Have you ever broken anything during a launch?

[thor'svr4]

I did a quick search on this forum and didn’t see any thread that discussed the breaking point of drivetrain components so I figured I would start a thread on it. It might be a good idea to get together a ‘list’ of what people break at what hp/tq. This information would defiantly be useful for anyone whose new to the 3000gt / stealth platform.

So like the title says, post up your experiences. Good or bad. If you have broken a part let us know what you broke. How much hp/tq? What rpm did you launch at? Ect. But equally as important as knowing what parts will break is what parts will hold. Let us know about any parts that have surprised you.

My contribution:
418/408 awhp/tq
Solid motor mounts
Stock OEM clutch, stock flywheel, stock 25 spline t-case with maximal ‘old style K’ brace.
~7000rpm launch on brand new Kumho Ecsta MX 245s deflated to ~20psi at the track.

The only issue I’ve ever had was this thing

http://i366.photobucket.com/albums/oo110/streetracer4688/part1.jpg

I heard a weird noise right after the launch and I initially thought I had broken something in the trans and when I pulled the trans apart I saw that this part was purple and 4 of the 6 gears in it were seized. (turned out the noise was a spun #6 rod bearing) The car drove perfectly fine on the way home from the track. To be honest I’m not sure if I killed the part with all the launches or if the part had been seized ever since I bought the car. When I bought the car it had no oil in the trans, t-case or rear end. It is interesting to note that it was the cars first drive with Pennzoil synchromesh in the trans.

Other than that I’ve never had a single issue. So far I’ve done a few hundred street launches and ~8 launches at the track on the stock drive-train.

From my personal experience (which is obviously limited to my vr4) I would say a stock first gen 25 spline drive-train with Maximal Performance transfer case brace is plenty strong enough to hold low 400’s. I’ve got no idea how it would do on wider street tires, drag radials or slicks though.

[mb3000]

Does my neck count? :p

[thor'svr4]

Does my neck count? :p

those are always the first thing to go, along with your passengers bladder and there ability to refrain from screaming like a little girl lol.

[Ninja Performance]

I have broken 5 spd TCs ( think 4 or 5) , a 6 spd TC (pinion), 3 rear axles, 3 transaxles.

-Chris

[FeaRpb]

I have broken 5 spd TCs ( think 4 or 5) , a 6 spd TC (pinion), 3 rear axles, 3 transaxles.

-Chris

Hey Chris, was it only the driver side rear?

[thor'svr4]

I have broken 5 spd TCs ( think 4 or 5) , a 6 spd TC (pinion), 3 rear axles, 3 transaxles.

-Chris

how much power did it take to break the transaxle? im pretty surprised to see that you've killed 4-5 5 speed t-cases yet you haven't broken any output shafts? i always assumed the breaking point of the t case was similar to the breaking point of the output shaft.

also has anyone ever blown a rear end? it seams pretty common for RWD guys to talk about switching out there stock rear end for a larger one. ive been asked by several 'domestic' guys what ive got for a rear end in the car and they always seam surprised to hear that its just stock.

[Ninja Performance]

how much power did it take to break the transaxle? im pretty surprised to see that you've killed 4-5 5 speed t-cases yet you haven't broken any output shafts? i always assumed the breaking point of the t case was similar to the breaking point of the output shaft.

also has anyone ever blown a rear end? it seams pretty common for RWD guys to talk about switching out there stock rear end for a larger one. ive been asked by several 'domestic' guys what ive got for a rear end in the car and they always seam surprised to hear that its just stock.

I have a 300M output shaft. And was running stock TCs. I know have a SS front and mid case with stock internals. Our rear end is pretty stout. Don't think anyone has broken one, not that I have heard of.

-Chris

[Ninja Performance]

Hey Chris, was it only the driver side rear?

Went to the track once, brought a pair of stock rear replacements like I always do. Launched, broke pass side. Replaced in pits. Launched, broke driver's side, replaced in pits. Launched, broke pass side and was out of axles to went home. Good times.

-Chris

[UTRacerX9]

I've broken a stock 5 spd TC, the front housing is pretty thin in a few places. I didn't completely shatter it, but it was enough to crack it in several places and for fluid to start leaking out. Upon opening it up, the bearings were toast. This was when I first got my 13T's. I've also stripped the splines on a 18 spline stock OS on my previous red TT.

[HellBringer]

Literally 100's of street launches and 60-70 or more track passes between a few different cars and never broke anything but a stock/original clutch. Unless you're making BIG power (600+ wheel) the guys breaking shit left and right need to adjust their launch technique. The only excuse for breaking shit at BPU levels is the driver and/or using an overkill clutch. Granted, sometimes shit happens and something breaks unexpectedly, but generally the drivetrains in these cars are stout; however, they are not tolerant to poor technique.

