27 replies to this topic

[Sphinx]

I am doing a winter set up and am starting from scratch due to new offset bushing, west coast tires (Toyo), etc.

 

Using JD 'sguide, I started out with a baseline set up: right height, camber, caster, and toe.  Next, I scaled but end up with a cross weight of 43.XX% (RF+LR).  So, per the setup guide, adjusted only the RF & LR adjusters till I got to 49.8%. 

 

Was it wrong to only adjust those two?  Now that the car is scaled, I imagine I should just reset ride height by adjusting perches equally to drop the entire car down to 4 5/8" - right?

 

And now it is time to chase the alignment, yet again.  All camber settings are now off by about .5 degrees.

 

Does this sound like I'm on the right track or am I missing anything?

 

 

[chris haldeman]

Yes it was wrong to adjust only the 2 perches. In order to maintain a mostly level ride heights you need to adjust all 4 corners. Start over by setting the car level at the ride heights you want. Then set camber then set toe. After all that roll the car and check cross. If cross is below 50% adjust the RF and LR up and LF,RR down in equal amounts until desired cross is reached. Car should maintain mostly level and cambers should not change much. After it is close then re check everything and creep up to perfect. The first major set up on a car from scratch is a huge pain in the butt

[davew]

Every change effects every reading. Go through and set everything close tho what you want. Then start fine tuning, but always go back and take all the measurements after any change.

 

get ride height and cross close. then set camber, then recheck/adjust ride height and cross. Then reset camber if needed. Then recheck and adjust ride height and cross. Wash rinse and repete if needed.

 

An experienced set-up guy can do multiple steps based on experience. Take your time and do one adjustment at a time. Understanding what you are doing and why will be less frustrating than trying to do multiple adjustments. As you gain experience, you will be able to do multiple adjustments.

[Sphinx]

Thank you both.  Almost done!

 

Here's what I did:

 

With the car balanced, I dropped each perch by two turns (to get it to 4 5/8" at the lowest corner; the others weren't significantly off after the drop).  The camber came back on the fronts, toe is perfect.  The rear camber was was slightly off.  A little adjustment and all's well.  So, I did in two steps what you guys are doing in one. Ended up with 49.98%.  Yeay!

[MazdaSteve]

Sphinx, do you have the car loaded with ballast to simulate your weight in the driver seat?

[MazdaSteve]

And sway bars disconnected?

[Sphinx]

Sphinx, do you have the car loaded with ballast to simulate your weight in the driver seat?

 

Yes, a 7 year old, 50#'s of lead and some old rotors got me there.  Didn't need much ballast though.

 

And sway bars disconnected?

 

Definitely.

[Bench Racer]

Yes, a 7 year old, 50#'s of lead and some old rotors got me there.  Didn't need much ballast though.

70 pound sand bags (adjusted for driver/gear weight) work well with 20 pounds of lead at foot heal location, a bit anal, Ya.

 

One of my father/son friends (using term loosely Danny) insisted driver son sit in car, to which I finally said, give me a friking break. They now use dead weight, same as when driver was in place.

[av8tor]

Thank you both.  Almost done!

 

Here's what I did:

 

With the car balanced, I dropped each perch by two turns (to get it to 4 5/8" at the lowest corner; the others weren't significantly off after the drop).  The camber came back on the fronts, toe is perfect.  The rear camber was was slightly off.  A little adjustment and all's well.  So, I did in two steps what you guys are doing in one. Ended up with 49.98%.  Yeay!

Really, you are going to accept 49.98%.  Glad you are not my pilot.

 

Just kidding

[38bfast]

There is not a track that we go to that we run at 50% cross. At the runoffs this year we were close to 52%. We would have put in more but then wheel spin is a issue.

[Jim Drago]

There is not a track that we go to that we run at 50% cross. At the runoffs this year we were close to 52%. We would have put in more but then wheel spin is a issue.

 

Other than Mid Ohio.. I bet I run 95% of all my races between 49.8 and 50.7%.. two National Championships were won between 49.8-50.2% 

 

For the beginner,  setting the car at 50% and running will be a very good start and will get him/her 90% of the way there while learning the car. That is what I would suggest so they don't get overwhelmed and adjust themselves out incorrectly. That and watch toe and tires pressures, much more so than cross at first.  Set the car pretty square and high enough to be off the stops for the most part.

 

 IMO, a good driver can run within a few tenths of his best lap with a car set at 50.0% at every track less a very select few.  May not be able to do as many as the car will go away. 

 

Many would be VERY well suited to start here and leave it alone and just check for movement.. 

