Stagea Transmission Options

[Lone]

Well after some slow times at willowbank this weekend (best 15.1 at 90mph) I am wanting to start looking at upgrade options in the transmission in the car before going for some more power (just panel filter, 10psi and catback 3" exhaust at the moment) because I think that is one spot that I am definatly loosing some of my times in as it seems to be impossbile to get a good launch.

I was launching having the car in 'power mode' and had my left foot on the brake and the other on the accelator to let it build up revs a bit getting up to about 2300rpm at the best but still on getting 2.3 60 foot times which im certain I should be able to improve in having a 4wd system. I also have some other little excuses like a slight miss which Ill aim to fix this week as well.

The main thing im asking is what options are there for upgrading the standard transmission (auto) to start getting better launches/times on the 1/4 mile?

Obviosuly a manual conversion would be the best but im guessing adding in all the factors like price of box and clutch it would easily hit over $3000?

But what options are there for the auto and is it worth my time/money tryign for power with it and are they all that strong?

[Jay95R33]

Installing a shift kit is an option, but I don't think that will reduce your 60 foot times. To get your 60 foot times down you may need a higher RPM stall converter.

Nitrous on launch would help But I know that's not an option.

But seriously, have a look at this thread - http://www.skylinesaustralia.com/forums/sh...ead.php?t=61862

They are thinking about doing a group buy for some shift kits for the auto's. May be a good start.

J

[Sydneykid]

High rpm stall converter and an upgraded valve body. Do you have a big transmission cooler? When they get hot they slip more, that makes the oil even hotter and they slip even more.

What boost are you seeing at the 2,300 rpm launch?

[Lone]

Jay95R33: looks very interesting those shift kits, what exact advantages will you be able to achieve with them? I havent played at all with autos before, its a new world to me

Sydneykid: Only what I presume to be the standard cooler in the front, it might be slippage when it changes gears come to think of it as there is a weird dull high rev sound in between gears... As for boost levels from memory it wasn't too much at all, I do know it was spooling though.

[Jay95R33]

When it comes to Auto's I'm on a pretty steep learning curve myself

But from what I've found out, the shift kits speed up the gear changes. Auto's are the opposite to manuals when it comes to changing gears. With an auto, apparently faster is better for the life of them. Faster = less slip = good.

I've never driven a car with one, just going on what I've read etc..

J

[BoyWhoCriedWolf]

Still 15.1 is not a bad time for a fat wagon, try getting a stock SS commode down the line in that time. Even better considering that it is stock standard. Well done Lone.

Ken

[Sydneykid]

Jay95R33: looks very interesting those shift kits, what exact advantages will you be able to achieve with them? I havent played at all with autos before, its a new world to me

Sydneykid: Only what I presume to be the standard cooler in the front, it might be slippage when it changes gears come to think of it as there is a weird dull high rev sound in between gears... As for boost levels from memory it wasn't too much at all, I do know it was spooling though.

I strongly suggest an upgraded transmission cooler, I posted up a thread on my installation. Have a look there.

Our Stagea gets to 0.3 bar at 2,250 rpm when held against the foot brake. It then starts to wheelspin, just the back wheels only. The front brakes, being much bigger, can hold the front wheels and stop them from turning. Ours is currently stock standard, exhaust, intercooler, fuel, even the air filter is standard so it only gets ot 0.4 bar max. I imagine with only the exhaust upgraded you could get even more boost holding against the torque converter.

As soon as I take my left foot off the brake and flatten the accelerator, boost jumps to 0.4 bar. So a higher RPM stall converter is not on my list at the moment, more boost will do fine.

As RBNT suggested, Stageas are heavy (ours is 1,658 kgs with zero fuel), that's 140 kgs more than the GTR. So the inertia is always going to make them a bit tardy off the line.

Hope that makes sense:cheers:

[Terminal]

Mines been boosted to 10psi, and when i try the left foot braking thing it creeps forward over about 2000rpm. i try it at lights and so on to practice my launches, and the brakes just aren't strong enough to hold the car back. i'm thinking about an R34 brake upgrade in the near future for that reason

[Abo Bob]

That might be more related to where your torque converter is rated to. I can't get over 2000rpm from mine without wheelspin or moving forwards.