[Ninja Performance]

I ride the clutch until all slack is taken up and I start rolling out then I dump it.

Unsprung hub clutches. 4+ and 5

-Chris

[stealthee]

I don't want to think about the answer to this question.

Friggen glass non turbo transmissions. :mad:

[KeithMac]

Apart from roasting a few clutches I`ve broken nothing while launching my 1st Gen 18 spline tranny.

Solid mounts and Maximal bracket have worked wonders for 200+ launches.

[J. Fast]

I broke this.
http://img30.imageshack.us/img30/5149/april2009167.jpg (http://img30.imageshack.us/i/april2009167.jpg/)

http://img198.imageshack.us/img198/8712/april2009134.jpg (http://img198.imageshack.us/i/april2009134.jpg/)


But I make less power than stock.

http://img64.imageshack.us/img64/1593/april2009126.jpg (http://img64.imageshack.us/i/april2009126.jpg/)


Steve

...and you broke that when and how? At how much boost? What do the ring and pinion bearings look like? I bet $100 there's a machined bearing race in that transmission from the a bad bearing or the bearing preloads being out of spec. 99.9% of the time the only reason why teeth bind in a helical gearset is if the end bearings are damaged or poorly maintained. You never put down enough power to excite the gearbox enough to collapse a bearing cage or crush a bearing sleeve or collar in that 0.1%'th tile... so put those pictures away.

That fracture is not from power, it's from poor maint, bad launch technique, possibly stupidity... or any combination of the three, really. Hence, should not be included in discussion.

First post summation... What did you break and at what power level? You broke that on a 12 sec car... please fool :rolleyes3:! Exclude from discussion as to not skew results

[thor'svr4]

...and you broke that when and how? At how much boost? What do the ring and pinion bearings look like? I bet $100 there's a machined bearing race in that transmission from the a bad bearing or the bearing preloads being out of spec. 99.9% of the time the only reason why teeth bind in a helical gearset is if the end bearings are damaged or poorly maintained. You never put down enough power to excite the gearbox enough to collapse a bearing cage or crush a bearing sleeve or collar in that 0.1%'th tile... so put those pictures away.

That fracture is not from power, it's from poor maint, bad launch technique, possibly stupidity... or any combination of the three, really. Hence, should not be included in discussion.

First post summation... What did you break and at what power level? You broke that on a 12 sec car... please fool :rolleyes3:! Exclude from discussion as to not skew results


You don't know the facts so you're only guessing, The whole gearbox was trashed (except for the output shaft). Yes it was done on a launch. With a launch, there's bugger all boost unless you've got launch control or similar. I dropped the clutch at 5 or 6 K or whatever. The car didn't even move off the line, was the 3rd launch of the day.
Yes, you're partly right, the gearbox had been rattling for a while. I'll let you work it out.

So how much power does a car make with no load in neutral at 6K?

Steve

i wasnt going to say anything but since J Fast already brought it up... the point of this thread was to hopefully get a relatively good idea (and hopefully a nice list that i can update in the 1st post) of what is going to break and at what power level. ill take your word that you broke it during a launch, but why post it in a thread discussing what will break at XXX hp when the only reason that trans broke was because of problems unrelated to power. that trans should have held that power + a whole lot more.

[thor'svr4]

For fucks sake this was supposed to be an informative thread that people could use as a reference. A thread where REAL results were shown and discussed. Not where the village idiot comes to take a shit.


There's a difference between breaking something on the startline when the clutch is dropped and breaking something once boost comes up.

Yes there is, but if your going to break something in these cars its going to be during the launch. Nobody breaks something once there rolling.


The instant the clutch is dropped, there's no boost, the breakages are caused by inertia not power output. Just the same as most broken transfer cases are caused by broken engine mounts rather than high power output.

The higher powered cars above who've broken parts on the startline didn't do it with power.
They would have done it because of their lower tyre pressures and sticky tyres, totally unrelated to how much power they're making.


