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Andrews 86 langley turbo **AWD PROJECT***

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Insane_N12
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Post by Insane_N12 »

haha it wouldnt be fun if things didnt blow up!
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JETETT
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Post by JETETT »

ok finished work at 4 this arvo and got stuck into the box, in a space of three hours i got the box out and the spare in

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broken box, housing is cracked some where
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this is my good box out of my silver ET, the bugger survived after i broke 2 outer cv's at once on my sliver et
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i dont run a front engine mount
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beefed up rear mount
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All done now it need some gear box oil :)
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JETETT
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Post by JETETT »

tassuperkart wrote:
JETETT wrote: some goddies arrived today a swift gti twin cam head :D and a 4age twin cam head looking at possible modification and possible mating of these heads onto the e15 block.
cheers
Sadly they dont. not even close. Its all been tried.
L8r
E
Hey E... i havent even bothered to look, i got the heads for free any case, i have a mate that works at pick a part, but i dont think im going to even bother with it to be honest too much for me atm, if its been tryed before and no go i wont even give it a thought, cheers for the heads up...

cheers
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JETETT
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Post by JETETT »

looking at my dyno papers and looking at the torque and did a unit conversion, around 890LBS converted to N.M =1206nm of torque :? does that sound correct guys?? its torque that kills gearboxes not HP

cheers
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tassuperkart
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Post by tassuperkart »

Horsepower is really just a mathematical equasiuon of torque and RPM so neither one really makes a huge differen on its very own.

What kills the transmissions is not any amount of power/torque or whatever that your engine can produce but more the repeated extreme impact loads from the likes of flat-changing with no engine cut, clutch-kicks, fish-hooking and in particular, front wheel tramping and big launches with grippy tyres AND using a grippy and savage button clutch.

Causes all sorts of horrors including gearcase flexing and bending of the gear shafts with reduced depth of mesh of the gearteeth and like any repeated abuse, metal fatigue and ultimate failure is the eventual result.

If it was the straightcut box, then the gearteeth are actually weaker than stock spur cut teeth as the transmission load is transmitted purely by the cross sectional thickness of the teeth themselves whereas a spur cut geartooth is actually thicker in section to to its angled nature altho the contact patch is smaller.
Straightcut gearsets are not always what they seem to be. The do however eliminate any end (thrust) loading of the gear shafts!!!

Unless you are prone to the nefarious driving practises as above then I suspect you were just unlucky.

One of the best ways to destroy a transmission and/or axles is to be spinning at high speed from a dirt surface to a grippy pavement as in a big takeoff from a dirt verge and suddenly up onto the pavement. The sudden impact loadings thru the transmission are enough to rip engine mounts clean off the engine/chassis and smash axles/CV's/driveshafts and Uni (Cardan) joints

L8r
E
Forcd4 wrote:Oh fuk no dude it's you a again, the oracle.
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JETETT
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Post by JETETT »

none of the above E, was just a easy take off in first off the lights eased into second then foot down and full noise (screamer pipe between buildings is awsome) and bang she went, no clutch kicking which i like to do, just pedal straight to the floor...

now with the box apart i was lead to believe by previous owner that it was straight cut, its not the case in this matter, altho it has a different straight cut crown wheel how ever compared to the helical crown :? :?

cheers
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Damo
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Post by Damo »

JETETT wrote:looking at my dyno papers and looking at the torque and did a unit conversion, around 890LBS converted to N.M =1206nm of torque :? does that sound correct guys?? its torque that kills gearboxes not HP

cheers
Just to add to what E had said down the page, I found that my boxes weakest link in my combo was where the wheels stopped spinning and unloading the box. And that used to be in 3rd gear in mine. Twice, I gently took off from standstill in first through second, plonked it into 3 at less than 2000rpm, brought it upto full boost and that was where it was making max torque without shedding any through wheelspin. Then BANG!

As for the amount of torque the engine is making, you need to do a little reverse math. The only two things the dyno knows is rpm and torque. The HP figures that the dyno spits out are a calculation in the software. Your even better off, as yo have the tractive effort marked out.
If the combo is making 900ft/lbs at the rollers you need to take into account the gearing you are using. Final drive 3.75, 3rd gear 1.26 (I'm guessing.) 900/3.75/1.26= 190ft/lbs Then tyre radius, which is very close to 1ft, approx 300-320mm, so this figure may be a couple of % either way.
Then I would add about 10% drivetrain loss. So the box would be copping near on 270-300Nm. Thats twice the factory twist!



Damo
Do humanity a favor, use your brain and fight the forces of WOO WOO!


http://www.youtube.com/watch?v=G1mrbxhWU5Y
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JETETT
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Post by JETETT »

Damo wrote: I gently took off from standstill in first through second, plonked it into 3 at less than 2000rpm, brought it upto full boost and that was where it was making max torque without shedding any through wheelspin. Then BANG!Damo
exactly what happend to me but in second gear
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as for calculating torque and gear ratios i havent a clue lol but below are the differences between my torque box compared to a standard box which i can reach higher speeds in each gear

the box i broke
input gear (pinion) 15 teeth and output gear (crown) 52 teeth
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standard box input gear (pinion ) 20 teeth and output gear (crown) 71 teeth
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Damo
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Post by Damo »

52 teeth! How strange. Where the hell, and why the fuck would 'they' have done that.

Either way that still works out to be 3.46 which isn't too far away from the factory 3.55-3.79. Mind you, with a lower final drive it would make the situation slightly worse, not better.

The best cheap solution is the 4.11 final drive from the N13.


Just check out what has actually broken first. Mine always seemed to destroy the synchro hub for 3rd and 4th. This would send bits through the box and everything would break.


