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-   -   Autocross: Can a fb compete with Miatas? (https://www.rx7club.com/race-car-tech-103/autocross-can-fb-compete-miatas-863055/)

Kentetsu 09-21-09 05:31 AM

Nice work! Vipers are fun to watch trying to autocross; if they only had a little
more horsepower they might do alright. lol. Like trying to swat a fly with a sledge
hammer. :)

Bruceman 09-22-09 11:02 AM

Thought this may warm the hearts of all FB autocrossers: See the CSP results
http://detroit-scca.org/e107/e107_fi...s_9-20-09a.pdf

Jim Susko gave the CSP guys in the Detroit Region a lesson in his IT-7 FB. Sounded awesome too. All were using Hoosiers except #26. The 99 Miata in second was a Spec Miata race car. I was so excited to meet Jim and see his car in person. But really Jim is an excellent driver while no one else in his class has close to his ability. Vance Johnson, who was second, and I were always very close in times when I autocrossed my FB a few years back. I'm just average in driving ability so just saying its all about the driver.
I regularly pound the ES Miatas but not when they are driven by a good driver.

If you don't know who Jim Susko is, see here: http://www.gforceengineering.net/

mazda6guy 09-22-09 06:52 PM

Sweet deal! Thanks for the motivation Bruceman.

Kentetsu 09-23-09 08:12 AM

Wow, I didn't know that Susko actually raced a 7 anymore. Very cool, wish I could have been there. :) You get any pics of his car?

mustanghammer 09-24-09 12:00 AM

Check out the back of the Solo II rule book. I think Susko is in there a few times in DSP - a Fiat X19.

The double adjustable Koni's that we use are race strut inserts that require 2" strut tubes. You have to shorten the stock tubes and then chuck the spindle in a lathe. The negative with the double adjustable Konis is that one of adjustments is on the bottom of the strut so you have to pull the insert out to access that adjuster.

I have been thinking about the FB vs Miata issue for the last few weeks. I had a chance to look at the fast Miatas at the 2008 Solo II Nationals. They were impressive and certainly very well driven. I don't think their speed was from horse power but rather I think the key was the tires they were running. The Miatas have the the ability to fit and use 13x10 wheels fitted with 255/40 x 13" tires. Putting a lot of rubber on the ground and being able to use it is what makes a car fast in a Solo II.

When I was running in CP the big revolution in the class was the movement from small diameter (21 - 23") slicks on 10" wide wheels to taller (25"- 27") slicks on 12" wide wheels. Once the guys got enough suspension under their cars to use the bigger tires they could add more HP and the cars handled better. The result was that the CP cars went faster...allot faster. They also got allot more expensive but that is another issue.

There are more examples of the affects of big tires in Solo II in the Stock classes. Again, when I was active I didn't get beat by too many stock class cars at Solo II Nationals. At one point I am pretty sure I finished in the top 5 in SS and beat all other Stock Classes based on time comparisons.....of course I was still 2-3 places out of the trophies in CP. Now, when you look at the results you see how incredibly fast allot of the stock cars are when compared to Street Prep and Prepared class cars. The difference is the size of the tires being fitted on cars from the factory and the fact that they have suspensions that can use the bigger tires.

The biggest advantage that the Miata has it that it has a really good suspension. Put one on a lift....they are really cool cars. This means that putting on big tires and making them work is very possible with the Miata. The FB, on the other hand is not quite as blessed. It has a pretty good Mac Strut front end (compared to the crap under a mustang) but the stock rear suspension is a problem. A tri link helps but I think that you would also need to get creative with a set of traction bars that sort of replace the lower control arms and are in the correct geometry. This can be done but it is a grey area.

So my final assesment is that for an FB to be competitive it will need to run as much rubber as the Miatas to use their HP advantage. Then you need to get springs, sway bars, dampers and traction aids to use the big tires. It would also help if one of the two course layouts you are asked to run allows an RX7 to get up to speed and not slow down too much. So, yes, an expertly driven, properly prepared FB runing fresh monster Hoosiers on the right course can win a National Championship.

Kentetsu 09-24-09 10:36 AM

I currently have a set of Diamond Racing wheels that are 13x8. I am considering selling those off and moving up to 13x9 wheels, which would allow me to run the new monster Hoosiers (255/40/13).

