Review: SADFab Delrin Bushing Kit
 

Before I start this review, I just want to make it clear that this is not an advertisement, and that sales of this kit don't benefit me in any way. I'm not part of SADFab and I purchased the kit on my own.


Intro:

To start things off, I've had Energy Suspension bushings in the car for years. I always thought they were great compared to the failing rubber bushings. When I first installed them, I could move the control arms with relative ease and the compliance was much less than the factory rubber bushings. But, after reading through The Bushing Megathread, I thought that some of the points brought up were valid and decided to go for one of the SADFab delrin kits.

I ordered the NASA legal kit which is a zero points modification in TT and PT, and I also added on the Front Lower Control Arm Offset Bushings in order to get stancenation levels of camber. The NASA kit does not include the rear upper outer spherical bearing portion of their normal full kit.

Here's what the kit came with:

- Delrin Bushings for the following locations:
- - FLCA Forward Bushing (Offset + Set Screws)
- - FUCA-I bushings
- - RLCA-I Forward Bushing
- - RLCA-O bushings
- - RUCA-I bushings

- Poly bushings and bronze bearings for the following locations (see Bushing Megathread to find out why):
- - FLCA Aft bushing
- - RLCA Aft bushing
- - RUCA-O bushing

- Grease fittings for all locations


Installation:

The first thing I noticed when taking the control arms off my car, was that I could not move them by hand anymore unless I put some serious force into it. To get the hub to move was probably 100+lbs of force to move them with the coilovers and sway bars disconnected. I did not have grease fittings installed, nor have I ever taken them apart to grease them, this is likely a huge contributing factor to that but whatever.

I took all the arms off, and headed over to Sean's place (hi_im_sean), who makes these kits. He has a press and was kind enough to help me get everything installed.

Next thing Sean and I noticed is that the bushing thrust faces were starting to chew themselves up, the sleeves had scoring on them, the plating had been worn off and the Energy Suspension grease had turned into almost an adhesive now that dirt and dust had been mixed in. A shop press was required to get most of them out.

After that, it's lots of cleaning, new grease, press bushings in, drill holes for grease zerks and for the offset set screws, etc etc. It's your typical bushing install aside from having to ream out the delrin bushings before putting in the sleeves. Everything was pretty straight forward.

After that was done, I just had to put all the arms back on the car, get an alignment and corner balance redone and hit the track. Luckily I had two track events on the same course, in about the same weather conditions only two weeks apart so I got to do some really good back to back comparison.

When the arms went back on, they move by hand with ease. The resistance is maybe 5% of what it was before with the poly bushings. Massive improvement.

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Observations:

TL;DR: I firmly believe this kit is worth purchasing and installing. I'm happy with my purchase and the results I've gotten with it.



First, I'm sure some of you are interested in how much front camber I was able to gain with the offset bushings. The answer is a lot. The middle of the adjustment range was about -3.5 degrees with 4.0" front and 4.25" rear pinch weld heights with brand new, zero heat cycle 205/50R15 Hoosier R7's on 15x9" Advanti S1's.

The adjustment range looks to be about -3.0 to -4.2 in the front at that ride height. Perfect for track oriented cars.

Qualitative Stuff:

-- The car is now fucking telepathic. It just feels much more connected to the road, and communicates through the steering wheel better.
-- The car now feels tighter and more solid.
-- It feels like the suspension is doing a better job now that it is not fighting the resistance of the poly bushings. Handled bumps and irregularities much better.
-- NVH did not really change for me, but my car is a purpose built race car and NVH is already abysmal, so take that with a grain of salt. Me personally, I would still not hesitate to put these on a street car.


Track Test Results:

Below, are pictures of two time sheets, before and after. The track is Wild Horse Pass East in Arizona. Those are the best laps out of each two day track event that I attended. The events were only two weeks apart. I'm usually a very consistent driver, the weather was nearly the same, and the car didn't have any massive changes.

Both events were done on Xida Gen 2 with Billet Coaxial Mounts.
Both events had no changes to power. The car makes 133WHP and 113WTQ on a dynojet.

