Will any polo gearbox fit my 16v? really need help

Acemo · Post by **Acemo** » Wed Apr 09, 2008 8:04 pm

hi, my gearbox blew up today lol, completely shatterd, so im going to buy a second hand one, will any normal mk4 gearbox fit, or do i have to get a 16v one?

cheers

Tim_GTi · Post by **Tim_GTi** » Thu Apr 10, 2008 3:19 am

If they're anything like the 6N2 ones (which I highly think they will be), the boxes will be the same, but the ratios will be different

The_phat_controlleruk · Thu Apr 10, 2008 12:18 pm

That's really weird, my engine code is APQ and I recently had a recon gearbox from an AEX coded engine, and the fifth gear seems much taller than what I am used to, never occured to me different gearboxes have different ratios (it could be me though)

Tim_GTi · Post by **Tim_GTi** » Thu Apr 10, 2008 12:22 pm

Yep, the different gear ratios for the 6N2 can be found here

http://www.tyresmoke.net/gallery/albut34/DSC02262

http://www.tyresmoke.net/gallery/albut34/DSC02263

NOZ · Post by **NOZ** » Thu Apr 10, 2008 1:14 pm

Yep ratio's are always different depending on what VW choose for whatever engine. For example different ratio's would apply from a 1.0 to just say a 16v. Shorter ratio's on a 1.0 allow more power at lower gears for town driving whereas the 16v can cope and therefore use longer ratio's.

Acemo · Post by **Acemo** » Thu Apr 10, 2008 1:51 pm

so if i put a 1.4 8v gearbox in my 1.4 16v polo, it will go slower?

also i need a second hand clutch, will they be the same?

NOZ · Post by **NOZ** » Thu Apr 10, 2008 2:27 pm

Depends on the ratio's of either spec gearbox.

Example an 8v tops out in 5th at 105mph but a 16v tops out at 125mph. If you put the 8v box in the 16v then you'd be hitting the limiter too early and therefore go slower (if ratio's work out that way). Its probably best to get a 16v gearbox mate. I'm in need of a 16v one as 'phat controller' knows so saving up

dragon_green · Post by **dragon_green** » Thu Apr 10, 2008 6:23 pm

I've tried to explain gear ratios a few times, do a search and you should be able to find something

polo-sib · Post by **polo-sib** » Thu Apr 10, 2008 7:12 pm

Its hard to explain, I understand it but I'm not a good teacher, so shoving any gearbox in that would be from an 8v or a smaller size/spec model would result in far more acceleration.

So basically a lower spec engine gearbox will give you more acceleration, but will lower your top speed (and the time it takes you to reach top speed) by a bit due to a lot of your energy will be converted to acceleration. Thats the disadvantage you'll face if not going with the standard gearbox. But if you like acceleration over top speed then go for it!

As for the clutches I remember theres a difference between the 1.0 8v and the 1.4 8v clutch kits, so I'm not sure but I'd imagine the 16v would have something else, I'd recommend buying a new clutch as you don't know how good a second hand one will be and how long it will last you, so just go all out and get a new clutch that way you will know it will last you quite a long time before another change.

Hmmmm gonna give you an example of the gearbox change (not very accurate)

Standard gearbox
x|
x|------------------------------------x----max125----------------------
x|--------------------------------x---------------------------------------
x|----------------------------x-------------------------------------------
S|------------------------x-----------------------------------------------
p|------------------- x---------------------------------------------------
e|---------------x--------------------------------------------------------
e|-----------x------------------------------------------------------------
d|-------x----------------------------------------------------------------
x|---x--------------------------------------------------------------------
x|x-----------------------------------------------------------------------
x|____________________________________________________
TIME

Lower spec engine gearbox (the start of the curb will become sharper and shorter making you reach your new top speed faster)
x|
x|-------------------------------------------------------------------------
x|-----------------x----max105-----------------------------------------
x|---------------x------------------------------------------ -------------
S|------------x-----------------------------------------------------------
p|---- ----- x------------------------------------------------------------
e|--------x---------------------------------------------------------------
e|-- ---x-----------------------------------------------------------------
d|---x--------------------------------------------------------------------
x|-x----------------------------------------------------------------------
x|x-----------------------------------------------------------------------
x|____________________________________________________
TIME

NOZ · Post by **NOZ** » Fri Apr 11, 2008 11:48 am

Line gets shorter for speed and time. You get to your top end quicker meaning acceleration is faster to reach it. However, cos 5ths shorter your top speeds lower then standard cos you've hit the limiter earlier. The engines capable of more but the gearbox will hault it there. Also because you'll hit the limiter the revs will bounce back down and running the revs in the red will cause more stress on your engine.

I think the clutches would've been different too cos the cars differ BUT I don't know. Say this cos I doubt a clutch made for a 1.0 could cope with a 16v power.

david burton · Post by **david burton** » Fri Apr 11, 2008 12:08 pm

NOZ wrote:Depends on the ratio's of either spec gearbox.

Example an 8v tops out in 5th at 105mph but a 16v tops out at 125mph. If you put the 8v box in the 16v then you'd be hitting the limiter too early and therefore go slower (if ratio's work out that way). Its probably best to get a 16v gearbox mate. I'm in need of a 16v one as 'phat controller' knows so saving up

This isn't completely true. An 8v engine will redline at 5k (for example) whereas a 16v will redline at 6k (for example). Therefore if the 8v box tops out at 105 at 5k rpm, the 6k point (16v engine) will be 20% higher, and approx 126mph!

Therefore you might actually get away with an 8v gearbox in a 16v. Just need to be able to get the specs of the various ratios.

From what I remember, the ratios on the 16v are actually shorter than the 8v because it revs higher and wants to sit at higher revs on the motorway. so you will find that putting an 8v gearbox in will give you a better economy on the motorway but worse acceleration.

wadders · Post by **wadders** » Fri Apr 11, 2008 12:29 pm

Davids correct. I had a 16v that had three different gearboxes, all replaced under warranty. The second one they put in was an 8v and the acceleration was pants. It was great on the motorway!

NOZ · Post by **NOZ** » Fri Apr 11, 2008 3:18 pm

We've been waiting for you guys to show up on this topic lol! Understand it theoretically but I don't know the polo gearbox's as such so been waiting for answers. Obviously I didn't take into account the differences, I forgot. What I was saying would've been right though if they redlined at the same point, right? Just wanted to understand it.

Anyway, as David said about the differences in the revs then thinking it i'd expect that to happen.

Acemo · Post by **Acemo** » Sun Apr 13, 2008 11:32 pm

ok, ill be searching for years trying to find a 16v gearbox round here,

it wil be arite though i will find one somewhere

cheers for the help!

NOZ · Post by **NOZ** » Mon Apr 14, 2008 11:56 am

^^ Let me know if you find one and if the place has another! i need one too