i have been doing some more looking and i was curious if anyone has any input on piston manufactures. SBR has some ROSS pistons which are appealing to me becuase they are 9:1 CR. http://www.slowboyracing.com/more.php?id=2141& or there are teh wisecos which are 8.5:1 CR. http://www.slowboyracing.com/more.php?id=2720& any input on brand or clearances or anything?
I have not had such good luck with wisecos, Had some issues with wrist pin design that lead to failure. Never used Ross.
I'm running WISECO on my setup right now and I am very happy with them. They are extremely light; one of the (if not THE) very lightest pistons made for our engines, and it shows: when I turn the ignition key off my engine quits instantly; not one more revolution (I have a LW flywheel too and my shortblock is JDM STI V8, so other components are lighter too). I get zero piston slap when cold and my engine recently compression tested at exactly 160PSI across the board, while cold. Not familiar with Ross, but I'll say you can't go wrong with Wisecos.
ive had good luck with wiseco...but it wasnt automotive application, jetski, snowmobile, dirtbike, ect
Wiesco pistons are very popular and the piston of choice in many of our engine builds. I am running Weisco's with upgraded wrist pins in my stealth currently. Ross pistons use to be just a spin off of JE stuff. What is important to look at for piston is material choice (alloys), design, and compression ratio. Higher compression ratio will make more power overall and increase your powerband as well as help with spool-up. Unfortunally, it will also hinder the amount of boost you can run safely on 92 octane with increasing cylinder pressures, ALSO... if you run to high of a compression ratio, you might not beable to even get the vehicle to run on 92 octane. (This is usually 10.5:1 and higher compression ratios). If you need a price quote let me know as I can hook you up on either/or.
Well i guess i have only heard of 1 person using ROSS pistons. he loves them, and says they work amazing well and run super smooth. I will need to do alot mre research. I have heard great things about mahle, but then again they dont list any options for the 2.2l on their website.
yah jason is runign wiseco. found some more info. "TWE and some ROSS pistons have an asymetrical dish that matches the combustion chamber very closely and offer lots of squish. This is awesome because you can run a higher compression ratio, get more torque and power on the same boost levels and be just as far from detonation. Or you can run the same CR and run a lot more boost and just be a giggling school girl everytime you push the loud pedal." ~ ImprezaRSX http://forums.nasioc.com/forums/showthread.php?t=964607 Know i am curious how these pistons (for an ej22t) will work with EJ20 heads.
I've had no problems thus far at ~1100 miles. No slap, only nois3s from other stuff like air filters tapping catch cans and stuff. She runs solid. I think the person boring your block matters more than the wiseco's themselves. If they don't ask for the pistons before boring, don't go through said machine shop. Subies are a bit different. The last bit needs to be finished by hand. 5th and 6th gear tunnel action here: :biggrin:
If you want to run 8:1 CR on the EJ22T with WRX heads, here is the recipe. EJ22T shortblock Wiseco 97.5mm pistons (.020 overbore) Any Std length EJ18/20/22 rods Cometic .051" headgaskets WRX heads This will give you an 8:1 CR....actually it's 8.009:1, but I think it is safe to just round down. I know you wanted to run a higher CR, Martin, but that may require you to run a different piston, something custom. The wisecos protrude from the deck .015" and you must allow at least .015" of clearance between piston at TDC and the heads. Now this gives you two options.... 1) You can have your machine shop mill the piston crown down to the deck surface at TDC. D&G motors will do this for you no problem. Already discussed it with Guy at D&G, and he said it's no problem. I also called Wiseco about milling the crown and they assured me that there would be no weakening of the piston by removing that material. You will be able to run a thinner headgasket this way, but your piston dish volume goes down. You will have to re-measure the dish volume after the milling is done and recalculate the CR. But I'm sure it'll be a little higher than the 8.28:1 CR that I had calculated since you'll be losing just a little bit of total chamber volume by removing part of the crown and reducing piston dish volume. Expect something like 8.3:1. Oh, and this is if you are using a thinner headgasket....the one I had originally planned for was an EJ22 n/a MLS headgasket available at the dealership. It was around .028-.031" thick. Which, if you tried to use it without milling the pistons you would be at risk of contacting the heads with the piston crown at TDC under load. 2) Use the Wiseco pistons as it, and run a Cometic .051" headgasket. This will net you an easy and safe 8:1 CR and plenty of clearance for stretch. Either route listed above will work. The first route requires more money (figure about 100 bucks extra to mill the pistons, but you save about 50 bucks on headgaskets by going OEM and buying it from Morries.) Oh, and make sure you have everything balanced by the machinist....you've already got everything out of the block, might as well have them balance that stuff while they got it. It cost me 150 to balance the pistons, rods, and crankshaft. Another 25 for the flywheel. Good luck Martin, sorry I haven't caught you on AIM much lately, come to Firestone and I can give you further details on the build.
^ are you going to be at firestone tonight? I would like to have a final CR of 9:1. I am not sure if this will be possible with this setup if w/ 8.5:1 CR pistons (the wisecos) you are cutting it real close to the head at TDC. I am curious if the ROSS pistons which advertise a 9:1 CR on the ej22t w/ ej22t heads will be too large and make contact on the ej20 heads. would it be possible to have a custom set of pistons made that will give me a finished 9:1 CR using he usual ej18/20/22 rods in a ej22t with ej20 heads without worries of contact at TDC?
Odds are, they have a lower piston dish volume. I doubt they would let the piston protrude from the head much more than the wisecos already do. If you can, try to call Ross and get the specs for the 9:1CR pistons, I'd need deck clearance, dish volume and bore size. If you have those values I can work with you to find out what you'd need to run for head gaskets to be safe for stretch clearance and to get your CR as close to 9:1 as possible.
i just talked with ROSS. They do not sock the EJ22 pisons, they are all custom made. so tehy do not have the specifications for deck clearnace or dish volume becuase those change per order. from what i gathered is that since they work from samples people send in, and modify the dish volume to +/- the CR, the deck clearance would be the same as a stock ej22t piston. he bore is listed as 3.834 on SBR, which is 97.3836mm. any ideas?
"Maximum Boost", by Corky Bell Page 157 "A variety of methods exist to change the compression ratio. Almost all are unacceptable. The crux of the matter is upsetting the "squish volume" around the rim of the chamber. A chamber is designed so that the charge is pushed toward its center as the piston achives top ded center. This is perhaps the strongest deterrent to detonation designed into the system, as it tends to either eliminate end gas or keep charge turbulence high. This squish volume is a rim about .3 to .4 inch wide around the chamber, and approximately .04 thick - a big, washer-shaped volume beween the piston and head. Consider "squish volume" sacred and do not tamper. It is possible to err so badly in removing squish that a resulting 7 - 1 compression ratio may ping worse than a 9 - 1 with proper squish." Thicker head gaskets are not an acceptable way of altering compression ratio.
I've got Wiseco's in my car and also in the motors I've built for others. Can't beat them for the price and no slap like JE's. Ross is also highly recommended in the DSM world but I have no personal experience with them.
