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It was body roll combined with finding the limit on my current suspension setup.
now that I no the bad side of NO sway bar, I'll probably try it again on a more expectant basis, since the curve is 1 mile from my house, to confirm this isthe case.
next i''l get a sway bar and find out the downside of running with a sway bar and try and find a happy medium
I thought running a swaybar will make the rear end come around on you?
correct me if I am wrong, but that is what I expect (from previous reading) and will be looking for coming out of a corner getting on the gas hard.....
read that the car is not very forgiving when running a sway bar
It was body roll combined with finding the limit on my current suspension setup.
now that I no the bad side of NO sway bar, I'll probably try it again on a more expectant basis, since the curve is 1 mile from my house, to confirm this isthe case.
next i''l get a sway bar and find out the downside of running with a sway bar and try and find a happy medium
I thought running a swaybar will make the rear end come around on you?
correct me if I am wrong, but that is what I expect (from previous reading) and will be looking for coming out of a corner getting on the gas hard.....
read that the car is not very forgiving when running a sway bar
Running with no sway bar allows more roll and this moves the CG further over the outside tire, lifting the inside. This results in significant contact patch reduction and so it looses traction quickly which works great in tight autox courses where you can leverage boot leg turns and such. Add the sway bar and it reduces this to an extent. Now with the sway bar you may, depending on speed hit, some binding or the bump stops as the suspension bottoms out which can also cause some squirrelly action. Its really just a matter of being familiar with the car and how it handles. After driving mine for 30+ years it all seems normal to me. I'm sure it would be a rude surprise to my buddy with the corvette collection across the street.
This is why for autox folks run without the rear sway bar. Lets the rear end come around faster on corners but you have to expect it. Its nothing to do with binding, its how the car works. For high speed track or road driving a rear sway bar helps keep it planted on high speed sweepers like you hit.
This is opposite of what I know to be reality.
I have never used a rear sway bar in road racing on my RX7. I don't believe I have ever raced against or been been beaten by another FB RX7 with a rear sway bar. We just don't use them. The cars I am familiar with run really stiff front sway bars and really stiff front springs (500-700lbs in STU/E Production). In the rear, cars run spring rates from 200-275 with no rear bar. I will ask Jesse Prather when I see next and ask for sure. But my gut tells me he doesn't use a rear bar either.
I haven't autocrossed my RX7 allot but autox is something I have allot experience with in Mustangs - FOXs, S197s and S550s . Assuming that I have the desired about of front roll stiffness I can see where I might fit a bigger rear sway to help the car rotate in tight turns. However, in this scenario, removing a rear sway bar and or removing rear spring rate will not make a RWD car rotate better in a tight turn.
From my experience, overall roll stiffness should be addressed at the front of the car. This can be through stiffer springs and a larger front sway bar. Rear spring rates and maybe a rear sway bar are used to balance the car. For example, my RX7 has a 50-50 weight distribution with me in the car and full fuel cell. But front spring rates are twice as high as rear rates and I have a big front sway bar.
Personal preferences also come into play here. I want my RX7 to be neutral to tight. A loose race car makes it hard for me to be aggressive. Your mileage may vary
FWIW.... I have been told to run the rear sway bar...but not to connect it at the ends.. just the support bushings towards the middle..
I haven't disconnected mine as of yet...but I am soon to order a new RB front sway bar & I'll the the rear disconnected at the ends & see what happens.. I guess I'll try to report my findings, here.
FWIW.... I have been told to run the rear sway bar...but not to connect it at the ends.. just the support bushings towards the middle..
I haven't disconnected mine as of yet...but I am soon to order a new RB front sway bar & I'll the the rear disconnected at the ends & see what happens.. I guess I'll try to report my findings, here.
that is essentially running no sway bar. It is common to disconnect one end as a quick way to see what no sway bar feels like.
disconnecting both ends will result in both ends dragging on the ground.
you will know what i mean as soon as you stick your head under there for a look
Regarding rear shock. Mustang shocks for 79-2004 model years are popular options because you can get adjustable ones from Koni, Tokico, Viking, QA1 and KYB-AGX. Interestingly enough the shocks for 94-2004 are about an inch shorter than the ones for mustangs from 79-93. I have both (Koni Sports) and measured them. Could have sworn it was the other way around.... Now you know.
