what I see. Options

[RacerX11]

If you are worried about your fuel pump providing enough fuel, you need to monitor fuel pressure. If the 190 pump can keep pressure all the way to redline, it is adequate. If pressure drops off, the pump can't keep up. The 255 pump isn't going to allow more fuel to be injected if it is still being regulated to the same pressure. The excess fuel flow will be bypassed to the tank as long as pressure is adequate.

Fuel pressure gauges aren't very expensive. I picked up one for ~35 that attaches to the schraider valve on the fuel rail, and has enough fuel line to run it out under the hood, and placed under the windshiel wiper so you can read it while driving.

If the pressure is dropping off, put in a bigger pump. If the injector duty cycle is maxxed out, put in bigger injectors.

Also keep in mind that as you increase the regulated fuel pressure, the fuel pump won't be able to flow as much. I used to have a good link for different Walbro fuel pumps that showed fuel flow based on voltage and pressure. I will try to track it down.

Marty

[wortdog]

Unfortunately, DSMs don't have a shraider valve, you have to use a modified banjo bolt with a fitting in the top of it, or modify your fuel lines to include a T for the gauge.

This VFAQ has flowrates of the Walbro pumps that fit a DSM:
http://www.vfaq.com/FAQlocator-fuel.html

[awd4kicks]

Fuel pressure gauges aren't very expensive. I picked up one for ~35 that attaches to the schraider valve on the fuel rail, and has enough fuel line to run it out under the hood, and placed under the windshiel wiper so you can read it while driving.

Marty

You can pick up the special tapped bango bolt and a fuel pressure gage from Winners Circle cheap. I would be very cautious placing the gauge under a DSM windshield wiper though. We all know how often the wipers starts flapping on a DSM when you start banging gears! I know this from experience...I've actually washed my windshield with fresh 112 octane due to just such a calamity in the staging lanes at Cordova. Luckily I turned the ignition off quickly, nothing caught fire and no one else saw it before I got everything fitted back together. DANGEROUS!!

[RacerX11]

There are two easy solutions for the wiper problem. Either pull the wiper fuse before making a test run, or simply don't speed-shift the car while you are testing the fuel pressure. You should be able to make a pull in 2nd or 3rd gear to determine the fuel pressure situation without the need to shift.

Marty

[natedogg]

Haha! Yeah, I doubt Marcus was thinking about not speed shifting down the 1320 at Cordova. Its funny how many DSM's you see going down the strip with their windshield wipers on. Its happened to me on more than one occasion.

Don't know why, but I never thought of pulling the fuse. Now all I need is one of those fuse covers so I know which one is for the windshield wiper, lol.