So last night I got to thinking about my a/f maps and it dawned on me that my high octane a/f map (little to no knock detected) was richer than my low octane a/f map ( 3-5 counts of knock or higher). I richened up my low octane map and so it'll be helpful if I have issues with knock.

After applying the new map I decided to do a 1/4 mile run, the car felt good and didn't have much knock <5.

Today I decided to get started on the Walbro 255lph fuel pump install. I started by removing the back seat which is held in by two clips near the front on each side. I then removed the fuel pump door which is hidden under the back seat. There's 4 phillips head screws for the door. After that I disconnected the power clip from the top of the fuel pump assembly. Then I tucked in some paper towels around the fuel hoses. Now that the pump no longer had power I started the car and let it die to relieve fuel pressure in the system so that it didn't spray everywhere. I disconnected the pressure hose and return hose and moved them out of the way. There's several 8mm nuts which hold a metal ring around the top of the fuel pump assembly. Once I removed those I slid the ring out of the way and was able to wiggle the fuel pump assembly up and out of the fuel tank. Using a flat head screwdriver I pulled back 3 clips that hold the bottom of the fuel pump cover on. With that out of the way I wiggled the fuel pump down. The only thing holding it up in there was the o-ring which stayed up top. I removed the "hat" that goes just beneath the o-ring from the old pump and slid it on the new pump. I went ahead and used a new filter on the walbro pump and used the rubber seat from the old pump. I slid the new pump up into the assembly making sure there was a good seal with the o-ring and reconnected the power connector. Now it was just a matter of putting it all back together and back into the tank. Of course the initial startup was slow while it built up fuel pressure.

Idle was good and throttle response was crisp and I didn't see or smell any leaks so I buttoned up the fuel door cover and seat.

I started up evoscan and kept an eye on knock nb02 and a/f trims - low, mid and high. Prior to the fuel pump install the trims were 100, 83 and 105 respectively and now they are 100, 75 and 105. Clearly it's very rich in the mid range. I'm no too up on the EVO's ECU yet but I imagine it's close to maxing out the stock ECU ability to keep it from being too rich there. I'll probably go into the a/f map and pull out some fuel to get that trim closer to 100. I did a few WOT pulls and it's clearly a little richer. The NB02 never dipped below .94v whereas before it was more like .90v. I have a WB02 sensor on the way for LM-1 setup on the way so I'll get that tune dialed in to~ 11.0:1 for starters.

Overall this a easy install, I'd rate it a 2 out of 10. I probably spent an hour on it taking my time.

Next I'll install the 780cc injectors.


here are some pics of the pump install:

 

Cool thread. Please keep us updated.

 

Glad to see you on here. I'm looking at the same turbo.

Now, bring that thing to the autox March 3rd.

 

I'm seriously thinking about it... I've never done an autox and hate to wear out my street tires but I suppose I could putt around to get a feel for it

Is the next one at MMP or Greyhound?

 

I need to find out a few things:

1) what rpm/airflow/load constitutes MID Fuel Trim so I can tweak that area.
2) what's required to remove the stock 02 housing. I thought I read somewhere that a control arm had to be moved

 

what software and ecu are you using... looks pretty nice, im coming from an srt-4 and we dont have anything like that so I had to get an aem ems but this stuff your using looks neat

 

I hear ya, I have a 91 Dodge Stealth R/T TT and we cannot do this either which is why I use the Greddy E-manage for it to piggy back off of the stock ecu.

for my evo I'm using the stock ecu and a program called ECUflash to change the stock a/f, timing maps etc.. It requires a purchase of a cable that plugs into the diagnostic port. I also bought evoscan which is some nice logging software but there is a free solution out there called Mitsulogger that works just as well but it doesn't have gauges for viewing it in real time.

 

MMP-we'll be using the NASCAR parking lot, not the road course. Should be a user-friendly (and tire friendly) first autox.

 

cool, I'll plan on making it

 

Just to give you an idea how much richer the car is running with the Walbro installed, I was able to add 5* more timing without getting any more knock.

Prior to the fuel pump I was seeing ~ 248awhp on the g-tech and now it's ~ 236 after adding the timing. I'm done tuning it for now though, the injectors, exhaust and wb02 parts should be in anytime so there's no point in getting **** about the tune when it's going to change drastically very soon.

 

I found a handy utility that reads my saved log files and gives me a trace map to show what cells were hit and I can set a knock threshold. This will greatly speed up tuning.



here's the thread on it: https://www.evolutionm.net/forums/sh...59#post4008659

 

I've been planning on going with the HKS 272 cams but after some reasearch I've decided to go a bit larger and use the HKS 280's for a little better flow on the big end of the RPM range.

The vacuum will be significantly lower at idle and of course the brakes need vacuum when you come to a stop which can cause the engine to stall with larger cams. I think I can overcome that with a little more fuel, timing and rpm at idle to minimize the occasional stall at a stop light.

I have a set of HKS 280's on the way

 

Interesting thread. Thanks for sharing.

 

you're welcome, it's always good to hear about people following my progress. I'll keep this going.

 

The 3" Buschur Racing turbo back exhaust came in, I'll get some pics up tonight, that bullet muffler is massive inside. Also the 780cc injectors arrived. The HKS 280 cams are in town and I'll be picking them up at Fedex tomorrow.

I plan on putting the 02 housing and TBE on this weekend and the rest as I have time.

I'm not sure it's necessary to change the injectors just yet. I might be able to wait until the cams are in.