I've decided to cut my front springs for a slight drop. I'm looking for 1" drop total. I've searched and it varies but it seems 1/2 coil is common for a 1" drop. I have stock 1982 Camaro Z-28 springs which are for A/C and stuff so unsure of the part number but I know they are stiff. I just don't have any heavy stuff anymore and the front end is higher than the back. Any idea what the average drop?

 

spend the money and get new springs. you're gonna have all sorts of camber issues with cut stockers

 

For the love of god people stop with the BS, you won't have anymore camber problems with cut springs than you will with off the shelf lowering springs. The camber problems come as the result of lowering, doesn't matter what kind of springs you use to do it.


From my experience 1/2 coil is worth any where from 3/4" to 1 1/2" of drop depending on the spring rate. With your lower rate springs you'll be closer to 3/4"-1"

 

BMmonteSS - Thank you very much for the information. I'll do the 1/2 coil as this seems to be in the right range for me.

 

So you've never trimmed any springs to get the desired ride height? It's pretty common place. And no I'm not advocating heating them whatsoever, but cutting is a acceptable method.

 

1/2 coil on the fronts of my camaro lead to about 1.25" drop, i'd go in 1/4 coil increments honestly.

 

thats good info. i need to cut mine too. i've alot of wieght off the front and now the front end is jacked up. i'm just too lazy too get out here and do it.

 

no i have not. i was just speakin of what i thought i knew. i know a few wyotech grads and they all seem to have the opinion that cutting stock springs will give you camber issues.

 

Camber issues come as a result of lowering....doesn't matter what type of spring you use. Camber is function of the suspension geometry and lowering will give you more negative camber, which can be corrected with an alignment.

 

The only true way to lower your car without any issues is with spindles and what not. You will not come across any problems by cutting your springs, that will not appear from lets say a set of Eibachs (unless of course you cut too much and you are on the bump stops)

There is nothing unacceptable about cutting springs, just make sure you use an acceptable method of doing your deed.

 

Haynes manual for a third gen actually suggests to cut the springs before you try new ones, that was pretty neat i thought

 

One question regarding cutting springs. If you would get a set of V6 springs, and cut 1/2 coil off, what would the spring rate be compared to the RS springs (I'm pretty sure I have the F41 option, since I have 34/21 bars, not sure if the springs were different on the F41 option cars though lol)

 

thats what alignment shops is for.. you should always get your front end aligned after any suspension altering..

 

If you have a V8 and used V6 springs, then you cut them, you would bottom out everywhere you go. The spring rate is much softer. If you have a V6, then there shouldn't be any issues.

 

OK, thanks. I was wondering about the actual numbers though.

 

you guys normally torch the spring to cut or cut off wheel? I have seen both and heard a long time ago that the cut off wheel with some maching coolant is better to avoid the heat build up. bad part is the torching was in a magazine article from chp or super chevy or one of them from primedia.

 

I just use a 4.5" cut off disc on a grinder, the spring does not get hot at all if you go at a reasonable cutting speed. I would never use a torch on springs!!!

PS The V6 springs are super, super soft, do not bother messing with them, they are totally worthless unless you like a squishy ride.

 

skip the torch, I use grinding discs on an air grinder. I cut for about 30 seconds then go to the next spring, then go back and forth, they never get hot that way. Took about 15 minutes total to cut through them both going at a slow pace.

 

However you should use a torch after it's been cut, correct ? In order to be able to flatten the top of the spring ?

 

No. You would risk ruining the spring. If you have that rubber bushing that sits on the top of the spring you will be golden.

Besides, the top part where the spring sits should have a bump that helps sit the spring in place so again, this is nothing that should be worried about.

 

Thanks for pointing that out, because I've seen some instructions that say to heat them up, turn them upside down, and flatten the top *L*. OK, thanks.

 

how about if you installed lowering springs and the front end is still up alittle higher than the rear...springs have been in the car a year and havent settled any more...B+G sport springs from spohn. they told me to cut an inch off to drop the car 3/4''

 

If they are in the car right now, then take a measurement of how high one full coil length is in height with the spring compressed.The coil is aprox 42% on leverage point of the A-arm at spring centerpoint. What this means is for ever .42inch you cut, you will get 1 full inch of overall drop. Basically cut off ABOUT 1/2inch of compressed height coil to get close to 1 inch drop- BUT NOTE MY NEXT PARAGRAPH.


