An unusual one.. BMW 535i Trackcar- MPG Maximising and Aero efficiencies...

[320touring]

Right, here's an odd one for you lot..

A fuel efficient Trackday car..

1989 BMW 535i Manual

3440cc, 12 valve 6 cylinder 211bhp

US MPG specs are 14 city, 21 highway, 16 combined.

The car has been bought solely for use as a track car- so is not restricted by the majority of everyday convenience factors required in a daily driver. however, it MUST remain road legal, so we can drive to/from the circuit..

I'd like to beat the City figure of 14mpg in overall use- this would be driving to/from the circuits PLUS the laps done at full pace. Even better would be getting to the combined figure of 16US MPG..

So far, the car has completed 1 track day and covered 129.4 miles- including 34 laps of a 1.3 mile circuit.

The tank was filled prior to the start and contains 80L of fuel.

We currently have more than 1/2 a tank left, so will look to use that for the next trackday.

I'm after any suggestions you may have around weight saving and aero enhancements that would improve it's performace on the track (better acceleration/braking due to less weight) and better economy (aero for travelling to/from the circuit?!)

Please see the next few posts for details of what's been done so far- including plenty of pictures

Thanks in advance,
Neil

[320touring]

This is a shared project between myself and my brother- We’ve been on a few Track Scotland Trackdays (in a Saab 9-3, my 318iS and the 320..) and have quite the taste for it, so decided to get ourselves a dedicated track beast…

The search was on for a cheap base car, so we could keep the build relatively inexpensive

Enter G775 CWK- forever known as the Five Shree Five.. :twisted:

This optionmeister came with the following delights:
3.5 m30 6cyl coupled to a manual box
LSD
Full Sport bodykit
Full Leather Sports Interior
540i Wheels
Air Conditioning
And a “Ghetto Drop”

As we got it






Progress so far:
Initial inspection shows that the Suspension and brakes are in decent condition- We’ve added ATE superblue and bled through. Car came with EBC Pads and grooved discs that were about ½ worn. :-D

We think the suspension is too low, but we’ll see how it fares on the next trackday.. :-?

We swapped out the 540i wheels (they went to a mate to keep his 520i off of bricks..) for a set of 15” BBS we already had. Decent tyres all round so should at least get a wearing out them.

Interior stripped out, ready for punting on for money for brakes/suspension/servicing



Once stripped out, it became apparent that we had the classic e34 problem- Rusty Sills! :sad:

The problem:


The solution:
Shiny new 1mm steel! :mrgreen:


The repairs are underway, but then we ran out of gas- so time to get re-stocked

Quick “ launch test” with my brother driving:
‪102 0508‬‏ - YouTube

So now we know a brakelight needs fixed too..

Things to Do :roll:

Finish Welding
Mount Bucket seats
Finish Sill welding
Diff Oil
Gearbox oil
Engine Service
Further weight reduction
Suspension check (bushes etc)
Exhaust Check
Sort some bodywork issues

Should have an update on Sunday evening after the weekend

[320touring]

Right, Quick Update…

After much to-ing, fro-ing and grinding, We now have something approaching sills..
I’ve only recently learned to weld, so it may not be too pretty, but the metal is firmly joined all the way round, and is a damn sight more solid than previous.
The welds have been seam sealed and primed/painted.

As can be seen, there appeared another hole in the passenger side- looks a fairly straightforward patch job- a lot less forming required than the interior stuff so far..








Does anyone know the part number for the floor bungs? Reckon they need replacing..

my bro stripped and lightened the front bumper- removing the side brackets. One was broken and the bumper was hanging down, so a “less than elegant” mounting solution was devised. Now no dropped bumper! :razz:


The fog lights have been removed too- and will probably be up for sale shortly- think we’ll use the gaps to duct air to the front brakes.
I’ll need to get a gold account and get some stuff up for sale.

Brake light issue has been resolved, so just the Rear Lights left to fix

Additionally, We received some bloody good news..

