Hello all,

This type of question is usually asked in the 'all motor' forum however I decided to post it in here to see what compression most of you guys run when road racing? I'm really interested in this considering the amount of heat generated when racing over a prolonged period of time.

I'm in the middle of my build and I purchased wisceo 12.0:1 pistons. Will this be too high? I will be running a hondata s200 for fuel management. Any information would be great!

 

Are you really racing or are you lapping on a racetrack?

Racing in almost every situation requires rules to be observed and things like engine preparation and compression ratio will definatley be covered. If you are going to race, get the rules first then build the car and not the otehr way as so many people seem to do. Going back and taking off parts that you spent good money for is no good and being shoved into a much higher class because of what you have already done is not good either. Compression ration is definately regulated in every kind of real racing so get a rulebook.

If you are simply lapping the car and not actually racing, then whatever group you will run with may or may not have engine rules. If not, you are on your own to do what you want but remember that lots of power in a new car with and a non-seasoned driver will not be as fast as a seasoned driver with less car. Compression builds power and heat and costs money to build and to keep running well. There is the old adage "speed costs money, how fast do you want to go?" but honestly I can't really think of a worse idea than a 12:1 compression semi-grenade engine in an open lapping situation with an inexperienced driver.

Build a solid and reliable car and put the investment money in good tires and event entries to get more seat time for yourself. The fun part of driving on track is the driving so put your investment there and not chasing expensive horsepower to put in the hands of a novice driver.

 

Lee, thanks for the response

The car is primairly my daily driver. The "racing" aspect will come in the form of Lapping events for this season. My concern is that the actual reliability and longivity of the motor. I don't want to have to rebuild it after one or two seasons. Having said that, would it be advisable to purchase a thicker head gasket to lower the compression a little?

Your advice regarding "learning how to drive properly first" is sound and true. I do have some experience having attended lapping events locally for the past 3 years. I also don't look to be the fastest cat on the circuit at the expense of burnin my funds away.




Modified by Chillinit at 3:01 PM 2/7/2005

 

If it is simply for street and lapping, I would say to skip the sexy pistons and go with something a bit more conservative. If nothing else, at 12:1 you may be needing more octane than regular pump gas has.

My first E Prod CRX engine was a 14:1 race engine (rules had no compression limitation) that had a projected service life of just 8 hours before a recomended $3,000 freshening. I got out of that one quickly because I could not afford it. The next class was F Production which has a 10:1 compression limit which is a bit more than half a point over stock. On engines like that, I would normally try to get two race seasons from the bottom end and one season on a fresh cylinder head.

For a street and lapping car, I think you are much better off to make your car as quick, efficient and safe as you can while holding good reliability so things like improving your intake and exhaust, lighter than stock flywheel, etc. then really focussing on suspension, good brakes and tires instead of putting a lot of focus on internal engine modifications. Get the efficiencies out of the good power and reliability that you have first before just whacking on a lot of power potential with a side helping of risk. Then go use the car and smile big.

 

Do not get a thicker head gasket. It just ends up killing the effectiveness of the quench pads. If the motor is built properly, 12:1 compression should be plenty reliable. Just keep in mind that if you want to run that compression on pump gas, you will need a very competent tuner. Even then, I would still run race gas during you track events since there will be a lot of heat buildup in the motor and detonation will be more likely.

 

My Spu motor is running 13.1:1 It should be what I think is the upper limit of 93 octane.. I dont have the desire to pay $6 a gal or part thereof..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Want2race &raquo;</TD></TR><TR><TD CLASS="quote">My Spu motor is running 13.1:1 It should be what I think is the upper limit of 93 octane.. I dont have the desire to pay $6 a gal or part thereof..

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Is running or will be running?

 

The motors all together and sitting in a plastic bag.. We ran it on an engine dyno for about half an hour making sure it all worked but didnt do any power runs.. Strictly break in type stuff

The car on the other hand isnt doing too well.. Having a few space issues since I bought the new truck..