Precision Ind. DRAGON Torque Converter Blew UP

[jamesmost]

So my 2,800 stall Dragon Converter went B L A M O...in doing so blew the front seal on my trans & bent a spring in valve body.

Took trans out, and the tc shaft was worn awaytrans shop said tc must not have been true, runout was offthe hub must not have been centered.

I did have an odd rumble,vibration at idle ???

My flywheel and Dowel pins were in perfect true condition.

Installing a freshly rebuilt stock converter and sending back Dragon to Precieion, who says they will stand behind their procuct 100% if it was due to their fault, and if not $275 to rebuild.

they will install any updates they have for it.

should have car back 2morrow w/stock converter.

SO i had a 2,800 stall. thinking of bumping it up a Bit either to 3,000 or 3,200 or 3,400????

Anyone with the Dragon have the Higher stalls please chime in.

James
Modified by jamesmost at 4:56 PM 1/27/2009

[maxnix]

Man, that is not cool. What will they do for your blown front seals?
Modified by maxnix at 12:24 PM 2/2/2009

[Trumpkin]

I've got a 3000 stall. I like it but it is kinda hard to deal with sometimes on the highway. I went through so much with pre industries. They sent me two wrong converters. Finally got the right one. Go 3400-why not? The one I finally got was not one off the shelf. I have no vibration at idle.Was your vibration in gear?

[Q45tech]

Precision balance at 7300 rpm input is the key to long life. Few V8 automatics turn that high so they test at lower rpm and things fall apart.

Same problem with alternators and other auxillaries...............the step up ratios [pully diameters] are very unusual on Q so things must be perfect to last.

One of reasons the belts crack earlier than average low rpm V8 belts.

Try this calculator to see how fine the balance weight resolution should be"http://www.corvib.com/vibratio...r.cfm

At 7300 rpm you are dealing in the 30 milligram level if you are able to hold the ATF temperature within a very narrow range [+-10F] and viscosity.

Drain plugs result in a serious imbalance problem that is hard to compensate just as lockup clutch wear.

[jamesmost]

Man, that is not cool. What will they do for your blown fornt seals?

I am sure u know the answer to that i did not even ask did not want to create an adversarial position. hoping they fix / replace for free.i did remind him all the issues i was put thru in the past 3 wrong converters which = time and $$$$$$

[jamesmost]

I've got a 3000 stall. I like it but it is kinda hard to deal with sometimes on the highway. I went through so much with pre industries. They sent me two wrong converters. Finally got the right one. Go 3400-why not? The one I finally got was not one off the shelf. I have no vibration at idle.Was your vibration in gear?

well my 2,800 stall does not give me a hard time anywhere, so i guess ill stick with it...

what do u mean by hard time ??my vibration i think was bothin park and gear, i led myself to beleive it was the rumble of my highly modified exhaust ???James

[jamesmost]

I am sure u know the answer to that i did not even ask did not want to create an adversarial position. hoping they fix / replace for free.i did remind him all the issues i was put thru in the past 3 wrong converters which = time and $$$$$$

James

[jamesmost]

Precision balance at 7300 rpm input is the key to long life. Few V8 automatics turn that high so they test at lower rpm and things fall apart.

Same problem with alternators and other auxillaries...............the step up ratios [pully diameters] are very unusual on Q so things must be perfect to last.

One of reasons the belts crack earlier than average low rpm V8 belts.

Try this calculator to see how fine the balance weight resolution should be"http://www.corvib.com/vibratio...r.cfm

At 7300 rpm you are dealing in the 30 milligram level if you are able to hold the ATF temperature within a very narrow range [+-10F] and viscosity.

Drain plugs result in a serious imbalance problem that is hard to compensate just as lockup clutch wear.

Ill drop Precision a not to c what rpm they balance up 2.James

[Trumpkin]

well my 2,800 stall does not give me a hard time anywhere, so i guess ill stick with it...

what do u mean by hard time ??

