flatlander937's Mazda2 build - SCCA STF / NASA NXF

[flatlander937]

Operation motor mount went fine. The old bushings weren't LOOSE, but I wanted to at least rule out them causing stupid amounts of wheel hop at the last event. I noticed the engine/trans feeling like they were shifting around a bit, most noticeable when accelerating and then letting off then getting back on it again in first gear. It wasn't anything like the stock Jello mount, but was bugging me.

The old bushings didn't have physical play in them, but you could spin the inner sleeve inside the bushings easily by hand... the new bushings you cannot do that again.

We'll see how it works out tomorrow

 

[flatlander937]

I've been slow to update my thread here since this forum is so slow but here goes:

From 4/24 Tidewater Sports Car Club PE#2:

NCCAR is an amazing facility, I REALLY wish I could have made it for the Gripfest event on Saturday(basically standing start single lap around the whole road course timed auto-x style)... I'm definitely planning on doing the event on October 29th!

Here was my fastest run, the car definitely had sub-90sec capability, just not me (sad2)

So I was originally going to run 700/550 because it is on a road course and I was expecting higher speeds, after walking the course I chose to try the 700s out back... holy s*** am I glad I did!!

My first run the amount of grip and amount of throttle you can give it just had me grinning like a complete idiot. I really wish I had an external microphone for my Gopro, otherwise you could have heard me going "Holy %&#@ this is awesome!" around nearly every slalom and off of every corner exit.

So I was running 700/700 springs, front shocks 1 turn from full stiff, rear shock dial on #5, and ran 33/38psi the whole day. I had no issues whatsoever with the setup, I just wanted to focus on driving the new setup more than anything.

There were not any spots that required a lot of rotation so I can't comment too much on that front, but higher speed stability was perfectly fine, throttle down and the rear plants, let up and it steps out without any wild snap oversteer or trying to swap ends or anything. This is by far the best the car has ever felt.

My first run was a 93.563+2(snagged one in the slalom along turn 1 on the actual course and one in the last Chicago box), second was 92.440+1 with Charlie(my codriver at the last event) to show him how the new setup felt, and my third run was a 90.621 clean, which ended up being my fastest run.


Run #4 it suddenly got some horrible understeer in every slalom. I wasn't expecting this because the tires were never hot to the touch, but that must be because of the ~1.5mi drive on the last half of the road course to get back to grid. Internally I'm guessing they were hot. I ran a 90.695, so just a hair slower.

I sprayed the tires and on run #5 I had already promised a ride along for another friend, in which I ran a 90.500 but +2.

It was a great time, and can't wait for a chance to go back again!


Here was my fastest run... still with plenty of room for improvement. Watching back I can see I wasn't getting left far enough to enter the slalom along the sweeping right turn 1 of the course. Would have helped overall corner speed for sure. Plus the launch in this one, and general un-smoothness.

Pic from the event...


I paxed 11th and came 22nd in raw time of 72 times. VERY happy with that. I beat my benchmark HS Fiesta ST driver in raw time, just missed him in PAX though.


http://tidewaterscc.github.io/archive-results/2016/04-April-24-2016.html

 

[flatlander937]

And then finally this past weekend I made my way up to New Jersey to finally meet Jeff(username jasyatz on here) in person. We got to work on Saturday about 2:30... Jeff leveled the spot for the scales while I replaced my torrington bearings for my coilovers since they were getting gritty and making the springs make a pinging noise when turning.



Before any adjustments(with driver):




After(with driver):





Notes page:




Note that we were not aiming for 50/50 cross weight. We're targeting having a nearly equal F/R bias on the left side as the left side.

So LF/(LF+LR) = RF/(RF+RR) is what we're looking to get close to.

We ended up with 61.1% for the left side, and 61.7% for the right side. I chose to leave it like that as I'm also looking to minimize the LF vs RF difference. Plus when I put a lighter battery in it that will further hurt the left F/R ratio vs right F/R ratio, BUT it will improve the LF vs RF.

