Hi all, I’m fairly new to the world of DAs (just bought a '92 RS) and have been doing a ton of research on the difference between the DA and DC front suspension. The tech geek in me loves it What I’d like to do is post my understanding, and hopefully I’ll get some comments on how accurate (or inaccurate) it is. Note this is all about the FRONT suspension only. The rear, as I read it, is the same, except for the shocks / springs.
DA has radius rods / traction bars. DC does not. You can buy a traction bar kit for DC that adds radius rods. DA traction bar kits are just upgrades over factory.
DC LCAs have no mounting points for DA factory radius rods. Thus DC LCAs can be mounted on DA, but you’d lose the factory radius rods.
DC has slightly different geometry than DA. DC upper arms, and the damper forks, are different. This is why front camber kits for the DC are plentiful, but camber kits for the DA aren’t. However, DC parts can be swapped to DA, as they bolt right on. Both components are necessary to convert.
DC front shocks are slightly beefier, with a larger body. Maybe different damping to handle the extra weight?
Now, assuming all that is accurate, I have some questions.
Is it worth converting to DC shocks? Seems like parts for the DC are far more plentiful, and if I’m going to get a camber kit, might as well go with DC.
Are there any downsides to converting? And for those who have done it, would you do it again?
Since it might come up, my goal for the car is to have a streetable open-track / Time Trials car. Handling is the most important thing.
You can’t just bolt on a “conversion” to use all the front suspension from a DC on your DA. You could do it but it would require a lot of fab work and customization.
They are completely different designs, you can’t really think of it as the DC being the same as DA except missing the radius rods. You can’t just remove the radius rods from your DA and have your suspension work like a DC. If you remove your radius rods your suspension will be floppy as all hell and the wheel will move back and forth in the wheel well (caster) however it pleases based on the force applied.
If you look at the LCA you’ll see a large piece bolted to the side, this is the DC equivalent of a radius rod. It keeps the LCA in place so that it can only move up/down and not forward/backward. This is the same purpose that the radius rod serves on the DA.
[QUOTE=Dillon;2328215]
DC LCAs have no mounting points for DA factory radius rods. Thus DC LCAs can be mounted on DA, but you’d lose the factory radius rods.[/quote]
If you put DC LCA’s on a DA the car would be unsafe to drive for the reason I mentioned above. In order to make it work you’d need to fabricate a mount for the extra part mentioned above. Basically you’d need to mount parts #10 & #11 to your car so that the LCA would be held in place properly.
[QUOTE=Dillon;2328215]
DC has slightly different geometry than DA. DC upper arms, and the damper forks, are different. This is why front camber kits for the DC are plentiful, but camber kits for the DA aren’t. However, DC parts can be swapped to DA, as they bolt right on. Both components are necessary to convert.[/quote]
The fork and UCA should not be considered an upgrade. They are the same basic design, only slightly different sizes/specs based on the suspension geometry and chassis itself.
[QUOTE=Dillon;2328215]
DC front shocks are slightly beefier, with a larger body. Maybe different damping to handle the extra weight?[/quote]
It’s not that the whole shock body is beefier, just the lower portion that goes into the fork. Again, there’s no inherent benefit to the DC shocks from a design standpoint. The benefit to DC shocks is that the bodies are slightly shorter, so if installed on a DA you gain a little extra suspension travel if your car is lowered. I can’t speak for all shock brands/models, but in terms of valving on Koni yellow shocks the DA shocks are actually the most aggressively valved out of all the EF/DA/EG/DC shocks. So (assuming you have Koni Yellows) if you run a DC shock you gain suspension travel but lose valving. This is minimal though and I would assume that the extra shock travel has more benefit than the minor difference in valving would have an effect on handling.
[QUOTE=Dillon;2328215]
Is it worth converting to DC shocks? Seems like parts for the DC are far more plentiful, and if I’m going to get a camber kit, might as well go with DC. [/quote]
The shocks have zero to do with the camber kit. You’ll want a DA camber kit regardless of what shock you use. And using a DC shock does not mean you need or can use a DC camber kit. As I mentioned above, the benefit to using DC shocks is purely suspension travel. Or, in many instances, there may be a shock you want which is not offered for the DA but is offered for the DC, in which case you can just change to the DC forks and install the DC shocks.
[QUOTE=Dillon;2328215]
Are there any downsides to converting? And for those who have done it, would you do it again?[/quote]
It may have happened, but in my 15yrs of owning DA’s, being a regular on this site, researching suspension…etc I’ve never seen anyone put complete DC front suspension on a DA. I’ve seen the shocks, forks and UCA’s be swapped but never the LCA. I think there are differences in the knuckle as well, but I’m not 100% sure what they are.
[QUOTE=Dillon;2328215]
Since it might come up, my goal for the car is to have a streetable open-track / Time Trials car. Handling is the most important thing.[/QUOTE]
If handling is the most important thing then you’ll want to focus on suspension travel, proper shock valving, proper spring rates, and proper alignment settings. What route you want to go is 100% based on your budget. Let us know what you’re looking to spend on shocks/springs and we can point you in the right direction. And don’t forget the foundational stuff like making sure your ball joints, bearings, and bushings are all in good condition. Without those items attended to it really doesn’t matter what else you put on the car.
Awesome post, thanks! I suppose by “conversion” I meant only the fork and upper arm, to allow for use of DC shocks. Not the whole shebang. I didn’t know that the LCAs were so different, though. I did wonder what the DC has in place of the radius rods, and now I know. Although I do question why Honda changed over to that setup…especially considering the number of traction bar kits out there…
Anyway, based on your post I’ll just stick with DA shocks. I’m most likely going with Koni yellow and Ground Control, as that seems to be the best bang for the buck, and I’ve used them before on other cars. Urethane bushings (or maybe hardened rubber like Hard Race, I haven’t decided) are definitely in order. The RTABs are probably original and looking pitiful, 208K on them :shock:
There’s no reason to change the upper arm or the fork, there are no benefits here. The only reason to change the fork is if you want to use DC shocks, other than that there’s no benefit to the fork itself.
You won’t be disappointed if you replace all the bushings, install the Koni/GC setup and get a good alignment. Pair that with some good tires and an appropriate ride height and the car will handle very well.
What I’d like to do is post my understanding, and hopefully I’ll get some comments on how accurate (or inaccurate) it is. Note this is all about the FRONT suspension only. The rear, as I read it, is the same, except for the shocks / springs.