Springs for track use

[Linus27]

I was always led to believe that Honda spent a lot of time and effort in getting the suspension right for the DC5. So much so that stock is pretty much perfect and that updating just the springs was a backward step. Unless you were going full race setup (Coilovers etc.), then it's better to stick with OEM springs. I'm sure I read this somewhere.

So, I'm now at the crossroads where I am going to do occasional track days (5 or 6 a year maybe) as well as using my car for daily use and I'm wondering if the above is correct. I was considering some Spoon springs but also wondering if sticking with OEM is the better option.

Anyone have any thought on the best option for our car is?

 

[James-T]

I did a trackday a month ago on the standard suspension setup and there was far too much body roll for my liking.

I didn't have many spring options (facelift), so spoke to Tom at TGM. Getting Bilstein B14 coilovers fitted next week.

 

[Linus27]

Found the link where this is discussed.

http://honda-tech.com/acura-rsx-dc5-honda-civic-ep3-32/wanna-rsx-ep3-suspension-tuners-good-video-2414044/

 

[James-T]

Ah yes, I brought that up a few weeks ago. The problem with lowering these cars is that the steering arms end up changing the toe of the wheels when going over bumps (bump steer).

This can now be rectified with the Tegiwa rack riser / Shorter steering arms with more thread for track end rods / inverted tie rod ends.

Lowering a little doesn't seem to be an issue, but lowering a lot does - so something which I mentioned above should be carried out.

 

[Linus27]

So, is Spoon/Eibach Springs considered lowering a little or still too much? The article even seems to indicate that Spoon themselves are not keen on using their own springs to lower the DC5. I can't find the video but it seems to point at either leave as OEM or go full race setup.

 

[James-T]

Many people lower on Spoon or Eibachs with no problem at all regarding geometry. Tom at TGM mentioned that if you're lowering 40mm+ then you will start to encounter the bumpsteer.

 

[Linus27]

Thanks James for your input. I have Bedford next Monday so I will see how the car goes. It's standard apart from Spoon 2-1 manifold, Spoon b-pipe, AEM V2 and remap. I also have the tower strut brace from Tom's race car fitted so it will be interesting to see how the balance is and how I find the body roll.

 

[Rom]

In a very basic nutshell, simply lowering a car usually worsens the handling.
It may feel like it rolls less, but the negative effects often mean you lose desirable features.

There is a point, when a low center of gravity is outweighed by the rest of the geometry angles being too far out to function correctly. The COG is very different to the roll center height, but they are related and act upon each other.

The most common thing is springs, on standard dampers. If you are lucky, you might actually invest in camber arms / bolts and a geo.
Springs with oem dampers and a full geo are ok. At least you are correcting the camber and toe changes you get when you lower the car.
If you dont get a geo (with arms and bolts or its almost pointless) you will be running the run settings for anything to really work remotely well. So you have a lower car, but worse handling. Fine for average road use, it looks lower.

Even with springs, arms and geo. You still suffer multiple side effects. The angle of the bottom arm changes. The angle of the steering arm changes. So the angles Honda spent £££ on, to achieve great handling, have just been ruined by some monkey who lowered his car.

In comes extended ball joints which aim to correct the lower arm angle. Rack risers, which aim to correct the steering arm angle.
A simple excercise...

Put your elbows out to your side, hands in front of your chest. Your hands are the inner pivots of the lower arms, mounted to the subframe. Your elbows are the hubs / wheels. Keep your hands still, as the subframe is an unsprung component, its fixed. Now raise your elbows. This is what you do when you lower the car.
Honda wanted those arms to be at a specific angle, or range of angles during use. The same principal applies to the steering arms, these also move in relation. Again, Honda have a desired range of operation.

So...
A car with just springs will be worse handling. Regardless of what its drivers butt dyno tells you.
A car with springs and a geo (bolts and arms), will fair better, but the angles will still be incorrect. If not too low, they may not be too bad.
A car with springs, extended ball joints, rack riser, geo should handle better than stock. As its actually making use of the lower COG, and has its angles corrected. Now this isnt to say its perfect, i doubt the angles will be exactly as stock. But its the best option you have.

Ideally, shorter dampers would be used. As the oem ones will now be running on a reduced compression stroke, due to a lower car limiting to travel. Again, if not too low, the effects arent so bad.

Suspension is a dark art. Most people have little to no understanding of it. Other than low looks good. Im far from expert, but I dabble

 

[Rom]

So, is Spoon/Eibach Springs considered lowering a little or still too much? The article even seems to indicate that Spoon themselves are not keen on using their own springs to lower the DC5. I can't find the video but it seems to point at either leave as OEM or go full race setup.

I would take that article as Spoon talking about just fitting springs to the car. In which case, I fully agree. Fine if all you want is that lowered look.

Eibachs have funky rake, reverse rake is not ideal. Especially on track. Most of the time you either accelerating or stopping, weight transfer is going on all the time. Which is compounded by the front of the car already being higher than the back.
Its something drift cars utilise. But front wheel drive, you want the weight over the front wheels for acceleration and braking.

 

[Linus27]

Thanks Rom, I tend to come from the same thinking as you. Honda spent millions on getting the suspension right and considering the car was designed for track use in mind, if the car would be handle better lower, then they would had made it lower.

As for the article, then yes, the Spoon guy was saying either full on race car set up or stock setup is best. Anything in between is poorer for the cars handling. So changing just the springs will undo all of Honda's good work.

 

[Dan34]

Rack raisers actually do more harm than good on track/racing. They increase toe in on bumps.

 

[James-T]

Rack raisers actually do more harm than good on track/racing. They increase toe in on bumps.

Please elaborate.

 

[El_Boomo]

Do Eibachs actually give reverse rake or is it just the way they look because of the higher front wheel arches?

 

[mike.williams]

Avoid the rack raiser bracket as it causes toe in under compression. It may feel like it reduces bumpsteer but under track driving conditions when the suspension is highly compressed toe in is the last thing you want up front.


Dan knows because i sent him the article


There is an engineering report in the first page of the track chat 2 thread on clubrsx if you want to read it.

Best mod is extended balljoints and caster increase at the top mount.

Aftermarket Spring rates should mimic the oem spring rate ratio which the rear is double the front

 

[James-T]

Just had a read of that on ClubRSX - pretty interesting!

 

[MeisterR]

Here is what I can tell you.
We look into this, and work out that rack raiser is not a good thing, as other pointed out it cause a lot of issue with toe.

We actually work out what it was and had it tested out on the track and on the road.
The main cause of the issue is actually "side load", and so we have engineered a secondary reinforcement in our MeisterR GT1 coilovers to increase the side load capacity.
The suspensions already been tested on a road DC5 and a race EP3, both do not exhibit the bump steer issue.

The best result was from the DC5 as it drove in with the bump steer, and drove out without after we added in our reinforcement.
So we know it work and it pin point the cause of the result.

Jerrick