This is not an exact science formula, but very very close. The cut coil does become slightly stiffer so actually cutting .42 inch MAY only drop it .95 inch instead of a full 1.0 inch- you get my drift.

Cutting off a 1/2 of compressed hieght may be more like 3/4-7/8" free height- this is why you need to measure one full coil loop at compressed height. Then when you remove the coil and it has expanded, you will have an idea of how low each full coil taken off will make the car drop.


Now here's the kicker- Some springs may have a compressed free coil length of 1", others may have a free coil compressed length of 2"- depends on the spring diameter, the spring wire thickness, and the overall # of coils tthat make up the rate. A 5" diameter 10" tall 800lb spring may lower 1" with a half coil cut, and a 5.5" dia 14" tall 800lb spring may lower 1 1/2" on the SAME CAR- Depemds on the spring and the car- thats why my about suggested formula is the best way to calculate your perticular setup.

 

I just ordered a set of Lakewood 70-30 front strut's. I've been looking at quite a few spring set's but I kinda just wanna cut my stockers. I have the stock WS6 springs. How much would I wanna cut to drop about an inch? The car sat very high to begin with.

 

Oh boy…

These are EXACTLY the people that should NEVER be allowed near a car that anyone cares about. How the heck is cutting a spring shorter going to do anything different to suspension geometry then installing a shorter spring??? Yes, lowering car can mess with the camber, but it that happens whether you put some eibachs in or cut stockers.

Drop spindles… probably shouldn’t even waste my time since they’re not available for most cars, but they can cause geometry issues also. Usually the problem is that the bearing spindle gets moved up, which moves the rim closer to the lower ball joint causing fitment problems or worse, a situation where the suspension will bottom if you have a flat tire, which is downright dangerous.

Now cutting springs… when you cut springs you increase their spring rate (think of the spring as a long piece of steel rod wound into a coil, if a sorter piece of the same rod is harder to flex/bend then a longer piece). This is an important thing to note since the front and rear spring rates have to stay in a certine ratio. If the front spring rate goes up faster than the rear it will cause the car to understeer (the front feels like it’s sliding out and the car doesn’t turn as tight as you have the wheels turned), and if the back gets stiff too fast than the car will oversteer (the back end will kickout). Neither is optimum, but oversteer is VERY dangerous (understeer you let go of the throttle and everything settles down, oversteer, well once you get there, no matter what you do you make it worse and the car will try to spin around, something that can’t be controlled on the street).

How much? Well, if you play with the factory spring rates you’ll find that you basically want to cut about 2x as much off the front than the rear to keep things reasonably balanced. Unfortunately, with a set of high performance (iroc, WS6, Z28…) springs, leaving everything else the same, cutting 1 coil off the front springs will lower things roughly 2.5-3”, depending on the year of the car (the earlier cars sat higher and cutting had more of an effect, the end result in height is about the same), where cutting ½ a coil off the rear is barely enough to notice (probably ½”-1” on most cars). There is an easy solution to this that I recommend, the rear springs have thick stock isolators, and swapping the rear isolators into the front pockets gets it back up to a reasonable height, and then using the thin front isolators (I think that they’re too hard to keep lined up in the pockets so I just use a length of heater hose pushed over the last coil of the spring) in the rear lowers the rear down roughly another inch or so.

What you end up with is a car that is lowered about 2.5”, about the same or slightly more than with sportlines, but with the higher spring rates of the pro kit.

With softer, non performance package springs you’re looking at more like ½ a coil in the front, and the same or slightly less in the rear, and you can even things out by heating the coil a ½ turn up and bending it in like the stock coil, that will usually get you to a good ride height and balanced spring rates.

What to cut with? Torch is fine IF, you know what you’re doing. You should be able to sever the coil in less then 10 seconds if you do and you won’t get the rest of the spring hot enough to cause a problem. If you’re a monkey with a torch and can’t get through it in 2 minutes, then don’t do it. Otherwise, a cutting wheel in a 4.5” grinder should cut them in about 30seconds or less, a little 3” wheel in a die grinder is a good way to spend a few minutes doing this, and dremel or hack saw… you’re in for the long haul, I’m guessing you’ll manage to turn it into a ½ hour job that way. Just make sure that when you’re done you dress/grind the cut edge of the spring so it doesn’t damage the spring pocket.