Poly Bushings:
2405lbs coming off track
6 Heat Cycle 205/50R15 Hoosier R7
-- Alignment
-2.4 Front Camber
-3.0 Rear Camber
0 Toe All Around

Delrin Bushings:
2460lbs coming off track (+55lbs!)
0 Heat Cycle 205/50R15 Hoosier R7
-- Alignment
-4.0 Front Camber
-3.9 Rear Camber
0 Toe All Around

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As you can see, I went about 1.1 seconds faster with the SADFab delrin bushing kit. I also was able to break the long standing TTE record, set three years ago, by 1.3 seconds. The newer tires probably helped a bit, but take into consideration that during the faster run I was 55 pounds heavier as well. I had to ballast up a little bit for my new classing. Also, the way more aggressive alignment that I was able to achieve, as a direct result of the delrin bushing kit, helped a lot as well. Also being on a fresh corner balance and alignment was helpful too but I believe the delrin bushing kit played a large factor in being able to set that track record and my new personal best at that track.

Also, I've even got video from the two events. The first two videos are races from that weekend, I set the fast time in open qualifying that morning but no video of that. But the third video has the delrin fast lap in it.

Poly Bushings:



SADFab Delrin Bushings:




If you read this far, thank you. Hopefully this helps anyone looking for more information on this product. If anyone has any questions, feel free to ask and I'll try to answer as best I can. :party:


And a couple pictures from the Delrin weekend because why not.

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Nice review. These are on my list as well for my TT/PTE car. Good stuff.

Just received my delrin kit from Sean on Monday. High quality parts with better packing and labeling than the ES kit I bought for my 91. Super excited to install them next week!

I have a kit with the sphericals option waiting to go into my car. I'm excited to make the switch.

I also needed to press out my ES sleeves. It was insane how sticky the Hyperlube is and how high the stiction is. Hyperlube is now officially my least favorite substance. Cleaning my control arms was harder than fitting the SADfab Delrin bushings.

Good read, good to know I appear to have something to look forward to - heaven knows I need to find a second or two! Waiting on my delrins now, I upgraded from a poly bushing kit as they don't fit my Superpros.

That shit is nasty, im pretty sure its silicone based, so it already sucks to clean off. Degreasers just bead up on it, so you have to use a solvent, like brake clean. Aarons dad used gasoline with good results lol. Its also a dirt magnet worse than any "lube" I've ever encountered, due to its viscosity and sticky-ness. That shit will hold 1/4 minus landscaping rock to your bushings lmao.

Looking forward to buying this kit.

Not looking forward to cleaning everything.

I need to do this too. Superior product and supports a couple of good guys.

Arca, your videos need data!

Just FYI, when I put my polys in, I did grease fittings. Initial lube was done with commonly available marine grease and I've kept up with regreasing every 6 months. Hyperlube has never been near the car. After 2+ years of constant tracking, I haven't experienced the significant increase in resistance being reported here. I think the takeaway is -- when faced with the alternative of a "permanent" lubrication option vs. a continuous maintenance lubrication option, opt for the latter and make sure the lubricant you use isn't unobtanium.

FYI, I'm sure SADFab would be willing to trade fighter jet passenger time for delrin bushings...

If only my company owned a fighter jet! Our customers own those (and all the cool helos too).

Best I can do is a Beech Baron . . . it does pretty nice acro though:

https://www.miataturbo.net/attachmen...1&d=1459623600

I'll just buy a kit though. After all, you're the starving college student/entrepeneur with cool ideas and drive.

Great thread. I have been spending too much time lately thinking about poly vs. delrin vs. rubber. I am half way done with a hybrid Poly/Delrin setup and I am kinda wishing I had just left the stock rubber bushings in place or gone full delrin!!!

Also - just a friendly fabrication tip - when tapping things like mild steel or aluminum, I always just put the tap into the cordless drill and run it on low speed. Its 10X faster than hand tapping and you don't wallow out the threads as much because you can hold the drill steady and the tap spins true. This method always works great for me, unless the tap is dull, in which case you should buy a new tap! Just be cautious if you are using a small tap (m4 or smaller) or if you are tapping stainless.

Yeah hindsight is definitely 20/20 lol.

Also, data might be coming soon (Race Technology Dash 2 Pro) but if you've been following the build thread you can see where all of the racecar money is going...

Thanks man. Yeah these are quick enough anyways tapping by hand. For most stuff I like to be able to feel if it starts to get tough. Sean is the one that tapped all of these, so no issues there.

I made a quick video of the smooth action of the SADfab bushing kits on the car. Portrait mode for your viewing pleasure :)


RLCA-I: poly with bronze sleeve bearings
RLCA-O: delrin
RUCA-I: delrin
RUCA-O: spherical bearing

The bolts are all fully torqued, and there is absolutely zero play. The tapping noise is the RLCA bumping into the bottom of my damper. I "reamed" the delrin with a 7/8" drill bit until it had about the same resistance to rotation as a spherical in good condition. This is all before greasing the delrin bushings, but as you can see there is minimal friction. In the awkward camera position, the weight of the upright is quite a lot for me to lift (I am not a big guy), but I can still move it very easily with absolutely zero stick-slip.