I'm still not convinced that I will need to install my trilink/panhard setup (the car handles so damn good as it is right now), but that is another option that I am considering.

I'm figuring that, although the National level Miatas will be very highly prepped, I think that the supercharged Miata I'm currently battling most of the time (which is very well prepared and driven) would at least hold its own against them. If that is an accurate statement (potentially, anyway), then I should be in pretty good shape. Last race I beat one of the two drivers of that car, and the race before that I beat both of them. And don't forget, that's with them on Hoosiers and me on Sumitomos. This is the only real "guage" that I've got to go by right now, and I think it's a pretty realistic one.

My car might not be completely prepared for hitting the Nationals, and I'm probably not ready as a driver yet. But I think that both of those factors are getting close enough to being ready that I should start considering the possibility. Hell, if I get my arse handed to me when I start running the regionals, then I guess I'll know my answer sooner rather than later. :)

mustanghammer 09-24-09 12:06 PM


Originally Posted by Kentetsu (Post 9517824)
I currently have a set of Diamond Racing wheels that are 13x8. I am considering selling those off and moving up to 13x9 wheels, which would allow me to run the new monster Hoosiers (255/40/13).

I'm still not convinced that I will need to install my trilink/panhard setup (the car handles so damn good as it is right now), but that is another option that I am considering.

I'm figuring that, although the National level Miatas will be very highly prepped, I think that the supercharged Miata I'm currently battling most of the time (which is very well prepared and driven) would at least hold its own against them. If that is an accurate statement (potentially, anyway), then I should be in pretty good shape. Last race I beat one of the two drivers of that car, and the race before that I beat both of them. And don't forget, that's with them on Hoosiers and me on Sumitomos. This is the only real "guage" that I've got to go by right now, and I think it's a pretty realistic one.

My car might not be completely prepared for hitting the Nationals, and I'm probably not ready as a driver yet. But I think that both of those factors are getting close enough to being ready that I should start considering the possibility. Hell, if I get my arse handed to me when I start running the regionals, then I guess I'll know my answer sooner rather than later. :)

Going to Nationals is something that you really should experience. It is very different than a local or even a Divisional level event. The driving on display in all classes is truly amazing. The courses are big, tricky and usually have some design elements that you have never seen before. The surface itself is probably completely different than what you are used to.

Whether or not you are ready or have the ability to compete is something you cannot know until you have been there. Everyone has to have a first time. Wondering or speculating about where you might place isn't what you should be thinking about. You go for the experience and the learning opportunity. To be honest with you, unless you are comparing yourself to drivers that go to Nationals and have run on the new site you have no way to know how well you will do. But again....that should not be your concern or focus.

What I mean by learning opportunity is that you will have the ability to look over all of the car in your class during impound. Despite the fact that most of them will be Miatas and Hondas you can learn an incredible amount by just looking, listening and asking questions. There will be other classes you can look at too that you can learn from as well. It is like going to Autox University!

Also you can meet with tire reps and maybe even some shock reps and find out what they have to offer. By the way, if you are buying new tires before National you can usually buy them at the event site and save yourself tax and shipping charges. I bought a set of Kumhos that way and saved a little cash.

My write up is what I believe a max effort FB will have to have to win. Your results may differ....but you will not know unless you go!

Unevolved 09-24-09 01:35 PM


Originally Posted by mustanghammer (Post 9517178)
Check out the back of the Solo II rule book. I think Susko is in there a few times in DSP - a Fiat X19.

The double adjustable Koni's that we use are race strut inserts that require 2" strut tubes. You have to shorten the stock tubes and then chuck the spindle in a lathe. The negative with the double adjustable Konis is that one of adjustments is on the bottom of the strut so you have to pull the insert out to access that adjuster.

Any further information you could give me on this setup would be much appreciated. That sounds like something I want to try, I think it'd be worth it, and it sounds within my capabilities.

jdmsuper7 09-24-09 04:47 PM

Even if you can't do nationals next year, try to run Peru or Toledo. You'll get a real good feel for how you running on a national level at those events.

mustanghammer 09-25-09 12:36 AM


Originally Posted by Unevolved (Post 9518214)
Any further information you could give me on this setup would be much appreciated. That sounds like something I want to try, I think it'd be worth it, and it sounds within my capabilities.