IMO I don't think having it "perfectly" balanced any one way is correct, my goal was to get the best compromise of a little bit of every method.


For reference the car is ~2254lbs without driver. This is no spare, no tools, 3 bars on the fuel gauge, floor mats still in the car. And still a big honkin battery which really needs to go at some point (yupnope)

 

[flatlander937]

The next day we went to Metlife Stadium for the MotorSports NorthEast event.


It went pretty well! We got 10 runs, unfortunately all in the rain. I am pretty sure the 550s out back will be my rain setup, but we played around with 700/700 just to see if we could make it stick.. it was actually REALLY good on the whole course except ONE spot where a small river ran through an apex. There was some crappy pavement underneath too where it transitioned which may have also contributed to this video...

Ha!

However we played with tire pressures. Started with 33/38(just to see, this is what I prefer in the dry so far). We slowly dropped down until we ended at 30/28psi. Jeff's fastest run was on 30/29, min was on 30/28. We were in agreement that the 28psi in the rear felt better planted, it was just a matter of getting a clean run together. My fastest was on my very last run, Jeff's was on his second to last run.

Jeff beat me by 0.544 so I was happy I'm not too terribly far off of him. Because of how many runs we had we basically treated it like a rain test and tune.


Here was my fastest run:

And Jeff's fastet run:

Results are posted at MSNE here:
http://www.motorsportsne.com/
(Click on the May 1 results)

According to the MSNE PAX assignments(which are not SCCA standard), we finished 2nd and 5th in PAX. Me and Jeff were analyzing the data, and the cars at the top of the list are a GTI which is for DSP, a BSP WRX, and an HS Mini.

Basically we looked up nearly all the cars' SCCA class PAX times and compared to how they would look with proper classing and not the MSNE pax numbers... Jeff had first and I'd be in third behind the HS Mini. I would need to find 0.144 to end up second.

Overall it was a lot of fun, we got a bunch of runs and were packed up and ready to go by like 2:00 which was great.

I can't wait to run this thing in the dry now with the corner balance! I reckon I'll be doing some more experimenting with 700/700 vs 700/550 for rain events in the future. Probably more site dependent than anything. Smooth site and no standing water = 700s, rough site or standing water = 550s.

Ultimately learned some good baselines for tire pressure starting points at the next event though.

 

[flatlander937]

And a few pics from the weekend, I didn't take a whole lot because on Saturday we were pretty busy getting everything ready, and then Sunday it rained.

Here's Jeff getting ready to set up the scales:



At Metlife Stadium:



Jeff waiting in line for a run:



Me after crossing the finish and parting the seas with my car:



My car loaded down and ready to head back to VA Beach. I may have acquired a bunch of goodies leftover from Jeff's old 2... a second set of used wheels with near new RE71Rs, a spare transmission with 19k miles on it(to eventually have a limited slip added to it), a Racing Beat exhaust, plus a bunch of small things like more wheel spacers, center caps, etc.



Here's a better look at the RB exhaust... the giant dent on the bottom isn't visible when installed fortunately It was caved in from his old Tripoint sway bar. It sounds PERFECT. Not loud, has a great tone, doesn't drone any more than the vibrations my motor mount already makes.



And a better look at the tranny I brought back from Jersey. (silly) It'll probably be tucked away for a couple years, I've got to slow down on blowing money so I'll probably stay in STF for a good while.

 

[Zach@DDMWorks]

If the surface is wet you will probably want to lower your rear rate. The issue is that you won't be able to get heat into your rear tires. I can't keep heat in the rears in the wet on track, so there is no way you could do it at an autocross course.

 

[Cossamaximus]

Sorry to jump in here on your thread, but I noticed you were talking about rear springs etc...and I saw the pictures a few pages back. Well my question is...why does everyone install their rear springs with the adjuster at the bottom?? I have my rears with the adjuster on the top, just like the manual said to do, as well as they guys at KW told me too... so who's right and who's wrong, or doesn't it matter.