For all of those who own ES bushings and use Hyperlube semi-regularly: if you are on the fence, go put your car on stands, disconnect the damper and sway bar, and try to replicate this video. Prepare to be frustrated.

Beyond the improved feel, can you conclude where you felt you gained speed in order to cut your time by almost a second on the track? Specific cornering conditions?

The specific cornering conditions where it seemed to help the most was when the track was bumpy (this one is bumpy in a lot of places). So anytime I was going over bumps during corner entry braking, mid corner, and trying to put power down coming out of corners seemed to be improved since the Xida's were allowed to work their magic much more effectively without having to overcome the stiction/breakaway force of the poly bushings.

The improved alignment (due to the offset bushings) and fresh corner balance also contributed to the faster time as well, but I feel that the bushings played a large role in going faster.

Did you install the bushings and Xidas at the same time?

Xidas were installed for both events, I think that's outlined in the track test section. Saw a significant improvement from them alone as well. :bigtu:

A delrin/spherical install dunnunda
 

Just finishing up my install, with rear knuckle spherical. Replaces a Superpro kit, been in the car since c2008/9.

The Superpros were a mixed bag, some pins seemed ok, others required hammering out. Some had seized and the whole bush was rotating, one rear knuckle was badly worn by this. As I couldn't in conscience sell them on, I ended up cutting the ends of a lot and punching them out. Any suggestions for what creative use these can be put to?

Just a couple of comments on the delrin, reaming was not as straightforward as I had hoped, just drilling didn't cut it (pardon the pun:rofl:) - that might have been my drill bit but the pins were a really tight fit, like hammer them in. Rocking the drill helped, but seemed to leave a bore that was wider at the ends than the middle. Getting the bores to a push fit I ended with a couple that are a bit on the loose side, I'll see how they go but they may need replacing.

Had a problem with the sphericals, a couple of details had eluded me and as a result one bearing was damaged and the sleeve scored. The sleeves were welded in, and this was done before the bearings arrived - Sean recommends the bearings be inserted before the sleeve is fixed. The welding left some residue obstructing the sleeve and that and the damage to the sleeve was cleaned up as best I could, including a bit of enlarging of that sleeve's bore to clean up the scoring. That worked so well the bearing sat inside the sleeve for a short distance, and then was pressed in. That initial positioning of the bearing made things quite simple, and I did the same to the undamaged sleeve. Note to those trying this at home, keep well away from the snap ring groove - if you are going to try this all you want to do is put a slight chamfer on the outer 5mm or so, just enough to get the bearing sitting inside the sleeve a fraction. It will require a few goes because you need to have the bearing properly aligned for insertion, not angled in any way. I was prepared to take a couple of risks because I have a spare spherical kit, and could start over immediately if necessary.

I did this at MX5 Solutions, and Dave made up a tool to seat the bearing, see photo. I might get him to make another to get the bearing out, unless tapping it out with a drift is possible without damaging the sleeve - opinions?

https://www.miataturbo.net/attachmen...ine=1462196287Install tool, with bearing sitting on it

Using this tool one bearing went in smoothly and easily. The other, the damaged/repaired pair, required more persuasion and the spherical action is quite stiff in comparison to the other. Again, I will see how it goes when fully assembled, but if it looks like being too stiff I will make up another upright using one of the sleeves from my spare kit, and a new bearing.

Next step is to get the head back on the engine (swallowed a screw/small bolt, dislodged SUB), get it aligned, and do a track test. I am particularly interested in any changes to the handling, and the possibility of changes to spring rate/shock valving that might be called for.

I had a similar issue to yours with the spherical. Spent about an hour with a pick and file cleaning out the snap ring groove where it had collapsed in.

Sean also made some tools to press in and out that helped me a lot. Though you are on the wrong side of the equator so shipping is probably really expensive.

Im starting to notice that welding either shrinks or distorts or both, the sleeve ID. This seems especially true when you full weld it 360 degrees on both ends. Ill see if I can add a lead in on all future sleeves to facilitate starting the bearing straight. Lost deep inside the spherical thread, I offered loaner press tools. These are still available if anyone needs em!

Although others have welded with 0 issues, I still recommenced the retaining compound.