Here is how we do it at Santa Fe Garage.

1. Starting with a strut from a 84/85 FB (they have bigger/stronger spindles) all but about 5" of the strut tube is cut off.

2. The strut is then chucked into a lathe using what is left of the strut tube. This allows the bore of the strut tube that runs through the spindle to bored out from the bottom.

3. The strut tube bore is opened up so that the new 2" strut tube is a tight but not a tolerance fit with a depth of about 4" or so.

4. Once bottom bore is done, the strut is removed from the lathe chuck and the rest of the old tube is cut off.

5. The the spindle is put back in the lathe - this time it is chucked using the bore that was cut in the bottom of the strut tube.

6. The remaining strut tube bore is opened up to fit the new 2" strut tube.

7. When the strut tube bore is finished the spindle is placed on a mill and the spindle to streering arm bolt bosses are spot faced so that a lock nut can be used on the bolts that attach the spindle to the steering arm.

8. A bottom cap is machined on the lathe - the strut tube has to have a bottom. Santa Fe Garage cuts a tapper into the bottom cap to help center the strut cartridge and a hole is put in the center for adjuster clearance

9. A Spring Perch is machined to fit the stut tube

10. The new strut tube is inserted into the bored out spindle and tig welded into place.

11. The Spring Perch is tig welded into place on the strut tube

12. The bottom cap is tig welded into the into the bottom of new strut tube.

If a geometry correction spacer is going to be used on the bottom of the strut, we mig or tig weld them to the bottom of the spindle as well.

I beleive that Susko sells these on an exchange basis. We source the strut tubes and Koni Strut inserts from www.kcraceware.com. The tubes come in various lengths and need to be matched to the length of the strut insert you are planning on using You can contact Santa Fe Garage at www.santafegarage.com

Kentetsu 09-25-09 10:59 AM

Great info Scott! I saw this shock setup on the Gforce website, but at $1,300 bucks I'd have to sell one of my kids in order to afford it. :) Didn't much like the fact that you have to pull the insert to make one of the adjustements either.

mustanghammer 09-25-09 08:56 PM


Originally Posted by Kentetsu (Post 9520249)
Great info Scott! I saw this shock setup on the Gforce website, but at $1,300 bucks I'd have to sell one of my kids in order to afford it. :) Didn't much like the fact that you have to pull the insert to make one of the adjustements either.

Wow....he gets $1300! Good thing we can make our own. Actually once you get the rebound adjustment set your good to go so pulling the insert doesn't happen all that often.

Unevolved 09-26-09 08:57 PM


Originally Posted by mustanghammer (Post 9519601)
Here is how we do it at Santa Fe Garage.

1. Starting with a strut from a 84/85 FB (they have bigger/stronger spindles) all but about 5" of the strut tube is cut off.

2. The strut is then chucked into a lathe using what is left of the strut tube. This allows the bore of the strut tube that runs through the spindle to bored out from the bottom.

3. The strut tube bore is opened up so that the new 2" strut tube is a tight but not a tolerance fit with a depth of about 4" or so.

4. Once bottom bore is done, the strut is removed from the lathe chuck and the rest of the old tube is cut off.

5. The the spindle is put back in the lathe - this time it is chucked using the bore that was cut in the bottom of the strut tube.

6. The remaining strut tube bore is opened up to fit the new 2" strut tube.

7. When the strut tube bore is finished the spindle is placed on a mill and the spindle to streering arm bolt bosses are spot faced so that a lock nut can be used on the bolts that attach the spindle to the steering arm.

8. A bottom cap is machined on the lathe - the strut tube has to have a bottom. Santa Fe Garage cuts a tapper into the bottom cap to help center the strut cartridge and a hole is put in the center for adjuster clearance

9. A Spring Perch is machined to fit the stut tube

10. The new strut tube is inserted into the bored out spindle and tig welded into place.

11. The Spring Perch is tig welded into place on the strut tube

12. The bottom cap is tig welded into the into the bottom of new strut tube.

If a geometry correction spacer is going to be used on the bottom of the strut, we mig or tig weld them to the bottom of the spindle as well.