Again sorry for thread hi-jack.

Tim

 

[flatlander937]

If the surface is wet you will probably want to lower your rear rate. The issue is that you won't be able to get heat into your rear tires. I can't keep heat in the rears in the wet on track, so there is no way you could do it at an autocross course.

Oh definitely. The 550s out back worked amazing in the rain at the last wet event I did. The 700 rears are incredible in the dry, this was basically just an experiment to see and confirm what was suspected(700s too much for the rear).

Plus we just corner balanced it on 700s the day before

To be fair, that ONE spot was the only problem area on the whole course. We could give it 100% full throttle coming out of just about every single turn with minimal(if any!) wheelspin.

We WOULD have switched to the 550s but we were taking runs switching drivers as soon as we got back to grid. There wasn't enough time to make a change.

We were counting on it being essentially a "spin it or win it" type of setup for this particular lot.

I do think at ACU4(large flat concrete lot) in the wet, if it's not tons of standing water, the 700s may well be better. I'll have to test there if the conditions are right. At Pungo, no way in hell 700 rears will work in the rain. They may even be too much in the dry, but won't find out until October or something when our next event there is scheduled.

Hopefully Jeff chimes in here too on his impressions of the car.

Sorry to jump in here on your thread, but I noticed you were talking about rear springs etc...and I saw the pictures a few pages back. Well my question is...why does everyone install their rear springs with the adjuster at the bottom?? I have my rears with the adjuster on the top, just like the manual said to do, as well as they guys at KW told me too... so who's right and who's wrong, or doesn't it matter.

Again sorry for thread hi-jack.

Tim

My whole setup is hodge-podged together stuff and custom fabricated parts.

They're rear height adjusters for a Toyota Yaris. They just happen to fit the lower buckets better.

There's no real problem with top vs bottom, just depends on what the manufacturer calls/designs it for.

No worries of thread jacking, this is for learning. Any questions you have, fire away!

 

[Cossamaximus]

Thanks, just noticed the difference on few mazda 2 examples.

 

[Zach@DDMWorks]

My rears are on the top and they are just from Ebay. I have them there because it was easier to zip tie them up along with the springs.

Tony also I think you had less wheelspin in the wet because you were driving a little easier than normal because you were concerned about the rain. From what I have seen of your other videos you seem to overdrive a bit mid corner which will cause more wheelspin getting out of the corner.

 

[jasyatz]

I can honestly say there was no massive amounts of wheelspin mid or corner exit. Got some off the line, but after the 3rd launch, we both found the sweet spot of grip and were able to get the most out of the uphill to off camber first corner.

The was really only one spot that I really pedaled and puckered and that's where I spun it twice. It was a fast transition (45/50 in the rain) crossing perpendicular over a pavement seam and then a left sweeper uphill as you passed through a running "stream" heading into a tight decreasing radius right hander. Any heat you had in the rears instantly evaporated.

I agreed a softer rear would have made it easier to drive; possibly quicker but we easily gave up a half second coming through that section alone. i did notice a fair amount of wheelspin and push coming off the downhill off camber 90 left uphill into the finish, but a better entry and unwinding earlier would have taken much of that away.

Overall the car did exactly what I thought it would. Dominant in the rain but stiffer than I'd have started with. BUT we left the 700s to see if it was manageable if you had an event where it has mixed weather. It will be fast in the dry, not RSX S fast, but it will hold its own. The Konis do a remarkable job keeping the front in check and the AGXs in the rear never felt overmatched by the 700s. It felt a lot like the BCs, but I think there was a bit more slow speed control with the Konis.

Overall I can't thank Tony enough for coming up and letting me drive it. I miss having a car that turns well. And holy crap the brakes are fantastic! Like plant your face on the steering wheel awesome.

