I have red Koni EXTERNALLY adjustables both front and rear.
Just priced the Fox pieces. ouch...

Where do I send off the shocks to be rebuilt and also add more rebound?
What info should I supply the rebuilder? 1800 pound car 21mm torsion and 200 spring 22mm front sway
for autocross only. running R25A slicks. 30 pound wheel and tire each corner.

You can send them to Pro Parts or Koni-NA. You will need to tell them what you just wrote. At Koni-NA ask for Lee Grimes. He can point you in the right direction.

check www.koniracing.com

Hey, Joe... why Fox? What can they give you that Konis can't? I'm just curious.

More rebound is not always better.....

I'll second the suggestion: Send 'em to Koni NA.

You have Koni reds? Not yellows?

And Kevin asked the right thing... why more rebound? Too much rebound, and you can find the car jacking itself down at an autox. Some people have used this phenomenon to their advantage in Stock class autoxing... But I don't think you want to do that.

-Josh2

Koni NA in KY fairly close via UPS
Truechoice Koni Racing Service Page Good group of guys, hour away from home, gotten me out of a lot of binds. They used to beable to convert to double adjustables, so you can set it for what you need

They still can convert to doubles, but it's not terribly cheap. And the compression adjuster is located at the bottom. So, it's all well and good for the rears, but the fronts are another matter...

-Josh2

Because Fox looked pretty sexy. Then I saw how much it costs and I started to think not worth it for my boy racer wannabe asperations.

Well car it lighter with double the spring rate of stock. lighter wheels and tons more grip than I should have. The shocks got lots of miles on them and the rebound is not enough specially in the rear.

We video the runs both inside car and from the sidelines while the car is on course. it appears to us more rebound is required.

Josh the shocks may be red but the construction is the same as sports. Maybe an earlier model.

The sprung weight is greater than the unsprung weight. Seems to me if you could crank in enough rebound to overcome your spring presure, when the suspension uloads you could cause the inside tire to start spinning, or even come right off the ground in a hard corner.

Mike T

I was going to send mine to Truesports. There is a thread here somewhere about them.

I've heard some luke warm reviews of truechoice. No personal experience though. Folks I trust have recommended Koni NA for the work though.

-Josh2

Mike it SOOOOO doesn't work that way. or at least the idea of specifically valved shocks to match the parameters of the car this would not happen.

The idea of rebound it to prevent or slow the suspension from unloading.

when braking the weight shifts forward and unloads the rear tires. Rebound prevents this from happening. also slows the weight tranfer side to side when say negotiating a fast slalom. or those freaking chicago boxes.

How does additional rebound slow weight transition? And why would you want to slow it?

Too much rebound in transition and you unweight the inboard wheel.
Too much rebound under braking and you unweight the rear wheels.

Am I missreading what you're looking for? Are you lokoing for more damping during extension or compression of the shock piston?

Maybe I'm reading too much into it, but it sounds like you may want more spring...

-Josh2

looking for more damping during extension
The reason I need more rebound dampening is because I upped the spring rate by double. and reduced wheel weight by 10 pounds each and cut 200 pounds off the car.

And your Konis as-is don't have enough rebound damping when cranked up full??

While I may not have quite as light a car as yours, or running weigh-nothing slicks, the rest of my suspension setup is quite similar to yours (21 mm torsion bars, 200 # coils, 22 mm sway bar), and had yet to find a need for maximum rebound damping from the Konis. I tended to run at around 3/4 of a turn (1/2 range) plus or minus a 1/4 turn.

At full stiff, the rebound damping on the Konis is pretty firm, which is why I'm currious why you're looking for more.

-Josh2

Joe, it will be cheaper to buy new shocks. I also doubt Koni will even mess with rebuilding reds.

Just for some info...

Last year around this time I did some research into having my Koni Yellows converted to double adjustables.

Pro Parts wanted something on th eorder of $5-600 each.

TrueChoice was wild and wanted something like $700 per front, and $600 per rear.

And Koni NA? Much better. They would convert the rears to dubles for less than $400 each, and sell NEW double fronts for $250 each. Only drawback was the compression adjuster was at the bottom of the insert.

Food for thought...

-Josh2

Agreed. You want enough control from your shock damping to keep the tire from rebounding and bouncing off the pavement but little enough to allow the wheel to follow the pavement contour. Yes? Have you calculated wheel rate, motion ratio etc? Of course as in your original post if you gave them that information plus corner weights and unsprung weights they could valve your shocks accordingly.

Rebound controls weight transfer only within the ability of the unsprung weight to control the upward movement of the sprung weight.

Mike T

Josh said it in post #13 better than I've been trying to say it. And also Joe, I'm not disagreeing with you that you may require more rebound. Just trying to get a clarification on something that you touched on that has been nagging at me about shocks etc. A minor hijack I guess. Sorry and thanks...


Mike T

Brett; I just had my Bils rebuilt for $186, with machine work, rebuild, custom valving. Much cheaper than replaceing them with new.

Truechoice:
I have not had a problem with them, but they are so close I can if I have to. YMMV

Stephen

just for the record, i felt that i could have occasionally used more rebound than i could adjust with my yellow konis. particularly in the hillclimb, when i was constantly cresting the crown on the road (the car would get sooooo light), it was the only way i felt i could stay in control.

this was with 22mm torsion bars, 225# rears, 1900 lbs.

But if you had that much rebound, would your car have handled any better on the rest of the course??

Sounds like it was a problem of not enough suspension travel. Hmmm... 914's have been the subject of some wild bastadizations... Anyone consider putting a trophy truck style suspension under one????

-Josh2

probably, but that sort of heavy-light-heavy-light action was, essentialy, the whole course. i like your idea for suspension travel! Rally the car!