I've been a little confused about low compression pistons.Hypothetically speaking, let's say the maximum comp. ratio that the motor can handle before detonation is 18.8, and you have a 10.4 comp. motor. you run 8 psi on the motor and get 240 HP. (hypothetical) Now, you lower the compression to 9.1, you can now run 15-18 PSI, but all that will do is bring you back to 18.8. Would lowered compression motor yield more power than the stock motor at 18.8? Or can the low comp. pistons (with rods of course) handle the friction and possible detonation? If this doesn't make sense I'm sorry, but I just had to get this off my mind. I have to know if getting pistons and rods and all the labor that comes with it is worth it. Thanks in advance

Also, if I had a stand alone EMS that was tuned damned well, could a stock B16 handle the instant boost of 9 psi daily driven, 100,000 miles?

and another. Does Apex'i make a power FC for 99-00 Si civics?

thanks again

 

The more air you have going through the motor the more power you'll make. Compressing that air simply makes it burn a little more efficiently.

If you compress .25lb of air 18.8:1 you should be able to get ~half as much power as if you compress .5lb of air 18.8:1


I'm not sure if that answered it.....



[Modified by Lsos, 5:53 PM 12/9/2001]

 

So if gou go say, from 10:1 to 9:1 cr, ans stay with the same boost, you gain power?

 

a friend of mine was running a JRSC @ 10 psi on a stock B16a and he blew up the engine after a month. He did a rebuilt with 8.5:1 JE pistons and he said that he noticed a loss of power, he was running the same boost (10 psi)

 

NO if you go from 10:1 to 9:1 and use the same boost pressure you will LOSE POWER! cause now there is a greater volume (space) that needs to be filled but your using the same boost to cram air into the cylinders so you lose power.

if you go from a 9:1 to a 10:1 and use the same boost pressure 10:1 will make more power, but it will also be more likely to detonate unless you use higher octane fuel. someone correct me if I'm wrong.

 

there's living proof right there. I also remember an FMAX owner saying that he the kit without their ideal head gasket but he eventually installed it. he kept it at the same boost as before and he too experiened a loss in power. the ideal gasket lowers the compression ratio by about half a point I think. 10.5:1 -> 10:1

 

All else equal, less compression will mean less power because the mixture doesn't burn as efficiently. However, less compression lets you run more boost safely. If you take advantage of this, you will make more power.

The guy with the supercharged b16 that blew was obviously running too much boost for his engine to take it. The fact that he had no intercooler disdn't help the situation.

 

just make sure your internals can handle the extra power if not upgrade it

 

The car was 91 civic hatchback (total sleeper), with a first gen B16a, the engine was kinda old too. I drove his car and it was pulling hard. He went to the track once (with his 8.5:1 pistons) and did a 13.6 on 14 inch tires (was spining until 3rd gear) I'm sure it was a high 12 second car, he wasn't really good a the strip! eheheheh

He installed a dry nos kit after that, but didn't go to the track to try it out He sold his car about a month after. I really liked his car...