Can Dyno's damage cars?

[BlownLS7]

had my car on a dyno dynamics dyno the other day,
was unable to get reading due to a few factors,
1/was slightly raining ,dyno was wet.
2/car was not held down properly.

but while car was ramping up around 3-4000 it suddenly started to go heywire,the wheels were starting to rotate inside the rubber,,,,,

take 2 saw tyre pressure up to 50psi ,, same problem,

so after a failed 3rd attempt and my gut feeling that major damage was happening. asked them to pull the plug.

they said, due to suspension being so firm that was 1 issue,
water on dyno was another.(was not a factor on first 7 cars)

now to the damage i felt was happening.

car now has shocking vibration at approx 120-125 klm

anyone have any thoughts as to why this happens?

cheers

[Martin_D]

Bowlerr,
Dynos dont damage cars....dyno operators damage cars :teach:
That being said, with a couple of hundred plus kilowatts of load being transferred between the tyre surface and the roller any moisture that was present wont be for very long, as it will be evaporated via air drag of the roller spinning, and the heat of the power transfer :)

The wheels (rims) won't and cannot spin inside the rubber on a dyno unless there is something very very wrong, or to put it in context I havent seen this in 15 years of running chassis dynos. Wont say it cant happen, but its highly unlikely. Your vibration is more than likely an inexperienced operator applying the brakes when he/she felt the car wheelspinning and locking the rear wheels (easy to do) flatspotting the tyre agains the roller....seen it done many times :cool:

[hyper24]

Whatever happended it threw your wheel balance out of wack hence the vibrations at speed. Lucky its an easy fix.

[BlownLS7]

Bowlerr,
Dynos dont damage cars....dyno operators damage cars :teach:
That being said, with a couple of hundred plus kilowatts of load being transferred between the tyre surface and the roller any moisture that was present wont be for very long, as it will be evaporated via air drag of the roller spinning, and the heat of the power transfer :)

The wheels (rims) won't and cannot spin inside the rubber on a dyno unless there is something very very wrong, or to put it in context I havent seen this in 15 years of running chassis dynos. Wont say it cant happen, but its highly unlikely. Your vibration is more than likely an inexperienced operator applying the brakes when he/she felt the car wheelspinning and locking the rear wheels (easy to do) flatspotting the tyre agains the roller....seen it done many times :cool:

thanks for reply,do you think it will only be wheel balance?

[SOBSE]

Bowlerr,
Dynos dont damage cars....dyno operators damage cars :teach:
That being said, with a couple of hundred plus kilowatts of load being transferred between the tyre surface and the roller any moisture that was present wont be for very long, as it will be evaporated via air drag of the roller spinning, and the heat of the power transfer :)

The wheels (rims) won't and cannot spin inside the rubber on a dyno unless there is something very very wrong, or to put it in context I havent seen this in 15 years of running chassis dynos. Wont say it cant happen, but its highly unlikely. Your vibration is more than likely an inexperienced operator applying the brakes when he/she felt the car wheelspinning and locking the rear wheels (easy to do) flatspotting the tyre agains the roller....seen it done many times :cool:

Spot on. I have also seen a new engine go bang due to a operater getting a fat over the car he was in . Only take it up to 7200.......

[hyper24]

Who knows, but it only cost a few bucks to get fixed.
If the rims really did rotate inside the rubber then the weights for the balance would be way off.

Normally when the front wheel balance is off you feel it shake through the steering wheel and when the back wheels are off it shakes more through the body of the car.

[Hi-Torque]

What martin said is 100% correct, the only other thing i have seen after a dyno session, is the weights come off the inside of wheels this will cause a vibration

[bwhinnen]

Exactly as above the dyno operator should know better than trying to continue. Is this a new shop in town? Unusual operations for most of the dyno operators I know around the place.

Let us know how it goes. Was this on Saturday?

