Piston For Tw 170s Around 8.5:1 Compression

Discussion in '1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-' started by TOOLOW91, Feb 18, 2014.

  1. Can anyone point me in the right direction of what piston would be best for 10-12 lbs of boost and work with a tw head . still considering all my options and assembling the motor myself isn't out of the question.

    The cam will be a lunati 218-228 .536.536 112LSA . Everything i see on CHP is like 8.2:1 with a 60cc head in the twisted wedge pistons. Others are 9.5 which seems to high ? Any insight from the experienced guys here? I would really like to run a 306 with those heads and this cam . The cam is almost identical to Andersons blower cam
  2. 8.2:1 is way too low of compression in my opinion. We just had a car that was on the dyno with an si kit that was 10:1 and made some silly power too much for the stock block lol. I would ideally like to see your compression at 9:1. If you don't want to go with a custom piston which adds alot of expense then you could opt for the 9.5:1 piston and use a thicker cometic head gasket to lower to compression. With a .041 gasket my motor would have been 10:1 but with a .066 gasket I'm at 9.6:1 In my 91GT I have .120 gaskets to get the compression down to 9.5:1 since the heads have been milled so much.
    A5literMan likes this.
  3. what about detonation at that compression 9.5:1 is ok still? i am not looking to run meth on the car or anything
  4. A flattop probe srs will yeild me 9.4:1 with the head gasket felpro 9333pt1 it should be perfect no?

    and the reason for the cheap gasket is that id rather it eat a gasket and give me room for error then have a major catastrophe. i want this motor to last at least a few years.
  5. You should be fine. Just start conservative on timing,fuel,tune etc.
  6. It's all in the tune up. Higher compression just leads to more cylinder pressure which yields higher hp. You will make the same power with less timing with higher cylinder pressure. You will surely be able to make enough power with this combo to split a stock block so timing will be conservative anyway. Any good tuner will know and recognize the detonation thresehold and keep you safely away from it. At 9.4:1 you will be fine however I wouldn't mind it being a bit lower. If you don't already have the headgaskets just look to spend a few extra dollars on a better set of Cometics or MLS type gaskets to dial in the compression right to 9:1 if possible.
  7. Will do. And Kris is 99.9 percent the guy tuning it anyways so i am sure we will be ok here.

    @84Ttop and i am not opposed to buying the gaskets. How thick though do i need to be? I m a real noob here
  8. Sounds good!!
  9. Which cylinder heads do you have?
  10. looking to order TFS twisted wedge . the only head gasket I seen cometic have close to stock would be one for an AFR . I wouldn't be opposed to ordering an AFR either if that makes thing a easier just a few hundred more .
  11. Is there a reason the motor needs new pistons? Can you just run the stock bottom end with maybe some fresh rings and bearings?
    2000xp8 likes this.
  12. @NIKwoaC I haven't opened the motor up but I was gonna just throw a set of pistons in it , is your vote to re ring and bearing it and call it good ?
    MY 85 GT likes this.
  13. That's my vote. If it aint broke....
  14. Jeff mine has the stock lower block stock pistons with almost 100,ooo miles sure im sure I push it but hell I push it on a stock block anyways I would re-ring you stock block..i mean like Nick said your going to make enough HP to split that block into pieces why spend extra money on really good pistons and still have a stock block..im no one to tell anyone what to do being im running 14 psi with my turbo set-up...yes I do run meth injection I use ARP studs and fel pro 9333 pt1s the reason I went with them was when doing my build I heard people saying the cometic gaskets were stronger then the blocks...lol..I wanted a fuse...if you know what I mean....
  15. Oh Yeah Jeff I run the TFS 170 heads also mine are not out of the box ones tho..mine are fully worked bowl blended,better valves,ported and polished...etc etc...I bought them that way I got a great deal on them...I like these heads..they do have a tendency to make more noise at idle sounds a little like a sewing machine..lol..but that's ok..thats because the stud mounted not shaft style...I still even run the stock cam...lol...car makes tons of power and drives mostly like stock until you hit the go pedal....
    85rkyboby likes this.
  16. Yeah I agree with you guys totally I am gonna open the motor Saturday if all is well that's the plan and I am hoping with my cam it should still clear the pistons as it al almost the same as a tfs1 it has less duration and a little more lift . and I bought the 9333pt1 as you said cuz somone else suggested a fuse
  17. Yeah I did a lot a lot a lot of research before I went turbo I knew the cometic heads gasket or MLS are better but not for my stock block...LOL I wanted a fuse...I think you will be good..let us know...keep us updated...
  18. Oh I definitely plan to it's just nice to have a lot of experience and opinion from real world results before I make a move
    85rkyboby likes this.