I was tuning a friend's 03 Evo VIII this evening and when we turned the boost up to nominal 21psi spiking to 22 or so it started knocking a steady count of 8 from 6K to redline. I turned the boost down to peak 21 psi and the knock went away completely. I reviewed the logs and noticed two things, the knock started exactly when the airflow got to 1603 and then I figured it's a fuel delivery issue so I checked IDC and when it got to 83% IDC was when the knock started. Do you guys think a fuel pump is the issue or something else? Also at 21 psi peak the IDC got to 83% at redline but there was no knock but the airflow never got to 1603 (max). The car had rock solid 11.1 AFR but was a bit richer at the lower boost setting. We are going to work on the tune some tommorow as well.

Oh yea, it's running 9417008, I havent had a chance yet to see what revision that map is or if I should update it with a newer revision.

Also, what kind of power (Dataloglab) should a 03 Evo VIII be making with these mods (ball park)?

Current mods on the car
Ebay Turboback (catless)
K&N drop in
AEM Truboost
AEM Uego

 

Did you try backing off the timing in the knock areas?

MB

 

if the AFR is low 11 and you're knocking at 21psi then it's time to tweak the timing.

p.s. I see ~ 275tq @ 4391rpm and 314hp @7797

 

I had just started tuning it - getting a baseline and getting the boost to a level where we want to tune it, getting his WB setup for logging etc. The timing map was stock when I saw this behaivior. Since this is the first VIII I've ever messed with I wanted to check to see if it was just something that needed to be upgraded right away. I know alot of VIII people highly recommend a fuel pump and I just wanted to know if that's what I was seeing with the brick wall of 8 knock counts at 6500 - redline. I have a IX and am still running on the stock pump although I'm going to upgrade mine soon as well. I'll see if pulling 3 degree's of timing resolves ore lessens the knock. Thanks for the response.

 

I would pull 1 degree at a time, 8 counts isn't that much and you don't want to pull more timing than you have to or you'll rob it of power.

The stock pump is typically adequate until you do cams, turbos etc.. installing an intake and exhaust is probably going to be fine, but do some logging to find out for sure or go ahead and install a fuel pump if you're concerned or plan on doing more mods later.

 

I get random <10 counts of knock sometimes, if it was a steady 8 I may have some concern. I also have a 03 VIII. The worst knock i had was a 23 with a stock map with the ac on going up a hill. weird. and the funny thing is i couldnt re-create it. Ive seen different arguments about knock, some say 2-3 is ok, some say <10 is just noise. If you can post a pic of the evoscan log. it helps.

 

The stock fuel pump can be insufficient after 5500rpms. In my tenure logging and tuning Evo's over the years I always had the attitude that I won't believe anything I read until I see it. While tuning in New York, I ran across a 2005 VIII which would not flow enough fuel no matter how the fuel was mapped after 5500rpms. So this does actually happen and you should always upgrade your fuel pump.

Another local here who I tuned to low 12's on pump with a 2005 had the same symptoms and once he installed the pump the car got slower. We went and logged it once again and the additional flow and pressure threw the AFR's into the low 10's.

Now your issue could be a number of things including insufficient fueling, however the point is to prove otherwise the claims that your stock VIII pump is sufficient. Neither of these two examples had cams, etc.

 

How do you claim there maybe insufficient fueling, but the OP says the AFR is 11.1 ?

MB

 

Depending on the mapping it should richen at higher load. He states it richens at lower load so unless they screwed up the mapping, it does not sound right.

I did state that it could be a number of things and not to rule out insufficient fueling based on someone's opinion that stock fuel pumps are sufficient as up until you have cams.

 

Hey guys, found the trouble - it was a transition in the stock timing map but I think that IDC's of 90% are too high and that the owner should get a pump. Also after logging the car w/wb02 the fuel map needed a little work too. Anyhow this VIII made 265 / 247 on DLL uncorrected except for weight (baseline was around 220/215),

 

Mr. Evo IX, if you get to the point where you added all the fuel you can in the map and the car still isn't getting richer then sure, you've got a fuel supply issue but that still doesn't necessarily mean it's the pump, it can be a dirty fuel filter, kinked line etc... of course adding a fuel pump is never a bad idea unless someone doesn't know how to tune for it. 90% IDC sounds high but many people run up to 120% before having any REAL issue.

you can attack a problem many ways, one is to throw a bunch of money and parts at it or you can troubleshoot first and make a wiser decision based on the gained knowledge.

 

Although i have seen many EVO's that needed a fuel pump upgrade with just a full 3in exhaust, intake and boost around 22 psi......it really depends on power output, not boost or mods. Anything over about 300whp and it's time to ditch the stock unit. You may or may not NEED one right away, but with added boost and or more mods down the road, it's a sure bet you will. It's also a good safety mod even if you don't really need it yet.

My particular EVO needed a walbro 255 as soon as i put a 3.5in full turboback exhaust on. With the increase in flow out of the engine and the addition of a drop in filter and boost @ 21psi, my IDC's where over 100% @ 6800rpms.


CJ

 

Yeah every car is going to be different, but I have three local cars here on stock pumps with TBE, MBC, Intakes and they are fine, another has a FMIC and 02 housing on top of that and he's fine too. I'm just not a big fan of throwing parts and money at a car until it's necessary and frankly I trust the reliability of the stock fuel pump over an 80.00 walbro aka whinebro or botched install that some people do. The best advice is to log your car and find out if you need it or not and in this case he didn't "The car had rock solid 11.1 AFR"

 

Please read: https://www.evolutionm.net/forums/announcement.php?f=2

The comments by TTP were not a slam. He was advising a member on possible false information he was receiving about stock fuel pumps. Thanks.

 

In time and tenure, one ends up with enough experiences to realize that if it can happen to some cars, all cars should have the pumps replaced to deter the chances of catastrophic engine failure on a cold day with insufficient flow.

Three cars in not a sufficient number of cases to make a broad determination that a fuel pump upgrade is not needed until you have cams. I would hate to be #4 that threw a rod over that logic.