[Martin_D]

What martin said is 100% correct, the only other thing i have seen after a dyno session, is the weights come off the inside of wheels this will cause a vibration

And when they come off.....they are like bullets, made of lead, and travelling at high speed. EXTREMELY dangerous :teach:

[awddynotodd]

On BIG power stuff I have seen a tyre shift slightly, I'm talking well over 700RWKW. The guys who are aware of it just put a small paint texta mark on the rim and tyre and see where it goes to keep track of it, on a Supra with over 40PSI I saw one recently that had shifted about 10-12mm on the rim.

You may now have what I call "keywayed tyres", if the dyno operator hit the brakes a bit too harsh on the Ramp decel, it is possible to lock the rear wheels and the rollers keep spinning due to their inertia, instant half moon key way.

This is why we have a operator selectable Ramp Down rate, so the dyno actually slows the car down to whatever the start speed was. We don't just drop load at the end of the test like some and rely on the operator to have to use the brakes to slow the vehicle down.

[10sec_rx7]

And when they come off.....they are like bullets, made of lead, and travelling at high speed. EXTREMELY dangerous :teach:

yep the back wall of our dyno room is covered in dents... a few have actually gone through the 1.2mm alloy sheet...

and people wounder why we shut the doors and dont let them stand in the room...

[Ron SS]

Tyres moving on the rims can happen. I had a VX that did it regularly and needed the tyres refitted again to solve it. The VEs should be much better though as the big fix was to change the inner rim design. Put a chalk mark near the valve and check it after a few hard takeoffs ...they can move sometimes. Big power and there is only friction at the bead stopping tyres moving on the rims. As others have said, the balance weights may have also flown off. What were your tyre pressures at the start of the run?

[BlownLS7]

Tyres moving on the rims can happen. I had a VX that did it regularly and needed the tyres refitted again to solve it. The VEs should be much better though as the big fix was to change the inner rim design. Put a chalk mark near the valve and check it after a few hard takeoffs ...they can move sometimes. Big power and there is only friction at the bead stopping tyres moving on the rims. As others have said, the balance weights may have also flown off. What were your tyre pressures at the start of the run?

they were 36 psi,then pumped to 50psi


Exactly as above the dyno operator should know better than trying to continue. Is this a new shop in town? Unusual operations for most of the dyno operators I know around the place.

Let us know how it goes. Was this on Saturday?

mate this is not a new shop ,and truthfully im not about to disclose them,i can asure you i dont care to get up them as i feel it was done in good spirit and maybe operator was at fault (yet i wouldnt have a clue.),it was more about bending or breaking things,and it seems to be the consensous that its the balance,so tomm i will have them rebalanced then give a try on the freeway

cheers

[bwhinnen]

Na not asking you to disclose anything, was just surprised is all.

50PSI is pretty standard for shootout mode on a DD. Most operators will pump them up to this on a bigger car like ours.

[Mungrel]

Not good man, it looked bloody nasty from the side, on the 3rd time, i seen the wheels wobbling like crazy i almost lept through the wall to take cover!

As for what the cause of the new vibration is, worst case scenario could be a damaged CV, or best case scenario could just be a wheel weight (which i think we would have heard fly off) or just a wheel alignment.

hope its sorted soon though mate.

[MYTO8]

yep the back wall of our dyno room is covered in dents... a few have actually gone through the 1.2mm alloy sheet...

and people wounder why we shut the doors and dont let them stand in the room...

I actually had fly off on the first run in my new dyno room poped a nice hole through layer of 12mm gyprock 4mm fibro and layer of sound bats lucky hit steel door behind to stop it not happy had to repair it straight away. As Dale said good reason people shouldnt stand around cars on dyno.

[iamhappy46]

Tyres moving on the rims can happen. I had a VX that did it regularly and needed the tyres refitted again to solve it. The VEs should be much better though as the big fix was to change the inner rim design. Put a chalk mark near the valve and check it after a few hard takeoffs ...they can move sometimes. Big power and there is only friction at the bead stopping tyres moving on the rims. As others have said, the balance weights may have also flown off. What were your tyre pressures at the start of the run?

A lot of tyre fitters do not prepare the rim correctly when fitting new tyres. Wire brush to remove old rubber and get the bead to seal is an often overlooked step but in the same breath, some new cheap rims have an odd bead seat profile.

