Compression?

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highwaystar

highwaystar

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How much is too much for the street? I know I am asking drag racers, and more the better usually. But where will I run into detonation problems driving on the street with 94 octane and some octane boost or occasional mix of racing gas give me problems? I am currently mocking up a short block, that with the W-2 heads(58 CC) I have, will give me 11.5:1 compression. Is this too much with the gas mentioned above and the 500-800 miles a year I drive it? Or should I take steps to get it to 11:1 or 10.5:1?

Thanks for all the advice guys.
T.J.
 
highwaystar said:
How much is too much for the street? I know I am asking drag racers, and more the better usually. But where will I run into detonation problems driving on the street with 94 octane and some octane boost or occasional mix of racing gas give me problems? I am currently mocking up a short block, that with the W-2 heads(58 CC) I have, will give me 11.5:1 compression. Is this too much with the gas mentioned above and the 500-800 miles a year I drive it? Or should I take steps to get it to 11:1 or 10.5:1?

Thanks for all the advice guys.
T.J.
Click to expand...

I had 11.5-1 in the iron headed 360 I had in my cuda. I used a MSD dial back timing retard so I could run pump gas. Performance was down with only 28 degrees total but it did run without ping. The best thing about it was when I got a load of race gas I just turned the dial back up and I was ready to go!!:toothy10:
 
I have been under the impression that 11.5 for aluminum heads and 10.5 to one for iron heads is pushing the limits of pump gas.

We only have 91 octane gas here in California
 
hemijoejr said:
I had 11.5-1 in the iron headed 360 I had in my cuda. I used a MSD dial back timing retard so I could run pump gas. Performance was down with only 28 degrees total but it did run without ping. The best thing about it was when I got a load of race gas I just turned the dial back up and I was ready to go!!:toothy10:
Click to expand...

I do have the M.S.D. dial timing, 28 total worked good huh? when you put in or mixed your racing fuel, where did you go with your timing? 35 total?

Thanks for the info,
T.j.
 
highwaystar said:
I do have the M.S.D. dial timing, 28 total worked good huh? when you put in or mixed your racing fuel, where did you go with your timing? 35 total?

Thanks for the info,
T.j.
Click to expand...

36 degrees worked best. I mixed my fuel for 97 octane with no ping.:-D
You might be unhappy with the performance with the timing turned down though. It sucks to know you have a faster car than the other guy and get shut down and laughed at. When I had some good gas I was hunting them down!!!
 
hemijoejr said:
36 degrees worked best. I mixed my fuel for 97 octane with no ping.:-D
You might be unhappy with the performance with the timing turned down though. It sucks to know you have a faster car than the other guy and get shut down and laughed at. When I had some good gas I was hunting them down!!!
Click to expand...

that's good info, I appreciate it, nice to know it worked for you through experience. What kinda E.t.'s did you turn with that combo?
Wicked Avatar pix of your Cuda, have any other pix of the car you could post?

Thanks, T.J.
 
I ran my aluminum headed 416 with 11.9 to 1 compression on the street with no issues using 93 pump gas:-D
 
I'd mill the pistons to get them at zero deck, then run the Felpro performance .039 head gasket. It makes it around 11.2:1 with a .040 quench distance. With any cam with duration over 255°@.050 you will have no issues with straight pump 93.
 
highwaystar said:
that's good info, I appreciate it, nice to know it worked for you through experience. What kinda E.t.'s did you turn with that combo?
Wicked Avatar pix of your Cuda, have any other pix of the car you could post?

Thanks, T.J.
Click to expand...
.040 over 360
12.90 @ 107.7mph
Stock 2.02 1.60 j heads
11.5-1 comp
lunati .507 lift 235dur with stock stamped rockers

I have 30 pictures in my members page, take a look for hemijoejr
It's got a worked 5.7L hemi in it now
I only have the ones below on my work laptop.

071308_09021.jpg


071308_09022.jpg


070908_19081.jpg
 
Very cool car, I like your car, I have looked at this car alot @ Carlisle. I got some pix of my own I believe. Is this it?
T.J.

DSC01514.jpg


DSC01515.jpg
 
Hope this helps -

493ci

10.8:1

34 degrees total

93 octane pump unleaded


eddy heads , flat top Ross pistons , flat tappet cam
 
What size cam are you running 496 dart?

I know, the bigger the cam, the easier it is to run pump gas with still having a high compresion ratio. But where this area is, IDK. I would have guess what Moper said.
 
old cam was a 587/593 , 259/266 -----112 cl


great freakin street/strip cam (Scott Brown design) .

i have the engine apart for new rings and thought i would go bigger on the cam.

new one is a Hughes flat tappet. dont have the numbers in front of me--but its got more lift ... 8)
 
Hell yes mr fish. Highly recommended.


:read2:



i got an un believable deal on a slightly bigger cam---im going to try it, while the motor is apart.


Believe me--i will post results 8)


that will be in april/may when it warms to 60 (i live in hell) :angryfir:
 
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