Rotrex BMW Mini Race Car

[Floof]

In September 2010 myself and a friend decided to build ourselves a Race mini, we didnt quite expect to take things this far...
I will just post the key points from the build - we have hundreds of pictures but below is a basic timeline of the build so far - all comments welcome

Current Spec
Engine
K&N RU 2820 Air Filter 3" outlet
Solid 3" pipe to Rotrex
Rotrex C30-94 - 90mm Pulley
GRS Custom Front Mount- Garrett Core 10 x 7.9 x 3.5"
Greddy S Recirculating BOV
GTT 63mm Throttle Body
Thumper Ported Inlet Manifold
Ric Wood CNCHeads Head: Stock Inlet Valves, +2.0mm GS Valves Enlarged Exhaust Valves
Uprated Valve Steam seals - Custom modified E30 m3 uprated ones
Crower beehive Valve Springs
Crower Titanium Retainers
RMW Race Cam v3
850cc Bosch Motorsport Injectors
NGK XXX Spark Plugs
Stock Head Gasket- copper ones too to raise or lower compression if we need/want to
RMW Arias Pistons 9.25:1 Compression
RMW Conrods
Balanced Stock Crank - Ricwood
Mahle Motorsport Bearings
Clutchmasters FX 400 clutch and Flywheel
OS Giken LSD
Driveshaft shop 450whp driveshafts with Rubber sealed bearings
Baffled Sump with Dimple plug
Twin Mezziere Controlled Hi Flow Water Thermostats and housings
Oil coolers for Rotrex and Engine
HEL oil lines with Magnom in-line magnetic filters
Tony Law Custom Race Manifold & Exhaust Mild steel for testing, when happy will be replaced with stainless system
Steve Lancaster ~30ltr custom foam filled race tank with roll over vent
Holley Red LP HV lift pump
Aeromotive HP Fuel pump
Jegs fittings and hose -8 to -6 return
Aeromotive Platinum Adjustable Fuel pressure regulator
'brownfloof' fuel return system with Aeromotive Low and High Pressure Filters
1320 Fuel Rail
GRS Water Radiator - boot mounted with Spal pull fans x 2 (13.5'')
1320 Standalone ECU EC2 PNP
Cosworth 3 bar Map sensor
Matt Faulks - TDF - Race spec wiring loom

Chassis
Steve Lancaster / Pro Speed Custom T45 Welded Roll Cage
Chassis Seam Welded by Steve Lancaster
Shell Body work lightened - removal of extra skins etc
Powerflex Poly bushed wishbones etc
1320 / Vibratechnics solid Engine and Gearbox Mounts
BSH lower Engine mount

Suspension
KW 2-Way Race Coilovers (mini challange) 698 lb Front and 900 lb Rear springs (Eibach ERS springs of various weights for setting up)
R56 rear trailing arms - 2kg lighter per side
Steve Lancaster Re-enforced Caster Adjustable Strut Tops
IE 22mm Rear Anti Roll Bar
Mini One 17mm Front Anti Roll Bar
KAV Motorsport upper and lower rear control arms
TSW adjustable drop links Front and Ireland Engineering rear

Brakes
OEM R56 'S' Calipers Front
Performance Friction 2 piece discs 294x22mm
Carbotech xp12 Pads
OEM Rear Calipers
Brembo drilled rear discs 259x10mm
Carbotech XP8 Pads
HEL complete braided lines
Orranje Challange brake ducts

Changing to AP racing brake set up this year

Wheels and tyres
17x8" ET35 Kodiak 3 piece Forged x 4
17x9'' ET 20 Team Dynamics x 8
Copper coated Steel Wheel Nuts
85mm Stud Conversion hubs
Multiple slicks / wets / inters

Interior
Steve Lancaster Prepped
Flocked Dash
Racetech gauges for Fuel level /Oil pressure /Oil and Water temps/ Revs
Sparco Evo seats set as far back as possible on custom rails with TRS harnesses
AP Racing Peddle box & reserviors
Compbrake Hydraulic handbrake
Custom Steering Column set back XXXmm
Gear stick raised and moved back with Shortshifter and solid mounts - 150mm higher and 170mm further back
Lengthened gear cables
1.2mm Aerospace Alloy Door Cards
Mikroh 900Amp Race Battery 0.6kg
Heated OEM front screen

