rolling road 325 tb on 320 (underpowered)

[e30-320i]

just got my car back from the rolling road and found out its making less power than standard it has 325i tb and heat shielded cone filter and a zone chip.the guy that did it reckons its because i have the wrong exhaust on the car mine goes from twin pipes to single at the centre box but he thinks it should be twins right through.does this sound right to you guys.


i,m thinking it may be to do with my chip i bought a used zone chip it was advertised as a 320 chip but when i removed it from the ecu the sticker on the back said alpina 2.7 could this be the problem.?need Ants advice here.

i,m confused now as the car feels alot quicker since i did the tb mod and even better since its been set up on the rollers yet theyre saying its not even hitting standard figures.

has any one timed a standard 320i 0-60 this would give me something to compare

any advice please...

[m-dtech]

This is the norm mate.

Depends on the type of rolling road too.

Most cars are never the claimed bhp.

[jmc330i]

Is that '122HP @ 6040rpm' at the wheels?

I would of said thats pretty good for a 320i if it is.

[e30-320i]

Is that '122HP @ 6040rpm' at the wheels?

I would of said thats pretty good for a 320i if it is.

i think its at the flywheel

[Ant]

Twin from the mainfold changing to single from the middle section back is correct for an 88-90 320i, there are some late cars with small bore twins right through but this will not cost you any real power.

the delivery looks Ok TBH, lets sort the chip for the correct one and see whats what .

[koos]

My 91 320iSE has twin pipes from front to end.

[calder]

does appear a bit low compared to standard for a 320i.
I have a standard 320i engine with no engine mods, chips or bbtb, only change from standard is a cone type airfilter and a Miltek exhaust, puts out 135 bhp at about 5,800 rpm and 129ft/lb torque (at the flywheel).
maybe you have an out of tune problem? hth

[Ant]

those are sound figs for a stock M20 b20, must be in fine fettle Calder

The dyno sheet shows nothing relating to fuelling, we need to see what the wideband picked up during the dyno runs dude, that will shed a lot of light on possible causes

although you're dissapointed dude, A shite set of plugs, dirty airfilter and/or worn dizzy cap and arm could easily cost 10 hp on that engine

[Andy_magic]

I've had 3 320i's all F reg, 2 of them had twin pipes all the way through and the current one has twin from the manifold to the centre box then exits as a single into the backbox then out as one pipe.

I did some 0-60 tests a while ago and think that it worked out as an average of 9.3 seconds.

I can't do any more tests as the car is now a 2.7.

How much did your rolling road session cost you as they are not far from me.

[calder]

Ant, ta very much, kind of your to say so, tbh i've been lucky with a sound engine. Can you explain what "wide-band" means?

E30-320i - i don't know what exhaust you have but changing the exhaust alone to something more free flowing gave me about +5bhp at peak which i know from comparative power runs at the same rolling road. Most people probably wouldn't want the model of exhaust that i have as its running over 99dBA at 4,500rpm and i couldn't live with it if i had to drive it all the time
Check the list of things to check in Ant's post to find something out of tune.
One other item that may be worth looking into is the whole ECU itself as all ECUs are now all over 15 years old. I've not had this problem myself but from talking to several other people there seems to be something in the ECU which deteriorates with age and the symptom is power loss in an otherwise healthy car. I have no idea what the part of the ECU it is that is aging and the only way that i have heard of checking is to swap ECU's on the car in back to back tests.
Maybe someone else knows more?

[Chaos]

Ant, ta very much, kind of your to say so, tbh i've been lucky with a sound engine. Can you explain what "wide-band" means?

educated guess says he means the lambda probe they most likely clamped to the end of ur exhaust

[e30-320i]

thinking about it the exhaust must be right as the rear panei only has a single cut out for the tail pipes i really appreciate all the advice everyone especially ant i'll send the chip asap

the session cost 80 quid but that included a full set up too as you can see it was only 116 bhp on the 1st run and they sqeezed 122 out of it so its worth doing they will also do a power run for Ԛ£40-i think thats 2 runs