swilson@assetworks.com

iTrader: (13)

Howard,
I was catching up on the thread and saw your post using milk crates in place of a set of purpose built ramps.

I just went back and re-read the post and I saw that you use a 4X4 internal wooden brace inside the milk crates. I think that it is important to note that for safety this is a critical addition.

I used milk crates for years when working on my motorcycles to support them with both wheels off the ground. One day I had one collapse (broke into pieces) and drop a 500 lb Harley in my garage while I was at work. Maybe this is due to the sun and heat of south Texas or just the age of the particular crate that caused it to collapse. As I said I had been doing this for years without incident.

silentblu

iTrader: (1)

If you look i think he has a support system on the inside, pretty much an I-beam using a 4x4 block i believe

gracer7-rx7

iTrader: (16)

Howard,

I've always been curious about the difference in spring rates front to rear and how one should go about deciding on a how much of a difference there should be. Is there some kind of formula that you use for that or is it just testing on track to see what rate works with the rest of the setup?

I also wonder about the staggered tire size and its affect on selection of spring rates. I see that you are running 255 front and 295 rear with your spring rates of 432 Front and 378 Rear. This difference in front/rear tire width should give you more rear grip all else being equal - which would make me wonder how balanced that rate differential would feel if one was running the same size tire front and rear. Many of the earlier coil over kits from M2 and Ground Control had a 100 lb difference between front and rear rates.

Reading Speed Secrets, the author says to first find a rear spring rate so that you have good grip coming out of a corner and then to find a front spring rate. Sounds like a lot of trial and error (and expense) in that approach.

As I understand it, after spring selection you can fine tune ultimate handling behavior using sway bars but that does assume that the springs are already providing the desired handling traits.

Thanks.

Howard Coleman

iTrader: (6)

swilson.... thanks for your comments re the milk cartons. i will throw a quick edit in the post so as not to maim too many people.

spring rate, bar rate.

springs are all about tire/road contact. springs also effect roll.

it is a major mistake to size springs to control roll as the point is reached (quickly) where tire/track contact is lost. /think no grip/

bars should be used to control roll. you are looking for no more than 1.5 inches of shock travel. (use a tie wrap on the shock rod... see earlier post). bars should provide approx 40% of total corner rate.

since the FD is a rear drive car the rear suspension gets the bias for grip. the rear holds up half the car AND drives the car forward. we need all the rear stick we can get. ultimately, going fast is all about finding as much rear grip as possible. (so i agree w Speed Secrets)

how much? as much as you can get but it will depend a bit on your hp, weight distribution, the track etc. rear grip is job one... that's why i run 9.5 wheels up front and 10.5 rear along w larger rear rubber.

lots can be done by fine tuning tire pressures and camber too.

hc

Eggie

With that said, Howard, do you have any tips for people running the same size tires F&R? My track setup is the "Sleeper fitment" (Manny, not Woody Allen...) with 255/40-17 all around.

aoc007

iTrader: (5)

Hey, first off let me say great thread! I always enjoy reading your posts Howard. I have a trackday coming up on Sunday at Buttonwillow and would like some advice on tuning my new setup.

Some background...

Koni Yellows set to lowest perch (10mm front, 15mm rear lowering) and firmest rebound dampening.
H&R Sport springs (1.25" f&r lowering, unknown rate)
total lowering is ~1.6"F ~1.9"R
Suspension Techniques f&r bars, 1.25" front solid bar non-adjust, .75" rear solid bar set to the softer of the two settings.
17x8 front 245/45, 17x9 rear 255/40 falken azenis rt-615 (recently replaced w/ no shaving)
Other misc suspension parts include, rx7.com trailing arms and toe links w/ heim joints, tiresmokin7s 18pc delrin lube groove bushings, mazdatrix endlinks, re-a sway mount, and all other suspension/shock rubbers&pillowballs replaced brand new.
drivetrain mods include, 9.5lb fly/act clutch, gotham engine brace, a-spec tranny and diff braces, reinforced ppf, rebuilt turboII diff w/4.33 and delrin diff mounts, but stock motormounts (no rebuild in sight !)
the motor is a rebuild with stock ports and sequential twins with full boltons at 330wheel before creep but I don't expect much at a hot trackday
brakes are RB BBK f&r w/ ET700 pads
the car is also obviously lighter than stock but I havn't been able to corner weigh it yet to checkout the balance
also for aero i have the series 8 bumper and adj. wing along with an re-a diffuser (if the latter even helps!)

