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*The Electrician*
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Discussion Starter · #1 ·
Just got back from my first autocross in my Mazda 3 GT. I have done autocross in multiple vehicles and was really excited to try out the Mazda 3 GT on a dry course. I can tell this chassis has tons of potential and I am definitely taking a shot at the H-Street title next season. The stock dunlops actually held up decently, had them at 45psi tho to keep the sidewalls from rolling. Turn in was great, the braking would be better if I had the tires I want, and the overall weight transition was superb. I definitely lost time on braking and a little bit on the high speed laterals but I managed to not come last lol so Im happy with that result. Especially considering how many faster cars were there(corvettes, sti's, boosted frs/brz's, focus RS) needless to say I was very much outclassed lol. I had an absolute blast and am excited to run again next month. This Mazda 3 has great potential and I plan to extract everything I can on the autocross courses within the street class restrictions. Might add a few more notes later after a nap and some dinner.
 

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Gearhead
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Exciting that you enjoyed A-X'ing your Mazda 3, and that not only are you happy with what you have, but see specific steps to improve it.

Here's to more progress as you upgrade a few things!
 

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If you enjoyed it stock, you should try it after making some handling improvements. Springs/Shocks/Wheels/Tires/RSB

IMO, stock is woefully inadequate
 

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If you enjoyed it stock, you should try it after making some handling improvements. Springs/Shocks/Wheels/Tires/RSB

IMO, stock is woefully inadequate
Same as with most cars out there, especially anywhere near economy class.

I do have to hand it to mazda though, a stock 3 handles extremely well for what it is. I don't expect much from any car in its class and I was pleasantly surprised.

From what I understand the only similar car that is comparable to the 3 for handling is a VW. I won't touch their cars until they become reasonable to work on. In other words, never.
 

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If you enjoyed it stock, you should try it after making some handling improvements. Springs/Shocks/Wheels/Tires/RSB

IMO, stock is woefully inadequate
Well not really. It is not bad compared to some others like it. And yes there are improvements that can make a big difference.
However, making such changes could put a car in a different class where it would be far less competitive. Kind of defeats the purpose I think.
 

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*The Electrician*
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Discussion Starter · #7 ·
Well not really. It is not bad compared to some others like it. And yes there are improvements that can make a big difference.
However, making such changes could put a car in a different class where it would be far less competitive. Kind of defeats the purpose I think.
You've hit the nail on the head arathol. Springs will never happen, I need the ground clearance for winter up here, and my racing class changes. Struts, too much money for not enough gain. Rear swaybar, class changes and then I wouldn't be competitive anymore without spending on the entire suspension package and for a daily driver its just not worth it. Id rather save that money for a house and then for a summer toy like a boosted BRZ when Subaru finally gives us one, or a Focus RS. Both seems to perform exceedingly well this past weekend and interest me far more than a corvette. When I can afford it I will definitely be grabbing some super sticky tires and I think that plus seat time and the Solopro school next season will give me a fighting chance at taking the local H-street title in 2018. If I manage to take a title I will probably jump up to nationals and have my ass handed to me by a bunch of Fiesta ST's lol but it will still be fun.
 
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*The Electrician*
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Discussion Starter · #8 ·
*Round 2*

Well went for round 2 today on a more open course and had a blast. Beat a 2007 Civic Si in PAX time, couldn't catch him in RAW, was within about 2 seconds. But even more importantly, beat an R34 GTR V-Spec in PAX time muahahaha. And no he was not a newbie either, so Mazda 3 ftw :D

I go back tomorrow for round 3 and then Im giving my tires about a month of rest lol. Definitely rolling onto the sidewall more than Id like but Im at 45psi so their up as high as I feel safe with a 51psi max rating on the oem Dunlops. I can't wait for a RSB and better tires, I can start chasing the stock FRS/BRZ's once I get those.
 
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Super Moderator
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Are you sure the sidewalls are rolling that much? 45psi seems a bit high. You might be losing time by doing this. You're running on the center of the tire instead of the entire tread face. With pressures that high you're losing a significant amount of grip that otherwise would have come from the outer portions of the tread face. Have you tried experimenting with different pressures? I bet if you knock it down a few psi you might be faster.
 

