I mapped a MY00 tonight which ran about 5% CO (840-850mV) in the midrange on a map that usually runs 8-9% CO (880-890mV) which is where I like it for safety and cooling. I find if you go below this you have to start really retarding the ignition to prevent knock even if the EGTs remain low (they do on my car as lean as I dare to about 7% CO). The MAF and lambda sensors were giving appropriate values, and the fuel injector pulse widths tied in being low for the boost level. It was really lean (not much sensible from the lambda sensor at all) in the 1200-2500 region and needed a lot of richening up and you could feel the torque returning. There was not one area of this map that I actually leaned out compared with the Tek 2. Adding all this fuel with only minor changes to the timing wiped out a whole load of -5 to -6 degrees knock correction on a hot day and the ECU actually started advancing the ignition by +1 degree far more than it was retarding (-0.5 degrees). The owner was previously running a Dawes and I have to say I would be concerned about the long term safety of the setup on his individual car given that the Dawes would have been using more advanced timing as it was using the last known good on the end of the AE802 map, although he arrived with the Dawes removed so never logged it. However, richening up a car is not a very sexy thing to do for a remap in terms of top end power, so the effects were perhaps less on this car than some others, but once the fuelling was right, one is happier to add more boost to run at 17.4 PSI held.

I can only presume that all this was due to the resonator removal. Anyone else logged a car with the resonator removed? Might be quite a good mod to lean things out but could easily go too far with other breathing mods and extra boost in the equation. Perhaps the AE802 is better here as it is rich, but with a Prodrive map or a Tek 2 it might be worth checking out the lambda voltages or using an AFR. However, I think you would lose a shed load of low down torque like people have found with the induction kits.

[Edited by john banks - 6/6/2002 9:28:31 PM]

Not on a MY00 but on MY95 fitting an induction kit lost bottom end torque due to lean mix. Upped the fuel pressure as a band-aid which brought back bottom end torque.

I wonder if there is much variation in fuel supply pressure across different cars ? That could explain some of the odd results ?

Andy

Good point. If I put my present 8-9% CO fuel map on a car with more breathing mods and the original fuel pump I think it would be a disaster.

Andy,

Welcome back m8. How was yer holiday?


John,

When you say resonator, do you mean the airbox, i.e the bit that sits in the wing of the stock set up?

Cheers,

Wrexy.

Excellent thanks Wrexy :) 24 - 28 deg C plus brilliant sunshine every day. Lovely Island Kos, very friendly people :)

Note to self.....GTF out of Scotland :rolleyes:

Yes WREXY. Scotland is nice for charge temperatures though. That is about it.

From Sunday, temps are going to hit 40 they reckon for a week. :eek:

Wrexy.

C'mon John! Organise a holiday over here mate. I need a re map! :D :D :D Andy will tell you how great it was. :D Anywhere you decide to go to, I'd come to meet you. And I may have more customers for you too.

Cheers,

Wrexy.

John

Just to say..........if you need a hand out there ;) You know, with the oily bits :D

ECU Europe has a nice 'ring' to it :)

:D

Thought i'd pop into this one....John is this the blue one you did tonight??

I had a very sick sounding sti 4 in this week.On anything over 1/2 throttle the car was surging badly and lambda voltages were dropping to zero.I hooked up a fuel pressure guage & found the press. was dropping off.Turns out the fuel pump was U/S, luckily no engine damage was done.First time i've changed a faulty Impreza pump...anyone elses failed??

I know we all like to monitor AFR, oil pressure & boost etc. but how many folk have a fuel pressure guage??? worth thinking about....

CC
On the few Imprezas I have tested (UK & import) or fitted FSE regulators to, they are usually 30-35psi @ idle, 50-55psi @ full load.What are you running yours at?? (or is it a trade secret :p)

Dave

Hi Dave

Don't tell anyone ;) but I run my fuel presure at 3.2 bar static. On the std pump this gave me only 3.8 bar at full load/boost regardless of std or FSE regulator. It just couldn't keep up with the required flow and thats only on 380's :eek:

I fitted the bigger pump and now still run 3.2 bar static (up 0.2 on std to overcome the off boost lean spot) but I can now hold 5.0 - 5.5 bar at full load/boost.