And for me I have a couple trackdays and autox under my belt along with the scca school in a spec miata but I still think that the car is beyond my skill level and I definitely do not want to mess up the car I spent two years building, so I run 7/10ths and a less aggressive setup.

I had an alignment appointment scheduled for Friday anyway so I will try out your setting Howard and pickup a pyrometer along with some white paste for tirewear but 30/27 hot sounds about right and although I don't think my Azenis have super stiff walls I think they will suffice.

So my questions are...

1. Do the Konis have tame enough valving to run the rebound at full hard? (Buttonwillow has a fairly smooth surface)

2. I wanted the car as low as possible but is lowering it more in the rear than the front detrimental?

3. Do you guys think the rear bar is still too large and will create some oversteer?

4. This track doesn't have a lot of really high speed corners but I think the magic mountain area is fast enough to warrant some downforce (~90mph at one apex), I've read that cranking the series 8 wing to full creates some front lift (probably too technical for my purposes but Crispy says that at 14.5deg the Cl is 0.053F, -0.075R) So should the full setting be good?

5. If BBS will ever forge them I have 18x9F and 18x10R RG-R's coming that I plan to wrap in those new Nitto R-comps, are 18s advisable on the track or will there not be enough sidewall squish to give me grip coming out of a corner? Also should I just go with whatever sizes Nitto recommends for the 9 and 10 inch wide wheels?

6. And what do you guys think, should I disable racelogic traction control and maybe even pull my ABS relay?

Any other advice from the experienced guys is appreciated! I just want to get out to the track and haul some *** safely now that my baby is pretty much complete!

Thanks
-Andy

Howard Coleman

iTrader: (6)

brakes are RB BBK f&r w/ ET700 pads/////////// good move on your brake system. the ET700s are a nice pad but please understand they are not a 10/10ths pad. you cannot run flat out w this pad and not expect some brake fade. it is my opinion that you need race pads if you are going to the track. so leave a bit on the table as to braking/////////////

the car is also obviously lighter than stock but I havn't been able to corner weigh it yet to checkout the balance//////// not a big deal. it is what it is and mazda has done a fabulous job getting rear weight in the car. try to remove weight and relocate weight to the rear, lower and to the pass side./////

also for aero i have the series 8 bumper///higher drag than the stock 93-95//// and adj. wing along////flat it out for your initial outing/////

And for me I have a couple trackdays and autox under my belt along with the scca school//// good for you... the real deal///// in a spec miata but I still think that the car is beyond my skill level and I definitely do not want to mess up the car I spent two years building, so I run 7/10ths and a less aggressive setup.//// good approach//////

I had an alignment appointment scheduled for Friday anyway so I will try out your setting Howard and pickup a pyrometer////// good, essential. be sure to record your temps and pressures and post them here///// along with some white paste for tirewear but 30/27 hot sounds about right and although I don't think my Azenis have super stiff walls I think they will suffice.//// tie wrap your shock rods and measure them//////////

So my questions are...

1. Do the Konis have tame enough valving to run the rebound at full hard? (Buttonwillow has a fairly smooth surface)

/////others may chime in on this as i don't know the rate of the H R springs. if the car talks to you in advance of doing things in the corner they are fine. if the car is twitchy and hard to control softem the shock setting////////

2. I wanted the car as low as possible but is lowering it more in the rear than the front detrimental?///////// when we talk ride height here we measure the distance from the track to the top of the wheel well. please gives us this dimension. your rear tires are .65 less diameter than your fronts BTW.//////////

3. Do you guys think the rear bar is still too large and will create some oversteer?
///////since we currently don't know your spring rate it would be a guess. stock 93 bar is 17.3 but wall thickness is unknown. there are lots of ways to get longitudinal balance at the track such as tire pressure/////////