Hello,
are You saying that the rear shock absorbers from a mustang will bolt into a first gen Rx7?
thx,
Sam
Yes. I have used FOX body shocks (79-93 Mustang) and SN95/New Edge shocks (94-98/99-2004) on my race car as have others. Shocks for the SN95/New Edge are shorter. I have a set of double adjustable Konis that are going on next.
Do you have any pictures of your set up. Looking to get budget friendly adjustable shock/spring set up in the rear
Mustang shocks will fit using the OE Mazda mounts on the axle and the body. If memory serves, the Mustang shocks use 12mm hard ware on the bottom (just like Mazda) and the top mount fits the upper mount too.
My car is a race car and at the time the SCCA rule set I was building to didn't allow the spring to be moved from its original location. Which is fine because I didn't want to deal with the added cost of racing specific coil over shocks. Still don't. Go to: https://www.rx7club.com/build-thread...-992966/page4/ see post #86
Instead of coil over shocks, I put adjustable spring perches on the axle housing that accept 2.5" coil over springs. The upper mount was replaced with something I fabricated that will also accept the coil spring and give me a bump stop. I fabricated my own lower shock mounts and put them lower on the rear axle. I use 1/2" hardware and just drilled the shocks to make them work. In the photo you can see the mounts. The shocks are from PRO Shock and are a split valve non-adjustable stock car shock I used to run. Cheap and effective. I now run adjustable Konis
An alternative to this setup would be an adjuster that works with 5" coil springs so you can mess with ride heights. I used them when I was racing my car in its original class - Improved Touring. You should be able find them at a Circle Track web site like Speedway Motors or Pitstop USA. For springs the best bet was a 10" tall soft rate spring from Eibach cut in half. For example if you get a 100lb rate 10" tall spring and cut it in half you end up with two 200lb springs that won't coil bind.
My feeling about coil overs on the rear is that they are a bad idea because the upper shock mount is not designed for spring loads. If you look at how Mazda built these cars you can see allot of structure above the factory spring location and not much for the shocks. Shocks don't load the chassis that much. Springs do.
Last edited by mustanghammer; 11-05-18 at 10:43 PM.
Do you by chance have a picture of your fabricated top spring seat and bump stop? Is it possible to used the factory upper spring seat with the adjustable perch on the axel?
Do you by chance have a picture of your fabricated top spring seat and bump stop? Is it possible to used the factory upper spring seat with the adjustable perch on the axel?
You can do that, speedway motors has weld on ones and the respeed kits used a collar that sat on there I think. I personally just got 8" springs which lowered the car 3 inches or so. I would personally get a 10 inch tall maybe 200 lbs/in spring for street driving. I also have fox body shocks and they work great! The bottom mount is the tiniest bit woder but the shock mount is flexible enough to accomodate
Do you by chance have a picture of your fabricated top spring seat and bump stop? Is it possible to used the factory upper spring seat with the adjustable perch on the axel?
Post #13 shows the 5 inch adjuster that we have used in the past. It sets on top of the spring and also fits the OE upper spring mount. This image is from an E-production race car that has a 4 link rear suspension. Note that it also uses Mustang shocks. Something like this might work depending on the diameter of the sleeve https://pitstopusa.com/i-5066715-all...uster-nut.html
Post #35 shows the upper mounts that I fabricated. To install them I had to cut out the OE upper mount with a plasma cutter and then weld these in. The bump stop screws into the hole in the middle that has a 3/8" weld nut. I think the bump stop was actually a snubber from a traction bar that I found at an auto parts store.
