Supercharger & Fuel Pressure

Reply Subscribe

Thread Tools

Search this Thread

10-10-2002, 02:35 PM

#41

MardiGrasMax

Supporting Maxima.org Member

iTrader: (14)

Join Date: Aug 2000

Posts: 4,491

Re: Re: Re: Re: Duty Cycle

Quote:

Originally posted by Y2KevSE

Weeeeeeeeeeird. Were your injectors okay at the time (dirty? clogged?)? Was this with 8:1 or 6:1?

Jane's 8:1 without Cartech:
http://boostedmaximas.com/jane97se/i...ynos/dyno3.jpg

8:1

The injectors were fine Kev, my car had only ~35k on it at that time.

I had the MEVI and put down 320whp at 6300rpms, thats the difference. Jane had ~240whp in that dyno, so an 80hp difference is allot. Some where around ~280-300whp a boosted 4g Max on stock injectors will be at 100% duty cycle.

10-10-2002, 02:46 PM

#42

dashingMax

Donating Maxima.org Member

Thread Starter

Join Date: Oct 2000

Posts: 1,402

Re: Re: Re: Re: Duty Cycle

Quote:

One should look at the HP figures and boost readings to accurately measure fuel parameters.
240 fwhp ~~> 240x1.20 = 288 bhp. (20% for automatic)
Assuming that the boost reading was 7-8 psi, the fuel pressure created using 8:1 disk would be: (8*8)+36 = 92-100 psi.
The injector duty cycle given these parameters would be approx: 75%
--- Comparing MardiGrasMax ---
3.125 + MEVI = 311 fwhp = 311x1.17 = 363 bhp (17% for manual)
On 6:1 disk pushing 10psi boost, fuel pressures would be: (6x10)+36 = 96psi. That puts those poor injectors at 95% duty cycle. Most injectors will stick wide open past 93% duty cycles, hence the need for new injectors.

When calculating I used 0.525 BSFC.
Just my 0.02

10-10-2002, 10:02 PM

#43

Y2KevSE

Rice Boy in Denial =)

iTrader: (13)

Join Date: Aug 2000

Posts: 25,357

Re: Re: Re: Re: Re: Duty Cycle

Quote:

Originally posted by MardiGrasMax

8:1

The injectors were fine Kev, my car had only ~35k on it at that time.

I had the MEVI and put down 320whp at 6300rpms, thats the difference. Jane had ~240whp in that dyno, so an 80hp difference is allot. Some where around ~280-300whp a boosted 4g Max on stock injectors will be at 100% duty cycle.

Quote:

Originally posted by dashingMax

One should look at the HP figures and boost readings to accurately measure fuel parameters.
240 fwhp ~~> 240x1.20 = 288 bhp. (20% for automatic)
Assuming that the boost reading was 7-8 psi, the fuel pressure created using 8:1 disk would be: (8*8)+36 = 92-100 psi.
The injector duty cycle given these parameters would be approx: 75%
--- Comparing MardiGrasMax ---
3.125 + MEVI = 311 fwhp = 311x1.17 = 363 bhp (17% for manual)
On 6:1 disk pushing 10psi boost, fuel pressures would be: (6x10)+36 = 96psi. That puts those poor injectors at 95% duty cycle. Most injectors will stick wide open past 93% duty cycles, hence the need for new injectors.

When calculating I used 0.525 BSFC.
Just my 0.02

You need to divide 36 by 2 before adding it to the product.