same with my Stage VIs and had no problems.

2. Heads are Edelbrock Victors... still aluminum last time I picked one up.

Re: Happy on 93-octane Pump Gas? [Re: BradH] #2001048
01/29/16 09:52 AM
01/29/16 09:52 AM
Joined: Nov 2013
Posts: 597
Nashville, Tennessee
Tempest Offline
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Nashville, Tennessee
I think it will depend on your actual cranking comp, but if it's really 190, you should be fine. I ran a very similar combination with 11.6 static, similar cam and Al heads and it ran just fine for years on 92 octane.

Re: Happy on 93-octane Pump Gas? [Re: BradH] #2001090
01/29/16 11:14 AM
01/29/16 11:14 AM
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Posts: 3,698
NE Oklahoma
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Von Offline
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I cant see any reason why it wouldn't be fine on 93?


72 RR, Pump gas 440, 452s, 3800 lbs, Corked, ET Radials,. 11.33@117.72. Same car, bone stock 346s, 9.5 comp, baby solid. 12.24@110.
Re: Happy on 93-octane Pump Gas? [Re: BradH] #2001850
01/30/16 12:08 PM
01/30/16 12:08 PM
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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BradH Offline OP
Taking time off to work on my car
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Val-haul-ass... eventually
Dwayne (Porter Racing Heads) has the heads right now. I made a s.w.a.g. on the chamber volume at 74 cc, but will know some real #s soon.







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