BMW 325iS Evolution HP

[Can-Am ZN]

back when those cars were racing I worked at TBS Auto on the dyno, we reprogrammed the ECU and dyno'd Robbi Smith's race car as well as a few Superboss Opels including Farook Dangor's racing Superboss, enjoyed those days. I worked on quite a few Group N cars as well as 2 Porsche Turbo Cup race cars as well as a lot of other different race cars.
On all the Group N cars the new tyres would be dropped off at TBS and we had a machine that would shave all the rubber down, the various teams would ask us to shave the tyres to their requirements and I think the maximum tread depth was around 3mmI used to cringe seeing all the new brand new tyres getting shaved .

Gavin I must get a friend of mine to register on your facebook 325is group. I just re valued his IS for insurance, original unmolested mint condition 1991 BMW 325 is, full service history, has all books , tools original spare and mileage is around 85k, he only drives it once a month then locks it away as he keeps getting bugged from chancers wanting to buy the car

Thats very interesting, Gav. Yup, I witnessed the tyre shaving too

I can relate to the experiences of your buddy...its very annoying actually!

Dont suppose you can remember what power the Group N cars were making, do you?

Also, any idea where I can perhaps get a copy of that Group N EPROM?

[KSF]

Dont suppose you can remember what power the Group N cars were making, do you?

Bearing in mind that the GrpN engine rules and their interpretations (and level of cheating) were ever moving goal posts.... I think at the time of the EvoII the guys were getting around 15-20% more wheel hp than the showroom cars. Figure of around 125hp at the wheels at reef altitude comes to mind, but it could be completely wrong, I don't clearly remember.

GrpN started out as "N"early standard and cars were very close to showroom stock in '86 or so, maybe 5% increase. By the time the Nissan Maxima V6 raced, they were getting substantially increased power out of specially built engines that spent many hours on dyno's to extract the max. I am not sure who got the most, but the Maxima (a nominal 140kW car) were reputed to have some 180kW in race trim.

[Gavin RS]

Hi Guys

I remember the figure on the dyno at 112kw to 114kw on the wheels , this was on 2 of the group N 325 is's.
I had done around 6 road going std cars by then and the difference in driving the race car compared to a road car was huge,
I also tuned a road going Super Boss , 1 of the first batch with Cosworth head we played with different exhausts, ended up with leaving the std branch as you could get no better but the rest of the system was Brospeed and then I did the chip and cam timing, this car made over 100kw on the wheels.

Unfortunately my old Boss Paul von Lingen passed away last year and TBS was closed a few years ago which is sad as I had access to the dyno anytime for my own cars. I wish I had kept copies of the various e-proms for the BMW and Opel's

It was interesting back then, when one of those cars came in, first thing before a run was do a full check, all plugs, air filter , oil and coolant levels etc a proper power run was then done and the info recorded. then remove chip and plug in the e-prom. check for full throttle, the car was run numerous times until the programming gave the best results, timing curves and fuel curves ( we had a 4 gas analyser) then the info was installed onto a new chip and put into the car and a final run done and recorded,it was around 2 hours work. proper computer printout of results, no hand written figures and corrections etc. Paul gave training and helped quite a few people in SA with dyno set ups.. .

Pauls dyno to me was the best and most accurate around as you could read power outputs at 50 rpm increments. the 4 gas analyser was calibrated every morning and the Hoffmann dyno was calibrated very often. Once a car was on the rollers it was strapped down properly and a massive fan was fitted in front , not a normal fan like most but a huge drum roller fan, so airflow was no problem, exhaust extractor , and another fan blowing onto the engine to simulate temps at highway speeds. No car was ever revved to the limiter as you could see the power and torque curves on the computer to see where power dropped off.
Paul was a genius when it came to tuning bikes or cars, and was brilliant with electronics. made me spend a weekend setting up multiple webers on a Lamborghini so I could learn properly. What a way to learn

I must find my old workshop book with all my information from those days.

[barrydorr]

I missed this tread earlier, thanks for sharing the info...great learning some more about these special cars and their History.

I am glad i have bought the winning car though...

[Can-Am ZN]

...I am glad i have bought the winning car though...

Yeh, we lost 3 years to 1 to those damn buzzing 4-pot rattle-traps

Here's quite an entertaining, recent CAR magazine comparison feature of the two, with Chris Harris and Deon Joubert:

https://www.youtube.com/watch?v=74QIHOyJD9U

[barrydorr]

Had seen that video..
Hope to take my supie on the track one day.

Want to go for a race with you bmw and to the test ourselfs?

[Can-Am ZN]

Had seen that video..
Hope to take my supie on the track one day.

Want to go for a race with you bmw and to the test ourselfs?

You really must make an effort to do it, Barry...you'll have tons of fun!

Just beware of the LSD on the Supie...when it hooks up as you accelerate through a bend, be prepared for it to want to tug you into the bushes coz the LSD largely nullifies the self-centreing effect of the steering wheel and you will have to turn the steering back to straighten out after the bend!

Yes, I would love to give a Supie a go at a trackday to rekindle the old Group N nostagia! I'm sure it will draw a LOT of interest and excitement from the spectators

There are just very few SuperBoss owners who seem to be willing to track their cars..

[barrydorr]

I have a lot of gokarting experiance and was quite fast in the kart. I have however never raced on a real track in a car...and would love to do it. Racing with fwd drive is surely challeging specially when cornering.

So if if you are game we have to see if we can make it happen, i am for sure game..if i would break the car i can fix it again. There a few superboss owners who also have a track car but keep their road supie on the road.

[Can-Am ZN]

At Zwartkops Raceway:

[barrydorr]

Nice!

When do the hold trackdays at zwartkops?

Just getting excited now to bring my car out there, seeing yours...but my first excuse for loosing will be i have never done it before...lol