95R2-89TII Ground Zero

I have the cusco front under on my FC.....too bad I've never driven the car with it on.

slvr7

iTrader: (1)

I have a strut tower bar and a <homemade> under car bar (just like the mazdaspeed version).
Without either connected, I put a stripe of tape across the gap at the back of the drivers door, just above the beltline rub strip. Sliced the tape with an exacto knife. Put a floor jack under the rocker just behind the front wheel, and lifted the driver's front corner of the car a measured amount (8" I think). Popped the door open (to release from the latch), and measured the mis-alignment along the tape edge (3mm). Dropped the car back down.
Then attached the strut bar. Jacked and measured again. Down to 2mm.
Then installed the lower arm bar. Jacked and measured again - no difference.
Just my 2 cents.

ShadowX

Makes me wonder if this would be any better?



Although you'd think bracing the huge hole where the tranny goes would make some sort of a difference.

ddub

I thought about that one, but what ultimately changed my mind was the price

jon88se

I'm surprised to see nobody else with the Cusco rear bar and V-brace combo. Don't mind the filthy interior...I've gotta scrub the carpets back there.

ddub

Interesting, never seen that one before.

jon88se

The V portion is sold seperately from the rear bar...I had the rear brace for a while and added the V-section on. While the rear bar alone really helped the rear bite down mid-corner, the V-section did nothing.. It was inexpensive though, - I thought I'd try it out since nobody seemed to have it.

If you don't mind spending a few extra $ while getting Cusco's rear brace, it's a good piece if you wanna be a tad different Thankfully, we're Cusco's #1 US dealer so the price was right

88IntegraLS

Thanks for sharing, that is good information.

I once read a structural analysis papar on front strut bars on some BMW forum one day. There were free body diagrams and statics calculations and all. The article came to the conclusion that under cornering load, the front strut bar would be in tension, and it would be in compression when the car was sitting still or travelling straight. Using the bar as a tension member between the stut towers stabilized the front camber, though the amount of strain was not more than a _fraction_ of a degree.

Lower bars were not mentioned, nor were rear bars. I've always wondered just what they do, seeing as how the front control arm mounts are tied right into the firewall, while the rear strut towers do not set rear camber at all (that is done on the rear semi-control arms).

I really like the Mazdatrix triangulated front strut tower bar. I'm planning on fabbing one up for my FC one of these days.

88IntegraLS

Those look pretty functional. They address the rear cantilever of the transmission tunnel and eliminate a possible strain zone between the rear control arm mounts. The rear tri-braces might help too, although their purpose doesn't seem as intuitively obvious as the x brace.

Bukwild

yeah I already know that X brace won't fit for me. I have a 3 inch thunder fab DP/MP and their is now way that would fit under their. I might purchase the rear part to complete some of my suspension upgrades.

SureShot

I bet it's a big deal if you have a differential pinion shubber under there.
I expect that's what it's really for.

For even better turn in, relocate the battery to the passenger storage bin.

speedieFC

awsome work guys id like to know how those car really feel. im planning to do the same to mine in a couple weeks so i can out handle most rides around here. a stock 7 is pretty good but id like more control.
and dDUB i need one of those rotor oil filler caps thats sweet. and another thing i hope your going to put some more bolts in your waterpump pully.

jon88se

Already done, Optima red top hehe

West TX RX-7

Damn man you did an excellent job! Looks fantastic!

My bar goes in the holes to the inside of those bushings instead of around them. I think yours looks much stouter.

Travis R

Hey look at that, real data!
I suspect the lower arm bar doesn't do as much for a coule reasons:
1. The frame rails are pretty stout.
2. The engine is bolted in just a few inches in front of it.
It would be interesting to see what the measurement was with just the lower arm bar and no strut tower bar.
For the guys with the rear bar... Sorry but I don't think it's doing anything for you. There are no side loads going through the top of the mount, only vertical. The mounts would have to move an inch up/down before that bar would help hold anything together... at which point your windshield would shatter because your unibody is as soft as a wet noodle.

Rxmfn7

iTrader: (4)

As for why a rear strut bar helps out alot, I really have no clue. It wouldnt seem like there would be much stress at the top of the rear strut mounts. But... do a before/after drive with a good rear bar installed, and I can guarantee you will feel a difference. I know I sure did.

jon88se

I did too...as I said before, the rear had more bite mid-corner. The good thing about chassis bracing is that it can only help, it cannot hurt. I bet the difference with/without front and rear strut bars would be apparent on a track with lots of off camber sweeping turns.

On competition cars that take a LOT of cornering load from competition rubber, stiff suspensions and speed, I wonder if the bars help prevent chassis tweaking.

88IntegraLS

Well sure . . it is vertical stress due to the weight of the car. Lateral (cornering) stress is all in the rear subframe, not at the top of the towers like in front. A quick study of the rear suspension geometry will reveal why: the rear struts just damp the suspension and don't set camber angle.

MaxRX7

"tight"

ddub

The bolts that are removed aren't part of holding the pulley on, they were what held the clutch fan, if I'm remembering correctly, to the pulley but didn't go through all the way to hold the pulley on.

ddub

Thx, much appreciated

mycarisolderthanme

your tearing through your suspension upgrades, taking a much similar route that i plan to.

nice work!

ddub

Thank you much. Still haven't gotten around to the suspension bushings, but those (along with DTSS eliminators) come spring break in a mere 2 weeks