I believe that more accurate terms would be exponential or perhaps synergistic.

another thing to keep in mind, is that the one psi to ten hp is, well generic, but also depends on the set up.

oh yeah, go to bed spy.

ha, you're still an amatuer. much learning you have in the ways of not sleeping. No sleep in over 24 hours, 233 miles down, 500 more and 12 more hours to go.

i notice your little spy eyes are off dreaming of 'double oh' my seven 34c's, where's the eighth?

but of course, my posts make no sense now. at the same time i've only hit 3 pedestrians so far and only one was on purpose.

one time i drove 21 hours straight, worked 5 hours, and then drove another three, all on 48 hours of no sleep. of course, i can't keep up with travis's habits....


maybe i'm starving for human contact. or maybe i should just change the cd, i have no idea how many times it's played through.


mmm, ju ju bee's i don't remember buying those at the gas station

The 10hp/psi is pretty close for a fairly stock car running a 14b. From 10psi to 17psi on that turbo is a pretty sure 70hp gain. Your turbo is going to feel faster at a higher psi for the same reason mine is. At 15psi your under the efficiency island of a 20g. A 20g likes 20-25psi much better than it likes 10-15psi.

There was a fairly extensive test on this a while ago. It was found that with a car modified with the basic stuff gained 7-12whp per psi. This of course goes right out the window when you take a MUCH bigger turbo than a 14b and then take it from being too low on boost to putting it in it's efficiency range.

Makes complete sense. You have to remember that psi is essentially just a measure of backpressure in the intake manifold. It's not measuring the actual quantity of air entering the engine (cfm).

So you have two factors.

1) Bigger turbo pushes more cfm per psi. More air being more hp.

2) Efficiency range. Put that turbo from say 65% to 71% efficiency while turning up the boost simultaneously and you'll have the even bigger gains. 65% efficiency of 15psi compared to 71% efficiency of 22psi is going to be HUGE.

Basicly you'll be getting more real work out of the turbo (closer to 100% efficiency) while simultaneously flowing more air per psi with that big 20G than the comparitively wimpy little 14B.

Heck, the more modded you are in terms of a less restrictive engine (better volumetric efficiency) with improved exhaust and intake paths even, the more power you should be able to make per 1psi increase.

As the engine can evacuate the spent gasses and take in more air with sheet metal intakes, better cams, and generally improved breathing, the less the compressed air should be able to 'stack up' in the intake manifold. This should give a lower 'psi' reading on the boost gauge but more real air passing through the engine.

Also, something that turbo people seem to look over is that we only go by static pressure. Airflow is proportional to total pressure. Total pressure is static + velocity pressure. Velocity pressure gives the air the ability to push the other air out of its way when it enters the combustion chamber.

These are actually HVAC concepts in regards to an air handler and duct work, but I don't see how its different.

The older NA v8 crowd talks about it as port velocity. Heads can flow bench the same or better but have worse port velocity and won't make as much power.

0-60 in 3.5! Nice!

I believe my words were exponential not geometric.

once you get more into the efficiency range of a turbo the performance will increase drastically. Until then the 10hp/1psi conversion seems fairly accurate for most poeple. this is of course, with stock heads (or Head for you 4G63 guys)

If you are referring to me I gained 26 AWHP with one pound of boost and moderate tuning. I went from 291 to 317 going from 16 pounds to 17 pounds and Ron ( http://www.axispowerracing.net/index.html ) said the Turbo was "Barely working." I'd love to see what this thing will do but I am in a very bad way financially and in other ways.The car will not be up to it's potential for a while and when it does it most likely will be up for sale.If you have any ?'s about my dyno run feel free to call Chad @ FC Customs 217-585-5080 or Ron @ Axis Power 314-865-4409. If this has nothing to do with me then ignore everything I've said.it's usually a good idea anymore anyway.

gotcha