Protech damper setup

[Jesspo]

Hello

I installed a set of protech (sjsportscars) dampers and springs today on my TC special. I do not found anything on which level the dampers must be adjust. The german instruction say 6clicks clockwise is the standard setup.

If you use the protech dampers Please tell me on which step you have adjust them.

Also interested is the ride high. In the moment i have near the lowest level and it looks higher thek the old spax dampers and springs. Maybe it is coming lower after the first driving but maybe i need shorter springs.

Any comment is helpful

Regatds Frank

[EuropaTC]

Hi Frank,

I have the SJS/Protech dampers on my car with higher rated springs.  I initially left them at zero for the first drive and then afterwards set them at mid-way, which on mine is 6 clicks.  There was no great thinking behind that, I just thought "13 clicks from one end to the other, set them mid way and see what it's like".  They're still there, the ride is much firmer than standard but I would expect that's due to the springs themselves more than the damper.

I'd just set at mid way and then increase or decrease depending on your driving style and local roads.

I started a thread about it at the time but called it "Spring rates" so it might have escaped your notice if you've done a search. There's photos of the car before & after, the part about the dampers comes towards the end of the thread.  I can take more photos of the suspension close up if it will be of any use, but it's not changed much from the ones in that thread.

 http://www.lotuseuropa.org/LotusForum/index.php?topic=538.0

Brian

[Jesspo]

Hi Brian,

thanks i made the middle setup but i have still a very spongy car. It is very loose on the tail with not much straight line stability. I have hoped to improve this with the new tires and new dampers but it is still very nervous to drive.

I think i will Change a bit the ride hight because it is very low on the front now. I like the look but i have Problems to see anything in the inner rear mirror.

greetings Frank

 
 

[EuropaTC]

Hi Frank,

The stance of your car doesn't look much different from mine, maybe a touch higher at the rear but the front wheelarch clearance looks very similar.  Because my springs are different from standard (250F/140R) I can't be 100% certain it's not all down to the springs, but I can say that my car certainly isn't "spongy" and the damping feels quite firm. In fact even with the OEM springs and dampers I couldn't have called it a soft ride and it was always stable on motorways, which makes me start to look at other potential causes for the "loose tail/straight line stability" comment.

Assuming when you replaced the rear dampers all the bushes and links were in good order, then my first guess is rear tracking and/or rear wheel camber. From what I've read, having toe-out on these cars is a very bad idea and does give stability problems, so that would be my first port of call.

Also a slightly embarrassing admission - when I first put my car together and did the "round the block" run,  due to my supreme confidence in my mechanical ability ( ) I decided to extend the test run and speed. At 50-60mph on a straight section the car was bouncing all over....   not caused by the soft damper settings but the simple fact I hadn't tightened up the lower link properly.   It emphasises the point about needing the rear end components in good order I suppose.      

I will take some measurements from my car later today which might help to compare your car setup with others.

Brian

[Jesspo]

Hi Brian

I made a second test drive today. I only changed the the hardnest of damping to front 8clicks and rear 4 clicks and the car was much better to drive. My tires are new rear has only 50km, so i will drive it now in this configuration and will see how it handle.

Thanks again for your help

Greetings Frank

[EuropaTC]

Hi again, and I'm glad to hear things are improving. I'm sure once everything is settled in you'll be pleased with the performance.

As promised I took some measurements from my car and have included 3 photos showing the easily accessible points.  I tend to make measurements from chassis points rather than bodywork, and use bolt centres where possible. The first is the front wishbone mount, which is approx 16.5cm from ground level. (that's the floor, not the cardboard sheets in the picture ! )

The second is the rear link, approx 18cm from ground level. The sump is 15.5cm at it's lowest point from the ground. All measurements to be taken with some leeway as I was only using a ruler so it's probably within 0.5cm but it gives an idea of how the car sits.

