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Are these alignment specs unstreatable?

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shootist View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote shootist Quote  Post ReplyReply Direct Link To This Post Posted: Jul/25/2017 at 9:07pm
Hey 304, I am running the CF IFS and 4-link rear. I pretty much run stock spec on the camber and the caster on mine is set to +4° I run the flaming river manual mustang 2 rack and it is a little tough turning at rest but not intolerable and easy turning at speed. I haven't gotten seat time on the auto-x yet but figured it would be a good starting point and we will go from there. Driving on the street there really is no bump steer issues and I have to say the geometry on the Control Freak IFS is done very well. I could run the caster up to around +6-7° but I highly doubt it would be necessary or beneficial to go with more caster than what I am running since as it currently sits you can release the wheel and the car goes perfectly straight at any speed (I have had it up to 110-120 mph and the same result). I would imagine the car would run well into the 150-160 range and still maintain stability rather easily but we will find that out soon enough as I am rapidly approach project completion and race time.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 343sharpstick Quote  Post ReplyReply Direct Link To This Post Posted: Jul/25/2017 at 10:12pm
Sounds like the rack and pinion behaves much differently to caster settings than the stock steering box. No surprises there. Even with 7 degrees caster, steering can be done with my finger tips, which I'm not a huge fan of. It does self-center way better however.

I have a new type 2 pump, and will be looking to do a faster ratio box, so perhaps that will give me more feel.
As a side note, with trunnions and only 2 degrees of caster the steering self center was pretty awful. Made AutoX very interesting, lots of elbows and hands flying around.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote shootist Quote  Post ReplyReply Direct Link To This Post Posted: Jul/25/2017 at 10:29pm
I haven't really had a chance to throw it into corners just yet but as you mentioned the self-centering on my setup at 4 degrees seems to be a good compromise between steering feel and self centering ability. I am pleased with the street manners but what makes for easy street manners is not always best for track days. That said, I am more trying for the happy middle ground between flat out track car and easy driving street car. I don't mind a little heavier effort since it is not a daily driver but I also will be adding an EPAS setup very soon and that will allow me to dial in heavy assist when parking and virtually remove assist at speed so I can get that valuable feedback from the manual rack.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Jul/26/2017 at 3:57am
Hey guys... Thanks for more input. And yes different rack setups, suspension limitations and what I see as for tire size seems to show various differences in how one feels the steering and how well it performs.

Shootenist, i think once you upgrade your wheels and tires, you may see added benefit with more caster. Though you have a different rack setup, and may find a wall for you around 6 degrees. Just by effort.

Sharpstick, your steering setup has its differences as well. So with all off ours in comparison it is like a mixed bag of fruit. So, I may be a wee more out of the box just by how different my setup is all around.

Maybe once we get input from Jersey Joe, on his build, we may see more caster. I think he may have a max setup like mine with wheels and tire fit, and race setup.

Since I am in the dark with trying to put my odd setup into a general mix, it is mostly a question of large wheel base with more modern performance setups. As the Mustang crowd does not fit exactly into what I am expecting, as of yet. Mostly because I am in uncharted waters. Just hoping because I kept as much as possible my Mustang equivalent, I can expect to keep up closer to what they run on the track and streets.

Though we all are mixed on how we all like our rides to feel, and function. Some like comforts more than man handling. So hearing how steering effects everyone's tastes, i am always listening, as to be more cautious to safety than trying to keep up with the other guy. Perhaps I will find 5 degrees my overall setting for street and may bump for track. Was thinking I could have one setting and be done with it.

At least with more replying, we all can see how so many factors effects how one in er acts with their steering.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote iapexl8r Quote  Post ReplyReply Direct Link To This Post Posted: Jul/26/2017 at 11:12am
It all depends on how agressive you plan on driving on the track. If you plan on pushing the car into the 80% and above range you will need at least 2 deg of neg camber the result of less camber than this is your tires will not live through one track day, the outside edge will get destroyed. To aleviate the wear from driving on the street with that camber you may want to tighten up your toe to a 32nd of an inch. I have been running 2 1/2" of camber on a dual pourpose street/track car for many years with no problems.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ghinmi Quote  Post ReplyReply Direct Link To This Post Posted: Jul/26/2017 at 11:17am
You may want to revisit your wheel/tire choice.  For autocross, the 9" wheel is waaay too narrow for a 295 or 315.  You would probably be better off with a 275 or even smaller on all 4 corners.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Jul/26/2017 at 12:40pm
Originally posted by ghinmi ghinmi wrote:


You may want to revisit your wheel/tire choice.  For autocross, the 9" wheel is waaay too narrow for a 295 or 315.  You would probably be better off with a 275 or even smaller on all 4 corners.



