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HHP springs intall

5857 Views 61 Replies 8 Participants Last post by  HC5120
Installed the HHP springs today. I am not going tp list every step and the torque specs as those are easily found.
HHP said no realignment is necessary. I may do that in the future, but the difference in ride height is the difference of having 1, 2, 3 people in the car, or a full tank of gas versus almost empty, etc., so we'll wait and see. Car drives really good, though.

American Muscle has a good install video on it: video

And on the BMR site they have directions for installing their springs, but it's all the same. Go to this link and then click on "installation" down a little ways on the page. BMR installation instructions

There are a couple of ways to do the rear springs. In the AM video, they remove the inside A-Arm bolt and drop the A arm from there. If you do it this way, you have to drop the exhaust some to get one of the bolts out. That's pretty much how the BMR directions are, but they have you remove the caliper and also remove the bolt for the lower trailing arm.

In all it took about 3.5 hours with two of us (though my assistant helped about 70% of that time), and the total time just depends on how stubborn the suspension parts want to be coming apart and especially going back together. If doing it again, I am sure we could do the whole job in 2 hours if we were both completely focused on it, and after having done it once. Some of the rear suspension bolts were a bear to reinstall. That's typical with suspension stuff.

Here is the difference in ride height with the HHP springs for all four corners compared to the stock springs.

Front left: plus 13/16; Front right: 0
Rear left: minus 1/8; Rear right: minus 7/16

Here is a pic of the stock front springs compared with the HHP spring
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Rear springs side by side:
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Rear springs installed

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We used this Eastwood strut spring compressor. Worked awesome. I researched tool options quite a bit, and this seemed to be the best made. The directions say not to use an impact on it, but reading reviews online, etc., lots of people do. It worked flawlessly. Seemed very safe. $165.00 from Eastwood.
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All and all, it wasn't too bad of an install. The rear springs actually took longer because it was tough to get the bolts back in the arms and the lower shock.

The biggest worry with this install is probably compressing the springs for the front struts. I felt the Eastwood tool was very safe and solidly built and dependable.

The car drives good. I can't tell much of a difference, but I don't drive it that much just cruising around town. We will see what difference it makes at the track.

As I stated in the drag racing 101 thread I made, this isn't a necessity for 10 second cars or even high 9 second cars if they race on an excellent track with excellent prep. But it's one more thing to (hopefully) add consistency for bracket racing for me, and help me on my home track which is challenging (we'll see). I have run a 1.53 and 1.54, but my 1/8 mile 6.80 at 4400 DA in my sig was a 1.58. I think I can do quite a bit better, but we'll see in a couple of weeks. My goal is to hit high 6.60s in the fall when the good air comes back and I have fresh tires. That would be solid for a 2.85 pulley and 93 fuel at 4500 DA. I would like to go back to a 305-17 tire, too, so this might get me closer to being able to do that.

If I have something messed up that you see in the pics, thanks in advance for the heads up.
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Strut is what determines how far suspension can drop before tire leaves the ground

Rebound dampening is what determines the rate it drops at

All you changed is the spring
We spend an hour on two bolts on the rear suspension. Sometimes that happens, and it's tough to get things lined up.
Yes, the lower shock bolts do not have to come out so ya coulda saved time there. The inner control arm bolts are fun ha. Getting those back in it’s all about jack position and good set of tapered bars. If you take the outer bolts out for the control arm and change the ride ht they are a ***** to get back in
You are correct: all I changed was the springs. Your razor sharp analysis is, as always, much appreciated, SickToo.

It will be fairly straightforward in seeing what difference it makes since this is the only thing I've changed, and I know that the car most of the time will run a 1.58 60' and now and then a 1.54. I have logged 100 passes or more, so I know what the car runs, and I know how (in)consistent it is. Pretty easy to test this.

I paid like $150.00 for the springs and did all of the install myself, so it's worth giving it a shot.
Would love to see someone have a baseline like you have, install the rears and log the difference, and THEN install the fronts and do the same
Would love to see someone have a baseline like you have, install the rears and log the difference, and THEN install the fronts and do the same
17 or 18 inch Mickey will do wonders to how it rides : )
More coils/smaller wire

Can see in the pic that they are softer than stock
In reference to the rear It should make it so that once the weight of the car is on the spring and it’s at its static height it will take less weight to compress it X amount compared to a spring with fewer coils

Ever cut one coil off a stock spring?

There is more to consider tho. I don’t know how close to 50/50 your shock is valved. My shocks are not adjustable
Yeah but remember what goes up must come down. Goal is to put weight on the rear and keep it there. Bias ply is a totally different deal

Hellcat already comes pretty low in the back. If you want it to transfer weight at the track I would call Mercer motorsports and concentrate on the front (increase travel decrease rebound dampening) cha ching

The stance of the car at launch is important too. Car has most of its weight up front and drag radial requires dead hook. Lowering the back/raising the front will help at the hit. The first foot is so important with these tires
I know someone that swears a diff brace cost him 7 thou in the 60

Backs up what you are suggesting ^^^ sorta
It could be worse…


rofl 🤣🤣🤣
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Not ready to frame and tub it yet huh lol

Did you friend video it from the side?
Mine works better closer to 20 than it does to 15

How wide is the wheel?

My wheel is a lil wider than yers. If? our tires have the same width tread mine would have a lil more volume. Your car has almost 50% more torque than mine does tho, and we aren’t at the same track…Who knows

It’s only money frame it tub it. Good wheels are 5k ea these days. Crazy
I forgot you have 3576 was thinking 3572 so what I said about the volume is was backwards. You have way more volume than I do. I woulda try different pressures while leaving everything else constant.

You used to 60 high 1.5

You really think the springs are better???

Looks like it slowed down : (
Listen to @Unholy707

He has a bunch of 1.4 60’ time slips and tons of logged data from the track


And his 60’ are the same as mine lol
Oh wow. You just hurt unholy’s feelings hard. Too big a tire lol.

Ha. I read what ya wrote. Throw a converter in it and see what happens. 3600. Maybe 3800. Or get a tune or a pc?

How much cash will you send me w yer 2.62’s if I send you my 3.09’s?

Getting 370’s for na bracket racing

I think 309 will be too low for turbo app even w 29” tire

Not dying to get rid of them. Willing to help out tho. You wanna try em?
If you race on a well-prepped track, then the stock springs are probably good, imho. Overall, I am happy with the HHP springs. The car rides just the same as it did before, and it's more consistent at the track, though testing has been tough due to minimal prep.
Congrats on going rounds. Hell yeah : )

I think it’s bigger than a supply problem. Something up with the formula. The glue ain’t what it used to be
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Yeah. Gonna see what it does Thursday
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