Guldstrand Mod Templates

[Rod]

Rodney, can you place an angle finder on your control arm shaft with the car on it's wheels?
By the way, my template shows a rearward move of .200" I think they would have moved them more, but the rear bolt head would hit the flange. To get 5 degrees caster with no shims would require around 7/8" move which would be beyond the bracket, or on the edge of it. The A arm may contact the bracket on the front side also.

I will do that in the morning, I will do it both on Plain Jane and Suzys car...and post a picture....ugly betty hasnt had the mod done, waiting on products to show the full Ugly Betty build

[David Pozzi]

the factory suspension has a positive camber gain (the wheel actually angles out at the top when compressed or turning) a tall .500 ball joint just barely gives you a neutral gain (you have neither positive or negative within a certian range) so you can run the tall ball joint (.500) and the guldstrand together ,,,,the (ridetech/Fatmans) tall spindle and standard ball joint just moves the gain into negative and that helps more than the tall ball joint, so you dont "need" to do the guldstrand with the (ridetech/Fatmans)tall spindle, but to have an aggresive gamber gain (like a C5 corvette) you can run both the ridtech/fatmans spindle and the guldstrand.............the reason i have to point out that spindle, is that some "TALL" spindles like the cpp spindles are not as tall as the ridetech/fatman spindle ....the speedtech/ATS spindle is taller than CPP and shorter than the Ridetech/Fatmans spindle, so with the Speedtech/ATS spindle to get a good curve I also used a .500 tall ball joint and it was better than the (ridetech/Fatmans) by itself and almost like the (ridetech/Fatmans) and guldstrand together.....thats just what i have tested and raced with

hope that helps

One thing that I've run into is going to a drop spindle lowers the angle of the upper A arm so camber gain is greatly reduced.
Stock suspension has a camber curve when plotted out. If you start out at zero camber at what I call "normal ride height" "N", then push the wheel up an inch at a time, you will have camber gain measurements. As you go up from "N" camber increases more at each step. On a stock first gen, it can go positive the first inch, then start going negative more and more each step. You can install a 1" taller upper ball joint and the camber will increase more rapidly, a good thing. You can then install a 1" tall lower ball joint and this would lower the front 1", so you need to raise it back up to "N" height by shimming the springs. NOW your 1" taller upper ball joint is at a height that a stock upper ball joint would be. This change places the upper control arm at a flatter angle and there will be less camber gain, closer to what a stock camaro would be. There is a little benefit from the tall lower ball joint, but it is in roll center geometry, almost no help in camber gain. So in a 2" drop spindle, you have to make the top of the spindle at least 2" taller to keep the upper control arm at the angle it would have been stock. And, we know the stock UCA angle is not that great for generating negative camber. The drop of the spindle takes away upper A arm angle.



Any camber gain charts you see need to be starting at the same ride height or they will be difficult to compare.

[Rod]

One thing that I've run into is going to a drop spindle lowers the angle of the upper A arm so camber gain is greatly reduced.
Stock suspension has a camber curve when plotted out. If you start out at zero camber at what I call "normal ride height" "N", then push the wheel up an inch at a time, you will have camber gain measurements. As you go up from "N" camber increases more at each step. On a stock first gen, it can go positive the first inch, then start going negative more and more each step. You can install a 1" taller upper ball joint and the camber will increase more rapidly, a good thing. You can then install a 1" tall lower ball joint and this would lower the front 1", so you need to raise it back up to "N" height by shimming the springs. NOW your 1" taller upper ball joint is at a height that a stock upper ball joint would be. This change places the upper control arm at a flatter angle and there will be less camber gain, closer to what a stock camaro would be. There is a little benefit from the tall lower ball joint, but it is in roll center geometry, almost no help in camber gain. So in a 2" drop spindle, you have to make the top of the spindle at least 2" taller to keep the upper control arm at the angle it would have been stock. And, we know the stock UCA angle is not that great for generating negative camber. The drop of the spindle takes away upper A arm angle.

Any camber gain charts you see need to be starting at the same ride height or they will be difficult to compare.

well said...how do you explain it better then me

I just ask myself "What would Mary say?"