[BlownLS7]

A lot of tyre fitters do not prepare the rim correctly when fitting new tyres. Wire brush to remove old rubber and get the bead to seal is an often overlooked step but in the same breath, some new cheap rims have an odd bead seat profile.

Hi
new rims,(not cheap chinese, Made in Italy)
no old rubber.

thanks but none of these are factors

[vyss2ute]

Shop wasn't in Moringside was it?

Not pointing fingers but just curious...

[Mungrel]

Shop wasn't in Moringside was it?

Not pointing fingers but just curious...

Thats a negative.

[bwhinnen]

Shame it wasn't widely advertised, would have loved to pop in for a looksie... Keep us updated (even if via PM) on the next one.

[zorro]

it wasnt an LS1 affair, the Aus300zx guys had it organised and one of my mates invited me and a couple of others.

Shame to hear that Paul, I was a bit worried watching the shake from the rear end. My observations was no brake was used and it was put into neutral. I reckon a wheel weight could have come off or maybe as a result a bush could have deformed.

On a whole though was good to be the heroes of the day, Mungrel had me by about 10hp. If Paul got a number we would have all looked silly hahaha

[BlownLS7]

had car on hoist today just to make sure all was in order,and it was,so off to tyre shop.
result was rear left lost its weight,tyre was 60 gram out,
bad news was tyre was now OUTOFROUND,they are 4 weeks old Toyo T1r,and had done 1900 klm
now i ask ,can a dyno do this to a trye?

cheers paul

[Martin_D]

Thats the crazy nature of 'recreational motorsport' dyno days...on the edge looking for that last horsepower to claim the ultimate forum prize and BAM a wheelweight comes off! :eek: :lol: :diddy:
Sure beats crossing up and bopping the wall through the traps though :lol:

If your tyre is out of round....its been locked up against the rollers. Zorak SS might have missed the point here, unless the dyno is a Mainline and has a 'ramp down' auto speed built in it may have well taken 5 - 7 minutes for the car to freewheel to a stop in 'N'. Hence the brakes WERE used or it would have been one long dyno day with each and every car coasting laboriously to a stop :teach:

[Mungrel]

At least the cause of the problem is found.
I didn't hear (or feel thank fark) any ricochets of the wheel weight which begs the question... where did it go? :lol:

[Y55-7UT]

so with the deformed tyre are you able to try get the work shop to cover costs....otherwise its a nice excuse for a burnout to smooth it out:dancenana:

[BlownLS7]

Thats the crazy nature of 'recreational motorsport' dyno days...on the edge looking for that last horsepower to claim the ultimate forum prize and BAM a wheelweight comes off! :eek: :lol: :diddy:
Sure beats crossing up and bopping the wall through the traps though :lol:

whos looking for the last horsepower? i was invited along to a dyno day,felt that things didnt go well and asked a question,your attempt at calling me or others dyno queens is poor.(well thats the message written in snowtown hieroglyphics) im not on the edge of anything.as a matter of fact i dont give a rats about it,my judge will be when i shove it down WB on sat.
then im sure you will be able to tell me the HP without stuffing it up on a dyno?
and are you offering a forum prize of some sort? cuz you would owe mungrel..!!

by the way how is all the DYNO testing on those mercs you beat off on?i hope you givem back detailed?:nyuk:

so are you saying the dyno operator caused the tyre to be outofround?

no need to reply as i wont have time to respond as i need to go to hair and makeup,
:nyuk:
cheers paul




[quote=Y55-7UT;1275997]so with the deformed tyre are you able to try get the work shop to cover costs....otherwise its a nice excuse for a burnout to smooth it out:dancenana:

i dont think the tyreshop will give me a refund.nor do i think its right to ask ,its all part of Thats the crazy nature of 'recreational motorsport' dyno days.......... lmfao.....
i just need to put it down to experience,and remember to go to trusted workshops that have had exp in working with quality stuff.
i can drive on tyre up to 120ks so it will be ok for a while.
cheers