4. This track doesn't have a lot of really high speed corners but I think the magic mountain area is fast enough to warrant some downforce (~90mph at one apex), I've read that cranking the series 8 wing to full creates some front lift (probably too technical for my purposes but Crispy says that at 14.5deg the Cl is 0.053F, -0.075R) So should the full setting be good?////////// since this is early in your FD track learning curve i suggest you run the wing at normal street setting. you want to get a neutral base w tire temps and pressures. please post them after your outing. messing w the wing will obscure learning about the basics of what you have.///////

5. If BBS will ever forge them I have 18x9F and 18x10R RG-R's coming that I plan to wrap in those new Nitto R-comps, are 18s advisable on the track or will there not be enough sidewall squish to give me grip coming out of a corner? Also should I just go with whatever sizes Nitto recommends for the 9 and 10 inch wide wheels?////////// 18 or 17 are fine. you should look for a contact patch approx the size of the wheel width. i run 9.5 and 10.5 w 255 fr and 295 r////////

6. And what do you guys think, should I disable racelogic traction control and maybe even pull my ABS relay?////////i would not run the racelogic. you want to be the one controlling the car and it is just another thing to distract you. i like the unit for drag racing not road racing.. i would not disable the abs. you should learn braking control and not get into it. that said i removed my abs as i never got into it and i needed the space.//////

Any other advice from the experienced guys is appreciated! I just want to get out to the track and haul some ***//////////// good for you. i am impressed that you did an SCCA school. good stuff. be sure and share your readings w us. don't forget to work w tire pressures. they should be different for each corner of the car.////

good luck and let us hear from you,

hc

gracer7-rx7

iTrader: (16)

aoc007
Hey Andy. It sounds like our setups are very similar.

Power = street port, seq 99 twins, full bolt on supporting mods; putting down 310rwhp at 10 PSI.
Brakes = full RacingBrake kit running ET500 and Hawk HT10
Suspension = Konis with H&R springs and Eibach front and rear sway bars, rear bar set at the inward setting, Rotary Extreme trailing arms and toe links, Poly diff bushings, Poly front lower control arm bushings.
17” x 9” rims with 255/40 Kumho MX all around.

I’ve run Buttonwillow a few times. Great fun track!

Regarding your questions:

I’d suggest running the Konis with the front perches at the highest setting up front and middle perch in the rear. That gives you an even ride height front to rear at around 25.25” – 25.5”. At the lowest setting you are probably ľ” lower than that. On hard track use, the tires may rub the fender liners when using the lowest perch. With this setup my car corner balanced well. Details here: https://www.rx7club.com/showpost.php...&postcount=100

The car was VERY driveable with this setup. I could drive the car 10/10ths on some corners once I got more comfy with the car and track. The tires were great too. Very progressive and very good communication with decent grip.

Q1. Do the Konis have tame enough valving to run the rebound at full hard? (Buttonwillow has a fairly smooth surface)
A1: Yes Konis have enough valving to run up to 500 or 550 lb/in springs. They work very well with the H&Rs. I generally run them full stiff up front and half a turn from full stiff rear on track.

Q2. I wanted the car as low as possible but is lowering it more in the rear than the front detrimental?
A2: Read Howard’s comments about suspension travel. With the Konis at the lowest perch, I don’t think you’ll have enough travel for the shocks to do their job. Being too low at either side is detrimental. The H&Rs might not have a high enough spring rate to keep your tires off the liners at such a low ride height.

Q3. Do you guys think the rear bar is still too large and will create some oversteer?
A3: I think the rear bar will be fine. On my car, with the suspension mods listed above, I get slight understeer at turn in that I balance with throttle through the apex. The car remains neutral with maybe very slight understeer throughout the corner and allows me to get on the throttle w/o wheel spin or other excitement. I drove this setup on a skid pad like environment and the car generally exhibited light understeer that could be managed with throttle. Years of racing karts and momentum cars have made me a pretty smooth driver so ymmv.

