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e36 325i - All this blood and sweat for 172 horses =[

9K views 57 replies 9 participants last post by  mistreku 
#1 ·
Just been to dyno my car. The current list of mods is US Spec 3ltr M3 cams, Big bore Throttle Body, Decat, M3 Backbox and a fart valve. On an M50B25

And the dyno shown 172.8 HP :frown The fuel map shown that the car is running wayyyyyy too lean! And it is very very lumpy. Has a massive dip at about 4.8k revs and the max torque is 166 ft/lb.
Rather pittyfull to be honest. Altho the peak was at 6080 rpm
Any suggestions? But the AFR is rediculas. It goes up to 15.2 at 2500rpm and then drops all the way to 13:confused
Will upload the pics of the graphs a bit later.
 
#3 ·
The lamba probe was replaced last summer when i don the conversion. But wont the fact its running to lean mean its getting plenty air and not enough fuel? I will upload both printouts but the fella in the shop said that it could be a number of different things. But what he said since its running that lean it just wont let the timing to advance properly.
 
#7 ·
46cc @ 3bar and 50% duty cycle?
That doesn´t sound right at all.

That´s way to low.

It´s starving for fuel at least that´s a given. but even though you should be seeing more power up top with that AFR up top.
 
#8 ·
Yea, thats what they were tested at. And that was tested with V-power. Thats all I ever run. Seems a lot happier with that petrol, never used octane booster in it as I read and people say that it doesnt seem to do much.
I just thought about trying the 323 injectors from the other car just to see if I see any performance improvement because Im letting my dad use it at the moment and it seems to be pretty poky. And that the 323 injectors are same as 325. Would the US spec M3 cams have anything to do with this or the decat? I noticed on the graph that the peak power has shifted from 5900 rpm aswell.
Or maybe try increasing the fuel pressure?
 
#9 ·
What is the mixture like during cruise?

I´d replace the injectors with the correct ones or marginally larger.
And definitely get it remapped.

And those injectors should not be flowing 45cc@3bar , I´d say the test was wrong as they are supposed to flow alot more.
 
#10 ·
Thats the problem, I got no way of monitoring my fuel mixture at the moment.
I was thinking of putting them 323 injectors on just as a check because that car seems to be running rather well. But also thinking about 328 injectors as they are Bosch aswell. But the question is, would my ECU be able to adapt if I put the 328 injectors on?
 
#12 ·
Just had a look around and I think I may have found the problem. I was a bit stupid and didnt realise. Just checked what the flow rate of my injectors is meant to be on here http://www.injectorcleaning.co.uk/flow.htm and its meant to be 160cc not 49cc:frown:banghead so I think I may need new injectors.
What do you think? But when it sayed on the injector print out, it said 50% duty. What does that actually mean?
 
#27 ·
I use to have a 323i and the engine is the same as the 325i but the difference is the manifold and the exaust. It does have 170 bhp. And i had it up to 145 mph in the rain. It goes like a train at least my one did.
 
#22 ·
But wont the fact its running to lean mean its getting plenty air and not enough fuel?
Which could be caused by
I would also check all air pipes for splits/leaks.

I would advise a diagnostic scan to see if there are any fault codes recorded on the ECU.
A scan will flag an injector fault;) Even my Peake Research tool flags this, I know because I have seen it:thumbsup

Once you have checked for split/leaking or even disconnected pipes have a diagnostic scan performed on the vehicle.


Just a heads up;) When I put the M3 engine from my Coupe into my Touring I accidently left off an earth strap which caused a number of fault codes to be thrown up. Onceit was reconnected and the old codes erased it was fine.

Don't go replacing this that and the other without first checking the simple and common causes:thumbsup
 
#23 ·
Thanks for the heads up mate. Will have to wait till end of next week when I got some free time now as I got 2 uni exams to get ready for next week:frown

But will definatly get a diagnostic scan done. Just a bit gutted my mate cant do it in his garage as they dont have OBD1 tools.

Just not liking how my car is running that lean at the moment. Gona take it easy for the time being.

Will keep posted with my progress. But definatly not happy with the fact that an e36 323 can keep up with me :jaw-dropping
 
#26 ·
GStuning, Yea, I checked the part numbersand done a bit of cross referencing and the 323 has same injectors as my 325

And RJB328i, yea I am thinking about it, I thought about the fact that Im running that Big Bore Throttle Body aswell, that would contribute to the lean mixture so the 328 injectors are on my list, just trying to remember what scrappy I seen a 328:hihi

Just another question, how much am I looking at for a new Lambda sensor? I think that could be dodgy but really need to plug it into a Diagnostic machine and fined out.
 
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