I don't know if you guys know this or not thought i would just throw it in...Crate engine depot has full race pistons for the 2.0L ecotec for $783.13. it says it boost the compresssion up to 10.5:1. Isn't that what they did when gm performance built that lsj motor?

 

can you run that CR with the boost? and the rest of the moter stock?

 

its for drag racing only. as in track cars.

 

I thought lower compression was better for F/I cars

 

Stock compression ratio is 9.5:1 on the LSJ engine. We are an M.W.D. (Master Warehouse Distributor) for Diamond Racing, and are working with them now on releasing these to the general public. It won't be long...

 

yeah, i thought lower compression was better for our supercharged cars.

 

I, personally, think the LSJ would benefit some w/ a compression ratio of 10.0:1, I wouldn't go any higher though. A higher compression motor is going to have far greater torque and low end power as the boost is only starting to come in, vs a lower compression motor that is going to basically relying soley on boost to create power. You don't want to go too high of a compression ratio or the useable boost from a supercharger would almost be negated (that and the effective compression ratio would be way out of the boundaries of a streetable motor). From what I understand you want to have a nice balance between compression ratio and boost while maintaining reliability. But anyway, this is usually the case w/ motors running 8.5:1 compression or lower...the stock compression ratio is fine for the LSJ, but IMHO I think 10.0:1 w/ forged pistons the LSJ would see a nice bump in power while maintaining the same boost level.

 

a higher compression, forged piston is fine for streetable use as noted in the build book as being reccomended for over 300hp applications. changing the pistons would not make it unsable for daily drivability

 

excelent!

any idea when these 10:1 pistions are goin to be avalible? any idea on price?

 

They are available now from Crate engine depot.

 

absolutly. Once you get past the efficiency of the stock SC, you have to start looking elsewhere for power. Either a larger SC, turbo, timing or compression.

Pretty much the only way to get 400+ HP out of a grand prix is by swapping in the higher compression NA engine with the SC top end. GTP's have 8.5 compression stock while GT's have 9.4. This extra .9 compression does wonders. Once real mods start to come out (and people actually buy them) like cams, header, ported heads, etc then the pulleys will get to a point that all they produce is more heat. So youre left with trying to get power other ways.

If youre planning on keeping the m62, i would think raising the compression would be a great mod. 10.5 might actually be doable, but like everything else, someone needs to be first.

 

You're absolutely right, the only problem is that the trail and error thing can cuzse blown motors. hopefully an actuall shop will test this out.

 

not if you stay with a conservative pulley. On GPs at least, when swapping to a high compression engine, people usually drop .1-.15 sizes in pullys. Since 3.0 is basically good stock, say you had headers, piggyback, intake, and catback, then add high compression just drop back to that 3.0 scan and go from there. If you dont have any KR, then drop more pullies till you do. You just cant expect to run higher compression with the same pulley unless youre running a much higher pulley than necessary.

 

If we can use a smaller pulley with stock pistons, then we should be able to use the 10.0:1 or 10.5:1 pistons with the the stock or larger pulley. That would allow the same amount of pressure in the chamber with less drag from the s/c. Yes...no?

I think my theory is correct...larger pulley = less drag. High compression pistons make up for the lack of boost from the s/c. Net out come = more power to the wheels.

 

Stuffy is right.

And yes, going with higher compression will let you drop to a smaller pulley to keep the same power. Which means less drag and less heat. Its a win-win situation.

With the M62 already maxxed out at 2.7" pulley @ like 6k-6500rpm. Once you raise the shift limit to 8k, and raise the compression, you'll be fine with like a 3.2" pulley, and probably still making the same power.

 

I think getting the higher compression pistons is a good route for those who "max out" the stock blower, but can't afford a larger blower.

 

thats true i mean it would be less work for the blower, less psi to make power. and i'm thinking the guys who are going the intense racing stage 3 route will need to upgrade there pistons if they want to upgrade more.

 

I can't seem to find these diamond pistons that the folks @ Intense said they will be selling. The set on crate engine depot is too much of a compression bump, I want 10.1:1 not 10.5:1.

 

I have a spare lsj from a wrecked redline and I am working with saturn motorsports and a few other companies on better internals. By this I mean h-beam eagle rods, forged pistons, better valve springs, cams, ported heads and ported superchargers. These will take a bit of time but it is in the works. I just recieved the longblock and I am in the process of disassembly and shipping the sample peices out for measurement. As soon as I get word I will post progress.

For other info check out the www.****************** I use the same name over there..

 

good deal! Thanks for the info Sinister! One of my good friends does port work on LS1-2-6 and 4.6l ford heads...I would love to have him port the LSJ's...but I can't afford to have my car down for a few weeks..ugh. Anyway, good to hear someone is going to get some info on that!

 

i know they bumped up the compression on the 300hp build book, but with roots blower when you can have boost anywhere on the rpm band, why would someone want to do this? it's not like we need anymore torque on the street becuase 1st gear is useless anyways. i think the stock compression is perfectfor our setup

 

You need to bump the compression when you max out the blower. There will be a point where you can't put a smaller pulley on the blower because spinning it that fast will make the air to hot and/or useless.

So if you bump the compression some, you can put on a smaller pulley and still make the same power. Plus the blower will be spinning slower, generating less heat.

 

Our intial offerings will be 9.5:1 and 10.0:1 for compression. Because of the coating you probably will not need to raise pulley sizes from your current setup so you can take advantage of the extra compression and not have to sacrifice power going to a larger pulley.

I would anticipate these being available in mid January.

 

are there any price estimates yet? and what coating would you be reffering to?

 

Great! Thanks for the info.