When and Where to use poly or delrin suspension bushings? - MK1 GTI

Hi everyone,

So I’m seeking some advice on WHEN and WHERE to utilize polyurethane or delrin bushings. To put it in perspective I don’t want to wholesale replace EVERYTHING with poly and put myself in a position where it negatively effects the handling characteristics of the car and/or likely puts me in a position where I’m a year or two away from having to replace them because they are squeaking like crazy or are making my handling unpredictable.

I have an 84 VW Rabbit GTI and I want to go through all of the suspension bushings this winter. So I’m looking to you guys for experience and advice because you’re much more aligned with a performance mindset then the mixed crowd of vwvortex contributors who fall into 1 of 3 camps. 1) restoration purists 2) Stance whores or 3) All out track guys. Frankly finding opinions from the No. 3 people is hard to gather too. There’s an “all or nothing” mentality that prevails as well. I need to “wade into the water slowly” here. Being that this is a BONE STOCK car it’s a blessing and a curse. I feel like I’m going to keep this sucker for a long time, but I need to exhibit some common sense with building it up too. We’d all love to throw $3K into coilovers if we could, but my main concern this winter is to rehab it enough to make it enjoyable and “beat on it” a bit. Between knowing it was old and unmolested and needing a gas tank since I bought it in June I never really got a chance to “flog it” on an autocross course either. So I want to get it up to a standard of maintenance that I can really push its limits. I WILL continue to make equipment upgrades, but the first step is at least enjoying driving it with some wreckless abandon and knowing what I need to upgrade next.

For Reference, he’s a link to a website selling poly bushings that has a diagram of the rabbit suspension bushings:

suspension bushing diagram

So with that being said I’m looking for some advice on WHERE and WHY I should put poly or Delrin bushings?

Where would it be wise to keep OEM replacement rubber?

Can anyone speak to their LONG TERM experiences with poly or delrin? It seems as if from what I have read poly is either perfectly fine and nothing to worry about over the long term if you grease it properly the first time, or the devil incarnate because it squeaks like crazy and ultimately turns to dust in 1.5 – 2 years on the worst case scenario.

I’ve seen some opinions on the vortex that Lower Control Arm bushings (keep in mind MK1s have McPherson sturts) and Rear Beam Bushings (main contact point between the rear beam and body) are good places to use delrin. Can anyone confirm or disagree with this?

How about Poly on steering rack bushings? Does this “tighten up” steering responsiveness?

What do you think of poly or delrin on the rear beam bushings? These cars have more of a trailing arm style mounting point. I have heard that on MK2s and MK3s poly bushings can create some unpredictable handling in the rear, but most of the opinions on the MK1 is that it doesn’t cause the same issue. I’d like to hear what you guys think from a motorsport opinion though.

Any advice would be greatly appreciated. There's Black Friday sales for bushings on a couple of sites right now until Monday so I will probably be placing an order soon.

I don't know the specifics of a GTI but from my understanding the only place you wouldn't want to change from rubber is if the part needs to move in two directions at the same time so as not to bind the suspension. Think about the upper links on a solid axle with a four link.

Outside of that the only real downside would be NVH.

I put poly steering rack mounts on the E21 and it made a wonderful difference. Again I'm not sure how a GTI is put together.

if the LCAs of the GTI are set up anything like those on a R53 mini, definitely either poly or delrin the bushings at the rear of the control arms, at least on the Mini, when those bushings deflect under hard braking or acceleration, it causes measurable alignment changes which really don't help tire wear or traction or feel. definitely poly (delrin would be even better) the steering rack bushings, all that will do is keep the steering rack from moving around under load, which can only help steering precision/feel, and I can't imagine it would hurt anything either

Poly on the anti-sway bar bushings can increase the effective sway bar stiffness somewhat, which may or may not be desireable for your handling.

Poly or delrin are both fine on the mk1 control arms. Mk2+ dont use poly in the rear spot due to binding issues

I've got an '84 MK1 GTI. No where near as pretty as yours.

I've learned a few things about them.

You've told us lots about internet theory (good research, BTW), and very little about your needs, goals, and experience, so I am going to read between the lines a little.

