hd 10:5:1 compression pistons

[codeofdastreets]

Is anyone using wesico"s hd e85 10:5:1 compression yet.. I found out they make them for 7 bolts 92-99 engines and evo engines..Anyone know if they put these pistons in a 6 bolt motor yet?

 

[constant_proj21]

To my knowledge, they are not in the 6 bolt configuration.....but no problem there, as all you would have to do is order a custom set of hd's to your suited compression ratio. I was going to run the same piston that you are referring to (10.5 to 1, HD) in a 2.4 set up, but have since opted to not build my car up.

Plan was to run e85 (or maybe a taste of e98 from time to time), with a 2.4, MAP rods, and a fully built head. I figured a bit more compression for off boost and a 2.4 with a 35r sized turbo, would make for a very fun street car.

 

[dsmusmc]

Just have your rods machined to except the bigger wrist pins on the 7 bolt pistons. Thicker rods and thicker wrist pins.

 

[codeofdastreets]

You can put the evo hds in the 6bolt also with machining. The thing im worried about is machining a 6 bolt rod going to weaking it??

 

[dsmusmc]

Havnt heard of any problem yet. Its only 1mm just make sure you use a good machine shop.

 

[bastarddsm]

Man unless your running methanol in a race only car, I really can't a reason for them. 8:1 to 10.5:1 is only like a 3% power gain, but it has quite a few draw backs. It can cause a loss of mpg, and it severly closes your tuning window. Oh and you can't find E85? Good luck running 93.

 

[constant_proj21]

Man unless your running methanol in a race only car, I really can't a reason for them. 8:1 to 10.5:1 is only like a 3% power gain, but it has quite a few draw backs. It can cause a loss of mpg, and it severly closes your tuning window. Oh and you can't find E85? Good luck running 93.

I'm thankful to live in a state with plenty of E85, and I have access to drums of e98! The race car runs on E98, it smells like tequila coming out the exhaust... kinda

 

[1990AWD]

Man unless your running methanol in a race only car, I really can't a reason for them. 8:1 to 10.5:1 is only like a 3% power gain, but it has quite a few draw backs. It can cause a loss of mpg, and it severly closes your tuning window. Oh and you can't find E85? Good luck running 93.

I agree with everything, but the fuel mileage would go up, not down, or so I thought.

I would just do 9.0:1 or 9.5:1 max, much easier to tune and still good mileage and off boost driveability. That's what I want to do if I can afford it.

 

[streetdsmpwr]

Man unless your running methanol in a race only car, I really can't a reason for them. 8:1 to 10.5:1 is only like a 3% power gain, but it has quite a few draw backs. It can cause a loss of mpg, and it severly closes your tuning window. Oh and you can't find E85? Good luck running 93.

Where are you getting your info from? Higher compression greatly improves the efficiency of an engine, turbo or not. Above 15:1 compression is where the added friction of high compression negates the benefits of it. Also, it states in the title of these pistons("E85 series") that they are meant for E85 or any other high octane fuel, and not meant for pump gas. These would probably be beneficial for those with smaller-sized turbo's running E-85 who can't turn the boost to 40 psi and need the extra compression to give them their power goals, or for someone optimizing a large turbo setup.

 

[2deep]

FWIW, I'm running 35psi daily with pump+meth on a 10:1cr 2L motor. Even at 37psi I have yet to see any knock.

 

[forcefed86]

Man unless your running methanol in a race only car, I really can't a reason for them. 8:1 to 10.5:1 is only like a 3% power gain, but it has quite a few draw backs. It can cause a loss of mpg, and it severly closes your tuning window. Oh and you can't find E85? Good luck running 93.

Where are you getting 3% from on a 2.5 point comp increase?

It's usually more like 3% per point of raised compression NA. This would only compound with boost. Would be close to a 7% gain NA.

Out of boost driving would be improved greatly and so would spool speed. There is no reason to NOT run at least 9:1 on e85 IMO.

http://www.bgsoflex.com/crchange.html

 

[jrohner]

Manley makes a 10:1 piston, and they're only $4xx. That's what I'm going to go with. I believe the 10.5:1 rating is with the Evo head's smaller combustion chamber, and will be 10:1 with the 1g/2g head. I'm probably going to run a 1.6/1.8L Hyundai head to get mine up to 10.5:1.

More compression means more power with less boost. Great especially for smaller turbos that can't hold boost well.

Man unless your running methanol in a race only car, I really can't a reason for them. 8:1 to 10.5:1 is only like a 3% power gain, but it has quite a few draw backs. It can cause a loss of mpg, and it severly closes your tuning window. Oh and you can't find E85? Good luck running 93.

Should be at least a 10% hp gain. You should gain mileage not lose.

Not like you can compare totally different engines or setups, but VW's (and some others) run 10.5:1 with a turbo on pump premium. Dinky turbos with only about 200hp though.

 

[bastarddsm]

Where are you getting 3% from on a 2.5 point comp increase?

It's usually more like 3% per point of raised compression NA. This would only compound with boost. Would be close to a 7% gain NA.

Out of boost driving would be improved greatly and so would spool speed. There is no reason to NOT run at least 9:1 on e85 IMO.

Compression Ratio HP Determination Program

My information comes from being awesome. The power increase does not compound with boost. The extra compression increases the side loads on the piston, increasing friction.

 

[forcefed86]

My information comes from being awesome. The power increase does not compound with boost. The extra compression increases the side loads on the piston, increasing friction.

Not that I'm doubting the awesomness, but....

Compound by def means - to add or increase.

It will compound the total power produced. If you use the same formula in the link I used above and added boost your net gain would be higher than 7% (same boost levels, no other changes). The reduction of power caused by the increase in friction will be out weighed by the additional power produced until you get into much higher comp ranges. That is why the calculator states it will only work the 7-14range.

Compression does not increase flow like other mods do. It makes the engine more efficient meaning it makes more power with the same flow through it. So with higher compression to start with the added boost will be more effecient and produce more power.

Higher compression also means less exhaust dilution, which means more fresh intake charge to burn. More intake charge burned equals more power. More charge burned equals higher exhaust mass flow.

I get my infomation from books, although that was a BA statement and I appreciated it!