351foxstang

hi,
using the calculators on this page i found the compression ratio of the motor i am buying parts for to be 11.3:1. what does this mean in terms of driveability as both a summer driver and for strip use? also is this a good number or would there be a better ratio for this type of use?
carl

schwindty

IF you have a high compression engine as long as the cam is streetable, you have to driveability problems you just have to run high test fuel all the time. I am not sure of the longevity of them as well you are going to have to ask someone else that one..... But I do know that you have to run high test all the time

StangTangGT

which sucks if its not an all track racer

351foxstang

thanks for the fast responses. i pay alot a week for fuel for my truck anyways so i doubt i will notice much of a difference between the costs of high test and the 80-90$ i have to pay per week for that. id rather pay for expensive gas and have a car that will be good on the track.
thanks again,
carl

Derf00

also to note with that compression. You will NOT be able to run forced induction (i.e. SC or Turbo) with such a high compression. As long as you keep your motor NA, you'll be fine.

351foxstang

ok sounds good. ive got eagle forged rods, stock crank and keith black hypereutectic pistons. with that setup i wasnt planning on nitrous or any forced induction anyways.
carl

88BlueGT

Yea your compression is fine for a NA car.

tinman

I can't see how you can really tell what the compression is without knowing the EXACT measurments of everything.
What is the EXACT deck hieght? What is the EXACT stroke, not just what Ford says it is. What about the cc of the cylinder head, measured volume not what somebody says it is.
Start measuring things and you could get quite a surprise.
Unless you live someplace with at least a 5000' altitude, I don't think that an 11.3 compression engine is going to be the way to go no matter what sort of gas you can get........

351foxstang

your right, i only went by what ive seen in different manuals, etc. what do you suggest for a better set up?
thanks,
carl

tinman

Where are You located? The altitude will make a lot of differance in what will run good.
Here in Arizona, I'm at 3000' static and lots of days are 5000+ air density so here you can run 10.5, no problem on pump gas premium.
Also consider the head gasket thickness. The common Fel-Pro blue is about .040 thick installed. There are gaskets out there that are anything from .021 all the way to .065 that I know of.
If you use an .021 it will raise compression over the Fel-Pro about .3 ratio. i.e.-- 10.0 to 10.3
What heads are planning to use?
Also, in Hot Rod magizine, July or August '05 there is a good artitle about pump gas high compression engines.....