 

i just cut a half a coil off of my ws6 springs a couple weeks ago those are some stiff springs i would say a half inch drop at the most

 

I cut mine about 3/4"

 

Mine is an '88 Formula with WS6. Best I can determine, I think the front springs in this thing are the same as the 1LE springs. Needs to come down about 2" all around.

A magazine article I just read said to cut in 1/4 increments, then drive a couple days to let them settle in. Then repeat the process as needed. Probably good advice.

From what you say, I could take the rear isolators out and replace them with hose on the top turn. Then cut about 1/2 coil from the front springs. This would give me about 1" drop both front and back? That would be a good starting point.

 

It’s a reasonable approach.

A couple of thoughts:
- GM springs are wound in increments of 1/3rds, in other words, they all have some number and 1/3 or some number and 2/3 windings, it really shouldn’t make that big a difference, but for the springs to seat like stockers I’d suggest cutting them in increments of 1/3’s
- To me spring rate is at least as important as ride height. Remember as you cut the springs their rate will go up, and the rate of the fronts will go up faster than the rear. A front wheel rate that’s proportionaltely too high is much safer than vice versa, so your approach would be safe, but a balanced setup is always faster, so I’d consider cutting the rear springs slightly, use rer springs from a stiffer suspension package or stiffer sway bars… (I will suggest that when I’ve ended up happy with 3rd gen suspensions, I’ve always encd up with rubber rear bar bushings and poly front, so reversing that or poly front and back might be just enough to balance things.

 

so your saying the drop spindles aren't a good idea I have some but haven't had a chance to install them yet. they are AJE 1.8" drop spindles. the later ones that have all the problems worked out. and also Caster/camber plates that are adjustable. The guy said he got them from Summit and was told they are BBK I couldn't find they anywhere and they look like the J&M from Hawks'. Does this sound like it will be OK? also also how much should I chop the rear springs to even it out? Thanks for the input too Crossfire you always have had great info.

 

I couldn’t tell you for sure without seeing them… there are some that have great geometry (some of the truck ones) and some that are awful (nova/early f-body…)

To be blunt, these cars do not need camber/caster plates like something like a mustang. From the factory, ours adjust further than most mustang aftermarket plates, and there is less then a ¼” adjustment in most cars between the end of the adjustment range and the physical limitations of he strut tower.

I must have missed something, what are you evening out?

FWIW, I’ve never cut more than half a coil off the rear springs on an f-body, they have only a few, small windings so spring rate goes up REALLY fast when you cut them. Starting with a set from a performance suspension package, with half a coil cut you’re already over 200lb/hr, and these cars don’t like spring rates anywhere near as stiff in the back as they do in the front. The rest of the height adjustment can be done by adjusting the thickness of the spring isolator.

 

to even out the rear with the 1.8" drop spindles. wouldn't I still need to chop some off even with the thinner front isolaters on the back? I will post up a pic of the drop spindles so you guys can check them out. I ended up gettting a good deal on this stuff that is why I got the camber plates otherwise I didn't think they were really necessary either.

 

Good info.
Kory

 

83CrossfireTA--
Thanks for your input. Thought I would report on my results so far, as I just FINALLY got to the springs.

To start out, I have to point out that my Formula had about the worst "4X4" stance that I had ever seen. The car's handling and stance were well balanced. But I'm talking a good 4 inches of gap between the rear tires and the fender skirt edges.

In order of execution:

1. Removed the rear spring pads and replaced with hose. This lowered the rear about 3/4 of an inch, as the pads were about 3/4" thick. The LCAs are a little down in the rear, indicating it can take a little more drop without the need for adapter plates.
2. Cut 2/3 coil from each of the front springs, using a cutting wheel. No heat. (BTW, these are tagged "BZW.")
3. Installed the front springs with the thicker rear pads. Like the rear, I got a slight drop in the front, but not near what was needed.
4. Took the front apart again, and put the original thin front pads back on the front springs. Just like you indicated, I got about 2 to 2-1/2 inches of drop. It's looking good up front now.

