Hi
I am constantly researching and planning whats going to be the next "project" on my FD. For a ling time i have put of buying new wheels, but next season its finally become a priority.
Problem is. RPF1 have thin spokes. Thin spokes make the suspension visible. My suspension looks dirty and is full or underseal.

So i will take it apart, clean, mediablast and then paint all the aluminium parts.

While doing that, i will also refresh the stock 26 year old suspensions bushings. The plan was for a while to go with part Poly and part stock rubber, but i have changed my mind and think i will go full rubber.
The question remains tho:

Regular stock or the 40% stiffer Competition/Mazdaspeed.

Key points in my decision making:

• I am only using the car on the street, no track use.
• Currently running lowering springs, but will go with Öhlins in the end. Either regular the Sakebomb specials.
• Stock engine currently, will upgrade it but probably twins. I cant imagine going over 450rwhp.
• I _hate_ noise vibration and harshness.
• The $500 difference in price from regular to competition is not a deciding factor.
• I will probably run with the Mazdaspeed/competition bushings for the diff and engine mounts
• They are called "Competition" and thus they must be better than regular ones right? (joke, but with some truth)

Does anyone have any experience, input, thoughts or have had similar qualms when having to decide, or am i just massively overthinking

 

I had simular thoughts when I was planning my bushing replacement, but decided to go for a poly kit (SuperPro, comes with steering rack bushings that didn't need modification) with Banzai Street Poly diff mounts, Banzai Street Poly Engine mounts, J-Auto PillowBall Kit and Mazda Comp Rear Lower Control Arm inners. It doesn't seem noisy or harsh, just nice and tight.

If you're looking to clean up the control arms, I was considering painting mine as well, but some hot water, dish soap and scotch brite pads made such a difference I decided not to paint them.

 

I think the answers you get may vary greatly depending on folks' sensitivity to NVH. I switched my diff and engine mounts to poly and I personally regret it, but I'm also fairly sensitive to NVH. What you might do is pick and choose what to put where. Mazdacomp for suspension, normal Mazda for engine and diff. That's the route I plan on taking later on. For the record I have not tried any Mazdacomp bushings yet, so in for info as well.

 

Re: Differential bushings....

https://www.rx7club.com/3rd-generati...hings-1128159/

Post# 28 gives feedback

 

How does your car feel? If you feel like you want to tighten it up, then tighten it up, but if it feels ok, the don't mess with it

And I wouldn't go any tighter than Mazda comps if you change things up

 

Sounds like stock might be the right choice

 

This re: engine mounts.

The change to poly for mounts makes shifting feel great. But I had to raise idle speed with AC or fans running because my interior felt like it was gonna shake apart.

I own the Mazdacomp mounts for suspension and they’re great. They’re just much more expensive and more difficult to install. I was mulling over poly for bushing or the Mazda ones for a long time. I think if I were to do it again, I might go with poly because the price point is so much lower and I think there is less noise translation through the suspension arms than through engine mounts. You can get a complete poly kit for almost half the cost of full OEM. Poly would be a lot easier to install too.

Matt

 

OPINION.......for street find low mileage (under 80K) suspension arms and save time & money.

 

Forgot to mention.....low mileage STOCK suspension arms with good ball joints and pillow ***** usually have perfectly good bushings.
Like these on post #32
https://www.rx7club.com/3rd-generati...1146410/page2/

 

I have the full Mazdaspeed bushing set on my car (control arm bushings [14 bushings plus 4 rubber spacers], anti-roll bar bushings [plus bars], shock mounts, trailing arm bushings, differential bushings, and motor mounts). Paired with GAB Super R shocks and H&R springs. Car is street driven only

Tightens the car very nicely but does not make it harsh. Slightly more NVH but still well within the realm of a street car.

I did this 10 years ago when prices were not too crazy (and I got a deal on the motor mounts, which are now ~$800 for the pair). It could be an expensive proposition now.

 

Any kind of increased stiffness will not do well on rough roads. Try having fun on a cracked, beat up twisty back road when you have stiff suspension that was meant for nice smooth, well maintained roads. More compliant suspension components will soak up the rough pavement and be not stable and confident.

The better the roads are the less trade off you have. Where I live now we have harsh winters and poorly funded roads, and any kind of stiffened suspension does not handle the bad pavement. So I stick to less stiff suspensions. Where I used to live we had mild winters and well maintained roads, and you could use competition style suspension and hardly notice a difference.

 

Of course a stiff/harsh ride was a criticism of the car when new. So it was (apparently) never fun to drive on bad roads. Drivetrain nvh maybe another question.

 

Thanks for all the replies!

To give some more info:
- I currently have around 40.000 miles on the car. I am pretty sure the bushings and everything in the suspension is factory originals.
- I need to change out the pillow ***** anyway since one is shot and clunking.
- Suspension bushings are the only rubber left on the car that's older than 5 years, so they are getting swapped no matter what.

I was/am experiencing shifter movement on acceleration/ deceleration, so i tried some stuff to remedy that.
- I am running PowerFlex on the diff and trailing arm. I have PowerFlex ready to go on swaybars and steering rack, but i am not sure if they will be used.
- Currently stock engine mounts but i have a set of Banzai street poly that i never got around to mount. not sure that i ever will.
- I tried the transmission brace from Banzai but i removed it after a week due to noise and vibrations (it is said to not make much NVH so there is your benchmark )


My main concern is how stock vs comp affect my planned Ohlins suspension. Bad move to drop 3k in coilovers and then have it be **** due to squishy bushings.
Also, for diff/engine my concern is shifter movement and wheel hop that one time per year i try a burnout or the occasional spirited roundabout.

 

As far as the Ohlins go, I've got the basic (as in, not the FP spec etc.) DFV kit on stock bushings and I love them. I'm no hardcore track guy so maybe your standards are higher, but I find it hard to imagine that stock bushings would reduce their performance to "****". One thing you might do is install them on the car with your current bushings and then see if you feel the car still needs more suspension rigidity. If you're already planning on installing them anyways, it'll just cost you some time.

Not sure how many other options there are regarding shifter movement besides engine mounts. Engine torque dampener maybe? I thought these used to be more popular but I have no idea if they're any good. Are your current engine mounts as old as the rest of the bushings? I wonder if a new set would tighten things up just enough...

 

sounds like you've already gone down the stiffer suspension route. I'd get the competition bushings.

engine mount NVH is subjective. To me the stock ones are actually really rough (compared to a modern car) and the street aftermarket mounts I've used are even more rough.

 

So, i decided to dig out my EPC and have a look at the bushings, to compare prices. I found two things:

• The price difference between OEM and Competition is only $273 when doing every bushing front and rear.
• You cant buy the OEM Trailing arm bushing, it comes with the entire trailing arm. So that will be Competition no matter what.

 

Do a couple autocrosses and get a Mazda comp account. Should save some $s
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The mazda competition bushings are slightly noticeable but not nearly as drastic as the poly bushings. It's not a huge difference. I didn't like the poly for street driving. Too much nvh. I might consider poly or the aftermarket heim joint bushings for the rear trailing arm.
you'll notice the change to Ohlins a lot more than the bushings