It's been a while since i've turned a nut on my car, but i'm torn on what compression ratio pistons to put in my car. All my mods are listed and updated if any one would care to look.
I know for certain I'm getting Eagle ESP rods, ARP Head studs, Mitsu metal HG and new clevite bearings. My other dilema is since the 18G and 780's are in I was pondering if 8.3:1 - 8.5:1 would best suit me. I really would like a C/R that would kill lag and not grenade my motor. All of your opinions are greatly appreciated. some where down the road i was planning to run 20-23 psi as a daily driver. Cams are also another thing i was looking at but the whole emmisions thing scares me Help!

Solid

SolidBoostTSi said:

It's been a while since i've turned a nut on my car, but i'm torn on what compression ratio pistons to put in my car. All my mods are listed and updated if any one would care to look.
I know for certain I'm getting Eagle ESP rods, ARP Head studs, Mitsu metal HG and new clevite bearings. My other dilema is since the 18G and 780's are in I was pondering if 8.3:1 - 8.5:1 would best suit me. I really would like a C/R that would kill lag and not grenade my motor. All of your opinions are greatly appreciated. some where down the road i was planning to run 20-23 psi as a daily driver. Cams are also another thing i was looking at but the whole emmisions thing scares me Help!

Solid

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Does your 18g have a td05h or 6h hot side? if you have the TD05H hot side then you're spool will be like the E3 16G. I noticed virtually no difference between my 18g and my old SMALL 16G. Either way, I say go 8.5 2G pistons, if you're not planning on going past 500 whp, IMHO. Guys are handling this hp level fine with strong rods underneath, from what i've heard. They're cheap and they don't have some daily driver issues that forged pistons can have.

i've got a 5H hotside with a 7cm2 housing and with 7.8:1 it does feel like a s16G spool,
I actually wanted to push closer to the 400-450 hp range on ths turbo thats why CR choosing is critical to me right now, also they are going to be forged Ross or Wiseco slugs. I was also debating on wether gapless (total seal) rings are going to make a difference?

SolidBoostTSi said:

i've got a 5H hotside with a 7cm2 housing and with 7.8:1 it does feel like a s16G spool,
I actually wanted to push closer to the 400-450 hp range on ths turbo thats why CR choosing is critical to me right now, also they are going to be forged Ross or Wiseco slugs. I was also debating on wether gapless (total seal) rings are going to make a difference?

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WEEELLLL, I think that gapless rings really give you more horsepower because they help the cylinder keep the compression developed. I've seen tests demonstrating a 7% increase. @ 400-450 horsepower that's 30 extra! But, I also have heard reports that they can scrape too much oil from the cylinder wall causing premature cylinder bore and ring wear. It is something you'll have to research. This is just MY research. Because of MY research i'd suggest saving the money you'll spend on rings and add that to a nice set of 272s or FP2s. Cams will really get that turbo moving down the path you want.

8.3-8.5 really doesnt matter your boost is were your going to get your power from. Ross or wiesco are great choises. About the rings I would just run the rings supplyed with the pistons gaped correctly.

Also about the cams your car wont be on the rollers with the AWD they only test real emmisions on the FWD and RWD cars. When doing the emissions test our cars engine is not loaded and emmissions will always be lower so it should pass with a set of FP2s no problem with a cat.

My personal choice for pistons for a DD/ occasional strip car is Wiseco's. With your block being built the way that it already is I wouldn't put in 8.5 comp 2G pistons, although they are best bang for your buck. The reason I like Wiseco's is b/c they contain a higher silicone content which allows for faster expanding and contraction of the pistons when the temperature's change. I.E. Cold Start.

Basically all forged piston engine has potential to be a great DD, granted it is ran correctly. Initial startup of cold forged pistons is key. Letting the car warm up to at least 150* before boosting is a great way to protect the investment. Infact, some people let the car reach 180* before boosting.

well guys I've made my choice. WISECO!!!!!!!!!!!!!!!! .030 overbore!!!!!!!!!!!!!!!! 8.5:1 compression, and at the same time I ordered FP2's after all the nice comments I've heard about them like idle quality, and powerband efficiency. I've got just one last question before this thread fades out, There is a 2G 7-bolt at the shop that I work at and yes, IT
<---WALKED---> Meaning, the pistons are up for grabs (for me atleast) I'm the only DSM guy there. Do you think those pistons are salvageable?? Or would the be way too out-of-round spec wise??? I've got a set of Big rods that are naked and it would be nice to have a spare set.

Thanks Again!

Solid ^_^

[/QUOTE]Do you think those pistons are salvageable?? Or would the be way too out-of-round spec wise??? I've got a set of Big rods that are naked and it would be nice to have a spare set.

Yea those pistons should be ok. I would get new rings though. The only problem is that the 7 bolt piston pins are not the same as the 6 bolt piston pins. Im sure the rods in that motor are the big ones anyway so you should be fine.

I just had to update this thread, I changed my mind on a couple of things because of a killer discount.

ARP head studs
JE 8.5:1 .020
Cometic Head gasket .054" thick also .020
Eagle 3-D rods
FP2 cams

and more to come..........

You wont see anyone on here anymore running JEs. I would stay away from them because they dont expand as well as the ross or wiesco pistons. The low silicon content prevets them from doing so. Also look into scat rods as well.