I was wondering what type of aftermarket head is better, prodesign's coolhead, or paul turners power head. My friend is thinking about getting a coolhead for his trx250r. I am thinking about getting one in the future sometime (91' lt250r). Does one work better than the other? What type of gains would you get if you put a aftermarket head on? low, mid, high, everything. Will it afect the reliability of the quad at all.

Thanks,

chuck

 

Call Duncan Racing and ask them if Pro Design makes their power heads for them. When I asked they stumbled and didn't know what to say so it made me very interested. Let me know what cc dome you are thinking about buying for your 'Racer, nobody on here really has a good answer on which size to get.

 

If I do get one for my Q racer I want one that I don't have to run race gas with only premium. So probably a 22 cc or 23 cc if they make a 23 cc.
any other info would be great

thanks,

chuck

 

A cool head will give you all around power gains, but only because it keeps your motor running cooler, and heat sucks horsepower. Its not going to give you tons of power, as on my 250r the stock head kept it pretty cool to begin with, I honestly didnt notice a difference from a stock head to a cool head.

 

Unless you are running hot, plan on changing your compression often, or really want the cool head look don't waste your money. Just have your head milled. My buddy has an R with his head milled and it works great and only cost about $35.

 

We have a few milling machines at school that I may be able mill my head with if I want to do that. Currently I am getting a new crank and bearings put in my motor and I want to see what my compression is before I do anything like that.

What compression is it safe to run on premium gas (93 octane)? I don't want to have to run race gas.
Also, how do you tell if your motor is running hot if you don't have a temp. gauge or anything?

thanks,


chuck

 

You also have to check your squish band clearance when you mill the head.

I have 170 PSI of static compression on my FL350R and run 93 octane pump gas. Timing advance also affects the octane you need to run though. I believe the FL350R timing curve is not as advanced as the TRX250R.

 

Eddie Sanders Racing also makes the "cool" heads. ESR

 

Anyone have any experience with the swirl squish bands? I am wondering if it is a sales gimic or if it really does anything. Trinity is one of the places doing it and they seem like a high quality shop.

 

I ran one of those domes in my Cool Head. It was a 19cc dome by Paul Turner I think. I was running it on a stock ported 86 cylinder at .020" with a long rod/spacer. It seemed to make pretty good power with 220lbs compression.
ERIC