ALFAGTV6.COM

Mats · Post by **Mats** » Sun Nov 18, 2007 1:10 pm

It's because different tires need different camber. V8 supercars doesn't have the same tires as I have I bet and they certainly doesn't have the same tires as the F1 boys so any cross-the-borders comparison will ever be valid.

kevin · Post by **kevin** » Sun Nov 18, 2007 1:25 pm

After this season I have learnt something(not much though) about camber and that is every transaxle car is different. For example my car weighs in 1200kg runs 2.8 deg camber, 3deg castor and 1mm toe in. After each race I compare my tyre wear with my mates Giulietta and his tyres have near perfect wear across the front tyres while mine are pretty shot on the outside and new on inside. He only runs 2deg camber but his car weighs 400kg lighter than me. Also his chassis rigidity is superb due to his roll cage design so his suspension really works. I did mention he is quicker than 911 RS Porsches as well. This Giulietta I believe is the ultimate track car running at the moment and also won a few stages on the all tar rally a while ago so it can also handle the rough stuff(average tar road). Due to his low cambers and weight he also outbrakes most of the all of the entrants. (I will still post full specs of this car with pics of its lower control arms)
Grant , check your tyre wear and let us know. Maybe next year I might learn a little more.

grant · Post by **grant** » Sun Nov 18, 2007 3:56 pm

Hey Kevin,

If you look in the introduction forum, I posted a picture of my car going around a medium hairpin. It's obvious I have positive camber and am probably losing grip here. It makes sense, because for this turn, the understeer was greater and my grip felt less than on the other turns.

I only have 27mm torsion bars so my chassis rolls a lot. My camber settings most liekly won't work for you. You really should buy an infared pyrometer (like $40 US?) and take a look at the temps. If it is more than 15 degrees hotter on the outside overall all than the inside of the edge of the tire, there isn't enough camber and you could be gaining some grip here.

The caveat is, as you know, that sometimes the best tire temperatures don't = the best lap times because you need to have a flat tire on the road to get the most braking force.

Similar thinking works for the rear tires in the case of acceleration. My hunch is that for me, I should be running around 3.5-3.8 degrees of camber for the best lap times on a medium speed road course, but my car is a daily driver so the tires have to last.

la_strega_nera · Post by **la_strega_nera** » Sun Nov 18, 2007 4:35 pm

Mats wrote:It's because different tires need different camber. V8 supercars doesn't have the same tires as I have I bet and they certainly doesn't have the same tires as the F1 boys so any cross-the-borders comparison will ever be valid.

I dragged the V8 supers up because they're a similar sort of weight to some of the heavier 75s, run slicks that aren't particularly exotic, and are a good example of something that works while being setup fairly soft.

junglejustice wrote:Oh boy - here comes another "hand on cock" comment - I can feel it...

I guess that all of the F1 teams must "run alignments to get around compromised geometry"...? Ben - ever have a good look at an F1 car's front end!? Not even close-up - just ANY F1 footage - have a look at the MASSIVE negative camber on those cars! Why? Their cornering appears to be 100% flat and they arguably have PERFECT roll-centers (by design any way...)

Why the extreme -camber then?? Because they run "a geometry that actually doesn't work"...? Wanna tell me that your builders of "Australian V8 supercars with scratch built frontends" know something that the F1 boys don't?

Yep. The v8 supers guys do know something the F1 guys don't. They know how to get a relatively heavy sedan to go round corners on cheap (comparatively) low profile slicks with not alot of downforce. F1 cars weigh less than half the AVESCO cars, make 50% more power, generate huge downforce, run tires that are an order of magnitude more expensive, run on billiard table smooth tracks, and are setup so stiff that they don't even have conventional pivots on the inner end of the arms anymore. Suspension design is no longer important in those things, just more downforce. So, yeah, F1 is clearly relevant. Might as well look at drift cars too.

Post by **Zamani** » Sun Nov 18, 2007 4:54 pm

Grant,

-4 degrees of camber? Are you kidding?

grant · Post by **grant** » Sun Nov 18, 2007 4:55 pm

Nope. I say this because in the pictures I've seen of my car cornering hard, I could be benefitting from more camber with my SOFT setup. Obviously 30mm T-bars/RS Kit will change this.

Also, stickier tires will make my roll even worse. I can't say for sure, but I think optimal for me would be greater than 3 degrees.

What do you think? I think Jes is on the right track too, but pyrometer blah blah blah.