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*The Electrician*
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Discussion Starter · #10 ·
Are you sure the sidewalls are rolling that much? 45psi seems a bit high. You might be losing time by doing this. You're running on the center of the tire instead of the entire tread face. With pressures that high you're losing a significant amount of grip that otherwise would have come from the outer portions of the tread face. Have you tried experimenting with different pressures? I bet if you knock it down a few psi you might be faster.
I don't have tire chalk but I can definitely see the front sidewalls rolling over the edge a bit. I'll take pictures tomorrow so you can see. I will experiment I suppose and try 42PSI cold and see what happens.
 

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I don't have tire chalk but I can definitely see the front sidewalls rolling over the edge a bit. I'll take pictures tomorrow so you can see. I will experiment I suppose and try 42PSI cold and see what happens.
Yeah I can see that happening. More than a small part of that is due to the strut suspension and the way it changes camber when pushed hard. Under load or compression, you lose negative camber and move into positive camber. This is probably why you are seeing the front sidewalls scrubbing.
Are camber changes allowed in your class? There are ways to make a couple more degrees negative camber if its permitted.
 

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*The Electrician*
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Discussion Starter · #12 · (Edited)
Yeah I can see that happening. More than a small part of that is due to the strut suspension and the way it changes camber when pushed hard. Under load or compression, you lose negative camber and move into positive camber. This is probably why you are seeing the front sidewalls scrubbing.
Are camber changes allowed in your class? There are ways to make a couple more degrees negative camber if its permitted.
I don't have pictures yet, too tired. I tried 43psi and it sucked lol. I then went back to 45psi and it was a tight course today with many pinch points so I maxed my tire pump and got to 48psi front and 47psi rear for my 3rd/4th morning runs and it made all the difference. It was simply amazing in the slalom with that tire pressure up at 48psi/47psi, was able to zip thru them and felt very stable. I unfortunately kept losing grip on the pinch points and had to saw the wheel alot today. Overall I did fairly well for the only H-street class car in attendance. I'll post more tomorrow, very tired, and burnt lol, note to self, use sunscreen!!!!

PS, definitely want to look into the suspension/alignment deeper in the next month here. I have also decided to possibly ditch H-street so I can mod a bit further but I am loving my PAX modifier in H-street so we'll see.
 

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Sounds like you need new tires desperately. Those all season Dunlops can barely get the car down the road in a straight line. I don't think they are particularly suited to this type of driving.:laugh2:
You might have to bite the bullet and get a set of dedicated performance tires.

If you want to get around those tight corners without all that understeer, you need to get that sway bar in place, get some camber in those front tires and look into a better all around performance alignment. I have about -2.5° camber on the front and -1.5° in the rear, and near zero toe in the rear.
The problem for you is class restrictions. You will need to change classes if you make the changes needed to do all these things. You're pretty limited in HS, just tires, rims, shocks, brake pads and one sway bar, and you can't go outside of manufacturer spec for alignment. :frown2:
 

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*The Electrician*
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Discussion Starter · #14 ·
Sounds like you need new tires desperately. Those all season Dunlops can barely get the car down the road in a straight line. I don't think they are particularly suited to this type of driving.:laugh2:
You might have to bite the bullet and get a set of dedicated performance tires.

If you want to get around those tight corners without all that understeer, you need to get that sway bar in place, get some camber in those front tires and look into a better all around performance alignment. I have about -2.5° camber on the front and -1.5° in the rear, and near zero toe in the rear.
The problem for you is class restrictions. You will need to change classes if you make the changes needed to do all these things. You're pretty limited in HS, just tires, rims, shocks, brake pads and one sway bar, and you can't go outside of manufacturer spec for alignment. :frown2:
Yeah I may bite the bullet and goto up a class or two, but, I love my H-street PAX modifier lol. I have to dig into the rules a bit more to find out how to accommodate the alignment, hopefully in STS. Its looking like I will probably do a front and rear swaybar with custom alignment to curb this understeer during the slower tight sections. I think one more event and I am done for the season anyway. Dedicated RE-71's 225/50/R17 on a separate set of rims would be nice but then I need a proper floor jack and a torque wrench, more money that I just don't have available right now. I already have to get 16's for winter plus studded tires too, Id end up with 3 sets of rims for this car and that's after I sell the OEM 18's. The dollars are stacking up against me pretty badly. I was thinking used 17's for autocross, maybe TSX rims? I still have to learn about offset, just haven't spent the time on research yet to figure all that out. If I can use RSX 16's for winter that would be ideal too as they are generally fairly cheap and I hate using steelies for winter. Or older Mazda 3 rims in 16inch perhaps. Ive got the AEM drop in filter now and probably still want the AEM short ram intake as I love intake noise from 4cyl's. Especially if Im changing classes anyway for the alignment. The exhaust should be done sometime in July and Im debating about the intake at the same time. Exhaust Im guessing will run me $500CND max from my local shop doing a custom single exit for me. Then Ive got another $500 available but I doubt I can do the swaybar and alignment parts plus install for under $500CND.
 

