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Discussion Starter · #1 · (Edited)
I went to Bexley Motorworks to pick up a car for a friend and noticed the Dyno bay was empty. So decided to do a dyno. I was realy nervous at first as I knew I would be annoyed if it gave anything less than 290 bhp.

Anyway, temperature was 25 degrees.

1st Run: 297 bhp - Lambda showed over fueling

2nd Run: exactly 300.00 BHP - still over fuelling accross the rev range especially top end

Anyway, Im extremely happy that my M5 is making 300 bhp still and once the over fuelling issue is sorted the power will defintaley get very close to the stock 315 bhp.

I also took the rear wheel BHP which was just over 255bhp.

I will post up the graph as soon as I find a scanner..

:1:
 

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Here's mine from waaaaaayyyyyyy back in 2000. Green is standard, before chip was 'reset' (red) to give me back my missing ponies.



 

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Cyrus said:
I went to Bexley Motorworks to pick up a car for a friend and noticed the Dyno bay was empty. So decided to do a dyno. I was realy nervous at first as I knew I would be annoyed if it gave anything less than 290 bhp.

Anyway, temperature was 25 degrees.

1st Run: 297 bhp - Lambda showed over fueling

2nd Run: exactly 300.00 BHP - still over fuelling accross the rev range especially top end

Anyway, Im extremely happy that my M5 is making 300 bhp still and once the over fuelling issue is sorted the power will defintaley get very close to the stock 315 bhp.
------------------------

Hi Cyrus

How will they fix the overfuelling, will you put on an adjustable fuel pressure regulator?

rgds
J
 

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I am down on Torque on my M. I think mine was 275 and my bhp was 331.
 

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Jahangeer said:
Cyrus said:
I went to Bexley Motorworks to pick up a car for a friend and noticed the Dyno bay was empty. So decided to do a dyno. I was realy nervous at first as I knew I would be annoyed if it gave anything less than 290 bhp.

Anyway, temperature was 25 degrees.

1st Run: 297 bhp - Lambda showed over fueling

2nd Run: exactly 300.00 BHP - still over fuelling accross the rev range especially top end

Anyway, Im extremely happy that my M5 is making 300 bhp still and once the over fuelling issue is sorted the power will defintaley get very close to the stock 315 bhp.
------------------------

Hi Cyrus

How will they fix the overfuelling, will you put on an adjustable fuel pressure regulator?

rgds
J
 

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farrell said:
Its quite common for these cars to overfuel on rolling roads.
Its a harsh environment for taking multiple power runs.
The combination of static heat soaked engine compartment with no positve air flow through the cooling pack & lack of pressuried air to the intake means that the DME will take rising intake air temp, oil & water temps to run a fuelling strategy that will prevent leaning A/F ratios.

Once wide open throttle percentages as dictated by mapping strategies within the DME are achieved,(not where the driver physically perceives wide open throttle at or nr the full travel of the gas pedal)
the 3 way closed loop fuelling goes open loop to fuel for performance rather then for best emissions eficiency.

They have no knock sensor in the head to monitor combustion chamber temp & therefore, any impending detonation problems are dealt with in this manner.

I doubt that there is a problem with the fuel pressure regulator.

Regards
Farrell
 

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Farrell

Ok so on the dyno the DME adjusts to overfuel, but on the highway - the difference in what the DME does is not the same, is it?

If so will Cyrus's car run ok - off the dyno on the highway where it is being cooled?

So is it an in built function in the original DME to protect the engine at higher revs - when there may be a chance of running lean - which from experience I know to be disastrous!

Am not really technically minded when it comes to this kind of detail, but love to learn this kind of stuff, so please bear with me.

Regards
J
 

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Jahangeer
Your comments are a fair understanding of what may happen.
The fact that you run a vehicle on a rolling road does not SIMULATE all the "on the road conditions".
This is something we know & accept.
The fact is that in many cases, you can STIMULATE the vehicle to produce the worst conditions possible for a true power output.