Q4. This track doesn't have a lot of really high speed corners but I think the magic mountain area is fast enough to warrant some downforce….
A4: Magic Mountain is pretty exciting. Sometimes I got that turn right and it was a wonderful feeling. IMO it is the only scary turn there. The car is very light cresting the hill and heading for the apex. Be smooth and cautious there until you get comfortable with it. Not sure if more wing will make a difference but try it at both extremes back to back to see if you notice anything. Small change might be harder to feel. I would agree with Howard’s comments on that.

6. And what do you guys think, should I disable racelogic traction control and maybe even pull my ABS relay?
A6: I don’t see why you’d need the traction control. Leave the ABS alone. The ABS computer controls brake bias on the stock brake system. Read the other post from someone else a page back.

With my Kumhos, I tend to start at 30 PSI. It seems to work fine but I never tested with a pyrometer. I’m running something close to the Pettit alignment specs.

As you get comfortable with Buttonwillow and your speed increases, you may fade the ET700s at the end of the main straight. I ran that track with the ET500s and as speed increased, they started fading at the end of the main straight so be aware. They were fine on the other parts of the track. The Hawk HT10s while offering amazing braking power were overkill for my setup running street tires at BW. Hawk Blacks might have been a better choice.

Its going to be hot at BW. Be sure that your radiator is well ducted with the gaps around it sealed off and keep an eye on your temps.

TitaniumCranium

iTrader: (3)

A few comments for those interested in autox, checking tire temps is not going to tell all that much due to the short run times, usually less than 80sec. with that being said you might be over compensating with too much negative camber in an attempt to get the inside tread hotter than the outside tread. What I look for on my tires how far I'm scrubbing down the side of the tire. Scrubbing the side means the tire is flexing rather than sliding, which heats up the core of the tire, not just the surface. Annother thing to check is how much pressure is gained once the tire has warmed up, I like to see 2-3 psi gain after a run.

I was running Kumho MX 225/50/16 (32psi F, 30psi R cold), speedyway front arb 1.25 x .188 wall (which helped a ton), Tokiko Illumna w, H&R sport springs, and stock rear arb. The car felt very comfortable/predictable on the street, but a bit too soft for autox.

My new setup that I will be running on Sunday is Victoracers 245/45/16, Koni 3012's bult by ProParts, and 700lb F, 500lb R Hypercoils with the same arb's. I will start with -2 F / -1.5 R camber , 1/16 out F / 0 R toe.

Howard Coleman

iTrader: (6)

think tire pressure is all about 50-50?

think again.

as i have often stated, tire pressure is your number one item for chassis tune at the track. tires are part of the chassis compliance and as such they should be thought of as an additional set of springs. lower tire pressure =s less spring rate=s more relative grip.

in a recent post i mentioned that, ultimately, you will end up running different cold tires pressures at each corner of the car....

take a look at NASCAR's min required tire pressures for this weekend's race:


Minimum Recommended Inflation:
Left Front -- 22 psi; Left Rear -- 20 psi;
Right Front -- 48 psi; Right Rear -- 44 psi

notice no similar pressure at any corner. obviously the 25 pound average difference between the right and left is because of the circular track.

HOWEVER if you think about a road course, most are clockwise, right hand turns win the day. that's why i carried 300 pounds of lead in my right side rocker panel... inside weight wins in road racing. there are very few left turns compared to right turns. the really sneaky courses (Mid-Ohio turn one) are built w important left turns to extract as much pain as possible but reality intercedes and the rights always win the day.

eventually once the tires grow to optimal pressure you want them even temperatures-wise but look where you have to start to get there! i say you want to have = pressures but it may simply not be possible... here is a Goodyear/NASCAR stipulation for hot pressures:


Technical Inspection Inflation:
Left Front -- 30 psi; Left Rear -- 30 psi;
Right Front -- 48 psi; Right Rear -- 45 psi

as you can see, even starting in the low 20s running on an oval 30 is about the best you can do for the unloaded side of the car..

on another subject there are a bunch of people running this weekend. i know Steve Kan is out. Steve and i spoke last week and i hope to get his temps and pressures to analyze for the thread. anyone else out please feel free to share your data

howard coleman

j9fd3s

iTrader: (3)

i'll second that! we've been running a spec e30, tuned with a pyrometer.

hot the inflation pressures are within 1-2psi, cold they are as much as 5psi different, depending on the track

we asked the tire guy, and he told us the optimum temp range for the tire we run, and tune the chassis/pressures to get that.

we're running the toyo r888, which the drivers like.