• Every rubber component on your 30 year old suspension is worn out, even though it is a low mileage vehicle. They'd be worn out if the car had zero miles on it. The rubber breaks down, and is simply not as resilient as it once was. So, OEM bits will give you excellent returns.

• However, GTI performance parts are really cheap. Why not change to a performance part (Delrin or other), when the cost is minimal?

• You didn't tell us if you are capable with a wrench. This will make a really big difference in the cost. It's a super cheap car to work on if you know how. It is a quirky old car that can't be diagnosed with a computer if you have to hire a mechanic.

• I am getting the sense that you do not have a huge amount of track seat time under your belt. If this is the case, you won't feel the difference between the Delrin and the rubber in most locations. You WILL feel the difference between anything new and the old stuff you have.

• That car has some really weak points, which will make a much more noticeable difference than poly bushings. The chassis horns that support the front suspension are really weak, and it responds really well to a lower strut bar. I made my own for less than $5 worth of scrap steel. After that, I'd go for an upper front strut support bar, then a rear anti-sway bar. Then comes a rear upper strut bar. All of this can be bolted on without compromising the restoration potential of the car.

• When you start spending bigger money, the first thing is real rubber in a much wider profile and some lighter wheels. This will reduce the unsprung weight, and unleash a bit of juice with less rotational mass. I also like to go for a smaller overall diameter, to improve the final drive ratio off the line (but you will loose a little highway cruising gearing).

After replacing worn suspension rubber (with Delrin or OEM), new tires and wheels, and some basic reinforcing for the towers, by far the best thing you can do to improve the handling of the car is to tighten the loose nut behind the wheel. Seat time, seat time. When you can out-drive the car with those changes, and can feel the differences in minor changes (like tire pressures), you will be ready for coilovers, top mounts, camber plates, and the big league. Oh, and those coilovers should not cost you anywhere near $3K. Less than half that.

Nice car! Beautiful survivor. Welcome aboard.

As one who road races a Mk I chassis in the Scriocco Series II version I can say that yes poly will help if your bushings are OEM original but NEW OEM style rubber will also help just not quite as well. When I first built this car I did convert the front LCAs to poly and the rear axel beam bushings as well as the steering rack bushings. Currently I still have all of them except the front LCA forward bushing which has been converted to a all metal spherical bearing. You should also consider replacing all of your engine mount bushings with new OEM. The front mount is available in a HD version and a poly. I'd stay with rubber if this is a street car. They also make poly filler pieces that fill the voids in the right & left engine mounts. I did not use them as I just filled them with a 2 part liquid poly that I bought, mixed, and poured in. This is available in various levels of firmness.

For best handling you need a rear sway bar and no front bar. The OEM 16V Scriocco rear bar is more then enough if you plan on changing the springs as well.

Don't lower the car in front past having the LCA level. You can lower the rear more as the negative rake actually helps handling.

Steering rack bushings are the safest ones to convert to poly because nothing moves in them and they are under relatively little load - so you don't need to worry about squeaks and lubrication problems.

Other than that I can't help you, only poly bushings for my car come from an Aussie company and they aren't cheap even before shipping...

About the only think you don't want to change or make solid is the rear axle bushings. They're actually designed to flex a bit. When the inside rear wheel lifts in a corner, the outside rear wheel tows out causing a passive rear steer. If you change those bushings to solid or poly you'll lose that. In fact, unless they're broken, I wouldn't touch them. The looser they are without being sloppy, the more you're going to get the car to rotate.

The rear axle bushings actually cause a lateral load induced toe-IN, which compensates for the beam's flexing to a toe-out condition.

Now, I have heard of some autocrossers putting the rear beam bushings in backwards (or was it left-for-right?) so it enhances the toe-out under load rather than negates it...

There used to be a good wealth of info on A1 suspension setup on the Improved Touring forum. Not sure if this is still the case, it's been a few years since I've lurked there.

