turbo update no. 5.. :)... PISTONS

[Captain Slarty]

Mathew, Chun and anyone else interested.

Ok, I have been researching pistons and suitability for the turbo application (F4R 172 engine)

these are my conclusions at the moment.

Stock turbo pistons are 9.5:1 cr.

Stock turbo pistons are superbly built. They have integrated cast nickel foam inserts for excellent thermal transfer.. the 172 pistons, out of interest, dont have this.!

Head and piston form a squish area which is beautifully designed.

Squish area is the thing that reduces detonation and allows the std 172 to achieve a healthy 11:1 cr with no problems.

result.. !!

I am intending to use the std turbo pistons with about 3 cc per cylinder removed from the non squish area of the 172 head. this brings cr to about 9:1

the combination of squish helps prevent detonation.

using a forged piston, I believe, is totally unecessary due to the excellent design of the existing pistons as revealed by close inspection. Also, we are not increasing the rev limit of the engine at all.

Joe.

 

[Man-Chun]

Cool

Chun.

 

[Dash]

I was just wondering if there should be a New Captain Slarty type section for all of us techno wizards to visit when we need our fix.

 

[Captain Slarty]

lol Dash .. naw...

Btw, Mathew N Chun...

I must add, this hasnt ruled out the use of forged pistons..

the reason being - IF the 172 head cannot be enlarged - or - the piston bowl cannot be increased - safely.. (the piston could lose a mil, but not sure about the head yet)

looking at the head tomorrow..

Joe.

 

[m@thew]

this makes a change, one of your posts that could actualy save me money, Id still like to see the cost of the forged pistons though

 

[Captain Slarty]

lol...

yep, as said, it may well still be a requirement for pistons (and then might as well go forged) if the head is not easily modded.

will see, .. I will try to get some quotes after the Bank hols..