83 Crossfire TA

iTrader: (2)

I have long sworn that you won't get wheel hop in these cars without something worn/broken/loose in the suspension... and for years I have never seen a car that was getting wheel hop that I didn't find something messed up when I looked.

Well, I think I found one- mine. It only seems to do it with 18's on the back (18x10.5 Z06 wheels with either 295 street tires or 305 drag radials). It is somewhat inconsistent, sometimes if I roll into the throttle in a higher gear it will haze the tires and in a lower gear it will sometimes just smoke the tires but others it will hop violently, honestly I don't know what the pattern is.

On slicks it won't do it doing a burnout or a launch at all.

Yea, it works well when it counts at the track, but it really kills the fun on the street/at car shows (I've been tempted to enter burnout competitions but haven't because of it).

It started when I added significantly more power, never did it before, but I didn't make any suspension changes between when it didn't and when it started. The the engine changes took about 70# off the front of the car making it sit slightly higher.

I have no idea what to try to fix it. Thoughts?

FWIW, Moser 9", 3.50 gears, detroit locker (I've had a few people swear that they had wheel hop with one and not without, not sure I believe that's the cause), stock springs, koni yellow shocks, modified jegster adjustable TA (mostly the bracket that bolts to the rear axle mounts to get it in tighter to the axle to clear the floor pan, stiffer than original and same location up/down/fore/aft, just moved in tighter to the driveshaft with DS loop added to the front of the body mount bracket), adjustable LCA arms (poly bushings on one and rod ends on the other). The moser LCA and PHR brackets were extended with multiple bolt locations for both and braced. It still has a T5 in it, but I'm guessing it's not long for this world, what is supposedly a newish clutch (less than 5K miles) will slip if I floor it in 4th and 5th and i'm pretty sure it has in 3rd but not positive.

Orr89RocZ

iTrader: (20)

Whats the shock setting and lca angle? Thats only time i ever had wheel hop in these cars, lca angle and shocks

Jaysz28

iTrader: (30)

My first thought was LCA angle and shocks as well.

Since you have multiple holes on the moser 9", I would drop the LCA's down one hole and see/feel how it reacts.

How many miles on those Koni Yellows?

scooter

iTrader: (11)

I remember you saying that years ago and criticizing people for saying they had nothing wrong with the rear suspension and saying they had to have something broken or loose.

83 Crossfire TA

iTrader: (2)

Hey, I even admit to it in my original post.

I still stand by that. I suspect that when I do figure it out it will be something specific to something I changed.

I will stand by wheel hop shouldn't be affected by LCA pivot hole location unless the back pivot is so high that it's effectively causing something akin to spring wrap on a leaf spring rear (you'd have to lower the car impossibly far). i can try dropping them down a hole but:

1. With the insane, "stock '87 off the showroom floor 4x4" ride height that this thing has I doubt that it will help
2. based on how it acts on slicks (the back suspension barely moves) I don't think I want it hitting the tires any harder

The Koni's are old Koni rebuilds (probably done 10-15years ago) but have <5000 miles on them. I've only ever used them for AutoX so they would have been set full soft for that, but I'm pretty sure I put them on step tighter when I stuck the 9" in it (thinking something like this thing is heavier, maybe I'll need more dampening...).

Orr89RocZ

iTrader: (20)

All i know is lca hole fixed my problems when i went to a more aggressive shock like that.

Lca angle is soley responsible with getting separation of tire to fender on a drag launch. Thats what is driving tire down into ground and shocks help keep it down

83 Crossfire TA

iTrader: (2)

Well, you can see where they where and where and where they are now:





If anything the wheel hop is the same or slightly worse now.

Weird thing, those top holes are the original moser holes (I extended the moser brackets), I can't imagine what ride height those would work for (mine already sits like a 4x4 and in my second hole they're almost flat, in the bottom one they're about 1" down)

83 Crossfire TA

iTrader: (2)

In the process I went through the whole rear suspension again, nothing has any play with it with the exception of a slight bit in the front slip joint for the TA (nothing major, way less than stock).

I'm debating if it could be the shocks. Koni yellows tend to be on the stiff side even set full soft so I'd hate to pull them and tighten them. I know I'll be pulling them and softening the again later.

