LESS fuel pressure

[Scot A. Sealander]

Dave Zug wrote:
> 
> George M. Dailey wrote:
> ...
> > When the FAQ is completed, line one should be:
> > Q- Can I raise my fuel pressure to inscrease my WOT power?
> > A- No. If you have a stock automobile, and its is working properly,
> > increasing fuel pressure (with no other changes) will not increase   
> > power.

I suppose the real answer (as always) should have been "it depends".  
There are a number of other varaiables involved.  On the GN list, it is 
used all the time, as the MAF is usually pegged, so it is no longer 
providing the correct airflow.   In this case, the tuning of FP can 
provide benefits.  The Syclone/Typhoon owners can easily put boost over 
the MAP limit of 15 psi and run into a similar problem, as stock it only 
has a 2 bar MAP sensor.  FP tuning can provide benefits.  I think it is 
just a baid-aid approach, but it does not cost anything!

In the case of NA cars where the sensors are not often overloaded, the 
situation is not as clear.  It will depend on the software in the ECM.


>  Second, I HAVE gotten a DEFINITE performance increse at WOT by        
> providing LESS fuel. "feels" like 35 hp or more. (as they cringe at the 
> word FEEL)
> .. not in fuel pressure, but in fuel (pulse width). i could leave you  
> guessing, but thats not productive... its on a turbo car that is made  
> FAT up high on purpose to keep from tearing up the transaxle (the weak 
> link).

In your case, GM set the boost fuel multiplier to double fuel over a 
certain amount of boost.  Less PW probably *would* be good.  Better would 
be to find the boost fuel multiplier table and correct it.  But you may 
start breaking parts....

[snip] 

> DO carmakers reduce performace for the reason of increasing mileage, or 
> do they do it more to give the warranty a better chance of making it?

I suspect it is done for warranty purposes.  


> happy holidays. :-)

And don't forget the reason for the season.

Scot Sealander   Sealand at clarityconnect.com