How do I make the best 16v for my style of driving?

[sports racer]

As the title says I'm looking at making the best 16v motor I can from the parts I have.

Somehow I've managed to get a KR with a damaged head (cams are still good), a 9a and an ABF that needs a rebore. I'm going to put the 9a into my MK1 but there are recommendations I should fit the intake cam from the KR into the 9a for more power. Someone else says to use both of the ABF cams in the 9a. Another combo is supposed to be the ABF block with the 9a head but I don't see how this is better than using the complete 9a.

I don't want an engine that develops it's power way up the rev range which is why I'm not going to put the ABF into the Golf. I prefer something that has good useable power around 3000 rpm which is where I do most of my driving.

Whatever combo I use will be fed by a pair of Dellorto 40's. Exhaust will be a Euro downpipe (4 into 2 into 1) going to a 2 1/4 inch system.

Suggestions?

Cheers

Paul

[Vinda76]

What's your style of driving? - this will drive the cam choice. From ClubGTI tests (Mr Hillclimber) the ABF head flows better as standard than the 9a head. ABF block is newer design, but not sure if there is much to it. Nice problem to have though. Gav

[sports racer]

The ABF is a much better engine but it develops its power up around 6000 rpm and max torque is at 4600 rpm. The ABF is great if you are racing, lousy for highway cruising. Max torque on the 9a is at 3500 rpm so it’s much more useable.

What I’m looking for is a magical combination that gives me lots of low down torque combined with a good top end that has more power than the 9a normally produces. It’s probably not possible but you don’t know if you don’t ask.

[Preen59]

ABF uses longer rods and has a taller deck. Has a slightly better head off the shelf.

All the 16vs make great torque- More than an 8v- across the entire rev range. They're a better engine in every way. All of the VW engines are undersquare (longer stroke than bore diameter) which is why they all make good torque. The ABF makes more top end power but that's relative. It makes more power full stop.

Use the KR cams or the ABF cams. If you use twin 40mm Delortos it's never going to be awesome down low. You won't have the air speed for it. If you choke them down they'll be pretty good, though.

[h100vw]

I had a MK3 16V and it was great on motorways, happy doing 70 mph or 100 all day. I once drove to London early on a saturday morning. Only backing off for the tolls. Was indication 100 most of the time, still made 30mpg.

If you dribbled around at 70 it would run well past 40mpg.

In a MK1 it would have to perform better still with less weight to pull around.

I never found the ABF a peaky engine like a KR or 4AGE.

Gavin

[Notso Swift]

If you use twin 40mm Delortos it's never going to be awesome down low. You won't have the air speed for it. If you choke them down they'll be pretty good, though.

Choke it down and he will lose the top end, though

I support Preen on this Often cars with better overall torque feel like they have less because they come on at the top end, but that doesn't mean they have less at any point, just when the other one drops off the other steps it up
Really need to look at the exact curve on the same scale.

Remember, the lighter car will help any torque hole, as well

[sports racer]

Sounds like the best option would be to put the 9a in now with the KR intake cam (exhaust cams are identical) and rebuild the ABF to put in later.

[Preen59]

I'm aware that if you choke carbies down, you'll lose maximum CFM and therefore top end.. As stated that wasn't an issue.

Yep. I'd do that. You won't have a peaky engine in the Mk1 with KR cams in a 9a. A KR in a Mk2 isn't peaky at all.

[gldgti]

Use 1 carb? If you really arent interested in the top end being raucous, perhaps just using a single carb would be better? Certainly for economy it would.

(It actually sounds like you want a diesel to me! )

[sports racer]

A tuned 2.0 TDI would be a perfect motor in a MK1. I've been looking at some of the conversions on Club GTI and they are boasting 280 hp and 55 mpg.

Now that would be something I could live with every day.

The reason I'm using twins is this is what came with the car. Lots of room there to put longer trumpets if it will help.



And they look awesome!

[sports racer]

After doing some research it seems a good combo is the 9a block with the ABF head. The 9a block is normal height so no clearance problems if I decide to fit the fuel injection off the Seat and the ABF head has the following advantages over the 9a head:

Small 27mm dia exhaust valve on 27mm seat for improved flow of hot exhaust gas
Cooling passages in the exhaust port to reduce hot spots and improve durability
Cooling channels in inlet port to improve/vaporisation and wall warm up.
Cooling passages in the combustion chamber to reduce hot spots and improve durability.
Improved squish areas working with revised piston.
Optimised valve shrouding on the inlet toward spark plug hole
optimised head shape around the shrouded part of the exhaust valves.
Reduce valve guide protrusion.
Reduction in port casting imperfections.
In/Ex Port flow improved over "51***373" heads.

Late model 9a motors had the same head casting numbers as the ABF motors so there shouldn't be any problems fitting the ABF head. The only difference was the inlet and exhaust cams.




This is the bit that convinced me to use the ABF head. It develops more power and it has a similar torque curve to the 9a so running the wilder ABF cams isn't going to kill my low down torque.



Lots of info here.

A VW 16v camshaft study.

[Mk1@4Motion]

Why don't you just run the ABF with a small turbo?


Only The Good Die Young 45

[sports racer]

I don't want that much HP. This car is being built to do the drive to Canberra and back each day and I don't want something that's too fast like my old Bolwell Nagari (1000kg, 350 hp) which kept eating my licence.

I like the idea of having something that will overtake cars but still need a bit of planning before I overtake.

[gldgti]

Keep it basically stock then I reckon. It should be perfect!

[Mk1@4Motion]

Yeah, just rebuild the ABF with a few internals changed for a bit more power.


Only The Good Die Young 45