Author Topic: Beefing up your auto transmission (HNU13) (Read 5479 times)

fez200 · « **on:** Sep 13, 2006, 09:35AM »

I have a U13 attesa and I know a lot of people have done conversions from auto to manual. the cost being around the $3000 mark.

but i have also heard that making your auto stronger or making shifts quicker will outlast and possibly be as good as a manual box plus have the added advantage of returning good fuel economy.

has anyone done a complete breakdown on the costs and parts involved with doing this?
eg.
shift kit $$$
trans cooler $$$
stall converter $$$
approx labour $$$

nxka24de · « **Reply #1 on:** Sep 13, 2006, 03:33PM »

i have a mate who's done this to his soarer and i gotta say, while its cool to have vrrrooom - K CHUNK - vrrrooom.. it kills your diff. he's been through two in 3yrs and it makes it somewhat annoying to drive in traffic cos each time your box decides to shift K CHUNK.

does do wonders at the drag strip tho...

Wolf In Sheep’s Clothing · « **Reply #2 on:** Sep 13, 2006, 03:45PM »

I personally wouldn't try it on a U13 box as there not very strong your likely to kill the box, tranny cooler could be a good idea for a mod tho.

Whats your goals for the car?

Jono · « **Reply #3 on:** Sep 13, 2006, 10:04PM »

Putting a 'shift kit' in your transmission to make it shift quicker makes your times quicker at the drag strip, but it decreases the life of your transmission. It also makes the car less comfortable to drive and puts more strain on all the components in the box.

Trans coolers are always good, and high-stall converters help with your launches if you don't mind a bit higher fuel consumption when cruising.

fez200 · « **Reply #4 on:** Sep 13, 2006, 11:27PM »

my aim is to get a better launch.it has no go till about 3500rpm. i guess thats due to turbo lag mainly.

i killed my last auto with a few 3000rpm stall launches...wont make that mistake again.

your right with the U13 box being weak, maybe i bite the bullet and go the way of a manual trans, and probably get it built tough.

Jono · « **Reply #5 on:** Sep 13, 2006, 11:31PM »

How long were you holding it stalled up to 3000rpm?

Stalling up transmissions generates alot of heat which can kill them extremely quickly.

fez200 · « **Reply #6 on:** Sep 14, 2006, 03:27PM »

not long about 3-4 seconds. but that was enough to stuff the last one.

but i dont do it know....if i ever do its for only like 1 sec.

Jono · « **Reply #7 on:** Sep 14, 2006, 06:52PM »

Yeah I'd only stall up for 1 second maximum.

When you've got it stalled up all the power the engine is making gets turned into heat in the torque converter... say about 50kw of heat, that'd be like having 25 large bar heaters in your gearbox. i.e. very freakin hot.

3391 · « **Reply #8 on:** Sep 17, 2006, 11:58AM »

what you need to do is have the valve body in the tranny upgraded as well as a torque converter upgrade. with this it will be able to handle boosted engines. we have quite a few turboed auto U13 over here with no tranny problems.

fez200 · « **Reply #9 on:** Sep 19, 2006, 09:11AM »

i was offered a U13 Attesa 5 speed manual gearbox on the weekend for $700 complete.

i wasnt sure that was a good price. if it is, is there anything i have to do before i get it put it in..
ie get it checked out by a gearbox specialist to see if its ok. im not sure what can go wrong with the manuals.

if anyone has done a conversion before did they run into any problems with it.??

Wolf In Sheep’s Clothing · « **Reply #10 on:** Sep 19, 2006, 09:47AM »

$700 for a manual is cheep I payed $1100 a few weeks back for one.

Auto to manual conversion you will need a few things. Clutch pedal, clutch master and slave cylinders, clutch, shifter, surround for the shifter etc. Even then the manual isn't the strongest thing in the world. If you want to make a lot of power with the u13 you should think about a PAR or PPG forged gearset and some strengthening to the casing.

So gearbox for $700 then you have to pay for the other bits and pieces some of which will be very hard to find, then you have labour and the option of a forged gearset and strengthened casing. If you went all out you are looking at a lot of hard earned cash. Forged gearset is roughly $5000 alone.

http://www.antrx.com/smf/index.php?topic=10941.0

Not a U13 but it will give you an idea of what has to be done.

fez200 · « **Reply #11 on:** Sep 19, 2006, 05:13PM »

seems like im stuck between a rock and a hard place here.

ive always been told to convert it to a manual. when the last auto box died and my newly installed box flaring between gears sometimes, i dont know what to do.

i was just going to get this manual box checked,serviced and put in say a heavy duty clutch. and drive it.

im not going to use it at the drags or nothing and i wont be doing 5000rpm full dump starts either.. so you would think it might hold up better than an auto in some respects.