I beleive that Susko sells these on an exchange basis. We source the strut tubes and Koni Strut inserts from www.kcraceware.com. The tubes come in various lengths and need to be matched to the length of the strut insert you are planning on using You can contact Santa Fe Garage at www.santafegarage.com

That's good to know, I'll have to look into that. Excuse my noobish question, but is there a specific damper length I'd need? And I'm guessing there's no major fitment problems with double-adjustable dampers in the rear (at least not to the same extent), but which rear dampers are used?

And one thing I can't grasp from your instructions is how the damper is held into the knuckle when it's all said and done. It seems like, from how I understand it, that under full droop the whole assembly would come apart.

Sorry for being a little slow with this, I work better with diagrams. :)

mustanghammer 09-27-09 10:15 PM


Originally Posted by Unevolved (Post 9523017)
That's good to know, I'll have to look into that. Excuse my noobish question, but is there a specific damper length I'd need? And I'm guessing there's no major fitment problems with double-adjustable dampers in the rear (at least not to the same extent), but which rear dampers are used?

And one thing I can't grasp from your instructions is how the damper is held into the knuckle when it's all said and done. It seems like, from how I understand it, that under full droop the whole assembly would come apart.

Sorry for being a little slow with this, I work better with diagrams. :)

The Koni inserts we are running come in several lengths. The tubes do as well or they can be shortened. Yes they do need to matched up. Contact Charlie at www.kcraceware.com for specifics. The Santa Fe Garage cars use shorter inserts - shorter than stock - so that we do not need to raise the strut mount to avoid bottoming. If I get by the shop I'll pull a part number off of a spare insert that I have.

The finished product bolts into place the same way that the stock part does. The only difference is that the strut tube is a bigger diameter so that you can run strut inserts with larger diameter pistons. These struts will dampen higher spring rates than anything that is available to fit the stock diameter strut tube. That is the whole reason for this mod. If you don't plan on running really stiff springs on the front....like over 450lbs then a set of Illuminas will work fine.

The strut insert is held in the strut tube with a cap that threads into the 2" strut tube - just like the stocker.

Sorry, no diagrams, photos, etc at this time.

The cheapest double adjustable rear shock is a Koni Sport made for a Fox Mustang. They basically bolt in and have adjuster at the bottom for rebound and one at the top for compression. This is what KC Raceware and Santa Fe Garage use on the backs of there E Production cars. Charlie at KC Raceware gets them for us....contact him.

diyman25 10-01-09 04:04 AM

3 Attachment(s)
well i am not race in autocross any more. but the the race track i race now is a lot like autocross...


i think one big point of autocross is Tire !!!!. who can fit widest and newest tires have more chance of getting better result.. this is down size of SA if you are runing GSL-SE brake you cant
fit 13 inch wheel. and using 15 inch wheel require a lot of work to fit 255 hoosier into it ;)



here are some video and picture to cheer you up a bit.

https://www.rx7club.com/attachment.p...1&d=1254387253

As some guys might know. i have a 1981 MAZDA RX-7. That i nick name it to HSF (stand for Honda

S2000 Fighter. At recenly locoal Time attack event. I was award to Fastest Street Tires car of that day.... :)

I was .3 sec faster then sec place car. which is S2000 :) Feeling pretty good for a 30 years old car to get such result

some thing i have change when i ship HSF to ASIA. a 4.7 Final drive. and 195/50/15 Toyo R1R. way too narrow for my HSF. but that is also one of more reasonable tire to get here

http://www.youtube.com/watch?v=3b51QXY5C1k

I am consider to buy a 3 link set here from usa. cause as you seen in video. most of turn i am going side way. a lot of reason is my power. poor suspension from mazda and also ha some of turn in this track is Bank.......which made it pretty hard to drive in my opion

Kentetsu 10-06-09 10:25 AM

I still drool over your car man. :) Great videos too. Nice to see these cars out there humiliating the Miatas and S2000s....

