MirageJHU

Hi,

I searched, and read quite a few threads on this topic, but none of them truly answered a question that's been burning me up...

Currently on my 93 R1 I've got Koni Yellows with Ground Controls and Racing Beat Front and Rear way bars with FTL mounts and M2 trailing arms.

I was never happy with the roll of the car through corners, I've got pictures at the end of the post.

From the threads I've read, this is what I've come up with:

TriPoint Adjustable front sway bar (already ordered)
Mazdaspeed rear sway bar (planning on ordering)
and I'm thinking about coil overs with a spring rate of 11kg mm F and 9 kg mm R as I believe that's what Howard Coleman is running.

I'm just looking for suggestions, especially for that rear sway bar or other spring rates. If the spring rates seem low, this car is 50% track days and 50% spirited weekend driving, I don't want to crack my teeth or **** blood when I get out, but I can handle a tough ride...I'm young and stupid

Thanks for reading and any input you guys have!

Now for the pics:

2MCHPWR

iTrader: (2)

what size tires do you run and are they R comp's?
beautiful pics.
why not revalve the konis' and get slightly stiffer springs?
your set up should be good?

Mahjik

iTrader: (1)

A similar thread:
https://www.rx7club.com/suspension-wheels-tires-brakes-20/tein-mono-flex-other-options-716404/

MirageJHU

Thanks for the compliments

Running A048s 265/18 up front, 285 in the back

I read about revalving, but that's the other part of my question, to your guys' expert eyes does it look like I need stiffer springs/shocks or anti roll bars and stuff?

The main concern I have is really rear end traction, especially in super awesome off-camber turns for example turn 2 at Infineon...you think stiffer springs with revalved Konis and staying with the RB front and rear sways is good?

for those that don't Infineon, as you cross start finish there's a flat out up hill left hander that's turn one, turn 2 is a right hander that's basically like cresting the hill you were just climbing...I actually have a series of shots of me spinning the FD there in the wet, camera man's lucky day...

Mahjik, thanks for the link, definitely read that thread and got some ideas for coils but I was wondering about ideas for the body roll. I don't know that much about suspension and my thoughts were than this side to side motion is better controlled by anti roll bars, please correct me if I'm wrong?

I was wondering if people familiar with or people that have this set up have suggestions for anti roll bars, or maybe they can tell me it's time to step up and either revalve like 2mchpwr suggested or get new super expensive coil overs

Thanks guys

Silver7

Body roll is not a bad thing as long as your suspension is not bottoming out. I've always been told that you should use springs just stiff enough to keep your shocks off of the bump stops.

I've used a stiff rear sway bar in the past but have since swapped back to the stock rear sway bar. I was getting too much oversteer with the stiff rear sway bar. It alway felt like I was driving on ice. Since I went back to the stock sway bar the rear feels more planted. My spring rates are 500/400 lbin.

MirageJHU

Hey Silver7,

Interesting that you went from a stiff rear bar to the stock one!

My (probably misguided) take on body roll is that it needs to be severely minimized. What I've got pictured doesn't actually bottom the shocks into the bump stops (the tires hit the fender lining before that ) but I think something to keep both rear tires planted a little better could be more stable and thus more confidence inspring?

If that's a totally wrong and misguided theory, then I need to learn proper theory I suppose, any good links

TRISPEEDFD3S

iTrader: (26)

Get a bigger spoiler and you might get planted more in the rear...

Mahjik

iTrader: (1)

Mirage,

Sometimes some lean is good. It really depends on the complete setup. Obviously if you look at the professional GT sports cars in races like ALMS, those cars barely sway. However, they also have some HUGE rubber as well as many thousands of dollars in suspension setup.

Having said that, if I were you, I would mirror the setup of some of the more elder track guys here on the forum like Howard Coleman, Crispy, Maxcooper and the others. A lot of these guys just don't pick parts and run them, they do a lot of testing and data logging to see what's helping and what isn't. Without that kind of testing, you are just basically shooting in the dark at a setup. So for something like this, following the leader can save you some money.

Springs of 11kg mm F and 9 kg mm R would be a good setup. However, I would also have the Koni's rebuilt for it.

