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..... both of my off track excursions last year were because of the rear breaking loose. I've done all I can with the 27mm rear swaybar to get it a bit softer. So, as much as I hate to, I'll be trying a smaller diameter rear swaybar.

Next event - April 14th.

CR
A bit late, but did you consider making ~ 3/4" spacers for under the pivot bushing brackets, then extending the 27mm bar and adding a 2nd, softer hole, making the lever 3/4" longer? See more at your car prep thread, including RSB options and rates.

http://forum.mazda6club.com/dyno-track/247399-prepping-dedicated-track-car-42.html#post3519823

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Discussion Starter #42
As we wait for the 2014 autocross season to begin, we can reminisce about seasons past. Here is a younger CanyonRider early in his AutoX career - style and technique has not improved. :D



Next event - 2/2/14!
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Discussion Starter #43
The 2014 Season has officially begun! Chilly-cross at VMP yesterday! Actually it was a balmy 65deg. :thumbup: It was a ton of fun and the car was better than expected. I was bummed there were no other 6's out there (yeah, I'm talking to you slackers) :stickpoke:

I have some onboard video I'll need to edit and post for ya, but here are a few pics.

Can you spot the Mazda staged in grid?



Waiting my turn to kill some cones. :lol:



Damn, I need to get the back of that car lower!!

I wasn't sure what to expect from the car. Since the last event, I added coilovers on the front with 700lb/in springs, but still running Eibachs on the rear. I've gone back to the 27mm rear sway that caused so much oversteer previously. I found that the stiff springs on the front helped balance the stiffer sway on the rear - it was actually improved overall. Hopefully in the next few weeks I'll finish the adjustable rear perches and radius arms, and install my 500lb/in rear springs.

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Discussion Starter #44

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Did you keep the rear bar at the loosest (pre-slot) setting?

On the first video, is it possible you took too early an apex on the left turn cone, before snapping out the rear trying to get into the next gate at the correct angle?

No sign of understeer.

Based on my last run, roll rate front bias: (roll ctrs/CG were educated guesses)

spring --- 68%
bars ----- 57%
net ------- 62%

Does not look like it would be too much rear bias, but the roll centers and CG are just educated guesses, and you would need to give me better numbers to work with.

Your LSD front adds another variable.

Good for 1st test of new set-up

BTW: some of those firebird 400's were extremely fast street racing machines.

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Discussion Starter #46
I'm a bit behind schedule. The results and videos above were from the Feb 2nd event. At that point I had 700lb/in coilovers on the front and the fixed eibach springs on the rear. RSB was the 27mm set at full soft.

Since then, I swapped the rear cross member with adjustable perches and 500lb/in linear race springs; set the ride height and corner weights. The RSB remained the same - full soft.

Last weekend 3/15, I ran another AutoX in Wilmington, NC (sorry no video - technical issues). It was a short course, but we got 4 runs in the morning and another 6 runs in the afternoon. With the new setup and the RSB set at full soft, the car tended toward understeer - But you could induce a bit of rotation if you really jump out of the gas entering the corner. At low speeds, I just had to deal with the understeer. :mad:

During the lunch break, I adjusted the bar to full hard. Wow, what a difference. Rotation was much easier to induce and it was gradual and predictable - almost slow motion. I think I've finally figured out the right setup. I will run the RSB at full hard for AutoX. At the track, I'll start at full soft and tweek towards more firm in between sessions if it feels like it is pushing too much. :thumbup:

Next AutoX - 3/23 in Winston-Salem
Next Track event 4/5-6 at VIR

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Have you checked the ackerman effect, simple way is to go to full lock and pull in an imaginary parking space. IF toed in, you will see the front tire pulled in at the contact patch. That is what I found with my stock M6, set for minimal toe-in. On my race car, it had terrible ackerman toe-in, to the point you could not push the car at full lock. So I set it for lots of toe-out to start.

Between the lsd and a possible dynamic toe-in, if you cut the wheel too much too quickly at slow speed, understeer is almost impossible to dial out. Sebastian Loeb may be jerking on the e-brake.

One thing I noticed on the old video, was the low rpm comming out of some slow corners. I'm not sure the oem engine has that much low end torque. With the VVT,my car starts to pull at ~4000 rpm. I always tried to stay in as high a gear as possible when autox'ing my F-Prod'n car, but with a 3.89 rear (vs 3.23 stock GT6), never had to hit 1st.

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Discussion Starter #48
I've noticed the Ackerman effect is more pronounced since I lowered the car. I'm sure the tierods are not happy with the new geometry. This weekend I ran 1/8" toe out on each side and that seemed a little better at full lock. It's something I'll need to dig into further, but I suspect it's more of an issue during autoX than at the track. It's really tough to be smooth in AutoX when the turns are coming so close together. :eek:
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I here you about the turns ... I learned autox from Jerry Fink, a solo-2 expert.

