Project Car / Motorbike thread. Let's see 'em.
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Asininedrivel
caviar connoisseur
Henry Catchpole put up a comparison on Youtube between an Evora and a 992 recently. The Evora held its own despite its age, and Henry's visible enthusiasm driving it was pretty telling.
Also I don't think I like the new 911. This is weird as I love every 911 (even the 996) but the styling on the new one jars from some angles (particularly the front) and it's too heavy. That you seemingly must spec the sports exhaust unless you want a muted vacuum cleaner soundtrack is a dud move too.
The GT3 Touring / GT2 RS / 993 Turbo / Singer / Ruf (changes weekly) spot in my dream garage is safe.
link1896
Mr Greenfield
Will have the ZF transmission apart this weekend or next for its 100K service. fluid, filter, solenoid kit, filter and the stupid plastic bits between mechatronics body and housing.
if that doesn't fix its issues, clutch pack A's bushing is shagged and the local tranny dude can work his magic.
if that doesn't fix its issues, clutch pack A's bushing is shagged and the local tranny dude can work his magic.
I have an assortment of riches from which to make either adjustable strut tops or coilovers and adjustable strut tops for the XR4. I have next week to do it.
The two black struts are the XR4 units and the red springs are XR4 lowered springs. The Fortuner strut on the left is going to be sacrificed to make a jig so we can dyno the factory struts and these black Pedders ones. The potential coilover shocks (BMW 5 series rears) are fully rebuildable which means custom valving is an easy job, the red ones also have variable valving. These coilovers are threaded to allow different lengths and bases to be fitted. I can also turn a new base for these that will allow the struts to clamp into the XR4 knuckle so I am thinking of just going straight there and forgetting about the XR4 units. I can adapt the red camber plates (Commode) to suit. All we need are new springs.
These will all get dynoed this week and we can see what needs to be done. If the Pedders struts are still ok I will give them a run at the next sprint.
Decisions...
Also tracked down an engine management issue that originally was diagnosed as an intermittent fault on the crank angle sensor but actually turned out to be a bad coil pack which would occasionally fail to fire. All good now.
The two black struts are the XR4 units and the red springs are XR4 lowered springs. The Fortuner strut on the left is going to be sacrificed to make a jig so we can dyno the factory struts and these black Pedders ones. The potential coilover shocks (BMW 5 series rears) are fully rebuildable which means custom valving is an easy job, the red ones also have variable valving. These coilovers are threaded to allow different lengths and bases to be fitted. I can also turn a new base for these that will allow the struts to clamp into the XR4 knuckle so I am thinking of just going straight there and forgetting about the XR4 units. I can adapt the red camber plates (Commode) to suit. All we need are new springs.
These will all get dynoed this week and we can see what needs to be done. If the Pedders struts are still ok I will give them a run at the next sprint.
Decisions...
Also tracked down an engine management issue that originally was diagnosed as an intermittent fault on the crank angle sensor but actually turned out to be a bad coil pack which would occasionally fail to fire. All good now.
hifiandmtb
Sphincter beanie
Is there nothing off the shelf for the XR4 to suit your needs???
No camber plates are sold here. I am going to have to perform fairly major surgery on the strut towers for these. Lots of stuff in the UK but it all adds up in $, making stuff is easy. Nothing commercial is compression biassed anyway which is what we need.
Cardy George
Piercing rural members since 1981
Could you rustle up some links on compression bias so a pleb like me can learn stuff?I have an assortment of riches from which to make either adjustable strut tops or coilovers and adjustable strut tops for the XR4. I have next week to do it.
The two black struts are the XR4 units and the red springs are XR4 lowered springs. The Fortuner strut on the left is going to be sacrificed to make a jig so we can dyno the factory struts and these black Pedders ones. The potential coilover shocks (BMW 5 series rears) are fully rebuildable which means custom valving is an easy job, the red ones also have variable valving. These coilovers are threaded to allow different lengths and bases to be fitted. I can also turn a new base for these that will allow the struts to clamp into the XR4 knuckle so I am thinking of just going straight there and forgetting about the XR4 units. I can adapt the red camber plates (Commode) to suit. All we need are new springs.