The previous owner contacted me via email after he saw the interior up for sale..
In summary (he was on the phone for 25 mins!), The car had a coolant leak recently, so he replaced the following items just prior to deciding to trade the car in:
Headgasket
Head bolts
Water Pump
Chain Tensioner
Chain
Thermostat

This is indeed good news- means its all the more fit for tracking!

We now have 1 weekend left prior to the track day on the 21st July..

Things to Do :roll:
Finish Welding (Small patch in Passenger Floor)
Diff Oil (level check and top-up in the LSD if required)
Gearbox oil (level check and top up (ATF FTW!)
Engine Service (New oil, air filter, oil filter,Plugs)
Further weight reduction (Engine bay, boot, further interior stripping)
Suspension check (bushes etc)
Sort some bodywork issues (some rust and painting needing done)
Rear Lights

All in all, still plenty to do!
:grin:

[320touring]

Had a proper weekend at this old bus!

First things first.. invent new and interesting ways to get to the diff for an oil change and level check..

Certainly more of a beast than the small case diff on my 320!
Plenty oil over the diff (hence cleaning product in Bro’s hand..) Topped up with LSD oil. Reckon it may need a touch more..and possibly the speedo feed replacing to stop the leak



Next up was a service, so it got nice new 10w40 semi synth, new oil filter, and an Air filter fitted (car was missing the air filter box). We just fitted a universal one until we’re able to track down an m30 one. Carried out a coolant/ Clutch/ Brake Fluid check and topped up as required

I got tore into the bodywork- Essentially only trying to make the car look decent from 10ft- less likely to attract any unwanted attention from law types..

The painting is not superb- rattle canned FTW.. but it does (almost) match, and makes the car slightly less “ratty” looking.. Up close its still a bit ropey, but more than serviceable for track work
Rear Quarter



Bottoms of the doors



Bootlid/Spoiler




Bonnet




Lots of Loom tidying was then carried out- getting everything tidied out the way, battery clamp fitted etc.. My brother did this as he’s more patient with cable ties than I! Additionally, the headlining and sunroof motor/switch was also removed.

And finally a paint of the interior floor, then re-fit the front seats. The bucket seats will have to wait until we get a set of e34 mounts to fit them to.

As it stands, the old girl is ready for a trackday.. 21st July will see her out at knockhill

Cant wait ! (apart from the £100+ to fill the tank..)

[320touring]

So the 21st came, and we brimmed the tank and set off for Knockhill..
Total mileage travelled 129.4
Total Laps done 34- Track length 1.3 miles
Fastest Lap (timed using “ye oldie stop watch” method) 1.15 at average speed of 62.5MPH

Car ran for a total of approx. 1hr 20 mins out a 2 hr session. There was lots of traffic as we were probably the 2nd slowest car there (faster than Nickso!) so spent a lot of time getting out of folks way. As per usual, the driving standard was high, with everyone being courteous
Mechanical Maladies
Wobble from front under braking early on- a trip to the pits and some wiggling/re seating of wheels seemed to cure it-very odd. Other than that, it was well behaved!

Videos

http://www.youtube.com/watch?v=9RvrmGR_Ihc

http://www.youtube.com/watch?v=5F5ETtCtvv0

http://www.youtube.com/watch?v=pZ6IAx1N7_Y

Pictures










All Flat out images courtesy of JohnS at
TrackScotland July 2011

All other pics from Smabo at TS July 2011 pictures by smabo - Photobucket

A couple of pics of Nickso in his e36 318iS




All in all, an awesome evening out, and less than ½ a tank used!

Things to do for next trackday:

MOT...
Suspension Refresh (dampers appear to be mismatched to springs)
More weight reduction (interior)
Weight Reduction (engine Bay)
Driver weight reduction :?
Possibly get more track orientated tyres (depending on budget)
Datalogger?

[cleanspeed1]

I want you guys to get a couple of cans of POR-15 and do the undercarriage in it.

Blows Waxoyl and other products into next week.

It's not cheap, but hopefully there is a UK distributor for it.