2002 Laminar Concepts Viking SRX-7 - Sport Compact Car Magazine

With a few hints, I was able to take my class title in 2 of the 3 years I ran the local club. The most important thing was the pre-race walk around, putting an image of the course geometry to memory. I had to do it alone, to concentrate on car position, etc.

On the big track, I went frm the Triumph to a 924T and finally the Rx7 TT, each time gaining about 8 sec's. With that Rx7 + bolt-ons, those turns were comming up quick enough to match my limits.

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As I said in the previous post, the car was improved - it didn't snap oversteer like it used to, but clearly there is still plenty of throttle-lift oversteer as you can see in these clips:

https://www.youtube.com/watch?v=yMWgn3jTKDY

https://www.youtube.com/watch?v=g0krYl_G01U

Fun, but not fast. :lol:
So how do you stack up against the other FWD and RWD cars at the track? If it's not fast then are you at the back of the pack? It would be cool if you could provide pictures of a printout (if they give you one) of the cars that ran that day with their times as well as your own.
 

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Discussion Starter #51
So how do you stack up against the other FWD and RWD cars at the track? If it's not fast then are you at the back of the pack? It would be cool if you could provide pictures of a printout (if they give you one) of the cars that ran that day with their times as well as your own.
When I say its fun but not fast, I referring to sliding the car around the course. In AutoX, if you are sliding the car, you are losing time. The fastest time is at the limit of the car's grip - always under control. The quickest cars often don't look that fast while running the course.

Track and AutoX are very different and frankly, I kinda suck at AutoX. I feel I'm a better driver on Track. AutoX is a lot of fun and I use it for testing and tuning because of the low-key social environment and the events usually cost $25-$35. A weekend at the track is $400-$700 and your time is very busy, so you want your car ready to go and not spend a lot of time experimenting with various setups - minor tweek are OK, but not major changes.

The open track events I attend do not keep track of lap times or publish results. Its kind of a game that is played with the Track owners and the insurance companies - we promise we aren't "Racing" and the cost of the event is lower because of it. As a result, they can't do any timing and scoring - but I assure you most of us have telemetry equipment in our cars and are comparing lap times back in the pits. :p So to see how my car does on track, you can look at the in-car videos from VIR & CMP to get a sense of how often I'm passing vs getting passed. (link is in my sig) You can also get a sense of the other cars I'm (not) "Racing". :)

Attached are the published results of six AutoX events - My car is highlighted in yellow. These tables are raw times only and there are many classes - in fact I don't brag about winning my class because often I'm the only one in FP. :(

Take a look at the first table: Of 111 cars posting times from 36sec to 56sec, you'll find me 51st. About 3.75sec behind the fastest car. Note that the first 50 cars are less than 4sec apart, while the last 50 are spread over 16sec. Some of the cars below me: WRX, S2000, Boxster, VW GTI, 911, Cobra Mustang, MS Miata, MS3, Lotus Elise, Evo, M3, 350Z, etc. Are ALL these cars slower or less competitive that the 6? Hardly. I'd venture to say, with more seat time most of them could be within 4sec of the lead. AutoX is 90% driver. The guys in the top 20 could probably be there in just about any car.

CR
 

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As I understand it, Production class allows substantial engine modifications (cams, pistons, CR, induction) and you are basically stock engine?

This illustrates the cars you would compete against, if you were trying to be competitve:

https://www.facebook.com/pages/SCCA-Solo-F-Prepared-FP/247829511928433

For the big track, there may be a NASA class where you would be competitive, but for me the HPDE format was enough racing for me. If I could catch the guy in front of me, or drive away from the guy behind me ... those were wins. And if they were competitve cars, those were real wins. And I never had to risk side by side diving into corners with likely contact. I always had my times checked, so I was really racing against myself. After over 10 years of this and 1000's of track miles at the same track, I was asked to be an instructor ... based on seeing instructors stepping out of cars that had nosed a wall of rubber, rubbing the back of their necks, I quickly declined. That's not fun.


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Rear Sway Bar

A few days back, I had suggested a mod to the rear sway bar bracket, to allow the endlinks to be vertical at the stiff setting too. On the soft setting, it carries about 580 lbs on a 1G corner, if vertical. Alternately, you could get a 26mm Steeda front bar (vs RB 28.5mm) that reduces the total weight transfer front balance from 60% to 57%.

