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View Full Version : High Compression Pistons, +32hp gain

SmackedSilly
03-05-2003, 06:49 PM
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=2405555711&category=33623

is this bull ****
im guessing it is
Jeff240sx
03-05-2003, 07:05 PM
Beck-Arnaly (sp?) is what Autozone and Discount Autoparts use to remanufacture stuff.
SOHC pistons will bump up the CR to 11.1:1 or so, so these are "custom"?
Anyway, you don't gain 10% per point of CR on our cars. Most people will agree that with SOHC pistons, you'll gain about 5% of your total power, or about 8rwhp on a car with I/H/E. Bull****, no. Think of it as an extension of the truth.
-Jeff
d240t2
03-05-2003, 07:05 PM
Yeah...32 crank hp is a little bit optimistic for a 2.1 bump in cr. 10-15whp is more like it.

Dennis
240Stilo
03-06-2003, 03:10 AM
Isn't the bore of the sohc piston a little bigger than the dohc? Just remembered digging that up somewhere, but hey if people have been using them with no problems then i see no problem.
Zemus
03-06-2003, 06:57 AM
Yea i was also wondering that, cuz i want to put my current sohc pistons in my new DOHC ka, but i want to know what i need to do
d240t2
03-06-2003, 02:59 PM
Bore and stroke of SOHC and DOHC KAs is the same
240Stilo
03-06-2003, 11:28 PM
Originally posted by d240t2
Bore and stroke of SOHC and DOHC KAs is the same

Can you please prove it just to double check, thanks:)

P.S. I was checking out how the celicas different compressions did for performance and found that the GT-S has a bigger bore, shorter stroke and 11.5: 1 CR. The GT has 10:1 CR, longer stroke, and smaller bore and the difference between the two are 40 horses and 4lb./ft. of torque. Just food for thought.
JNM240
03-07-2003, 11:14 AM
Bore is 89mm and stroke is 96mm on both. They use the same crankshaft and same rods. The pistons are interchangeable, but you do not want to put the DOHC pistons into a SOHC as you will greatly lower the CR. The 89 SOHC pistons were a 9.1:1 CR and will make a 11.6:1 CR if installed into a DOHC. The 90 SOHC pistons were 8.6:1 (lowered slightly due to changed emmision laws between 89 and 90, and also to increase driveability) and will make 11.1:1 CR in a DOHC engine. On 93 octane, 11.1:1 would be the most you would really want to run without fearing detonation.