Hi,
just wanting some opinions on whether some post tune mods would affect my tune ie a/f ratio.

I had a feeling it was out a bit and it seems my car is now running dangerously lean, especially very early on in the rpm range.
It goes from 15:1 or more down to 13:1 and back up to 14.5:1 also different dyno different days but down about 20hpatw

Since the initial tune i have had a 2.5" hi flow cat (originally 2") fitted and changed my intake from stock airbox + panel + ribbed tubing cai to
3" bends down to front bar and pod. The maf was still left in place on the 1st tune but i removed the unnecessary restriction.

So just want to know how much these could affect the a/f ratio as tuner at the dyno place mentioned to check things like exhaust etc before i fork out some dosh for a retune.

Thanks

well i am thinking it definitatley changed it....looking at mine it was pretty wobbly as well and also down about 10hp on original tune after i hi-flowed my throttle body. I found mine very lean at the start got a bit rich and leaned out again. So i reckon a tune would release a few ponys. Disciple had the most consistant a/f line out of all of them and I dont think he has done anything since his tune.

Just don't anyone mention me :redface:

Ive done nothing bar muffler and pod (not yet relocated) and it was terrible, I never knew the car was THAT out of whack! Anyone got any idea's why it ran so rich? a/f or o2 sensor(s) half dead perhaps?

Did you guys filming at the front hear any knocking/pinging? my mixture was up to the 13's so it was wasting a LOAD of fuel.

Old fart mentioned fuel because I've been on 95 octane e10 pretty much since I've had the car (year or so) but I can't imagine that would effect it THAT much. This has me rather worried, I don't want to fork out for a AFC and tune :/. Oh and sorry about all your noses.

cars can run pretty lean from factory. Very similar to other magnas there today. Dont think its out of the ordinary, you just have to spend money to fix it. Before i had my emanage it went from around 12.5 down to 11.2....too rich. now it should sit around 12.7-12.9 all the way thru.

Your a/f is actually lower than mine, why was I belching fuel when you arn't? (your further from stoich than i am)

Your a/f is actually lower than mine, why was I belching fuel when you arn't? (your further from stoich than i am)

Nick I think you got it around the wrong way, the higher the reading the leaner your car is running - the lower the reading (mine for example, the richer your car is running.)

Nick I think you got it around the wrong way, the higher the reading the leaner your car is running - the lower the reading (mine for example, the richer your car is running.)

Yeah i said that.. my lowest reading was around the 12.9 (or so?, richer than stoich) and my car was belching then, yet his is 12.6-12.9 and doesn't blow any fuel.. how can I be as rich or MORE stoich (said best a/f-ratio) than him and blow fuel when he doesn't?

My richest my car hit would be at 12.7 and most lean wasn't actually lean at all at 14.5ish..

I'm just confused, does the fact that he has a 3.5L and I have a 3L make the difference?

Re Mixtures. 14.6 or 14.7 is for normal cruise. Under load best settings are around 12.7-12.8ish anything over the 12.8's your start running lean anything below the 12's you will run rich. Some vehicles can tolerate the 13's.
LPG cruise mixtures are apx 15.5.
Usually if you get in the 10's under load you should see black smoke comming out of your rear tail pipe.
One thing i noticed today here in Melb at the dyno day the mitsu's are tuned pretty good till they get up to the higher rev range most were running in the 11's to 10.1. (stock or very near stock). If you could lean them out to the mid 12's you should make some power at the top end.

Regards

Well i was running lean as a mofo then yet belching fuel. What i want to know is, why the hell was i throwing so much smoke yet running lean?!

Well i was running lean as a mofo then yet belching fuel. What i want to know is, why the hell was i throwing so much smoke yet running lean?!

i can't help you with that mate, why was i running so much richer than you.. i was below 10
yet not a puff of smoke out of the ralliart.... the guys there told me for my car my air fuel ration should be consistent between 12.5 - 13 and if i can work on gettin it up to there then i whould be makin high 190,s and after looking at the other figures, maybe even 200.

i can't help you with that mate, why was i running so much richer than you.. i was below 10
yet not a puff of smoke out of the ralliart.... the guys there told me for my car my air fuel ration should be consistent between 12.5 - 13 and if i can work on gettin it up to there then i whould be makin high 190,s and after looking at the other figures, maybe even 200.
Don't get too excited. I have extractors + zorst + tune and my AF starts at 13.5 and finishes top end at 12.5 and my car made 190hpatw. It made more on a different dyno couple months ago, and was making consistant 193-195hpatw runs, but with only 2 runs yesterday 190 was all I managed.

sorry to highjack but whats the rough cost of a tune? as mine needs one.
cheers

If you have a tunable ECU probably an hour or so on a dyno for a nip-tuck. Maybe less. Ring around to some local performance shops and ask if they have dynos and the ability to tune your ecu.