 

Cambers.. 3.5 front, 3.25 rear

caster front +5.5

toe front 3/32- 1/8 inch out

toe rear 1/16-1/8 inch in

ride heights to bottom of rocker..  front 4 5/8 - 4 3/4

49.8-50.2 % cross

[FTodaro]

I would agree with Jim, my only addition would be, i found running big RR camber a the runoffs with the cross was to much for me, i was getting to much RR tire lock up at the end of the back straight. I know there is a solution for that which i chose not to use but had i taken some of that out i think i would have had a better car. You do not need big RR camber at mid o, for turn 1 for example. That was my thought.

 

I also agree when I first learned how to do a set up i was over thinking it. I think you can get a base line and run most of the tracks with out significant adjustment especially in cambers.

[Jim Drago]

I would agree with Jim, my only addition would be, i found running big RR camber a the runoffs with the cross was to much for me, i was getting to much RR tire lock up at the end of the back straight. I know there is a solution for that which i chose not to use but had i taken some of that out i think i would have had a better car. You do not need big RR camber at mid o, for turn 1 for example. That was my thought.

 

I also agree when I first learned how to do a set up i was over thinking it. I think you can get a base line and run most of the tracks with out significant adjustment especially in cambers.

That was primarily due to the cross( best guess 95% cross and 5% camber IMO). There is no weight on that wheel as we had so much cross and the straight is off camber in braking zone.  I fixed that on my car with a far less agressive pad on RR. Problem solved. That was an old Saul Speedwell trick that works well when running high cross.  "give the car what it wants" 

[Parity]

  "give the car what it wants" 

What if it want a better driver? 

 

Jim, seems like cross and height are the main concerns. What about front/rear, left/right balance? Do you try to get them close or just look at cross/height?

[davew]

What if it want a better driver? 

 

Jim, seems like cross and height are the main concerns. What about front/rear, left/right balance? Do you try to get them close or just look at cross/height?

 

You can not vary the LR or FR percentages with the spring collars. To get enough adjustment would require HUGE ride height variances. When you play with cross, you move weight diagonally not front rear or left right

[Jim Drago]

What if it want a better driver? 

 

Jim, seems like cross and height are the main concerns. What about front/rear, left/right balance? Do you try to get them close or just look at cross/height?

 

As far as balancing front to rear.. I dont bother with that at all as that changes with rake.   I do try and balance left front to right front and left rear to right rear. That is very much dependent on driver and amount of ballast in car. In cases with a driver 180 or less.. we can get left and right wheels easily within 10 lbs or so without compromising ride heightsmuch at all if any.  On heavier drivers like yours truly with no ballast.. I am always heavy on the left side.. I usually try and worry more about matching fronts than rears.  

Jim 

[B(Kuch)Kucera45]

Always make sure you never put your drivers weight weights in the trunk because you might forget them and trust me the car doesn't sound or handle good with 170lbs sliding around in the trunk.

Don't ask me how I know this !

[Ron Alan]

For those who have done lots of detailed data analysis...at what point does camber(too much) truly affect braking(too little tire patch)? 

[Jim Drago]

Always make sure you never put your drivers weight weights in the trunk because you might forget them and trust me the car doesn't sound or handle good with 170lbs sliding around in the trunk.
Don't ask me how I know this !

Several years ago I sold a car and when I asked the customer what they thought after the first session... they said the hp was good but felt it was down 1-2 ft lbs of tq coming out of corner.. I told them to bring it down so I could take a look and noticed an upward dent in the trunk... I popped the trunk to find their spare transmission I told themtheir two ft lbs was probably the trans in the trunk .. they ran the entire first session that way and had no idea. There was no more talk of power after that 😄

[Sphinx]

Interesting on the rear camber.  JD recommended 2.5 degrees on the rears.  Is your recommendation for a 3.25 baseline the same on a 1.6 v. 99+?

 

 

Other than Mid Ohio.. I bet I run 95% of all my races between 49.8 and 50.7%.. two National Championships were won between 49.8-50.2% 

 

For the beginner,  setting the car at 50% and running will be a very good start and will get him/her 90% of the way there while learning the car. That is what I would suggest so they don't get overwhelmed and adjust themselves out incorrectly. That and watch toe and tires pressures, much more so than cross at first.  Set the car pretty square and high enough to be off the stops for the most part.

 

 IMO, a good driver can run within a few tenths of his best lap with a car set at 50.0% at every track less a very select few.  May not be able to do as many as the car will go away. 

 

Many would be VERY well suited to start here and leave it alone and just check for movement.. 

 

Cambers.. 3.5 front, 3.25 rear

caster front +5.5

toe front 3/32- 1/8 inch out

toe rear 1/16-1/8 inch in

ride heights to bottom of rocker..  front 4 5/8 - 4 3/4

49.8-50.2 % cross