Cruising on the highway the rpm's are up pretty high before lock up. Mine may be higher than 3000.

[jamesmost]

got car back on Friday with a stock rebuilt converter.Night and day, I can barely spin the tires and that is with the 408.Shipped out the Dragon to precision.

Bill was $900, which included a revolution sensor from infiniti.my 2nd one to date.

Precision should have the converter in by Fri,Sat or monday.Shall c what they have to say.James.

also have a leaking H2o pump just fyi

[Q45tech]

Spinning tires is a pure waste of acceleration. What one wants is the ragged edge just before they spin and lose traction.

[jamesmost]

Spinning tires is a pure waste of acceleration. What one wants is the ragged edge just before they spin and lose traction.

I agree, and that is almost what they are doing now with stock stall speed.

i do love to smoke them though.

maybe i should lower the stall on the PI converter maybe to 22 or 2300.James

[Q45tech]

2200 rpm is OEM stock stall speed assuming engine is producing correct amount of torque at sea level. Obviously the oem TC will stall higher as temperature drops from 70F depending on ATF/viscosity temp curve.

When ATF temp [inside TC] increases the stall speed will drop in summer or after repeat accelerations. [measure ATF just as it leaves TC] to see how really hot it is, not in sump where it is much cooler.

[jamesmost]

2200 rpm is OEM stock stall speed assuming engine is producing correct amount of torque at sea level. Obviously the oem TC will stall higher as temperature drops from 70F depending on ATF/viscosity temp curve.

When ATF temp [inside TC] increases the stall speed will drop in summer or after repeat accelerations. [measure ATF just as it leaves TC] to see how really hot it is, not in sump where it is much cooler.

Mine breaks loose much sooner then that more like 1500 -1800 rpm...

[jamesmost]

Man, that is not cool. What will they do for your blown front seals?

Modified by maxnix at 12:24 PM 2/2/2009

so precision shipping back my rebuild New Hub (runout was off) - that is what wasted my transthey updated my internals....$700 of the damage i contribute to themnot including the revolution sensor and driveshaft support bearing...700 includes $96 of synthetic M1the other $200 for rev sensor... which i guess is coinsidental...and $130 for bearing plus labor.....

[Trumpkin]

Wow, that stinks. I guess I have been lucky with mine.As far as spinning tires, with my dragon tc all I do is floor it and the tires smoke till it grabs! its fun. not economical!

[Johnny Rocket]

Whew........you guys are wearing my head out...."2200 rpm is OEM stock stall speed assuming engine is producing correct amount of torque at sea level. Obviously the oem TC will stall higher as temperature drops from 70F depending on ATF/viscosity temp curve"

Stall speed does not mean s***........I have spent about $50,000.00 thats right.........you read it correct........I have bought more convertors for racing than you can ever imagine....

Dont worry about the stall speed..........its the torque multiplication of the convertor that means something...

You talk stall speed to a real torque convertor guy and he will know your a newbie and tell you what you want to hear.....

Its kinda like talking airflow to a head porter......you start talking air flow in CFM numbers and he will hang up on you......its abot port velocity and volume for the cubic inch and rpm of the engine and a port with no turbulence

Torque convertor is the same kind of conversation...

Two convertors with the same stall speed may perform different....dont get caught up with Stall numbers

Here is my question......are they using your stock steel core and ripping you off by bending the fins ?

[Q45tech]

Why we have so few engineers here and those that stop by run away screaming after readung a few posts.

Hopefully they test MR and report as identical build units can have differences depending on final assembly tolerances.

The problem is often from trying to simulate the VH45 engine torque curve due to 32valves having lower torque at or near stall speed than say a 265-307 16 valve V8 of similar displacement [274 ci].

[Johnny Rocket]

Where is the first torque peak in the vh45 engine?

Ideally thats where you want the convertor to FLASH too.

Foot Brake to view Stall Speed is wrong.

The tires cant hold it long enough to obtain true stall.....a transbrake will work but nobody is going to do that.

