i know that elevation affects boost , but how much. i have an 8# pulley on my s-trim. but i only see 5# on my boost gauge. i live in reno nv. which is 4200ft. does a 3 pound loss sound about right, and if so could i swap a 10# pulley on to make up the difference. and what difference can i expect from 2 to 3 pounds of boost.
Ya, you could swap the pulley to get more boost. Just be careful when you get closer to sea level and on cooler days. You will see more boost. People do that swap all the time.
You can also add a powerpipe for more boost but a pulley will be better.
I put on a power pipe and went from 8-10lbs of boost and from 114.7mph to 119.5mph with my Novi 1000
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12.4/119.5 MPH in complete street trim
422rwhp 400rwtq on a mustang dyno
If you see 8 PSIG (gauge pressure) at sea level, then you should still see 8 PSIG at 4200 ft if the gauge measures the difference between ambient pressure and manifold pressure. But since the air density is less at 4200 ft, you'll only produce 92% of the horsepower that you would at sea level with the same pulley. I would bet that at sea level, you're gauge would still read 5 PSIG. The reason you're not reading 8 PSIG might have to do with the type of cam you're running. If you're running a high duration cam, the increased valve overlap will reduce the manifold pressure since you are basically "leaking" pressure past the valves.
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Black '99 GT , 3.73 gear, SpeedCal, K&N filter, Bullit wheels on Goodyear Eagle ZR 245/45, QA1 k-member, Granatelli front street coil overs, Steeda 555-8200R rear springs, Tokico struts, QA1 c&c plates, D&D Motorosports subframe connectors
Originally posted by atomic_stang But since the air density is less at 4200 ft, you'll only produce 92% of the horsepower that you would at sea level with the same pulley..
At exactly sea level the ambient air pressure is 14.7 psi . Thats on everything you your car , thae air going into your car everything . So yes the higher you go , the less pressure you will see . The column of air is shorter up high , you know what I mean ?
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Never argue with an idiot. They will bring you down to their level and beat you with experience...
i don't remember what the guage showed the last time i went
san diego, but the car did pull alot harder. it ran like it had another 50
horse. i'm running the frpp b-cam with 1.7 rollers.
i just ordererd the UPR boostmaster pipe. and i'm thinking about a
pulley change
Originally posted by mstng_ray it ran like it had another 50 horse.
If your car dynoed 400hp in Reno, then it would dyno around 436hp in San Diego. You'd definitely feel the difference.
Quote:
Originally posted by mstng_ray i'm running the frpp b-cam with 1.7 rollers.
I've heard both good and bad about using the b303 with a supercharger. Some say the e303 is better, some say the f303. I would ask an unbiased cam expert for their recommendation. I.E. somebody who isn't trying to sell you a cam.
If you have an 8psi pulley and are reading 5psi, then going to a 10psi pulley should get you to 7psi.
Ever try a different boost gauge to see if yours might be defective?
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Black '99 GT , 3.73 gear, SpeedCal, K&N filter, Bullit wheels on Goodyear Eagle ZR 245/45, QA1 k-member, Granatelli front street coil overs, Steeda 555-8200R rear springs, Tokico struts, QA1 c&c plates, D&D Motorosports subframe connectors
Matt, it says right on the Procharger website that the P1SC with a 3 Core intercooler will result in 12lbs of boost with 70 to 80% gain. It looks like you got around a 70% gain with your downtune.
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Kevin
74 Nova SS : 355 : Scat 4340 Crank : Manley Rod : JE Pistons : CompCam HP Nitrous Cam : AFR 195cc : Speed Demon 750 :
Originally posted by driftpin Matt, it says right on the Procharger website that the P1SC with a 3 Core intercooler will result in 12lbs of boost with 70 to 80% gain.
That makes sense.
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Originally posted by driftpin It looks like you got around a 70% gain with your downtune.
How did he downtune to get 70%?
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Black '99 GT , 3.73 gear, SpeedCal, K&N filter, Bullit wheels on Goodyear Eagle ZR 245/45, QA1 k-member, Granatelli front street coil overs, Steeda 555-8200R rear springs, Tokico struts, QA1 c&c plates, D&D Motorosports subframe connectors
Originally posted by atomic_stang That makes sense.
How did he downtune to get 70%?
Timing... mostly. If we had a higher octane gas, I could run more timing and get more power... I'm only running like 15* or 16* total timing at 6100 rpms... not much at all. Even less timing on the lower end.
But Kevin, I only have an 8 lb pulley on there... I should only be seeing 8 PSI not 12.
elevation vs. boost 
everything . So yes the higher you go , the less pressure you will see . The column of air is shorter up high , you know what I mean ?