That's where I learned about the low rear setup. It worked wonders on my A2 chassis Golf. It looked a little goofy with stock ride height in the front and Neuspeed 2" lowering springs on the rear, but it helped corner exit grip to a phenomenal degree. Mostly it cuts down on chassis roll by getting the CG down. Stiffening the rear suspension, as any VW driver can tell you, only affects how high off the ground the inside rear tire is

Slyp_Dawg wrote: if the LCAs of the GTI are set up anything like those on a R53 mini, definitely either poly or delrin the bushings at the rear of the control arms, at least on the Mini, when those bushings deflect under hard braking or acceleration, it causes measurable alignment changes which really don't help tire wear or traction or feel. definitely poly (delrin would be even better) the steering rack bushings, all that will do is keep the steering rack from moving around under load, which can only help steering precision/feel, and I can't imagine it would hurt anything either

Thanks! Given that explanation I think I'm going to go Delrin on the LCAs then. I'm also going to order the Autotech Poly steering rack bushings.

SVreX wrote: I've got an '84 MK1 GTI. No where near as pretty as yours. I've learned a few things about them. You've told us lots about internet theory (good research, BTW), and very little about your needs, goals, and experience, so I am going to read between the lines a little. - Every rubber component on your 30 year old suspension is worn out, even though it is a low mileage vehicle. They'd be worn out if the car had zero miles on it. The rubber breaks down, and is simply not as resilient as it once was. So, OEM bits will give you excellent returns. - However, GTI performance parts are really cheap. Why not change to a performance part (Delrin or other), when the cost is minimal? - You didn't tell us if you are capable with a wrench. This will make a really big difference in the cost. It's a super cheap car to work on if you know how. It is a quirky old car that can't be diagnosed with a computer if you have to hire a mechanic. - I am getting the sense that you do not have a huge amount of track seat time under your belt. If this is the case, you won't feel the difference between the Delrin and the rubber in most locations. You WILL feel the difference between anything new and the old stuff you have. - That car has some really weak points, which will make a much more noticeable difference than poly bushings. The chassis horns that support the front suspension are really weak, and it responds really well to a lower strut bar. I made my own for less than $5 worth of scrap steel. After that, I'd go for an upper front strut support bar, then a rear anti-sway bar. Then comes a rear upper strut bar. All of this can be bolted on without compromising the restoration potential of the car. - When you start spending bigger money, the first thing is real rubber in a much wider profile and some lighter wheels. This will reduce the unsprung weight, and unleash a bit of juice with less rotational mass. I also like to go for a smaller overall diameter, to improve the final drive ratio off the line (but you will loose a little highway cruising gearing). After replacing worn suspension rubber (with Delrin or OEM), new tires and wheels, and some basic reinforcing for the towers, by far the best thing you can do to improve the handling of the car is to tighten the loose nut behind the wheel. Seat time, seat time. When you can out-drive the car with those changes, and can feel the differences in minor changes (like tire pressures), you will be ready for coilovers, top mounts, camber plates, and the big league. Oh, and those coilovers should not cost you anywhere near $3K. Less than half that. Nice car! Beautiful survivor. Welcome aboard.

Thanks for the thorough response!

To answer some of your questions and concerns I generally tend to be pretty mechanically inclined and for the most part if I can figure out what I need to do to repair something between a Bentley Manual or a DIY article I'll attempt to fix it myself as long as it doesn't entail something I could really screw up with my lack of experience like timing for instance.

I am to say the least rusty since it has been years since I've autocrossed, but I did put in a full season with a Chicago VW club when I had my 98 Jetta GLX VR6 and I attended the local SCCA school to start that season off. I plan on attending another local school this spring with the GTI and my general expectations for autocross are pretty low at this point. I don't see myself trying to be truly regionally or nationally competitive with the GTI and my real goal is just to have fun and enjoy driving the car.

I definitely want to replace all of the original rubber bushings on the car because like you said, regardless of the condition of the car right now everything on it is still 30 years old!