I would be curious if we could get a poll on flash converter stall rpm

Simple test.......get on drive pavment and be stopped and mat the gas pedal as fast as possible to the floor and stare at the RPM's and see where it immediatley rises too and then slows down and makes the car move.

I have done that to Elwesso's Q and its right at 2800 RPM ( Flash RPM)

I have no clue of where peak torque is on these cars but a chassis dyno might help.

Thats where you want a street convertor to work with not much slippage.

My understanding is there is two torqe peaks......I am sure the bottom tP would be perfect.

[elwesso]

first torque peak is at 4000 RPM.

[jamesmost]

Not just a tweaked stock converter.... all billet and heat treated metals, patented custom clutches, very little inefficiencies at highway speeds.and like stated with a minimal bump in stall speed mine is 2,800 the tires can easily be lit up...James

Whew........you guys are wearing my head out...."2200 rpm is OEM stock stall speed assuming engine is producing correct amount of torque at sea level. Obviously the oem TC will stall higher as temperature drops from 70F depending on ATF/viscosity temp curve"

Stall speed does not mean s***........I have spent about $50,000.00 thats right.........you read it correct........I have bought more convertors for racing than you can ever imagine....

Dont worry about the stall speed..........its the torque multiplication of the convertor that means something...

You talk stall speed to a real torque convertor guy and he will know your a newbie and tell you what you want to hear.....

Its kinda like talking airflow to a head porter......you start talking air flow in CFM numbers and he will hang up on you......its abot port velocity and volume for the cubic inch and rpm of the engine and a port with no turbulence

Torque convertor is the same kind of conversation...

Two convertors with the same stall speed may perform different....dont get caught up with Stall numbers

Here is my question......are they using your stock steel core and ripping you off by bending the fins ?

o

[Q45tech]

Actually the engine torque is pretty flat after 3,000 rpm but peaks at 4,000 depending on air temperature [tuning in plenum/runners].

You cannot use chassis dyno graphs because the TC and gears friction losses increase with rpm and depend on the rpm divergence between the stator and impeller.

You can graph this by data logging the turbine sensor rpm vs engine rpm during various loads of acceleration.

[Johnny Rocket]

all billet in my mind this is doubtful....most of the all billet as you say means the case etc. Why it blew up is anybodys guess but I would be curious as to what did fail.....?

The flat torque curve is good of course so 3000 rpm would be perfect if the convertor was tight enough.....some stall there and feel loose as a goose and not very efficient......the convertor El Wesson oil has felt almost perfect for a dailey driver.......

If you were racing one of course 4000 would be perfect for a drag car...but 2800 is pretty darn good.

I think a smaller convertor tighter might even be better....you can achieve a higher stall speed without the slip in a smaller converter but if they are indeed 9.5 inches in size? that sounds about right.

[jamesmost]

its billet and different hardened steels.....

got it back, the runout was offff as trans. shop suggested.

they put in a new hub updated internals and checked for runout 2X...

no charge, but ofcourse would not contribute to the damage it caused..

at trans shop today getting re installedJames

[elwesso]

after hearing all this BS im pretty sure that if a good converter guy who did racing converters would do much better work that precision... Then again, in converter land $800 isnt really a lot of money...

[jamesmost]

after hearing all this BS im pretty sure that if a good converter guy who did racing converters would do much better work that precision... Then again, in converter land $800 isnt really a lot of money...

no one else in my experience will do it.... not just bent finsdam shame they r a bit retarded

[Rex]

Here's some info that might be worthwhilehttp://forums.nicoclub.com/zerothread?id=101687

[elwesso]

thanks for digging that up Keith... Always a great read.

[jamesmost]

Updated pRECISION tc INSTALLED Got car back todayand it is sooo sweetMad torque at a tap of the pedalwill rack up some highway miles 2 morroJames

[jamesmost]

Put on a few hundred highway miles....

better then the older precision tc.

really feels amazing. the torque multiplier is immense

car just shreds..............

Need 255 in the rears.................James