During Wide Open Throttle applications where maintaining a lambda air fuel ratio in not the priority for emission test or low speed part throttle fuelling,
The fuelling strategy will take account of the intake, exhaust, water & oil temps.
Under high temperature conditions, extra fuel is used to cool the combustion chamber by wetting the intake charge & altering ignition spark, attempting to stabilise engine combustion temps.

On the plus side,it looks like Cyrus has good engine performance form his M5 which is good new.

Regards
Farrell
 

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farrell said:
Jahangeer
Your comments are a fair understanding of what may happen.
The fact that you run a vehicle on a rolling road does not SIMULATE all the "on the road conditions".
This is something we know & accept.
The fact is that in many cases, you can STIMULATE the vehicle to produce the worst conditions possible for a true power output.

During Wide Open Throttle applications where maintaining a lambda air fuel ratio in not the priority for emission test or low speed part throttle fuelling,
The fuelling strategy will take account of the intake, exhaust, water & oil temps.
Under high temperature conditions, extra fuel is used to cool the combustion chamber by wetting the intake charge & altering ignition spark, attempting to stabilise engine combustion temps.

On the plus side,it looks like Cyrus has good engine performance form his M5 which is good new.

Regards
Farrell
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got it! that is why at high speeds and revs on the high way - it is advised not to take ones foot of the throttle immediately (in non-emergency situations off course!). Since the engine may have a heat spike? As there is a sudden interruption of cooling fuel supply...

I wonder if this is one of the factors that many "broken" M5's suffered from.

Regards and thanks

J
 

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Discussion Starter · #10 ·
Rolling roads truly are a harsh envirnoment. Bexleys said the power was spot on.

The over feulling was very heavy though. This could be down to a faulty MAF, maybe a sensor out, could be alot of things.

The main point is as farrell has pointed out is that the engine is very healthy.

Set of cams and a remap might well be on the cards seeing as the engine is producing such good power.
 

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Cyrus said:
Rolling roads truly are a harsh envirnoment. Bexleys said the power was spot on.

The over feulling was very heavy though. This could be down to a faulty MAF, maybe a sensor out, could be alot of things.

The main point is as farrell has pointed out is that the engine is very healthy.

Set of cams and a remap might well be on the cards seeing as the engine is producing such good power.
-------------------------

Cyrus

Its a good feeling to come away from a technical test of the engine and get the thumbs up! I know.

RE cams and tuning, do it - you wont regret it, the car is much more responsive lower down, pulls strongly - and with a bigger thump in the back at 4,000rpm. And as you quite rightly said its better to do it to a healthy engine.
regards
J
 

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Discussion Starter · #12 ·
I just realised something.

I didnt put the reccommeded 97 ron fuel in it !!!! I can always feel the difference between the two in this car.

What fuel did I have ??....... Supermarket 95 ron (OK OK...I was running out of fuel and didnt have an option and tesco was closest).

What Cams are there for this car?
 

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Cyrus said:
What Cams are there for this car?
Not many options here.
Schrick & Dinan are the only ones that I am aware of.
The schrick items are reputed to provide greater lift & duration.
This would require possible changes in fuelling to capitalise on the small gains these may provide.

Downside could be a peakier power / torque curve.

Speculation rather than hard fact.

Regards
Farrell
 

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I did not notice a drastic movement in the peakiness of the engine, there just seemed to be more power across the rpm range especially lower down, and I find myself changing gear around 2000revs now.

There is more fuelling needed and that is why I opted for the UNICHIP to help tune the cams and the kats/SS exhaust together, made it alot smoother idle and the rest of the rev range. At 4000rpm, there is a sweet spot followed by a nice shove in the back - that is more noticeable than before.

The Schrick cams cost 16500 Swedish dollars :hihi:
Installation at BMW for cams was 500gbp.
Thats 1200gbp roughly. The UNICHIP cost around 450gbp.

Best money I ever spent on any car. Make sure you get the right valve clearance, its 0,35 inlet and outlet sides. BMW did a phenomenal job on this, and the engine runs beautifully, had an inspection 2 in May and they told me save the valve clearance (and the savings) to next time.

Regards

J
 
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