83 Crossfire TA

iTrader: (2)

I do have another thought- could it be the chassis? Has anyone put in subframe connectors and gotten rid of wheel hop?

Yes, I'm ashamed to admit that I've done a bunch of suspension and engine work to this T-top car and it still doesn't have subframe connectors. The chassis flex is somewhat excessive, I've had the hatch pop open once and one of the t-tops come loose while beating on it before.

Orr89RocZ

iTrader: (20)

My 91 had wheel hop when i put the turbo on. Only started when i put power in and lowered it and put in my old tokico shocks. Stock ones were blown out. Cured it with lca brackets and that car did not have sub frame connectors.

It might be the shocks but if your car sits like a truck you still might not have enough lca angle

83 Crossfire TA

iTrader: (2)

Is your '91 a t-top car?

I'm not sure what you mean by "but if your car sits like a truck you still might not have enough lca angle." The higher it sits the more angle you have. You can see from the pics that I have a lot of angle there (I still don't get what Moser was thinking of with the stock location).

Mine only started when I put the new top end/cam/headers in it (I don't dare to say how much power I added publically anymore, you probably know why ). I'm sure you've seen this video but this is the same exact suspension/car with the LB9 still stock in it, you can see it reacts well and it didn't have any wheel hop even with the same exact tires, wheels, suspension, shock settings LCAs in the middle hole (where I had them before I posted), you can also see how high it sits, those are 26" slicks, they're actually almost exactly the same height my 18's (305/35-18, they measure just over 26.5" tall). If you go high res/full screen you can see all my brackets hanging down and how big the gap is from the top of the tire to the lip:

SlickTrackGod

Its the tires. The sidewalls are too stiff and the car is grip-slip-grip-slip. It feels like wheel hop but it is not. You can not drag race or do burn outs on grippy low profile tires unless you just roast them. If you are going for traction they will intermittently break loose- thus feel like wheel hop.

Orr89RocZ

iTrader: (20)

I dont see how a tire will break loose and regain traction soon after during an acceleration run. I run a lot of low pro tires and never had this issue. They grip or they spin. No inbetween. I've had 315/35/17, 295/30/19's and 305/35/19's. street radial and drag radial. Been high 1.4x 60 on the 305/35/19 drag radial but they do have a softer sidewall than normal tires

It is interesting though. Not going to rule that out

rgauder

iTrader: (1)

The squeal of the tires does seem to show that SlickTrackGod is probably right. IMHO.

SlickTrackGod

I get chatter on my street truck all the time at lower speeds depending on the pavement quality. I run 295-45-19's on it. Never did this ion all the 15 years I ran 275-60-15's. If i just stab the throttle the tires will just spin and glaze into heat and thus no chatter coming into grip. Does it mainly on cold tires or mild operating temps on DOT low profiles.

Drag radials do have a softer longitudinal sidewall, but not so much lateral. They may be laterally stiff, but longitudinally they are meant to give. I have actually run a road course on Drag radials before, got out of the car (when the owner asked me what I thought- had helmets on so I yelled to him "I don't know yet, give me a minute") got out of the car and walked around it ten noticed "Drag radials" They feel like hey go flat in a corner then pump back up when the throttle is applied.

Trust me I kind of know a thing or two about tires.

SlickTrackGod

Here's that street truck sitting with about 5000lb on the left rear going "get this **** off me" pulling about a g in a corner. On bad pavement like that going straight with mild throttle they will chatter with intermittent grip from about 5-20mph. Smooth asphalt they will never do it.

83 Crossfire TA

iTrader: (2)

I'm not sure that this is the case. I'm pretty sure that it gets more violent as I give it more throttle. If I get a chance I'll test it tonight. FWIW, it's done it on 295/35-18 firehawk wide ovals (OK street radials) and some 305/35-18 Mickey Thompson DR's. It does not do it on 26x10.5x15 slicks (all 3 tires are very close to the same size, around 26.5" tall...). It did not do it with EXACTLY the same setup with less power (the stock LB9) like in that video

Like I said when I posted it, that is an old pass with the stock 305 engine but EXACTLY the same suspension and on slicks (just to show how the suspension reacts). That combination never wheel hopped even on the same 18" tires. With the only change being adding power now suddenly I have wheel hop that only seems to happen on the 18's.