I've decided to be happy with the front now. I've been working without a compressor, leaving the ball joints connected and raising/lower the inner end of the control arms. When I installed the shortened front springs with the thin pads, it became extremely difficult to get the lower control arms installed. The shortened springs wanted to push the control arms toward the center of the car. It took a lot... I mean a LOT... of force to pull the control arms outward and get the bolts in.

Besides, the control arm pivot bolts are now almost perfectly level with the pivot points of the ball joints. Can't ask for better than that! I'm done with the front.

Of course, this work has included all new bushings in control arms, panhard, sway bars, torque arm end, and transmission mounts. Also new boots on the ball joints and tie rod ends. I chose to use 100% polyurethane throughout. It's not that hard to replace the rear bushings with rubber if I feel they're too stiff later.

I also boxed the LCA's. Then I cut the panhard rod and put an adjustment bolt in it, then boxed it. You don't generally think about there being any flex in the front lower control arms. But the experience of putting the new bushings into them exposed a lot of flex in them. A new pair of tubular front control arms may be in the car's future someday.

So now I turn my attention back to the rear springs. (I had forgotten to look for tags on these springs. I'll check this time.) I will cut 1/3 coil from them and see how it sits. I bet it will be what I want. I hope the rear will come down about the same as the front has. I want the car to sit level or slightly tail up. Mainly, since the front control arms are now perfectly level, I would like to have the LCA's also perfectly level.

It appears that in lowering my 'Bird, I'm working to get it down to "normal" stock level, where others go lower. But I'm not willing to give up the solid handling of the stock non-variable WS6 springs. So getting down to "normal" will be enough. I also hope that this will properly line up the rear axle pinion angle. Had a slight vibration at high speed before, apparently caused by the pinion angle pointing up from the high ride height.

If it looks like I want, the final test will be a twisty road near home, approached cautiously at first to see how it handles. Previous to this work, I can't say that I'm sure how it really handled. It seemed neutral tending to understeer, but the rear sway bar links were completely rusted out and broken off! So in reality it had no rear sway bar at all!

More to come....

 

If its understeering now adding a rear bar will push it neutral or to oversteer. Hopefully not that far, since understeer is slow but safe, oversteer is fast but dangerous. If you're going to make a mistake do it on the side of understeer.

WRT problems getting the springs back in in the front, jack the back of the car and you can generate more force jacking the control arm into the pocket, and i usually use a flat prybar to move the pivot points out and line up the pivot bolt holes...

 

Final report on mine, so others can see how much I cut for how much drop.

1/3 coil off the rears, removed the thick pad and replaced with hose. 2/3 coil off the fronts, using the original thin pads. It's still not sitting on the floor. But I have the front tires on and sitting on ramps. Rear axle is sitting on jack stands. I set the stands to hold the centers of the axles at the same level as the centers of the front spindles. Weight on the suspension is the same as if it were on the floor.

Bounced the springs both ends and measured. It appears that the car is lowered about 2 inches overall. The stance is about 1 inch higher in the back. That's perfect in my book. Of course, it will settle in some with driving.

To give our readers an idea of how bad mine had the "4X4 stance," even dropping it 2 inches, there is still a 3-inch gap between the rear tires and the fender edges! But the LCA's are now perfectly level, as are the front control arms. That's with original-size 245/50-16 tires.

I won't go lower. "BZW" springs front, "NNL" rear. Confirms my suspicions that WS6 spring rates were the same as 1LE spring rates, though WS6 is certainly not the same as the full 1LE package. Anyway, cutting more may make it too stiff. Aftermarket springs tend to be variable rate, and I won't go that route. I like to do hard cornering, and I like the predictability you get with single-rate springs. I'm happy with it now.
Actually, as I think about it, as time passed I noticed that it had more understeer than it originally had. I haven't driven her in over a year. I hit a deer with it. Only going about 40 mph, and the deer was scooped up the hood and over the top. It landed behind the 'Bird, got up, and ran away wiser. Dented the hood and ripped off the left headlamp.

So I've had it parked while I repaired the hood and found replacement headlight parts. Found four replacement headlamp sets, with motors. Four replacement tail lights. Good to have for the future, just in case. Also scored a replacement aero rear wing. Rare because it's fiberglass but has the original "dish" in the top, not flat. One thing led to another, and I got started on suspension, which led to rear end rebuild. Then exhaust and the new Rhoads lifters. So memory of how it drove before is getting fuzzy. But it'll be back on the road within a month. Then I turn to paint.

