Coilover project update

[JMatt]

Here's the latest on my attempts to get race quality coilovers for the Hemi based cars:

I've now been driving on the rear shocks in coilover formation for about a week. Originally, there were some extra clearance issues that had to be addressed. We had some new pieces custom fabricated, and I installed them last Tuesday.

Here's the functionality so far:

Ride height:

It looks like I can drop the rear about 1 1/2 inches from stock without the springs ever unloading. If we add a take-up spring, or are just willing to live with the suspension completely unloading if you go airborne (not likely) then there's enough adjustment to lower the car about 3 1/2". I don't think that's even physically possible without the wheels hitting the wheel wells, so basically, I could lower the car as much as would ever be possible under any setup. I've adjusted ride height about 10 times by now. Because I don't have new suspension on the front yet, I settled with lowering the back about one inch, just to level the car out. I had it too low at first, and it looked like the rear was sagging. Popped it back up 1/2" to get a nice level stance.

Adjusting ride height took about 3 minutes per side.

Springs:

I have 550, 450, and 350 pound springs. I tested 550's first, and I should have been on a road course. The car was on rails, but ride quality on country roads was bone-jarring to say the least. Then I tried the 450 pound springs. Bingo! This is the spring for me for street use. Incidentally, I was able to completely change springs in 30 minutes, while talking on the phone. If focused, I think spring change-outs can be done in 20 minutes a side.

Rebound and compression damping:

Once I settled on the 450 pound springs for the street, I started playing with the damping. Setting both rebound and compression to almost full stiff was enough to make every little crack in the road transmit to the car. But I was still able to turn corners with a lot less lean than stock, and handling was much improved. The car would probably still understeer, but it was much closer to a balanced set-up. I'd need to be on a road course to actually flog my car to set it up best.

I then set the damping to full soft. The result was soft enough that the springs got a little bouncy, so I started dialing in some damping. I ultimately got a ride that was much smoother than stock, yet handled better than stock as well.

Adjusting damping from full firm to full soft took about 20 seconds per side.

Weight savings:

The suspension drops 5.4 pounds per side, but because the shocks are mounted body up, you drop even more unsprung weight, which is great for racing/handling. I dropped almost 9 pounds of unsprung weight per side.

Here's a couple of pictures to try to show what they look like.
http://i91.photobucket.com/albums/k290/jmattharnish/RearCoilover003a.jpg
http://i91.photobucket.com/albums/k290/jmattharnish/RearCoilover001a.jpg

These are still not a marketable coilover. There's too much custom work to make them fit. I think they may get down to about $900-$950 per rear pair including one set of springs. Currently, to replicate my coilovers is probably closer to $1200 per rear pair due to the needed custom pieces.

We'll see what happens.

Thanks for watching.

[36 chambers]

f ....ing awesome!!!!!!!!!!

[Cam]

Nice write up. It's damn cool seeing this starting to come together. J and I talked at SEMA about maybe setting mine up as well, but alas the first track day is only 2 weeks away. Looks like I'm gonna have to go a different direction.

So when do you expect to see a set of fronts??.

[JMatt]

Nice write up. It's damn cool seeing this starting to come together. J and I talked at SEMA about maybe setting mine up as well, but alas the first track day is only 2 weeks away. Looks like I'm gonna have to go a different direction.

So when do you expect to see a set of fronts??.
That's the million dollar question. It's going to be tough to do the fronts. I'm still holding out hope - but probably January.

[Samoan Tsunami]

are you planning to do any corner weighing and balancing?

you stated you were shooting to getting "race quality coilovers", and level stances are more an apperance thing than anything else. most cars serious on racing will run a front positive rake (rear higher than front) and not all times, especially when the driver isnt in the car will the car be level.

race coilovers usually are adjusted (fine tuning and such) when on corner scales to actually balance the handling of the car.

just askin' brah to see if these were gonna just be another coilover option like the Teins and KW, or actual race setups for autoX and stuff.

g'luck with it either way:)

[JMatt]

are you planning to do any corner weighing and balancing?

you stated you were shooting to getting "race quality coilovers", and level stances are more an apperance thing than anything else. most cars serious on racing will run a front positive rake (rear higher than front) and not all times, especially when the driver isnt in the car will the car be level.

race coilovers usually are adjusted (fine tuning and such) when on corner scales to actually balance the handling of the car.

just askin' brah to see if these were gonna just be another coilover option like the Teins and KW, or actual race setups for autoX and stuff.

g'luck with it either way:)
You're exactly right. I levelled the car for appearances - not for performance. Personally, I actually am doing this for drag racing purposes. Drag racers need higher compression damping, and looser rebound damping. I also will use lighter springs than what people would use for handling.

The whole point is - if you want to put them on scales, sit in the car, and set up the car for the road course - you can do that. If you want a comfortable ride on the street - you can do that. If you want to put 750 ft lbs of torque to the track (my power level) - you can do that.

One limitation - for people who really are hard core road racers, they'd start with a different shock valving than people who are hard core drag racers. Both sets would work great on the street too, but the setups are too far at extremes to have one shock be good for drag racing and road racing (in my opinion). Truth is though - the drag shock would still be better on a road course than our stock Nivomats, and the road course shock would be better at drag racing than our stock Nivomats.

Bottom line: Tunability. What do you want your suspension to do? Now I can make mine do what I want it to do.

[jg]

Very nice!!!

What custom pieces are necessary to bolt the new coilover in? It looks like a straightforward shock replacement- no?

[JMatt]

Very nice!!!

What custom pieces are necessary to bolt the new coilover in? It looks like a straightforward shock replacement- no?
The top mount is custom fabbed. I expect a different top mount for the final version. The lower spring perch also requires custom work, as our halfshafts are in the way of any typically coilover setup. Also, custom bushings need to be made for the lower mount. Finally, the shocks are American. The Nivomats are foreign. That means new bolt mounting hardware because the stock bolts are metric, but the shock bushings are standard.

You'd think this would be simple - and if it were being made for 10,000 cars it would be. Small batch custom fabbing is expensive though. Especially for a batch of two! (my left shock and my right shock) :)