Paul V S

hear hear!
excellent work. i agree, even more impressive than the herculean hp/trq #'s is the sharing of information as the great experiment unfolded. thank you cjv and congratulations!

Konstantin

Motec sugest a high capacity Bosch fuel pump for the 911 but I am not sure if it fits inside the tank. You may check it or you may need two fuel pumps. This would be better.

Konstantin

Sameer

Chad,
How does the Gemballa 854 bhp get enough fueling? Hope this helps.

Sameer

Chad,
Awaiting the good news. Your thread to me is the most interesting. I look forward to your bigger horsepower numbers. Keep us posted on the outcome.

Sameer

I think fuel cell themselves sell their products outright to the customer.

caneaddict

CJV
Could you mention the things you have done to shave weight on the car and anything you are considering doing in the future? Also have you considered widening the back end like the Ruf car that has recently been mentioned in order to fit wider tires?

Konstantin

if you cant find one Pump that is big enough and works ok at low speed then two smaller pumps will be betetr. easier to find and will work on lower speed ok.
It is like the injectors. some of the big ones do not works nice on low load.

Konstantin

Cary

Holy crap!!! Just the intakes for the turbos are over 60 pounds?? Or were there more tubes than the $2400 one you just put on. That is fantastic. Do you know how much your car weighs right now?

Have you taken out your rear seats? I found those to be surprisingly heavy and easy to remove. I also took out the sunroof and rear wiper which was a slam dunk compared to earlier 911’s. The only thing was it only took out about 25 or 30 pounds total.

If you do get an itch to do the 335’s again, I just saw my rear quarters the other day and they look very cool. As soon as he finishes the fronts I’ll post a pic if you’d like.

Ruf-Racer

Chad,

We certainly look forward to your visit! Nevada SH93A @ Wendover is a perfect road for a warm up in June! Go to: <a href="http://openroadracing.com" target="_blank">openroadracing.com</a> for rules and requirements! Fuell cell is certainly a giant step forward! I will mail cetain details for preparation!

R

<img border="0" alt="[cheers]" title="" src="graemlins/beerchug.gif" />

johnfm

Chad

congrats from a humble 964 owner!

Re fuel pumps, you mention a high capacity race pump in line AFTER the tank - obviously this can't be downstream of the stock pump!

Look forward to the new numbers with the bigger pump fitted.

Good luck!

johnfm

If the existing pump has a max flow rate of X l/min (or cc/sec or whatever units you like), this system should only work if the outlet pipe diameter has a significant effect on the max throughput of the pump.

If stock pump can only pump X, but your engine consumes 1.5X at full throttle, the bigger pump will make no difference.

I can only assume the stock pump is being limited by outlet pipe diameter. Sounds odd to me!!

I would have though the best solution would have been to either bypass the stock ump altogether or, feed the second pump separately & use the second pump to augment stock pump flow at WOT.

Still, if they say it works, it probably does!!

Maybe JimBob can make sense of it??

JohnM

Re fuel pumps, the problem for the stock pump is not the outlet diameter but its inability to deliver the required flow rate at the fuel rail pressure - the pump is working into a load, in effect. There will be a back pressure at which the pump flow drops to zero, whilst the pump's maximum flow rate will occur at zero pressure across it. Using pumps in series lowers the presure differential across each so the flow rate goes up. This is very common in motorsport applications with high fuel rail pressures, typically a relatively small electric intank pump will be supplying the fuel system's main engine-driven mechanical pump, keeping a (relatively) small positive pressure at the mechanical pump's inlet - without the intank pump cavitation can occur at the mechanical pump inlet as it tries to create a negative pressure, which is a bad thing.

johnfm

JohnM

thanks for clarifying - makes perfect sense.

BTW, are you a tuner? If so, where in the UK?

JohnM

Hi John,

I'm not a tuner (though I've mapped a few engines in my time ). My (relevant) background is in design and application of engine and chassis management systems and components for, shall we say, "big budget" motorsport applications.

bigsky

Excuse my ignorance, but isn't this in effect creating the equivalent of a two stage pump. The first in-tank pump increases the pressure which acts as the relative baseline pressure for the second higher pressure pump.As long as the first pump can support the volume the overall pressure will increase greater than either pump alone.
Rob