[iamhappy46]

i dont think the tyreshop will give me a refund.nor do i think its right to ask ,its all part of Thats the crazy nature of 'recreational motorsport' dyno days.......... lmfao.....
i just need to put it down to experience,and remember to go to trusted workshops that have had exp in working with quality stuff.
i can drive on tyre up to 120ks so it will be ok for a while.
cheers

Beaurepaires and a few other suppliers have a tyre warranty($7 per tyre) which would have allowed you to replace it for free, I got a puncture in my Dunlop SP Sports which tore the sidewall and got them replaced at no cost :)

[Martin_D]

by the way how is all the DYNO testing on those mercs you beat off on?i hope you givem back detailed?:nyuk:

With four round tyres too :)

To summarise, so the facts dont get lost in the mix -
1) Wheel weights can come off on dynos - so dont stand in the 'firing range'
2) Knuckle heads can look the wheels up and flat spot tyres on dynos - owner beware
3) Tyres dont deform or 'go out of round' on dynos

[zorro]

To summarise, so the facts dont get lost in the mix -
2) Knuckle heads can look the wheels up and flat spot tyres on dynos - owner beware


From what I saw there were no wheel lockups on the dyno by any car, including Pauls, unless the lockup was in microseconds.

There was no prizes or a wall to piss on during the day worlds apart from that. Considering everyone was talking cars and other shit, no bagging of imports vs. V8s and noone at any point was too concerned at what power their cars made I wouldnt call it 'recreational motorsport'. Better than other dyno days where i have been to where most have their heads up their ass and the shop in question apends the day trying to sell you products/services.

Anyway this is going OT, Tuna you and others answered Pauls question. Its good we have the experience of operators here to help out when needed.

[Martin_D]

It would be very interesting to see the tyre....if its out of round...and not flat-spotted then its a warranty issue :teach:
It does however take less than a second to destroy a tyre on a dyno...it happens very very quickly and in most cases not even the operator has any idea its occurred :)

[SS Enforcer]

Out of round is a tyre manfacturing issue, flat spotting is skidding of the tyre causing it to wear prematurely somewhere. 60 grams is a fair bit of weight to put on a high end wheel and tyre combo.

Hows the locating rings on the car Paul are they a really tight fit. Mine vibrated and were only out of whack .1mm they were 67mm instead of 66.9 mm. Once that was sorted they ran nice and smoothly.

cheers

[Crusty]

Out of round is a tyre manfacturing issue, flat spotting is skidding of the tyre causing it to wear prematurely somewhere. 60 grams is a fair bit of weight to put on a high end wheel and tyre combo.

Hows the locating rings on the car Paul are they a really tight fit. Mine vibrated and were only out of whack .1mm they were 67mm instead of 66.9 mm. Once that was sorted they ran nice and smoothly.

cheers

I was thinking that myself... a high quality rim and high quality rubber matched and fitted correctly shouldn't need 60gm's of weight I would have thought? My cheaper rims and tyres certainly don't have that much at all.

[BlownLS7]

Out of round is a tyre manfacturing issue, flat spotting is skidding of the tyre causing it to wear prematurely somewhere. 60 grams is a fair bit of weight to put on a high end wheel and tyre combo.

Hows the locating rings on the car Paul are they a really tight fit. Mine vibrated and were only out of whack .1mm they were 67mm instead of 66.9 mm. Once that was sorted they ran nice and smoothly.

cheers

Hi Paul
I had new locating rings fitted yesterday,the wheels fit up very nice to the hubs,the balance on all wheels required at least 30 grams,however driver rear req 60 grams.
the tyre does not have a flat spot,i have checked it 10 times.however im going back to check what the wheels look like spinning on the car.to see the balance on the hub.
as for actual ring size i cant get hold of steel rings,i could only get plastic,and the tyre fitter said he would not fit aluminium cuz they will never come off ? (due to?)
there is a place in springwood called wheel revoloution that makes custom bits for wheels and i will get some done there soon.

cheers

cheers

[MR-GEM]

scary to hear...hope this isn't a common thing.