for all motor the choice was pretty much made . either rs machines or ycp or stock.. and it was good to go.

ive been at if for about a month now and still cant make a rational decision on what pistons to get


with the current build ive been looking at these pistons over and over and cant decide which is better.
84.5mm gsr with pro2 cams and vortech sc

I was about to buy supertech because of the price but then realized that 99% of the stores don't include rings which makes the supertech pistons same cost as other forged pistons

and its unclear if I can run ycp in this setup or not. some people say yes others say no
I cant tell
I looked at je wiseco supertech etc and some of them are just way out of my budget.

I have about 500 to spend on them. but if I can spend 400 that would be better of course so I can use that 100 to buy other parts that I still need.

anyone can recommend me where and what pistons that would work? 11-11.5CR.
or 30 compression height and 1-2cc dome height.

 

Buy used cp pistons for cheap money.

 

You should be able to find plenty of forged piston sets for under $500. Here's 10.6:1 84.5mm Wisecos for under $400.

http://tinyurl.com/kswy24f

It's a TinyURL link because the store URL was like 260 characters.

 

that's without shipping and rings don't seem to be included lol they almost got me like that with supertech too..

so between supertech and wiseco are wiseco worth the extra 100 bucks?

this is a semi daily so I don't really want full race pistons I need low expansion rate so I don't rattle every morning when I start it up. and according to many people the supertech is the only one that has that. am I right or wrong about this?

and also my block is already bored to 84.5 I red here that some brands are inconsistent with their piston to wall clearances.

 

Mahle are great 4032 pistons too but a tad pricey. Thats what my next B20 will have. I don't like using 2618 JE, CP and Wiseco for milder setups.

 

why is that?

 

Sounds like you did things a little backwards...

You are supposed to fit the bore to.the piston, not the piston to.the bore...

You may have to go up to the next oversize...

 

the cylinder walls were damaged. I didn't know what size they would come out to.
I was expecting 85mm but it turned out good at 84.5

 

if the bore is done right and pistons are machined to spec why should there be any problem

if I understand correctly the piston has the wall clearance machined into it already

so if the walls are exactly at 84.5 and piston was machined exactly the clearance should be good

 

Some parts are a few thou small or big. You usually match bore to piston to have optimal piston-to-wall clearance. You throw that flexibility out when you buy pistons post-bore.

 

well how would I suppose to do it . buy pistons in 84.5 before I know what size they gonna be?

 

Since the block was damaged you bored over till the walls are smooth correct?

Now get a bore gauge measure the exact diameter of each bore in inches and make sure they are all consistent with each other.

Call up whatever manufacturer you choose ask for the size of the piston in inches.

Then do the math and see what your clearances will end up at.

My cp pistons were all spot on with each other down to the 10 hundred thousandths .0002 +-

If you find out your piston to wall gap is wayy to big for your intended use then the only option is 85 mm

 

ok will do thanks

 

Ipg sells supertech pistons for 419$ incls rings pins etc.

 

Check out Arias pistons. Thier pistons are built to exact bore size's with the p2w clearance already set into the piston. ie 84mm piston is bored to 84mm to achive recommended p2w

 

http://tinyurl.com/kswy24f

Wiseco pistons comes with rings, everytime.

389 for a wisecos, plus shipping is a deal. Shipping shouldn't be more than 25.

 

For $400 you should be able to pickup a set of SRP's with rings....I know they're not very popular and feature softer aloys then true forged pistons however if your considering Supertechs than I take it your fine with pistons that are between true forged and cast that are typically advertised as low-moderate boost pistons.....SRP is just a alias brand of JE which you prob already know but I've heard little negative things about these and for a Vortech im guessing the boost wouldn't be any higher than 12 given the compression your planning to run....


http://www.jepistons.com/Catalogs/SR.../b20_b16a.aspx

 

Thick ring lands for limited nitrous oxide/forced induction use on low compression pistons for JE pistons

 

with the ati damper im guessing around 12 since the max boost on it is at 15psi with different combo of pulleys

 

Srps feature a harder alloy than most forged pistons. Most forged pistons people use with boost are a softer alloy, making them less prone to shattering under detonation. But they are nice pistons. Im running them in my engine. I plan on making 400hp with them, shouldn't be any issue for them.

Btw srp pistons are a 'true' forged piston. They just use 4032 alloy vs 2618 alloy.

4032 is better for street use too because of its higher silicon content, making them wear at a slower rate

 

I stand corrected....Its just that the way they're advertised due in part to the street use fact you mentioned that gave me the impression that made these a hybrid sort of piston of which is forged but from softer alloys as I always understood.

The pricing was another thing being typically $100 less with everything vs. most other name brand forged pistons however I suppose the use of silicone or higher use is why they may have marketed these this way but honestly don't see why if stronger they should be cheaper....

 

The 4032 alloy is about as strong as the 2816 alloy, but it has less tensile strength, giving it less det protection. As a result they typically dont handle super high power levels as a 2816 piston. Regardless, its still massively stronger than a cast piston. I think the tensile stength difference between 4032 and 2816 is 12%, 2816 having 12% more tensile strength

The reduction in tensile strength and power handling capabilities probably translates to companies pricing them cheaper. Im not sure if the alloy itself costs less for manufactures to purchase, but that could influence the price.

 

Now that you say it I recall having this same discussion about Supertechs pistons and since tensile strength was higher they were harder, less prone to expansion but given these properties, being a harder alloy made them less resistant to cracking because they were a less flexible alloy composition.