Close but not quite. Assuming you don’t have any sort of launch control or 2 step you will not be building boost with the clutch in at the line. Yes, it will take a fraction of a second for the engine to build boost. But it will also take a fraction of a second for the drivetrain to be under full stress because it will take a fraction of a second for the clutch to 100% engage. The instant the clutch is fully engaged your transmission’s input shaft will be at the same rpm as the motor, irregardless of the angular velocity of the tires or speed at which the car is moving. The stress from a launch does depend greatly on how fast the clutch fully engages. But it is also dependent upon the force turning the input shaft (force coming from the motor) and the resistance caused by traction, weight, friction, ect. So this begs the question, ‘what force is turning the input shaft?’ well the torque of a rotating system with no force opposing it is 0. For sake of argument lets just say that you launch at a constant rpm. Aka the car is at 5500rpm with the clutch in and once the clutch is released the motor is still at 5500rpm. Lets also say that under load on a dyno with resistance opposing the force applied by the motor you produce 500 ftlbs of torque at that rpm. That would mean that the amount of stress on the drivetrain goes from ~0 when the clutch is in and the car is at a stop to potentially ~500 ft lbs in the amount of time it takes for the clutch to fully engage and put the engine under load, provided there is enough traction to provide the ‘counter resistance‘. Thus the peak stress on the drivetrain doesn’t happen in the millisecond before boost, but rather once the car is at its peak power during the launch.
So the peak ‘potential’ stress during the launch is dependent upon the power that the motor makes. A loss of rpm’s during a launch will reduce stress. A loss of traction during a launch will reduce stress. Slipping the clutch for an extra fraction of a second will reduce stress. But nonetheless the peak stress is proportional to the amount of power the motor will make under load at that rpm.

This makes sense because it explains how someone with a 600hp nitrous mustang can launch on a stock drivetrain and not break anything… because there not producing 600 hp until they spray the nitrous. Thus there not asking there drivetrain to hold up to any more stress than a unmodified mustang. Yet if that same person were to launch and spray at the same time there is a higher chance of them breaking a drivetrain component.

Your statement on the other hand does not make sense. Essentially you are saying that all 3000gts on street tires undergo the same ’stress’ during a launch because the inertia caused by the rotating assembly is virtually identical between a bone stock 3000gt and a 1000hp 3000gt. You forget that that rotating assembly has a force causing it to rotate and overpower the drivetrains resistance. You cant really think that the force caused by ‘inertia’ a rotating assembly is enough to get a 3800lb car to move 60’ in 1.8 seconds… But even if it were true (just for sake of argument) that would mean that all the potential energy from the rotating assembly would have to be converted into the cars kinetic energy… which means your rotating assembly now has 0 ‘inertia’ and is not spinning… aka your motor is stalled. If you really think this is true then rev your car up and turn the key off right as you drop the clutch. Tell me what you get for a 60’ time.


Then again , once you get people selling parts which are designed to fix a certain problem, you get people telling lies, making misdiagnoses, in order to sell more parts which aren't needed and don't work.

A lot of the perceived ‘weakness’ from 3000gt tranny comes from people just like you who have no clue what there talking about. The truth is your setup doesn’t make nearly enough power to come close to being able to do that to a normal trans. I don’t care if you’re on a set of Mickey Thompson wrinkle wall slicks launching with a 2step and dropping the clutch at 7grand. the damage from that pic should not have happened, yet by you saying ‘hey I broke this’ in a thread about the breaking points of drivetrain components just implies that the stock drivetrain is made of butter.

And for any physics majors out there I apologize for the very crude terminology and am well aware that I used some terms out of place. it’s a bit difficult to try to convert everything in layman terms while retaining proper terminology. If someone spots a major error in my explanation, and you actually know what your talking about, just P.M. me and ill fix the mistake.

[UTRacerX9]

If I had to guess... Steve broke his bellhousing because he was missing a few bolts holding it to the block. I've seen the same thing happen with turbo eclipses at stock power levels, where they didn't have all the bolts in and tried launching it.

[Ninja Performance]

You missed the point.

There's a difference between breaking something on the startline when the clutch is dropped and breaking something once boost comes up.
The instant the clutch is dropped, there's no boost, the breakages are caused by inertia not power output.
Just the same as most broken transfer cases are caused by broken engine mounts rather than high power output.

Then again , once you get people selling parts which are designed to fix a certain problem, you get people telling lies, making misdiagnoses, in order to sell more parts which aren't needed and don't work.

The higher powered cars above who've broken parts on the startline didn't do it with power.
They would have done it because of their lower tyre pressures and sticky tyres, totally unrelated to how much power they're making.

Steve

I leave the line with 30psi+ boost. Before the clutch is even dropped I am at 30psi+
I have solid steel engine mounts. No, the aren't broken.
I have street tires.

Just because YOU don't have power doesn't mean everyone else doesn't.

-Chris

[Lugnut]

Traction .. And also my pride .. But wait, I promise this list will grow !!!!

[Checkered vr4]

I broke a Mark Williams 300M output shaft! it was an 18 spline shaft and I twisted it about half a spline and it ran fine for 2 years like that but at the begining of last year . . . BANG . . . followed by a 600+ hp front wheel drive burnout (I was running a custom spool in the center diff.) It was not at the track although I am sure the damage was done there. I run solid motor mounts, ss transfer case housing, cf driveshaft, and street tires. I launch my car by reving to 5000 and swiftly lifting my left foot (rps carbon-carbon) as I stomp the gas to the floor. My fastest 1/4 mile was 11.2@134 with a 1.8 60 ft. I havent seen a 1.6 60 ft. since I changed from dr500 to dr800 turbos.

