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Old 17-03-2012, 12:39 PM   #1
TheMAN
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Thumbs up AutoExe chassis braces installed!

Thanks to Rupewrecht a couple of months ago for finding these rare AutoExe chassis braces, I managed to get them finally! It was very expensive but it's very worth it for my highly modified Protege.



It's unfortunate that AutoExe discontinued these braces back in May 2006. I always wanted them because I knew they had engineers that tested and designed these braces, unlike other companies that just copies from others or just make parts without much thought. When I finally had money to buy these 6 years ago, they were discontinued 2 weeks before!

So that opportunity a couple of months ago was something I didn't want to miss. The auction was expensive but I wasn't going to miss out on these again.

This is a 5 piece "member brace set" that is meant to be combined with the AutoExe lower arm bar. They are meant for the regular Protege/Familia/323s only and not for the MazdaSpeed Familia, MP3, or MazdaSpeed Protege because the rear crossmember is different. I have the MazdaSpeed sway bar set, which mean I have the MazdaSpeed rear crossmember. But this didn't stop me. I managed to make it work!

I will explain each piece of the braces as I go along with each pic to make things understandable.


First off, I installed the rear crossmember centre support brace. It is thick gauge steel that's welded together into a box frame, unlike the stock support brace that's only thin stamped steel. This stronger support brace prevents the "U" shaped rear crossmember from deforming in the middle during high suspension loads/stresses.



Installing this brace involves lowering the rear crossmember. It could be done without taking the crossmember out of the car. There isn't as much space to do as taking all the lateral links and crossmember out, but it's worth it because you don't really have to align the suspension again afterwards


You may have noticed earlier that the stock brace uses 3 bolts to the chassis with 2 to the crossmember. The AutoExe brace doesn't use the extra bolt because the better brace doesn't need it
Anyway, here is it all bolted back up to the car... no interference issues with the USDM evaporative emissions system either




Then came the very painful part... took a lot of expletives to get this done!
There's those two "L" braces that ties the rear crossmember to the frame. It attaches to one of the sway bar bracket mounting holes, one of the rear crossmember mounting holes, then finally it ties to the frame which requires drilling holes into the frame to allow it to bolt in. The "L" braces stabilizes the rear crossmember to prevent it from shifting during hard cornering or over uneven pavement.

Normally this isn't an issue if you have a regular non-Mazdaspeed rear crossmember, but it is with the MazdaSpeed crossmember because the rear sway bar mounts a little differently. The MazdaSpeed rear crossmember has reinforced steel around the mounting holes and it uses 2 bolts to mount the sway bar bracket instead of 1 bolt/1 nut combination on the regular crossmember. This really means the "L" brace mounting hole won't line up to the MazdaSpeed rear crossmember's sway bar mounting holes!


As you can see, the difference is very slight... 3-4mm at the most. No problem, I just got my Dremel out and grinded the hole bigger! This was very time consuming as I didn't want to make the hole too big, so back and forth to the car to test fit it!



After I verified it worked, I touched up paint on those braces and set out to find longer M10x1.25x35 flange head class 8 bolts to replace 2 of the stock sway bar mounting bolts. The stock bolts will become too short once the brace is in place since it sits over the sway bar brackets. I went over to my friend's shop and found some I needed in his bucket of bolts.


Of course most importantly, now that I was able to bolt 2 of the 3 points on, I finally could accurately mark the drilling location on the frame. The instructions said to drill the mounting hole to 9mm (about 3/8"), and another hole 44mm away (centre to centre) to slip the mounting bracket plates into the frame to 18mm (about 11/16"). I bought a stepped drill bit from Harbor Freight tools just for this purpose as it it's on sale this week for $5.99 Drilling the frame was NOT fun at all. There's no room to put the drill in while all the suspension parts were in place. I ended up using a drill bit extension to carefully drill the holes (after drilling very small pilot holes of course ). The USDM rear frame is stronger, so it's very hard to drill through. The metal is almost 10mm thick! Anyway, the 11/16" hole didn't let the mounting bracket plates fit through, so I ended up drilling all the way to 3/4" instead and it worked perfectly. After the holes were drilled, I touched up the paint in those holes too to prevent rust. I also had some Wurth rust proofing spray around, so I sprayed some inside the frame rails too.

continued in next post...
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Old 17-03-2012, 12:47 PM   #2
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Next issue that the instructions didn't seem to mention... the brake piping...
the rear left side brake pipe is in the way of the "L" brace. I had to bend it out of the way a little. The next dilemma was whether to sandwich the brake pipe between the brace or make it go below it. After some thought, I decided it was best to not bend the brake pipe any more and to just sandwich it between the brace instead. What I needed to do though was add some foam padding between the brace and the brake pipe to prevent rattle noises and to prevent damage to both parts.



Once these issues were taken cared of, I regreased the rear sway bar bushings and bolted everything up. As I said earlier, the mounting brackets are little plates with a nut attached to it so that you can slip through the larger hole you drilled in which you hold it in place while you insert the bolt on the outside and bolt the brace in place.


The bolts that came with these used braces were a little rusty, so I spent $11 on some quality stainless steel bolts, washers, and lock washers of the same style.