I guess the significant difference is that the stock engine couldn't just spin the tires rolling into it in gear at speed (maybe in 1st, I don't remember, otherwise I had to somewhat dump the clutch to spin the tires) where now it can in first, second and sometimes 3rd. AAMOF, I don't know that I've actually tried dumping the clutch with the current combination. Wheel hop gets so violent that I'm actually somewhat afraid of breaking things.

I'm not sure how them squealing coming out of the water shows anything since every car/tire I've ever seen come out of that burnout box sounds the same. I have something like 53 videos of different cars making passes that day that all sound like that if they spun out of the burnout box.

83 Crossfire TA

iTrader: (2)

Hopefully not to derail my own thread, but how did you like running it on DR's? Any idea which ones they were?

I hate the big wheel/low profile combination (maybe I haven't figured out how to set it up right) and have been seriously considering using something like 275/50-15 DR's on all 4 on this car for autox and street use. Maybe something like the Nitto 555r's, something a little stiffer/more street oriented than some other DR's (I don't know of any DOT really competent handling oriented tires made in those kinds of sizes anymore)

83 Crossfire TA

iTrader: (2)

yea, this is definitely not like chatter from going over sticky to non-sticky/bad surfaces (a perfect example is when launching at a stop light and spinning over the painted street striping, not that I'd ever do anything like that)

rgauder

iTrader: (1)

It was the squeal coming off the line, after the burnout I was talking about. Sounds like you're on the way to figuring it out though.

Orr89RocZ

iTrader: (20)

Does it change if you change the shock settings?

83 Crossfire TA

iTrader: (2)

I am? What makes you say that?

I mean I figured out that it's possible it was there before and I just didn't have the power to cause it but I don't even know that is the case. To test that I'd have to go out and dump the clutch and see what happens.

FWIW, I thought that I might get a chance to test it tonight but with the storms coming through I don't have much hope for it to be dry enough for to get conclusive results... around here it's pretty hard to even find a spot out of the way enough that you don't get hassled on a good day...

I have no idea. Koni's rear shocks are a royal PITA to adjust, you have to take them off the car to mess with the settings.

83 Crossfire TA

iTrader: (2)

Well, now I'm even more stumped. I drove it to the gym last night. I tried dumping the clutch, I tried rolling into it in 1st, 2nd and 3rd (I honestly couldn't tell if I was hazing the tires or the clutch was slipping in 3rd).

I finally did a close to 300' second gear burnout across the gym parking lot after it closed.

By the time I got it home the tires were warm enough that every piece of gravel I ran over was sticking to them and tinkling off the wheel well/quarters.

NOT ONE HINT OF WHEEL HOP...

The only change I've made since the last time I had wheel hop is I added an electric cutout to the exhaust. I haven't touched the suspension, tire pressure, temperature was pretty close to the same (though it was damp, the road surface was dry but everything felt damp from the rain we got earlier evaporating off and then cooling at night). I even tried opening and closing the cutout to make sure that didn't change something- the 300' of black marks at the gym was done with it open, it looked and sounded very John Force...

This makes no sense...

QwkTrip

iTrader: (22)

There was a change.... road surface.

83 Crossfire TA

iTrader: (2)

Ok, the road surface is never exactly the same 2x, but I'm positive that this has happened when it was more damp and drier than it was last night, and I've definitely had it happen in the same gym parking lot (one time so violently that I got out of it immediately and stalled the engine in front of a buddy of mine).

This isn't like it was doing it every once in a while, it was like every time I tried any hooning on the street tires I got violent wheel hop and then all of a sudden last night it just stopped. I drove it to a friends house, from there to the gym, back to a friend's house, and then back home, messing with it every chance I could driving like a complete jackass and I didn't have any little sign of it the whole night. It's not like I tried it once or 2x last night, it was like I tried it a few times in the neighborhood, when I was pulling out onto the main road, most intersections (where I was reasonably sure there wasn't a cop around/too many cars), in the other neighborhood, the gym...

SlickTrackGod

Yep, what I call tire chatter. Some surfaces will do it when tread catches intermittently. The lower the sidewall he more prone to this.

