Front or Rear strut bar

Gro Harlem · Post by **Gro Harlem** » June 3rd, 2005, 5:03 am

negatory.

rear would b/c of the 60/40 weight distribution, FWD, and heavy placement of the V6 in the GS.

You want to negate the horrible understeer as much as possible. This means stiffening up the rear and getting a thicker rear swaybar.

Front would make it understeer MORE.

But obviously both F&R would be ideal. But if you are going to install only one...go with the rear first.

RaverChankoMX3 · Post by **RaverChankoMX3** » June 3rd, 2005, 6:54 am

Gro

When you were AXing, you didn't notice our car doesn't seem to have the "horrible understeering" problem most FWD cars have? I wouldn't do either one first, I'd do them both. You can wait and save up another what, 80 more bucks and just do both at the same time.

snellgrove · Post by **snellgrove** » June 3rd, 2005, 5:43 pm

yeah anyone got pics of their rear strut-brace install?

I want one for mine, just because.. :p

it has one in the front as standard, which definately helps with cornering! really nicely.. but I want to strengthen up that rear if I can..

looking at the corksport, and racingmazda sites now

Gro Harlem · Post by **Gro Harlem** » June 4th, 2005, 5:18 am

OMG the hell it doesn't! I dunno what you have done to your car, but before I did much to my suspension it understeered pretty friggin badly.

It still does quite a bit but those adjustable endlinks and suspension bushings I installed removed some of the slop in my rear suspension, and my new strut/spring combo is pretty much ideal.

it still likes to plow ahead under heavy cornering though

Nd4SpdSe · Post by **Nd4SpdSe** » June 5th, 2005, 12:43 pm

I hate to argue against you Gro (especially your knowledge plus you've AutoX'd. Don't be affraid to correcty anything I say is wrong, what I'm explaining is best to my personal experience), but I have a hard time believing that the rear bar is more beneficial than the front. Personally, I ran both just the front, just the rear and both, and my experience is that the front gave a HUGE improvement on handling than the rear. The front-only was on for several weeks until I had the time to modify the rear seatbelt mounts and interior pannels to accododate the rear, i had the rear only for several months since I didn't figure out how to mount the front one back on after the ZE swap, and I have both front and rear on how for over a year.

Mind you, this is with the stock suspension; with the lack of front strut bar, the car felt nose heavy, where the weight would want to transfer to the outter front tire, inducing the dreaded understeer symptomes symbolic of front-engine, front wheel drive vehicles, along with a fair amout of body roll. The front strut bar stiffened the front end, largely reducing the feel of the car wanting to transfer weight to the outter front tire, allowing me to corner faster (alot less, or no tire squeel), and improving steering responce. The rear added later gave little improvement, giving a marginally improvement in corning speed, but responce and feel stayed mostly the same. The benchmark corner I used were 3 30km/h merge ramps I used daily coming home from work.

During my ZE swap, my front bar was removed, and I missed it, the front felt sluggish and front heavy again. That winter, I did notice it being oversteer happy taking those same ramps when snowcovered, the rear came loose on two occasions. My theory on it is that the stiffened up rear end caused the rear tires to break traction sooner than the front, but this oversteer was only noticed in the winter.

What I don't understand is how a stiffer rear will reduce understeer (and again, correct me if I'm wrong), but won't a stiffer rear create understeer? The way I look at this is if you have a stiff rear and a loose front, the front will always want to plow into the turns and understeer, and with the rear being stiff, it hold the road more than the front, so the front will give way sooner, however if you had a stiff front and a loose rear, the front will hold and corner tigher and quicker, but the rear loose will want to come loose, potentially creating oversteer. Ideally you want to find a balance of course.

Now I know you've autocrossed before (and I havent) so you've pushed your car to the limit, and maybe at this limit is where you see it's benefit, and it may come down to driving style as well, but myself, I found the front much more beneficial than the rear.

Gro Harlem · Post by **Gro Harlem** » June 5th, 2005, 2:58 pm

well i'm not an engineer so I can't and won't explain in super detail why stiffening the rear on a FWD car reduces understeer, but either way, STB's WILL NOT affect the handling limits of the car much, if at all.

Swaybars are what will really transform the feel and handling limits of your car. Getting new energy suspension frame-mount bushings for your bars (to replace the rotted rubber ones), and making some adjustable endlinks for the F&R alone will bring your swaybars back alive.

On top of that, getting the whiteline 22mm rear bar to replace the stock 20mm will help reduce understeer.

