About

Hello and welcome to Automotive Thinker!

I created this site so that I could share my thoughts with anyone who thinks like me; that is, thinks about cars and automotive technology all of the time. With this site, I hope to add upon and to expand my thinking in anything car related and I hope to do the same for you. I will mostly be writing about topics that concern high performance and racing, but not just limited to that. I will share my experiences, but am also very happy to scrutinize anything that’s suggested so don’t hesitate to contact me.

I hope that you will enjoy my site and we can learn from each other. Don’t be a stranger, and happy thinking!

About Me: John Milmont

Even though I hold a degree in business from Northern Illinois University, I have been passionate about cars and racing for longer than I can remember and have always tried to be as well read as I could on the subject. I have been club racing on and off for around 15 years with various clubs around the Chicago area; and like any grass roots racer, I have always done my own work and fabrication. I am educated and have experience on virtually every machine found in a typical machine shop. I have setup, trouble shot, and programmed CNC equipment, worked in fiber reinforced plastics, and can also lay down a good weld on anything that’s weldable. I have also had the honor of being on my university’s Formula SAE team when it ran its most successful year in 2007, finishing 19th out of 100+ schools worldwide.

These days, other than my day job, I find myself tinkering on a race car that my brother and I share. The car, now amazingly considered a classic, is a 1989 Pontiac Firebird Formula 350. The car is fully caged a set up for road course duty. The car always seems to be in a constant state of development and I struggle to think of anything on the car that’s from the factory other than the paint.

Contacting Me:

If you would like to contact me directly, simply add a comment to this page and I will reply via email. Your comment will not be displayed publicly unless I have already approved a previous comment you made somewhere else on the site. Your email is not shared or displayed publicly. You can also contact me on Twitter.

14 Comments to "About"

  1. Rodney Cibura's Gravatar Rodney Cibura
    March 1, 2017 - 9:59 pm | Permalink

    Hi, I have a BMW 135i. I came across this website because of the 50/50 weight distribution article. I track my car frequently and have made a number of modifications, big front brakes, semi slicks, coil overs, front sway bar, some hp increase etc. I’m considering weight loss options where I can probably achieve 40 – 80kg additional weight loss at reasonable cost. The problem is the majority of this weight loss is from the rear. A 10kg weight bar BMW places in the rear bumper and a lightweight battery , rear seat removal. If you are faced with a.decision of less total weight and forward weight bias, or more equal weight bias and more total mass, would you always opt for less total mass and try and compensate the weight bias with tyre and suspension adjustment? Thanks.

  2. gabriel espiritu's Gravatar gabriel espiritu
    April 13, 2017 - 1:42 am | Permalink

    hi man i appreciate your article here about the carbon fiber repair can you email me for more detailed instruction i really need help please reply asap

  3. Mark Lupher's Gravatar Mark Lupher
    October 7, 2017 - 2:13 pm | Permalink

    Hi John. I love the articles and I’m taking the rear bias weight distribution to heart (and somewhat to the extreme), and have a related question for you. I’m rebuilding a Volvo P1800 as an electric autocross car. Of necessity most of the batteries and therefore weight will be behind the driver. I am trying to keep it as low as possible, but I am running into a dilemma, some of the batteries (Tesla packs) will need to either be placed above the rear axle and higher than I would like, or behind the rear axle but low and even with the differential. So my weight question is this: What would give better handling characteristics, a cg that is higher but more centered or a cg that was lower but more rearward?

