Reply With Quote5 would be pushing it. @ 8:1 on 93, 8 pds is the limit.
How much boost can i SAFLEY run..compression is 8.745..iron heads...using 93 octane pump gas(shell)..this is a BBC 496..JE blower pistons...complete roller valvetrain..all forged components.....32* timing.....7-8lbs?????
5 would be pushing it. @ 8:1 on 93, 8 pds is the limit.
One other variable to consider would be the altitude your running at. If your racing closer to sea level you cant run as much boost as you could at 4000feet.
One other variable to consider would be the altitude your running at. If your racing closer to sea level you cant run as much boost as you could at 4000feet.
i think you mean overdrive... due to the altitude.. my blown alky motor makes 10-15 lbs more at 200 ft than it does at 4000... i know the gas motors we help with ususally pick up a few pounds at the low alt.
thanks for the replys...i am talking marine application...I ran 7lbs last year on a box stock 454/330hp gen5...always ran 93pump gas...never had an issue...ran all summer...but only turned it 48-4900 revs...yes i changed to full MSD ignition and distributor for this application
i wondered what your cranking compression is?
what stage of supercharger you use[stage 2 BDS?8-71?% overdrive?]
thanks for any info.
i wish i could hide an 8/71 under the hatch but i cant..I have a 250...that i sent to DMPE and they super tuned it....ported the cases...updated double roller bearings...new teflon on the rotors...case is true and perfect with a tight tolerance(.003)..Darren tested it and assured me it will pump 10 pounds...it pumped 7 last summer on my box stock 454/330...and was rich plug checks at different rpms...showed no signs of detenation at all...when i bored and stroked this engine to a 496...i lost 2 1/2 lbs boost and just wanna know if it would be save to change the pulley and get it back up to 7 lbs
thanks for the replys...i am talking marine application...I ran 7lbs last year on a box stock 454/330hp gen5...always ran 93pump gas...never had an issue...ran all summer...but only turned it 48-4900 revs...yes i changed to full MSD ignition and distributor for this application
That's good luck! I ran 9:1, 30 Deg timing w/ 6 pds boost, blower pistons and dentonated it to hell! 4 Pistons to be exact. I try not to run on the edge any more as I want a tad bit of room for error. Went to 8:1 Aluminum heads, 30 Deg.timing, 10 Pds now and so far all OK after one season...Runnin' on the ragged edge never paid off for me, only for my parts guys!
WOW...thats bad luck...sorry to hear that...what type blower and size...did it dedonate on a long run or what....i never held mine over a couple miles
Mine: 468, AL heads, 8.5:1, 871 spins 6100 making 11-12 lbs with 93. Charts show that I'm borderline on the 93 or race gas threshold. When I run 93, I do not stay in full boost as long as I do with Cam2 or avgas.
Posting Permissions