2017 prep - Weight results for my TIs

[BlackBMWs]

These are my novice notes to share. I'm not so knowledgable on weight tuning, but I am intending to learn much more and apply it this season. Not much education in tuning yet, I just like to drive. I am posting this for reference for folks in the event anyone is interested.

So, last year was a more active track season for me with 11 days of track days and 7 AutoX days. ThunderHill, Auto Club, Laguna Seca and events with 2 regional Porsche clubs. Fun overall for my novice start. I had run 3 or 4 events of some sort in previous years, but last year was more immersive and consistent weekend fun.

I took one of our TIs and set it up for a street legal, weekend track car. I went with tires and suspension as my main improvement strategy along with grippy seats. The only engine mod for the stock M44 engine was to front Fogg the air box. It also benefits from a Stromung exhaust.

I noticed by the end of the season more of how the TI was handling. Predictable oversteer and faster lap times when I had a passenger in the car. I wondered if the balance in the car could be off. I worked to lighten the car, but I was faster through turns with more weight. I understand the benefit of downforce, but running with my wife in the car simply to get better laptimes seemed counter intuitive.

I weighed my M44 and S52 TIs this last weekend. The M44 was the car I used in 2016 and the S52 will be used this year for Track and AutoX events.


The scale system consists of four scales, one for each tire, a control panel and interconnecting cables. The scales read the weight present at each tire, displays it and calculates the % of weight at each corner. Then it is able to present that data in a few ways: Total, F/R %, side to side% and diagonal corner to corner.

I post those readings for both cars in pounds. It can also present in Kilograms. I also took another set of weight readings with me in the drivers seat to see the balance changes with driver and helmet. I can post those if anyone is interested.



First set of numbers are for the 98 M44 Cali Sport, 3/4 tank of gas, no driver. Rear seats removed. CA Tuned Coliovers, F/R Mason strut braces, X brace, racing Dynamics F/R sways, Z3 steering rack, Style 68 staggered with RE71s, Bride Low Max bucket seats E36 vented front rotors, 525 rear calipers, Hawk HP+ pads. Front fogged air box and Stromung exhaust. Spare removed.



Total weight -


Front vs. Rear weight balance -


Right vs. Left balance -


Drivers side front to Passenger side rear -


Drivers side rear to Passenger side front -


What was interesting to me was the F/R % in that the % up front was higher. Made sense as I pulled out the spare, its holder, stuff in the tool kit, rear seat and panels and only added a light rear strut bar.

In retrospect, I wonder aside from lightening the car, if a CF hood help balance the car out to a material advantage?

The other thing was it was heavier than I thought. Then thinking the thicker sways, x-brace, bigger calipers, strut bars all add up. I did lose about 64 pounds tho is swapping the stock Sport seats for the Bride Low Max buckets. My goal last year was to handle with the Miatas on the track. By the end of season, the TI ran well with the Miatas and WRXs. I was able to out corner and out brake most others bigger and more powerful cars in my grouping. Of course I got blown away in any longer staightaway. I got good at the pointed finger in those cases, only to be a nuisance again in the twisties.

I want to take any observations and learning to the S52 TI for this season.

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1998 TI Sport w/S52 - 1/2 tank full, mostly stock, nothing really removed yet, K1 16x7 w/RE-71s square, x brace, Megan front cross brace, CA Tuned Coilovers, Subwoofer. Alum radiator. Spare removed. Fan delete, 16" electric fan, Borla exhaust.



Planned mods: Strip interior and replace sunroof cartridge with fiberglass insert, Z3 rack, caliper and pad upgrades, HR sways, a rear Mason brace/harness bar to be replaced with rear cage later, Bride Low Max buckets and 6 point harnesses, diff swap, CF hood, alum door panels, alum expansion tank.

Yellow and Red plastidip as well.

Total weight -


Front vs. Rear weight balance -


Right vs. Left balance -


Drivers side front to Passenger side rear -


Drivers side rear to Passenger side front -


My last total S52 reading in KG for Samdemange.



My target for the S52 is 125 pounds lighter and better F/R balance after the mods.

I'll weigh my Wife's Ti for comparison as it is more stock than these other two. Just suspension upgrades.

I am just learning tuning considerations and will always welcome comments and experiences.

Cheers! Rich