F82 M4 light weight measurement and Road Atlanta review observations

[FTS]

Originally Posted by karussell

sounds like you have some ideas of your own. would be great to hear your feedback if try it out. just get a baseline first.

Totally educated guesses, nothing informative, your on-track feedback thus far is the most informative as expected. I am going to use your data as baseline frankly (do you have a data logger at this time, I have the Solo DL)

I am with you and rsr racer, one thing at a time. I am currently thinking of the wheels and tires; unless someone makes a case otherwise I am thinking of getting 9.5x19 front and 11x19 rear wheels with 265/35 and 325/30 R888 tires (will do test fitments first of course). No spacers for the track, but probably 10mm front and rear for street. Once I have a feel for the wheel/tire combo, I was thinking the KW HAS as you have been as well, but first I want to test the spring rates. Everything you and racer20 said thus far makes me confident that the adaptive shocks will do just fine for DE purposes.

If there are any items you want me to test at all, just say it, so we don't do redundant stuff as we learn this.

How about we do a test and tune day (or two) early spring? VIR? Everyone that wants to attend, and we collect data along the way and compare notes on the track, may be some A/R sets will be out by then as well for balance tuning

[karussell]

Originally Posted by FTS

Totally educated guesses, nothing informative, your on-track feedback thus far is the most informative as expected. I am going to use your data as baseline frankly (do you have a data logger at this time, I have the Solo DL)

I am with you and rsr racer, one thing at a time. I am currently thinking of the wheels and tires; unless someone makes a case otherwise I am thinking of getting 9.5x19 front and 11x19 rear wheels with 265/35 and 325/30 R888 tires (will do test fitments first of course). No spacers for the track, but probably 10mm front and rear for street. Once I have a feel for the wheel/tire combo, I was thinking the KW HAS as you have been as well, but first I want to test the spring rates. Everything you and racer20 said thus far makes me confident that the adaptive shocks will do just fine for DE purposes.

If there are any items you want me to test at all, just say it, so we don't do redundant stuff as we learn this.

How about we do a test and tune day (or two) early spring? VIR? Everyone that wants to attend, and we collect data along the way and compare notes on the track, may be some A/R sets will be out by then as well for balance tuning

woh 325 on this car? haha well kudos if you can get them to fit. thats the size used on the GT3 RS and its rear weight biased. still considering this car easily has more torque and less weight in back to get it down maybe it is enough tire for the rear. i kinda doubt it will clear the . Isn't a 11 too narrow for a 325? oem wheels on the GT3 RS for that width tire are 12's.

The test and tune day at VIR I'm all for. Actually we can see about reserving the course and have an all BMW ///M day.

[EdR]

Originally Posted by karussell

The alignment is untouched so far. We are getting in the KW height adjustable coil system for adaptive shocks and will corner balance along with adjust toe settings. I think we will just stick to factory settings on toe for now. one variable at a time if at all possible.

karussel .. Have you installed the KW HAS by now and formed any impressions?
Really appreciate your informative reviews and the time/effort you put into them.
Thanks

[Paul2x]

Love this!

I did the same with my GT3. Have a spreadsheet with weights of everything.

Don't forget to drain and/or remove the Washer Fluid! Easy 7-10lbs!

Thanks for posting, this is the data I like to see!

Keep it up!!

[stressdoc]

I'm thinking the 275/295 stock set up was chosen in part because of fuel economy.
I am an unsprung weight freak, so not a big fan of bigger wheels & tires.
I am very impressed with the adaptive suspension, in particular how damping micro-adjustment is independent at each wheel.

[zosoboogie]

Nice I can't wait to run with Chin again!

[w00tw00t]

great review thank you but you need to resize your pics - was very hard to read with the massive images you uploaded

[karussell]

thanks guys. sorry about the image size. didn't realize they were not auto sized for the page. i'll have to photochop them down.

[Diver]

Running on the 18" wheels, hmmm...