These will all get dynoed this week and we can see what needs to be done. If the Pedders struts are still ok I will give them a run at the next sprint.
Decisions...
Also tracked down an engine management issue that originally was diagnosed as an intermittent fault on the crank angle sensor but actually turned out to be a bad coil pack which would occasionally fail to fire. All good now.
Will do.
Here is some general discussion on damping with a bit about compression biasing damping. Mostly damping is a black art when it comes to racing. You need to calculate the motion ratio of the suspension in order to determine how stiff the system needs to be. Essentially there are three stages. Underdamped where the car will pogo with the bumps causing motion in the springs that the dampers cannot control. Overdamped, which is demonstrated by the yellow shocks below. In this case if the damping is too strong the springs can be rendered useless as continued bumps force the suspension to one or other sets of bumpstops because the suspension doesn't allow the springs to cycle. Finally critical or ideal damping. This is sort of possible but with so many variables such as tyre pressure, load, speed and bump sizes it is only ever critical over a narrow range and then becomes under or over damped elsewhere.
I have had the opportunity of driving my 4wd in all 3 states and in my view for the road it is better to be slightly underdamped at all points that ever be overdamped but or should I say BUT too underdamped and it is uncomfortable and dangerous. My wife best summed it up by saying the underdamped stuff meant that after driving over a speed bump the car kept bouncing and was more sensitive to undulations and wind. Overdamped and all your teeth would fall out and when it was critically damped driving over a speed bump was more heard as a noise than felt as a bump.
https://www.f1technical.net/forum/viewtopic.php?t=8937&start=45
I will admit to relying on my mate who is something of a guru having revalved trophy trucks and track cars as well as my 4wd shocks and many others. Essentially the concept is to reduce the impact bumps and undulations have on the ride height and control and limit the compression, rebound on the other hand is weaker and lets the shock reset. This is opposite the set up most road going vehicles have which is a compromise on ride quality as well as reflects the state of our roads.
The shocks in that pic were run on a dyno yesterday and these are the results. Pics edited to just the graphs.
This is typical of the aftermarket struts available for the XR4, hopefully I will be able to strip the stock struts out and look at them too. The stock XR4 setup is pretty damn good and I will be interested in how they look compared to these. The results are 980N rebound with 440N compression which is as I said pretty typical.
The yellow shock which incidentally was a BMW 5 series rear sports shock is as follows:
This is rubbish. The 5 series would need to weigh 5 tonnes to make sense of the numbers. 5kN rebound and 1.4kN compression. Crazy stiff and it would ride like the springs were welded up. Worse still on a track each time the springs compressed there would be a real risk that the spring wouldn't overcome the damping before the next bump was hit and so on until it was riding on the bump stops.
The red adjustable shock which is marketed for R32/33 Skylines is better and shows that the adjustment actually does something.
At the softest setting it is around 1.8kN for both compression and rebound.
The yellow and red shocks are generic things from two different 'specialist' aftermarket suppliers. Both shocks are gas pressurised. I will contract the supplier of the red one on the off chance he gets them things made up. If they cannot valve them to our specifications (1.5kN comp / 0.5kN rebound) I will try and get some that aren't pressurised so we can strip them safely. If not then I will have to see what happens...
In any case the red shock can be used and I will start machining bits to mount these as coilovers on the track XR4. Springs are easy to get and we have local sprints each month up to Christmas to see what is happening.
Does any of this help?
I have had the opportunity of driving my 4wd in all 3 states and in my view for the road it is better to be slightly underdamped at all points that ever be overdamped but or should I say BUT too underdamped and it is uncomfortable and dangerous. My wife best summed it up by saying the underdamped stuff meant that after driving over a speed bump the car kept bouncing and was more sensitive to undulations and wind. Overdamped and all your teeth would fall out and when it was critically damped driving over a speed bump was more heard as a noise than felt as a bump.
https://www.f1technical.net/forum/viewtopic.php?t=8937&start=45
I will admit to relying on my mate who is something of a guru having revalved trophy trucks and track cars as well as my 4wd shocks and many others. Essentially the concept is to reduce the impact bumps and undulations have on the ride height and control and limit the compression, rebound on the other hand is weaker and lets the shock reset. This is opposite the set up most road going vehicles have which is a compromise on ride quality as well as reflects the state of our roads.
