[InFiD3ViL]

Originally Posted by SlingShot

I've always wondered how well that type of engine swap was. It just seems to me it would be a pain going from a L99 to LS3 would be a pain as far as the computers go and reprogramming.

Was very easy for me and did it in my driveway this summer.

Hydrolocked my L99 in June, bought a used LS3 a month later and had it freshened. New bearings, rings, springs, lifters, etc. New engine already came with a Melling 10296 HV oil pump.

Anyhow, removed my L99, installed the LS3. Used my L99 balancer. I did have to buy a wiring harness from Texas Speed for my cam sensor. The L99 uses a 5-pin connecter while the LS3 uses a 3 pin. The adapter made it super easy and was $20. Also, you won't use your LOMA connecter for the L99 AFM valley plate or the Cam Phaser connecter. I just tied those off. I removed the pilot bearing from my LS3 as it came out of a Camaro SS with manual, of course. Bolted up my L99 flexplate in place of the LS3's flywheel and clutch assembly.

Aside from the tune, there were NO major changes at all. I had DynoSteve make me a new tune for the LS3 optimized for the A6 and really, that was it. I also re-routed my catch can as the L99 and LS3 have slightly different PCV systems, with the L99's being superior.

So bottom line, if you have a complete LS3 to swap in, it is simply a matter of getting a new tune, a cam sensor adapter, and tying some unused L99 connections off. I may be forgetting a few small steps but it really was no bigger project than if I was installing a new L99 instead. Everything else is a direct swap and fits like factory.