Mats · Post by **Mats** » Sun Nov 18, 2007 10:59 pm

Ben: I don't see how there is even a remote way to compare slicks to "R" compound tires, the carcass is completely different. But I sort of see your point anyway.

grant: Infrared pyrometer suck and should not be used on tires, you need a probe type meter or you won't get accurate readings.
Also you need more caster for a start, as much as you can get, this will give you quite a bit of camber change in those hairpin turns.

la_strega_nera · Post by **la_strega_nera** » Sun Nov 18, 2007 11:32 pm

Mats wrote:Ben: I don't see how there is even a remote way to compare slicks to "R" compound tires, the carcass is completely different. But I sort of see your point anyway.

I dragged slicks up because they grip they generate generally results in people feeding more negative camber in to deal with the extra roll that is generated...
My (unclear) point was that the camber numbers being talked about seemed more the realms of the slick shod cars.

grant · Post by **grant** » Mon Nov 19, 2007 6:03 am

Mats, I'm only running 1.3 degrees caster - no space behind the 225/45/16 tire to lean it back much. Sucks huh?

Mats · Post by **Mats** » Mon Nov 19, 2007 6:27 am

Make room.

grant · Post by **grant** » Mon Nov 19, 2007 7:46 am

This is where I confess I'm in the wrong thread - I'm not putting a sledge hammer to my street car

Giuliettaevo2 · Post by **Giuliettaevo2** » Mon Nov 19, 2007 2:15 pm

On my street Giulietta i run 6.5 degrees of castor, 0.5mm toe-in and 2.5 degrees camber...castor is set to the max with the balljoints off a 105series. The front end is lowered and the rear has 75 lowering springs of unknown origin. yellow koni's all around ( fully closed on the back, 3/4 closed up front)and a 28 mm stabilizer up front. This is quite a harsh ride but it handles beautifully! very neutral with a touch off oversteer if you push to hard.

GTV27 · Post by **GTV27** » Sat Dec 08, 2007 3:16 pm

Lots of historic racers (ie dudes being forced to make the best of compromised geometry in order to go fast) end up running as much as 4 to 6 degress negative on the front with r- spec tyres.

Check RS 1600 escorts, XU1 Toranas, have even seen some big Falcons with wild cambers (Ben???)

It not ideal but its all a compromise in some respect. Obviously these cars don't cruise down the highway too often, so wear is not a factor, just grip for turning.

As it applies to GTV6 world, I am coming to the conclusion with mine that unless geometry changes are made, its going to savage its shoulders. I've gone up massively in spring rate (28mmtb and 200lbcoils), front AR bar size (24mm, now back at 22mm to get it to turn) and put the camber up (from 1.5 to 2.5 - still a road car

) and it will still get onto (and overheat) the shoulders. I even lifted the front end up so the LCRs are flat to get a better camber curve, still eats its tyres

.

Partially, I think this is due to the higher CoG of the V6 (sorry, no numbers just gut feel) compared to the 4 cyl.

As to those that say just stiffen it - I can't imagine running harder spring rates on the road and not killing the body shell, so that's not happening.

What I'd really like is for Yokohama to bring back the A008rs tyre - that could deal with all sorts of stupid geometries and still grip and wear OK.

la_strega_nera · Post by **la_strega_nera** » Sat Dec 08, 2007 6:25 pm

GTV27 wrote:Lots of historic racers (ie dudes being forced to make the best of compromised geometry in order to go fast) end up running as much as 4 to 6 degress negative on the front with r- spec tyres.

Check RS 1600 escorts, XU1 Toranas, have even seen some big Falcons with wild cambers (Ben???)

Because of the aspect ratio rules I'm setting the falcon up for Cross ply Hoosier TDs/Goodyear Bluestreaks, which means less negative camber... I just can't get enough rubber under it in radials... Yoky A032s or 48s in 225/60/15 aren't going to cut it for long with 550hp and 1500kg, the crossplies I can go up to 275/60/15 on the back... (cheaper too!)
I've tweaked the front end geometry to try and help too (within the rules!). More camber gain, less anti dive. Wheel rates are around 180lb/in on the back, 250ish on the front, big bars at both ends (because of the detroit locker type diff, setting it up softly sprung but with a decent roll bar at the back unloads the inside rear to reduce the understeer. not a problem with a real LSD)

When it comes to stiffening the suspension right up, there comes a point where the bodyshell flex becomes an issue and the car stops responding to changes in the suspension setup. Of course, with a good cage stiffening the shell this is less of a problem.
If anyone ever buys this bloody ford off me, you guys might see something neat to fix the front end geometry

Ben

GTV27 · Post by **GTV27** » Sun Dec 09, 2007 4:41 pm

I have had some experience on Hoosier Street TDs on Dad's XU1 (also has a detroit locker) and they are a fun tyre to drive on. A very wide range of acceptable slip angle so lots of big long power slides.

When he went to radials (Toyo RA1) we had to take it from about 1.5 deg to 4 deg camber. It was a lot faster, but not nearly as nice/easy to slide around.

Hope you sell the Falc soon