Howard Coleman

iTrader: (6)

"optimum temp range for the tire"

absolutely. every tire has an optimum temp and you need to eventually end up there through a combo of static weight, srpings, bars and suspension settings.

so you start out w dissimilar pressures at each corner and hope to end up equal hot.

hc

pluto

Hey Howard,
I took my car out this past weekend and ended up corded my front outer tires. These hoosier tires only have 3 track events (400miles?) My new PFC01 brake pads worked great and very linear. I didn't have any problems pushing the car this time around. Both my oil and coolant temp was awesome at 102F day. 208F coolant and 200F oil temp. It is pretty obvious that I needed more negative camber on the front since I can see more wear from middle to outside of the tire than the inside. What are your thoughts on the Avon slicks? I just ordered some to try out. I'm planning to change my front neg camber from -1.5 to -3 and back from -1 to -1.5. I also checked my spring rate today. They are 800# F and 600# R. You think the front is too stiff? Here're some pictures of my car at the track. One of the picture shows that my front wheel came off the ground while taking a corner.


http://www.hart-photography.com/phot...ewImage=477480

http://www.hart-photography.com/phot...ewImage=477474

http://www.hart-photography.com/phot...ewImage=477465

http://www.hart-photography.com/phot...ewImage=477456

http://www.hart-photography.com/phot...ewImage=477346

Howard Coleman

iTrader: (6)

real interesting pics. thanks for sharing.

as you know in a corner when you get on the gas the weight shifts 180 degrees from where it was under braking. when the longitudinal weight transfers to the rear and the car is turning the outside rear carries max load.

so on the gas in the right turn you are in the max force is on the outside (left) rear. the car rolls the left rear squats. 800 pounds of total lateral weight transfer at work.

the chassis is like a teeter totter. outside rear down, inside front up. so you tend to either lift or unweight the inside front wheel as you accelerate out of a corner.
you cannot lift an inside front if you don't squat the outside rear. they pivot on a line between the outside front and the inside rear.

if you look at the porsche gt3 in the following picture you will see even more inside wheel atmospherics.

http://www.hart-photography.com/photocart/index.php?
do=photocart&viewImage=477477

the reason the porsche pulls the wheel higher is that in order to deal w the nutty 911 variant weight distribution very soft springs are needed in the rear. soft rear springs, down goes the outside rear, up goes the inside front. big time.

since the FD has a really nice static weight distribution it runs front and rear spring rates closer together than the gt3. less front wheel air.

notice the porsche 944 w really good front to rear distribution (even a transaxle).
http://www.hart-photography.com/phot...ewImage=477357

to be clear you don't want the inside front unweighted. in order to get it back down you need to prop up the rear outside wheel. w the spring rate you are running i would highly recommend upping your bar rates.

as posted earlier in this thread next time you go to the track place a tiewrap on each of your shock rods and do 3 laps. you want to see no more than 1.4-1.5 inches of travel.

if you prop up your rear w more rear bar you will probably need to go up on the front bar so as to properly apportion the lateral 800 pounds of weight transfer.

how much front to rear depends....

you need to dial your camber in first.

your car clearly looks like it needs more camber in this pic:
http://www.hart-photography.com/phot...ewImage=477474

in addition the car is not accelerating (outside front rideheight down) and it should be in this part of the turn. i suspect it is not accelerating because it is still pushing due to the outside front camber being straight up...

you will need tire temps to do determine optimum camber. once you have the camber right so your inside tires are all 20 degrees (F) hotter than the outside and your pressures are correct then you can figure out the longitudinal trim and make the correct bar choices front and rear.

my camber settings posted in this thread are for aggressive street (-1.2) and i have consistantly stated that you take them to the track, do 3 laps, do temps and readjust the camber til you get what you need temps-wise so it appears you are in process. do find yourself a pyrometer and an accurate pressure guage, do the tire wraps and they will point you in the right direction.

knowing you i bet you were fast last weekend.

just wait til you try it on all four wheels.

regards,

howard

pluto

Hey Howard,
thanks for your advice. I'm replacing all my bushings with deliron bushings and heading to an alignment shop afterwards. My Avon slicks should be here next week. There's another event in August so I'll test it out and see how everything goes. Also, I don't run sway bar in the rear. Should I?

