2.8. using 2.6 intake ?
 

Hi all.
I'm new here so hoping someone can steer me in the right direction.
I am in sa and have picked up a 97 model a4 which was running a abc block 2.6.
That engine is toast as it snapped a valve which then wrecked the piston the head and the bore.
I have picked up a 2.8 aah bottom end and a couple of heads.
My question is can I fit the abc sump, heads, and inelet and exs manifolds to the aah block and expect the ecu to have enough variance to fuel the 2.8 stroke and bore or will it cause havoc.

I have looked over a lot of threads here and see people trying to run the 2.8 inlet on the 2.6 but I'm trying to go the other way round.
Sorry if this has been discussed a million times before and thanks for any help you guys can offer.

Dave

The ECU shoudlnt have any trouble adjusting mixture for such a slight increase. I would think you should be just fine. Worst case it might run a tad lean and net you better economy lol.

Hi thanks for the input.

I'm fairly sure it will be ok but there must be someone here that knows for a fact or near enough... The prob is in sa every part costs a fortune so not a great plan to play the hit and miss game.

Cheers
Dave

I'm with Prospeeder here, you should be fine. i would not use the 2.6 intake on the 2.8 though. port and polish the 2.8 intake and you will be good.

I think he was saying he bought a 2.8 short motor and wants to put all his 2.6 accessory parts on it including the 2.6's ECU, Inlet and Exhaust.
So he won't have a 2.8 Inlet.
So he'll have slightly less airflow, not slightly more...

Firstly, don't worry about the sump, they're the same part number.
Camshafts, timing and accessory belts are the same too.

The 2.8 is merely a 5mm stroked 2.6 with marginally higher compression ratio (10.3 vs 10.0 : 1). You could just about substitute your 2.6 crank and build another 2.6! (I wouldn't).

I can't find the different inlet runner bore sizes for the 2.8 manifold vs the 2.6...
I know the 2.8 has 42mm bores (part no. 078133205D)
You could measure yours prior to fitment (part no. 078133205E)
I doubt there'll be much in it.
The throttle bodies have a different part number too, but I have no idea what the difference is.

Thanks marty

Yes your right I only have the bottom end of the 2.8 but it was fully re built with new oil pump, bearings, pistons etc so would rather use that and run it as a 2.8.

But as you say I only have all the other parts from the 2.6, I am thinking at a last resort I can port the 2.6 intake maybe turn up the fuel preasure a bit and even tamper with the ecu temp sender to feed it more fuel if needed.but I'm fairly confident it will run even as standard.

Thanks to everybody for there inputs and any other help is always welcome.


Cheers dave

I think it will run fine standard.
You may even get power somewhere near the 2.8 figure - depends how the ECU copes.

Messing with temp sensor won't get you more fuelling AFAIK, the temp sensor only tells the ECU when to use open loop and closed loop parameters. You'd need to mess with the O2 sensors if anything, but I doubt you'd have to.
I reckon the 2.6 ECU will have enough tolerance to cope with extra fuelling of the 2.8.
You won't need higher rail pressure - both the pump and the lines flow more than enough (though you could always get a set of higher flow rate injectors!).

Thanks for your input

Looking at everything I was fairly confident it would run and the ecu would have enough variance to adj for the differences.

Well time will tell.

It will take me a while to get it done but will post the findings when I have it running.

Cheers
Dave

If it helps, I used a 2.6 manifold on an old 2.8 AAH CQ while the manifold was off for port and polish.

The car ran fine, just felt a bit restricted. I got no issues with fuelling and no faults. I was glad to go back to the proper manifold though!

Manual to swap
 

from Russian tuning fan club, how to change inlet manifold on 2.6 ABC, from 2.8 AAH, with all parts and settings included