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5-lug Swap with Suspension Tuned for RallyX?

5-lug rallyx racing

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4 replies to this topic

#1 subynut

subynut

    EJ Powa!

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Posted 21 September 2017 - 02:53 PM

Hello, Fellow Subie Owners! Long time no post!

 

I have a question:

 

PandaWagon, my 87 GL Wagon with an EJ25D and 5-lug swap is my RallyX/backup daily car. I am at a quandry with the suspension setup on her.

 

Currently:

IMG_5067
by subynut, on Flickr

 

Front

KYB AGX with 200lbs/in Ground Control coil overs with no preload

RX Sway Bar

Whiteline Strut Top Mount with extra Negative Camber and Positive Caster

Alignment set to about -2* of Negitive Camber and 0 Toe.

Legacy Bump Stops with 2/3 of it cut off for extra compression.

 

Rear:

Koni Yellow with 250lbs/in Ground Control coil overs with no preload

XT6 Sway Bar

 

RallyX Tires are 195/60R15 Cooper Weather Master Snow tires.

Street Tires are 205/60R14 All Seasons.

 

Her front is sitting pretty close to 2WD height with the street tires, which I like how she sits and she handles amazing on the street! 

The rear could come down some, but I haven't been able to do that without basically sitting on the bump stops in the rear. Which makes the rear unpredictable while on the race course. :/

 

She handles pretty decent on the RallyX.

Untitled by subynut, on Flickr

 

But! She's bottoming out the front suspension on decent bumps at the RallyX.

 

Closer wheel arch spaces:

Front:

Untitled
by subynut, on Flickr

 

Rear:

Untitled
by subynut, on Flickr

 

 

I have about two inches before the bump stop on the front. I've tried 250lbs/in springs, but at those rates, she's too bouncy and her nose is going airborne. I've played with the shock setting, but all I seem to do is make the bouncing worse. The 250s work great at high speeds, but that's way too fast for RallyX.

 

Rear is ok as far as the springs, but I'm having a challenge with shocks. The Koni's appear to be wearing out. They're not dampening like they used to. (Abount 2.5 seasons of RallyX and some AutoX on those.

 

I understand that travel is a biggie for RallyX, but I don't want to
lift the suspension anymore than 4WD height to keep body roll under
control. (Preferably, I'd like to keep the suspension at 2WD height. But
I don't know if that's possible for RallyX)

 

 

So, this is my ideas:

Add preload to the front coil springs to lift the nose some

Concerns:   Will I bind the coil spring before hitting the bumpstop?   (I'll get a picture of the coil over in it's current state later)

 

225lb/in springs

Concerns:   Will that still be too much spring?

 

STi front springs

Concerns:   Will that lift the nose too much?

 

I don't have STi springs or the 225lb/in coilover springs, so, I'm thinking I'll try adding preload and see if I can mimick the RallyX on the street.

 

 

Am I on the right track with just adding preload to the front coil overs to lift it a little?



#2 Numbchux

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Posted 22 September 2017 - 04:13 PM

Obviously RallyX course conditions can vary a lot from location to location, but that looks way too low for the events out here. I would definitely go up in the front.

 

I've done several rallyXs in other cars, and once life frees up enough that I can have a truck and trailer, I'll be doing it in my XT6 (closest events are 2 hours one way, most are about 4 hours).

 

I currently have GD WRX front springs on '94 T-leg GR2s on the front with 250 lb/in 12" long ground control coils on EA82 wagon GR2s in the rear. I'm pretty happy with the way it handles (I'd like to lengthen the leading rods for more castor). And I've got a bunch of travel. Quick google search says that's a 163 lb/in spring, and they had a fair amount of preload.

 

Pictured on 205/50r16 Hakkas on 16x6.5+48 wheels

20170102_124246 by Numbchux, on Flickr

 

20160330_174136 by Numbchux, on Flickr

 

 

I would not go any stiffer than 200 lb/in in the front. the EJ25D is probably lighter than the ER27....the concern about coil bind will depend on the spring length, and therefore how high you have the adjusters. Post a picture of where your preload adjusters are, if they're above halfway or so, I'd grab a pair set of springs that are ~2" longer. I had ground-control sleeves on the front of my loyale, cranked as high as they would go (8" springs, IIRC), and never had them bind, but never saw RallyX use.



#3 carfreak85

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Posted 25 September 2017 - 09:31 AM

You're asking the impossible unfortunately.  You really want a tall, softly sprung suspension for any sort of rally activity, the dampening can still be relatively stiff, but the spring rates should be much softer, and body roll will just be a part of the game.

 

I would probably even drop the anti-roll bar sizes, maybe go RX in the rear (bigger than GL, to help with rotation) and GL in the front.  There are lots of one-wheel bumps in rally, and anti-roll bars can severely limit wheel travel in these situations.  If you can maximize individual wheel travel (i.e. smaller, or deleted anti-roll bars) you can run a stiffer spring and dampening, since a smaller/no bar effectively reduces the dynamic spring rate.)

 

 

My suggestion, since it seems you want street handling as well as rallyx ability, would be to find a nice set of rally-friendly coilovers (reasonable spring rates without a shortened shock body) and change the ride height based on that day's activities.



#4 subynut

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Posted 25 September 2017 - 09:37 AM

The front springs are 10" long and I have no preload set. The adjusters are all the way down. However, the springs are snug enough to not rattle around or pop out of the spring perch when the front is unloaded.  I'll have to get pictures of the struts later this evening.



#5 subynut

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Posted 25 September 2017 - 09:57 AM

carfreak85,

 

   How much stiffer of a spring would I have to go if I removed the anti-roll bars?  I tried 250s up front without the anti-roll bar, but the nose was nowhere near as planted on the RallyX as it is with the 200s and RX anti-roll bar.

 

   I have tried the RX rear anti-roll bar, but I just couldn't get enough rotation as I do with the XT6 anti-roll bar. Even with 320lb/in springs back there, it just would lean too much and the higher spring rates would just bounce the tail around. Very unpredictable. Hence why I dropped back down to the 250lb/in springs and the XT6 rear anti-roll bar.

 

   I realize the wagon doesn't weigh that much more than a sedan or the XT, but that weight is up higher back there.

  Perhaps I just haven't found the right spring rate/dampening ratio...







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