KhanArtisT

iTrader: (2)

Good god thats a pretty car!

gracer7-rx7

iTrader: (16)

What level are you running HPDE and which organization?
Are you able to tell us what the car is doing in a corner?
Is it understeering, neutral, some oversteer?
At what point in the corner are you experiencing this?

It sounds like you are fixating over what you see in photos. Worry about the handling. Some body roll isn't bad.

MirageJHU

Mahjik,

That was very helpful, I really appreciate that. You and 2MCHPWR seem to be in agreement so I'm going to start looking for a shop that can do that and I guess finding those matching springs. I'm also going to search and read more of Howard and co's posts to figure out everything they have

GRacer7 - I run with a few different groups in NorCal, I mostly focus on getting out to tracks I like (Sears&Laguna hehe)

The car's roll makes me nervous through the corner and I was looking for ways to minimize that to gain more confidence. I've experimented carefully with getting on the throttle earlier even if it's just barely dipping in (following the "string theory") and the car quickly decides to step out (power-oversteer I suppose...)

While working the sensitive throttle application is definitely very high on my list of skills to work on I'd also like to make the car more friendly to that...I'm not sure I'm articulating that sentiment correctly though.

I included the pictures to try to show that, instead of describe it haha maybe that's my other problem.

KhanArtisT thanks for the compliments man

Howard Coleman

iTrader: (6)

my compliments on getting your FD out on the type of track for which it was designed... and it is on a road course, properly set up, where it takes a back seat to no car.

further, my compliments to all of the above posters who have provided valuable help.

a final comment before getting into the meat and potatoes... Mountain View? that's really disgusting as i sit 21 miles from one of the world's greatest road courses (Road America) which is currently under a foot of snow.

o k.

at what tire pressure do start your session? all 4 corners of the car.

what tire pressure do you have at the end of the session. all 4.

do you use a pyrometer and if so what's the data?

what are your suspension settings?

what is your ride height at the fender lips?

what are your corner weights?

what brake setup do you have?

what is your spring rate?

shock rebound setting?

you probably don't have answers to all of the above but please fill in as many as possible and we can get started making your car both faster and easier to drive.

howard coleman

MirageJHU

Howard!

What's wrong with Mountain View I'm about 2 hours from both Laguna and Sears Point. Littler further for Thunderhill, even further for Reno-Fernley although I do have to express my utmost jealousy, Road America is world class and I hope to drive it one day!

To your questions I start a session with 24-25 and end with 28-29 all the way around. I can't remember exactly, I remember that I was playing with the pressures to try to get even wear across the tread, I have these written down in my notebook which is currently in the car, in Mountain View, while I'm in NJ for a few more days

I don't even know what a pyrometer is so the answer would be no to that one

I'll measure the ride height, it's very low though. Suspension settings I'm honestly not sure what it means, I have Koni Yellows and Ground Control springs. I have to check the receipts that came with the car to determine what rates are on the GCs. The shocks, if I recall correctly have three settings and I have it..in the middle

Brakes I have AP/M2 racing big brakes up front and stock rears.

Corner weights, I asked a shop for this measurement and they refused to give it to me saying it wouldn't be accurate because I don't have true coil overs? I didn't argue with him but I haven't gone back to that shop. Was he lying to me?

Looking forward to hearing your thoughts!

-Annand

MirageJHU

A good friend of mine sent me a great picture of turn 2 for those not familiar with it

Silver7

It will take some pretty stiff spring rates to eliminate your body roll. If you do go with higher spring rates then you will have to get your konis revalved for optimum performance. Even then you will find that the Konis, by design, are really inadequate during high speed supension movements.

The general consensus on spring rates for track driven FDs is somewhere in the 500 to 650 lb/in front springs and 300 to 450 lb/in rear springs. You can experiment with different sway bars but then you may begin to experience other problems such as oversteer. I have an eibach front sway bar and stock rear. When I used the eibach rear sway bar, I had less body roll but less grip in the rear.

I have 500/400 lb/in springs and feel the car handles pretty well on the track. I am looking to go higher just to keep the wheels from rubbing my fender. The only problem is I am limited due to my shocks (GAB Super R).

