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  1. #1
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    08 i have no idea, the car moves to the left under load

    So I recently swapped over to my winter tires/rims from the drag setup. I live in NJ so it's just time to be ready for snow. Anyway, when on the drag radials, the car had a noticable sway when accelerating hard. I've driven cars on slicks before, and just attributed this to the bias ply wiggle that you get on that setup. It is what it is.

    The problem is now that I've swapped the setup out, I still have a very noticeable sway when accelerating. Specifically the car twists towards the passenger side. The movement is very subtle, and only under hard throttle, but it's alarming to me none the less. It's almost like it gets up on top of the tire and rolls to the side. Very hard feeling to describe accurately I checked all of the carrier bushings already, and all look fine. I know my shocks are beat, and I def need to do an alignment for the front soon, but I don't really think that is the issue here.

    For the record, the car is an 08 Rt Charger, with about 100k on the clock now. I have 300-400 passes on the car, street and track, with 1.6/1.7 60fts every time.
    The car was babied by the original owner, up to 60k miles, and then I've driven the hell out of the car ever since. Previously I broke both half shafts, and split the stock convertor, then broke the input shaft on the trans. All of which was fixed correctly.

    Anyone have any ideas where I should start looking under the car?
    I'll have it in the air in a few days to try and nail down the issue, but I thought if someone could give me a head start, that would save time.

    *Edit*
    This is not a tire traction problem. It happens identically each time I accellerate, same manner, same direction. It's not a violent move, nor does it vibrate, shake, bang, rattle, or any other noise. It's more than the normal driveline twist under torque load. I just haven't pinpointed the issue yet.

    08 Charger RT Resurrected
    Fastest Recorded Pass; 11.48 @ 120mph
    **Stock 5.7 block, Stock heads, Stock cam, Stock converter, True CAI routed under the bumper, JBA shorty headers, JBA catless mid-pipes to dumps, stock transmission, stock carrier, stock gears, a lot of nitrous, sticky tires, colder plugs, and a really good tune**



  2. #2
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    Would be cool if you have a vid from the track of the car launching. 11.48 is moving for that combo. 125-150 shot of gas?

    I hope it is something simple like dead rear shocks though I agree getting her on a lift to check everything makes sense. Take a good look at the rear cradle structure
    itself. Northeast car subject to road salt in addition to a ton of hard launches at the track. . .. . . .never know.
    15 Grand Cherokee SRT: Staying Stock!!!

    05 Magnum RT:
    5.7 Personal Best: Heads, Cam and Spray - 11.46 w 1.59 60'

    6.1 Personal Best: Forged, Novi 1500 and Spray - 10.405 1.566 60' @ 129.69
    7.4 Personal Best: Aluminum 449 - 10.736 ET , 1.589 60', 125.05 MPH NA
    7.0 Personal Best: Iron 426 - Whipple 2.9 - 10.5 @ 132 1.6x 60' . . just getting started

  3. #3
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    Quote Originally Posted by bklynmag View Post
    Would be cool if you have a vid from the track of the car launching. 11.48 is moving for that combo. 125-150 shot of gas?

    I hope it is something simple like dead rear shocks though I agree getting her on a lift to check everything makes sense. Take a good look at the rear cradle structure
    itself. Northeast car subject to road salt in addition to a ton of hard launches at the track. . .. . . .never know.
    You wouldn't believe me if I told you what size the shot was on the nitrous system haha. The car has made too much power for the driveline for some time now, but still I persist.
    I was hoping it was just rear shocks because I was finally going to break down and upgrade them from stock this winter, but I just don't think that's it, unless I broke a shock mount. But that or any other hard brake to a part would show up in different scenarios. Under normal driving conditions, it doesn't happen.

  4. #4
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    Well, I took a long look under the car tonight trying to find something wrong. I started in the back under the cradle......Nothing. Although there is some surface rust on some of the parts, nothing I can't sand off. All the bushings surprisingly look good, no play in any of the arms. Good on Dodge, because I beat this car haha.
    Anyway, after not finding anything in the rear, I moved to the front on a hunch. Again everything looks top notch, except the driver side motor mount is clearly torn. Passenger side is fine. Although this is definitely an issue I need to fix, is this what I'm feeling in the car?

  5. #5
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    The driver side mount keeps the engine from rising up when accelerating. Even though it is broken, there should be a safety catch. In the old days motor mounts didn't have the safety catch and it scared the heck out of me when my 283 V8 lifted up and the fan hit the metal fan shroud in my 59 Chevy Impala!

  6. #6
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    Quote Originally Posted by 2005rtmag View Post
    The driver side mount keeps the engine from rising up when accelerating. Even though it is broken, there should be a safety catch. In the old days motor mounts didn't have the safety catch and it scared the heck out of me when my 283 V8 lifted up and the fan hit the metal fan shroud in my 59 Chevy Impala!
    I agree, and it's probably why it's only doing it under heavy load and in no other scenario. Time for poly mounts or solids.

  7. #7
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    I had a blown driver side motor mount and I never experienced pull to one side like you're describing. When i changed my rear cradle back a year ago, i had an alarming amount of serious rust on the top of my cradle and was quite surprised that nothing was broken. Maybe there is a cracked weld that you cannot see unless a load was put on it? It sounds like the alignment shifts under load which would mean something is moving for sure....and not sure a crack would open that wide and then close up again.
    2006 Charger Brilliant Black R/T w/R&T Package, 6.1 Arrington based 426 Hemi @ 13:1 compression 2016 Hellcat Charger rear cradle and brakes swap, DSS 4" custom driveshaft, 3.09 Scat Pack rear diff.