Damo
Do humanity a favor, use your brain and fight the forces of WOO WOO!


http://www.youtube.com/watch?v=G1mrbxhWU5Y
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tassuperkart
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Post by tassuperkart »

No not necessarily Damo.
The diff has a much bigger tooth profile that stock, which is usual given that the straight cut tooth profile is weaker for the same pitch and so the tooth count will be naturally different on both gears.
It would depend on the tooth count on the input gear see? It will be different by a similar percentage to the crown wheel otherwise depth of mesh problems appear.
No in a million years would the ratio be so fast such as 3.4.

Im curious to see what the builder did with regards to the input gear. Given the stock input gear is machined directly onto the shaft, is it a welded gear over the stock machined shaft or a complete fabricated shaft?

Andrew
Im not so much saying the failure was a RESULT of a bad thing but the damage has already been done previously and basically, you had a failure waiting to happen.

L8r
E
Forcd4 wrote:Oh fuk no dude it's you a again, the oracle.
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Damo
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Post by Damo »

tassuperkart wrote:No not necessarily Damo.
The diff has a much bigger tooth profile that stock, which is usual given that the straight cut tooth profile is weaker for the same pitch and so the tooth count will be naturally different on both gears.
It would depend on the tooth count on the input gear see? It will be different by a similar percentage to the crown wheel otherwise depth of mesh problems appear.
No in a million years would the ratio be so fast such as 3.4.

Im curious to see what the builder did with regards to the input gear. Given the stock input gear is machined directly onto the shaft, is it a welded gear over the stock machined shaft or a complete fabricated shaft?

Andrew
Im not so much saying the failure was a RESULT of a bad thing but the damage has already been done previously and basically, you had a failure waiting to happen.

L8r
E
Just working with the quoted figures. 52 on the crown and 15 on the main gives a 3.46 final drive which makes the problem of loading the main shaft worse.
Do humanity a favor, use your brain and fight the forces of WOO WOO!


http://www.youtube.com/watch?v=G1mrbxhWU5Y
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tassuperkart
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Post by tassuperkart »

My bad damo. Ill take that back. I didnt see the pinion count.
If its 3.4 , what a POS! Need 10" wheels to do any good!!!

L8r
E
Forcd4 wrote:Oh fuk no dude it's you a again, the oracle.
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JETETT
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Post by JETETT »

cheers for your input E & D :D the box was a fair bit on the WTF side after not driving an ET for 3years, first and second gears were fukd changing into 3rd before or just after 100kph and remembering that i used to push almost 120 - 130kph in second in my silver et... would this box affect total power i made??

so with the broken box all calculated with gear ratios from the tomie website (http://www.tomeiusa.com/2010top/index.html) scroll down the left side for gear ratios using microsoft excel and looking at my dyno print out. in third gear at 5500rpm at 140kph on this pos box

compared to the standard final gear ratio its making 140kph at 6000rpm hp???

it gets to 140kph quicker in the rev range compared to the standard ratio

3.4 ratio
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standard ratio
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stupid thing is tho, i cant believe i threw out spare n13 vlsd box that came with the car :oops: :oops:
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Damo
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Post by Damo »

JETETT wrote:cheers for your input E & D :D the box was a fair bit on the WTF side after not driving an ET for 3years, first and second gears were fukd changing into 3rd before or just after 100kph and remembering that i used to push almost 120 - 130kph in second in my silver et... would this box affect total power i made??

so with the broken box all calculated with gear ratios from the tomie website (http://www.tomeiusa.com/2010top/index.html) scroll down the left side for gear ratios using microsoft excel and looking at my dyno print out. in third gear at 5500rpm at 140kph on this pos box

compared to the standard final gear ratio its making 140kph at 6000rpm hp???

it gets to 140kph quicker in the rev range compared to the standard ratio

3.4 ratio
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standard ratio
Image

stupid thing is tho, i cant believe i threw out spare n13 vlsd box that came with the car :oops: :oops:
Its the same old 'same old', yes it would probably make a difference in the final figure the dyno gives you, but in all honesty the figures don't mean dick. There are sooooooo many variables that need to be put into the same dyno to get it to read the same value on the same cars on two different days even before you try and compare two different figures from two different dynos.
The best approximate of power, is fuel consumed per hour or duty cycle of known injectors. 1ltr per min of non ethanol pump fuel is good for 120-140kw at the engine.
Dynos are great for fine tuning setups, and comparing mods on the car for changes in the curve. And at the outside, comparing from engine to engine, cam and turbo behavior. Thats pretty much it.

Looking at your dyno graph (and mine also) it shows that the peak torque (which is basically max boost) doesn't happen till after 1/2 engine revs, which on the surface doesn't mean much (as guys are usually looking at peak power figures), but on the road you need to have the engine spinning up there to get any meaningful acceleration, and when it does happen up there, the engine torque changes so rapidly that it become extreamly hard to control engine output. Instead of the throttle position controlling power, it is dictated by boost pressure which is changing with engine revs.
If you know what you are looking at, the shape of the dyno curve speaks volumes of what the engine is doing.


Damo




Damo
Do humanity a favor, use your brain and fight the forces of WOO WOO!


http://www.youtube.com/watch?v=G1mrbxhWU5Y
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JETETT
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Post by JETETT »

Ah i miss my old ET lol, it will be remembered in my purple one tho half the parts from the silver one made it to the purple one...

when i first got it

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to what i done to it

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whats been transferred to my purple one, wheels, rear brakes, front lights and indicators, front bumper, front skirt, all the door cards window winders and windows inc rear window, door locks inc boot lock had to transfer the internal guts of the lock, front and rear seats, holy shit handles, dash, center console, adjustable tilt steering, steering wheel, hand brake system, gearbox, dash and cluster wiring harness, ET aerial... Number plate will make its way on there soon :)

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