Rx7 Tri-link

[Boswoj]

Has anybody installed the Tri-link system in their Rx7? How much fab work is required to get it in? Does it make a BIG difference in the way the car handles? Give me some info if you can -

Thanks - Rick

[Hotshoe]

I do not have one on my car. I have driven several cars that have one. My opinion is that I do not see where spending the extra $$$ makes any difference.

[This message has been edited by Hotshoe (edited March 18, 2003).]

[rlekun]

Bos,

I thought you were getting out of racing for awhile? I hope you changed your mind.

I installed the Tri Link and the GT Panhard rod last year at the beginning of the season.
First, regarding "how much fab work does it require to get in? There are two points of attachement to the car. The front mount requires little or no "fab or fitting" to mount under the driveshaft tunnel. Just follow Jim's instructions implicitly, and make sure you get it parallel to the shaft and positioned (side to side) correctly (to avoid the trilink itself contacting the drive shaft.
The rear mount is on the top of the axle housing. A bracket is created by welding just a piece of straight metal stood on its side and welded to the housing. This is completed for each side of where the rear Trilink rod-end will go. Here is where I departed from Jim's instructions and reinforced the attachment to the housing with a couple of welded on brackets. If you check other previous threads on this topic from last spring you'll see others experience is that tri-link rod itself may be the weak point, not the mounting points. I bought extra rod ends and plan to buy and extra Trilink rod as a back-up (although if it did break it should be easily weldable at the track (if removed from the car).
One important note: I installed all this while also putting in a new fuel cell, so the tank was already removed, giving me much better access to do the rear welds.
The GT Panhard installation didn't really require any fabrication...just thorough preparation of the unibody frame "rails" and the driver's side axle where the shock and lower arm mounts.

Did it make a big difference for me? As you read my response, keep in mind that I can't separate what result is coming from the Tri-Link, what result is coming from the Panhard, and what result is coming from the combination of the two. I only had two race weekends on the new set-up and no test and tune time, so I don't think I have it dialed in yet. I think its too soon to say whether there are lap time improvements. My first reaction was that it turned the usually oversteering RX-7 into having a pronounced understeer. So I figure I should be able to work it back closer to neutral or slight oversteer. I also believe its more stable under braking. I think this set-up gives me infinite more options to adjust handling of the car. And in the interest of full disclosure, I have not been a front runner in ITA. I'm kinda high mid-pack...due more to driver inconsistencies than the car. I'm usually a couple of seconds slower at M-O than the top running ITa/7's of Tony Duncan, the Albrights, Dave Damouth, Rich G, etc.

Hope that helps. If you haven't already, buy Susko's book. Read it and then make up your mind.

[lateapex911]

I would reiterate the above comments, and add a few. Knowledge is power, and Jim's book is pretty cheap as these things go. If nothing else, give him a call and he'll give you the big picture.

That said, the entire premise of the tri-link isn't limited to the component itself. There is no doubt that when we lower the 1st gen car to the point we want it at for racing, the suspension goes out of it's designed range, with bad results. The tri link is part of a much larger system , and the resulting changes in roll centers, etc., change the overall balance of the car.

In the end, the system is very impressive from an engineering standpoint, and results in a car with a lot of adjustment latitude. Which is a strength for some, but a problem for others!

------------------
Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]

[RX767]

Originally posted by Boswoj:"Has anybody installed the Tri-link system in their Rx7? How much fab work is required to get it in? Does it make a BIG difference in the way the car handles? Give me some info if you can -"

Rick,
I installed rear part of this suspension last Summer. It takes longer than you initially think it will. The first piece of the Tri-link fits in the driveshaft well and it hard to screw-up. It is necessary to have another person in the car holding a box wrench when you tighten the bolts.
Although Jim Susko states in his directions that you only have to lower the differential to weld to the top of it, I think it would be worth the time to remove it all together. I switched to a 4:88 with larger axles, and I already had the new differential out. Additionally, If you are also installing the GT-panhard, there is a piece that needs welded to the driver's side of the differential. With it out, the welding was easier.
Before welding make sure you remove the plastic part of the vent. It will melt. I was too preoccupied with the positioning of the metal pieces that I forgot.

When burning the bushings out of the upper link, I drilled holes in the rubber and that allowed it to remain on fire to burn out. My neighbors "enjoyed" this part of the installation.

As other have stated, buy Jim's manual. It will help you understand how these components work as a system to overcome problems that occur when the RX7 is lowered for racing purposes.

