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#1
10-24-2003, 04:18 PM
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Has anyone seen more than 100%?
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#2
10-24-2003, 04:18 PM
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Has anyone seen more than 100%?
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#3
10-24-2003, 04:54 PM
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#4
10-25-2003, 07:37 PM
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 I stay'n up alnite read'n past post and i found a couple of guys state'n they had a figure of 107% with D-Ports on the Dyno, but they didn't say these bracket racing engines or all out to prove a point! I also found out that a stock D-Port intake volume of 164 to 168 was increased to 183 cc's.....Thats still small! One guy ststed after port'n and test'n D-Ports he installed stock out of the box E-Heads and picked up 30 HP!! Looks like for the average guy its a better deal to just go E-Heads.......I seen where Edelbrock tested a 467" with there heads and got 116% VE........I know my friend went from 10.83 at 122 mph to 131.00 at 10.125 with just a head change.......Looks to me that if your not CLASS racing the time and efford isn't worth the end results...........Thanks for all the info.
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#5
10-25-2003, 08:47 PM
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Someone already said that the VE number most times was a calculation after the fact. I agree.
Depending on the motor, the dyno cell, the equipment to accurately measure the ring blow-by and the exhaust leakage can have a effect on whether the calculation is performed correctly. With an optimized intake system and the engine held at a tuned rpm like say 7500 rpm, it is conceivable that you could have over 100% VE Naturally aspirated. Change the rpm by 500 rpm and all bets are off as typically the tuning effect is only positive in a very narrow rpm range. With a boosted engine there is no doubt if you are over 100% ve but even that calculation of pressure ratio vs actual air charge density can be inaccurate. Cylinder pressure readings are the best indicator. Tom V. 
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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#6
10-25-2003, 11:09 PM
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Tom V : I like your answers. most of the time they are over my head, i'm just an ole old farm boy... i know figure'n on paper or these computer things are not like the real thing but when you do the math just to get pallpark figures if you leave out the VE% the Hp never comes out close. just my .02.... On the cylinder pressure: our most Pontiac bracket motors: Runn'n 225 lbs sound about rite or should i be see'n more......E-Heads-463" 259-269 Solid Roller- 11.8 compress.....Joe
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#7
10-26-2003, 09:26 AM
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Your 225 number is probably from a compression test.
I was speaking of running numbers like 80 BAR or 100 BAR which is 1160 psi to 1450 psi when read at the combustion chanber through a spark plug pressure sensor. The 100 BAR number would be a Boosted Engine type number. All that aside, a lot of your reading depends on the cam profile vs the static compression ratio. Some of the old Super Stock Pontiacs used to have low cylinder readings that suddenly got a lot better once the engine was actually running. Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
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