[mikes78]

Hi, I have this Lunati cam at my disposal and the site says minimum of 10.5 compression. What or how much more would be ideal if 10.5 is the minimum? Its a 350 .030 over, afr 195 eliminator heads. My plans are to run e-85 and Im buying new pistons for that fuel. I should be around 11.5-12.1 Would that be too much or will I still be ok? Either way, Im still curious what kind of compression is needed for that cam considering 10.5 is their min spec. I have a 4500 stall and this is more of a weekend cruiser/strip car so Im not worried about drive-ability and its still a hydraulic cam so I really cant expect too much anyway...LOL Cam specs below. Thanks!


Hydraulic. This is possibly the most powerful hydraulic cam ever designed! Designed for Very Hot street/bracket race applications, this cam requires a minimum of 10.5:1 compression, 4.11 gearing and 3500 RPM stall converter. Works with up to 250HP nitrous, and pulls Very Hard past 6500 RPM.
Advertised Duration (Int/Exh): 284/292
Duration @ .050 (Int/Exh): 241/249
Gross Valve Lift (Int/Exh): .525/.546
LSA/ICL: 110/106
Valve Lash (Int/Exh): Hyd/Hyd
RPM Range: 2500-6600
Includes: Cam Only
Part Number: 60105

 

[Calculated Risk]

On E85 that sounds like a good combo with compression in that range. I ran my wifes 377 on E85 this past season and it's at 14.5:1 and it responded very well. Even at 14.5:1 on a 95-100 degree day the engine will loose temp if you leave the fan on while running. I'm very happy with it, I just wish it was easier to get.

I used a wide band 02 to tune it and my idle is at .90 to .95 lambda and at wot it was happiest from .78 to .82 lambda.

 

[mikes78]

Well after doing the math I now come up with two different compression ratios. With a regular .039 gasket Im closer to 11.2 and with a thinner gasket Im 11.9. I dont have the pistons yet to determine deck height so Im using .020 in the hole at this point. With that compression and aluminum heads I believe I'm still able to use pump gas. Does this sound correct? Will 11.2 work with the cam and what would be an ideal compression target for those valve events regardless of fuel? I would really like to run E-85 but feel I need to be upper 11's or higher to do that. Sound right guys?? Thanks again!!

 

[mfret1970]

If you do end up .020 in the hole I like the thinner gasket for quench purposes. Find a piston that is close to 11:1 and run it on pump gas. Quench will be more optimal here and provide even greater detonation resistance. Still alot of variables with e-85, with pump gas 99% of the time you know what you're getting.


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