I am also planning on adding the front upper and lower strut bars and rear strut bar.

jimbbski wrote: As one who road races a Mk I chassis in the Scriocco Series II version I can say that yes poly will help if your bushings are OEM original but NEW OEM style rubber will also help just not quite as well. When I first built this car I did convert the front LCAs to poly and the rear axel beam bushings as well as the steering rack bushings. Currently I still have all of them except the front LCA forward bushing which has been converted to a all metal spherical bearing. You should also consider replacing all of your engine mount bushings with new OEM. The front mount is available in a HD version and a poly. I'd stay with rubber if this is a street car. They also make poly filler pieces that fill the voids in the right & left engine mounts. I did not use them as I just filled them with a 2 part liquid poly that I bought, mixed, and poured in. This is available in various levels of firmness. For best handling you need a rear sway bar and no front bar. The OEM 16V Scriocco rear bar is more then enough if you plan on changing the springs as well. Don't lower the car in front past having the LCA level. You can lower the rear more as the negative rake actually helps handling.

Thanks Jim. I appreciate your continued responses to my topics. I definitely value your opinions as an experienced MK1 driver.

I also want to replace the motor mounts as well as I can definitely see that those look shot! I'm planning on doing the HD OEM rubber mounts. I don't think it would kill me to go to Stage 1 BFI Poly mounts, but even having a combo of stage 1 and 0.50s on my MK3 Jetta GLX VR6 there were some days where I felt like I was going to loose a filling from the vibration at start up and I don't need that.

I'll probably try and post my questions on the No Front Sway Bar/Big Rear Sway Bar and front/rear spring rates in the near future as well. I'm leaning towards the Ground Control Coilover Sleves at this time.

Knurled wrote: That's where I learned about the low rear setup. It worked wonders on my A2 chassis Golf. It looked a little goofy with stock ride height in the front and Neuspeed 2" lowering springs on the rear, but it helped corner exit grip to a phenomenal degree. Mostly it cuts down on chassis roll by getting the CG down. Stiffening the rear suspension, as any VW driver can tell you, only affects how high off the ground the inside rear tire is

Interesting, and it definitely sounds like a good idea to have the rear of the car sitting lower if it gives you that much benefit. Since I'm planning on a GC coilover sleeve setup I'll have to try this out.

Between what you and Corey just said about the rear beam bushings I'm going to go with the Autotech Poly bushings. I'd honestly prefer to stick to OEM rubber on this but unfortunately they were only sold with the whole bracket and from what I've gathered from my research on vwvortex North America completely RAN OUT of them in late 2011 or early 2012. :( So that only leaves poly and delrin as options. I think the Autotechs will be good because they are supposed to be harder then stock of course but not as stiff as the Prourethane red bushings.

Contradiction wrote: I'd honestly prefer to stick to OEM rubber on this but unfortunately they were only sold with the whole bracket and from what I've gathered from my research on vwvortex North America completely RAN OUT of them in late 2011 or early 2012. :( So that only leaves poly and delrin as options. I think the Autotechs will be good because they are supposed to be harder then stock of course but not as stiff as the Prourethane red bushings.

Here you go.

http://www.mk1autohaus.com/Rear-Control-Arm-Bushing_p_6684.html

Knurled wrote:

Contradiction wrote: I'd honestly prefer to stick to OEM rubber on this but unfortunately they were only sold with the whole bracket and from what I've gathered from my research on vwvortex North America completely RAN OUT of them in late 2011 or early 2012. :( So that only leaves poly and delrin as options. I think the Autotechs will be good because they are supposed to be harder then stock of course but not as stiff as the Prourethane red bushings.

Here you go. http://www.mk1autohaus.com/Rear-Control-Arm-Bushing_p_6684.html

Those are actually just the rear control arm bushings not the rear beam like I'm looking for.

Never been a fan of delrin after listening to them on my friend's RX7 when they became very noisy. Never heard such a noisy bushing in my life.

I used poly on the front motor mount and LCA of my 84' Scirocco back in the day. Definitely noticed the increased NVH but they did increase handling precision. This was when I was in my early 20s.

I also used poly bushings in some locations of my FD. I wound up removing them. The NVH got annoying over time. I was in my late 30s on that car.

YMMV depending on your tastes and the roads you drive.

Another vote for poly rather than delrin if the car is to be driven on the street.

D'oh! You're right. I zeroed in on "rear" and it looked kinda like the right part.