Crossfire, As for DR's on autox? I just explained above in a post that the one time I tracked a car with DR's on the rear of it (not knowingly- I jumped into an acquaintances car wanting me to give input) the grip went away and the rar tires felt like they were going flat and wallowing into and around the corners...and then would pump right back up. I noticed under a heavy trail braking they responded just a tad better if I kept the throttle taunt but was scratching my head after 2 laps. I slowed up to come off course and that's when he yelled through his helmet asking me what I thought and I told him I don;t know yet, give me a minute and I pulled the car intot he pits for a look. Got out and walked around with a real puzzled look on my face from something I had never experienced before and was scratching my head looking for a rear tire that was low on pressure- Thats when I saw they were DR's and said <Aw f*ck Raul, you trying to kill us in a half laughing half serious matter.

No I would not put DR's on a car for autox, you would be better off riding a bicycle on ice.

Also a side note. For some reason over the years I have seen many people refer to me as since I am more of a road racer that probably do not know anything about drag cars. Nothing further from the truth. Chassis dynamics is just that. It does not matter what you are doing to a car the settings are all the same tools.
I also ran the largest NHRA sponsored car show for 10 years, Drag raced VW's years ago, and owned a 10sec Vette on a road race setup. I have countless friends in the Drag world including Dave McLellend, Jim Campbell, Gman from Racetrans and I have been good friends for 30 years(Even sponsored my race car), Steve Gibbs was a friend for years but lost touch, same with Mike English (Cone Chevrolet fame- also sponsored one of my race cars), (Bob and Mike Hayes- Hayes clutches and Centerforce Clutches- Sponsored my race cars AND I developed the first prototype Centerforce Dual Friction Clutch in my race Vette),and Eric Lotts marketing director for the NHRA. I use to handle the race car side of the car show and if you can imagine was always up close and personal to about 70 top level cars and crew. I've been around some serious drag cars in my day.

I even worked in a Gas Station in High School right by John Forces house and shop. Back in 1984 he and Austin Coil and two others come into the gas station (which they did regularly) in Johns old POS station wagon and left it running while he started pumping gas. I asked him to shut the car off or I would have to turn the pump off (My boos was there looking out the window and we had rules) He did not comply so I shut the pump off and told him thank you but you can not get gas with a running vehicle. He puts the pump away. leans into the car and grabs a buck and slapped it on the pump I was standing on the other side of and then spits at me...I had a can of WD40 in my hand cleaning the stainless pumps so I doust him in the face with it. I've had the pleasure a few times over the years laughing about that story the couple of times we've crossed paths. (Im much bigger then he is now...lol)

QwkTrip

iTrader: (22)

Drag radials will be destroyed during autocross. The construction of the tire just won't stand up to it. Not even sure road tracks will even allow a drag radial?

The Nitto 555R on the other hand is a sorry excuse for a drag radial and that's why people use it for autocross. Let's just call it a performance street tire.

83 Crossfire TA

iTrader: (2)

Honestly for a long time I felt that the 555R was the best all around "street" tire that you could make good passes on at the track. I had a set of 275/40r17 on my '97 WS6 that I got over 22K miles on and ran 1.6's at the track with a stick.

I can't think of another truely streetable tire that can do both of those, but I'm not sure how many newer tires are close.

Honestly I kind of like the 295/40r18 Firestone wide ovals on my '87 TA. I haven't run them at the track since I've had enough power to run below 1.8's, but from the way they feel they are likely only a little behind the 555r's in a straight line and ahead in handling.

83 Crossfire TA

iTrader: (2)

FWIW, I haven't been able to reproduce it. I even did a monster burnout (in front of a friend's house, he swears it was almost 1/8 mile, we both wish we had video) without a hint of wheel hop.

I can't explain it, I can't think of what I have changed.

Orr89RocZ

iTrader: (20)

I have to say i would need to see it to believe it lol i ran 315 nitto 555r and couldnt hook better than a 1.83 with a bolt on ls1 car. Swapped to a 315 nitto nt05R, a true drag radial, and instantly went 1.66-1.67. No other change and that was all with a stalled auto car. Which is easier to launch and softer on tires on the hit