Andy

I know that the MY99s were having trouble with fuel pumps in OZ. Maybe the MY98s as well. I was told that they were improved on the MY00.

John,

I've run a stock my99 and PPP'ed my00 both with resonator removed, and never had any of the lean problems on pick-up. Maybe a dodgy pump/regulator on this car?

Richard

Could certainly be fuel pressure related.

The MAF values were a bit low for the boost pressure (I am comparing std turbo cars here) and would be more the sort of level you would expect for a few PSI lower - they seemed quite like WREXY's values for similar boost.

John just for your info/stats.

My car ran OK with the resonator removed, the big problems started with the induction kit.

That said, to each their own, but I refitted the resonator, as I now had a good look at the splash guard on my car, and in heavy rain at full boost, it must suck a ****load of water into the filter/onto the MAF ...

......<crumph-craaark-grind>.....

Oh, that feels better - bitten lips ;)

Have a good weekend
Richard

Thanks for the thread John...... got me worried now!

I presume I should get my fuel pressure checked as a precaution?

Dave B..... can you check it for me?

On the back of this thread, I've just re-fitted my Resonator. The noise was beginning to 'P' me off anyway....

might just do the same !

and here was me thinking of removing mine to get that nice sound :p

YHM Chris. I was very happy with your car's fuelling after the map and it was consistent across the range, but we can log it again. I don't have a fuel pressure gauge so maybe check with Dave Brown.

I think it is your MAF reading low though (possibly because of the res removal) - the voltages off it were about 0.1V lower than expected for the boost and the injector pulse widths were appropriate for the MAF voltage, so the lambdas were low. Similar characteristics to WREXY's car. Let's log it again, and we can also make sure it isn't getting leaner over time - a failing MAF could conceivably do this. Sadly the sensors on these cars are not accurate enough in all situations to be able to believe one of them, and when you get odd readings you have to work out which one is lying to you by looking at a few of them, or using external sensors like EGT or exhaust gas analysers.

If for example your MAF voltage seemed appropriate for your boost level, then the injector pulse widths would be as well. A lean reading on the lambda would then make you suspect a hot lambda sensor or a fuelling problem - eg fuel pressure poor.

SCOSaltire your MAF has been dodgy already I would leave the poor thing alone.

Richard, I meant it ran OK fuel wise.

Minues the 2 times when it ran 1%CO on full boost in the heavy rain in Germany at 200 km/h...

Have a good weekend :)

Chris

Pop in & see me, only takes a few mins. to check the fuel pressure.A wee check of the MAF for contamination also.

Andy
Now I see why you modded the fuel lines :rolleyes:

Dave

Thanks Dave, will do.

A Few month ago I made a Hole on gasket number 4 car was running to lean.
I was driving 200 KM/H Rainny day
My car had no resonator KN filter and running 1.2 bar evry thing else stock
Do you think it because I hade no resonator I broke the engine?
If John Banks could answer me would be great
Thanks

scobymars,

Could have been, likely even - but there are many other factors to consider; how you are achieving 1.2bar, was it at 1.2bar when it failed, do you still have fuel-cut, are there any sign's of water in the bottom of your airbox, was the K&N recently oiled, was the splashguard fitted correctly, etc.?

I've run without resonator...blah, blah, blah :D

Richard

In answer to your reply - below for reference;

First the hole was in the piston 4
What is the splashguard ?
the KN was brand new bought to days before
To run 1.2 bar I had a bleed in between T and soleinoide and a bleed before the Map that allows me to go to 1.35 bar
Thanks for your answer

Did you remove resonator same time as fitting K&N? Splashguard is the plastic cover you must remove to take out resonator - if it's not refitted correctly it lets water in...lots! Was the K&N pre-oiled, or did you oil it before fitting?

Richard

Impossible to say? Had the MAF sensor failed?