I've always read that the 190lph is enough to max out 550's.

When I added the fuel pressure gauge I found the I was losing fuel pressure at higher RPM's with 190 pump and the NT FPR. I added the bosch in line pump and problem solved and the car ran great. I don't have the pump anymore. Travis may still have it. So I say yes it is possible to max out a 190 pump on a 14b/440 car. Do you have a NT FPR in there? Do you want to try one?



Darryl

Let me see if I can find it this evening.


Darryl

Agreed. Marcus always seemed to be running out of fuel in the higher RPM's when he was running the 190 as well. 255 is the way to go. Almost makes you wonder how DSM got away with running an underpowered 90 lph pump from the factory.

i get bad cut out in the higher rpms
i have STOCK injectors and a 190lph walboro
is it cause of the STOCK injectors??
what route should i go guys, it is a stock 14b with a 2 1/2 dp 3in dp back no cat???

how big of injectors should i go

Don't do injectors yet. What boost are you running? Whats your spark plug gap, how old are your wiresand what kind?

Darryl

Fuel cut is actually caused by the MAS seeing too much air. There are some tricks that can help you get around it for a while, but the only real solution is some sort of fuel control.

Also check the stuff that awdnot2 mentioned and make sure there aren't other issues involved.

i have a joe c mbc and i have it set at around 14psi so it isnt too high the wires have been replaced with ngk within the last year as well as the plugs(ngk also), not sure of the gap
what is a good gap to run??
i am also running a k&n if that has any affect on it, with a hacked air can

With the stock ignition I'd run the gap at about .028. I'd use the NGK BPR7ES plugs also.

will that make a huge diff???

Yes the gap can make a hug difference if the gap is too large. Too large of a gap the spark get blown out, miss fires, whatever you want to call it.

Spy, yes fuel pressure would be the first thing to try, but a 255 may be the ultimate fix with stock fuel pressure.

Darryl

alright i will pull out the plugs tonight and see what gapthey have and regap them, or should i just buy new plugs and gap them??

The only thing that makes me think the 190LPH fuel pump is not inadequate is the fact that I was able to run staright 112 octane and take knock entirely out of the picture. (Note this is down from 30-40 counts in 3-4th gears). To me that means the compressed intake charge from the turbo is running hot enough that better detonation inhibiting properties some where before the combustion chamber are required.

Obviously you can add a bigger fuel pump and throw more gas per power stroke, but in my opinion that is too rich of a mixture for speed. Other alternatives are a bigger more efficient turbo, higher octane fuel, large front mount intercooler, propane or water injection, etc. Anti-detonation fixes such as High octane fuel and water injection do slow the combustion burn to deter detonation, but I don't feel that either of these slow acceleration down nearly as much as a fuel mixture that is too rich. An overly rich mixture is always slower regardless if you are cutting down detonation...Nate and I have both seen this. Not to say Phat fuel levels aren't safer, but that wasn't what this discussion was about.

BTW - I was running stock injectors and a non-turbo FPR with my 14b on the fastest runs made at 24psi, but it was with the 112 octane gas.

Your probably seeing knock at 4k because that's where your cylinders are the most full. My torque on the galant peaked out there before the turbo went on.

Haha! Better get used to it man.

Marcus is right. If speed is what you're after, lean is what you need. Burn all the fuel every stroke instead of spitting it out the tailpipe or igniting it in the manifold. As long as you have enough fuel pump to get the fuel to the injectors at the proper pressure you're good. Detonation can come from other sources beside a lean condition.

On the other hand, I have no hands on experience with a 190 pump beside what Marcus and I logged, but going by Darryl's experience with his dropping pressure at high RPM's, I'd say if the 190 isn't a problem now, it may be in the near future. Dropping off fuel pressure at high RPM's is something that could kill an engine pretty quickly, so IMO its better to play it safe. As we all know high RPM's is where the engine is working exponentially harder and the available time for an injector to be open decreases rapidly with the increases in RPM's. If you lose fuel pressure especially on a boosted engine the difference between the manifold pressure and the fuel pressure may become low enough to hurt fuel atomization and/or decrease flow out of the injector which can create a sudden nasty lean condition. This is why I would choose a 255. Fuel pressure and injector duty cycle can always be tuned later with an afpr and a SAFC or MAFT, but you got to make sure the flow is there first.

Idology? The parts listed there were meant as individual options to help prevent detonation created by a boost level over the designed levels. The Non turbo FPR is a cheap and easy way to bump your fuel pressure up about 10psi.

And the EVO's ability to pull away from a modded AWD DSM is amazing to me! Natedogg

Haha! Marcus you're Dan's idol, didn't you know?

If you think that your fuel pump is inadequate, adding more fuel pressure will just make things worse. Fuel pumps supply less and less fuel as the pressure increases.

With a stock FPR(~37psi line off), at 20lbs of boost a 190 can supply about 125lph. If you switch to the N/A regulator(~45psi line off), you're down to about 111lph.

So, the N/A regulator will fix your problem if the 190 can supply enough fuel at 17psi and your injectors are just too small, but its not a good idea if you think the pump isn't good enough.

The stock pump is more like a 165lph pump at the same pressure the 190lph actually flows 190. The 190 is just a slightly better than stock replacement for those that don't feel like buying an AFPR.

Stock narrow-band O2 sensors also tend to read leaner as they get hotter, which is one of the reasons O2 values tend to drop as you go down the track. Wide-band and medium-band sensors have temperature compensation built into them. Medium-band sensor is a term I kind of made up to describe sensors like the Bosch LSM-11, which is in between a narrow-band and wide-band O2 sensor in terms of range of accuracy and cost. The added bonus of an LSM-11 is that its output is still compatible with ECU's expecting a narrow-band sensor.

I would have to agree with this from my experiences. The larger than stock fuel pump was installed to push more fuel through the injectors during their open time to make up for the injectors small size. This is the same reason to use the N/A FPR. Increased preasure means more fuel in the same time period....as long as the fuel pump is adequate.

This route also has the benefit of close-to-normal idle without fuel control. Where you normally need an AFC or MAFT of some sort to make the engine idle correctly with larger than stock injectors.

idEology

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

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

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!!

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

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.