Howard Coleman

iTrader: (6)

nice picture of you pulling away after lapping the blue vette...

since you are away from your car we will just put a number of items aside until you can supply them. i will monitor the thread and await further info.

just a couple of points for you.

starting w the most basic point. the fd is a front engined rear drive car. as such, the primary challenge of making it go faster on a road course is ALWAYS hooking up the rear end. think of road racing as a series of drag races.

imagine two cars that can run exactly equal quarter mile times but one gets a second head start.

hooking up the back end is all about getting the jump on the clock or the car you are racing against. you can't push on the right pedal until you have traction in the corner.

the rear end needs all the help it can get. it supports more than half of the car's weight under acceleration AND, unlike the front, propels the car. so the rear tires do 2 things yet have the same frictional abilities as the front that just steer the car out of the corner and are greatly un-weighted.

that's why you are running 285s in the rear and 265s in the front. that's why you run a lower spring rate in the rear for more grip. that''s why you SHOULD run a lower (3 psi minimum) air pressure in the rear. that's why you should engineer your car for more rear weight... i have 54% rear weight on my dual purpose street//track FD.

all to be able to push on the right pedal sooner.

if you run the same air pressure front and rear w everything else set up correctly your car will oversteer. air pressure is VERY important. the NEXTEL cup guys adjust their tires to the quarter pound.

tires should be thought of as part of the suspension-spring rate. more air equals higher spring rate. less air= softer lower spring rate.

before you buy anything further you need to start at square one.

actually you do need to buy an inexpensive probe type pyrometer (around $1-200 and indespensible) and an accurate easy to use tire pressure gauge.


align as follows:

first set ride height at 25 inches at the top of the wheel wells
1.2 degrees negative camber front
1.2 degrees negative camber rear
front anything between a 1/16th and an 1/8th inch toe-in
rear zero toe
zero rear thrust angle.
equal modest caster

do not listen to anyone at the alignment shop. give them the above specs and tell them to do it. further, tell them you want a print out of the before and after settings. BTW, the FD is EASY to align... so don't let them hand you a huge bill.

set tires at 30 front, 27 rear cold

set rear shocks full soft
set front shocks middle

run 5 hard laps. pit the car. immediately get tire temperatures w your pyrometer and tire pressures. record each. make adjustments before going back out.

the above, IMO, is the minimum that anyone that tracks their car should do. if you do it and make the right adjustments your car will be lots faster and easier to drive.

it is important to run a proper spring rate. springs are more important than shocks. (this does NOT mean that shocks are un-important). you can generally adjust shocks so they are in the ballpark. (I had a shock dyno for a number of years so i KNOW shocks).

if your spring rate is wrong there is little you can do but go slow and burn up tires and maybe hit the Armco.

a couple of points about springs....

a 600 pound per inch spring is 600 pounds for the first inch and 1200 pounds for the second inch and 1800 pounds for the third inch. the corner of your car weighs around 700 pounds.

stiff is not fast. a car w springs that are so stiff there is NO suspension movement at all will laterally transfer the EXACT same weight as a car w springs that allow a normal 2 degree body roll. the fact that your car isn't rolling therefore doesn't effect your cornering capability...

unless

the suspension doesn't offer negative camber gain on bump. the FD was designed as a true racecar as far as suspension geometry so some body roll is compensated for by camber gain. notice the first picture of your car for example. the one from the rear. notice the Left Rear tire.... looking great camber wise yet the body is in roll. that's an example of Mazda's race suspension at work.

stiff springs DO however cause major problems. while they don't effect the amount of lateral weight transfer (BTW, you want NO transfer... that's why lowering the car is FAST) they do SPEED UP the transfer. guess what, the faster the weight transfers the HARDER it is to keep the car from the wall.

a car w the proper spring rate will tell you just what it is going to do and you will look like Mario and enjoy the ride.

so we need to find out what springs you have... i run 8 front (about 450 pounds) and 6 rear 378. i consider 10 (566) fr and 8 (422) rear to be max for aggressive street and running hard on the track.

i recommend the TriPoint Speedway Engineering front swaybar (.188 wall) and the Racing Beat rear bar.