This should be enough for a couple of cars

This should do at least one.
McMaster-Carr

Ive used 638. 640 and 680 should be acceptable as well.


Also, the bearing will, and should tighten up a little when you press it in. It will be difficult to move my hand, but should move when you stick a screwdriver or something with a little leverage through it. They will loosen up a little with use.

I used to weld a lot of these, for off road suspension. lots of cooling was key. I eventually made a brass slug that I slid into it while welding. controls the shape and draws out the heat. Had it laying around. Aluminum would work too. could be a cheap add on..

Aidan, What caused the groove to collapse? My initial efforts were always moderated by thinking about what a disaster it would be if I damaged that groove. That was a blessing as it turned out I was doing it all wrong.

The more I reflect on it, the more convinced I become that Dave's tool, and the chamfering of the bore, made all the difference. The unmolested set went together so smoothly it was as if they had practiced!

Yes postage is a bit of a killer, but small light stuff is ok. Having said that, the practicalities of sending stuff like that back and forth across the Pacific are a bit of a worry. We learn to make do!!

EDIT: Just seen Sean's post. It is possible that one of my sleeves was/is distorted. The other is ok judging by the ease it went together. Mine are 360 welded, both ends. Dave's tool would soak up some heat, if we had had it when the welding was being done, and had thought of using it for that ...

The 'good' sleeve has a loose bearing, just like it was before being installed; the other is as you describe Sean, firm/tight, moveable with a screwdriver.

Freezing that bearing for a couple hours would probably help a lot too. Along with the aluminum insert tool.

Got my bearing in and sleeves are held in with the Loctite sleeve juice.
Though I had to rubber band them from sliding out under gravity. They seem pretty locked in there now but it was a little questionable at first.

Hopefully sometime in June I'll be installing them. I have't had a free weekend for a month+

Yea, I walked away from mine right after gluing and they had almost slid out lol. I used a clamp overnight.

https://www.miataturbo.net/attachmen...ine=1462207002



Ryans tips are great, I suggest they are followed. I can make a heat sink slug/weld spatter guard thing for those that are welding them, just ask.

Edit: Accidental post

Thank you for the reviews everyone. We are now a supporting vendor so contact us for any information you need about bushing kits.

Props for officialness.

Dang. Millenials doing the entrepeneur thing. Must make Bernie proud to see future massive taxpayers in the making.

How do I order a bushing kit? Just make a PayPal donation for the correct amount with a note? Send an E-mail?

PM or email at info@sadfab.com. No phone number yet :)

carrier pigeons with gold coins

they don't have phones.....yet....must sell moar kits

Done!

These look tempting. It's great to have more options.

Def interested in a set of these for my car

I would certainly be interested to hear someones feedback on using these in a street car. I do have some compromises to NVH already, but overall my car is a very comfortable street car. I would love the increased feedback but I assume inherently this would come with more NVH.

We are waiting for @thumpetto007 to install them on his NB. As far as I know everyone else that has installed them has done so on a race car.

Would like to give you feedback, but my miata sees less and less off-track time than ever anymore.

On track they're fantastic through. Drove my car (poly kit) back to back with Aidan's, and the difference was very clear.

Ryan taps his fingers, waiting for a set.

Installation is finished, no real issues, zirk? fittings too.

Transmission finished up today in North Carolina, so it shouldn't be more than 2 weeks from now where I have the first drive. I'll be sure to post my own review thread.

I'll have an additional perspective as well. I have a female (gasp) that has ridden in the miata often, before bushing, trans, and billet top mount installation. She is very sensitive to NVH, and general ride dynamics, as she gets car sick easily. This will help with a more real world opinion.

Good. Because my girlfriend falls asleep in my rattle trap. So she is no good for reviews.

For some that could be a valid data point

I think its more of a data point on my girlfriend.

She likes the ultrashield aluminum seats "because they hold her in, and the there are headrests (aka shoulder supports)"

Delrin bushings did nothing to make my car worse, I don't know how they would do on a car that isn't already a rattle trap.

Been a while, too long in fact. Because Reasons, had the car on the track yesterday for the first time in about 15 months. Basically a shakedown, but some observations.

At SMPGP, I hop a couple of kerbs. Where there was a bit of thumping before, this time there was a definite rattle sound. All looked ok, but the car will go on a hoist for a check out.

