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Tue Mar 27, 2012 8:04 pm

have a 94 westfalia 2.5L 5 cyl gas engine code AAF

took head off to shave .040 off to obtain better then 8.5 cr ....
porting also , cold air intake , but the original exhaust manifold looks restrictive with a bellow between no: 2 & 3 cylinder .

aint there a better manifold for these 2.5L ?

Tue Mar 27, 2012 8:06 pm

some mods done yet !

head ported ....

Tue Mar 27, 2012 10:15 pm

BigDan1 wrote: have a 94 westfalia 2.5L 5 cyl gas engine code AAF

took head off to shave .040 off to obtain better then 8.5 cr ....
porting also , cold air intake , but the original exhaust manifold looks restrictive with a bellow between no: 2 & 3 cylinder .

aint there a better manifold for these 2.5L ?

The later ACU engine in 95-96 has a two piece exhaust, redesigned to fix the cracking issue on the AAF exhaust manifold. It would require a different downpipe to the cat also.

Here's a pix:

http://www.jimellisvwparts.com/showAssembly.aspx?u...rchString=

These are pricey ($527 at Europarts), but I happen to have one on my spare ACU engine. PM me if you are interested.

Wed Mar 28, 2012 6:48 am

just to be warned and carefule of changing the compression ratio.
the AAF engine does not have engine knock/predetonation control for the Ignition timing and I've seen engines with serious piston & cylinder head problems from predetonation.. my 93 AAF engine included..
the 95+ engines had higher compression & knock sensors for ignition timing.
that change only gained them a few HP to 114hp from the 109 in the AAF engine.

if you want more performance and fun in your 5cyl EV, I'd suggest go whole hog and upgrade to an Audi 5cyl Turbo engine.. 8)

but enjoy it no matter,

Wed Mar 28, 2012 10:48 am

Did you cc the cylinder head combustion chamber before and after? There are online compression ratio calculators where you plug in your measured variables and it calculates your compression ratio for you. Since you only decked the head, you can run the numbers in the program using different thickness head gaskets as long as you know the original volume of the piston and combustion chamber. Running a higher octane will help fight detonation. Also less engine timing. Otherwise it is a crap shoot.

Wed Mar 28, 2012 8:28 pm

on a relatively small dia. piston like mine taking .040 off the head face shoulndt give more then .8 ratio ....
the ACU is at 10 to 1 ....

the AAF ,at 8.5 cr it`s definitely not power efficient !

ill put some 91 octane fuel after ...

head is ported for better flow , throttle body restriction removed , will have a cold air intake ...
if I can find a 95-96 exhaust manifold (thanks tdf3pete ) to obtain better flow and 2.5" exhaust

should give relative good numbers .....

Sat Apr 14, 2012 5:29 am

found a 96 manifold & down pipe at barely 10 miles away from my place lolllll

combined with a better flowing exhaust 2.5" and a cold air induction ,it should give good results ....
the 5 in 2 in 1 design is better then my previous ,,
cant be worse then the leaking 94 manifold ....

Sat Apr 14, 2012 11:27 am

BigDan1 wrote: found a 96 manifold & down pipe at barely 10 miles away from my place lolllll

combined with a better flowing exhaust 2.5" and a cold air induction ,it should give good results ....
the 5 in 2 in 1 design is better then my previous ,,
cant be worse then the leaking 94 manifold ....

What a great find. Congrats!

Wed May 02, 2012 9:37 am

Can I reuse original bolts to torque the head back on block ?

Wed May 02, 2012 11:57 am

Your book should specify whether the head fasteners are one-time use or not, BUT if it doesn't, you can tell by the torque method that is specified.

If the torque method is to simply tighten to a particular final ft./lb. (or Nm) figure, even if it says to get there in several torque stages, then the bolts are OK for a second use.

If the method specifies final torquing to a torque figure, AND THEN turning the bolts an additional number of degrees of rotation, then the bolts are being torqued-to-yield(TTY) and you would be wise to get new ones.

Wed May 02, 2012 1:32 pm

I dont have any book .....

ill do a research !