 

[flatlander937]

My rears are on the top and they are just from Ebay. I have them there because it was easier to zip tie them up along with the springs.

Tony also I think you had less wheelspin in the wet because you were driving a little easier than normal because you were concerned about the rain. From what I have seen of your other videos you seem to overdrive a bit mid corner which will cause more wheelspin getting out of the corner.

Yeah I do overdrive some generally... But the run above was my last one... I was giving it everything I could to try and go faster(than Jeff... Haha).

The front grip from the 700 rears is night and day vs the 550s. It was run in the dry at NCCAR like this and it was awesome there as well. In the wet it just becomes a matter of whether the rear will stick or not. You do need to have a bit of restraint yanking the wheel abrubtly in the wet on this setup, and I did drive accordingly.

If you throw out my first run plus the two that I spun it when feeling out the limits, all of my times were within 1.1sec of each other.

I can honestly say there was no massive amounts of wheelspin mid or corner exit. Got some off the line, but after the 3rd launch, we both found the sweet spot of grip and were able to get the most out of the uphill to off camber first corner.

The was really only one spot that I really pedaled and puckered and that's where I spun it twice. It was a fast transition (45/50 in the rain) crossing perpendicular over a pavement seam and then a left sweeper uphill as you passed through a running "stream" heading into a tight decreasing radius right hander. Any heat you had in the rears instantly evaporated.

I agreed a softer rear would have made it easier to drive; possibly quicker but we easily gave up a half second coming through that section alone. i did notice a fair amount of wheelspin and push coming off the downhill off camber 90 left uphill into the finish, but a better entry and unwinding earlier would have taken much of that away.

Overall the car did exactly what I thought it would. Dominant in the rain but stiffer than I'd have started with. BUT we left the 700s to see if it was manageable if you had an event where it has mixed weather. It will be fast in the dry, not RSX S fast, but it will hold its own. The Konis do a remarkable job keeping the front in check and the AGXs in the rear never felt overmatched by the 700s. It felt a lot like the BCs, but I think there was a bit more slow speed control with the Konis.

Overall I can't thank Tony enough for coming up and letting me drive it. I miss having a car that turns well. And holy crap the brakes are fantastic! Like plant your face on the steering wheel awesome.

(drinks)

Thank YOU Jeff for helping to balance the car and sending me home with all your old Mazda2 goodies

I was glad to be able to put someone else in the car who KNOWS how to drive the car fast, and set a benchmark and get some input on setup/etc.

 

[Zach@DDMWorks]

When you had 550 in the rear was that with a rear bar or not I can't remember.

 

[flatlander937]

Last year I tried with and without when I was on 550/450. I believe it was without for my first TSCC event this year and also for the ODR event.

I only played with the rear bar on the street mostly this season. I have a test and tune coming up where I'll try it out again hopefully. Our Pungo lot is not an ideal place for setup testing, it's a rough crappy lot, so the bar does some weird stuff there.

 

[Zach@DDMWorks]

I was just thinking if you had the 700/550 without a rear bar that is going to be rather understeery and wheelspinny.

 

[flatlander937]

I was just thinking if you had the 700/550 without a rear bar that is going to be rather understeery and wheelspinny.

It was still wheel-spinny some(not as bad as 550/450 w/ rear bar though), but wasn't understeery. It was just incredibly neutral. The rear would come around if you lifted mid corner, but it was very slow to do so and I needed more of it.

The 550/450/rear bar rotated enough, but it was a bit more of a snap into lift oversteer.

I am going to give Jeff's soft rear sway bar(made from some kind of GM control arm that has some stiff bushings at each end) to see if that's a good middle ground.

The 700/700 setup feels REALLY good with no bars in the dry on asphalt at NCCAR. Our next event(and many after) are all on concrete at ACU4. Not sure the rear will need to be looser or tighter.

With 700/700 it does still lift the inside... Even in the rain so I don't think a bar will gain much overall grip or help power down at all. Just change the lift oversteer severity/abruptness.