[mtrack]

Originally Posted by karussell

stock seats especially with the fabric hold you in quite well. the bolsters are generous. its much better than the e9x design which in US form used the standard 3 series base cushion. i didn't find myself fatigued from holding myself in the seat. this car is just begging for some fixed back buckets, a roll bar, and 6pts though.

Excellent post, karussell, thank you so much for posting all of this invaluable information. I am currently debating between the F82 and F80 for two reasons.

First, this will be my 3rd M3 or, first M4 that I would track. I find the seating position and ample helmet room of the F80 M3 to be somewhat compelling. However, my understanding is that a slight nod goes to the M4 in terms of overall handling. The higher roof line brings the center of gravity up a bit in the M3 with a corresponding affect on polar moment of inertia. I don't mean to cast any aspersions on the F80. Both the F80 and F82 are viable options I/M/O.
Just wondering what you're impressions are of the two, and how they compare on the track.

Second, back to seating position. I'm 6'3" with a 34" inseam. I have long arms. I have sat in both the F80 and F82 with my Bell G2 helmet. The M3 has no interference regardless of seat back adjustment or tipping the entire seat fore or, aft. The M4 is another story. If i adjust the seat flat on the floor with the seat back adjusted for proper purchase on the steering wheel, there is minor helmet interference with the roof liner near the upper door frame. Mildly distracting. If I run the seat just a little forward, I begin to get major interference from both the top and side of the roof liner. Moving the seat further forward would be unlikely, but, it does limit some potential adjustment options. In the past I have always liked to sit as flat on the floor as possible. Much prefer the ability to individually control the lower cushion of the seat separate from the seat back. This could never be done in the M3/4 and, still can't with the current generation. After a couple of test drives in the M4, I noticed that it is really necessary to have the whole seat tilted slightly back to keep me in the seat. Luckily, I am friendly with my salesman and he let me take a few sharp diminishing radius turns to give me some insight. Although, I prefer to be a bit more upright. In the "tipped," orientation I do find the benefit of no helmet interference. So, karussel after this rather long winded description my question is: What seating position do you prefer in you're M4? I noticed from some of the photos you posted, it looks like you have pretty good helmet to roof liner clearance.

It's time for me to place my order. Trying to make the right decision. Thanks in advance for any feedback. It is greatly appreciated

[ihc95]

Also curious about the KW HAS system.

The M4 is looking more and more like the perfect car for me. Just waiting to try the GT350 before I pull the trigger.

Thank you for the awesome write up and review.

[kred]

what camera + lens was used for these rolling shots?

[M3ichael]

Easy on the oversize pics.

[karussell]

Originally Posted by mtrack

Excellent post, karussell, thank you so much for posting all of this invaluable information. I am currently debating between the F82 and F80 for two reasons.

First, this will be my 3rd M3 or, first M4 that I would track. I find the seating position and ample helmet room of the F80 M3 to be somewhat compelling. However, my understanding is that a slight nod goes to the M4 in terms of overall handling. The higher roof line brings the center of gravity up a bit in the M3 with a corresponding affect on polar moment of inertia. I don't mean to cast any aspersions on the F80. Both the F80 and F82 are viable options I/M/O.
Just wondering what you're impressions are of the two, and how they compare on the track.

Second, back to seating position. I'm 6'3" with a 34" inseam. I have long arms. I have sat in both the F80 and F82 with my Bell G2 helmet. The M3 has no interference regardless of seat back adjustment or tipping the entire seat fore or, aft. The M4 is another story. If i adjust the seat flat on the floor with the seat back adjusted for proper purchase on the steering wheel, there is minor helmet interference with the roof liner near the upper door frame. Mildly distracting. If I run the seat just a little forward, I begin to get major interference from both the top and side of the roof liner. Moving the seat further forward would be unlikely, but, it does limit some potential adjustment options. In the past I have always liked to sit as flat on the floor as possible. Much prefer the ability to individually control the lower cushion of the seat separate from the seat back. This could never be done in the M3/4 and, still can't with the current generation. After a couple of test drives in the M4, I noticed that it is really necessary to have the whole seat tilted slightly back to keep me in the seat. Luckily, I am friendly with my salesman and he let me take a few sharp diminishing radius turns to give me some insight. Although, I prefer to be a bit more upright. In the "tipped," orientation I do find the benefit of no helmet interference. So, karussel after this rather long winded description my question is: What seating position do you prefer in you're M4? I noticed from some of the photos you posted, it looks like you have pretty good helmet to roof liner clearance.