The shocks in that pic were run on a dyno yesterday and these are the results. Pics edited to just the graphs.
This is typical of the aftermarket struts available for the XR4, hopefully I will be able to strip the stock struts out and look at them too. The stock XR4 setup is pretty damn good and I will be interested in how they look compared to these. The results are 980N rebound with 440N compression which is as I said pretty typical.
The yellow shock which incidentally was a BMW 5 series rear sports shock is as follows:
This is rubbish. The 5 series would need to weigh 5 tonnes to make sense of the numbers. 5kN rebound and 1.4kN compression. Crazy stiff and it would ride like the springs were welded up. Worse still on a track each time the springs compressed there would be a real risk that the spring wouldn't overcome the damping before the next bump was hit and so on until it was riding on the bump stops.
The red adjustable shock which is marketed for R32/33 Skylines is better and shows that the adjustment actually does something.
At the softest setting it is around 1.8kN for both compression and rebound.
The yellow and red shocks are generic things from two different 'specialist' aftermarket suppliers. Both shocks are gas pressurised. I will contract the supplier of the red one on the off chance he gets them things made up. If they cannot valve them to our specifications (1.5kN comp / 0.5kN rebound) I will try and get some that aren't pressurised so we can strip them safely. If not then I will have to see what happens...
In any case the red shock can be used and I will start machining bits to mount these as coilovers on the track XR4. Springs are easy to get and we have local sprints each month up to Christmas to see what is happening.
Does any of this help?
Cardy George
Piercing rural members since 1981
It does. But I'll have to read it a few times to get around all the points.
Am I right in assuming it's tuned for track first, everything else second?
Am I right in assuming it's tuned for track first, everything else second?
born-again-biker
Is looking for a 16" bar
Is the requirement for a compression biased tune because of your vehicles' particular motion ratios / characteristics?
... Or is it a method for any track car where the surface will generally be very smooth and the compression forces are only brake / accelerate / cornering induced g-force...?
Does the compression biased set-up remove a lot of the 'work' that the sway bars would be doing in a more balanced, or rebound-stiffer, design?
... Or are they still separate roles?
Are monotube dampers a given for this?
I'm assuming twin tube would be too soft or just not tuneable...?
Sent from my LG-H870DS using Tapatalk
... Or is it a method for any track car where the surface will generally be very smooth and the compression forces are only brake / accelerate / cornering induced g-force...?
Does the compression biased set-up remove a lot of the 'work' that the sway bars would be doing in a more balanced, or rebound-stiffer, design?
... Or are they still separate roles?
Are monotube dampers a given for this?
I'm assuming twin tube would be too soft or just not tuneable...?
Sent from my LG-H870DS using Tapatalk
Predominantly track oriented. Twin tubes are tunable too, just a matter of changing shims.
Sway bars have a different role tieing the two sides together. Most sway is sorted by shocks if they are done right.
Sway bars have a different role tieing the two sides together. Most sway is sorted by shocks if they are done right.
hifiandmtb
Sphincter beanie
Charts for the Billie coilovers I had rebuilt for the 111R but never fitted:
Whatcha think?
Whatcha think?
For a light car maybe too much rebound. I am not a guru, just a very naughty boy.
Steven knows his stuff though.
Steven knows his stuff though.
Flow-Rider
Burner
A bit of Lake side history with Norm Beechey for the win.
hifiandmtb
Sphincter beanie
Haakon
has an accommodating arse
Nope, all good! Glad the towbar was there as it was a pretty light tap really, would have been just annoying minor damage.
If you’re going to hit my car, try to do it properly and write it off!
fatboyonabike
Captain oblivious
is that a towbar or a rear mounted dildo?.....Im assuming the latter
one up front, one out back!
one up front, one out back!