I'm currently letting a FiST owner borrow the DDMWorks bar so he can decide if he wants to buy one for himself or not

 

[Zach@DDMWorks]

I was just wondering because I think your 700F 700R setup without bars is very close to the same balance as what I am running if I am remembering the stiffness of the stock rear beam correctly.

Zach

 

[flatlander937]

I was just wondering because I think your 700F 700R setup without bars is very close to the same balance as what I am running if I am remembering the stiffness of the stock rear beam correctly.

Zach

Yeah I remember running the numbers a while back and that was why I chose the 700/700. The roll stiffness was very close to 700/550 with rear bar(which Jeff used for some time, maybe 700/600?). I used estimated beam stiffness values based on how much deflection there was on one spring while jacking up the opposite side(with no spring).


I can't necessarily explain it, but they feel completely different.

Some brainstormed ideas why:

The stiffer springs keep the rear beam flatter to the ground. The outside spring doesn't compress as much, the inside spring doesn't extend as much when unloaded. Inside stays on the ground longer.

The bar works completely by robbing inside spring rate to supplement the outside. It only works when the inside spring starts to compress, so it's pulling the inside earlier/sooner into a turn. Feels great for quick transitions at low speeds, but going through a higher speed slalom was where it got tough to keep from swapping ends.

Steady state grip is pretty similar.

Exiting a turn under throttle is the biggest difference.

The heavier springs keep the inside front wheel planted because it's not compressing as far in the rear outside... The bar relies on the bushings to not flex in the beam before it starts doing anything.

There's a very distinct difference in predictability in the two setups. I prefer the 700/700 so far. What remains to be seen is if 700/700/rear bar is good or bad. The breakaway of the 700s out back is incredibly predictable(except when driving through a downpour river that runs through your apex ) and I want to keep that.

 

[Zach@DDMWorks]

I don't agree with a couple of the things you said mainly because you comments could be said for a larger rear bar as well. Not saying your setup is bad, just a different way to look at it which is always interesting. Especially since somehow I don't have the wheelspin issues everyone keeps mentioning. I am going to think about what you mention with the rear bushings though. There should be a difference there, but still not sure how it effects it. Also off the top of my head the effect should be really small. going to be a bit before I have time though. Very busy, like 4-5 hours of sleep a night all week for multiple weeks kinda busy.

Also when did you make the rear shock change in all of this. That could be a factor as well for when you saw less wheel spin.

 

[flatlander937]

I don't agree with a couple of the things you said mainly because you comments could be said for a larger rear bar as well. Not saying your setup is bad, just a different way to look at it which is always interesting. Especially since somehow I don't have the wheelspin issues everyone keeps mentioning. I am going to think about what you mention with the rear bushings though. There should be a difference there, but still not sure how it effects it. Also off the top of my head the effect should be really small. going to be a bit before I have time though. Very busy, like 4-5 hours of sleep a night all week for multiple weeks kinda busy.

Also when did you make the rear shock change in all of this. That could be a factor as well for when you saw less wheel spin.

Yeah, I'll let you run the numbers and stuff, I'm mainly flying by the seat of the pants


I've had the rear shocks since December. They definitely did help... 550/700 was miserable at Pungo on my old Koni rears, bounced like hell at the last event of the year.




Your lack of wheelspin.. Are you talking about on track or autocross? At higher speeds I don't think it'd be such a concern being in taller gears comparatively. Our courses locally are normally pretty small/tight so small radius turns are kind of necessary.



In other news the 2 got aligned on a real machine today(not with my EYEcrometer).

It was set to -2.1deg camber on both sides, 4.1/3.8deg caster, and zero toe.

Aligned by eye a few weeks ago all that needed corrected was the right side camber(was about -1.9), caster was brought just a bit closer together, and toe was at about -0.37 total.

Because of the stupid amount of driving I do I want zero toe for tire wear reasons.