[dondb]

David, What numbers are you suggesting for the front bolt hole down....1.060 or .875? In a previous post you said to use the later template....Is it yours on your web site, Rodney's or somewhere else??? I'm going to do the mod this weekend and would like to do it right.

Below is from your website:

My measurements off my template are lower ft bolt 1.060" lower rear bolt .775" To measure, draw a line through the top hole centers, the cross hairs are accurate reference points, the circles are a bit off center so don't use them. Measure down from this line. The lower holes are also offset 1/4" to the rear to increase positive caster adjustment. My template was aquired by me when I visited Guldstrand sometime arond 1973, I talked to an engineer there who said they developed this template for Penske. My version shows some alternate holes that were tried, these holes were higher and lower than this "final" version.
NOTE Chicane67 was an employee of Guldstrand Ent and says his hole lowering measurements are: F .875" R .775"

[David Pozzi]

David, What numbers are you suggesting for the front bolt hole down....1.060 or .875? In a previous post you said to use the later template....Is it yours on your web site, Rodney's or somewhere else??? I'm going to do the mod this weekend and would like to do it right.

Below is from your website:

My measurements off my template are lower ft bolt 1.060" lower rear bolt .775" To measure, draw a line through the top hole centers, the cross hairs are accurate reference points, the circles are a bit off center so don't use them. Measure down from this line. The lower holes are also offset 1/4" to the rear to increase positive caster adjustment. My template was aquired by me when I visited Guldstrand sometime arond 1973, I talked to an engineer there who said they developed this template for Penske. My version shows some alternate holes that were tried, these holes were higher and lower than this "final" version.
NOTE Chicane67 was an employee of Guldstrand Ent and says his hole lowering measurements are: F .875" R .775"

.875"F & .775"R & .200 rearward. Which Chicane 67 recommended is the most reliable source. He worked there when he got it. It isn't that different from mine, so you could use either one and not notice the difference in my opinion. The yellow sheet seems to say .75" drop, which is less, and I think the Guldstrand mod is already a little conservative, so it doesn't seem as attractive to me. You could easily use the Guldstrand mod with a .5" tall upper ball joint and stock lower BJ - stock height spindle. That is how conservative the drop is.

[dondb]

Thank you David. I currently have the level 2 Hotchkis TVS system on my car. I am going to do the G Mod, and install the hybrid Viking front double adjustable coilovers, and the Tru Turn system. For now i'm going to leave the Hotchkis rear leafs and put in the viking smooth shocks to match the front shocks. I'm going this route because the front was about 1/4 to 1/2 inch different between the driver and passenger side.....not to mention the car rides like a buck board. I appreciate your clarification on the measurements!

[Rod]

Rodney, can you place an angle finder on your control arm shaft with the car on it's wheels?
By the way, my template shows a rearward move of .200" I think they would have moved them more, but the rear bolt head would hit the flange. To get 5 degrees caster with no shims would require around 7/8" move which would be beyond the bracket, or on the edge of it. The A arm may contact the bracket on the front side also.

placing it on the cross cross-shaft




angle finder on the cross shaft

[ryanleiker]

I'm about to finally pull the trigger on this...

Will I be using stock alignment specs?

*Also... I am now currently using CPP C5 spindles... which, according to my measurements are 1" taller than stock... so will probably end up with stock height ball joints.

[Trinity]

Anyone got a true to scale template I could get. Emailed guldstrand motorsports 3 weeks ago and still have not gotten a response

[David Pozzi]

Best bet is to draw your own. Mine is a photo copy, if I copied it and sent it to you, it would be a copy of a copy and not very useful.
What I did was take my copy and verify the hole spacing between the A arm hole centers. If that's a little off, the bolts won't go through correctly.

Also in drilling the holes, start small and work up. Center punch the holes well and get the drill lined up straight so it doesn't wander. A 7/16" drill bit is .4375" but they often drill .003" oversize.

[dusterbd13]

Necrobump!!!

Is this applicable to both forst and second gen f bodies? I believe it os, but want to make certain before applying it to my 80 firebird build.