What are you running for cylinder pressure in them L/A's?

-
swinger340

swinger340

Well-Known Member
Joined
Jul 25, 2010
Messages
2,273
Reaction score
62
Location
Maine
What are you running for cylinder pressure w/o detonation on 91 pump gas? My recently dynoed eddy headed 340 has 182-185 and I'm wondering if it will run on 91 w/o detonation. A little worried it may run warm as well. Time will tell. Ran great on 100.
 
I've run 185 with no trouble on 91 w/10% ethanol. I think you're fine, but you may need to adjust either the timing, or jetting, or both once it's in the car running.
 
moper said:
I've run 185 with no trouble on 91 w/10% ethanol. I think you're fine, but you may need to adjust either the timing, or jetting, or both once it's in the car running.
Click to expand...
Any idea what your total timing is? My engine ran best w 35* total. It ran best w 74 P/86 S jets.
 
i got a 340 witheddys wuth bought 155 cranking , and it is super on pump gas but i know that a little lower than yours , wkat kind of power did it make:blob:
 
345man2 said:
i got a 340 witheddys wuth bought 155 cranking , and it is super on pump gas but i know that a little lower than yours , wkat kind of power did it make:blob:
Click to expand...
Made 428 HP @ 6200 406 TQ @ 5500. Thats w ootb closed chambered eddy heads. When I decide I want more ill get them ported and go w a little bigger cam. We brought it up to 6800 but after 6200 it started to drop off. Kinda pointless to over rev it for nothing.
 
I have magnum heads on my 360 with a measured 10.6:1 compression and cranking pressure in the 195 to 205 psi range.

I have my initial timing at 18 degrees BTDC and total at 33 degrees. I run 89 octane with 10% ethanol.
 
Here's 2 examples for you. My old 360 had 160 cranking and required no less than 93 octane with 18 initial and 34 degrees total timing. My new 408 has 190~195 cranking and has no trouble running 87 octane with 22 initial and 33 degrees total. Shows you how different 2 combinations can be. The old 360 was a X headed (open chambers) engine and the new 408 runs EQ closed chambered heads (still iron) with the chambers polished and the pistons at zero deck and a .038" thick gasket for a good quench. I doubt you'll have any problems running 91.
 
You must log in or register to reply here.
-

Back
Top