Keeble 10-19-09 12:53 AM

well, i don't know if it was driver skill or what but i killed a r33 skyline on saturday by 2 seconds.

also i'm running single adjustable koni yellows in the front, drop in fit, also have the part number 8641-1072-SPORT

have fun

Kentetsu 10-21-09 12:53 PM

Good info on the shocks. I'm happy with my Illuminas right now, but maybe down the road when they wear out I'll have to look at the benefits of an upgrade.

And nice kill on the Skyline dude! Those things are monsters. I got to play with one at the Tail of the Dragon meet last spring and had a great time... :)

j9fd3s 10-21-09 02:06 PM


Originally Posted by Kentetsu (Post 9575847)
Good info on the shocks. I'm happy with my Illuminas right now, but maybe down the road when they wear out I'll have to look at the benefits of an upgrade.

And nice kill on the Skyline dude! Those things are monsters. I got to play with one at the Tail of the Dragon meet last spring and had a great time... :)

yeah if i had to do mine again, i would have bought bilsteins, they are about $10 more than the tokiko's. we also have the ability to valve em here..

kwerks 10-21-09 08:37 PM


Originally Posted by Bruceman (Post 9512948)
Thought this may warm the hearts of all FB autocrossers: See the CSP results
http://detroit-scca.org/e107/e107_fi...s_9-20-09a.pdf

Jim Susko gave the CSP guys in the Detroit Region a lesson in his IT-7 FB. Sounded awesome too. All were using Hoosiers except #26. The 99 Miata in second was a Spec Miata race car. I was so excited to meet Jim and see his car in person. But really Jim is an excellent driver while no one else in his class has close to his ability. Vance Johnson, who was second, and I were always very close in times when I autocrossed my FB a few years back. I'm just average in driving ability so just saying its all about the driver.
I regularly pound the ES Miatas but not when they are driven by a good driver.

If you don't know who Jim Susko is, see here: http://www.gforceengineering.net/

Jim Susko is a very talented man! He gave me help with my old Fiat x1/9! Talk about driving skill and knowledge! If I track up north I have to give him a call to check out the FD I have prepped.

orion84gsl 10-21-09 09:35 PM

I think your selling yourself short, Kentetsu.

I've seen him drive quite a few times and it's almost scary (the night run at the Dragon comes to mind) how good he is at making that little car of his do what he wants it to. Especially on the Sumi's. While a good tire for the price, they are still an economical summer street tire. Far from a race tire. They are actually pretty decent in light snow with full tread too. With race tires you'd be shaving seconds off your times, and nailing FTD every time. Once Sterling works out a solution for the stock manifolds you'll have even more power than you need.

I would suggest you make a serious effort to get to the next nationals. Hell since I'm missing DGRR10 I'd even make the trek out to see you compete. You'll never know just how good the car is until you take it there. There you'll have a chance to really evaluate the car and find out if you need the panhard/tri-link or not. For serious competition I think a harness and racing seat would help a lot. I noticed in my videos that even with the belt tight I seem to get tossed around quite a bit, which is why I hold the shifter so much. Some gloves too, for those hot humid days when your hands get a little slippery.

While there is always some improvements to be made (even F1 drivers screw up) I'd find it hard to believe anyone else could just hop in your car and know it's limits any better than you.

Kentetsu 10-23-09 12:24 PM

Cut it out Chris, you're making me blush! :) Get yer darned car back on the road already!!!

Hyper4mance2k 10-23-09 05:07 PM

You can compete with a miata, but it takes some work. I autoX in sports prep. I finished 2nd in points theis season and all season I was chasing this guy in his spec miata. 108whp on toyo r888's. It took me learning my car and kumho710's to finally beat him on the final race of the season. I'm finally getting pretty fast in my car, and I think there's still a ton of speed in the car that I havent been able to get out of it yet.
https://www.rx7club.com/nw-rx-7-forum-33/wow-adrian-hot-today-track-868116/
My car:
190whp
S313B w/ 12A Y center iron. cleaned up ports.
Custom RE,ISC, HP42K exhaust. Weber 48IDA, Crane HI6R DF ignition w/ FC coil. Hi6 on trailing, Mazdatrix camber plates, REspeed coilovers 300/200 springs, Tokico mr2 struts in front, kyb gas-a-just rear, stock front swaybar, no rear swaybar. hawk HP+ pads, custom master cylender brace, FC radiator, front mount oil cooler,


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