Turbo Buick Forums banner

Correlating Horsepower Levels

265 Views 4 Replies 3 Participants Last post by  Ormand
I got to thinking[dangerous thing sometimes],and I got to wondering if some of you guys had ever correlated airflow[grams per second] to HP level using a constant like pump gas and maximum street timing?Seems to me there should be some relation.I would think it would be helpful for guys who don't get to the track much.Any ideas?

Give em' hell!
1 - 5 of 5 Posts
I did it just for fun, but don't have the results handy. I used a rich mixture, like 12 to one, and used a brake specific fuel consumption of 0.60, as I remember. That got me about 300 hp from the 255 gps which is the max that the stock MAF will read. It also matched up pretty close with the capacity of the stock injectors. Obviously, you can get more power than that, by running leaner, using higher pressure to the injectors, etc. Probably somebody has this on a spread sheet.
Hmm.I figured that gps might correlate to ~ 1 HP per gram on pump gas at the wheels.

Give em' hell!
You can calculate BSFC. Should make things a little more accurate. I don't recall it off hand. Maybe I can look it up in the Bosch Auto Handbook.

What heating value did you use for pump gas?
Actually I believe that most all gasolines have the same or similar Qhv, but it could get tricky if you try to figure for pump gas and alky. Volumetric Eff. requires a bit of work too, and I don't like thermodynamics that much.

Actually, there might be a more 'canned' version of these calculations that you're referring to. What method are you using? equation? links? talk to me.
See less See more
I did a quick check, and the number I got for 255 g/sec is about 280 hp. I can use a little lower number for BSFC, and get 300 hp. It looks like the conversion is about 1.1 or 1.2 hp for every g/sec, maybe a little higher for those who dare to run lean, and a little lower if you run really at the "safe" end, very rich. The 280 came using 12 to one A/F fuel, and a BSFC of 0.60 lb/hp-hr.
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.