Brian

[Jesspo]

Hi Brian,

today i found time for the measurment.

mine is front 15,5cm, rear 18,5cm.

i think i will lower the rear a bit an give the front a bit more, that i came to front 16cm, rear 18cm.

greetings Frank

[EuropaTC]

Ok, this is a bit of a thread resurrection but I think it's better to keep the topic together rather than set another one running.   Since the last post in July I've been experimenting a bit more with my set-up and thought I'd add the latest findings in case anyone else gets the same spring/damper combination.

The front ride height was set to it's lowest setting on the dampers but now I've raised the front slightly although it's still lower than standard.  I've also lowered the rear of the car by degrees and moved from 140lb 14" springs to 160lb 12" springs as I couldn't get any lower rear height with a 14" spring.  I also wanted a bit more variance between Fr & Rear wheel frequencies hence the 160lb.

After much searching on the knowledgebase I found a comment (forget the poster, sorry) who mentioned that he'd measured clearances under the floorpan behind front & rear arches and had 5" Fr, 6" rear and apparently this advice originated with Richard from Banks Engineering.   So I measured mine there and...  yes, you've guessed it, 5" Fr, 6" rear.   I could really have saved a summer's worth of driving around the lanes       

Brian

......  but hey, it was fun finding out 

[Pfreen]

Hopefully you guys are still involved with thiscommunity.  Anyway, I bought the protech / spring setup from SJS for my tc special.  i set the ride heights to your numbers, no problem.  However, I checked the front camber and it is now -1-3/4 deg.  There is no clearance to modify my standard top a arms to get the standard 0 degree front camber by moving the top ball joint.  Did you all have this problem? 

[jbcollier]

Front camber off?  Something is bent or bushings shot.  It doesn't take much of a hit to bend an upright.

[Pfreen]

What is your front camber?

[EuropaTC]

Hi there,

With just a quick scan through my notes I seem to have -0.8deg on one side, -0.9 on the other, measured on a bar set against the rim edges.  I think the difference is down to operator error, the Chinese made gauge or maybe the steering wasn't dead ahead, I honestly don't know for sure.   If I'm honest I'm not too bothered about it, the car has been like that for a while and I can't say I've noticed anything odd about handling or tyre wear.   

If you want to get back to zero then I've heard of modifying the top ball joints (hard work) or elongating the holes in the wishbones. From the knowledgebase I picked up that 3/16" elongation should give -1.5deg of camber, so you'd be looking at 1/8" of filing for -1deg. If you look in there for posts by Jay Mitchell, he's written a lot about the suspension mods he did on his car for auto-X.

Once you're happy with the alignment the usual trick is to weld washers in place both to strengthen the area and make sure you always set both sides to the same camber next time it's apart. In fact welding washers in place used to be the go-to bodge on old wishbones anyway 

Brian

[BDA]

I can't see it in Brian's pictures, bur I'm willing to bet that his camber is adjustable. I have seen where people have slotted the lower A-arms and made different "washers" that fit in the A-arm that provide different camber settings. Beyond that, adjustable upper A-arms is probably you're best option if you want to run lower ride heights. You could, of course, fit adjustable lower or both adjustable upper and lower arms, but I think the added complexity is unwarranted (you'd need to concern yourself with caster).

What might be a secondary consideration is that the A-arms are purposefully designed to bend in an accident in order to try to save the frame. To that end, I changed only my top A-arms to adjustable units figuring that if I hit something, it would be more likely to impact the lower A-arms. I believe I have heard of the stock A-arms bending slightly such that it isn't apparent. This discussion will likely become moot in the not too distant future since the original A-arms are becoming more and more scarce.


My camber is -45'. Even that's in spec, I'll probably give my upper ball joint another turn the next time do an alignment which should get me to about -1° 8' because that's closer to the middle of the range (-30' to -1° 30').

[Pfreen]

I see in the workshop manual that the spec for front camber is 0 deg +_30'.  My camber is -1.5 deg both sides.  I cannot adjust to less, only more negative camber.  What do you all  think?  I have not seen the spec that BDA states.  What issue should I expect if I leave it as is?

[BDA]

I stand corrected. The front is 0° to +30'. The rear is -1° +/- 30'. Sorry for the confusion.