My mk2 track car/fast road project is currently sat gathering dust in the garage in need of an engine and that's where I have a bit of a predicament. I have some bits for a 16v engine, including a bare, ported head, a bare block which has been bored to 82mm and clearanced for a 2.0 crank, and what I think is a 92.8mm crank, plus various little bits like the oil pump, but that's it. No cams, no valves, no rods and pistons... I'd either need a donor engine to pillage for valvetrain and I'd still need to find pistons the correct diameter, or I'd be looking at trying to source everything brand new, which might be ok but I think some parts (like the rear cam sprockets) would be tough to get hold of. So I'm wondering if it's the right choice. Obviously it'd be more period correct but in 2024 is there a better option than a 40 year old engine? Ideally I'd like to keep it 4 cylinder as I have a nice fresh 02a to use so from what I can see, my options would be; 1. The 16v with ITBs 2. A 20v of some sort with ITBs, possibly ALT based for the extra capacity and lighter block? 3. The 20vT cop-out Obviously the NA 20v poses it's own set of problems, and I know there's been a lot of talk about them over the years where the consensus was that it suffers with small valve buckets limiting the cams. Pistons are also nowhere near as easy to find with a 'high' compression ratio, an inlet manifold is easy enough but an exhaust manifold would need to be fabricated. But these days, with the fact that they're much easier and cheaper to buy, plus a lot newer than the 16v engines, are they actually a decent option? I'm not sure if I'd want a 20vT even though it would be the simple way to (completely arbitrarily) 200bhp and it might be the better option for a car used on the road with the extra torque. I just don't know if that's what I'd want, I think I'd rather the induction noise. I know that ultimately the only person who can make my mind up is me, but it's always good to get some other opinions. And finally, like I say, I know there's been discussions over the merits of each engine on here but a lot of that is in threads from a long time ago and whatever might have been the easiest option in 2004 might not be 20 years later. I'd appreciate any input.
I suppose there's also a couple more options but they're even less simple. I could go for a 24v VR6 for the sound but it's very heavy. Then there's the options outside of the VAG family like a Honda K series (expensive), or a Volvo T5 if I did want a turbo, but both of those would require everything to be custom and that's outside my skill set. I think a bolt in solution is best.
I would think buying a complete engine would be your best bet cost wise. The problem with that is you don't know the engines condition. As you say the final choice has to be yours.
The VR6 is not that much heavier than the 2.0l AGG we had. Maybe 20kg. Bang for buck it is a great option.
I think my mental barrier is that either way I need a complete engine. If I decided to go with the 16v it would be stupid not to utilise the parts I already have and because that means buying pistons to suit the bored block, I might as well sink that £600 (or whatever) into a 20v if it's the more logical option.
Was that difference with a 12v or a 24v? That's not a huge amount, but the other problem would be that I have a gearbox which wouldn't be compatible, and that seems a waste.
Sometimes getting the thing that you want can mean there being more work or expense. Reading between the lines I think you've a very clear idea in your own mind of how you'd like the car to be (in an ideal world), but are weighing up the less difficult alternatives / lesser options as they may be more straightforward / cheaper... and there's nothing wrong with that. I think however you'll need to ask yourself are you going to ultimately be happy with whatever solution you settle upon or will you potentially look back upon it as a compromise, maybe made for the wrong reasons?
I'm not really sure what I want to be honest. I've always wanted something with ITBs but I know that's not the most logical choice. Even a standard 180/210/225 engine would be way more useable and considerably cheaper. If I was replying to someone else's thread, I'd tell them not to bother with the NA option but who ever listens to their own advice?
Ours is an R32 24v from an Audi TT. You may have a gearbox but you can always sell it and get the correct MK3 VR6 O2A. Things to consider though are loom, ECU and all the other little bits that need changing, they all add up. More power means you need an LSD. Does your existing box have one? Its swings and roundabouts. Best bet is to decide how much horsepower you want and work back from there. Do you want to be able to drive to the cars limits or have that extra power for the longer straights on different tracks. So much to consider
The gearbox I have has an open diff, so you make a good point. I don’t have a power number in mind really. I’ve had several Clio 182s, and their 1100kg/170bhp was nice, useable fun. This car will be lighter with a similar engine, so something around that number would be plenty. What I don’t want to do is be backed into a corner where it’s easy to get to 180bhp (for example) but impossible to get much further without using some unobtainable VWMotorsport cylinder head or something stupid.
If you want to break that barrier you'll need to go turbo anyway in my opinion. Getting 180bhp is already more than simple. I haven't got a ported head, but catcams, ITB's, stand alone ECU and the engine is freshly built, which delivers 201 hp/ 141 bhp. To get 40 bhp more the head will need serious adjustments, porting, welding the injector holes, mechanical valves and probably other pistons, then the catcams can be adjusted to perfection, but that takes someone with a lot of experience and a lot of dyno time. This means serious money if you ask me and to make the car faster a 20vt would be the simplest and probably cheapest option. Way more torque due to the turbo and more HP by increasing the turbo pressure...
Thanks for the reply. It's good to hear from someone who has direct experience. I had already pretty much decided on an NA 20v but I bought an inlet for DCOE fitment which I've received today and it's a very rough casting. The ports on the throttle body size are only 40mm and the cylinder head side they're 34mmx60mm, which is way bigger than even a large port 20v head. I don't think there's enough material to enlarge it to suit 45mm or 48mm throttles. I'm a bit disappointed because it wasn't cheap and I think it's been a waste of money.
I went 16vG60 but I think if I were doing it again from scratch it would be a 20v Turbo. I mulled over building a NA on throttle bodies / bike carbs but decided I liked the low rpm power from the Supercharger and kept my G60 conversion. Each to their own, I can see merit in having a high rpm na on throttle bodies, the noise would be amazing. At the end of the day it's your car and your decision.
