Rear F-body suspension...food for thought

[WMCCjames]

Well, after a trip to the dragstrip last week I realized I have some glaring issues I need to resolve with my suspension in order to get the car to hook up. Been doing lots of reading and searching....came across this website that has some interesting points to consider when it comes to the rear suspension on an F-body car. I have always wondered just how much those poly/tubular/boxed LCA's really compromise the movement of the rear axle. Food for thought.

http://hewsoninc.ca/mythinformation.htm

[MattODoom]

Good stuff.

[scholtmj]

Very interesting website, but everyone has their own personal opinion. Have you checked out Madman racings website? They get F-body's to hook like crazy. I have tubular LCAs with poly bushings and a non-adjustable TA. I don't think my suspension moves enough to cause significant bind in the LCAs although I have thought of doing a combo poly/rod end style LCA/PHR. My new front A-arms have rod ends and they're not harsh on the street despite what I've read about rod ends and street use.

But that's my own opinion

[GETGONE]

Spend some time in LS1tech's suspension forums and you'll find most of that stuff. That's why I went with the rod/poly PHB and am going that way with the adjustable LCA's. They allow for the twisting that's needed but aren't as harsh as rod/rod components(right DanO?).

[WMCCjames]

Yeah, after much debate I am going with the poly/rod LCA's myself....it's either that or IRS.

Matt....Madman's stuff scares me quite frankly.

[GETGONE]

Who makes IRS that fits, or are you going to custom fab one in over the winter?

[WMCCjames]

It was a joke Wade.

[GETGONE]

There are a couple guys that have custom made IRS setups in 4th gens.

[JoeliusZ28]

On my new LCAs I have poly bushings on the axle brackets and rubber bushings on the chasis mount. Reading that makes me wonder if i should flip them or get rubber bushings for the rear.

I disagree with that guy that they dont make a difference though. My axle doesnt initially "Buck" as bad as it used to when i dump the clutch or catch a gear. Instead of wheel hop it just puts rubber down.

[iroc85blu]

poly rod for the win, but take what that guy was saying with a grain of salt because there are people for and against just about everything out there with evidence to back it up. Basically sort through the crap and figure whats going to work best for u.

[DanO]

Spend some time in LS1tech's suspension forums and you'll find most of that stuff. That's why I went with the rod/poly PHB and am going that way with the adjustable LCA's. They allow for the twisting that's needed but aren't as harsh as rod/rod components(right DanO?).

Yup.. they definately give you a "connected to the road" feeling.. but for a weekend vehicle its fine.

Lets look at the issues more in depth...

OEM needs a component that is cheap to manufacture and must meet all NVH requirements and pass all durability tests. Thus, for the stock vehicle intentions its perfect and you wont find one better for less $

Polyurathane, personally dont like it on suspension, but works great for engine mounts. Many of the issues were listed. But what drives the need for polyurathane? its the higher 'spring rate' of the material and thus limits deflection as load is applied. It still has some compliance and again is cheap to produce in aftermarket. if the Polyurathane had a very low coefficient of static friction it would be a better choice.. i'd pick somthing like delrin over polyurathane... unfortunately the masses have been mislead by clever and relentless false marketing.. ("turbos use free energy".. need i say more..)

Rod ends.. by far the best design for suspension.. not so good for NVH or durability. The design will locate your suspension exactly (almost) where you want it to be and provide a very low coefficient of friction.. typically teflon friction surface. Great thing about teflon is that its static coefficient of friction is lower than its dynamic coefficient of friction.. to most that doesnt mean much.. but it does mean quite a bit!! Now the drawback is the extremely high spring constant and thus transmits impact loads very well and these impact loads are slightly annoying and damage the rod ends over a period of time. These are the ones i chose and still know that the suspension is going to be exactly where i want it.

Now the optimal solution would be a combination rod end and polyurathane or other material... but by the time you optimize the NVH and durability requirements.. you'd be almost back to where the stockers or 1LE components are.... and those are alot cheaper!!

This is why i see 2 choices... stock/1LE or Rod end.. there can be variations.. but money wise these two make the most sense for what they offer.

[GETGONE]

Damn know-it-all engineers!

[scholtmj]

Yeah, after much debate I am going with the poly/rod LCA's myself....it's either that or IRS.

Matt....Madman's stuff scares me quite frankly.

What scares you? Build quality? I've just read stuff in articles and they get cars to hook, at least the magazine cars do.

I prefer Spohn stuff myself.

[WMCC Gary]

Very Interesting read.

[lozanoa11]

Sticky to the link??