9:1 engine specs

[RegalX2]

Was wondering about the 9:1 Stage 2 motors, how was the lower compression ratio attained vs the high comp ones. Also were the 9:1 motors on or off center and were there any 9:1 Stage 1 s ? And are the low comp pistons strong enough for turbo use ? Any other trivia appreciated.
Thanks,
Jim Turner

 

[GARY HARVEY]

Good Question!

Reference this to the BMS heads, in my case the motor is ON/C.

Special Order Piston was required to get 8/1 and I'm not too sure who makes them, since the lower comp piston never crossed my mind.
Stage One 9/1 guys answer that part of your question (i don't know).
What I noticed; the heads were in the 44 CC area (typical I'm told) and (in my case) pistons (JE) and the resulting combination ended up in the 9/1 region. Why? The SB was complete (when I bought it) and I had to live with it and simply was not interested in the (added) expense/trouble of what IMO is a non-issue. Running a touch less boost is a easy way of getting around the situation . Besides 9 to 1 does make for a snappy setup and the S2 has no problem living with the extra press. with current engine control systems.

IMO there is no trivia when it comes to putting together an S2.

Knowing what you want is the way of saving yourself lots of agony (and Money).

Asking quesion's is the only way.
gary

 

[Reginald West]

I just finished my 9-1 stage 2 off center project.I had to order CP Pistons to acheive the the 9 to 1 compression ratio. I have not ran it at the track yet,we have had some dyno time and it looks promising.


REG

 

[Mac in SD]

Just FYI - I put my low-buck on-center stage 2 together with 9:1 CR. That's a 4.020 bore, 3.590 stroke, 6.5 inch rods, 42 cc S2 heads. The pistons are used Diamond's out of an ASA motor. My best measurement of the piston deck thickness was about .240, which is less than the .250 recommended for turbo pistons. But, since I'm not running high boost for long periods of time, and I live by my knock detector religiously, it's holding together pretty well, I think.

I can run around 13 lbs boost on 91 octane - which is plenty on the street, trust me.

 

[RegalX2]

Just got the spec sheets on this motor today, turns out it had been detuned by a local shop that built many Busch North motors, anyway they put in JE's with 39 cc dish to get 9.56 :1. for a sand drag Jeep. Its a 4.020 X 3.590 6.5 Carrillo combo, I dont know the deck height or head cc's yet. Seems a little high
Thanks for the input everyone.

Jim Turner