  4. Gordon Forbes's Gravatar Gordon Forbes
    March 14, 2018 - 1:18 am | Permalink

    Stumbled onto your site and voraciously read everything! Some of the best explanations of complex topics in simple language that I’ve seen anywhere! If I may be so bold as to ask for your thoughts on a couple of esoteric items regarding fwd. I race a 1996 Honda Prelude on an asphalt 3/8 th mile oval (mild banking) in a Mini Stock class. “Rotation, rotation, where art thou rotation?” Fighting terminal understeer and getting some oversteer is an interesting suspension tuning challenge. At the moment the car has an open differential. I have done all the usual tricks: increased spring rates, poly bushings, Koni shocks with race valving, larger ARB front and rear, higher roll stiffness in rear, preloaded front ARB, stickier tires in front and old hard tires in the rear (no stagger allowed), using a pyrometer to set tire pressure and camber adjustments, widened front track width via wheel offset, lowered the car and used roll center adjusters, corner weighting with reverse crossweight, relocated mass (battery, fuel cell) low and left, set rear toe for rear steer, caster split at the front, etc.
    I almost find it more fun to play Crew Chief and test various changes more than the actual racing.
    Having done the above I’m down to a few ideas which I cannot find answers for. The wider track has of course moved the scrub radius from OEM slightly negative to very positive. This has numerous evil consequences but the reduced load transfer durring cornering by far outweighs the negatives. While I cannot run tire diameter stagger I was wondering if in addition to caster split what would be the effect of having the front wheels with different offsets so that one front tire had more/less scrub radius than the other? I read that changing scrub radius changed toe upon acceleration but the article only addressed rwd and I didn’t know how applicable this would be to fwd; in that I am trying to reduce understeer upon corner exit and also attempt to apply power earlier while still turning. If such a “scrub split” as described would help in any way would the front left want more or less scrub radius than the front right? Would the reduction of front track width with one wheel having more offset outweigh any advantage to such a scrub split or is it better to just get as wide a track width as rules allow?
    Would having a lot of Ackerman accomplish this also? I’ve read that “excessive” Ackerman slows the car down due to increased inside wheel slip angle but that was once again referencing rwd. In fwd I would think that I would prefer having the front left tire pull the car to the inside with more Ackerman than geometrically required (unless this would increase the slip angle so much that the tire lost traction and slid). Your thoughts?
    Finally, I’ve read that having the left side of the car lowered more than the right would not be beneficial, however this seems counterintuative. Wouldn’t having the car “pre tilted” into the left turn help, as in load transfer body roll could bring the car to level instead of the body roll inducing camber gain on the outside wheels as the suspension went into compression . A softer spring (or less ARB) could then be used which would help tire compliance with the track.
    Sorry for the long message. I just love this stuff but some things aren’t addressed by Smith, Puhn et all and Miliken is far beyond my ability to understand.
    Thanks in advance for your consideration.
    -Gordon

  5. Don's Gravatar Don
    March 30, 2018 - 5:45 pm | Permalink

    John, I am building a off road vehicle that could be used for daily driving all from scratch. I am having second thoughts about my brake system using solid rotors and wanted to ask your opinion on it.

  6. April 23, 2018 - 7:24 am | Permalink

    John, I have a 1969 Volvo P1800. It has coil springs all around. Rear wheel drive. This car needs noticeably less steering input to keep it in a straight line when it has a full tank of gas in it, about 70lbs. I think the front end geometry is changing slightly, perhaps toe in or camber with the full tank. What front end settings would change the most with the added weight of a full tank of gas? Rich B.

  7. Ben's Gravatar Ben
    July 18, 2019 - 11:57 pm | Permalink

    Hi John,

    I came across your site because of a link a friend sent me to do with progressive rate springs. He has a BMW M2 and the stock suspension was rather good – but now with KW progressive rate springs and stock shocks, it rides horribly and easily hits the bump stops! He’s going to go back to stock…

    I also read with interest your article on 50/50 weight distribution because I too thought that having a perfect 50/50 was the best for handling and lap times. I’m glad that it isn’t, because both of my cars don’t have anywhere near this, but I am interested in improving both of them for fast twisty road driving, and possibly the occasional track use.

    The two cars I have are a 2018 Audi RS3 sedan which is totally stock (for now!) and a 2009 Audi S5 V8 coupe in manual that has been supercharged with an APR Stage 3 kit. It also has some supporting mods such as Milltek downpipes and catback, clutch, etc.

    The main problem I seem to be having with both cars is excessive, uneven tyre wear when I push them too hard. The second problem is more with the RS3 – it just feels like it wants to push wide, whereas the S5, seemingly less so – so the RS3 feels less enjoyable to drive than the S5 does. So I have a series of questions for you – it would be awesome if you could provide some answers if you can!