I have not had this new suspension on track yet. I hope it improves my handling from the generally tail happy disposition.


rlekun, Jake and/or anyone else,

Did you also install the front part of G-Force's set-up, turn-in spacers and the front trailing arm bushings? Can any one give insights into that process in terms of time, problems, etc.? I still have that left to do this Spring among many other things.

Bill Emery
Glen Region
ITA#23

[Boswoj]

Thanks for the info guys - that is what makes this board such a great place!

I was told by another racer at the track that he loved the Tri-link setup so much that he thought it got him 1 or 2 seconds a lap! (wink,wink) The advice to go ahead and buy the set-up manual is a no brainer, and I have meant to do it several times but somehow never get around to it.

Oh, and thanks for the concern rlekun but that wasn't me that was taking a break - I was the one who spotted Balz's whole operation for sale on Ebay and posted a message hoping he wasn't going to take a sabbatical from our little community.

Thanks - Boswoj

[lateapex911]

Bill-

Tough to say, as I did it while doing other things- you know, the "while I'm here" stuff!

But I don't remember anything too awful. The front bushings on the link (Trailing) rod were pretty much bolt on, but on an old car, that can be a bear! The turn in spacers have one caveat: Check them frequently for tightness. I was having issues this summer and found I had loose components resulting in lots of toe change many times a lap! (It was one of those finds that makes you say, "Thank God! I don't totaly suck as a driver after all!")

I've used locktight and all, but I still tweak 'em once and awhile.

------------------
Jake Gulick
CarriageHouse Motorsports
ITA 57 RX-7
New England Region
[email protected]

[rlekun]

Bos/Rick, Glad you'll still be on the track. Sorry for confusing Balz with Boz...the mind is the first thing to go....

Bill, No, I haven't installed any other of Susko's components. I beleive RichG and DDamouth might have and they used to frequent this forum, but I haven't heard from them for a while here. I know richG had the same understeer problem I had after first installing the Tri-Link. He told me he put the turn-in spacers in and the problem was solved.
Since you brought it up, I just called and ordered the new Turn-in spacers from Jim.

Susko races at M-O alot so I've raced against (or more accurately behind) his car and talked to him a few times. He has a strong engineering background and really knows his stuff.

[RX767]

Jake and Rlekun,
Thanks for the insights and advice especially regarding the tightness of struts.

Jake,
I stuck my head under the car last night after putting dinner on the grill and these trailing arm nuts do not look like they have ever been touched. I guess I start soaking them with "PB Blaster" with the hope they move with ease later. I hate wasting an entire day on a couple of seized nuts or bolts.

Rlekun,
Out of curiosity, what size turn-in spacers did you order? I had a conversation with Jim Susko where he encouraged me to add the turn in spacers since they were essential to the overall system.


I was paging through the latest GRM and it was mentioned that Jim and G Force are going to sponser the CEN.IT7 class this year. Will he be giving suspension components as part of an awards package? I would enjoy that.

Bill Emery
Glen Region
ITA#23

[rlekun]

Bill,

Since I use the Panasports, I ordered the 1 1/8" spacers (which was Jim's recommendation).

Larry

My answer to the turn in spacer problem with them coming loose is to tack weld all three pieces in three places and drill the boltheads and safety wire them. I saw a guy have those two bolts come out on a pro7 car last year with scary results, he walked away but it really messed up his car. I added 1 and 1/8th inches of turn in spacer over this winter and will be testing next friday at buttonwillow raceway in prep for laguna seca in two weeks. just to point out how much of a geometry change they make it changed my toe out 1/2".

------------------
Daryl Brightwell
ITA RX7 #11
SFR, NORPAC
ITA RX7 #77
CSCC, SOPAC
E/P BOTH SOON

[rgrunenw]

Just getting caught up with this thread.

rlekun, my car has actually had the TriLink on it since Day 1. It was the best balanced race car I have owned - easy to drive, easy to push to the limits. However, after a couple seasons, I decided the limits weren't high enough which is when I went to Susko for additional advice.

My spring rates were low - 270 / 110 - and so I took the big jump to 450 / 300 per Susko's recommendations. It was then that the car developed push - although it was just as fast as it had ever been. Problem was that after a few laps the fronts would overheat and then the rest of the race was no fun.

I had the regular Mazda Motorsports spacers, but I went to the Susko's 1-1/8" turn in spacers, and the push went away and the balance returned. Unfortunately, the tires were toast by that time (corded all four during the last race), and I haven't raced since then. Hope to get out in May (Grattan, most likely) to judge the improvement.

