anyone have a coilover setup-- need advice

[davegt27]

Looking for some input on coil over setups for the Opel GT

Has anyone converted there GT to Coilovers

I will be headed to TX next month (God willing) so while I am down there I figured I would have a go at getting the race GT's front end squared away (so to speak)

Plan to buy a tube bender also so if anyone has any suggestions on tube benders that would be great.

Thanks
Davegt27

[jtb]

Yup.
I used afco coil-overs, fabbed the top arm, used the stock opel lower arm, built upper mounting points using stock location. I also built a strut brace, there's a picture of it somewhere...

Opel spindles, mazda rotors.

Anyways, I can't tell you much about how it worked because I haven't tried it out yet!

HTH,

jtb

[jordan]

Wow that is really something! Would be amazing if someone could turn that into a kit...I'm sure they would sell like crazy, probably the only downside would be the liability issue.

[opelwasp]

More pics More info please. And who did the work? You?

[Killer Texas GT]

Originally Posted by davegt27 Looking for some input on coil over setups for the Opel GT Has anyone converted there GT to Coilovers I will be headed to TX next month (God willing) so while I am down there I figured I would have a go at getting the race GT's front end squared away (so to speak) Plan to buy a tube bender also so if anyone has any suggestions on tube benders that would be great. Thanks Davegt27

Dave you headed to SA or Gainesville? Send me an email rod_z_opel_werks"AT' leonardonline.net . As for a bender my cousin may have one to selll I can check with him.

[Itsa '70 GT]

Originally Posted by davegt27 Looking for some input on coil over setups for the Opel GT Has anyone converted there GT to Coilovers I will be headed to TX next month (God willing) so while I am down there I figured I would have a go at getting the race GT's front end squared away (so to speak) Plan to buy a tube bender also so if anyone has any suggestions on tube benders that would be great. Thanks Davegt27

Just what kind of "race" GT are you building? As far as coilovers go, I'm fabbing the front end of my race car right now and know that the stock upper a-arm is going to have limited, if any travel with coilovers. In my experience, the snubber mounts/section of the front crossmember are going to be seriously in the way also. The fab that jtb did looks like a way to go....(jtb did you use all components from Chris Alston on your frontend? Just wondering as I spied those really slick screw-in upper ball joints!) Personally, I'm finding myself converting over to Mustang II style a-arms and spindles for my drag car. I know this wasn't much info, but I hope it helps....

Best Regards,

Bill

[jtb]

Hi,

The front suspension was built by both myself and a mazda mechanic race-car guy (so in this case he was more the design guy and I was the grunt labour!) Adjustable camber is nice (though not that easily adjustable - have to take apart the upper A arm and spin the threaded rod ends)

Picture of the strut bar is in this thread:
http://www.opelgt.com/forums/engine-...107N+rad+place
Strut bar is recommended as the load of the car is now on the shock mounts - this has been discussed in other threads.

Bump stops for upper travel are rubber bumpers from the Opel rad mount. (see picture - shot from under the car looking up) These were kind of an afterthought. Geez, if I had known you wanted pictures I would have made the welds prettier! Lower travel is limited by the shock.

You can see the swaybay mounts in front on my application - this is because of the engine swap, not the coilovers.

Those bolt-in ball joints are actually for a Toyota application - I have the Moog part number somewhere... I'll look for it.


HTH,

jtb

[Opelkurt]

That's some beautiful work. One thing though.... I recall reading a thread here (but I can't seem to find it now ), that said the upper mounting point on the Opel GT for that coil over shock set-up is not nearly strong enough to safely and reliably support the entire weight of the car and take to punishment of driving forces. It went on to say that area of the chassis was not designed to withstand that kind of stress and pretty much couldn't be modified to do so either.

Maybe he was only speaking of trying to race such a set-up. I hope I've got it all wrong..

