Jump to content
SAU Community

Recommended Posts

hey guys,

got a rb20det in my vl commodore, standard engine, do have the 33 gtr cooler and a blow of valve and a brass button clutch, does 14.0 down the quarter with more to come but, i need advice and well u guys are the people to ask....................................... my gearbox is just about had it, and i know they aren't the best gearboxes in the world and are renowned for breaking, my dilema is weather i should

1. get a replacement and hope it doesn't turn out like the one i got now, bout $ 550 to $600 or..........

2. get the gearbox i already have rebuilt which would mean it would be stronger wouldn't it? ( and i have been quoted $880) and me and my friend are doing all the labour,

.................................HELP........................ :boinkcar:

Link to comment
https://www.sau.com.au/forums/topic/79037-toldja-and-his-gearbox-dilema/
Share on other sites

what about put a r33 gearbox behind it?

they are basically a 2wd GTR box and alot of high powered r32s do the conversion.

and bout triple the price aren't they, got quoted almost 2000 which i just don't haveat the moment, 880 i can just scronge up but 2000 is just way out of my league for a gearbox, i would love one cause everybody i have talked to bout them say they are almost bulletproof?

Hi Bruce!

Like the convo we had the toher day, if the guy rebuilding the box claims it will be a strong as an RB25 box, go for it! Its just buyin a 25 box but a whole cheaper. If i win the lotto ill buy you a 25 box mate! But i cant see that happening!! :P

Your call chief!

A rebuilt RB20 box will not be as strong as an rb25 box, I dont care who you are, the RB25 box is a LOT bigger.

But it would be $2k drive in drive out kinda thing dude, if your doing it yourself it wouldnt be that bad.

But the other thought would be go for another rb20 box, but get a less harsh clutch, ie NOT a button clutch of any sort, I can tell you now that wouldnt be helping the life of it. Its probably whats hurt mine.

Other option would be a VL turbo gearbox, same as an Rb25 box just they dont have dual syncros, bit stronger than rb20 boxes apparently, somewhere in the middle.

A rebuilt RB20 box will not be as strong as an rb25 box, I dont care who you are, the RB25 box is a LOT bigger.

But it would be $2k drive in drive out kinda thing dude, if your doing it yourself it wouldnt be that bad.

But the other thought would be go for another rb20 box, but get a less harsh clutch, ie NOT a button clutch of any sort, I can tell you now that wouldnt be helping the life of it.  Its probably whats hurt mine.

Other option would be a VL turbo gearbox, same as an Rb25 box just they dont have dual syncros, bit stronger than rb20 boxes apparently, somewhere in the middle.

Thats what i thought as well, i thought it was a bit suss that a gearbox guy would say that, thats why i directed old mate toldja to here for a few Q and A's. If what that guy said was true i wouldnt be think of a 25box for my 32, id just get it rebuilt, under 1g? Thast awesome but i guess htere are a few holes in his story.

Bruce mabye you should go all out and get one of those HKS 6 speed dog boxes? :) Now id like to see that! :crazy:

Oh, the only thing I forgot to say is... If you get your RB20box rebuilt, it does give you peace of mind. Its the only thing Im REALLY worried about by putting the RB25 box in mine, basically, what if the box is stuffed... then I have to spend a further $1500 to rebuild it.

But hey, its a car dude, expect to just throw away money.

I wolldnt go another rb20 box if i was going to be going to the drags, racing or drift.