[Jay95R33]

How long do you guys stall it up for before letting it go? Is it bad for the transmission to be stalled up all the time ?

I'm always scared that I'll hear a big bang

[Abo Bob]

I've been down the strip about 30 times - all on one day - with no dramas. Apart from that I've only done it about 5 other times.

I can't imagine what would blow. I think your brakes would give and you would smoke them. All speculation on my part though.

[Sydneykid]

That might be more related to where your torque converter is rated to.  I can't get over 2000rpm from mine without wheelspin or moving forwards.

The Stagea weight and traction advantage at work. Have you tried both the handbrake and the foot brake? I am hoping that they can hold 200 4wkw, with the transmission in 4wd of course.

PS; the SA guys are organising a Group Buy on MV Automatics valve body upgrades, they should be around $300 exchange. I've put my name down for one. :aroused:

[Terminal]

Is the valve body upgrade a general Nissan valve set, or is it designed specifically for the stagea's awd auto box?

[Lone]

Thanks RBNT

Im getting keen on those upgrade kit group buys, im also really keen to work out the best way to launch this thing, its such a waste of the 4wd system on the 1/4 mile track not being able to launch it hard

Out of interest when racing straight line what gear does everyone here use? I have found just keeping it in drive from start to finish the quickest, if I try and manually shift going anywhere from 60-100 if I switch from 2 to D the car instantly pulls harder... The car is quite quick from rolling at 100 but down low its got nothing

Also would have the 4wd button on make much difference on both launch and times?

[Sydneykid]

Hi Lone, what sort of 4wkw does your Stagea have? Even in the rain I can't get my standard power one to wheelspin much at all. Just a little rear wheel rotation then the front kicks in and it's offffffffff. I think locking it in 4wd would only help if you had too much rear wheelspin before the fronts start taking some torque. I figure when I get to my power target of 200 4wkw, the 4wd will help a lot.

The car is quite quick from rolling at 100 but down low its got nothing

That's weight, once you get over 80 kph, weight becomes less of an issue. Aerodynamic load takes over about 130 kph, so you have this bit between 80 and 130 where they feel really quick. This speed range also matches the engine's power band in third, so that helps as well.

Tomorrow I am going to fit the Jaycar stuff and just turn the boost up to 0.7 bar. But I will leave the fuel alone until I can get some time on the 4wd dyno next week. I like these mid week public holidays:cheers:

[Lone]

I love these mid week holidays as well, great chance to catchup on stuff

I made 140 4wkw on a dyno up here, reputable dyno, it was in the middle of the day (heat) and elevation of around 800m.. Such a big drivetrain loss

Some very good points there made about the weight factor, shame you cant legally do rolling starts

[Sydneykid]

I love these mid week holidays as well, great chance to catchup on stuff

I made 140 4wkw on a dyno up here, reputable dyno, it was in the middle of the day (heat) and elevation of around 800m.. Such a big drivetrain loss

Some very good points there made about the weight factor, shame you cant legally do rolling starts

The 140 4wkw means around 220 kw at the engine. GTR's loose around 70 to 80 kw through the drive train in 4wd. Maybe another 10 kw for the auto. That's ~50 kw more than a standard S1. Which is pretty good for a panel filter, boost up to 10 psi and cat back exhaust. I reckon ours (standard as it is) would be lucky to make 100 4wkw. That's why I reckon 200 4wkw would be nice, the trick is getting the power everywhere, I don't want to loose any power at any rpm points. It has to have more power everywhere:cheers:

[Jay95R33]

Just on the topic of transmissions, I found info on how to get the auto transmission into diag mode.

Here's the link;

http://www.skylinesaustralia.com/forums/sh...755#post1179755

[PranK]

so what does the shift kit do? does it allow you to shift ? or does it speed up the shifting?

i dont get it.

[Lone]

Out of curiosty SK what do you plan for any transmission fmods for your stagea to help improve launches?

As you know I dont know too much about autos but is a trans brake a feasable option for the stagea auto transmission?

Im really wanting to get something to fix up the slow launches ie. higher revs on launch but still be fine to drive day to day (can increase torque convertor revs for around $380 but it will be llike that permantly). Damn you nissan, why curse the rs four series one to autos!!