I figured the front was pushing it as it was. 275 was what I thought originally until the Cobra guys started on edging things up a bit.

There was one who did 285 for size, but that is the smallest up front I have seen.

As for rears... I should be able to fit even larger tread widths by my 65" wide axle. Though I think you may be on to tire side wall roll over. Don't have all that weight centered, as many do with their track car. I figured the lighter rear would allow for wider tires. I don't want to go any smaller than 305.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Jul/26/2017 at 12:46pm
Originally posted by iapexl8r iapexl8r wrote:

It all depends on how agressive you plan on driving on the track. If you plan on pushing the car into the 80% and above range you will need at least 2 deg of neg camber the result of less camber than this is your tires will not live through one track day, the outside edge will get destroyed. To aleviate the wear from driving on the street with that camber you may want to tighten up your toe to a 32nd of an inch. I have been running 2 1/2" of camber on a dual pourpose street/track car for many years with no problems.


Ah, there was info on 0 toe in and -2.5° Camber.

May try that, and work my way to 1/32" toe in increments.

I figured track would require no more than -5° camber, so I expect on one adjustment done in between.

My main reason I want very close to track settings, is so I can be use to one setup and not have to go between what I think was good but may not be once changed.
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
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79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 304-dude Quote  Post ReplyReply Direct Link To This Post Posted: Jul/26/2017 at 5:41pm
Ok guys... I got around to looking at tire options and realised that some of the track Cobras and GT500s are using wider rims or combination.

Also what helped confuse me is you can put the same tire that works on a 9 wide rim of the same size on 10 inch rim. So my mixed bag of comparisons threw me a curve.

So back to square one.

P275/45R17 all around.

Toe in is set at 1/32" as iapexl8r had stated this for his use, and from another couple of GT500 guys with that setting for both track and on the roads.

Castor is funny... some run +7° and +6.5° for roads. So I figure +7° castor and deal with road tilt. Ha!

-1.5° is max camber for many road driven Mustangs. I figure I will try -2° as a starting point and have a quick setting for -3° and -4° for track.

Will update my info so I don't go off by using my noodle. Ha!

Thanks for all your moments, as it shows how far one can go and still keep the sporty feel without much compromise.
71 Javelin SST body
390 69 crank, 70 block & heads
NASCAR SB2 rods & pistons
78 Jeep TH400 w/ 2.76 Low
50/50 Ford-AMC Suspension
79 F150 rear & 8.8 axles
Ford Racing 3.25 gears & 9" /w Detroit locker
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Post Options Post Options   Thanks (0) Thanks(0)   Quote shootist Quote  Post ReplyReply Direct Link To This Post Posted: Jul/27/2017 at 11:48am
From my understanding, through talking with my alignment guy (he setups up road course cars for rich guys). Caster has most impact on the go straight, return to center, high speed stability and helping correct for bump steer effects by aligning the tie rod end travel in a better geometry with the suspension travel. I think that may also be why you see such a large variance on caster as it is less critical for street and track manners. Now toe on the other hand is going to have major impact on how the car handles from responsiveness (oversteer or understeer). If you want to just think about turning the wheel and immediatley start taking a corner set the toe out. If you want to have streetable ability to drive with your knee set the toe in. As far as the camber goes, I think you will find that has the most profound effect on holding the corners. Anyway, I wouldn't get too caught up on caster provided it works like you want it to in the previously mentioned areas and rather focus attention more on toe and camber for tuning the performance how you like.

Oh I think I figured out my tires sizes. It looks like I will go 18" wheels since the tires selection is better as well as the pricing. I am looking at one of these 4 for the back. 255/45-18, 265/45-18, 275/40-18 or 285/40-18 depenging on how much meat I can fit in the stock wheel well since getting rid of the leaf springs. I haven't yet calculated the front but it will likely be a 225-255 up front. I will likely keep a set of 225 harder compound for the front for everyday tooling about on the street and change over to a softer and wider tire for track days.


Edited by shootist - Jul/27/2017 at 12:01pm
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