Help me out. MKII and SAI kit?

[Cobra Cory]

Do I still need the bump steer kit when using the SAI kit from Whitby's.

[johnny camp]

Are you racing or is it just for street use? I am happy with the sia mod and breeze's offset rack bushings to center the rack. Seems to handle pretty neutral. My car is only street driven (although sometimes spirited).

[CRZN 427]

I have a MK-II also and was lead to believe a long time back that the SAI kit was not needed on that chassis design.

The bump steer kit is something entirely different and may well be of benefit to you. I made up my own way of doing the bump steer, but I have not driven the car yet to know if it is any good.

Regards, Rick.

[Cone Basher]

The SAI mod has to do with centering the steering axis closer to the center of the front wheel. It does a great job of eliminating the "twitchy" feeling you get as you car gains speed. The bumpsteer mod deals with a different aspect. The bumpsteer mod is used to reduce the toe change you get under braking or anytime the front wheels move up or down. Basically how it works is to bring the LCA and the steering arm as close to parallel as possible, some builders have added rack extenders to help this problem. If these two links are not parallel the upward or downward motion of the front wheel induces a toe out or toe in condition depending on the angles. It's very scary t runinto a fast corner nail the brakes and have your car dart left or right due to a bumpsteer problem. If it was me I would consider bumpsteer as part of a package to get the best handling possible.
Try this:
1)go to google and type the following:
2) site:ffcars.com bumpsteer mod or anything else you want info about
If you go there you can find a number of diagrams that expain SAI and bumpsteer. Best search I discovered late in my build.
HTH
CB

[Cobra Cory]

I have a set of Forte's bump steer pieces on the car already. Just wondering if I needed it for the SAI. My car is really twitchy on the highway and was told that the SAI kit will improve the handling even on a MKII. Hope I'm right.

[Cobra Cory]

Wow we both wrote in at the same time and both used the word Twitchy....

[Dan Babb]

Paul....Have you checked all the suspension bolts on the upper arms?

I brought my car in for a required tech inspection before a track event a few months ago and a number of the bolts on the front suspension had come loose. Not a lot, but enough that the tech guy could wiggle the front wheels.

[Cobra Cory]

Yeah Dan, Mine are all fine. But I am switching all the bolts out to the Cobra Cory front suspension bolt package I made years ago when people were showing bolts with no threads showing past the nuts. I still had a new set of bolts left and figured I might as well use the new bolts as I am taking everything off anyway to clean things up.

[CraigS]

You mention MkII and SAI but don't mention which spindles you have. If you have sn95 you can do the SAI mod. If you have Fox like most MkIIs, you will need to do some work first. Whitbys can machine the upper balljoint hole in the SAI adapter 5/16 deeper and that will get the balljoint inside a 17x9 Bullit wheel. Then you use the adapter only and not the frame bracket but you will need longer tubes on the UCAs.

[John Baker]

Originally Posted by Cobra Cory

I have a set of Forte's bump steer pieces on the car already. Just wondering if I needed it for the SAI. My car is really twitchy on the highway and was told that the SAI kit will improve the handling even on a MKII. Hope I'm right.

What ratio steering rack are you using?
If it is 2.25 turns lock to lock you might be able to save some money and hassle on the SAI mod just by replacing the steering rack with a slower 3 turn rack.

I originally built my Mark I with the 2.25 turn rack and power steering. Despite my best efforts at the time I also had some bumpsteer that I couldn’t get dialed out. Between the fast rack and bumpsteer it was just plain scary at much over 75 mph.

I also considered doing the SAI mod but it sounded like it didn't work well with 15" wheels. I was able to fix the twitchyness by installing a slower rack (3 turns lock to lock) and adding Factory Five’s rack extenders. I adjusted the bump steer out using the method DV /DT showed in this post Bump Steer - The Solution
To minimize the bump steer I had to replace the offset rack bushings I originally installed with standard bushings and place the FFR bump steer kit rod ends under the steering arms with 3/16” spacers.
It’s like a new car now, no bump steer and the steering is very stable but still plenty quick. I really can’t believe how much nicer it is to drive now. It was a hassle to change it but it seems like it would be much easier than the SAI mod.

[h82crash]

Originally Posted by Cobra Cory

I have a set of Forte's bump steer pieces on the car already. Just wondering if I needed it for the SAI. My car is really twitchy on the highway and was told that the SAI kit will improve the handling even on a MKII. Hope I'm right.

Are you sure the tie rod ends are on the correct side of the spindle arm? Will be very twitchy if not. I know this should be obvious but sometimes we miss things.