Suspension Questions (Not for FR-S)

[serialk11r]

Originally Posted by Dimman

It's an interesting challenge. Looking at how front biased the weight is, it will be tough to dial in nicely. It's going to want to overload the front tires in steady state turning and plow like a pig. But conversely being slightly imperfect on exit with limited weight on the back the rear will step out more easily. Add to it that it's a turbo motor with less throttle control/response it will probably be a handful. I don't know what the steering ratio is either, so corrections might be even harder.

Hence, active suspension? No more nosedive, no more roll, no rollbars, no stiff ass springs, no bouncing.

[Toyarzee]

Originally Posted by serialk11r

Hence, active suspension? No more nosedive, no more roll, no rollbars, no stiff ass springs, no bouncing.

?

[Dimman]

This is a shock dyno from a QA1 double adjustable shock.

What digressive means is that 'kink' in the curves. They go away from center quickly then taper more gradually.

The x of the graph is how fast the shock shaft is moving. So things like roll, squat, dive are 'slow' and hitting bumps are 'fast'. Strong damping at slow shock speeds makes a car feel responsive. But at high shock speed it feels harsh. Soft damping at slow shock speed feels sloppy, but high shock speeds are more comfortable.

What digressive does is ramps up the damping force quickly at slow shock speeds but then shims blow off some pressure at higher shock speeds so it doesn't ramp up as fast as the slow shock speeds. It's the best practical compromise of responsiveness to steering inputs and weight transfer movement, while reducing how hard bumps are felt.

The forces still have to be matched to the spring rates (and bump/rebound), but a digressive curve is generally a good thing.

[serialk11r]

Originally Posted by Toyarzee

?

Sorry, just thread hijacking. I'm saying, active suspension is awesome because you can do away with rollbars and stiff springs and dampers and stuff. You can even go over speed bumps without the car pitching, if you have enough suspension travel.

[Toyarzee]

oh, right. No i don't think that would be achievable here lol

[Toyarzee]

Ok, update time... Getting the truck back from my fab guy with new engine bay parts. I'm back to sourcing a better suspension and transmission setup.

I read the whole suspension tag thread from @CSG_Mike and there was indeed a goldmine of info.

I found I have a new alternative to keeping the solid rear axle. A new fab guy can help me swap in the IRS from a supra into the truck with minimal bed cutting. I assume this would be far superior to a typical 4-link setup and solid rear at the track. What would be the advantages of maintaining the solid rear axle?

[Toyarzee]

Problem solved, gonna rip it all out and swap in sub frame hub to hub from a donor mk3 supra. The canyon carving pickup truck is coming to a mountain road near you in 2016

[GSpeed]

Excellent, as I was reading this I was going to recommend you look into a donor rear end. There are lots of good ones out there that will get you 85% of the way there, and with some bump steer work you could have an awesome handling truck.

Glad you figured it out!

Jake

[Toyarzee]

My ideas embodied by a shop with more money lol: http://api.viglink.com/api/click?for...%2Fyeju3pbopMg

[GSpeed]

Yep! So many people like to nit-pick the fundamentals, but a lot of time the winning cars are good ideas executed to perfection, while the back of the field is full of great ideas that were never quite tested and developed fully. Just about any suspension can be made to handle with a little bit of thought.