Alfa Romeo Bulletin Board & Forums

Alfa Romeo Bulletin Board & Forums (https://www.alfabb.com/bb/forums/)
-   Spider - 105 & 115 Series (1966-1994) (https://www.alfabb.com/bb/forums/spider-105-115-series-1966-1994/)
-   -   Best Caster / Camber / Toe setup for Auto-X Alfa Spider S3? (https://www.alfabb.com/bb/forums/spider-105-115-series-1966-1994/683280-best-caster-camber-toe-setup-auto-x-alfa-spider-s3.html)

sporting 07-18-2019 02:27 PM

Best Caster / Camber / Toe setup for Auto-X Alfa Spider S3?
 
1 Attachment(s)
Hi Alfabb community,

I'm wondering what caster / camber and toe setup I should be running for Auto-X? I'm 'eating up' my tyres fairly quickly so any ideas would be much appreciated!

Best,

slowcreek 07-18-2019 09:20 PM

do you know your current alignment specs?

genericwood 07-19-2019 04:48 AM

It depends on a lot of things. But you might try this as a starting point. -2.5 degrees camber, as much caster as you can get. Tiny bit of tow in.

conedriver 07-19-2019 04:56 AM

It depends on what tires you are running. Tire Rack https://www.tirerack.com has manufacturer recommendations for some high performance tires (ex: Hoosier A7: 3 degrees negative camber). Caster can provide additional negative camber on the outside tire when cornering, but can be over done and result in the tire contact patch moving to the inside of the tire and the outside loosing grip. Especially for very wide tires, ask me how I know. For serious work, consider buying and using a tire pyrometer.

There are other suspension modifications available but this depends on what class & preparation rules you need to follow.

Quote:

Originally Posted by sporting (Post 8440562)
Hi Alfabb community,

I'm wondering what caster / camber and toe setup I should be running for Auto-X? I'm 'eating up' my tyres fairly quickly so any ideas would be much appreciated!

Best,


sporting 07-19-2019 11:35 AM

Quote:

Originally Posted by slowcreek (Post 8440708)
do you know your current alignment specs?

Slowcreek, I think I'm running -0.9 camber right now, and unsure of what caster and toe (probably standard)

sporting 07-19-2019 11:40 AM

Quote:

Originally Posted by genericwood (Post 8440774)
It depends on a lot of things. But you might try this as a starting point. -2.5 degrees camber, as much caster as you can get. Tiny bit of tow in.

Thanks genericwood - would too much caster hurt regular drive-ability tho? :smile2:

sporting 07-19-2019 12:26 PM

Quote:

Originally Posted by conedriver (Post 8440780)
It depends on what tires you are running. Tire Rack https://www.tirerack.com has manufacturer recommendations for some high performance tires (ex: Hoosier A7: 3 degrees negative camber). Caster can provide additional negative camber on the outside tire when cornering, but can be over done and result in the tire contact patch moving to the inside of the tire and the outside loosing grip. Especially for very wide tires, ask me how I know. For serious work, consider buying and using a tire pyrometer.

There are other suspension modifications available but this depends on what class & preparation rules you need to follow.

Currently on BFGoodrich G-force comp 2 - I've considered getting some really sticky Hoosier's too just haven't pulled the trigger yet. I've also thought of getting some wheel spacers for the back wheels yet unsure how large the spacers should be (5mm, 10mm?). I have approx 19mm of gap from the top of my tire to the inside ledge of the fender. Would playing with camber/caster/and toe affect this? It seems that I should be definitely be having more than -2.0 camber and a large amount of caster (any ballpark ideas to start with?) in complements to a slight bit of tow-in.

Haha, sounds like you have had a couple 'exciting' turn-ins with too much caster... :laugh2:

The car has a few modifications (I won't list them all here) but for suspension mod wise it is sitting on Koni Yellow springs and shocks, sway bars, and a chassis stiffener all from Centerline.

conedriver 07-19-2019 01:45 PM

Back when I ran a mostly stock '71 Spider, a friend suggested adding as much caster as possible, as also suggested by Eric Wood. This can be done by lengthening the upper front locating arm until it's inner end just touches the outer edge of the recessed mounting "box". When I did this, it increased the front grip sufficiently that I disconnected the rear sway bar to reduce the resulting oversteer. Such a change really helps but, as I said earlier, can be too much with really wide tires like my current 275/35x15 Hoosiers. Another side effect of lots of caster is really strong centering steering. On my car I can let loose of the wheel and the wheels will point straight ahead faster than I can move my hands. Of course, it's also harder to turn; turning the wheel raises the front while the weight wants to make the wheels point straight.

I occasionally use the steering wheel release to counter a little oversteer. And, some serous autocrossers run some toe out. Good for turn in, but darty on the street.

Quote:

Originally Posted by sporting (Post 8441024)
... It seems that I should be definitely be having more than -2.0 camber and a large amount of caster (any ballpark ideas to start with?) in complements to a slight bit of tow-in......


Vivace 07-19-2019 01:58 PM

Quote:

Originally Posted by conedriver (Post 8441084)
Another side effect of lots of caster is really strong centering steering. On my car I can let loose of the wheel and the wheels will point straight ahead faster than I can move my hands. Of course, it's also harder to turn; turning the wheel raises the front while the weight wants to make the wheels point straight.

I occasionally use the steering wheel release to counter a little oversteer. And, some serous autocrossers run some toe out. Good for turn in, but darty on the street.

I was about to ask this - I thought I read that some use neutral or a hair of toe-OUT. Makes it twitchier and faster reaction to steering input. Then when I read toe-in above I wondered if that was wives tale. The self-centering is interesting to hear.

Agreed - I would never run toe out on the street.

sporting 07-25-2019 10:05 AM

Quote:

Originally Posted by conedriver (Post 8441084)
Back when I ran a mostly stock '71 Spider, a friend suggested adding as much caster as possible, as also suggested by Eric Wood. This can be done by lengthening the upper front locating arm until it's inner end just touches the outer edge of the recessed mounting "box". When I did this, it increased the...

If I add as much caster as possible will this ruin and have some wear and tear my front bushings? I've had to replace 2 sets of bushings from Centerline now in under a year and a half and I'm curious if the caster/camber layout has any effect on this?

What measurement is 'as much caster as possible' in rough terms - approximately?

horsewidower 07-25-2019 10:10 AM

If you don't want to change for race weekends, you need to decide which is more important to you, street or Auto-x spec. Either will compromise the other.

nealric 07-25-2019 10:25 AM

I run 2.5* negative camber, zero toe, and max caster on my Spider (fast road type suspension setup currently). However, ideal alignment is going to be greatly dependent on your modifications. You may need to play with a few different settings before it handles like you want.


All times are GMT -7. The time now is 07:52 AM.

Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright 2002-2011 AlfaBB.com All Rights Reserved.

 
For the best viewing experience please update your browser to Google Chrome