AutoExe chassis braces installed!

By odd chance, I managed to get these rare AutoExe chassis braces a couple of months ago from Japan. It was very expensive, but it's very worth it since my Protege is now more than just a converted MSP.



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! :mad:

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...

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

so why these instead of those V-braces that most people get? Well like I said, I thought these had better engineering thought put into it, plus those V-braces reduces ground clearance and it involves unbolting the rear lateral arms, which means having to align the suspension again (jerkit)... besides, I haven't heard of any other braces that helps anchor the front crossmember better to the chassis. The front GT spec ladder bar (not the GT spec/Cusco/Autoexe tie bar that goes between the control arm mounting points) doesn't do much over the stock tie bar other than looking prettier.

but down side is, you won't be able to install the sway bar "clunk fix" brackets since those brackets go right where the rear crossmember bolts in... but it's not a big deal for me... I have the very stiff JDM MazdaSpeed B-Spec suspension, so there's less load on the sway bar, thus I almost had no sway bar clunks to begin with! Another thing is, those lime green JDM MazdaSpeed adjustable rear struts don't have the beefier sway bar tab that you find on aftermarket Tokico struts or stock MSP/MP3 struts. I didn't want to put more stress on those mounting tabs than I needed to! Yashooa broke his already (he has the same suspension I do) and he has the "clunk fix" kit... it was fortunate that Ari at Rotary Performance was able to reweld them and fabricate reinforcing metal then welding that on

I always wondered if there was a matching set for the tie bar. Looks like it makes a big difference... Well Done...

oh and I heard from someone that if 10 people can commit to buying these, autoexe will resume limited production of these braces.... not sure if it's true... check with mazmart or corksport since they're the official US distributors

I'm pretty sure that when these braces are combined with the GT spec ones, the car will be pretty solid!

TheMAN said:

oh and I heard from someone that if 10 people can commit to buying these, autoexe will resume limited production of these braces.... not sure if it's true... check with mazmart or corksport since they're the official US distributors

I'm pretty sure that when these braces are combined with the GT spec ones, the car will be pretty solid!

Click to expand...

I would be in on that!

Well done again Edwin!

How much did it run you? =)

Good info. So you do you just read up on overseas auctions/sale ads to track these down?

Ok, I guess some clunk fix brackets will work with the rear braces:

and the famous Delsing ones:

since the Delsing brackets uses those big solid spacers, it'll probably be a good idea to make/use a custom spacer tube that sits inside the mounting hole in the AutoExe brace so that when the Delsing brackets bolts over it, the forces will be directed to the crossmember instead of to the AutoExe brace.... definitely some custom fabrication will have to be done to let you use both the Delsing brackets and AutoExe braces together... but it looks relatively simple enough

Pretty cool!

HoLy s***!! I would definitely wanna a set!! Nice score!!

Thats an awesome write-up. I wish these parts weren't uber rare, they belong in the 'unobtanium' category for me here in the US.

nice stuff, I doubt 10 people will commit once they get the prices though

id be down. i really like those pieces....

How much weight did you add to the car? I know it's a very low center of gravity, but weight kills fun.

3.9kg

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 millimeters 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

drove the car around and put 40 miles on it today... drove it through potholes and all sorts of bumps... even mashed the s*** out of it around some corners... all seems to be good now! no more rubbing on the lateral links!

Don't know if they're still available but I thought I'd post the link regardless. According to the currency converter it's about $551.36 + shipping.

AutoExe Chassis Braces

Front and rear braces as well. About $600 + shipping.

AutoExe Front and Rear Braces