  8. #8
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    Quote Originally Posted by ChuckWagon View Post
    I had a blown driver side motor mount and I never experienced pull to one side like you're describing. When i changed my rear cradle back a year ago, i had an alarming amount of serious rust on the top of my cradle and was quite surprised that nothing was broken. Maybe there is a cracked weld that you cannot see unless a load was put on it? It sounds like the alignment shifts under load which would mean something is moving for sure....and not sure a crack would open that wide and then close up again.
    I can get behind that premise. I just couldn't find anything else that justified the movement under the car. Everything is tight and solid, and like I mentioned alot less rust that I expected to find on all the pivot points. I was planning on dropping the diff in a few weeks anyway to do some sneaky gear stuff, I'll find out for sure at that point.

  9. #9
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    So the issue is most certainly not just the motor mounts. Although that hasn't been fixed yet, I can tell after playing with the car that the movement is 100% originating from the rear of the car. I went over everything again this morning. Although there are a few busings on one of the trailing arms with a crack in the rubber, none of the bushings are blown, and I couldn't find anything that looked off.
    Except, the passenger side front mount on the cradle looks farther away from the body of the car than the same mount on the driver side. I checked the bolt, it's as tight as I can get it with a 4ft breaker bar. The bolt only turned a quarter turn, and I don't consider that loose. Other than this I cannot find anything that looks bent or out of place, or cracked.
    The first time I looked over everything with the suspension unloaded, and the second time I did it with full weight on the suspension.
    I just don't know where to go from here.

  10. #10
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    Pictures?

  11. #11
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    Quote Originally Posted by Jay Z View Post
    Pictures?
    I will try to take pictures tonight. It's super hard to get my phone up there to take it. The passenger side front cradle mount hangs about a 1/4 inch or more from the body, while the passenger side front mount sits closer to an 1/8 from the body. The rear on either side are identical or close enough that I cannot tell a difference. Other than this though the mounts look fine. The rubber looks fine, they're not brand new or anything but definitely not blown or cracked enough to create the shift I am feeling.

  12. #12
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    IIRC the cradle bolts are 133ft/lbs torque. Could be that the cradle.shifted with all the power you're putting down. Couple that with a little bushing wear from one or more bushings, and there you may have a couple degrees of play. Do you have an alignment shop you trust? Maybe have them check it to see if the rear wheels are in spec.

  13. #13
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    Many years ago I had a 1995 Chevrolet Caprice with LT1 motor and 4L60E 4 speed auto.

    The rear would squat a little and sort of shift to the pass side.

    I don't remember which exactly bushing was bad, but only found out once a control arm was removed. I don't recall if I had to replace the arm or only the bushing.
    With everything bolted up, everything looked good and felt tight.

    It was only once the car was on a rack and we started to remove pieces is what we discrovered this.

    I know the suspension is completely different on these cars but this is just a tip that you may need to disassemble the rear to figure out exactly what's worn out and how bad.

  14. #14
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    Quote Originally Posted by 94cruiser View Post
    Many years ago I had a 1995 Chevrolet Caprice with LT1 motor and 4L60E 4 speed auto.

    The rear would squat a little and sort of shift to the pass side.

    I don't remember which exactly bushing was bad, but only found out once a control arm was removed. I don't recall if I had to replace the arm or only the bushing.
    With everything bolted up, everything looked good and felt tight.

    It was only once the car was on a rack and we started to remove pieces is what we discrovered this.

    I know the suspension is completely different on these cars but this is just a tip that you may need to disassemble the rear to figure out exactly what's worn out and how bad.
    I had a 9C1 Caprice that suddenly began locking up the rear brakes on acceleration. It turned out to be a broken(!) trailing arm. Closer inspection showed a little rust in the crack next to clean metal so clearly it had been cracked for quite a while and I finally broke it. The brake lockup was due to the parking brake cable pulling tight as the two halves of the arm separated. You gotta wonder what the cops did to crack that arm but you find all kinds of odd things wiht former police vehicles. Anyway obviously unrelated to OP's post but it's an amusing memory for me...and a very easy fix.

    Back on topic, I seem to recall a few members posting here that track their cars finding cracked/broken cradles, aren't the early years more susceptible to this? Memory is vague but I believe they said they couldn't tell until it was down out of the car.

    Richard
    06 Silverado ISS / 06 Silverado SS / 06 300C SRT8

  15. #15
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    I'm really trying to avoid dropping the entire cradle just to look for damage that might not be there. But it might be inevidable from the info I've received on here. I may look into getting a complete upgraded bushing set for the rear of the car, I think Petty makes one. That way I just change everything out to new and see what happens after.
    More info on the problem though, it seems when extra weight is added to the car, the movement is much less noticable. For example, I had my gf in the car over the weekend and tried to get the car to react so she could understand what I was talking about. It went from doing it everytime I accelerated hard by myself in the car, to only doing it after 1-2 shift and much less of a movement with the weight. I will add that although I am a 6ft 200lb+ guy, she weighs 110lbs soaking wet, so the added weight shouldn't have made that big of a difference. But it does make me think it has to be something suspension related.

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