Times were good, on old rubber (AO50/M compound). The fast T1 was faster than a full aero equipped MX5 that I was in company with, even though I was running naked aero-wise (don't ask). Overall, about a tenth off the previous outing on that track. Subjectively, hard to say, given that this car is much rawer than the road MX5 that I competed with last year, which had me spending quite a bit of time playing myself back in. However even at this stage it felt good, very responsive. A little early to tell whether spring/shocks will need changes as a result of the freer movement, I am happy to let that emerge (or not, as the case may be) over future outings.

Spent quite a bit of time reading many of the threads on delrin bushings as my NB upper rears are shot to the point they are clunking and car is tramlining.

Love the full delrin on my C6Z, and was ready with a press to install.

Then I tried to order a set, 5 week backorder and a weekend at Sebring scheduled in 4 weeks :vash:

Quick update, The guys were nice enough to send me just the in stock rear upper bushings so I could fix before Sebring.:bigtu:
What bushings do you think clunk less and have better feel in corners?
Old bushings came out with just a piece of pipe a socket and vise.
https://cimg3.ibsrv.net/gimg/www.mia...aa69108260.jpghttps://cimg4.ibsrv.net/gimg/www.mia...5c2a3cfe5d.jpg

I was able to push my RUCAs out by hand, they looked like yours.

My bushings that arrived last week are made from black delrin vs the white you have been using for a while?
In the past I have noted black plastics tend to have slightly better strength than white due to the needed mixtures? Is this the case?
Is there a material strength difference, or is it just cosmetic?
Looking fwd to the rest of the kit.

My RUCA-I's look the same... really need to get the Delrin installed

My kit from Sean is stuck at the post office... sadly, its awaiting a signature confirmation and I'm never home during delivery or post office hours.. let the games of figuring out how to get my package begin!

Could you go to the PO at lunch?

If I could, I would. I live 45 mins from where I work.

We've been using black for a while, because once you go black.... most people prefer it.
The spec sheets do not differentiate between natural and black, so I'm lead to believe there is no difference, or it is negligible.

Really nice review here. I haven't gotten a chance to install mine yet but this is making me really anxious to do so.

If you're coming from stock, you're gonna love it. If you're coming from shitty sticky poly bushings, take a towel with you.

Yeah, these poly bushings look really gross. I'm not excited for the work, just the end product.

If you have a press its not horrible. But without one it can really suck.

That's not exactly what I meant... I was referring to your physiological response when you drive it afterwards...

Cool, a press will certainly be used.

Ah, got it. Can't wait.

I have had my bushings in for about a year now. I got the NASA full enchilada. This is an auto-x car that gets driven to events and occasionally for mental health reasons. So about 4000 miles and maybe 160 auto-x runs. Car is on 275 A7's, weighs 2050 in race trim, 130wtq and 150whp from VVT engine, and ARE Penskes with spherical tophats are the relevant bits.

The sadfab kit replaced a poly kit from Prothane that had been on the car for about three years. Now I know everyone hates poly on here but my personal experience with the kit I installed was quite positive. I never had squeaks or clunks, or a broken bushing, or a binding bushing after three years and never taking them out to relube. But I got the sadfab kit anyhow as it was just a logical better choice and three years is just too long for poly.

After installing the sadfab kit I had to make a minor shock setting as the car felt a little loose. The bushing change also accompanied a front suspension swap to NB parts which netted about .3* less camber and +2* more caster. And possibly I could have driven around the looseness but the adjustment seemed to do the trick and I never went back to the other setting in this years time. Since this is an auto-x car I don't have any data for comparison that would prove one is better than the other plus also the NB parts would likely skew the results. For street driving there was also no negligible difference with the added stiffness of Delrin for me but since the car rides on extreme summer tires and 800/400 springs the level of comfort I have gotten used to might differ those who would notice rubber over poly over delrin.

Just recently they front lowers were out to address a knocking from the front suspension. The bushings (both the delrin and the poly) had squished a bit which allowed the bearings (sleeves) to be a touch too big. A quick trip to a lathe to take out a mil from each front and back bearing and all is good again. The only other gripe I had with these was on install the RLCA-O bushings had to be filed down quite a bit to fit. Then again, it's better to have the bushings too big than too small. Can't stretch the bushings after all.

Overall I definitely recommend these to anyone who is serious about their suspension.

I have addressed the RLCA-O issue as you were not the only one to have that problem with some of the early kits. Theyre still tight for the reasons you mention, but you shouldn't have to remove any material any longer. That one is a pain to get right as there is a huge difference in the dimension between bushing bores across different arms. At least the rear knuckle is fly cut across the sides and that dimension is very consistent in my experience.