The easy ones to do were the fronts! There's already an existing oblong hole at the front end of the frame rails. You just simply reuse those holes and drill another hole that's 18mm big 44mm (centre to centre) away from the existing holes. Of course it's still recommended that you do a test fit then mark the holes first before drilling. One thing I had to be careful with the front frame rails... it doesn't hang very low, so it's not very far from the floorboard! What this meant was, I had to be careful not drilling too far in, or I risk drilling through the floor! I did a quick measure and determined that I could only drill to the 11/16" step, no further to the 3/4" step. So this meant I had to finish up making the hole slightly bigger with a Dremel grinding stone.



And of course, the obligatory "overall" shots
Front (lower arm bar already had for years):






Driving impressions:
When driving normally, the back end of the car feels MUCH MUCH more solid. No more hollow noises going over bumps, less suspension clunking. It's hard to describe, the noise differences, because it's quite subtle and so it's hard to know what you're missing if you don't have these braces! But as far as actual feel, the suspension is more compliant and supple over pot holes and cracks. The shocks actually dampen better now without the unnecessary metal movement/play that makes things worse. Less vibrations = GOOD.

The front end seems a little more solid too. It maybe in my head, but the movement in the engine doesn't seem to transfer as much vibration shocks to the chassis any more. It also seems that torque steer is LESS when I'm taking off from a standstill at full throttle!

As far as handling, it seems a little more flat, so I think my cornering speeds are slightly higher now. Overall though, I didn't have to adjust my driving for the changes. The AutoExe lower arm bar made a bigger difference in handling since it ties both sides of the "U" shaped front crossmember together, which prevents the each side of crossmember from folding in against each other, thus maintaining suspension geometry better which in turn allows greater predictability, control, and handling
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Old 17-03-2012, 01:34 PM   #3
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top job Edwin.
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Old 17-03-2012, 01:40 PM   #4
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Thanks Ed for a great write up.
Looking forward to fitting my set still!!!
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Old 17-03-2012, 02:39 PM   #5
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Great write up! Would be good to see something like comparable lap times, just to see how much of a difference the bracing makes.
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Old 17-03-2012, 02:42 PM   #6
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Good work Edwin!
I'm sure that while the improvements are subtle they seem to have been an improvement in all areas.

I think I might have to keep an eye out for a set - I will probably need 6 years to save for one
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Old 17-03-2012, 03:26 PM   #7
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Originally Posted by phildough View Post
Thanks Ed for a great write up.
Looking forward to fitting my set still!!!
Well Phil you should not have blown up your gearbox then!
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Old 17-03-2012, 03:30 PM   #8
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phil doesn't know how to drive, that's why he stuffed up his motor and gearbox
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Old 17-03-2012, 06:42 PM   #9
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Well Phil you should not have blown up your gearbox then!
Excuse me. Who destroyed my gearbox so I couldn't even make it home????
What are you talking about, you are the one who's fitting these horror braces at the same time as installing the new gearbox.
And if a extra special job is done on my car I will be maxing out my duty free allowance for you.

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phil doesn't know how to drive, that's why he stuffed up his motor and gearbox
Ed, I have been driving for 20 years and have had 10 cars and have never had an accident where I was at fault, I also have my Heavy Rigid Truck licence, Forklift, Stock picker and reach truck licences as well.
So yes I think I know how to drive, maybe more than my car can handle which is why im upgrading to a G series gearbox and will soon be getting a M Factory LSD.
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Old 17-03-2012, 08:22 PM   #10
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phil, why u so mad?
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Old 17-03-2012, 09:20 PM   #11
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ok, so in case anyone was wondering about the differences between the USDM rear frame rails and the non-US ones, some bloke in Japan wrote this and took the pics of his install:
http://minkara.carview.co.jp/smart/u...1941/note.aspx


First off, his is a wagon (Astina), not a sedan like what I have... so you can see some shape differences in the frame rails, but that doesn't matter and isn't the point... look at the mounting bracket plates used to secure the "L" brace onto the chassis... you can see part of the brace sticks out of the hole, unlike mine that sits basically flush with the outside! It's hard to tell in that low res pic, but you can almost see that the frame rails are half the thickness!

So in other words, I'm glad my car had a stronger chassis to begin with! I guess sometimes those strict US crash laws become an advantage But interestingly, the EDM sedans (Ireland/Malta included) have the same stronger rear frame rails as the US version.. it's only the EDM wagons have the same weaker rear frame rails as with the rest of the world, unlike the US wagons (Protege5) which has the stronger frame rails
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Old 25-03-2012, 01:14 PM   #12
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Today I looked through the back wheel and saw there's a small problem... because the MP3/MSF/MSP rear crossmember forces the "L" brace to sit out further, it rubbed on the front lateral links:



So what I did was got the Dremel out and grinded the brace down a little... took a couple of millimetres off which make it go from 1-2mm clearance to 4-5mm


All better now, I think!



I am waiting for the paint to dry, and I will go take it out for a spin tomorrow to see if this is good enough after I toss the car through a couple of corners
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Old 25-03-2012, 05:02 PM   #13
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I guess when they originally design them, that wasn't for a car as low as yours. Judging by the angle that the latteral links are pointing, you much be really low.
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Old 25-03-2012, 05:45 PM   #14
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not really
car is only lowered 25mm

autoexe springs lower even more

the problem is, the sway bar mounting point is thicker on the MSF/MP3/MSP crossmember, so that means the whole sway bar bracket sits out further away from the crossmember than the regular one does.... in other words, the the sway bar bracket is closer to the front lateral link than the regular sway bar..... autoexe designed these braces for the regular crossmember, which is why I had to modify the hell out of these
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