Positive Camber For Drags

[The Bogan]

G,day, Im after some knowledgable info.

Car is a R33 GTST running M/T Street radials, with my "drag suspension" (stock shocks w/ standard height springs) installed in the rear the car has been raised about 50mm and has given me around 1 deg positive camber (roughly using a straight edge and calibrated eye).

As it is a IRS car would this be fine to get near a 0 deg camber when it squats on launch.

I know there is more to it than rough numbers but really all Im after is a good starting point and then start adjusting from there.

Thanks, Mark.

[R31Nismoid]

I remember a thread on this semi-recently, in the past 4 months for sure.

I've had a bit of a search, but can't remember where it was. Someone else was asking much the same question. I'll keep looking and see if i can find it, was a few posts on the topic but i think it was in the middle of another discussion

[The Bogan]

I remember a thread on this semi-recently, in the past 4 months for sure.

I've had a bit of a search, but can't remember where it was. Someone else was asking much the same question. I'll keep looking and see if i can find it, was a few posts on the topic but i think it was in the middle of another discussion

I found a few but all they said was to get to 0 deg camber on squat, not what you could start around, on a yank site there was talk of 0.5 positive but that was on drag specific shocks and springs on a new Camaro.

Its a pity but I assume that people are not to keen on giving up their "secret"alignment settings they most likely spent along time working out....

[R31Nismoid]

Nah there was definitely talk of positive camber at the start.

I had a search for about 15mins but couldn't find it, pretty sure it was a side convo in topic about something unrelated

[MBS206]

Mark, you need to figure out a method to measure how far your car is actually squatting on launch.

From there, strap the car down so the suspension is compressed down that far. I'd then set the car up to still have the MINUTEST touch of positive camber.

You should then be pretty darn close to 0 when you actually launch it. As you'll have more grip then you currently have, it'll squat the slightest bit further, and that previous minute amount of pos camber becomes 0 camber.

[The Bogan]

Where I am ATM, best 60ft was 2.1

Installed stock shocks with heavy duty standard height springs, measured camber which came to positive 0.75 deg, as my camber was set at 0.75 neg on my Bilstiens w/ low King springs it is a change of 1.5 deg.

Car was raised from 340 to 380 at the rear, 40mm more height so hopefully the Drag radials will not hit the guard now.

If this doesnt work Im going to replace the low King springs for the heavy duty springs in my Bilstien shocks and set the shocks at the heighest setting.

Trying to get the car set up for the drags by just replacing the struts so I can have my normal street/track struts and my drag struts as the only thing I need to change, I can see this not working well though and a couple of trips to the tyre shop for re/re alignments between drags and circuit work.

ATM my main concern is getting the car set up for the SAU NATS airport run, weather permitting Ive got 4 Wendsday night drag days to get my sorted on.

Hopefully my 60 ft gets better and I can drop my times.

RWDFTWBBQ

[MBS206]

Just thinking about it, put it on a wheel aligner mark, pull the car down (Strapping the rear down only) until your tyres touch the guards. Then slowly release the straps until you're 30mm off the guards. Set camber to 0 degrees at this point.

You were previously squatting hard enough to touch the guards, you've now raised 40mm, so allow an extra 10mm for further squat.

See how you go.

[kil-351]

a lot of this is going to depend on the front / rear coil over spring rates and how the shock holds / releases weight... if youre planning on playing with what you have then you will need to launch the f**k out of your car and make adjustments at both ends till you find a sweet spot for your set up till you cant go faster.. tyres will play a massive part too

[R31Nismoid]

^ yep, it's about how the actual shock behaves that you need to worry about more than this camber quest IMO.

Bilsteins in my two experiences with them, are not good for drag activities as they are quite hard and raising might not help all that much. If you go any higher the rear will be sitting even higher in the air and having the weight starting front heavy rather than at least even to transfer backwards.

[34GeeTeeTee]

Wouldn't you be messing with the Toe settings as you go up and down in height? Doesn't that affect traction a bit?

[The Bogan]

My problem is that I purchased some R32 GTR rims with 255/50 16 M/T ET Streets which do not fit well inside the guards (I believe the cool kids call it hellaflush), when the tyre hook up it makes the outside edge of the guard hit the tyres, My conclusion to fix this for now (I will end up getting some 16 x 8 rims with a better offset) is to raise it up a bit to give it better clearance for now, I tried to overcome this initialy but fitting some standard shocks but although it got me to a better height the valving in the old stock shocks was arse.