Wolf In Sheep’s Clothing · « **Reply #12 on:** Sep 20, 2006, 09:57AM »

It will defiantly hold up better than the auto if you treat it right, use some shockproof gear oil, don't dump the clutch and get a heavy duty but not too heavy duty clutch. I have a Xtreme heavy duty clutch in my manual box and thats meant to be the perfect clutch for the box, according to Croydon Racing Developments who know there stuff. Don't get a brass button clutch or twin plate clutch if you want the box to live.

http://www.xtremeclutch.com.au/products.htm#

Reference No. KNI24003

Clutch I have in my Attesa.

fez200 · « **Reply #13 on:** Sep 20, 2006, 10:17AM »

well i made up my mind ad getting the manual conversion.

what made up my mind was the fact that my auto shit itself last night and wouldnt find reverse and took off in 3rd. then it came good again.
the same sorta thing that happened before, and i only put this box in like 2 months ago.

the guy is giving me the gearbox, pedals, shifter/surrounds, harness, master cylinder for $700. im not sure what else is required. so if anyone knows that would be great. will the conversion be a straight swap? ie will there be too much work too do, apart from having to drop the engine and fit the pedals.

Budgie · « **Reply #14 on:** Sep 20, 2006, 11:01AM »

This is strange, almost the exact scenario I went through.

Killed my first auto by stalling it upto 3000rpm then launching. Although mine suffered ALOT of these launches and lasted a good 8 months of abuse before shearing something inside the auto. Interestingly I am about to take the trailer over to my grandmas place to remove the auto from her backyard, where it has been sitting for months (minus the transfer case

)

My second auto was fitted. Had no big dramas with this one as it only had 56,000km on the box. Only issue was it would hold first for AGES when cold (slightly blocked governor). After it was at operating temp the box was perfect.

I finally got sick of the auto and the extreme slowness off the line, sourced a complete manual RNU12 ATTESA and performed a manual conversion. The parts/processes involved in doing the conversion on a HNU13 would be much the same. Refer to this thread for more detailed info - http://www.antrx.com/smf/index.php?topic=10941.0

My conversion went very smoothly, because I had EVERY part needed on hand. Only had one drama, with a faulty master cylinder. $700 for all components needed is a good price. All parts minus clutch/new master cylinder/throw out bearing cost me $700 or so dollars as well.

phreeky · « **Reply #15 on:** Sep 20, 2006, 03:00PM »

Quote from: fez200 on Sep 20, 2006, 10:17AM

the guy is giving me the gearbox, pedals, shifter/surrounds, harness, master cylinder for $700. im not sure what else is required. so if anyone knows that would be great. will the conversion be a straight swap? ie will there be too much work too do, apart from having to drop the engine and fit the pedals.

thoughts:
- need slave cylinder
- need clutch lines, has metal + hose sections (could get a new one made up i suppose)
- you wont need the harness
- need a flywheel
- need a clutch
- are the gearbox mounts the same? (FAST database could answer they quickly)
- maybe appropriate gearbox bolts if the auto ones are different
- on the manual box, grab the input shaft and wiggle - it should have absolutely zero play/movement. turn by hand, it should not be overly hard to turn (either in or out of gear) and should be quiet (they'll most likely be a slight audible noise).
- undo the filler and drain plugs on the gearbox and transfer case before doing the conversion, to ensure they actually undo
- consider buying a brand new clutch fork, and make sure you're getting a good quality throw out bearing
- replace all the coolant hoses on the back of the engine while its out (u can buy a kit from gmc on pulsar forums i think - www.gccorp.com.au)

shouldn't be too hard, i suppose you'll have a bunch of auto rubbish sitting on the garage floor afterwards. that's all i can think of at the moment.

Budgie · « **Reply #16 on:** Sep 20, 2006, 03:49PM »

A bit more phreeky/fez200:

- Some of the auto mounts ARE differant (I sound very sure of this as i'm certain the U13's are very similar in this regard to the U12's)

--- Front torque mount was the same on my CA (auto & man)
--- Rear torque mount was differant, but only the bracket that bolts to the top of the gearbox/transfer case. It had a slight downward kick on one side (1cm or so).
The dog-bone mount itself was exactly the same.
--- Front gearbox mount and bracket (under battery on U12's) I sourced this mount and bracket from a HNU12 as it was totally differant on a manual. Its also differant to the
FWD's as it has an extra bit of bracing that bolts to the gearbox in another place lower down.
--- Rear gearbox mount itself was the same and where it bolts to the chassis, but the ' L ' shaped peice that it bolts to, which then bolted to the manual box was differant.