Weight Saving
Plastics4performance lexan windows
Orranje Race Bonnet
Orranje Race Boot
Orrange Race Doors
Orranje Challange Front Bumper
Shell completely stripped of all non essentials skins and brackets

Aero
LRS Custom Flat floor
LRS Custom Rear Diffuser
LRS Custom Front Splitter and Engine Guard
Twin element Adjustable rear wing

Misc
Custom Side Air intake ducts - for the radiator
Modified wider arches
Hella 90mm headlights
Twin PIA light weight horns
FIA Rain light

It started when brownpants saw this and we picked up a completely bare shell from Glasgow - Scotland


Started cutting as much out of the insides


Then we took the car to LRS motorsport fabrications, which turns out to be the best thing we could have done for the build, and where it went from more of a 'fun' project, so a serious and fun project.


Drawing of cage idea


Which turns up like this


Most of cage tacked into place




The quest for trying to save weight got serious, here the rear panels have been removed to allow all non essential metal to be taken out


We decided from the start that we wanted to have a rear mounted rad to help distribute the weight, below is the cover and the first two ducts in place, we have since added a further 4 NACA ducts to help with cooling


Interior painted in fiat baby blue with 50% white added


Exterior Painted in Renault Racing Blue


Caster adjustable top mounts are made (caster is set at minimum in this pic)


Driver cooling solution



Made the A-panels and sill all one piece


Custom made GRS intercooler



Few Exterior shots after some stickers were added.






Exhaust Heat Wrapping




Holes drilled in rear window for better circulation of air in the car - keep us cool in the mega UK heat lol


aero mods - reduce drag



Steering pump moved to the rear of the car to help weight distribution


The silver block is the in-line Magnom filter which is extra to the normal oil filter . It T's off through the bulkhead to the Accusump


Here's the Accusump ( used to keep oil pressure up if it drops below a pre set level )


Brake Ducts


First Rotrex Header Tank


Extra ducting to our rear mounted radiator from two NACA ducts on the rear windows



Ecu location


Header tank, (different hose now fitted) with two meziere inline thermostats


Flocked door cards made from 1.2mm aerospace alloy


Accusump boxed in with a Perspex window for the gauge.




The car went back to LRS to get some more bits and pieces finished off

Splitter




Oil Catch Can


Widened Archers to allow us to use 17x9 wheels with 235 dunlop slicks (touring car size)


Switch Box



Diffuser



Flat floor


From the front




Splitter


Undertray/ flat floor


Diffuser


Under car floor off



Time to Tune it:



On thursday morning (02/02/2012) Nige and I arrived at 1320 to get the final tune on the car, since the last time the car was on the dyno the engine was rebuild to put in our mahle motorsport bearings and new piston rings as the old ones werent gapped correctly, so first thing we done was seat the rings. I was well excited as I got to drive the car on the dyno to do this, nige is a cock though - we all knew that...

[media]http://www.youtube.com/watch?v=4KNT6b19o-0[/media]

so this was completed, oil dropped and new stuff put in. The davis craig waterpump had not been connected to the ecu yet so this was done prior to mapping starting. It was now we started to get a kettle issue and it happened every time the electric pump would kick in at a preset temperature. After much trouble shooting we have binned it and now just running a stock waterpump which is working well. Not going to tell the full story as its pretty boring but the cars water temp wouldnt go above 55c no matter what we done so this is an issue that is being addressed.

so onto mapping and the car just sounds like its going to be a beast. no issues until we start to map on boost and higher revs. The slicks were not getting hot enough and were wheel spinning on the dyno, so we borrowed some R888's and went back on with the same issue. We then did a few more things and used 4th gear for the dyno pulls.

Mapping mapping mapping...





Here is what we are left with, mapping is not yet complete and we have another 1200rpms to go, the map upto the 6800 is not yet complete as we ran out of time due to all the issues the car had over the past couple days. So we have left the car at 1320 to get finished off before Nige goes and picks it up in march or something.

336 whp and 259 wtq @ 6800rpm and 21psi boost - on tesco 99 - no methanol.