Ive raised the front up one groove on the Bilstiens, which now has it at the heighest settings front and rear, I shall then lower the rear down one groove at a time over the next couple of weeks to try and find the sweet spot for the clearance I need.

ATM front is 345 and the rear (after some settling) is 370, as the Kings were progressive springs and the new ones are not so the squatting shouldnt be as aggressive due to the new springs not being as compliant in the first stage of compression..

The boat will go in for a wheel alignment on Monday to ensure Im on a level playing feel after all the playing around with the ride heights, Im going to get the camber set to 0.5 positive at the rear.

I will see how it goes on Wendsday night weather permitting.

[The Bogan]

Did a 11.6 at WSID, 0.3 faster than last time, best 60ft was 1.9, now its time to keep working on my RPM at launch to try and find the sweet spot, I never managed to find the right RPM tonight, 4000 wasnt enough but 4500 was to much.

Finding the happy medium is not such a easy process, for me anyway.

I did get to watch a S chassis 2ltr manual do a 9.? though, it was fast.

[SRS13]

Didn't see you there last night.

Not sure on what method you used and I'm no expert but revs are one thing and how you release or slip the clutch is another. If you simply 'dump' the clutch at 4500rpm it will lead to wheelspin (in your case), but if you slip the clutch out it wont send all power straight to the wheels and allow a better take off. Just about practise really as its hard to get right.

I managed to get my 60 foot down from 2.4 first pass down to 1.8 on 15" 215 re-mould tyres on the same night (this was a few years back mind you).

[2rismo]

1deg+ is a good thing. If you're running a street R33 GTST on 255 MT ET Street Radials with a 5-speed then you should be aiming for the high 1.5 - low 1.6sec 60ft region. What pressure do you have in the tyres?

[The Bogan]

1deg+ is a good thing. If you're running a street R33 GTST on 255 MT ET Street Radials with a 5-speed then you should be aiming for the high 1.5 - low 1.6sec 60ft region. What pressure do you have in the tyres?

I started at 17psi then went down 1 psi per run, best 60ft was at 14 psi, I went down to 12psi but my 60ft got worse, more likely my technique than the tyre pressure though..

Alot of my issues has to do with being consistant, trying to get my launch RPM, clutch slip, tyre pressures the same to get some usefull information is fairly tricky, with a heap more seat time and playing around with the settings should help me whittle my times down a bit by bit.

Thanks, Mark

[MBS206]

1deg+ is a good thing. If you're running a street R33 GTST on 255 MT ET Street Radials with a 5-speed then you should be aiming for the high 1.5 - low 1.6sec 60ft region. What pressure do you have in the tyres?

Needs more Auto...

[2rismo]

I started at 17psi then went down 1 psi per run, best 60ft was at 14 psi, I went down to 12psi but my 60ft got worse, more likely my technique than the tyre pressure though..

Alot of my issues has to do with being consistant, trying to get my launch RPM, clutch slip, tyre pressures the same to get some usefull information is fairly tricky, with a heap more seat time and playing around with the settings should help me whittle my times down a bit by bit.

Thanks, Mark

Let me know next time you're heading out to race. If I'm around I'll poke my nose in and see if I can help.

[The Bogan]

Let me know next time you're heading out to race. If I'm around I'll poke my nose in and see if I can help.

Thanks mate, Im in the process of getting my Link ECU tuned up with launch control, hopefully that will make at least 1 thing easier, all I need to do is work on the other 300 things to do to get some good times.

I did manage a 1.604 on the 24th, most were around the 1.7 - 1.8 though.

Cheers, Mark

[Dobz]

You need front shocks that are set up on a "90/10" ratio. I'm no expert on the matter but from what I understand the shocks draw out easily to transfer the weight to the rear wheels when launching. The shock then has a slow compression to help keep the weight on the back as you accelarate.

[The Bogan]

11.130 @ 130.45mph, 1.779 60ft

Camber was 0.5 deg positive with 0 toe

12 psi in the tyres

So far so good, only had 2 runs tonight as I blew a cooler hose near the turbo, it was to hot and to much bother to try and fix it there.

Next week Im hoping for even better.