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Just working on tuning a supercharged BMW330i. The car came with a supercharger already fitted but with terrible performance - around 220 bhp (alomst the same as sotckk) with the Supercharger.

With the Unichip fitted and a basic tune, achieved 307 bhp. The car owner says "enough!".

Is this JD's old car ?

Yes, it is the same car !

Can we have some pictures ?. Ho a log also would be fine .

Here's a picture of the layout. I will post the dyno charts soon.

Below is the dyno chart of the car after the basic tune. The power is 306.6 bhp at 6000 rpm. There is some more headroom for pushing the power to about 325 bhp.

However, since the car is going to be a regular street use car, it has been brought down to about 300 bhp.

As you can see from the above pic, the MAF sensor has been done away with to reduce restriction on the intake. The MAF signal is simulated by the Unichip using the newly installed MAP sensor's output. The car now runs without the EML light coming on.

Does the removal of the MAF affect fuel efficiency?

Difficult to say. The fact is we are now allowing more air to go in and are correspondingly increasing the amount of fuel. The car is also now putting out much more power than before.

Generally since forced induction engines are run richer than NA engines, too many parameters have changed to make an accurate comparison of the figures before and after.

The tuning has been completed just yesterday. Will certainly follow up with the car owner and find out if he notices any improvement in consumption, although I doubt he scrupulously checks the consumption.

How about the Torque curve on the same?

I am sure that you have made ground there as well.

Cheers!

Can you show us before and after power curves. What ECU/cal was it running before. You cant just unlock 100 bhp by using a unichip!!

Clearly something was mechanically wrong with the car which it appears you have fixed.

As I mentioned in the opening post of this thread, the car had already come with the supercharger installed, but had not done the necessary changes to other things like fuelling. The supercharger kit came with a primitive fuelling control device which was fitted in series with the MAF signal. This was not doing the job, with the result that the car was running super lean. The ecu was also probably backing off the timing.

The ecu was and is still running on the stock ecu. It now has the Unichip installed. The fuelling control device which came with the supercharger kit has been removed.

Posting the 'before' and 'final' after readings below. We did not get 100 extra bhp - we got around 50 odd bhp.

Stock is around 220 odd bhp; when the car came to us it was having about 250 odd. We ended with about 302 bhp.

The primary problem was that the supercharger installation was not complete/proper as no meaningful tuning seemed to have been done.

I agree that there is no way any ecu or piggyback will get 100 bhp out of thin air !!

Power before:


Torque before:


Power final:


Torque final:

Quite possible. If the car came to the OP in a badly tuned state, just fixing the fuelling and ignition would extract most of the power that was being hidden by the bad tune.

Can you post a dyno graph without so much smoothing?

1. Exactly !! All we did was to match the fuelling and the timing for the air that was being supplied by the supercharger !

2. This dyno is primarily a loadng type dyno which can also run in the inertial mode. The reporting/printing/database module of the software is common to both the modes. and works by interpolating between finite points (we can select the interval down to 500 rpm).

Therefore, although the screen display of the inertia mode shows the jagged graph with no smoothing, the reporting/database module takes the inputs only for the fixed points and creates the graph - hence the smoothing in the graphs. Thus, this is the format of the display.

Therefore, during the inertial run, we can see the graph with no smoothing - but can't print it !

OK, if you say so. But its baffling why someone would take the trouble of doing a S/C kit on a 330i without the right fuelling cal. If I'm not mistaken the car has been tracked at MMST by KD.

Are the stock injectors capable of handling the fuelling requirements?

Most of the bolt-ons sold today are still sold with the crappiest of fuel management components which are just mechanical devices aimed to bypass the MAP/MAF sensors, while the increased fuelling requirements are taken care of by raising the base fuel pressure and the O2 sensor voltages taken care of by other means. At the end of the day, most people, including tuners, just bolt on the components that they've got in the kit and send the car away.