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If you are really getting RE71s, you better get in line for them now. When the season starts they are near impossible to get. 225s might be bit wide for you. If you are going with 7" rims, 195s or 205s might be better. Keep in mind that RE71s are quite a bit wider than many other tires in the same width. 195/50 on a 7" rim should be a good combination.
205, RE71s vs Potenza S001s


You'll want a light wheel, + 45mm offset is a common size. I believe your class allows ±7mm for wheel offset. Factory is +50mm.
Check class restrictions for width, usually street stock is limited to OEM width, so 7".
Nobody ever said racing was cheap. If you want to be competitive, you'll need to have equipment thats at least as good as what the other fast guys have, especially if you move up to ST or higher.
 

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*The Electrician*
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Discussion Starter · #16 ·
For now this is mostly for fun, being competitive is likely more money than I care to spend. My gut says 225 wide is what I need to chase some faster raw times and from what I was told that is allowed in H-street. But if I do a custom alignment and Im fairly certain I will be, then it won't matter how wide I go. I suppose if I had more power 235 might be more useful but I think 225 RE71's will be the right fit for my dedicated autocross tires. Once I jump to STS I am allowed 8inch wide rims so I need to find a 17x7.5 or 17x8 rim under 18lbs per rim, might not find that in anything oem so I could be stuck paying for new rims or biting the bullet on weight. The 2010 TSX rims are 7.5 and 55offset which may suit my needs. Im going for RSX 17's for daily driving and RSX 16's for winter. Oddly enough the RSX 16's only weight 16lbs lol so my winter wheels will be the lightest.
 

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Just wanted to say good for you for getting out there, and even more so for actually having a plan when it comes to racing! Both are hard, regarding the first it's always easier to put it off, and regarding the second it's easy to either burn out fast or modify haphazardly. Good luck, go give em hell.
 

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*The Electrician*
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Discussion Starter · #18 · (Edited)
Just wanted to say good for you for getting out there, and even more so for actually having a plan when it comes to racing! Both are hard, regarding the first it's always easier to put it off, and regarding the second it's easy to either burn out fast or modify haphazardly. Good luck, go give em hell.
Thank you, I have done autocross on/off for a couple years now with various FWD's I have owned. I have also done rallycross and some ice racing too. What I want is a stage rally car lol but thats expensive and my new Mazda has made me poor haha. My plan for racing is simply to have fun :) and I always do. What I like to do is find others who are close to my RAW times and compete with them regardless of class. Its just a friendly competition at that point and for now that works really well to push me to go faster. Eventually I do want to chase some top 10 RAW times and top 10 PAX times but I need a different car for that lol. Eventually I may go for an FRS as they seem to do very well. Even the new ND Miata is scoring top 10 times in our club. Racing is in my blood and that will never change. When I first got my license 15 years ago I always did things to scare my friends when driving, like driving super close to parked cars at higher rates of speed, never even clipped a mirror, scared the crap outta all my friends lol and I loved it. I knew back then there was something different in me that none of my friends had when it came to driving, I quickly became the designated driver because of it too lol. It wasn't until about 10 years ago that I discovered autocross and eventually rallycross, stage rally, and ice racing. I have the raw talent to do very well, just need the money for seat time. One of my dreams is to take the rally training school in Washington at the Dirtfish racing academy. But as it is with all good things, it will come in time, and I will be ready.
 
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*The Electrician*
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Discussion Starter · #19 · (Edited)
Finally got some pictures of my Mazda at autocross. Im going to purchase them shortly so I can have them available to post embedded and without the watermark. Here they are, about halfway down the page.

https://www.flickr.com/photos/locotoy_ian-g/albums/72157683021657024/page5

I can ALMOST tripod, mesa needs better grip asap for that. Then we get to see some baddass body roll lol, until I get a swaybar.
 
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