I broke 2 rb20 boxes within a year in my cefiro. and i didnt have a stupid ammount of power either. 165rwkw when i got the car and 195rwkw when i sold it.

but i did have a brass button clutch.

both times it was the input shaft that went. First time it stripped and second time it actually broke!

you can get an rb25 box for $1100 to $1500 if u look around and it only takes a few hours to shap it yourself if you have stands or ramps.

hmmmmm. well then , money is the problem but i suppose if i baby it some more and jsut save up some cash i might get the 25 box thats what i want, the guy that told me that it was ging to be alot stronger was a guy from gearbox express in like minto in sydney, these opinions are great, keep em coming...... does the 25 gearbox go straight onto the 20 without any probs at all? is there any modification at all?

rb30 - single syncro per gear, same casing as rb20 box same gearsets.

rb20det dual syncro per gear same gear set as above same strength

rb25. same gear ratios as rb20 but bigger shafts, stronger splines and carrier gears and double sincros. bigger casing and stronger yoke.

rb30et. same as above but only single syncros and less ribbing on the casing (i think its 5 ribs insted of 7)

I have also been told the rb30et boxes come in 2 different ratios.

If you look in the forsale section here from time to tome you will find a wrecked r33 with reasonable k's and you will be able to get a box for $1100.

I have seen them from $900 but not often that cheap.

these boxes are very difficult to brake so if you get one from a stock car it should be in good condition.

:]

In regards to bolting it up tho...

You will need a new cross member, and need to get a custom tailshaft made up. Speedo cable I would guess would be manual on your car not electronic, so that needs to be fixed up too, I belive it was GTR or nivara you could use. Thats using a RB25 box.

sounds like quite a few dollars daveo, hmmmmmm, the box i have now has lasted two years, so i don't lknow......................aaarrrggggggghhhhhhh

I'll tell you in a few weeks exact cost ;)

Personally I think if you change your clutch you shouldnt keep breaking them. Id do the same, but I cant be faged and I have a set out plan on whats going to happen with my car over the comming years. So for me the box will be a concern down the track.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • @Haggerty this is your red flag. In MAP based ECU's the Manifold pressure X RPM calculation is how the engine knows it is actually...running/going through ANY load. You are confusing the term 'base map' with your base VE/Fuel table. When most people say 'base map' they mean the stock entire tune shipped with the ECU, hopefully aimed at a specific car/setup to use as a base for beginning to tune your specific car. Haltech has a lot of documentation (or at least they used to, I expect it to be better now). Read it voraciously.
    • I saw you mention this earlier and it raised a red flag, but I couldn't believe it was real. Yes, the vacuum signal should vary. It is the one and only load signal from the engine to the ECU, and it MUST vary. It is either not connected or is badly f**ked up in some way.
    • @Haggerty you still haven't answered my question.  Many things you are saying do not make sense for someone who can tune, yet I would not expect someone who cannot tune to be playing with the things in the ECU that you are.  This process would be a lot quicker to figure out if we can remove user error from the equation. 
    • If as it's stalling, the fuel pressure rises, it's saying there's less vacuum in the intake manifold. This is pretty typical of an engine that is slowing down.   While typically is agree it sounds fuel related, it really sounds fuel/air mixture related. Since the whole system has been refurbished, including injectors, pump, etc, it's likely we've altered how well the system is delivering fuel. If someone before you has messed with the IACV because it needed fiddling with as the fuel system was dieing out, we need to readjust it back. Getting things back to factory spec everywhere, is what's going to help the entire system. So if it idles at 400rpm with no IACV, that needs raising. Getting factory air flow back to normal will help us get everything back in spec, and likely help chase down any other issues. Back on IACV, if the base idle (no IACV plugged in) is too far out, it's a lot harder for the ECU to control idle. The IACV duty cycle causes non linear variations in reality. When I've tuned the idle valves in the past, you need to keep it in a relatively narrow window on aftermarket ecus to stop them doing wild dances. It also means if your base idle is too low, the valve needs to open too much, and then the smallest % change ends up being a huge variation.
    • I guess one thing that might be wrong is the manifold pressure.  It is a constant -5.9 and never moves even under 100% throttle and load.  I would expect it to atleast go to 0 correct?  It's doing this with the OEM MAP as well as the ECU vacuum sensor. When trying to tune the base map under load the crosshairs only climb vertically with RPM, but always in the -5.9 column.
×
×
  • Create New...