Well went down to the new local AWD dyno to final get some baselines of where my car sits. First couple of dyno runs were with the following mods:

Turbonetics boost Controller (set @ 1.5/bar or roughly 21 psi)
Bucsher Racing Intake
Walboro Fuel Pump
Megan Racing 3 in down pipe to custom 3 in to an Apexi N1 with not Cat.

Well managed to get a whooping 234.69 hp and 248.32 but if you look at my dyno even running such higher boost with the fuel pump I still can't keep the A/f at a higher number then below 10


Didn't like those numbers so we decided to change out the walboro fuel pump and throw the stock one in. Well fuel was much better at around 11.6 A/F and managed to gvet 254.97 hp and 243.33.

So I guess I was pushing way to much fuel for the car not to like it. I don't know if I should throw the walboro back in and bump the boost up to about 24 or 25 psi though I don't know what the efficiency of the stock turbo is and what the max boost that it can hold would be. But I figured I would at least post up the dyno pics to show everyone what the diffeerence of the 2 fuel pumps and show the stock pump isn't really to bad for basic BPU's. Over all though not to disappointed and still happy with the car so happy modding everyone.

 

Thanx for the info... Finally someone proved that the stock pump is efficient enough... So many bad rumors about EVO's running lean... I still have the stock pump with 272's and boosted up... 12.1 AFR.... Perfect for me... Car is flying!!

 

I've always run the stock pump.. I think the issue really is the headroom for tuning with stock injectors.. When you start going with larger injectors, I think once you go over 620cc the stock pump may not provide enough volume..

Keep in mind, most tuners have never argued that the stock pump is ok, I think the argument was under sustained load, the stock pump was producing output problems which led to the tuners running the injector duty cycle higher than what would be needed to get that AFR.. In turn, when you upgrade to the Walbro pump, you'd find that in some cases the cars would have to be retuned because you've given yourself the additional headroom.

My personal opinion is its not 100% necessary to upgrade the pump, however its a good idea to upgrade it if you start making modifications over the basic Exhaust upgrade..

The key is tuning.. you don't mention how the car was tuned or if it was retuned for a new pump or whatnot.. But if the car was never tuned, then the additional volume could upset the fuel ratios.. and if the car WAS tuned with the stock pump, then the pump was upgraded, but the car was not retuned, you will CERTAINLY find that you will need to retune.

 

Get your car tuned through Dynoflash or Vishnu to maximize your mods and Walbro


BTW...where in PA did you have this done?

 

it's not a surprise to me at all. a lot of people have installed walbro pumps because they're inexpensive and the general perception is that you "need" one.

what the vast majority of people need is a fuel computer. or a reflash I suppose but you *have* to leave the car alone after they tune and most people don't.

 

It looks to me like the upgraded pump overruns the stock regulator and maybe even the stock return line. I'd like to have seen a fuel pressure reading both before and after the Walbro installation. You shouldn't have to retune for a higher volume fuel pump unless the regulator or return line is overflowed resulting in higher fuel pressures and an increase in the effective output of the stock injector. The fuel regulator, if it's operating correctly, should keep the differential fuel pressure consistant across all operating conditions including injector duty cycle, rpm range and boost levels. If you've got to tune the fuel ratios then the pressure regulation circuit isn't working correctly.

 

Well since I don't have an AFC or anything else I wasdoing the walboro as a precaution plus to run higher then 21 psi but I wanted to get a comparison of the stock vs. walboro pump at 21 psi. The walboro was new with maybe about 200 miles on it. The stock fuel pump had about 23k on it. So we dropped the walboro out, put the stock one in, reset the ECU. Put 50 miles on to recalibrate the ECU and thats the difference. Next is an AFC for me and since I got a set of 750cc injectors instead of the 650cc like I wanted (which by the way don't work very weel if you have the 750's in without something to tune them... just to much fuel) the 750's will just be on hold till I get the turbo upgrade.

 

Where are you at in PA?

 

Near Reading about an hour or so west of Philly. Guy just opened a shop up with an AWD dyno and some other nifty gadest like a laser alignment rack with couter balances and all. He has a ton of money into the shop. Its called Creations by Koz and if your not doing anything next weekend Maple Grove Raceway is having the Nopi show saturday and sunday.

 

What city is the Dyno in?

 

Its likely not fuel pressure regulator overrun, the stock regulator can easily handle the slightly higher volume, its not a higher pressure pump but a higher volume. I realize due to fluid dynamics and all that stuff means that yes, its likely raising fuel pressure slightly, but it isn't overrunning the FPR, its just a bit of additional fuel volume. Fuel pressure does drop off slightly with the stock pump, where it no longer does with the new pump..

 

Reading, PA right off Rt. 422 on Lancaster Ave. Tomorrow will post up the exact location and number for anyone thats around.

 

I belive the only influence a pump can have on delivery to the engine is by altering pressure in the rail becuase:

The only variables in any injector size calculation are pressure and injector flow rating. The only variables in flow calculations are pressure and orrafice size. The total fuel delivery is only dependant on injector size, pulsewidth, and rail pressure.

so how much additional fuel is moving into the rail at X velocity, and the same amount moving through the reg and back to the tank at X velocity is a non issue.

 

That is true but that shows that the injectors are most certainly more efficient then the pump is. Obviously, with the stock fuel pump the pump can't send as mucgh fuel as the injectors are aboe to handle nor anything else so the pump is still the weakest point of the system but it is still very efficient. Oh and a side note, if I can get the dyno sheet comparison we did a 3rd and 4th gear run cause they wanted in 4th and I wanted in 3rd and bet $20 bucks that my 3rd would have more power... well guess what? I won... Produced about 15 more HP to the wheels. Just a side note. Don't know why since 4th is the closets 1:1 ratio but 3rd is my longest gear in the track and thats the gear I'm going to tune by.

 

No offense intended with this statement, but I am going to say it anyway. This is another case of a bad combination.

The fuel pump shouldn't have been added and isn't needed until our Stage 4, I know you don't have our stages but that will give you an idea when you will want to start looking at adding one.

The car does NOT need more fuel until then and the only reason for the pump at that point on the stock turbo is for trying to run really boost levels that can only be run if you have race gas anyway.

The AFC or the flash we have will both add close to another 30 whp with what you have done. You could even tune around the fuel pump you already spent your money on if you had either of these and then it would be there for the time you want to run a bunch of boost.

David Buschur
www.buschurracing.com