[GTOJOE]

I think that's the only 300M I have ever heard of breaking.....

[stealthee]

Matt broke 300M rear axles. I think I have heard of a few other 300M OS's snapping, but I think I remember one such instance being blamed on a flaw in the casting.

[MR2]

not broken anything :p

spend to much money getting stuff beffed up for that to happen (shorly)

[IPD]

note that chris never said he broke an ATX during launch. that only happened when he shifted it into o/d. :p

[IPD]

Matt broke 300M rear axles. I think I have heard of a few other 300M OS's snapping, but I think I remember one such instance being blamed on a flaw in the casting.

i think it was established that those were NOT 300m axles. ray himself said they were not TRUE 300m axles. i'll let someone correct me if i'm wrong though.

[drew0u812]

In the 14 years of owning my stealth, the launches are countless and nothing broke. I have glazed the stock clutch several times, but nothing broke.
In the last year of my car's life I would pretty much do an all out 0-60 (4.01 sec) run at least once a week coming home from work and nothing broke.

[TAZmaniac]

Well ....
Not going to comment on the discussion about what is possible or not. My experience is that shit happens when you get enough torque and power ....

Personally I have broken this :
http://i112.photobucket.com/albums/n187/TAZ3kGT/Girkasseras/Davarkassaute.jpg
http://i112.photobucket.com/albums/n187/TAZ3kGT/Girkasseras/Alledelerfrahuset.jpg

Completely grenaded .... :eek5:

I have broken this :
http://i112.photobucket.com/albums/n187/TAZ3kGT/Aksel%20inn/Inngende.jpg

I`ve broken this :
http://i112.photobucket.com/albums/n187/TAZ3kGT/TC/TC4.jpg

And the second one that went ..... :
http://i112.photobucket.com/albums/n187/TAZ3kGT/TC%202/Transfercasegear.jpg

I`ve broken this :
http://i112.photobucket.com/albums/n187/TAZ3kGT/DHB%202009/Crackedendhousing.jpg

I`ve also ripped apart one of these (not that I`m the only one to have managed that ... ) :
http://i112.photobucket.com/albums/n187/TAZ3kGT/Clutch/27072007001.jpg

Everything I have done is also on STREET tires .... not even street slicks. Kind of tells me that I must have done SOMETHING right in getting the power to the ground right ???

Besides the things mentioned above I`ve also thrashed a Supercar dog-shift trans complete with Supercars center diff :( ... and completely cleaned out a second "reinforced design" RPS CC-clutch but those were just "following damage" from other causes ......

I`ve also "worn out" my RPS CC-pressure plate to tha degree that it started cracking by the mounting points for the springs .... (even though the rest was fine right Michael ? ) ...

So yes... things break .... It`s just very hard to set a certain amount of HP to decide what goes when .... It all depends on the use and the milage you put on it ....

(and a little OT .... yes I know Michael ... I`ve been a little busy for a while. Summer holiday time over here has just ended, rebuilding my kitchen and hallway, partly rebuilding the kitchen at my cabin etc etc .... I know I`m not the most reliable poster but I`m an expert in suddenly resurfacing once in a while :coo3l: )

TAZ

[MR2]

Yep, the plates seem fine Taz have not actually used them yet though :) glad to see your still around

of note on the plates, you've got some serious wear on the splines! :)

you ARE going to tell us how the new clutch is going right? and compare it to the old one?

[TAZmaniac]

Wear on the splines ... Hmmm wonder how THAT could have happened ?? :coo3l:

(I did tell you that there were some wear though .... but it never was any issue as long as I had them in. Didn`t see any wear on the axel so I figure I would have used them again. As this is your "spare" let`s just hope you`ll never have to use them ...)

And yeah I`ll put up a post comparing them in a short time. I have now done a LOT of daily use, a couple of drag launches and a day of circuit racing this weekend so I feel I have a pretty good opinion on it now ...

TAZ

[MR2]

Wear on the splines ... Hmmm wonder how THAT could have happened ?? :coo3l:

(I did tell you that there were some wear though .... but it never was any issue as long as I had them in. Didn`t see any wear on the axel so I figure I would have used them again. As this is your "spare" let`s just hope you`ll never have to use them ...)

And yeah I`ll put up a post comparing them in a short time. I have now done a LOT of daily use, a couple of drag launches and a day of circuit racing this weekend so I feel I have a pretty good opinion on it now ...

TAZ

No need to stress on the splines, still got plenty of KM left in them ;) just that they are worn down a bit (will take some photo's)

[hated]

Broke a transfer case w/in 60ft of a launch. That was a good day.