I thought that I would bring you up to speed on my exploits over the last few weeks.
For a long time I have had an issue with the airflow meter setup on the M5 and the resultant restriction it places on this great engine. I have researched loads of different options from standalone systems to simple remaps. I ruled out the standalone options from Motech, DTA and emerald due to cost, loss of the OBC functionality and the fact that they are a permanent addition to the car. Many people believe that these cars should be left alone in their original glory but I belong in the 'if it improves the car and it can easily be bolted on or off then its a good thing camp!!' Remaps were out due to the afm remaining in place and the lack of knowledge that most 'chip tuning' companies posses when it comes to these old cars. From my perspective the the most important thing was to find a company with a good product, proven track record and the interest to fit it.
After long discussions with Paul from Circuit Motors (a UNICHIP dealer) it was plainly evident that he is a very knowledgeable guy with excellent knowledge of e30 M3's and by association the M5. As a result the car was booked in leaving me a few weeks to check the car over an replace items that could possibly cause issues down the line, namely the distributor cap, rotor arm and temperature sensor. I also got the dial guage out and reset the throttle angles and checked the WOT angle was correct. Using a very clever electronic vacuum meter that I borrowed from a friend the throttles were then balanced.
This would all have been a simple case of waiting for the day had I not got bored, started surfing t'internet and 'accidentally' bought a carbon airbox just to see if it made any difference!!
Here is a photo:
I measured the volume compared to the original airbox using water and it is 3.5 times its size thus theoretically offering superior power potential whilest retaining the original inlet trumpets so not as to upset the inlet runner length. It was clear that it would definitley help the airflow to the rearmost cylinders, something that has been well discussed on other 5 series forums. At face value it is a pretty well made bit of kit but this soon turned into a bit of a nightmare as it soon became apparent that the box would only fit a LHD car due to the positon of the header tank, PAS reservoir and other smaller issues. My initial anger soon turned into me getting the spanners out and I ended up moving the header tank to the other side of the engine, repositioning the PAS bottle and cutting a big hole in the airbox!! I made brackets that came off existing fixing points so no damage was done to the car and it now looks as 'factory' as possible.
I reshaped the underside of the airbox using some of my old laminating skills from when I worked as a boat builder during university and as a result it now sits very nicely with no clearance issues.
My next issue was to sort out the cold air inlet - two phone calls later I had an airfilter being made by ITG and a 102mm Silicone hose being made by Artel. Both of these firms are local to me and I can recommend them highly.
I decided to make an aluminium heat shield (on Pauls advice) which I managed to fit around the original space where the airfilter housing used to be, surrounded by some csl door trim that I had lying around. Again no holes needed to be drilled, only a couple of zip ties are needed for this.
The day arrived for me to head down to circuit motors next to castle combe and I arrived bright and early to get the UNICHIP fitted.
Paul arrived and ran the car up on his very flash new dyno to get a before reading and diagnose any issues that may be holding the engine back. To my relief all was well with the engine and I set to fittig the carbon airbox while paul wired in the Unichip - and what an invisible job it is too! Paul fitted a TPS and then ran wires to the ecu which he fitted neatly on top of the existing bosch unit - which on close examination still has all the Hartge serial numbers on it.
How the engine bay looks.....
After a lot of dyno runs (and fuel!) over two days the car was done and Paul was happy with the map and indeed the gains. To put things int perspective paul has had a couple of e24 M6's on here that made a maximum of 260bhp so you will see the results speak for themselves - in particular the torque!!
Before:
After:
Combined Change:
I have records from further back in the cars history where it has aledgedly put down more power (circa 326) but this was on different dynos so in this case it is irrelevant - the overall change is obvious.
The car is completely transformed and is genuinely significantly faster, this coupled to the nice sound track from the airbox has genuinely made it worth the effort. The car is more eager and pulls like a train, revving even harder than before. The midrange change is the most noticeable on an every day drive - this alone is worth the conversion. The car will now pull from idle in 4th at WOT with no complaints. Another plus is that the fuel consumption is better - I averaged just under 5 mpg better on the way home dring at the same speeds!
As you can tell I am pretty chuffed!!!! I can honestly recommend the Unichip and in particular Pauls skill when it comes to tuning it!
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Thanks , I will see if I can get a mate to film me doing a fly by. Its a shame I didn't video the dyno runs - it was incredible how much power Paul found on part throttles, 40-50 bhp in places - No joke!!
I think I know where my money will be going next; whilst I could spend it on getting the dents sorted out I think I would get more pleasure from the additional power and torque, and with a lhd M5 I won't have to modify the new air box.
Castle Combe is quite close to me so it will be interesting to see what a standard M88/3 apparently in good condition makes in comparison to your Hartge tuned engine, before, and hopefully one day after the changes
I would be very interested to see what a power a standard M5 puts down on Pauls rollers - Give him a shout and I'm sure he would be most interested as well. He can also diagnose any issues like vacuum leaks, bad ignition and compression etc which is always usefull as part of the maintenance regime.
I will bring it to Gaydon this year - I tend to alternate between the CSL and m5 each year!
Are there any UK M5 meets on the cards over the next few months?
A very interesting post as i have just bought the same carbon airbox.Should be here early this week.I know when i bought it that the fitment might be tight,if not very tight...Moving parts around are not a problem for me,but why will i have to cut a hole?
What gets in the way?
Also,will your strut bar fit back on?
Jimmy - Congrats! The designer admitted to me that it was only designed for LHD cars and that he made and assumption about the room in the RHD model. The airbox hits the bracket attached to the NS wing - the one that supports the bottom of the header tank and bracket to the air flow meter. You can just see how close it is in the picture taken from the side. It is very obvious how far off it is when you offer it up. The simplest solution is to take an angle grinder to the metalwork but I wasn't prepared to do that. The carbon work is relatively simple and doesn't affect the box at all.
Now I have modified the box it sits down very flat and the strut brace fits fine but luckily mine is an oval hartge one - if it had been round i would have had some issues.
Good luck with it and feel free to ask any questions - hopefully you can see from the photos where I moved the header tank and the PS reservoir. You will need a few metres of flexible heater hose, and some PS pipe to copy my locations.
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I see your car has a Hartge rear spoiler.Is yours Hartge tuned as well?(cams etc).
The Unichip sounds really good as well,better than fitting full stand alone system i think.Will it work with my ecu that has a Hartge chip,do you know?
When the car had an engine rebuild various hartge parts were used including the ecu but they opted for a pair of schrick cams - I don't know the reason why! Unfortunately the guy that built it (Mark Harper) now lives in Australia so I can't find out any definitives on the headwork which i know it had. It also has the full Hartge suspension kit including the antiroll bars.
The unichip will work with any ecu chip as it overlays its map on to the original - I would of thought the map from mine would be a great start. Hopefully Paul will chime in at some point to give some technical input on the unichip.
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