Note: the car is fking loud, we are going to get a new exhaust system made in stainless with more silencers etc to tone it down a bit.
Dyno Video - 6500rpm
[media]http://www.youtube.com/watch?v=RM5MaevGb9k[/media]

[VidalBaboon]

[BelperJim]

Wow looks like fun! I probably missed it but how much does it weigh?

[clubracing]

Looks like a great project but what are you planning to do with the car? Due to the modifications you've made it's only eligible for a very limited number of race series and I don't think any that it would be competitive in.

[bakerstreet]

clubracing said:

Looks like a great project but what are you planning to do with the car? Due to the modifications you've made it's only eligible for a very limited number of race series and I don't think any that it would be competitive in.

I was also wandering the same thing. What are you planning on racing it in? Sprints?

Its still an interesting project though. I will bookmark to keep an eye on progress.

I see you have added the fins on the bag of the roof to reduce drag. Surely, they are there for stability and not for drag. Also, fairly pointless worrying about derag, when you have put that massive spoiler on the back

[Classic Grad 98]

Looks like a very professional build.
I will echo the views of 'Clubracing' and 'Bakerstreet' on the intended series and aero though, was thinking the same.

[Floof]

Not had its final weigh in yet but I expect it to be around 920kgs.
We will be racing it in time attack / eurosaloons / CNC Heads championship where it is eligible and will be very competative

[bakerstreet]

Floof said:

Not had its final weigh in yet but I expect it to be around 920kgs.
We will be racing it in time attack / eurosaloons / CNC Heads championship where it is eligible and will be very competative

And the Aero?

Hope the car is competitive and you get some trophies

[Floof]

bakerstreet said:

I see you have added the fins on the bag of the roof to reduce drag. Surely, they are there for stability and not for drag. Also, fairly pointless worrying about derag, when you have put that massive spoiler on the back

The 'fins' are airtabs, and the wing is there as an experiment at present, set at minimum and not to try and create downforce but rather to try and clean the airflow at the rear, if this one doesnt work we will make one that just extends the roofline backwards ala FWD drag cars.

[Greg_D]

it looks nicely done, you have certainly emptied the piggy bank in it's general direction

[pthelazyjourno]

Pics not showing up here?

[P I Staker]

Fantastic build, proper job.

[anonymous-user]

Floof said:

bakerstreet said:

I see you have added the fins on the bag of the roof to reduce drag. Surely, they are there for stability and not for drag. Also, fairly pointless worrying about derag, when you have put that massive spoiler on the back

The 'fins' are airtabs, and the wing is there as an experiment at present, set at minimum and not to try and create downforce but rather to try and clean the airflow at the rear, if this one doesnt work we will make one that just extends the roofline backwards ala FWD drag cars.

Significant downforce at the rear on a fwd race car is actually a really good idea. it allows you to alter the balance of the car as speed increases. At low speed you want a pointy darty FWD car, to help you get into and out of slow hairpins cleanly etc. But generally the high lateral stiffness you have to engineer into the rear suspension to do this makes the car unstable at high speed. (lets face it, a dab or two of oppo at 50 or 60mph is fun, at over 100mph it's a bit more focusing ;-)
So you use the rear wing to move the effective centre of pressure backwards as speed increases, helping to keep the rear in line in high speed corners (where due to the high gear, you don't have as much tractive effort and hence front tyre loading to battle with etc)

[Bungleaio]

I like that a lot.

[roosterracing]

Well it is my car now and it has undergone massive changes since any postings on here!

It is now turbo charged with a Garrett GT2868 HTA hybrid turbo from Owens Developments and had no end of problems which hopefully have now been put to bed.
It is sporting a new i88 Vipec ECU which hopefully should solve most of the problems or at least help to find them before they happen.

It ran well when tested 18 months ago but the turbo died after hot oil killed it but we'd had to change the Compressor housing before that due to surge and that probably weakened it anyway. Sadly the ECU logging function failed AGAIN so it was binned off and a new route taken with mapping etc. At that stage Floof had enough so I carried on alone .

Been a slow, very hard time with it but it gets its first test again at Anglesey in a couple of weeks.

Full bladed roll bars and custom wishbones and control arms have been added too , ATL fuel cell, new Inlet manifold plenum, all new sensors , wiring looms ,