ABA/JH Swap by Moljinar

5 minute(s) of a 20 minute read

Got the gauges hooked back up and looks like I'm getting 28 -39 mpg!

10-24-2009

NY_Fam in the MK1 forum sliced open several dozen 8V intake manifolds and found all of them roughly the same on port size. He has a service where he will take your manifold and open it up and smooth all the transitions as well. Proven good for 6-10 hp on a stock engine!! I'm going to have it done myself someday.

Meanwhile the best thing to do is a larger throttle body such as from an Audi turbo 5000 or an A2 (requires modification) and then open up the manifold opening to match the larger throttle opening.

The exhuast is loud because I have a straight thru muffler (Dynomax I think) and with the race downpipe, no cat and TT cat-back system it's failry loud-ish. Add the punch of a ABA and it's louder. Nice bark and crackle. SOunds like a large tractor at intowen cruising but open 'er up and everyone takes notice!

Simply putting a regular hi-po muffler like a Borla on there sound be reasonably quite for you. 

KNock sensor wiring gets done tomorrow I think. Would've not been needed but I couldn't get the harness out in one piece so I have wires to splice. I have CIS-E distributor ready to go. 

If you are keeping the AC you'll have to use the AC that comes with the ABA IF you intend to keep the serp belt system. AND My info says that the AC lines won't bolt up without modification. You may want to visit someone's A3 to see what's what. If you use the JH's brackets and belts you'll be ok . And at that point powersteering would be no problem. 

The ABA in an A3chassis has no passenger side mount. It uses a funky rear/passenger mount you won't need/can't use. The holes were there for my A1 passenger mount but I know recall the threads weren't in good shape. I had to chase the threads with a tap to clean them out. Then my mount went on fine. As for the stock mount I have no issues. In fact the ABA seems to idle smoother and vibrate less. Possibly an effect of the longer rods? 

The more I drive this car I'm convinced this is what VW should've put in our cars from the beginning. Or at least made a GT version with it

The usual TT upgrade system is fine, no larger size needed unless you're thinking of turbo'ing it and even then maybe not. Size for size's sake is not really needed. The ABA downpipe TT makes for this swap is hefty in the first place and that's usually the major choke point of most systems. And yeah, too big will kill your back pressure (which actually helps out with torque.)

Frankly the biggest gotcha with this swap is the distributor setup. Today everyone cringes to think of using a centrifugal/vacuum advanced distributor with a high (10:1) compression engine. Frankly I remember several decades of high compression engines with no knock control but let's just agree that using VWs knock control system is what you want to do. 

You can't use a regular CIS distributor because it has cent/vacuum advance and can't be computer controlled. You'll need a CIS-E or Digifant distributor, neither of which have any timing adjustment in them. The both have 4-hole/shutter wheels which you'll need if you are using either the CIS-E knock sensor box (a separate ECU that hooks up to the ignition unit and the distributor) or the Digifant ECU which controls the fuel injection AND the ignition/knock. The ABA distributor has only 1 shutter wheel opening. It signals cylinder #1 while the OBD1 trigger wheel in the crankcase senses the crank position to allow the ECU to figure out the timing advance to use. This could be used if you are using the ABA's native fuel injection system or a standalone such as MegaSquirt or others.

Now with all that in mind and needing to drive the car immediately I put in the usual CIS distributor, set the timing to basic specs and unhooked the vacuum advance. Running premium with no more than 20* of total advance I'm doing fine with no apparent detonation. Ron will tell you that you can't sense the micro detonation that can destroy things and that's probably true. But it's a stop gap that seems to do fine for now. NOT a long -term solution unless you want to re-curve the distributor (lord the 60's and 70's were fun) Also once you put TTs gear on it's easy to remove and put on another distributor

The AC issue is not an issue for me. Do as you feel like. But I will say the serp belt setup is awesome!!

I have no upper timing belt cover ( I spent too much on the pretty timing gear, why cover it up?) so getting to the mount was no big deal. AS I said earlier it bolted right up. Only needed a spacer to make it lie down properly.