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TR6 Lowering TR6 front end

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R

richards

Jedi Hopeful
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I read somewhere that you could lower the front end of a TR6 by turning the lower front A-arm upside down.
How much lower would it make the car? Has anyone done it along with 1" lowered springs(GoodParts springs).
If you have done this, what was the final distance between the center of the front wheel to the wheel arch directly above the wheel center?
 
I don't recall the actual amount, but I can tell you it's fractions of an inch. Maybe worthwhile if you are already changing bushings and have the front end apart, but not worth taking it apart to do by itself - in my opinion.
 
I don't believe you would want to lower the car any further than with just the GP springs unless you plan to use the car for track only.
With the upgraded sway bar and GP springs, I have 2 1/2" ground clearance. I probably fiddle with my exhaust system 4-5 times a summer due to clearance issues.
 
Hi,

1" shorter springs alone will lower the car about 1.5" onto the tires and wheels (i.e., will close up the gap above the tire 1.5"). That alone might be too much, depending upon what tires/wheels are used may cause some rubbing or clearance issues during harder cornering. So check carefully.

TRF now offers an assortment of custom made aluminum spring spacers to adjust front spring height more exactly, that might help if there is a clearance problem.

Yes, the lower a-arms can pretty easily be inverted to go about 5/8" lower at the spring. This would probably result in close to 1" of drop at the top of the tire. However, I have not done it for two reasons:

1. Inverted a-arms will also move the upper bump stop 5/8" lower, which in turn will allow approx. 1" of additional upward travel at the tire. I'm concerned that would be too much travel and might lead to some serious tire rub or overextend the suspension. A possible solution would be to change the bump stop.

2. And, heavy duty springs which already lower the car (say 9" tall springs) don't have a great deal of seat pressure when the suspension is at full droop. So, using them in combination with inverted a-arms *might* leave the springs too loose and allow them to jump off their perches. I don't know this to be the case, I'm sure there will be some vartiation depending upon the exact spring being used, but it would be a possible problem to watch out for.

Richard Good can probably give you more advice.

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Yes, the lower a-arms can pretty easily be inverted to go about 5/8" lower at the spring. This would probably result in close to 1" of drop at the top of the tire. However, I have not done it for two reasons:

1. Inverted a-arms will also move the upper bump stop 5/8" lower,...



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Alan,

Just about everything I've read that you have posted I generally agree with, but, after looking over the front suspension on my TR3, I think I would have to disagree with you on some of these points.

Because of the way the lower A-Arms are made, they swoop DOWN right at the end where the trunnion/spindle attach. If you flip them over, what it effectively does is move the trunnion/spindle UP, therby raising the tire and wheel. The relationship of the rest of the parts in the suspension remains the same. The upper bump stop still remains on top of the lower A-Arm, and the lower rebound stop will still stop the suspension from lowereing any more then it did before the A-Arms were turned upside down.

If I'm wrong about this, please explain it to me.
 
Hi Art,

Easy to see why it would be confusing...

First of all, TR3 (actually, TR2 thru very early TR4) have different lower a-arms (and upper) due to the 0-degree caster geometry. Now, I don't have a TR3 to go take a look at, but I'm pretty sure they still have the "dogleg" shape that allows lowering the car a bit just by inverting those arms.

It's actually a little easier on the earlier cars, because the parts aren't right- and left-handed. On 3-degree caster cars beginning with TR4, the arms need to be swapped side to side, as well, when they are inverted.

When the lower a-arms are inverted, the outer joint at the trunnion actually stays the same height. What changes is the lower spring perch is dropped about 5/8" and that's what allows the entire car to settle slightly lower. The offset is about 5/16", so inverting gives a total of about 5/8" and the actual amount the body is lowered is probably 7/8" or so due to the non-parallel geometry of the front suspension arms.

Yes, the bump stop remains on the lower a-arm. But unless the size of the rubber bumper is changed, once the a-arm has been inverted that stop will be lower and will allow another 5/8" of travel before it halts the suspension's movement. This means movement of the wheel and tire up into the wheel well approx. 7/8" more than original. Depending on the tires and wheels on the car, there *might* be problems with tire rub, etc., particularly if there are also shorter "sport" springs being used and during hard cornering when the suspension is heavily compressed.

Hope this explains it okay. It does lower the car a bit, I can assure you. I've seen it done and it was (is?) a common TR racer trick.

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Just curious, does anyone make a dropped spindle for the TR6. You see them all the time on old American iron.
 
Alan, thanks for the input.
Any of you TR6 people out there with Good Part (short type)springs, could you measure your front and rear wheel centers vertically to the wheel well arch, so as to compare to my dimensions:
My car:
These are the vertical measurements from the wheel center to the lip of the wheel well arch.
Front: passenger side: 14.12 inch
Front: drivers side: 13.63 inch

Rear: passenger side: 14.25 inch
Rear: driver's side: 14.38 inch

The car is not square. We tried to get both the fronts to match each other, and we tried to get both the backs to match each other. So far this is the best results, playing with the rear springs and spacers. The car looks level. It is not lower in the rear. Looks level side to side and front to back. I would never want it to be lower in the back relative to the front. I do not mind the front a bit lower than the back ( in the old days that would be called a Daytona Rake).
So measure and let me know, both stock and non stock TR6s.
My car is a 1974. I will try to get a picture up this week- end of the car on a flat area to display it's additude.
 
FP 14 dead
FD 13 1/2"
RP 14 1/4"
RD 14 3/8"

There is something wrong with FD - it looks low. It has since it came back though, and it didn't before it went out.

Blimey - just re-looked at your #s mine are pretty close. I feel a lot better now!!!!
 
goodparts. no aluminum spacers.
new kyb on front
rebuilt uprated levers on rear.
nissan diff and toyota box. i doubt weight difference is an issue though
 
Alan is the Nissan the same dif as the Infinity swap?
 
It is, Infinity is 'upmarket' Nissan. The same diff is also known as the R200 diff I believe.
 
I was wondering if the Infinity box was a better unit?
 
If you really wanna spend some $ get the nismo one. Otherwise I *think* they're the same apart from the ratios.
 
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