3-link in a 900rw car... can it handle hard 60 ft launches

[baggins]

Ok so I'm trying to build a multi function car that will be mainly street driven with good handling in mind but I plan on hitting the local grudge race events as well. Now my question is will a properly built 3 link handle, or be able to at least come close to responding like a typicle 4 link would? I plan on always running drag radials and with my turbo'd 408 lsx combo some stout 60 ft times are in the future. Any insight is appreciated- Thanks, Nick

Also car has a stalled 4l80e
315/35/18 hoosier dr's

[exwestracer]

Ok so I'm trying to build a multi function car that will be mainly street driven with good handling in mind but I plan on hitting the local grudge race events as well. Now my question is will a properly built 3 link handle, or be able to at least come close to responding like a typicle 4 link would? I plan on always running drag radials and with my turbo'd 408 lsx combo some stout 60 ft times are in the future. Any insight is appreciated- Thanks, Nick

Also car has a stalled 4l80e
315/35/18 hoosier dr's

That's asking a lot of it. While you can build the top link and brackets to withstand the "lift" force on launch, keep in mind that the axle is only anchored in one spot. The housing itself takes a lot more stress than it would with a typical 4 link setup. There are a lot of 3 link cars out there with as much or more power, but most aren't designed for hard standing launches. You might consider a "5 link" setup, with top brackets out at the ends as well as the center. You can set it up for drag racing in a few minutes.

[baggins]

OK so your saying have 2 upper links for drag and then for street times run one centered upper link, correct? That sounds doable, now my next question is will the 3 link handle something like a 40 MPH roll or would that be too much stress as well?

Maybe I should just stick to a traditional adjustable parallel 4 link with some good ends like the roto joints or spohns so there is less binding and a watts or pan hard bar for lateral location. This car is mostly gonna be street and very rarely any auto-x type stuff. Do you feel a well setup 4 link will still handle fairly well?

[exwestracer]

OK so your saying have 2 upper links for drag and then for street times run one centered upper link, correct? That sounds doable, now my next question is will the 3 link handle something like a 40 MPH roll or would that be too much stress as well?

Maybe I should just stick to a traditional adjustable parallel 4 link with some good ends like the roto joints or spohns so there is less binding and a watts or pan hard bar for lateral location. This car is mostly gonna be street and very rarely any auto-x type stuff. Do you feel a well setup 4 link will still handle fairly well?

A properly constructed 3 link should handle a "40 roll" without any problems. Even with the same HP / torque, you are not loading the suspension anywhere near as hard as a standing launch. The 3 link (in my opinion) is a much better design in terms of freedom of motion for handling / autoX, etc. The other issue is that a parallel (side view) 4 link isn't the best design for launch; but once you start optimizing the instant center for launch, the suspension wants to start binding in roll (handling). Welcome to our nightmare...

[baggins]

If I do the 5 link the lower arms could be the same, correct? Meaning no change between the 2 setups

[exwestracer]

If I do the 5 link the lower arms could be the same, correct? Meaning no change between the 2 setups

IMO, yes. You will hear various ideas on this, but I recommend keeping them level for most all applications.

[MrQuick]

A properly designed torque arm might be a better solution.

[exwestracer]

A properly designed torque arm might be a better solution.

Thanks, Quick. Why didn't I think of that??? LOL

[baggins]

Can you explain the pros over the 3 link please

[exwestracer]

Can you explain the pros over the 3 link please

https://www.pro-touring.com/showthread.php?85354-Rainy-Day-suspension-basics-what-IS-the-deal-with-torque-arms

[Norm Peterson]

Just for other 3-link data points, the 2013 GT500 Mustang is at 662 HP, still uses the 3-link, and the full Ford factory 5/60,000 powertrain warranty remains in place. Apparently Ford had trouble with the standard axles twisting in the housing, so they used a tighter fit and rosette welds for the '13 GT500.

Shelby aftermarket efforts involve a couple hundred more HP . . .


The load on a single upper link is only about the same as the load in either lower. Not twice as it might be easy to think. The "problem" therefore isn't the UCA itself or even its fasteners, but the strength and stiffness of the brackets and local structure (which includes the axle itself).


I think at 900, you'd need at least a 9" axle or perhaps the 10" that's available through Mark Savitske at scandc.com.


A torque arm arrangement will still be subject to the axle tube twisting.


Norm

[Antti66ht]

I´ve been divided over 3-link ant TA also, and this is where I´m going now. I have upper link with leafsprings to limit the movement, and it worked. The link is on the right side to compensate torque... For the next "season there will be lower links and coil overs. Im using S197 Mustang MM extreme series lowers. Upper linkage structure, as predicted needs some strenghtening on the attachment point in the body, but other ways it functioned well. Attached some phots of arrangement and cracks on the horizontal pipe welds, where the UCA connects.
6447064471

It will have some substantial extra support. The motor has 500 hp and was dragraced with 9" race slicks...

On the banjo side there was no problems after serious beating. The bars are 8mm normal steel.
By no means this is not superior design, but a example that IF you make it properly it can handle serious power. Attachment to body is more work and nees some serious dividing of the forces.

Antti