5.7iroc-02ws6

Just got the install done tonight on the IROC.. really nice piece... couple q's..
-What angle is everybody running? Spohn recommends -1 thru -3 on street cars... (mine is running high 12's) (Oh-When you set this I assume the car has to be completely level?)
-Driver side rear bolt on the tranny xmember is stripped/rusted? Any suggestions or has anybody else enountered this?
-Car sounds different on braking and acceleration now (haven't hit it hard yet)... braking seems to growl now?? Any thoughts? similiar situations?

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I can't wait to get it all dialed in and try it out on the track.. I have MAJOR traction problem out of the hole...
Ryan

Twilightoptics

#1: Spohn is right with the degree setting. You want to stay away from anything in the + and zero. You don't have to have the car level, just the suspension loaded (IE Ramps in the front, and ramps in the back) I've gotten different pinion readings by jacking the rear end up by the housing, than with the tires loaded like on the ground. Even if the car is at an angle you can get a reading of say 12º front, set the back to 13º.

#2: My '85 had a stripped one, I left it. Most of the force the crossmember sees is from the trans pulling it upward on acceleration. Someone else might know the best way to cure the situation though.

#3: Friend of mine said there were alot of sounds that went into the passenger compartment with the spohn arm. It's a much more solid piece, so it's going to transfer some things. Make sure you have the shackle set right, greased, and tightened down.

brutalform

Depending on the material your bushings are made of, will help to decide on where to "experiement" with the settings. Solid, or ureathane bushings will most likely need less than stock rubber bushings, as rubber bushings will allow more suspension movement over the others.

Dale

iTrader: (12)

There are no bushings in the spohn tq arm.

As for the stripped bolt, I would fix it. The TQ arm will see a downward push every time you go to shift gears, and also hitting the brakes.

Yes, I have alot more sounds with it, but its solid and feels great. Only thing I really dislike is a "click" sound whenever the arm moves up or down.

5.7iroc-02ws6

I will check my front pivot point... wonder if I need some grease/loosen the pivot point up. I also think I need to fix that stripped bolt... might be causing a weird feeling...
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W/the rear axle loaded on jackstands and the front on the ground you can still set the pinon angle?

Shagwell

yes, because pinion angle is pinion degree minus driveshaft degree(maybe it's visa-versa...it's ben awhile) so, no matter the front/rear height, as long as the rear suspension is loaded proper, the angle is correct. - That said, I run 6 degrees(commonly thought of as too much). A manual trans car always want's more, and that's where I've found the best traction in my car, though probably not the best on u-joint life. - Every set-up is different.
- As for the noise, sounds to me like the front pivot bolt is a bit over-tight. They're locknuts, they don't have to be heman'ed, just snug. The looser they are the easier it is for the pivot to move proper.
- as for the trans x-member bolt, I ran my car for years on 3.... It's especially less worry some with a divorced tq arm.

86irocterror

ok guys i just finaly did my pinion angle on my spohn torque arm today. i set it at -1 degree. but i see someone said they get a different reading if the pumpkin is jacked or the wheels are suporting it. lol of course i went to the pumpkin for ease.lol. should i re check the angle with it suported by the wheels or jack stands under the axle housings instead of the pumpkin. i didnt think it would matter since everything is tight and bolted down. i didnt think the rear being suported like that would make the reading less accurate. but the car is going to get a 700 hp dart 400s/b so i need it to be right on in the end.

83 Crossfire TA

iTrader: (2)

So you mean that you have a 1* difference between whatever you measure the pinion angle to be and the driveshaft angle?

The fact is that in most cases pinion angle should be measured off of the transmission output shaft angle (probably easiest to measure off the yolk, and the pinion should typically be about a degree down from the transmission, the driveshaft angle connecting it makes no real difference as long as it’s within a reasonable range, probably 3* or so of it, much more then about 4 or so usually destroys u-joints.

Shagwell, if you really have 6* difference between your driveshaft and your pinion that is actually at the point of getting dangerous, unless you actually have enough slop in your rear suspension/tranny mount/engine mounts that it straightens out when you launch, and if you do then you should fix that rather then live with it.

Jacking by the pumpkin will in most cases cause the TA/TA mount to flex and will probably change the pinion angle a little.

Typically, real world, you’re actually shooting for something in the -1 to -2 range for most suspensions that control axle wrap up well, and -2 or -3 on something like a leaf spring suspension without traction bars that will wrap up a little more. On something like a TA suspension, it should be pretty tight, unless you’ve got significant flex somewhere I would be surprised if you got more then a couple of degrees rotation on a launch so I would be shooting for about a degree down static setting. Of course, this is relative to the transmission yolk.

I suspect that some of the driveshaft harmonics that people complain about in f-bodies is really a problem with drive angle phasing, which it seems like no one actually plays with/checks.

The reason that there should never be a 0* angle between adjacent parts in the drivetrain (parts on either side of the same u-joint, like between the pinion and DS) is that with no angle between them the bearings in the caps won’t move at all and will result in flat spots in them causing them to prematurely wear out.

ThirdGenLS1

yep shoot for anywhere in the -1 to -2 range.

Blackbari

I too, have just finished installing the Spohn adjustable torque arm. Yes, the same bolt that stripped on your car, happened on my '88 IROC. However, the bolt hole stripped. Looks like I'll have to drill and tap it for a larger size bolt.

The question I want to ask is about the glued on rubber sheets (isolators?) on the crossmember mounting plates to trans floor. Did yours come with that? I left mine on and installed it this way. How did you do yours? Anyone recently installed a Spohn torque arm?

Mongoose

iTrader: (2)

I've been running one of these for years. I have mine set at -1 degree as well. I stripped the same hole on the drivers side also. Went the heli-coil route to fix the problem. No problems since.
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92RSZ

iTrader: (6)

I got mine set at -2. So far it has been good for a 1.70 60 ft. at the strip with bfg drag radials.

5.7iroc-02ws6

I left the isolators on... What little insulation you can get from noise/vibrations will help..

Later