 

Final Final report.

Main point here: EVERY car is different. Cut with caution and care. Take your time. Mine did not come out the same as 83CrossfireTA's results! I had to keep the spring pads in their original locations. (Read on.) But I'm very happy and indebted to him for his input.

I ended up taking the springs out one more time, as I finally decided it was still a bit too "4x4." I applied a torch at the 2/3-coil point on the front springs, 1/3-coil point on the rear springs, and flattened the tops of the springs to fit the original spring pads. My thinking here was to get the true full result of how much I had cut. Seems to have worked. I reinstalled the springs with the original pads in their original locations.

Final result is about 2-1/2" lower all around. Slightly "tail up" stance. My son-in-law thinks it still has too much gap in the wheel wells, but I now have ONLY 4" GROUND CLEARANCE. That's low enough! I don't know how some guys can drive down the street with some of the "zero gap" stances that I see on here. They must avoid speed bumps and dips!

I cannot roll my jack under the front K-member, even with the jack's pad removed. Neither will it cleanly clear my 3" exhaust pipe to get to the right side sub-frame. I have built a set of "pre-ramps" to get the front end up on ramps or get a jack under it!

Small price to pay for the results I got.

Keep in mind that the spring work was done in combination with other suspension mods, rear control arm links were broken, and original bushings were shot:

• New Energy Suspensions PolyGraphite bushings all around, including the rear axle torque arm and transmission mount.
• Boxed the panhard and made it adjustable
• Boxed the Lower Control Arms

The results: All I can say is WOW!
Preliminary handling tests have been unbelievable. "Like on a rail" does not begin to describe the difference.
Ride is a little stiffer than original. More than I expected, but not as much as I feared. Actually, the ride says to you, "Let's do it! Throw me into a curve!" Highway cruising (99% of my driving) is not uncomfortable at all. Very confident feeling.

Plans are to add subframe connectors, strut tower braces, and a "wonder bar." I will fabricate all these myself. Might as well. I haven't been able to find strut tower braces for a TBI car anywhere.

I'll try to remember to take a picture and post it. It's in the garage in all its bad-paint glory and its nose off, getting ready for new paint in the spring. But I can at least show you all the final stance.

 

I've read a lot of comments stating that cutting springs make them harder to compress. That's only partially true. If you cut off on the softer side of a progressive spring. Then yes. It will be harder to compress per inch on that cut spring. If you cut a linear and most common aftermarket spring that's rated at (for example) 600lbs. Then that spring will compress 1 inch for every 600 pounds of weight added to it no matter how much you cut

 

The problem w/ that logic is the 600 lb/inch rating is a function of the # of coil turns. A linear spring only means it behaves linearly as you compress it. That doesn't mean it doesn't change rate if you cut it. Consider the extreme example of cutting what used to be a 600 lb/in linear spring down to only having 1 turn left. That obviously will not deflect 1" when you apply 600 lbs to it, it will deflect a whole lot less than that. There are spring equations you can google that will show how the # of turns of a coil spring factor into its rate. If you only cut 1/2 a turn or 1 turn off a spring that has say 10 or 12 turns, you haven't affected the rate much but you have affected it. It's not enough for it to be okay to take a 350 lb/in stock spring and cut 4 turns off and retort "it's ok because it got stiffer when I cut it!" which is what I think some people assume, but it did get slightly stiffer.

link:

http://www.ajdesigner.com/phpspringr...e_equation.php

the variable "n", # of active coils, does affect the spring rate constant k.

Other relevant info: I'm a mechanical engineer.

 

Wow, along with slapping my face. I have someones else to slap as well. I've only cut an afco spring for a panhard bar experiment. It makes sense now. Less coils means it takes more leverage. This sucks. Maybe he didnt care, didnt know, or didnt want to tell me. Whatever

 

I'll try to answer this without a face slap.

A coil spring is just a long straight rod that has been curled up into a coil. If you take that long rod and secure it at one end, then apply weight to the other end, it will bend so far.

