Pinto Car Club of America

Ok, I've been doing some research and it seems that 8:1 compression is the bare minimum needed to run E85, and it would run poorly (as has been discussed by one of our members using E85 on his 2.0 pinto).  It seems 8.5:1 would be the minimum to make it run ok, and 9:1 would be the lowest if you want little/no loss in power etc.  An even higher compression is good though, up to 14:1 !  Of course if you went that high, you would have to run E85, gas is hard to do above 10.5:1 without some pretty severe modification.

Even more research has shown me that for a carb'd car to run it effectively, you will want to adjust your air fuel ratio.  Gas uses about 14.7:1 air/fuel, E85 runs best at about 10:1, substantially more fuel.  So if you wanted to run it alot, you would either want to go to 10:1, or somewhere in between.  The good news is that if you went to 10:1 it would still run ok on gas, just pretty rich and a little smokey.  Well, I think it would run, it would be real rich though.  I guess what it boils down to is that your best bet is to adjust for E85, or don't run straight E85.  If you mix it half and half with regular gas, you would have E42.5 and it would run pretty ok on a regular A/F ratio.