Here's a link, check it out.

POR15, Inc. - Stop Rust Permanently - Repair Gas & Fuel Tanks

The other thing I would do is install a wideband O2 sensor on that thing so that you can see the fluctuations in the AFR.

Time for a rolling road session and remap?

+1 on the driver weight reduction, Lord knows that I could use an improvement on my own power to weight ratio!

[Fr3AkAzOiD]

Looks like your damn near on the bump stops with that "ghetto drop" when taking the corners.
Were aftermarket lowering springs installed or did the previous owner just cut the stock springs?

If this is a dedicated track car you may want to look into an A/C delete and underdrive pulley for your alternator.

Wheel bearings still in good shape?

A quick release undertray would help smooth out airflow under your car as it looks pretty rough under there. That would improve aero drag and help both with MPG's and on the track.

Whats speeds you hitting in the straits? Only asking cause I've seen other peoples vids from that track and almost everyone looks slow on the strait after that tight corner.

[320touring]

Originally Posted by Fr3AkAzOiD

Looks like your damn near on the bump stops with that "ghetto drop" when taking the corners.
Were aftermarket lowering springs installed or did the previous owner just cut the stock springs?

If this is a dedicated track car you may want to look into an A/C delete and underdrive pulley for your alternator.

Wheel bearings still in good shape?

A quick release undertray would help smooth out airflow under your car as it looks pretty rough under there. That would improve aero drag and help both with MPG's and on the track.

Whats speeds you hitting in the straits? Only asking cause I've seen other peoples vids from that track and almost everyone looks slow on the strait after that tight corner.

Cleanspeed1- I'm hearin ya!, but POR15 can wait- more pressing things, plus can kkeep it in my unit to minimise further rusting

Freakazoid, yeah we're after a new suspension setup-looks like possible cut springs, but isnt actually too bad TBH. looking at a slight raise and componant refresh on the double wishbone setup on the front..

The A/C setup will come out- compressor should yield some good KG's, not to mention a few £££ when sold

Car still weighs over 1500KG, so plenty of room for weight saving

Agreed re the undertray- the underside of the car is anything but clean- its building something we can drop easily at the track that'll be difficult

As for speeds on the straight- we were hitting indicated 105 on the drag up the hill- corner speed at the hairpin is approx 27mph..Some of the folks in the Evo's and Nissan GTRs were hitting a TRUE 140+ before braking..

cheers for the input!

[mcrews]

I got your ducting for the brakes!!!!

Not sure what you have in the way of 'hardware/home improvement stores" but there are pictures of the items as they look on the shelf.

http://ecomodder.com/forum/showthrea...kes-18011.html

I am really enjoying your posts.
I raced a 1979 Mazda RX7 many yrs ago in SCCA Showroom stock Solo II. (racing solo in large parking lots laid uot with pylons/cones)

[320touring]

Originally Posted by mcrews

I got your ducting for the brakes!!!!

Not sure what you have in the way of 'hardware/home improvement stores" but there are pictures of the items as they look on the shelf.

http://ecomodder.com/forum/showthrea...kes-18011.html

I am really enjoying your posts.
I raced a 1979 Mazda RX7 many yrs ago in SCCA Showroom stock Solo II. (racing solo in large parking lots laid uot with pylons/cones)

Sweet re the Ducting- we're planning to cobble something like that together- its a heavy old car to pull up!

Sounds like you did what we call "Auto testing"- that stuff is far too skillful for the likes of me.. sounds like a sweet car you had though- was that one without the Rotary lump?

I'm also thinking that we'll reduce the tyre sizes on the car drastically- the 225/65/15's are HUGE bits of rubber, and wheels could do with being as light as possible..thinking 205/50/15s

that would give a circumference drop from 83.3 to 72.5 inches..

What do folks think?

I know it'll throw out the speedo, but thats not too important- we're measuring mileage by using the following methods:

Known Fixed distance to/from track (Google mapped, then verified using my 318iS mileometer)

Known distance of track x number of laps.