- You will need linkages from an AWD HNU13, but shifter/cup/knob from a FWD should work fine (did on my U12).
- If you don't have a manual brake pedal, just trim your auto pedal down and get a rubber cover from another U13/U12 clutch pedal and put it over the cut brake pedal (clutch/brake pedal rubber pads are the same on the U12's anyway).

Phreeky and I have preached the 'change coolant hoses' line many times now, its a VERY good idea to do this when the engine is out of the car! It will save you many hassles later on.

dave-trx · « **Reply #17 on:** Sep 21, 2006, 07:42PM »

The hoses under the intake manifold are a bitch to do with the engine in the car, I did mine in my TRX, 1 of the worst jobs I have come across.

Counterpunch · « **Reply #18 on:** Sep 27, 2006, 06:36PM »

This may be a bit late but I had the auto in my U13 Attesa rebuilt with strengthened parts specifically for drag racing by the previous owner. It cost $4000 to get 3000 stall converter and included all the parts and labour to remove and refit engine and gearbox. About $2000 was labour and the remainder was parts. End result is it takes off from the lights very quick. And when it comes to shifting gears, it will shift faster than any manual driver. I've beaten Skylines, WRX's and various other cars because of this. Generally not at first but through gear changes I catch up and overtake them by third gear. I've never had any problems since. However the comfort is not as great as stock. You do notice the clunk as it changes gears even when you don't drive hard. But I'm happy to accept that for increased performance.

fez200 · « **Reply #19 on:** Sep 28, 2006, 11:00AM »

Yeah i had heard that before. i had a shift kit and stallly put in my HSV. was excellent for drags, chirped into 3rd, but you suffered in comfort when cruising, which is what i think the auto in the Bluebirds were made for.

I cant wait to get the manual now...!! im getting the clutch that wolf recommended.

but the clutch place im buying it from said they would increase the clamp pressure on it for an extra $30. worth it?

they were going to make me a custom performance clutch for $600, ceramic plate with nissan patrol centre? etc.., he reckons it would be damn strong.

Wolf In Sheep’s Clothing · « **Reply #20 on:** Sep 28, 2006, 11:05AM »

Its proberly not worth increasing the clamping pressure, safer to have a clutch that is more likely to slip, think of it as cheep gearbox insurance. The clutch I have should handel more than 180awkw without slipping.

Marty · « **Reply #21 on:** Sep 28, 2006, 07:44PM »

Quote from: Jono on Sep 13, 2006, 10:04PM

Putting a 'shift kit' in your transmission to make it shift quicker makes your times quicker at the drag strip, but it decreases the life of your transmission.

I've heard the complete opposite about this, That making the shifts quicker increase the life as its spending less time slipping between gears.

I'm also getting my auto rebuilt. instead of going the manual way. hopefully within the next 2 weeks.

Jono · « **Reply #22 on:** Sep 28, 2006, 08:19PM »

It actually slips just as much, just at a higher pressure so when one clutch overpowers the other it jerks the car forward instead of changing gears smoothly.

It is quicker on the track though.

Marty · « **Reply #23 on:** Oct 28, 2006, 12:00PM »

My car is currently at the mechanics (Baileys Autos in Perth) Known for there performance gearbox building over here, But
He cant find anything at all to strengthen the box, he can find all the generic replacement parts but cant get a shift kit or any heavy duty parts as counterpunch mentioned.
I think he broke an engine mount too, grrr, so can someone PM me the places they got theres done so I can give them a call and find out what they used, cheers
Anyone selling any engine mounts too

apparently 3 weeks from japan what the

Counterpunch · « **Reply #24 on:** Oct 30, 2006, 05:24PM »

Which engine mounts are you after. I probably have some that you are after. How exaclty do you break a mount? Unless of course he meant the rubber? There's a place here which rubber fills them for about $120. Only worth it for the main engine and gearbox mounts which cost over $200 and take 3 weeks to order. The front and rear ones you can buy at auto shops for about $50 as they are the same as the pulsars.

Marty · « **Reply #25 on:** Oct 30, 2006, 06:27PM »

ah ok then, yeh not sure which one he meant,
anyway he's doing a valve job thingo and stall convertor and replacing all the bits inside that are fubared, so hopefully it should be seeing the drag strip next wednesday, he still couldnt beef up any of the internals so to speak, so I guess I'll be keeping this car fairly normal in terms of power figures.