I'm waiting for my buddy on the clubprotege board who goes by several monikers (clubprotege, mazdaspeedwest, darryl, MazdaRacer) who is doing a KL swap into his protege LX for SM class. He developed some F&R tie-bars for the protege/escorts that also fit the MX3's. He said he is going to make a custom ONCE PEICE front strut tower bar that should be way better than the s--- they sell on ebay.

I'm just waiting for it to be developed & come out. I'm sure it won't be cheap but its performance will likely be better than anything else on the market. I'd guesstimate that it'll cost 100-130.

neutral · Post by **neutral** » June 5th, 2005, 2:59 pm

Nd4SpdSe wrote:...Personally, I ran both just the front, just the rear and both, and my experience is that the front gave a HUGE improvement on handling than the rear... with the lack of front strut bar, the car felt nose heavy, where the weight would want to transfer to the outter front tire... but myself, I found the front much more beneficial than the rear.

Same here but that does make sense right? Gro's written on this before but I just don't see it cuz the cornering forces are gonna be greatest against the front suspension and unibody, given the 63-65% of the car's weight up there. + w/the front wheels doing all the turning, that weight and inertia effect is amplified by the change in steering direction. Rear of the car is just following. The rear is under some body roll stress but significantly less than the front end IMHO. That's why the benefit of the strut brace is noticeable most on a front-only install. .02

Gro Harlem · Post by **Gro Harlem** » June 5th, 2005, 7:00 pm

put it this way....lemme make up a scenario for you to fully understand why stiffening the front of a FWD car = understeer:

Imagine if you took your stock MX3 with stock suspension and welded some thick-as-hell tubing across the top of the struts, across both fenderwalls, and across the bottom basically making the front rigid as hell.

Now lets say the rear is completely stock, no stiffening done.

If you push teh limits while cornering your outside wheel will be fully loaded while your inside wheel will lift damn near off the ground. Why? B/c of how damn stiff the front of the car is.

Having one tire contacing the ground while turning, while the other isn't even touching the ground means the front of the car which is both steering the car and powering it, won't do what you want it to. The tires will be less effective, thus not turning as much as you wish it to turn which is the definition of understeer.

And take this scenario for the rear and the rear wheel will lift off the ground under extreme cornering. I'm sure most people here have seen photos of VW's, civic's and possibly jesse's old protege LX w/only 3 wheels on the ground. I have a vid of my MX3 3-wheeling once but its pretty shitty quality. It was back when my car was still titanium color.

Gro Harlem · Post by **Gro Harlem** » June 5th, 2005, 7:08 pm

Oh yah I should probably add in to that scenario a bit.

Since you are running stock suspension...the springs/struts will have a LOT of travel since they are softer.

Obviously if you are going to stiffen the living hell out of your front & rear, you should definitely get stiffer springs. TO help ppl understand why this is just think about it for a sec.

Under extreme cornering you are transferring a hella lot of weight to one side of the car. If the springs are the stock softies they will compress MUCH MORE than a stiffer lowering spring meaning the geometry of the entire chassis will be even more at an angle (thus lifting the inside tires).

So if chassis is stiff and complimented with stiff springs/struts the inside tires won't lift as much meaning less (and in some cases no) understeer.

Drive a Integra Type-R or Mazda MP3 or Mazdaspeed Protege to their limits and you'll understand

Those 3 cars are pretty much set up neutrally from the factory (meaning no understeer no oversteer, perfect suspension balance).

Nd4SpdSe · Post by **Nd4SpdSe** » June 5th, 2005, 7:59 pm

Gro Harlem wrote:If you push teh limits while cornering your inside wheel will be fully loaded while your outside wheel will lift damn near off the ground. Why? B/c of how damn stiff the front of the car is.

Don't you mean the other way around? The inside tire will be off the ground and the outside will be fully loaded? Are you talking about the rear or the front?

Gro Harlem · Post by **Gro Harlem** » June 5th, 2005, 9:02 pm

oops i got that all backwards, i edited the post lol.

and yea i'm talkin about the front.

see on that vw how the rear is off the gnd and front still on the gnd...thats a better scenario than the front off the ground and the rear touching don't ya think?

Nd4SpdSe · Post by **Nd4SpdSe** » June 5th, 2005, 9:27 pm

So it is an "at the limit" thing....

Makes complete sence now!

In essence:
-If you plan on improving your daily driving experience: Front
-For competitions or your just a really insanly crazy driver and I would pity your car if you put it through this daily: Rear

projectmx · Post by **projectmx** » June 6th, 2005, 12:09 am

just like to say thanks for all this awesome info.. i'm really glad i asked this