Hello all,

I am after some advice on engine mapping. My car was bought a few months ago, and when I bought it the head gasket had blown. The garage where I bought it paid for the repairs which were done at a Subaru dealership. It had head and block skimmed, new gasket, new clutch, new ACL big end bearing amongst other small details. The previous owner had it remapped (after fitting exhaust, headers, fuel pump etc) Now that it is all fixed, I’ve taken it to get put on the dyno to see how the car is running. Essentially I am happy with the car’s performance and I’m not really interested in up-rating it anymore. I just want to make certain it doesn’t try and blow a gasket again, in the near future.
When it was on the dyno, the mapper I used said the map was 99% spot on, but he thought it was running lean by approx 4%. He said if he owned the car, he would have this put right asap. Unfortunately, he is not prepared to simply adjust this value in the map, even though it’s possible. Rather he would want to charge to have the whole thing re-mapped again. TBH I could do without that cost at the moment. The car is not suffering from early det (althought its close apparently). I want to know what people think of running lean by about 4% - is it something to be majorly worried about, or something that isn’t a massive issue.

CAR is 2.5 2006 WRX STI Type Uk
Running at 325BHP
chocolate pistons replaced with Forged Cosworth pistons if that makes a difference to opinion on lean running.

 

The parts used by the Subaru Garage will be covered by a warranty. Getting it mapped will invalidate that warranty. But having said that don't tell and hope it's stays in one piece.

If it was mapped previously it should have a license and you should only have a tweak done and that is cheaper. Open source mapping is different and should cost less.

Hope this helps.

 

if its alreday mapped then warrenty fubar already anyway. im surprised they didnt sort the map out when they rebuilt it.

I'd go back to the garage and speak to them about it, if its under warrenty and not running right they need to put it right.

 

the car appears to be running absolutely fine. the only reason i had the dyno done was to check it wasnt over-boosting or running lean, or anything that would harm the longevity of the engine. Car is not under warranty as its 6 years old. The engine rebuilders were a subaru dealership, so they dont have a dyno machine. Essentially they did their job properly. I just want to see what people think of the current map. I.e will running a little lean cause me any major problems?

 

the trooper - thanks for the advice.
The originally mapper was based in the midlands and mapped it for a previous owner. I took it to a local dyno in the north-west. The original mappers are miles away the dyno guys nearest me wont tweak in on open source, only do a full re-map themselves.....

 

mpas are car/engine specific, so if you change the engine it may well affect the map.

if the warrenty is void anyway then get it mapped.

The mapper may well not be able to get access to the map thats on it so may require a full map. It should be about £350 ish cos it will already have a license on it.

 

p.s. lean is very very bad on scoob's. not sure if thats enough to be to dangerous levels, but they like to run with plenty of fuel

 

Can you scan the dyno plots?

 

yeh thats no problem. I'm away with work so cant do them until the weekend as they're at home. At the moment i only have the power/torque graphs. What graph is it called that shows how lean it is running (i.e fuel v air?) I will request these from the dyno man. He has all the info saved there.
Cheers,

 

Yes afr.

Seems strange to specify its 4 % lean rather than in actual fueling

Simon

 

I was thinking the same ( but don't want to say too much , I'll probably be wrong lol)
You don't think he's looked at l/v do you ?

Because to come up with a % figure does seem odd ( too me anyway )

 

4% wouldn't need a remap anyway, the ecu will compensate

 

not on boost it wont..

it might remove a bit of timing if it dets but that wont stop it melting something, just encourage it.

 

You're right mate it would , but some folk like to see a nice round 0

But if he has only looked at the l/v snapshot it's not the whole picture , his dyno run will show , when he posts them

 

is not possible he could be running 4% at the lower end but going into o/l running richer , I know it's then deviating from the progression that may be expected , but is this possible

Where else other than l/v would you get a % reading

 

You will never hit +-0 due to temperature changes

 

it makes no odds if it is lean out the exhaust then the appearance afr is that it is lean.

of course if its rich in closed loop and removes fuel it will then be lean on boost... but thats kind of irrelavant as he isnt tuning it himself

The fact remains its lean on boost.

Simon

 

How do we know it's lean on boost ?

 

Generally speaking when you power run a car, you do it at full throttle

Could try it at light throttle. Heres you graph for 95hp sir.

Simon

 

I'm lost now tbh Simon ,
Where has the guys mapper got the 4% figure
I thought it would be from l/v not a calculated figure from a wot run

Thus why I was saying is 4% may not be relevant at the higher end of the scale or o/l , or like you say A wot run

I was under the understanding l/v is a good indicator to fueling progression but the fueling may not follow on with perfect accuracy

 

lol

 

Glad you find it funny , it's giving me a headache lol

 

Thats why we pay our monies tony so we get power not a headache

 

[QUOTE=addi monster;10876509]Thats why we pay our monies tony so we get power not a headache [/QUOTE

Yeah that's fine addi , are you intent on bringing that into every mapping thread I post in ,has it crossed youre mind i maybe trying to learn or find somthing out

I can soon retort with why do you pay you're mapper to tell you a perfectly useable rom is no good ?

So I suggest we leave it there shall we ?

 

[quote=toneh;10876522] I nearly spat my beer all over my lap top then

You bang on about whatever you want mate

My quote was mearly a truthfull one and not a dig, I also like reading and learning

 

[QUOTE=addi monster;10876538]If you're into telling the truth mate , why don't you get that thread back up you had deleted ?

Dig or not it had no relevance on this thread

 

4% lean is a strange way to present it but also OP is new to this so it could have been told slightly differently.. its 0.4AFR, or it is 0.04lambda leaner.. very easy when being told something that means nothing to you and then come home and post on here slightly wrong wording.. no offense meant to op.

I doubt the dyno operator would have gone into the ecu learn functions and quoted that as its kind of irrelevant as the important fuelling is the measurement out the exhaust..
you can get 99.99999% of the relevant info from a dyno run with detcans on and wideband..
ie. is it detting, is it running correct boost (amount, spool, level), is it producing correct power and torque, is the fueling safe. You can then go digging further with a laptop of course but unlikely tbh on a car that has come in for a power run and you can see that if there is something amiss it will be shown with a power run with det cans on.

Simon

 

[quote=toneh;10876551] Threads get deleted for abuse ect, also if your refering to your little monkey he got exactly what he was asking for (the truth)

Now back on track and sorry to the op

 

Right with you , so you're doubtful that it was a % that the op was given In the first place ( makes more sense )
Same as you say why would you go into learning on a run
I suppose all will become clear if the op posts his sheets

Btw just missed you the other week , when you where at Jason's , gonna start using his rollers , hes only 1min from me and his w/b lol
So there's gonna be no more slagging my dodgy methods lol

 

[QUOTE=addi monster;10876574]Yeah sorry op , let's back track ,,,, sorry get back on track