not ls1 but double your hp at 8psi?
12-03-2005, 04:48 PM
#21
FormerVendor
One thing to consider is what was manifold pressure when it was naturally aspirated?
If it had a restrictive intake tract, and was not seeing 100kpa @WOT, (say it saw 85kpa), than 8psi of boost would have been a gain starting at 85kpa, and not 100kpa.
This is one reason why hp per lb of boost gains are usually greater at lower boost levels, vs higher boost levels.
You also have to consider engine efficiency and cyl head airflow potential. I'm assuming the 5cyl engine is 4 valve/cyl? If so, it would certainly pick up more hp per lb of boost vs an older engine with 2 valve heads that didn't flow as well.
If it had a restrictive intake tract, and was not seeing 100kpa @WOT, (say it saw 85kpa), than 8psi of boost would have been a gain starting at 85kpa, and not 100kpa.
This is one reason why hp per lb of boost gains are usually greater at lower boost levels, vs higher boost levels.
You also have to consider engine efficiency and cyl head airflow potential. I'm assuming the 5cyl engine is 4 valve/cyl? If so, it would certainly pick up more hp per lb of boost vs an older engine with 2 valve heads that didn't flow as well.
12-03-2005, 04:49 PM
#22
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IMO you need to also take into consideration the amount of power being gained from the exhaust work and intake work as well. Obviously all things being equal the only way its going to double the power is to double the amount of air being taken in, but it it has an extremely restrictive intake and exhaust setup from the factory, then a lot of the power gain could be attributed to the better flowing components. does that make sense? 
12-05-2005, 05:51 AM
#24
TECH Addict
Originally Posted by MIGHTYMOUSE
if the motor was high compression to start off, and they are using race gas.
i'm thinking that 8psi boost on a car with 14:1 compression would have twice the increase as 8psi on a car with 7:1 if you can follow me there.
i'm thinking that 8psi boost on a car with 14:1 compression would have twice the increase as 8psi on a car with 7:1 if you can follow me there.
Sure same boost on a higher CR engine will produce more power. But if this had a STOCK engine then the CR must have remained constant.
If all things remain constant it will take 1 atmosphere above normal atmospheric conditons to double the power.
1 atmosphere = 1 bar or 14.7psi
however things are not normally equal, as heat and other considerations will usually degrade the achievement. Other mods of course can help even it up a little.
I think the easiest way this was done. Is by producing a relatively LOW baseline number. Maybe on a Mustang dyno on a hot day (or using correction factors to the same). It's very easy to smooth and correct the graph.
Do the mods, chuck in some 100+octane fuel slap it on a Dynojet and again pervert the correction calculations.
Thus it all looks genuine, as in reality they would have dyno'd each number. However it would still be pointless and total BS