Say the rod is 10 feet long, you hang one pound on the end of it, and the end of the rod bends down one foot. Now cut the spring to 9 feet long, and hang the one pound weight on it. It will now bend 9/10 of a foot. It's just leverage. The metal of the spring hasn't gotten any stiffer, but the laws of physics say it will bend only 90% as much as it did before. Essentially, you cut a foot off the spring, and increased it's rate from 1 lb/ft to 1.1 lb/ft.

Coil the rod up, and the principal is the same. The spring's metal won't actually be stiffer, but the same weight won't compress it quite as far as before.

As for the original question, I cut my WS6 springs 2/3 of a coil in front, and 1/3 of a coil in back. At the same time, I had to heat a point on the cut end of the coils and bend them down the equivalent amount so they would lay properly in their seats. To get them to fit their seats, that meant I bent down 2/3 of a coil front, 1/3 of a coil rear. They ended up with the same "geometry," minus the amount I had cut. As a result, I lowered the car about 2 inches front and back.

As far as stiffness, they're WS6 springs, which are already stiff. I really don't notice a difference in the ride. But the handling was vastly improved.

 

.

 

When I lowered mine, I took this into consideration, from a post I read from Dean somewhere else. Good information.

But be careful to read closely. As Dean states, this 42% ratio thing is for the FRONT. The same 42% ratio does NOT apply in the rear, where the springs are set directly over the axle. That's a 100% ratio. Partly for this reason, and partly because of different rates in the back, and front/rear weight balance, you "generally" want to cut half as much in the rear as you do in the front, if you want to lower the whole car the same amount.

"83 Crossfire TA" and I swapped a lot of info in this thread, which helped me immensely. I ended up cutting 2/3 coil front and 1/3 rear following his guide, but I KEPT my pocket spacers to get what I was after. I got about 2" drop front and back.
Dean knows his stuff, too, and his word should be heeded.
Again, search the forums and find the guys who have actually done it and know the theory behind it.

My general advice when it comes to springs and lowering:

• MOST IMPORTANT: Set solid goals for what you want FIRST. For instance, I wanted to get rid of big fender gap. But WAY MORE than looks, I wanted handling performance and a streetable car. I still have "too much" gap, but 4 inches of ground clearance is as low as I'm willing to go.
• Search these forums and digest everything you can find before you turn a single wrench.
• THINK about what else you may have to do, like lower control arm brackets, adjustable torque arm to get pinion angle correct, etc., etc., etc.
• DON'T EVEN think about spring mods without also replacing the (likely) worn out bushings, upgrading your control arms and panhard, etc. While you're under there, do the whole package and do it right.
• Try to separate facts from opinions. My "opinion" is that cutting stock springs is better than buying lowering springs. Why? Because of the "fact" that stock springs are constant rate, and most lowering springs are variable rate, which can throw some interesting handling tricks at you. (Again, search the forums).
• Don't get the idea you can cut your springs once based on what somebody else did, and they'll be right the first time. Just accept the fact that you'll probably take that suspension apart at least three times.
• Cut less than you think you need to. Better to cut twice to get what you're after, than cut once and have to buy new springs 'cuz you went too far.
• Remember, remember, remember that what some other guy did will not fit what YOU want. Every car-- and every owner's goal-- is different.

 

so with all that said and done, and with all this geometry talk , has anyone found to have any problems as far as drivetrain alignment or blown out driveshafts or whatnot with only cutting the front and back springs?? theres tooooo mhuch hearsay but havent really seen anyone say dont do it cuz it will break something off if you do. and i mean speaking of experience not assumption.

 

I haven't heard any horror stories. The keys to driveshaft issues are balance and geometry. The driveshaft must be straight and balanced, and the rear axle pinion shaft must be parallel to the engine crankshaft.

Simply put, if you modify your ride height in any way, front or rear, you need to check the rear axle pinion angle. If you lower the car, then the rear axle is rotated in a way that the pinion shaft points down more in front. You have raised the axle in the car. You may need to raise the torque arm front mount to match, or get an adjustable torque arm.

