JE piston vs stock piston weight

Turbo Den · 10-15-2007, 01:47 PM

hi all,
i have a 1978 911SC w/ JE piston (3.0, 9.5:1), and trying to compete in SCCA autox, BSP class.
the class specify the piston has to be "same dimension, configuration" and weight.

anyone knows if the JE piston is lighter than stock pistons?

thank you.

RWebb · RWebb's Garage

lighter - I have posted wts. at http://www.penaltykicker.com/911/data/

which is graciously hosted by anther Pelican

2.7RACER · 10-15-2007, 02:15 PM

JE 95mm 9.5:1 piston=417 grams.
Mahle 95mm=624 to 668 grams.
Schmidt 95mm=673 to 711 grams.

Jeff Alton · 10-15-2007, 05:06 PM

My 98mm JE (10.5:1) were 424g....... Down some 200g each from the stock 95's they replaced.

Cheers

Turbo Den · 10-15-2007, 10:44 PM

Thank you for the input.
so, i am out of BSP.
now i will have to beat those SM2 monsters.

Wickd89 · 10-16-2007, 06:44 AM

Just wondering. What is the performance improvement with the reduced weight pistons? 20 more hp? 50 more hp?

What else would you replace if you swap these out??

thx, lg

David · David's Garage

My 98mm long skirt JE's are lighter than the 98mm short skirt Mahle's they replaced. Sure makes you wonder about the longevity of the JE's.

Won · 10-16-2007, 09:08 AM

Quote:

Originally Posted by Turbo Den

Thank you for the input.
so, i am out of BSP.
now i will have to beat those SM2 monsters.

I thought you were already in SM2?

cmcfaul · cmcfaul's Garage

I think the main advantage of the JE's is the increase in compression ratio.

Chris
73 911 E

Turbo Den · 09:47 AM

Quote:

Originally Posted by Won

I thought you were already in SM2?

i want to move to BSP, but i guess no more.
more realistic competition against you and Don's S2K.

btw, i found out a major reason i lost to you on Oct 13.
my engine starved for fuel in the afternoon which was much colder than the morning.
i had the same problem on last sunday driving to regional #5.

and, also, you drove better that day ^__^.

Peter Bull · Peter Bull's Garage

Quote:

Originally Posted by Wickd89

Just wondering. What is the performance improvement with the reduced weight pistons? 20 more hp? 50 more hp?

Reducing the moving mass in the engine will reduce acceleration times in lower gears, because the reduced inertia will allow the engine revs to increase quicker. In higher gears you will not notice any difference.

/Peter