9:1 or 10:1 pistons

[blurred vision]

I was woundering what would be better for an apex stage 3 supercharger at 18 to 20 pounds of bost. 9:1 or 10:1 pistons. Thanks in advanced for your help.

 

[Ted Jannetty]

I was woundering what would be better for an apex stage 3 supercharger at 18 to 20 pounds of bost. 9:1 or 10:1 pistons. Thanks in advanced for your help.

Depends and what fuel your willing to run all the time.

The Higher compression will net better results as long as your willing to run the right fuel.

If you want to cheap out on the fuel you will have to go to lower compression and sacrafice some performance.

The fuel is the limiter the fuel is the limiter the fuel is the limiter!!!!!!!!!!!!!

 

[blurred vision]

How much would I lose for drag racing with the lower compression pistons, 9:1? I am going to run vp 116 octain.

 

[Ted Jannetty]

How much would I lose for drag racing with the lower compression pistons, 9:1? I am going to run vp 116 octain.

If you going to run real fuel then leave the compression in it.

I run 22 psi boost on stock motor with Sunoco Maximal.
5.2 et, 1.2 60 ft, 130 mph in 660 ft.

 

[blurred vision]

9:1

How do you think It will work with 9:1 je pistions as the motor is already built? I thought it would be better with the higher compression, but the motor builder said the sled would make more power with the lower compression, as you would get more boost or more volume in the cylnders. I still think more compression is better. I'm hoping that it will really rock in 660 or a 1000 feet with 9:1?

 

[Travis Moore]

Re: 9:1

How do you think It will work with 9:1 je pistions as the motor is already built? I thought it would be better with the higher compression, but the motor builder said the sled would make more power with the lower compression, as you would get more boost or more volume in the cylnders. I still think more compression is better. I'm hoping that it will really rock in 660 or a 1000 feet with 9:1?

You could make as much power with 9 to 1 as 10 to 1, you'd just have to run more boost to do it, plus it'd be slightly 'laggier'.

Just like Ted said, the fuel is the limiter. You'd get the best performance out of 10 to 1 and a higher octane fuel then the 9 to 1 if you can run a good fuel. If you are only drag racing, I would just leave it alone as the lag is not much of a concern for a drag racing application (espically if you are using a 2 step, nitrous, etc).

T

 

[ripntear]

22lbs. off boost with 60 shot wet nitrous stock motor C-16. It is all about the fuel!

 

[Boondockerguy]

Just a little FYI.. the JE 9:1 pistons boondocker carries have anti-detonation grooves and double pin oilers....every little bit helps..

Also we saw a 20 hp difference on the dyno from stock compression vs. 9:1...

 

[blurred vision]

Hey guys. I'm still woundering if 9:1 will be good? Should I change to 10:1? I'm running c-16 fuel. I hope 9:1 is good for drag racing and racing on lakes. I'm running 20 pounds boost. Also, how much horsepower do you think i have?

 

[srxguy]

If you are running c-16 go with more compression....

 

[HAMMER]

Courtesy of DYNOTECH
http://www.dynotechresearch.com/techarticles.asp

Boondocker GT28RS on a Stock Yamaha Apex with 9:1 JE pistons
VP C16 provided all the octane necessary to tap out the Garrett GT28RS

12.5 psi boost (pump gas safe with the 9:1 pistons for reasonable lengths of time)
RPM.........Tq.......Hp......AFR.....CFM
10300 -- 119 -- 233 -- 11.7 -- 298

13.5 psi boost
RPM.........Tq......Hp.......AFR.....CFM
10900 -- 125 -- 259 -- 12.1 -- ???

17.5 psi boost
RPM.........Tq......Hp.......AFR.....CFM
10400 -- 141 -- 279 -- 11.7 -- 353

20.5 psi boost
RPM.........Tq......Hp.......AFR.....CFM
10100 -- 161 -- 310 -- 11.5 -- 386

26.0 psi boost
RPM.........Tq.......Hp......AFR.....CFM
10200 -- 181 -- 352 -- 11.8 -- ???

 

[Ted Jannetty]

Hey guys. I'm still woundering if 9:1 will be good? Should I change to 10:1? I'm running c-16 fuel. I hope 9:1 is good for drag racing and racing on lakes. I'm running 20 pounds boost. Also, how much horsepower do you think i have?

10:1 will make more power and run better off boost and have better response.

 

[mulot30th]

on my all around rx1 blower (12psi) I have 9-1 je pistons and run pump fuel. 230hp


on my apex I run stock compression at 18psi and strait c16... 287hp