    Firstly, the RS3 – as it comes with an inbuilt G-force meter, I have tried to identify how many G’s I can do before excessive tyre wear (on both inside and out, but more on the outer edge) starts. It seems to be about 0.7 to 0.8 G and I cannot get it to do anymore than 1.0 G before it starts understeering, which is on the stock Pirellia P Zero tyres. I have a friend with a 718 GTS who has done 1.63G on street tyres! The outer edge of my tyres (mostly the fronts) can be chewed up quite badly after just a few minutes of driving at 0.7 G and above which I think is quite unacceptable. The inside edges also wear quite badly but not as bad as the outer edges. It almost looks like the tread has melted together and just worn away!

    The car also runs a tyre pressure monitor and I believe the recommended pressure is about 38 psi. I run usually about 35 psi in the winter so that when I am having a fang, tyre pressures increase to about 38 psi – if I am pushing very hard, perhaps 39-40 psi.

    The car also has adjustable suspension but this tyre wear problem seems to occur no matter which setting I use!

    Interestingly, it runs 255/30R19 tyres front and 235/35R19 rear (with 9.0″ and 8.5″ width wheels respectively) – Audi’s reason for this was to try and reduce understeer (normally it runs 235’s all round but the front 255’s are part of a Performance Package).

    1. How do I get it to stop chewing out tyres, especially the fronts? (Other than driving slower of course!)

    2. How can I get it to handle neutrally, perhaps with a little oversteer?

    3. What are your tyre recommendations? As in, widths and sizes? I have access to a set of TTRS 19 x 9.0J wheels which I am planning on running all-round with 255 tyres all-round. Due to the finicky Haldex AWD system, it will complain when a non-square setup (other than the custom OEM tyres) is used because of the slightly different rolling diameter (the OEM tyres have identical rolling diameters). I don’t really like the P Zeros and the only other way I can see to avoid the Haldex complaining is to go with a 255 square setup – my favourite tyres right now are Michelin PS4S. Also, a square setup will allow me to rotate my tyres!

    Now for the S5: as previously mentioned, this feels fairly light to drive, and has less understeer than the RS3. I can trail brake fairly heavily into a corner and it doesn’t understeer much at all. About the only time it really understeers is under heavy acceleration exiting a sharp corner. It has a lot of mechanical grip and I am running 275/30R20 all round with Michelin PS4S. When I do this, it chews out the outer 2″ of both front and rear tyres – they go a bit “furry” (whereas in the RS3 they just look like they’ve melted!) – and the inside edge seems to be OK. I am unsure if my car has the optional Audi Sports Diff (a rear LSD) – it probably is running the stock open rear diff – but cannot feel any tyres scrabbling for traction, even with WOT out of a hairpin in 2nd gear!

    As far as I know, it is running the stock suspension all round (I bought the car 2nd hand) and am quite happy with the ride. The handling is quite nice too, so my question for this car is more around the excessive outer edge tyre wear. The suspension seems fairly well controlled – and it never bottoms out, so I think if I could keep the stock shocks and springs and make adjustments elsewhere, this would be preferred. However, I can definitely be persuaded otherwise if you can provide reasons why I should upgrade it!

    The main thing with both cars is that both are road cars. The S5 is the weekender while the RS3 is the daily. While I may take either to the track, this is probably unlikely, but I do take them out of long drives with various car groups in twisty backroads so they must ride well and have plenty of clearance too. The S5 probably sits at a “good looking” height (maybe a 10mm drop would be ideal) whereas the RS3 looks like it could do with a 10-20mm drop.

    Any help and guidance, or pointers to good references, would be much appreciated! If you have any specific products or kits you know of that are suitable for either of my cars, please let me know. I am totally new to the aftermarket suspension area so am unsure what to look for in kits, or whether to go for a semi-custom setup, or what sorts of testing to do, etc!

    Thanks again,

    Ben

  8. Ben's Gravatar Ben
    July 19, 2019 - 12:02 am | Permalink

    Hi again John,

    I just wrote to you about my RS3 and S5.

    I put the incorrect wheel specs for the stock RS3 wheels and the TTRS wheels I am planning to use.

    The correct wheel specs for the stock RS3 wheels are:
    Front: 19 x 8.5J ET46
    Rear: 19 x 8.0J ET42

    The TTRS wheels are 19 x 8.5J ET43 all round.

    Regards,

    Ben

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