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Title: How much compression? Post by: Chris bugster on July 23, 2012, 14:26:24 pm It feels like it needs more squeeze. It has 11.6 at the moment, but the cam came up with 292 degrees at 0.050 thou checking. I would think it needs about 13:1, but I am somewhat frightened of usuing that much as it's a road car and we want to run it on 98 octane.
It's a 2332 with 48x40 cnc+ported comp elims, 48IDAs 1 7/8 exhaust, Wiseco pistons, 5.7 rods, etc Title: Re: How much compression? Post by: Shag55 on July 23, 2012, 14:51:14 pm That's awfully big cam for a road car.
Title: Re: How much compression? Post by: Shane Noone on July 23, 2012, 15:01:44 pm Hi Chris,
How you doing old chum !! ;) Don't know if this helps you any, but JMR done a lot of CR versus pump fuel testing years back ( based around 98 Octane from the pumps ) AFAIK, and concluded a CR even with a big cam of around 11.8 was on the limit. I am pretty sure I ran as high as 11.7:1 at one time but I was nervous and kept chucking Octane Booster in the Tank ;D I currently have 11.2:1 on my 2332 with FK87 and I run on either shell 98 or Momentum 99 and is fine and to be fair I even spanked her on 95 grade before and seemed perfectly ok. No signs of det. Cheers Shane. Title: Re: How much compression? Post by: Chris bugster on July 23, 2012, 20:17:36 pm Hi Shane. You getting old, too or is it just me.
The cam came up a bit bigger than expected and I should have used something smaller really for the compression we had. The cam card states that it should only have 287 degrees but when you add up all the values it comes to 294 degrees and what I got was actually 292 degrees. I have seen other guys running over 12:1 on here (The Lounge) with pump gas. Can you get away with it? |