On a small-block Chevy, the crankshaft is parallel with the oil pan mounting rails. So here's my method:

1. Put the front tires on ramps.
2. Put the rear axle on jack stands.
3. Remove the driveshaft.
4. Place an angle level on the engine's oil pan rail. If the oil pan is straight, just put it on the oil pan's side edge lip. Record the angle.
5. Place the angle level on the front of the driveshaft yoke on the rear axle. It should be 90 degrees from the engine pan rail angle. For example, if the angle on the oil pan rail was 5 degrees, higher in front, the angle on the pinion should be 95 degrees, also higher in front.
6. Adjust the torque arm to correct the angle. You might be able to get some adjustment on the front mount by slotting the bolt holes. Or you may need to get an adjustable torque arm.

In most cases, if the pinion angle is between 0 and 3 degrees down in front from the engine crankshaft angle, then you're good. On cars without a torque arm, it's common to adjust them 3 degrees down so they'll be close to zero under hard acceleration. Me, with a torque arm, I shoot for zero.

 

If the car sees any freeway cruising miles at all- does not really matter what type of RWD driveshaft style drivetain car it is with the pinion that articulates in suspension travel- you ALWAYS want to set the rear pinion angle at 1* down to compensate for thrust at crusing speed.. It is at mild throttle cruising speed where the Ujoints at at most used under strain. This static angle will allow for dynamic upward thrust of the pinion to make othe car cruise at about 0* when under load.

Now a high HP drag race only car is different. The throttle is to the wood all the way downt he track and thus a massive uplift of the pinion- Only in a very high HP case (were talking like 1200hp high hp,with slicks... then you want aobut 3* of downward static compensation angle.

A street car with static 3* anfgle going down the freeway wil cruise at about downward 2.5-2* angle and will wipe out the u-joints with bad harmonics not canceling the front u-joint angle. Front and rear u-joint angles need to cancel.

 

SlickTrackGod-- Maybe you know better than I do....

Everything I've seen, and also what you just said, was in literature mostly about leaf spring setups, where the rear end can have significant "roll" under thrust.

But how much can the rear end actually "roll back" when it's held by a a four-link or a torque arm? The torque arms on our cars have a lot of leverage with their long length. Then if you have 1LE or WS6 springs, all poly bushings in the LCAs, torque arm end bracket, and transmission mounts-- Doesn't seem to me it can roll much, if at all.

That's why I said that I personally shoot for zero degrees on the pinion angle.

I value comments on this. I didn't have trouble at cruise. But before doing my suspension work I went for a top end run. I had a bad vibration from the driveshaft that started in just before 140 mph, and I shut her down. Since I'm running a custom-built and balanced driveshaft, I attributed it to bad pinion angle.

 

These cars and pinion angle are different then leaf spring cars. Leaf springs will flex, they're built to bend to support the weight of the car. The TA really shouldn't. especially with stiffer aftermarket TA setups.

And 2 degrees pinion angle will not wipe out a u-joint.

People post all sorts of voodoo about setting pinion angle on these cars, that "I set it to X* and I found all this traction..." Bullshit. You moved something else that changed the traction.

REALLY, what you want is for the pinion angle at the front and the rear of the shaft to match, as close as possible, that will minimize harmonics, In other words, if the back of the transmission is a degree down, you'll want the front of the axle a degree up under load. If you feel that your setup has a lot of flex in it (stock TA, rubber bushings...) then go ahead and give the rear axle an extra degree or so downward angle (so in my example it will end up at 0*). It's not about the angle the rear joint makes, it's how different that angle is from the front.

 

We are saying the same thing- heck even 5* angle will not kill a u-joint, but 2* out of harmonics will in a fair amount of time. A properly set canceling angle will make a u-joint last severall years of hard use, but one with 2* off on harmonics will probably at best last you 10,000 miles and develop a vibration.

U-joints need to be at least 1* or more at each angle for proper needle bearing rotation, but if one angle is at 4, the other had better not be 2* away from it in order to cancel harmonics

 

sheeeeiiiit. so basically theirs more to it than cutting coils and removing spacers and such.. geometry is the key to a long lasting drivetrain?

my car is a cruiser. its never gonna see anything passed 70. i just wanna kill my gap about an inch. im not looking to slam. so with that ima still need to get an adjustable torque arm and such?

dont get me wrong, i dont wanna do something to it to later create a bigger problem, so if thats the case, it is what it is. just didnt know it took thiiiiiiiis much to lower these cars.