-Kurt

[GTJIM]

The upper mounting points in the GT are not designed to take vertical loadings as the front suspension is a modular unit which contains the loadings within a separate unit. The upper mounting point for the coil overs needs to be tied into the cross member - the front suspension pictured has the upper stabilizing extension removed from the original set up and will just 'move' about and crack the inner guard with loading forces it was never designed to absorb. Needs a box-section going up there connected to the cross member and just located fore and aft by the upper mounting point - like the original.
The cross member is now no longer stabilized by the upper mount - because there is no connection!
IMHO

[jtb]

Originally Posted by GTJIM The upper mounting points in the GT are not designed to take vertical loadings as the front suspension is a modular unit which contains the loadings within a separate unit. The upper mounting point for the coil overs needs to be tied into the cross member - the front suspension pictured has the upper stabilizing extension removed from the original set up and will just 'move' about and crack the inner guard with loading forces it was never designed to absorb. Needs a box-section going up there connected to the cross member and just located fore and aft by the upper mounting point - like the original. The cross member is now no longer stabilized by the upper mount - because there is no connection! IMHO

I agree with what you are saying, but I just need some clarification. Upper stabilizing extension removed - I don't know what this is (maybe the mazda guy cut this off?). Does this mean the crossmember originally extended further vertically and somehow tied into the upper shock mount?

The inner guard - this is the inner fender?

I'm assuming (hoping) that the strut bar going across the engine compartment will aid in the vertical loading at the upper shock mounting point. What I think you are saying is I need reinforcement fore and aft of this mounting point tied into the opel box section? Or does it need to be tied into the crossmember?

I trusted the mazda guy to figure all this out, but I'd rather be safe than sorry.

Thanks,

jtb

[Itsa '70 GT]

Originally Posted by jtb I agree with what you are saying, but I just need some clarification. Upper stabilizing extension removed - I don't know what this is (maybe the mazda guy cut this off?). Does this mean the crossmember originally extended further vertically and somehow tied into the upper shock mount?

Sorry to say, but in looking at your pictures, the upper support that was the original shock support/"upper stabilizing extension" is now gone. I don't know enough about your strut rod and it's stress absorbing quality, but that may have been the Mazda's guy's answer to the otherwise unstable Opel mount for coilover use. There is a thread in here that showed an Opel GT coilover setup that utilized a modified original crossmember tower setup. Keyword will be "Jim Meyer"...All the best...

Bill B.

[saxybiker]

As many of you know we have been working on an Opel conversion for about 4 1/2 years now, but have not said too much. We were hoping to be ready for Carlisle this year, but unfortunately we will be about a month short. But, after this much time and buckets of money, we are not willing to rush it.

We have put in a custom front suspension with coil overs, pictures of which I hope are attached below. The only other addition we plan is to have a Monte Carlo bar running across the engine from the top of each tower to redirect the stress through the original shock tower and away from the sheet metal.

We plan to have this car driving this summer and then bring her to Springfield to join the other Opels and streetrods.

Vickie & Allen

P.S. Yes, they are Wilwoods

[GTJIM]

Yes - have a look at Vickie's set-up and you will see that the top of the coil-over is mounted to an extension of the crossmember above the upper A-arm.
The original connection to the inner fender ('mud guard' here!) above there is made by use of two clamping brackets with a rubber insert that clamps around a circular extension above the top shock absorber mount. Thus the front suspension unit is just 'stabilised' by the upper connection and not solidly mounted to the inner fender.
With your set up that has had the structural element removed from above the upper A-arm pivot there is no 'loop' of steel to contain the suspension forces - the inner fender is directly loaded ... and it is not designed for this loading. A brace between the sides above here will have no effect on vertical load carrying - it may just improve sideways flex.
The whole suspension cross member has lost all fore and aft stability and now relies upon the four mounting bolts that connect it to the frame rails to absorb the severe fore and aft impacts. It needs to be triangulated with the upper mount that has been cut off!
'Mazda Guys' know diddly-squat about Opel suspensions!!

