Suspension Theory/Chat Thread

[Highrev1]

Are you trail braking?

[Sirbelch]

Originally Posted by aki

That's what I was getting the feeling of, that it seemed to prevent too much roll (hence my toying with the idea of the slightly softer Si Sedan FSB). It's at the point where I let off the brakes and turn into the apex, so it's before getting on the throttle. When applying the throttle through the apex it feels great.

I haven't pushed my car in awhile though, ironically because the limit is higher and because I'm able to go a lot faster, esp with the tire upgrade to RE070. On an open road (where I can crash and hit a tree) even without any other cars I'm getting hesitant to push it. And today I had to replace one of the tires since the tire bead was bad according to Wheel Works, so one of the tires is a RE960 pole position instead.

Boy do I have a good story about that.

[aki]

Originally Posted by Highrev1

Are you trail braking?

No, and I understand trail braking keeps the weight up more to the front and thus offsets understeer, but I'd want the car to be somewhat neutral when letting off the brakes and turning, rather than feeling like it's going to plow straight into a wall.

The principle of trail braking irks me, too: I think the braking should be done before entering the turn--since tires have limited friction, it's sacrificing the friction that can be used for lateral grip to brake.

[LucasBlack]

Originally Posted by aki

The principle of trail braking irks me, too: I think the braking should be done before entering the turn--since tires have limited friction, it's sacrificing the friction that can be used for lateral grip to brake.

i see trail braking as beneficial on a situational basis. for, if done correctly, the ability of trail braking to help with rotation while still slowing down the car (to a possibly lowered degree), can counteract the amount of deceleration necessary. for, we slow down to be able to make a turn at a certain arc, correct? well, if we are trail braking to help rotation while we are slowing down, then we can be entering into our turning arc without directly relying on the "natural" turning abilities of the car -- forcing the rear around, which is typically the issue in our cars....

[drfters13]

17X8 wheel
38, 42, 45 offset. which would be the better of the three
225/40, 225/45, 235/40. what would be the best tire size
and the suspension im not to sure yet so i'll just wait for so more options to come out.
would i rub at all with some coilover installed with any of the offset and tire sizes i just mentioned?

[Sirbelch]

The smaller the offset, the wider the track, the better the handling. The smaller the offset the more strain on wheel bearings. I say a 235/40. I have 17x8 +45 with 235/40.

As long as you don't drop it like its hot, you won't rub.

[OhondaU]

Ok, was wondering if the rear MR for the Si that was bantered about a while back (1.1) is accurate. Can anyone who has measured it confirm this?

Highrev, your wheelrate estimate for the rear would be a motion ratio of about 1.3, hence my confusion.

Also, for giggles, has anyone measured the motion ratio for the anti-roll bars?

[Sirbelch]

Chris said that 97% of the spring rate reaches the ground in the front and 33% of the rear spring reaches the ground. However, the rear MR for the damper is 52%. % makes for much easier math of all because you don't have to square the ratio.

[OhondaU]

Ok, I must have missed that somewhere. Just wanted to confirm my measurement with someone. I measured 35% in the rear for the spring. Close enough in my book.

[Sirbelch]

I don't know that itnwas said in this thread.

[4play4dr]

ANYONE HAVE KSPORTS? i have a question for you..

[Sirbelch]

Non ofnthe regulars in this thread would ever own ksports. Try searching. There are threads on ksports out there.

[drfters13]

so i was thinking, if people just buy springs and install them. is the car going to handle better? for example- stock si and they just bought a pro-kit. is it going to handle better then stock? will it be worse?

also since there is so many springs out there, are some better then others? besides the the drop they give you?(tein,eibach,etc) will the pro kit and sportlines ride and handle the same? just a different drop? will pro kits handle better then skunk2 springs?

its because i read about people saying the car will handle better with just getting springs. and i just want to know if its just all in their head because they bought tein springs with nothing else and they think their car handles better

[Sirbelch]

The Pro-kit (and the rest of them) will all handle better initially due to a lower center of gravity (cg). However, your stock dampers (shocks) a going to have accelerated wear due to the lower ride height. This will cause the performance of the damper to decrease which in turn, decreases handling. So, you are going to need dampers with a shortend body that are designed to work with shorter springs, like Redshift's stuff.

[drfters13]

any one read sport compacts thing about suspensions? i read through it but didn't understand the shock dynos. so i'm checking out the shock dyno sticky. any thoughts about the test they did?

[Sirbelch]

I thought it was great. To bad those dynos don't have a scale on each axis, although, they did say that all the dynos were plotted on the same scale so you can get an idea of who is stiffer or has more damping here, less damping there. Too bad about the Moton car being a wreck. It was just as fast as the KW in rights (or lefts can't remember) and it was over lowered. The Motons should have spanked all. I also wish Koni had something too.

[chunky]

Has anyone else notice the differences in spring rates for various lowering springs and coilover setups?

Some companies are going with a higher spring rate up front and a lower spring rate in the back while others are doing the opposite with a lower spring rate up front and a higher spring rate in the back.

If my understanding of our cars is correct, would the latter not be the better setup? Yet it seems that the higher priced setups seem to be using the lower spring rate in the back?

[Sirbelch]

They use the lowered spring rate in the back for safety reasons. Companies don't need a reputation for building suspensions that will put a driver that doesn't know what he is doing into a tree.