Spawne32

iTrader: (3)

hey guys, wanted to know if anyone has any experience with YCP vitara pistons. Looking to use these in a supercharged b20 setup, i wanted between 10 to 10.5 compression. These pistons fit my budget and from what ive been hearing are of decent quality along the lines of nippon and rsmachines.



I cant find any part numbers on the YCP website or any information on the ebay listing i was looking at about dome or comp height so that i could calculate the compression ratio after all my milling and such on a 47cc chamber volume head.

http://cgi.ebay.com/ebaymotors/ws/eB...category=33623

SR20S13

they are modeled after USDM ITR pistons

Spawne32

iTrader: (3)

so that puts them at 11.36:1 before milling according to the calculator, which is too high for what im using them for, they dont make them in any other compressions do they? because if they were USDM B18C1 spec they would be perfect.

SR20S13

nope, get forged pistons is all I can say

EsotericImage

iTrader: (8)

nothin wrong with some cast pistons..

racebum

stock b20 pistons? i mean unless you sleeved the block those cylinders will distort if you bring the hp up too much.

not sure what the auction is BS'ing about semi forged. you either forge a piston or you cast it. there's no semi

Spawne32

iTrader: (3)

its heat treating, i wouldnt exactly call it forging either

racebum

LOL

heat treating has zero effect on a cast part. cast means just that, they have liquid metal they pour in a cast. it's about as hot as can be when the piston is made

Spawne32

iTrader: (3)

http://webpages.charter.net/beckracing/page04.htm

http://en.wikipedia.org/wiki/Hypereutectic_piston

double check your facts

wmac

for d-series vitara builds, YCP is the brand of choice.
Speedfactory used them for a 500+hp build.

Spawne32

iTrader: (3)

yeh they seem to have just as good of a rep as rsmachine pistons, but i cant find catalogs, or places that sell them anywhere to find out if they have what i need, i dont want to be above 11:1 on this jrsc setup

racebum

don't buy it. would like to see actual strength tests. cast pistons are as melted as melted gets when they are made. heating them and rapidly cooling for the seperation? maybe? but it's more work, more cost and still isn't anywhere near a forging

racebum

don't buy it. would like to see actual strength tests. cast pistons are as melted as melted gets when they are made. heating them and rapidly cooling for the seperation? maybe? but it's more work, more cost and still isn't anywhere near a forging

it's not because alloying the metal with silicon or heating and rapidly cooling doesn't have effect. it's that increasing hardness brings along an increase in how brittle the metal is.

Spawne32

iTrader: (3)

the purpose of heat treating is to allow the molecules of the metals to realign into a stronger shape, thats accomplished by a series of heating and cooling cycles, this can be done on any metal alloys, cast pistons vs forged pistons is part of the CASTING process, not the heat treating process.

all cast pistons and forged pistons are all formed the same way, the difference is forged pistons are made with a hydraulic press to evacuate any porous areas in the liquid metal. like i said do some research on it, a simple wikipedia search about metal forging and casting and heat treating will explain the process.

SovXietday

Supercharged B20 setup?

I wouldn't worry about much of anything.

turbohatch96y7

iTrader: (15)

Thanks for the link. From what I got from that is all pistons start as a cast then for added srength are forged by compressing the alloy together making the piston stronger. Stock motors use cast pistons because their properties are strong enough for everyday normal driving. You upgrade to forged when you increase the cylinder pressure (boost). To help resist against detonation and knock. You learn something new everyday even at 2am lol

EsotericImage

iTrader: (8)

lets not forget quench pads and other properties are also a factor.

I have looked for 84mm cast for a future B20 build. I looked into forged, but i like the low expansion rate of cast.

Spawne32

iTrader: (3)

forged pistons actually have the lower expansion rate, thats the reason why you will commonly hear about piston slap on a cold start with a forged piston, because they dont expand rapidly when heated. the molecules of the metal are actually bonded much tighter and held together in much stronger chains then that of cast pistons, not that cast pistons are weak but forged is as strong as you can get. Then there are the other various aspects of metal working for pistons like heat treating and other types of alloys which alot of forged pistons use to their advantage as well, and tend to vary from manufacturer to manufacturer. The best heat treatment you can get is cryo-treating, which is a sub zero cooling and heating cycle for maximum strength increase. Where as T6 heat treating is more of a rapid water cooling type of treatment.


My main concern if i do buy these is the compression ratio with the low boost setup, if you dont know already ill be 10psi or less on the JRSC setup, so im not sure if slightly above 11:1 compression is gona cause a problem in boost. Even though type-r motors work fine with the JRSC kits however.

bgdriver

Vitaras don't work in b20. 75-76mm bore.

Hidenplanvew

YCP pistons are pretty good, I ran them... They do sometimes crack but are pretty good for cheap and much stronger then stock pistons.. The T6 treatment makes them strong enuff.. I wouldnt run High boost on a b20 all together since they have the thinner cylinder walls. At alittle over 11 to 1, I would run E85 and you should be ok...

racebum

where are you getting some of this stuff? forged pistons expand MORE than cast. a typical cast honda piston sets up at .0015 where as a typical 4032 forged piston sets up at .0030. if you installed a forged piston into a .0015 clearance it would seize or scuff the **** out of both it and the cylinder when it's hot

Hidenplanvew

Also depends on if its high silcon, or low... High will not expand nearly as much so you can run closer P2W, but they are less forgiving to knock or pre det. Low will be a softer piston so its more forgiving but you do need to run a larger P2W.

T6 is cast but much stonger, with higher compression T6 I wouldnt run nearly as much boost but you wouldnt need as much boost to have fun. Dont expect like 400 hp OP I wouldnt pushing it much pass 300whp

Spawne32

iTrader: (3)

oh i dont expect 400hp at all, its barely a 10psi setup on a eaton m45 supercharger, maximum of 300hp if im lucky.

Turbo-LS

iTrader: (4)

Forged expand slower than cast and the higher the silicon (not silicone) content of the metal the slower & less it expands. Allows for tighter ptw and still very durable. Ive been runnign SRP's for a couple years now in my stock sleeve gsr and love them. there quiet when cold and handle alot of abuse 400+whp no problems here

racebum

i suppose if the rate of expansion was a concern?

final numbers are all i've ever thought people were concerned with. you're right though, 4032 is an awesome street piston since you can run pwc barely over cast and have a much stronger piston