Originally Posted by jtb I agree with what you are saying, but I just need some clarification. Upper stabilizing extension removed - I don't know what this is (maybe the mazda guy cut this off?). Does this mean the crossmember originally extended further vertically and somehow tied into the upper shock mount? The inner guard - this is the inner fender? I'm assuming (hoping) that the strut bar going across the engine compartment will aid in the vertical loading at the upper shock mounting point. What I think you are saying is I need reinforcement fore and aft of this mounting point tied into the opel box section? Or does it need to be tied into the crossmember? I trusted the mazda guy to figure all this out, but I'd rather be safe than sorry. Thanks, jtb

[jeff denton]

Some reinforcement will be needed for sure but I think this will be a really nice setup. I'd like to do this to my car, but need it done to so many others first so that I can call it stock...
We were in initial stages of grafting a Chevette suspension under Parts Car's shell, had been given a free 'vette. Went to get it and found it was a perfectly cherry rig, 86,000 miles, not a scratch on it, interior clean, glass perfect, needed only a clutch! Hauled it away for free, put it in the shop and started measuring up the front end/suspension. A friend came over and took one look and begged me to put a clutch in and give it to his mom, who needed it. He bought the clutch, we installed it, he drove it away and his mother loves it...
End of Chevette/GT suspension experiment. So far.
I like what I'm seeing here. Stay with it and share all you can here, please.
This setup in my car could very easily be tied into the upper front rollcage hoop and be very strong.

[Killer Texas GT]

I will have to agree with GTJim Vickie's set up will work just fine the way they have designed it even with out the 'Monte Carlo' bar ( and should that Monte have some angled braces also back to the fire wall with a little added structure for attachment even better).
The inner fender has no vertical structural integrity what so ever. It does have the lateral movement designed into it to stabilize the the GT front suspension mount as Vickie is intending for their coil over suspension.
The set up jtb is using will rip the cross member out on the first pot hole it hits, and send the coil over through the hood, even with a 'Monte Carlo' brace installed.
IMHO, to make it work two things must happen; 1) tube frame support from the firewall structure to the going horizontal through the front fire wall and with a radius bend 90 degrees down to the frame rails located no further forward that the cross member which the battery tray is mounted to. One One each side and a cross support between the two preferably behind the front fire wall then a minimum of one pipe support from the horizontal rail to the frame rail just behind the front suspension crossmember mount. 2) the front suspension crossmember will need to be further braced off to the frame rail any where from a 30 degrees to 50(but no more)degrees to the highest point left of the original crossmember, both sides, fore and aft, and will need to be adjustable to some degree. The strut will have to be mounted to the horizontal rail.
(Roll Bar Cage for the front end).

From the installer of independent coil front suspensions on GTs. (FWIW)

[Killer Texas GT]

Originally Posted by saxybiker As many of you know we have been working on an Opel conversion for about 4 1/2 years now, but have not said too much. We were hoping to be ready for Carlisle this year, but unfortunately we will be about a month short. But, after this much time and buckets of money, we are not willing to rush it. We have put in a custom front suspension with coil overs, pictures of which I hope are attached below. The only other addition we plan is to have a Monte Carlo bar running across the engine from the top of each tower to redirect the stress through the original shock tower and away from the sheet metal. We plan to have this car driving this summer and then bring her to Springfield to join the other Opels and streetrods. Vickie & Allen P.S. Yes, they are Wilwoods

Job well done!!! You will be astonished in the way it will handle and ride, GT GO-CART is all I can say (from the experience of my GT with independent coil front suspension)

[jeff denton]

Allen, your coilover mounted to the shock tower, is that sufficient? Was just studying this area on my car, seems in my case the shock tower could easily be braced into the front hoop and be awful strong, kind of like Rodney's advice. But without it, I wonder. Is the tower that sturdy?
Dave, you have a front hoop kind of like mine, don't you?

[jordan]

wow vicki, Jared told me that you had a trick front suspension for your project gt...He wasn't kiddin!

[jtb]

Man, I am not a happy camper now! I hate fixing things that I have paid other people to do! Well, the mazda guy better know more about rotary engines than he does opel suspension, or I'll be really pissed! I didn't rebuild the rotary as I don't know much about these engines. If it was a regular piston engine, I would have done it myself.

The only thing I can say in his defense is that when he designed it, it was to be a track car only, I later decided to street it.