I assumed the length of the arms was 6", from at the pivots to the hole. When I made it stiff, I assumed 1.5" change in length, which changes the stiffness by a factor of 1.82 . The lever arm length change will increase the bar stiffness by the ratio or the lengths squared ... approximately. A more precise prediction is achieved by taking the ratio to the 2.1 power, vs 2.0 .

This made a change in total wt transfer front bias, going from 60% ( ~neutral) to about 53% !! The endlink load went from 580 lbs to 880 lbs if vertical, more if at an angle. Some of this will be reduced a bit due to the small motion ratio and deflection of the pivot bushings. I ran greased aluminum pivots on the GT6, to eliminate deflection at the polyurethane pivot bushings, and get more out of the bar.

For popular bar cases that I ran with oem springs, and accurate roll centers, the front Total Roll Stiffness biases:


------------OEM--------RB set -----RB rear

Fbar -----23mm ---- 28.5mm -----23mm
Rbar ---- 19mm ---- 27.0mm -----27mm
Roll ------ 4.66 ------ 2.29 ------- 3.16
Bias ------ 66% ------ 59% ------- 50%


The blue section was edited to correct a bad data entry in the spreadsheet.


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Discussion Starter #54
As I understand it, Production class allows substantial engine modifications (cams, pistons, CR, induction) and you are basically stock engine?

This illustrates the cars you would compete against, if you were trying to be competitve:

https://www.facebook.com/pages/SCCA-Solo-F-Prepared-FP/247829511928433

For the big track, there may be a NASA class where you would be competitive, but for me the HPDE format was enough racing for me. If I could catch the guy in front of me, or drive away from the guy behind me ... those were wins. And if they were competitve cars, those were real wins. And I never had to risk side by side diving into corners with likely contact. I always had my times checked, so I was really racing against myself. After over 10 years of this and 1000's of track miles at the same track, I was asked to be an instructor ... based on seeing instructors stepping out of cars that had nosed a wall of rubber, rubbing the back of their necks, I quickly declined. That's not fun.


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Yeah, the rules in FP are pretty wide open and my car is prepared no where near the limits of the rules. I probably won't spend much more money/time modifying the 6. I too am enjoying the HPDE format right now. I will continue to do HPDEs and AutoX with the 6 for a while. The next step for me (down the road) is building a Lemons/Chump car and team. I occasional crew/wrench for a couple different teams now and at some point I can see doing my own. But that's another big step in time and $ commitment. Not sure if the 6 is the right platform - we'll see.

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Lemons chumpcar looks appealing. With labor being free regarding the cheap budget, you would fit right in with your fabrication skills.

To run out the M6, you could add a built engine with optional larger displacement. For autox, it seems like 2nd is too low in rpms to pull out of sharp turns.



Some autox history

As I recall, first there was track time/time-trials for owners, allowed at some tracks around 1980's --- my GT6 days. Then lawyers shut it all down a few years, and track time was reserected as lawyer approved HPDE events (thanks to lawyers in their hot BMW's and Porsches).

The non-pro track times I ran at Summit Point with my GT6 included the track owner making ~even teams of 4 cars based on his recorded lap times. At the end of the day, two teams at a time would be lined up side by side in the staging lane. The lead cars were parked ahead 15 yards, angled for a LeMons start. So on GO, the 1st 2 guys ran to their cars, belted in, and took off down the last half of the main strait. Two big pylons were put on the track as stopping points where you jumped out and ran to the next team car and gave him a hand tag to take off. That was fun! and dangerous.


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It sounds like for a pure race car, frequency based selection of springs is not necessary, unless someone is winning in a similar but not the same size car, and he back calculates frequencies for you.

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Discussion Starter #57
VERY excited about running at MACS Cherry Point for the first time on Sunday. Miles of grippy concrete, fast course, reputed to be THE premier AutoX site on the east coast. Fingers crossed for good weather.

Next weekend - VIR!
 

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Discussion Starter #58
First Race - First Place

Awesome event and awesome site! Finished 1st in the combined Prepared/Modified Class. :thumbup:

Class Results

Raw Results 49th raw of 123 cars.

The car was VERY good. Really liking the new setup. I just need to get better at learning the course quickly. It always seems to take me 4 runs to figure it out. My last run was almost a second faster than my previous best and I felt there was still improvement to be made. It was nice to see a Speed6 out there - nice guy, nice car! He finished 8th in Novice class.
This weekend - Virginia International Raceway!! :seeya:
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Congrats!
For all the time & effort you've put in I bet it was great fun to reach a point where the work is paying off!
 

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Wow, you beat a fake lotus-7 modified, often an FTD go-cart.

Did you keep the rear bar at max stiff?

Did you add more toe out up front for the tight turns?

Any other changes from last run with lowered car?

BTW good idea to go with narrower tires for the HPDE event..

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