Rich

[rlekun]

Bos, I'm in the process of installing Susko's turn-in spacers. I'm on my third 1/2" drill bit. Won't know how they well they work until July.

Darryl, good idea on the safety wire.

the ones i get are laser cut w/holes

[Jim Susko]

Hi Rick,

I see your question generated a lot of comments, many of them favorable. I'd like to respond to a few where the experiences aren't as good.

The Tri-Link/Panhard setup will definitely make a difference. Of course, you would expect me to say that! But probably 30% of my customers take the time to call me back and tell me how satisfied they are. How many retailers have that happen? The usual improvement in times ranges from 2-5 seconds. Some of this in handling improvement, and the rest is the improvement in confidence as the car is more savable. This makes marginal drivers much more confident. If someone buys my product and does not experience that kind of an improvement or experiences a problem then shame on you for not calling me and demanding satisfaction!

The newest GT version of the Tri-link is the strongest yet. Those who have had failures may be running one of the older versions. When I am given the opportunity to trace the origins of these failures it is most often because of improper driveline alignment which causes bottoming and side loading of the link, something which it is not designed to take. I have been running the older version myself for over seven years with not a single problem! Many of these years were rental situations where the car saw three times the normal seasonal use.

I also run the Turn In Spacers and had only one loosening problem seven years ago when I first developed them. Once I got the installation torque right (60-70 ft-lb) and used red Loctite, that has been a non-issue, and I don't bother to even check them anymore. Also, despite my higlighted instructions to the contrary many customers still attempt to grind a flat on the top of the strut tabs and it inevitably means fretting and loosening. I advise machining these flats only. So those of you who have these problems can solve them easily by following these simple steps.

The reasons I wrote the Setup Manual is because of the common view that you can just bolt on a part and it will solve all your problems with no other changes. A suspension is an involved system where all of the parts work together and small changes to one part can bring a cascade of geometry and handling changes that must be compensated for and optimized to get the most out of the system. For example most people know that when you bolt on a much larger carburetor to your engine with no other changes that engine power is often lost, not gained. Yet when the appropriate cam, jets, and exhaust are installed there is a net improvement. However this principle is often ignored when tuning suspensions.

Because the Tri-Link/Panhard system eliminates binding in the rear the car's oversteer is eliminated and understeer will actually result unless the car is resprung. When that is done the car becomes balanced again only it is much easier to recover. But even with the geometry perfect the nature of the McPherson Strut type front suspension means it will always have a tendency towards corner-entry oversteer even when it is neutral in steady state turns unless the shocks are chosen and set properly. For those of you who complained about this oversteer problem, the answer is shocks. And finally, just as you would never install only two legs of a three-legged table, installing the Tri-Link and Panhard without the Turn-In Spacer will always be less than the real deal to optimize all of the geometry problems inherent with the car.

For those of you who have purchased parts from me and are less than ecstatic with the results I want to emphasize I am still here at (419) 423-3884 to stand behind my products and assist you with any problems!

Jim Susko

[Speed Raycer]

Well Jim... welcome to the board. We've all heard a ton about you and we're glad to have you.

Your previous response has just sold another one of your Suspension books (as soon as I get around to calling).

Great to have you onboard!

------------------
Scott
It's not what you build...
it's how you build it
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E-mail me for deals on
Lightweight Replica Blocks!

[Boswoj]

Great discussion here, and thanks everyone for your input. Nice to get comments from the "horses mouth" as well - Thanks for stopping in Jim. I have heard from others that Pro-7 and ITA Rx-7 drivers often tend to really develop as drivers as a result of having to cope with the 7's inherent quirks. That may be the case, but I am still looking to make my car easier to drive at the limit, with better balanced handling, and higher limits. I STILL haven't managed to remember to call and order the book - but I intend to as soon as I can remember to do so during business hours!!!

Rick

[rgrunenw]

I may have posted this before, but I can attest to how Jim stands behind his products.

First of all, I have made numerous calls to him to discuss setup ideas. Jim is always ready to listen and share.

Second, my car has an early TriLink & Panhard setup. On Saturday of a double regional last summer, a mounting brace on the Panhard broke when another person hit me. Jim towed me and my car back to his shop from MidOhio, welded it up, and back to MidOhio so I could race on Sunday.

Now, I am not going to commit Jim to similar heroic efforts going forward, but I will say he goes over and above on standing behind his products.

Finally, he supports the IT7 class in Cendiv through his company, gForce Engineering.

Rich

(Hope to see you all maybe at the Cinci regional or Brat Bash!)