I just recently installed adjustable rear spring perches similar to what Scott shows in his build thread. The threaded portion is a bit smaller than what he shows so I had to cut out the stock bump stop. I actually welded part of the bump stop into the adjuster to retain that feature. Without the bumpstop the lower spring perch was actually hitting the "frame rail" sometimes. Anyway this is the adjuster I used: https://www.speedwaymotors.com/Speed...cer,33328.html I trimmed down the barrel to allow about 1/4" to accomodate the not so cleanly cut off stock bump stop. Then welded the adjuster in place. As you can see in one of the pictures you have to be careful using an angle grinder with cutoff wheel in the confined space of the bump stop ;-). Scott's use of a plasma cutter is much preferred.
I have never used a rear sway bar in road racing on my RX7. I don't believe I have ever raced against or been been beaten by another FB RX7 with a rear sway bar. We just don't use them. The cars I am familiar with run really stiff front sway bars and really stiff front springs (500-700lbs in STU/E Production). In the rear, cars run spring rates from 200-275 with no rear bar. I will ask Jesse Prather when I see next and ask for sure. But my gut tells me he doesn't use a rear bar either.
I haven't autocrossed my RX7 allot but autox is something I have allot experience with in Mustangs - FOXs, S197s and S550s . Assuming that I have the desired about of front roll stiffness I can see where I might fit a bigger rear sway to help the car rotate in tight turns. However, in this scenario, removing a rear sway bar and or removing rear spring rate will not make a RWD car rotate better in a tight turn.
From my experience, overall roll stiffness should be addressed at the front of the car. This can be through stiffer springs and a larger front sway bar. Rear spring rates and maybe a rear sway bar are used to balance the car. For example, my RX7 has a 50-50 weight distribution with me in the car and full fuel cell. But front spring rates are twice as high as rear rates and I have a big front sway bar.
Personal preferences also come into play here. I want my RX7 to be neutral to tight. A loose race car makes it hard for me to be aggressive. Your mileage may vary
from reading this i would think i need softer rear springs. I have RB front and rear springs and a RB front swaybar. I gotta say though I DO NOT think a softer rear end (rear springs) would have helped diving into a corner. I think it would have made it worse. I think I need to look into my brake bias first when I get to it.
it's a 1980 with 2nd gen brakes front and rear, 5 lug conversion and a 2nd gen brake booster MC and metering block????? the splitter the lines go into.....pretty sure this is where I need to focus as well.
from reading this i would think i need softer rear springs. I have RB front and rear springs and a RB front swaybar. I gotta say though I DO NOT think a softer rear end (rear springs) would have helped diving into a corner. I think it would have made it worse. I think I need to look into my brake bias first when I get to it.
it's a 1980 with 2nd gen brakes front and rear, 5 lug conversion and a 2nd gen brake booster MC and metering block????? the splitter the lines go into.....pretty sure this is where I need to focus as well.
So from a braking standpoint you have an FC that is plumbed into 1980 lines including the 1980 factory proportioning valve? Are your rear brakes locking up when apply the brakes while diving into a corner?
Keep the following in mind:
Desired corner entry (meaning your ability to go as fast as you want and not crash/die/drive off the road, etc) is determined by the effectiveness of your brakes and the cars ability to manage weight transfer.
Springs, sway bars, etc come into play once you have entered the corner and are hunting down the apex and thinking about corner exit.
You are looking at your brakes but you also need to think about how your car manages weight transfer under braking. This is controlled by the shocks and struts you have on the car. This where having the ability to adjust compression and rebound in your shocks and struts matters. Front struts that allow the front of the car to compress too much/quickly combined with rear shocks that allow the rear of the car to rise too much/quickly under hard braking can lead to rear brake lock up.
From my experience, rear shocks are extremely important under hard braking. Case in point, I had a pair of Tokico Illumina rear shocks die in the middle of a race. This resulted in loosing all of the rebound control at the rear of the car. From that point forward the car was a total hand full under braking. Had to slow down to survive
Last edited by mustanghammer; 11-07-18 at 12:46 PM.
