I have a MY01 WRX spec as follows

Jap spec sti turbo
Jap spec sti injectors
Jap spec sti fuel pump
Motec M800
APS Front mount
APS induction kit

I am considering fitting a 2.5 short block into it
It obviously has the 5 speed box which I like but have heard that this might not be strong enough ? Is this correct ?
What sort of RELIABLE figures could i get from this conversion ?
Would I need to replace anything else ?

Sorry if this has kinda been covered before but I wanted exact details relating to my car before parting with the hard earned !

 

You will be able to reliably get the same power or ever so slightly more than you can already get out of your present setup as it will be turbo limited. You will get a wider, torquier power band though.

Your five speed will probably be OK if you stick below 300 lbft, which will probably be at about 0.8 bar.

 

seems that there have been several 6 speed problems too, judging by the number asking about sychros etc.

I thought the 5 speed casing was inherently weaker, but am now less convinced. Especially since the rigolis were running using 5 speed casings for ages.

and now trouts casing seems to handle the torque ok.

Also harveys and bobs standard 5 speeds with plenty more torque seem to be holding together. I suspect a degree of mechanical sympathy is required.

 

Both Harvey and Bob are running STi 5speeds though..

Who knows if the newage gearbox casing is stronger or not?

About time someone made some bracing frame for the box to stop it flexing..

You would Have to do a bigger Turbo!!

JGM

 

with the "gpN" rally cars, Prodrive use a six-speed casing and convert to 5-speed dog internals due to strength of casing!! must be some reason for this..................

 

Fulham, i still reckon you should keep your current setup as said to you yesterday.

Change turbo and put a better map on it and your laughing.

Then if anything goes wrong, then change to 2.5

 

The 6 speed was a completely new gearbox from day one, its inherently stronger than the 5 speed box it replaces on the STi's, you will find its not everyday that a manufacturer builds a new gearbox! (says something )

Tony

 

I thought the synchro problem was resolved on most with an oil change?

The only issue with the 6MT so far is it is too short geared for a torquey motor, at least with a 7000 RPM limit.

 

1st is ok, 2nd and 3rd are too short, 4th needs to be up to around the 130mph mark, 5th to the 155mph mark and 6th to the 190mph mark (well thats how id do it )

Tony

 

So it looks like I will need a new clutch, gearbox maybe one from an Sti5 & a new turbo to replace my VF30 ?
Plus maybe a new fuel pump ?

 

I would say new clutch and say use your gearbox to start off with. I think chrisjones was using his wrx gearbox on his bugeye and he was putting some very good power through it.

Turbo - Andy F special TD05/06

Fuel pump easy

 

Money
Hows you mate ?
You going today ?
Did you geta labour price for me mate?
Cheers
Paul

 

thanks for the info guys
Still not sure what to do !

 

Chris WAS using his 5spd, but broke it..

David

 

David
any ideas what power Chris was running before it broke ?
I want to do the conversion but the gearbox issues are causing me some concern
Also Does anyone know the limits of the VF30

Cheers
Paul

 

I have hear rumours.

Nothing major..

If your worried, then dont do it.

Replace the gearbox first.. = you can sell existing one.

Keep engine to one side prior to swapping box, then sell existing shortblock.

IMHO.

David