It's time for me to place my order. Trying to make the right decision. Thanks in advance for any feedback. It is greatly appreciated

First of all M3 vs. M4. I can't tell a difference between them driving. Both are completely mental. I do feel like I'm sitting higher up in the M3 with same seating position.

I have plenty of head clearance in either car but i'm 6ft. my codriver is 6ft6 and he fits in his stock 1M just fine with helmet. Maybe i can ask him how he does it for you.

My preferred seating position is fairly upright in this car but as low as possible. With your height i suggest regardless of the vehicle you choose to get your head as low as possible. 2 things happen. 1st you are forced to look up and not down in front of you. This is great for moving your eyes way down the track. 2nd its safer and lower center of gravity. In the race car we have cushions for each driver and i prefer to sit in a little more tilted position without pinching my legs. 1.5 hours in a race car at a time you want maximum comfort. So if driving with a slight tilt works for your comfort and you end up sitting lower looking up more then it sounds like a win-win.

unfortunately that won't help with your M3 vs M4 debate. good luck! can't go wrong with either or both!

[karussell]

Originally Posted by ihc95

Also curious about the KW HAS system.

The M4 is looking more and more like the perfect car for me. Just waiting to try the GT350 before I pull the trigger.

Thank you for the awesome write up and review.

I been following the GT350 as well. Price is right but its going to be tough finding one without a huge markup at least for the first year. also the weight of the new mustangs have me worried.

The HAS system is working well.
I will provide an in depth review once i have another track day on Road Atlanta. Its the only new item on the car and I want to review it purely on its merits while keeping all other conditions as near the same as possible.

Driving on street I will say the adaptive suspension works well with them in sport and sport-plus. I think they are a tad too much for the comfort setting making the car feel like it rebounds off uneven pavement a little too aggressively versus fully absorbing the bump. I have been driving on sport plus now almost exclusively as its my M1 setting anyways and I feel the car takes a set much more readily. feels very direct and responsive not that stock it did not, but it is noticeable. bumps don't seem to be much concern either. I figure I paid for the fancy shocks I will make them earn their keep.

[karussell]

Originally Posted by Paul2x

Love this!

I did the same with my GT3. Have a spreadsheet with weights of everything.

Don't forget to drain and/or remove the Washer Fluid! Easy 7-10lbs!

Thanks for posting, this is the data I like to see!

Keep it up!!

Yes yes yes! and people laugh when they see a digital food scale at my shop.
been driving with bare trunk for past month. don't see the need for all that mess in there!

[karussell]

Originally Posted by FTS

Totally educated guesses, nothing informative, your on-track feedback thus far is the most informative as expected. I am going to use your data as baseline frankly (do you have a data logger at this time, I have the Solo DL)

I am with you and rsr racer, one thing at a time. I am currently thinking of the wheels and tires; unless someone makes a case otherwise I am thinking of getting 9.5x19 front and 11x19 rear wheels with 265/35 and 325/30 R888 tires (will do test fitments first of course). No spacers for the track, but probably 10mm front and rear for street. Once I have a feel for the wheel/tire combo, I was thinking the KW HAS as you have been as well, but first I want to test the spring rates. Everything you and racer20 said thus far makes me confident that the adaptive shocks will do just fine for DE purposes.

If there are any items you want me to test at all, just say it, so we don't do redundant stuff as we learn this.

How about we do a test and tune day (or two) early spring? VIR? Everyone that wants to attend, and we collect data along the way and compare notes on the track, may be some A/R sets will be out by then as well for balance tuning

I have my racekeeper from my gt3. ran it in spa on the M4. didn't get to install it in time for road atlanta last time, but it will be placed in there very soon. Thats really more to work on my own line at the track however and maximizing what I have to work with.

