2.8 vs 2.9??

[double-6s 0]

Hi.

Can someone please explain, in dumb fella's terms, the difference between the 2.8 and 2.9 vr6s?

what is different and where is it?

Many thanks.

Will

 

OOh, and wher can i get a vr6 crankshaft? :)

[G 0]

I dont actualy know the difference but I would imagine the 2.9 has got a slightly higher stroke (distance the piston moves) which is usualy done by having a different crank and not by using different sized pistons/block. This would give different engine characteristics.

[double-6s 0]

as far as i know the cranks are all the same so i'm not sure about that? how does a different size piston change the capacity? how is it measured?

[G 0]

its measured by the volume of the bore (piston surface area) x the stroke. So a different crank is the easiest way of doing it.

 

Another easy ish way would be to use a different head with slightly more/less area at the top of the cylinder.

 

SOmeone correct me if im wrong though. Thinking about it that second way of doing it might just change the compression ratio

[G 0]

I've just done a google search and found on one forum the bloke thinks the bore size is 1mm more on the 2.9. Not sure if its accurate or not though.

 

That is another way of doing it but is abit more difficult for the manufacturer because it means using different spec engine block, head and pistons.

[veeDuB_Rado 0]

100CC

[G 0]

lol we know that :lol:

[veeDuB_Rado 0]

Sorry, it was the Stella :oops:

[VWci 0]

AAA is 2792cc

ABV is 2861cc

 

AAAs bore/stroke is 81.0/90.3

ABVs bore/stroke is 82.0/90.3

 

as you can see bore is different...ABV has bigger bore.....

[GIXXERUK 0]

i was told its 1mm extra on the bore , you can rebore a 2.8 to a 2.9 so as above the stroke is the same

there are a few ancillary differences such as the TB

[dr_mat 0]

.. I'm told the 2.9 also has different inlet manifold and cam profiles.

[Guest]

yeah the 2.9 manifold and throttlebody are different, the latter makes the biggest difference being of a bigger diameter than the 2.8 throttlebody

[Pau1 0]

Nice 2nd post there Bigshow. Loving the new VR6 now are we?

[Kevin Bacon 5]

The OBD1 2.8 and 2.9 throttles are the same bore. The smallest bore is the 2.8 OBD2 stepper throttle. Both 2.8 throttles have a ramp in the throat and a direct linkage. The 2.9 has no ramp and an indirect link to slow down the initial opening, which mimics the behaviour of the 2.8's ramp.

 

The smaller OBD2 throttle and manifold give a better response lower down as the narrower bore speeds up gas flow, which improves torque.

[double-6s 0]

ok. can we have some plain english spoken here purleeese!

 

if one had a 2.8 mo fo, what would one need to do to change it into a 2.9 mo fo??? just out of interest.

[GIXXERUK 0]

double-6s, do have a dead 2.9 mo fo take rape bits off ?and you want to bore out a 2.8 mo fo btm end ?

or do you just have a 2.8 mo fo

[double-6s 0]

my two wheel loving friend you understand me exactly.

i have a potentially dead 2.9 mo fo, and a worn 2.8 mo fo. idea was to get 2.8 to 2.9 spec without C being off road whilst it gets done.

also saw a brand new 2.9 block on the bay. so if i could get that, what would i need to do to the head of the 2.8 mo fo to make it sit atop the 2.9 mo fo block?

am i making any mo fo'ing sense???? :) :) :)

[dr_mat 0]

2.8 and 2.9 have the same cylinder heads, so should fit together immediately, with no probs.

[Kevin Bacon 5]

LOL! The mo fo VR parts are all interchangable.... the only major difference between 2.8 and 2.9 (other than my throttle and manifold bullschitt) is the mo fo bore. Stick your mo fo 2.8 head on that new mo fo 2.9 block and you're good to mo fo go.... :-)

[double-6s 0]

LOL!

 

thanks guys. thats exactly what i wanted to mo foking hear!!!!

so basically i can get my 2.8 head rebuilt, get that new block if poss, and the C will only be off the road for a couple of mo fo days?

in theory ;)

[Kevin Bacon 5]

Yep, that's the mo fo plan ;-)

[GIXXERUK 0]

fo sho mo fo :-)

[Guest]

Nice 2nd post there Bigshow. Loving the new VR6 now are we?

was bored today after i washed the vr, its too reliable, my other vw's always need something done but this one needs nothing. now im stealing this boys thread just to get more posts.

[selbekk 0]

mo fo.

[double-6s 0]

off to bid on that block then.

cos i'm a 12v man through an through. you can all keep your 24s and r32s

mo fo's :)

 

 

 

 

 

can i just add before the abuse starts........if i had the money i'd be getting a 32!! ;)