jatmon

can anyone on here recommend some good reading to help me learn more about race car suspension and race car handling? ebooks and online stuff is ok, but really prefer a real book. there seems to be quite a few out there, just wondering if there is anything in particular racers on here have found they liked and that will help me learn to better set up a car for road racing. thanks

Loki

iTrader: (1)

This is pretty good, it's a 10 part series, this is part 1:
https://motoiq.com/the-ultimate-guid...els-and-tires/

You can also check FatCat Motorsports videos on youtube where he covers a number of aspects with object examples. A bit more application than theory.

jatmon

thanks that looks helpful, hopefully i can get some of that to stick in my mind in a useful way

TeamRX8

iTrader: (25)

good grief, do people still fall for that guy? I thought that fad passed already.

https://optimumg.com/

jatmon

[QUOTE=TeamRX8;4942904]good grief, do people still fall for that guy? I thought that fad passed already.

would you mind explaining that?

bobtms

How much of a background do you have? I have plenty of recomms, but would rather match with your expectations.

bobtms

I sense you'll best benefit from just focusing on suspension setups... focusing on how to do the most with what you've got. For example:

Not the latest, but not so techie or complicated.

bobtms

Amazon hid the link, but that's Fred Puhn's how to make your car handle book

bobtms

Something a bit stiffer of a read is Carrol Smith's series of books.... "XXXXX to Win" like Tune To Win -- which is again, mostly focused on how to make use of what you've got, rather than re-engineer your car.

bobtms

If you're into cars, buy all of Carroll Smith's publications. Getting through these separates the weekend fun people from racers:

or maybe Adams' Chassis Engineering as well, which despite its name, has quite a bit of basic tuning stuff mixed into the theory.

jatmon

i have been racing lemons on and off since 2013 (mercedes c230) circle track before that. i recognize my lack of understanding of what is actually happening when we brake, turn in, accelerate out and so on. i believe i have a basic understanding, but i want to be sure that what i think i know isn't flawed or completely off, hence the need for more education. hoping that if we could get a better understanding of cornering and mechanical grip, i could start making better adjustments and less guesses. i will be checking out the mentioned books. thanks all

bobtms

Lemons? Great!

C230? That car's not $500!! LoL!

Suggest:

• Pick any of the books and read it. Touch nothing on the car.
• Buy a RaceLogic VBox Sport or equivalent -- $300 -- or borrow one and familiarize yourself with its use and reading data from it.
• Head to a HPDS event. Borrow a hot shoe driver, preferably in a RWD car in the C230's weight class (BMW guys?). Have them do 15-20 laps hot with the VBox on and collect their qualitative feedback on 1) what they'd change, 2) what can be done with driving styes to compensate, and 3) where on the track such modified driving styles (e.g. trail braking to cure understeer) simply don't work and are holding the car back. Ask about the car when it was "cold" (first 1-2 laps) and when it was "hot" (last 1/3 of run).
• Ask them to help you pick different tire pressures, make the changes (+/- 4psi tops) and send them back out for another 15-20 laps, VBox on. Take the same notes, questions. Repeat the air pressure exercise until the hot shoe says that's the best they think you can pretty much hope for with that setup.
• Look at your driver line-up and consider whether or not the feedback applies. If you're no where near their speed on the same course (say, within 1.5-2seconds per minute of the faster driver's laptime), then leave the car alone and work on matching their technique and suggestions. Chances are the car understeers pretty badly. This is relatively safe for less than good drivers, as the tendency in an accident is to brake and turn and that'll keep the car more or less on track and under control. If you're running a mixed driver quality team, have the car setup more or less for the slowest, as a good driver can "work" the car around the track while the worst driver is most likely to put the car into another or into a wall if the car is setup too loose or skiddish. Practice transferring weight using both gas and brake pedals. You'll become a better driver and stay safe in the process.
• If your vaguely close to their laptimes, then start working through the book you picked. The easiest in-general mods are pulling weight off the end that's sliding (e.g. front = understeer). It often costs nothing and you really won't go wrong since lighter is pretty much always better. Lemons is so loose for lightening mods that you can hack the car up and upset no one, so go for it.

I had a lot of fun renting a POS Camaro recently. It understeered terribly, but was otherwise pretty responsive, straight from the airport rental agency. In a weekend, I definitely up'ped my skills in right pedal management with that car and that was hugely gratifying and a skill I'll take with me wherever I go.

Too many people geek out on parts when the loosest nut was the one behind the wheel.

P.S.> Are you on the West Coast? Silver? Mixmaster?

jatmon

C230? That car's not $500!! LoL!

it is if you take it from a junkyard and use a ford 2300 from a pinto
we are currently putting together an rx8 for lemons that will be honda powered.
northern wisconsin

jatmon

hope its ok if i bring back this old thread. we ran our 24 hour race at high plains and did pretty well for a new car that has never been run.
did a lot of reading of some of the above mentioned books, i feel that they were very helpful getting me to understand a little better whats going on, especially with the tires. getting ready to start reworking the suspension, replacing the old rusted arms with new ones etc. i see a lot of the available aftermarket arms out there have adjusters built into them, which is great, but my next questions are what do we adjust it to? the front is pretty straight forward, but in the rear with all of the links going every which way i dont know where to set it. what i mean is, i could get the alignment to a factory setting in a static position, but what should be my goals as the suspension moves through its travel? for example, where do i want the rear toe to be in a hard corner with say 2.5 inches of compression in the outside suspension?

DocWalt

That's definitely more complicated.

You can measure the bump steer in the rear and figure out from other folk's shared alignments and ride heights where they end up under load.



I don't have enough front camber, but otherwise I'm happy with my alignment. 13" center of hub to fender, 800/600 spring rates. I'd be fairly disturbed if I saw 2.5" of compression on the outside suspension, even with my old spring rates of 672/448

Loki

iTrader: (1)

I'd leave the rear arms well alone. Adjustability is great as long as you can change one thing at a time and test, but there isn't really anything to be gained by messing with the rear. It does everything you need it to in spades already. Lots of adjustments will likely result in making it worse. Focus on the front.

jatmon

i hear you, most of this is hypothetical and me trying to better understand. in a race situation under heavy cornering and braking, what kind of suspension travel is expected if everything is working properly?

Loki

iTrader: (1)

Suspension travel is going to be a function of spring rate. Stock suspension is around 160lbs/inch of compression (+progressive bumpstop) whereas a race setup will be 500-600 for the rears. If you're taking a 1g turn in a 3000lbs car you can calculate the forces and get your compression. But this is all a little bit beside the point, your goal should be what behavior you want the car to have in that turn. If you want it to rotate/oversteer, see if you can toe out under compression (don't really recommend this), if you want stability, go for toe in. Since the rear wheels are driven the toe will also affect how it reacts to throttle application in the turn. Mazda figured all this out for the RX8/MX-5 rear multilink, that's why I caution against messing with it. Part of what makes these cars successful is how predictable and tame they are to drive at the limit, and messing with the multilink articulation messes with that.

But every suspension problem ideally starts with what you want the car to do that it's not doing right now, and then changing the fewest elements to get there.

jatmon

thanks much, that mostly answers my question. pretty sure if i could figure out how to ask a better question it would make more sense to me, but we are getting there

spectre6000

Not disagreeing with you necessarily, but the FCs were set up to toe out under compression from the factory. As were late 911s (actual 911s, not Carreras/"911s"), which is supposedly where Mazda got the idea for the FC. Made for some really fun low speed shenanigans if you ask me. I remember one corner that I could really load up the suspension at just 20-25mph or so, and really feel the rotation. Definitely something to tackle only if you really know what you're doing though.