I could subconsciously push less on stock or harder with the new setup and claim there is an improvement but that won't help anyone. I just share what I felt so take everything with a grain of salt. YMMV.

VIR sounds fun. I'm totally up for supporting it. the HAS system is really easy to work with. scales are portable. so is the grille! m3/4 bbq!

[Maddict3]

Great write up Jim! We need to do a reunion soon.

[mtrack]

Originally Posted by karussell

First of all M3 vs. M4. I can't tell a difference between them driving. Both are completely mental. I do feel like I'm sitting higher up in the M3 with same seating position.

I have plenty of head clearance in either car but i'm 6ft. my codriver is 6ft6 and he fits in his stock 1M just fine with helmet. Maybe i can ask him how he does it for you.

My preferred seating position is fairly upright in this car but as low as possible. With your height i suggest regardless of the vehicle you choose to get your head as low as possible. 2 things happen. 1st you are forced to look up and not down in front of you. This is great for moving your eyes way down the track. 2nd its safer and lower center of gravity. In the race car we have cushions for each driver and i prefer to sit in a little more tilted position without pinching my legs. 1.5 hours in a race car at a time you want maximum comfort. So if driving with a slight tilt works for your comfort and you end up sitting lower looking up more then it sounds like a win-win.

unfortunately that won't help with your M3 vs M4 debate. good luck! can't go wrong with either or both!

Thank you for taking the time to answer all the questions. So helpful.
You spec'd your F82 with the cloth seats. Do you think the driver might sit a bit lower in the cloth seats vs the leather? Does the bottom cushion compress more to form more of a "cup," with cloth than the leather? I know cloth material itself is less slick and grips better due to that fact alone.

Also, I'm very intrigued by the standard 18" tires vs the optional 19"s. I really don't care too much about the cosmetics of wheel to chassis gap. Is there any on track performance difference between the 18" tire size and the 19"? Obviously the cheaper the replacement cost for expendables the better!

[karussell]

Originally Posted by mtrack

Thank you for taking the time to answer all the questions. So helpful.
You spec'd your F82 with the cloth seats. Do you think the driver might sit a bit lower in the cloth seats vs the leather? Does the bottom cushion compress more to form more of a "cup," with cloth than the leather? I know cloth material itself is less slick and grips better due to that fact alone.

Also, I'm very intrigued by the standard 18" tires vs the optional 19"s. I really don't care too much about the cosmetics of wheel to chassis gap. Is there any on track performance difference between the 18" tire size and the 19"? Obviously the cheaper the replacement cost for expendables the better!

The cloth is firm as leather to me. maybe even a little more. I did not notice a difference in seating position with leather versus cloth. I definitely slide less with cloth though. I have two sons and they like to jump around in the car. The cloth is holding up quite well to 4 year old torture test.

There is no more wheel gap with 18's versus 19's. Actually the rear 275/40-18 tire is 0.1 inch larger diameter than the rear 275/35-19 so technically it has less gap than 18's. Fronts are same overall diameter. I like how the 18's look more. I can't tell driving a 19" or 18" wheeled car. If i want another set of 19's I can just call forgeline and get a set that is light, strong, and won't break the bank.

[FTS]

Originally Posted by karussell

VIR sounds fun. I'm totally up for supporting it. the HAS system is really easy to work with. scales are portable. so is the grille! m3/4 bbq!

Fantastic! Scales will be quite enlightening, may be few will also want to do corner balancing BBQ sounds even better of course

Base of operations: The hill top covered area on top of the paddock over looking Hog Pen

I'll be in touch, thanks.

[DVC]

Just stumbled upon this thread, and I have enjoyed reading through all the informative (and encouraging) M3/4 feedback! I'm rocking a lowly 335i on the NJMP tracks up in NJ, but I'm already looking forward to the the next car in a few years...likely an M2, but still haven't ruled out a few other options, including the M3.
The KW HAS system sounds interesting... I was wondering, is it recommended to re-corner balance after each adjustment to the ride height?