Thanks for the tips, I will be modifying it to fix it.

jtb

[davegt27]

Wow thanks all -- JTB thanks for the PICS

I see Vicky's setup takes care of bump steer

Jeff for some reason I was thinking you found an 86 corvette that needed a clutch, I about fell out of my chair ha ha


Found an old thread

http://www.opelgt.com/forums/perform...sion-mods.html

basically I will be doing what Rodney posted (need to read it a few more times)
so that's why I need a tube bender
the tubes will go forward from the cage and turn down to the frame rails

(That’s kind of what I wanted from the beginning)

Then a flat would be added to the top of the stock suspension cross-member, then a second flat on the engine bay side tied to the tube that comes forward.

The two flats would bolt through the body


thanks everyone
Davegt27

[oldopelguy]

One big concern here, even with Vickie and Allen's set up, is that in normal operation all the weight of the front of the car is located on the center of the crossmember, and then from there to both of the car's "frame" rails. The outer parts, the vertical towers that the upper arms and top of the shocks mount to, are only designed for alignment and shock dampening loads.

Those towers are only spot welded to the main cross beam.

You will be relying on a handfull of spot welds, loaded in sheer, to align, dampen, and support the entire weight of the front of the car.

At a bare, absolute minimum, you need to actually weld those towers to the cross beam and add a cross bar on top to keep them from flexing so they can't crack and fail as easily. This would maybe be OK for something that doesn't see a lot of corners or a lot of miles. If you plan on actually taking advantage of the suspension advantages the coilovers offer you should at least add a pair of plates to the sides of those towers, out of something much stronger like 3/16" or so plate, going from above the upper arm mounts, down each side, and then in 8" or so in on each side of the main beam. This would probably make the towers able to hold some weight.

Were it me, really wanting that type of front suspension, I would measure a Manta front suspension, figure out the mounting dimensions, then make a new crossmember for the GT using those dimensions for the arms out of box tubing. Then, you could add your coilovers, bolt on a Manta suspension, use FWD wheels, and still be just about the right width for a GT. That's what I'm doing for my Kadett anyway.

[Itsa '70 GT]

http://www.opelgt.com/forums/attachm...g?d=1065194857

This is the link to what I was refering to in Jim Meyer's Opel GT parts/style IFS...Please note that he does not manufacture these anymore; you'll be on your own! Vickie and Allen's setup is really close to this style, but I do emphatically echo the need to finish weld, ( and box in if possible), the shock towers to the crossmember itself to strengthen the thing...Nothing will ruin your day, (running at 150 mph), faster than your frontend coming apart!

Bill B.

[jeff denton]

Look at the pictures Travis put in the thread Dave linked us to, there you see the shock tower attached to the "front hoop". This will work, big time!
Somehow I thought you had a rollcage reinforced chassis already, Dave.
I wish I could think of the name brand of my friend's bender, it works really well, puts out perfect, smooth, un-crimped bends. It is truly the very first, most important tool needed to build a pro-looking race car. A "notcher" is needed, too.
I was planning the Chevette swap because it looked simple, and does not use coilovers. Coilovers are a no-no in roundy round racing...
Another one will turn up, they are littered about and of no value. There may be another long winter coming up... Once one is fitted to Parts GT it could be swapped into any GT.

[SUBMARINER]

Coilovers are a no-no in roundy round racing I think Howe might take offence to that statement. Last time I looked my XL chassis had coilovers.

[GTJIM]

The removal of the front cross spring also reduces the fore & aft location and load absorbing capacity of the Lower A-arm. Even with the leaf spring in place the location of the lower A-arm is marginal.
Need to have "Zugstrebe" bars added that attach to the outer end of the lower A-arms and forward to the chassis.
Here is a past discussion:
http://www.opelgt.com/forums/3a-fron...shocks-gt.html
The Top end of the front cross member - above the upper A-arm has to be tied in to the whole set-up to prevent the whole front suspension pivoting about the mounting points on the chasis rails and be considerably strengthened to absorb the completely different weight loading from the top of the coil overs. This is a MAJOR redesign of the suspension - the leaf spring does far more than just suspend the car!!