you are absolutely fine w Ground Control shock collars and the Konis set properly as long as you run the right spring rate w your GC collars.

run the stock upper shock mounts. do not run the "pillow ball" upper mount. it is a lose-lose. the upper mount is an insulator between the chassis and the spring. it absorbs all kind of NVH. win. further, the upper mount has NOTHING to do w the geometry so you gain nothing performance wise and you lose comfort.

as far as corner weights... skip all that. just set the car up square at 25 inches and the weights will be what they are which will be fine. if you want to go faster you can start moving things rearward. the battery being the first item. what you want is more rear weight.

i also really appreciate the manual steering on my FD. power steering has no place on such a car and you gain road feel... i ditched my PS in 99.

that's it for now. the above mods will not only take a whole lot of seconds off your lap times but will make the car a breeze to drive at the limit.

please get back to me on your spring rates etc...

here's my favorite mazda running under the lap record at Road America winning the June Sprints ...



more details... https://www.rx7club.com/old-school-other-rotary-63/my-rx3sp-gt3-scca-614456/

good luck,

hc

gracer7-rx7

iTrader: (16)

one thing to add to howard's comments on alignment, make sure you are sitting in the car when they align it.

when i sat in my car for an alignment, camber changed by .3 on the driver's side and around .2 for passenger side.

I am usually able to find a good alignment shop by going to the regional sections of bimmerforums.com or miata.net. Lots of racers and autoxers on those boards.

Silver7

Howard - those are some very good suggestions, especially for someone just getting started in tracking.

I used to think that my spring rates were about as stiff as anyone would ever want to drive on the street until I drove a 900/700 lb/in with JRZ shocks. This suspension setup was was more enjoyable to drive on the street than my 500/400 in/lb setup with Konis or Gab Super Rs. Eventually I would like to run this type of setup. To me its the best of both worlds, shocks that can tame an aggressive spring and enough spring rate to keep the wheels off the fenders during hard cornering. You also have the ability to lower the car to your desired height as opposed to being limited to 25".

If you look back 8 or so years ago there were a few track FDs (Jim Obrien, Brad Barber) that ran some pretty aggressive spring rates in the 1000/800 range. Maybe someone with more knowledge on their old setups could chime in with more specific details.

2MCHPWR

iTrader: (2)

yeah i agree.
my JRZ's with 900/650 ride nicer than my mazdaspeed 400/300 progressive rates. More controlled movements and not jarring. Haven't raced on them yet as they were just put in during the off-season. where in PA are you? send to PM i guess

eoph

Is 1.2 degrees of negative camber all you would run on r comps? I was reading how people are saying I would be crazy not to run 2.0+ degrees of negative camber.

tjZ06

Well, actually it's the opposite. This picture follows the one above, same lap, just heading into turn 6:



Anyway, I'm not a typical DUMBestic guy here to bash on RX7s. I have the duty of driving Mirage's FD while he's back east to keep her going. And it is always a pleasure. I had a good friend w/ a LS1->FD that I used to co-drive and the FD chassis/steering certainly is a great platform.

There's also some great info in your posts Howard that I can apply to my own setup. Time to invest in a pyrometer aye Mirage!?!

-TJ

PS- just for fun, a few cars both Mirage & I passed plenty during the day:

2MCHPWR

iTrader: (2)

PM me if you want a ride in my LS1 FD with JRZ's as long as it ain't snowing.

primerGrey

iTrader: (13)

If you are in Mountain View, finding a good alignment shop is easy - take the car to Custom Alignment. They have a reputation for being the best in the area, although perhaps a bit expensive.

OC_

body roll IS a bad thing. This is why: Load Transfer!

If you have a lot of body roll, the weight gets transfered to the outside tires which eventually become overloaded and slide. By limiting body roll, you distribute the load better across all tires.

But, If you put really stiff springs on, your car will not transfer the weight to the rear when accelerating. So it will be hard to lay down the power when coming out of a corner. thats why its important to look at the system as a whole: springs, rollbars and shocks!

Silver7

Body roll is not bad, all cars have some and need some. Excessive body roll is. The small amount of body roll in the pics looks normal to me. I would not condider it excessive or severe enough to cause his car to handle poorly.