Don't get too excited. I have extractors + zorst + tune and my AF starts at 13.5 and finishes top end at 12.5 and my car made 190hpatw. It made more on a different dyno couple months ago, and was making consistant 193-195hpatw runs, but with only 2 runs yesterday 190 was all I managed.

yeah we have bout the same mods less the ecu, so I wouldnt be expecting much different to you if i can manage to get the tune right... atleast after yesterday I know why its goin through the fuel..

yeah we have bout the same mods less the ecu, so I wouldnt be expecting much different to you if i can manage to get the tune right... atleast after yesterday I know why its goin through the fuel..
Ah, I thought yours was stock man, my bad. Yeah, well in that case then you should make same as me theoretically - 190-200hpatw. Chip+tune isn't cheap tho, I paid $1700 I think for the haltech interceptor + tune + plugs, leads & fuel filter. Mine was done at Bob Romano by Chris if you're interested.

Ah, I thought yours was stock man, my bad. Yeah, well in that case then you should make same as me theoretically - 190-200hpatw. Chip+tune isn't cheap tho, I paid $1700 I think for the haltech interceptor + tune + plugs, leads & fuel filter. Mine was done at Bob Romano by Chris if you're interested.

did you not hear it??? but yeah I know tune isnt cheap at all.. and definitly not on the top of my list of things to do atm. car is still running ridiculously rich in my opinion, so checkin out a few other reasons for this. O2 sensor etc... might even be my fuel pressure regulator a bit out of wack. who knows really just wait and see. but was definitly good to find out that it wasn't running right.

did you not hear it??? but yeah I know tune isnt cheap at all.. and definitly not on the top of my list of things to do atm. car is still running ridiculously rich in my opinion, so checkin out a few other reasons for this. O2 sensor etc... might even be my fuel pressure regulator a bit out of wack. who knows really just wait and see. but was definitly good to find out that it wasn't running right.


You have a rising rate one dont you? Take it off and put the stock one back on, see if i makes a difference. Lol is this off the topic though

AJ, exhaust will make a difference to the tune but I cant see it being that much out of whack, phone up the guys who tuned it and have a chat about it.

i had an almost identical a/f reading before i put in emanage. i doubt there is any problems as it is just a factory setting...won't hurt to check tho for peace of mind.

A mod should not effect the tune. It will make the ECU read from a different load point, which should have been tuned for in the first place, but may not have been.

well its going back to the tuner on thursday, so will find out then

What ECU

A mod should not effect the tune. It will make the ECU read from a different load point, which should have been tuned for in the first place, but may not have been.
But if you get an exhaust system put on, the factory ECU will only adjust for the extra flow so much... Plus if you've already had a tune done with an ECU (like me) and then changed your air intake (like I did), that would mess with A/F ratios a bit, right?

But if you get an exhaust system put on, the factory ECU will only adjust for the extra flow so much... Plus if you've already had a tune done with an ECU (like me) and then changed your air intake (like I did), that would mess with A/F ratios a bit, right?

What TC is saying is correct. If the car was tuned correctly in the first place the ECU (whether piggyback or standalone) should be able to register the difference in airflow caused by mods such as an exhaust or modified intake, and compensate accordingly.

What TC is saying is correct. If the car was tuned correctly in the first place the ECU (whether piggyback or standalone) should be able to register the difference in airflow caused by mods such as an exhaust or modified intake, and compensate accordingly.
Ahhh k. The dyno print out I got from when I had my car tuned doesn't have an A/F graph on it, neither does the dyno run from last years dyno day so I can't compare. Interestingly tho, my car made peak power almost 600rpm further in the rev range when it was initially tuned compared to the dyno day run.

what would constitute it not being tuned correctly in the first place...like what haven't they done?

Would a FPR be able to richen me up to be safe or would a FPR not be able to be tuned that much?