Mk4 Jetta suspension refresh

[ArrantWorm]

So, I'm finally ready to stop being cheap and spend some money on my good Pal Jerry. I have a few shocks that are shot, so I want to stiffen up this sponge cake of a stock suspension. I'm going to check my bushings tomorrow, but they're gonna get done anyway.

About 2 years ago I had a stock 2003 GTI 1.8T that I flipped, the suspension on that car is about what I'm wanting to go for but a bit stiffer, "stock+" if you will. My issue is that I have no idea on the frame of reference for spring rate, dampening or sway bar stiffness/thickness values, what numbers are stiff what's soft etc.

I'm perfectly fine with the turn in and general handling of the chassis "it's a boat, but its my boat" XD. I want to stiffen it up while keeping a ride my Mom wouldn't hate, lessen body roll and make the rear end more "happy" under trail braking.

I want to Make a fun car more fun and be able to lean into the tires more without ridiculously uneven tire wear from camber shift. Ultimately It's a wonderful economy car with "meh" suspension types and geometry, It's worth putting money in it, But I would get a second car if I was wanting to finally build a track/Hot lap car.

I aim to tune it to 130-180HP as I can afford to feed the bea$t. A limited slip is a strong desire at any horse power, since even stock the car can slip on launch. Big power is tempting, but fuel economy and the quick spool of the Vnt15 is more important to me. The thought of a low down 300ftlbs and more HP than the gti is pretty exciting though, but that's for another thread.

The "what is handling" thread was amazing, it puts it into very concise words.

 

[braddies]

Check out the Audi TT subrame swap, basically pull the frame from a junker mk1 Audi TT, fwd or awd any motor, convertibles have an extra brace welded on but our cars would need a bracket welded up to use it.

Subframe bushings are solid and usually fine to use, might as well press new bushings into control arms, quality wheel bearings, struts of choice (bilstein b6 with TT springs are tight but still smooth bumps nicely) poly TT sway bar bushings and new TT endlinks, poly top hat boots while your at it.

 

[ArrantWorm]

Thanks for the setup, so pretty much just rob an Audi TT ;P. I've had this car for 8 years now and I've seen the Audi TT subframe pop up a lot in discussions while I've been lurking.

Is the benefit from the sub frame swap the rigidity and / or that the Audi arms have better geometry?

 

[ArrantWorm]

Also, I've made figuring out suspension numbers my current study project. E.G. what is my stock spring rate and how to read the units to shop for parts. I tuned my RC cars a lot growing up, but I doubt that info translates directly other than springs. I used different weight silicone oils for my shocks and diffs there.

I've done some searching and found a good start on sway bar thicknesses, 23/18mm for a stock jetta.

Are there hard numbers to shop for shocks with or is it just stiff, soft and adjustable

I'm searching this afternoon, but if there is a write up somewhere please help me cheat and tell me XD

 

[braddies]

Is the benefit from the sub frame swap the rigidity and / or that the Audi arms have better geometry?

Yes, maybe identical subframes but with solid bushings installed from factory that are stiffer than the bushings the Jetta/golf got in their subframes. and better sway bar leverage with the strut-mounted design, which is why it only needs a 19mm sway bar (on most models?), and solid bushing already installed in a subframe ready to swap in vs pressing the old ones out of the Jetta.

Pretty sure there are painted dots on vw/Audi springs indicating exactly what the spring rate is, Shine racing customizes springs to whatever you like, think that our cars stock have 170lb(ish) springs

 

[Andyinchville1]

HI,

Check out some of the stuff from this site .... I would love to hear some first hand experience if you try it .... I am soooo close to pulling the trigger BUT I really want a 6 speed also!

Tubular Racing Subframe (MK4 all) : USRT | Real cars, Real Roads, Real Fast!

USRT Tubular Racing Subframe (MK4 all) - Our newest Tubular Racing Subframe substantially increases grip! It reduces front-end roll and keeps the tires planted flatter to the road

usrallyteam.com

So many choices so few $$ ha

Andrew

 

[ArrantWorm]

BUT I really want a 6 speed also!

the 02m swap has always tempted me, but I would rather get a "cheap" miata base for that cost. driving a "stock+" tuned S2k a year or so ago has me down bad for a K swaped miata.

I do think that on a wagon like yours however that the 6 speed would be pretty sweet. I doubt wagons weigh much if any more, but more ratios are always welcome. Just gotta make sure 6th is where you want it with the new final drive for fuel economy

Hell if I had a wagon I'd probably want to tune the engine to the moon. Just for the meme factor of a wagon UFO accelerating for a moment, then again after the shift XD