So from a braking standpoint you have an FC that is plumbed into 1980 lines including the 1980 factory proportioning valve? Are your rear brakes locking up when apply the brakes while diving into a corner?
Keep the following in mind:
Desired corner entry (meaning your ability to go as fast as you want and not crash/die/drive off the road, etc) is determined by the effectiveness of your brakes and the cars ability to manage weight transfer.
Springs, sway bars, etc come into play once you have entered the corner and are hunting down the apex and thinking about corner exit.
You are looking at your brakes but you also need to think about how your car manages weight transfer under braking. This is controlled by the shocks and struts you have on the car. This where having the ability to adjust compression and rebound in your shocks and struts matters. Front struts that allow the front of the car to compress too much/quickly combined with rear shocks that allow the rear of the car to rise too much/quickly under hard braking can lead to rear brake lock up.
From my experience, rear shocks are extremely important under hard braking. Case in point, I had a pair of Tokico Illumina rear shocks die in the middle of a race. This resulted in loosing all of the rebound control at the rear of the car. From that point forward the car was a total hand full under braking. Had to slow down to survive
It's a 2nd gen proportioning valve, and I plumbed all new brake lines. All new steering components and suspension linkages and/or bushings front and rear. None of the brakes locked up, They seem to work extremely well. Honestly, this wasn't about apex, corner entry or exit etc. I went in to hot, no doubt, was going way too fast, no speedometer and just shaking it down and getting on it. It was my fault the car got out of shape. I could hit that corner again and blow through it a hell of a lot faster on the next round with proper entry and braking.
Having a v-8 in front and empty gas tank probably didn't keep it from diving in any less, but it was the body roll that was "WTF, don't do that again" about it.
"This resulted in loosing all of the rebound control at the rear of the car. From that point forward the car was a total hand full under braking. Had to slow down to survive"
THAT ^^^
The shocks are KYB if I recall. I went stiff spring, soft shock. I'll add look into better rear shocks to my list :-)
Couple of thoughts. Pairing stiff springs with "soft" shocks doesn't really work. Shocks and Struts dampen spring movement and as spring rates increase the dampening ability of the Shock/Strut needs to improve. This is why aftermarket spring companies like to pair lowering/stiffer springs with premium shocks/struts in their kits. The OEMs do this too, look shocks/struts/springs for the current Mustang and you will see numerous spring/strut/shock pairings. An under-dampened car with stiff springs will tend to be bouncy and feel like it is more stiffly sprung than it really is.
So with a V8 the in front, you need some healthier front springs. Note that since this is where most of the weight of the car is, running stiff springs up front will not affect ride quality. Ride quality is most effected by the spring rates used at the back of the car...
I just recently installed adjustable rear spring perches similar to what Scott shows in his build thread. The threaded portion is a bit smaller than what he shows so I had to cut out the stock bump stop. I actually welded part of the bump stop into the adjuster to retain that feature. Without the bumpstop the lower spring perch was actually hitting the "frame rail" sometimes. Anyway this is the adjuster I used: https://www.speedwaymotors.com/Speed...cer,33328.html I trimmed down the barrel to allow about 1/4" to accomodate the not so cleanly cut off stock bump stop. Then welded the adjuster in place. As you can see in one of the pictures you have to be careful using an angle grinder with cutoff wheel in the confined space of the bump stop ;-). Scott's use of a plasma cutter is much preferred.
S0 I have a set of these left over from when I sold my Foxbody. Unlimited spring rate choices really. And easily found, also proven on and off the track.
https://www.rx7club.com/1st-generati...lower-1108117/ food for thought. i had this set up on my old rear - before i went coilovers with T3. eventually i'll do independent rear with a s13 set up i think... ugh, at some point. for the money this was good though
Anyone have a detailed list of the parts needed to build the rear coilovers? I have looked into it but I couldnt find the type of sleeves with the lower lock. Heres a picture of a set someone built:
this is mine.... I built my own rear setup mimicking the T3 setup... cost me half of buying... so far.. 2000 miles on them and working
10-24-18, 12:28 PM