I was the 2nd or 3rd fastest guy out there. Most of the faster guys in the instructor and red group are running 1:28-1:33/lap. The white track mustang was running 1:25/lap. The GT3 RS was running around my time but he was on pirelli slicks. We were both running 1:22-1:23/lap. The other porsche cup race car was running 5secs faster than me (1:16-1:17/lap). I tried to keep up with him on corner but couldn't hold my place. I was running aprox 11psi because of the heat (320rwhp?). I usually get boost creep up to 15psi in colder temperature (370rwhp). Maybe I should get a boost controller to up my boost a little.

Either way, I'll provide more feedback next time around with my new setup.

Steve

Howard Coleman

iTrader: (6)

"I don't run sway bar in the rear. Should I?"

there is a sequence of items that lead to the answer.

determine proper camber.
determine proper air pressure at all four corners.
measure shock stroke w tie wraps.

you will then have the current balance and you can tailor the bars to work w that balance.

it is great to see you and your FD ontrack... just where the FD was designed to be.

hc

afgmoto1978

iTrader: (6)

FYI, Suspension Techiques does have a front bar. I have both and I really like them. The rear is set at the hardest setting on mine to balance out the front roll stiffness. I also have Tein Flex coilovers with 10kg/8kg springs for reference.



Info from Mazda Motorsports:

0000-04-7321-ST C S.T. FRT SWAY BAR 1 ALL RX-7 1993-95 $182.20

Front bar only, with bushings and mounting hardware. 32mm. #50175 Notes: 93-95 RX-7 (#50175)

0000-04-7331-ST C S.T. REAR SWAY BAR 1 ALL RX-7 1993-95 $173.25

Rear bar only, with bushings and mounting hardware. 19mm. Notes: 93-95 RX-7(#51165)

aoc007

iTrader: (5)

I recall you saying before that the rear bar on the hardest setting was too much and made the car oversteer?

afgmoto1978

iTrader: (6)

.....Your right, sorry for my unintended mis-information.....(running and hiding now)

gracer7-rx7

iTrader: (16)

That would depend on the rest of the suspension setup and front-to-rear tire sizes also. Stiffer rear springs with a stiffer rear sway bar generally = increased oversteer.

How was Buttonwillow?

Rookie84

I've recently picked up a set of Koni shocks, and am looking for springs to go with them. I was originally going to go with Illumina's but brand new Koni's popped up in classifieds at a great price, so I had to pull the trigger

Anyway, what would be your recommendation for springs? I was thinking Eibachs or RS-R Down (349/261) or Tein H-tech (391/291). From what I have read, Koni's seem to work well with higher rates so I am thinking about going with H-techs. What are your thoughts on this?

Thanks!

Howard Coleman

iTrader: (6)

i really am delighted to see everyone talking spring rates.

Rookie84, given you have over 300 ft pounds of torque from under 3000 rpm w your LS6 i would agree w your spring choice as the Teins would give you another 50 pounds of rate v the Eibachs and RS-Rs.

hc

Rookie84

Great. Thanks again, Howard.

aoc007

iTrader: (5)

Does anyone know the rate on the H&Rs?

Howard Coleman

iTrader: (6)

well, i just made my last call to H&R springs.

technician "Josh" assured me that there are "way too many factors envolved" to release their spring rates.

i asked him to just give me the rate at 1, 2 and 3 inches of compression and he said that H&R wouldn't do that.

if you'd like to talk further to Josh he can be reached at 1-888-827-8881.

i won't be running H&R springs anytime soon.

they might make great springs but they sure are lost marketingwise.

hc