KazzEvo8

iTrader: (2)

Hey all - LONG time since I've been active here.

I have an '03 Evo 8 with lots of bolt-ons, White Rabbit Turbo, 880 injectors, OEM ECU w/Dynoflash retuned by Mellon. Purportedly puts out around 395hp to the wheels on 93 octane and runs low 12s easily all day. Ever since Dynoflash touched it way back when (2005?), it's been a ***** to drive with only 2 feet, especially in hot weather. Runs like a raped ape, but terrible to navigate a parking lot with. Mellon tuned it after the last batch of upgrades, including 880 injectors, but couldn't recover any of the driveability. I've loved tearing up autocross in SM with a lot of success, but otherwise the car sits in storage way too much.

1. - It was recommended to me to get newer technology injectors because they could handle idle and such much better than older injectors. I have no idea if that's true. But if it is, I'd like to start there. Can anyone confirm/deny and recommend?

2. - In looking over the tephra mods, etc., that have come out since, I discovered that my ECU is one of the 2003s with the smaller memory available for tuning, etc. Should I even bother to try to re-tune or should I replace the ECU? If so, what do I need to know or keep in mind?

3. - Assuming I figure out 1 and 2, I'd like to add the appropriate mods in the ECU and dial in the best idle & low RPM behavior I can. That doesn't sound like the average dyno-based tuner you go to for an afternoon. Suggestions for getting that done?

There are other small problems, but the above would go a long way to making it easier to drive and probably, unfortunately, sell. Happy to hear suggestions! Thanks!

MinusPrevious

iTrader: (3)

Hey welcome back

Im certainly not the best at ECU mods so hopefully the guys can give you some ideas

Joe

Biggiesacks

Yes newer High-Z injectors work better with the stock ECU then the Low-Z injectors do. Low-Z injectors are meant to be driven by a peak & hold driver that the stock ECU doesn't have. Instead the OEM put a fat resistor in series with with injectors and added a ton of dead time to make up for it. Running High-Z injectors allows you to remove that resister and get better response, especially at very small pulse widths out of the injectors. You will benefit a lot from moving to V7 and no you don't need to worry about your ECU's memory its fine. If you are running a pretty crazy setup and can't dial it in with the MAF then moving to an SD rom and doing the mods necessary for it should allow you to gain that last bit of road manners, but at a cost of climate & altitude having a larger effect on your tune.

Ayoustin

iTrader: (2)

You'll probably get better driveability out of a speed density tune than moving to high Z injectors. I have 1100cc low z injectors and the car idles just fine, all my **** driveabilty is tied to be still being on a MAF tune.

KazzEvo8

iTrader: (2)

Thank you! Good to be back! The place looks the same. LOL

This is all good news. Do you have any suggestions as to which injectors you think I should consider? I'm not sure how large to go, either, in case I - or a future owner - wants to move to ethanol blends. Thoughts?

Thanks and I appreciate your input. I'm not interested in throwing more money into the car (over the crazy amounts I've already thrown at it) for now, as it's likely to be sold soon. If I can get about what I want with injectors and re-tuning, I'll be one happy camper.

Biggiesacks

I don't really have much first hand experience working with High-Z injectors, so hopefully someone who has tuned a variety will chime in. I can tell you that from a budget stand point there is a pretty large increase in cost when you jump over the 1200ishcc size depending on supplier. I think FIC 1200cc's should be good for your power level or a little higher on E-85. You should probably do some of your own research though because every setup and end goal is different.

Pal215

iTrader: (12)

Lots of good advice here.

OP, just remember that a lot of driveability issues like this also have a lot to do with how aggressive your cams are and how good the tuner is at dialing in the injectors, iscv, idle timing, and fuel. I used to have FIC 1050cc injectors when my setup made 429hp and still had a little room left in them. That was on E85. I also found that vacuum leaks can make or break the behavior of your low rpm driving.

SW20Mike

iTrader: (6)

OP, I made a few posts back in the day with the same issues. Car ran like crap when A/C was on and idling, would stall in parking lot or low speed stop and go driving. I lived with it for a few years, but it did suck and I would have to modulate my throttle while driving through parking lots or with my A/C on at times. MAF, aggressive cams, injectors all were pointed out as possible culprits. I've since moved to AZ, and did a bunch of "mods" to go E51 and also make my drivability more bearable. I did add a JDC COP ignition prior to moving, and it helped a bit, but if your coils aren't showing signs of failing it might not be necessary. I just really like the look, and knew I was gonna run more boost with Ethanol. Going speed density has probably been one of the best things I've done for the car. It isn't cheap (Intake $170, 4 BAR MAP sensor $99, VTA bov if you want one $200, Retune anywhere from $300 - $600) but it just made sense to do it while I went flexfuel with a Fitronic kit. I won't say the car drives like a Cadillac now, I'll still stall if I'm going up a steep incline with my A/C on and I'm not paying attention to my throttle application, but its way way better than it was on the MAF setup. Car idles much more smoothly and drives more smoothly. My wife, who doesn't really notice anything I do with my car, noticed my car running better as well. I'm also running low impedance injectors, FIC 1050s, and I went the SD route to make my car drive better. I've been happy so far, plus I just love running E51 now, now I know why everyone hypes it up Best of luck in getting your issues worked out.

Aidanlee1

I would personally use the stock ecu for what you want to achieve from the car. Besides, AEM v1, v2, or infinity won't pass emissions ever!

gqcode

iTrader: (14)

We got the same year Evo and i know exactly what you describing. Switching from Low-Z to high-Z will change how your car is running especially in the low rpm. Once I did that with my tuner (road tune) the car felt so smooth as if I had purchase a new car. But also remember the tune is only has good as your tuner! If you don't plan for more power or E-85 than 1000cc should be fine. As far as the ECU you be OK, there no need to upgrade the ECU unless you plan on doing some really racing but even that the stock ECU can handle it. Aftermarket ECU make it easier to tune and does offer a lot more options but as mention you should be fine with the stock.
Speed Density also help a lot vs the MAF and I would recommend

KazzEvo8

iTrader: (2)

Thanks, everyone! Sorry I've not been here to look in. The car's back in storage after very little driving this summer, unfortunately. I'd like to start turning it around with low-Z injectors (1200s?). I'm still concerned about the ECU being that early-2003, limited memory version, but will give that a try, as well. Then I'll be all over the place here trying to figure out how to get the tuning started. LOL Happy 2020 everyone and thanks! Always welcoming more constructive input!

KazzEvo8

iTrader: (2)

I'm finally back to this, and going to move on some high-Z injectors (FIC 1200s, I think). I was curious about this 'resistor', though. Is it built into the injectors or somewhere inline? If it's somewhere inline, can it be safely removed?

I think I will go w/new injectors and V7 first and then consider speed density if I'm still not thrilled. I'm back on the fence about selling her. I'm sure it will be tougher once I get her rolling properly. LOL

hutch959

iTrader: (18)

its on the firewall.
i think fic (and others) make a resistor bypass plug.

simply unplug the resistor and plug in the bypass plu

DontStopMe

iTrader: (19)

Skip to 2:50

KazzEvo8

iTrader: (2)

That's fantastic guys! Thanks! Now to find some help getting her tuned from the ground up. Or take it somewhere - Chicago or St. Louis since I'm between them both.