Bike carbs or similar, Worth it or not?

**jdrose** · 29-10-2010, 02:27 PM

Do it. ITB is awesome.

**ozgti** · 29-10-2010, 09:40 PM

Can you supercharge ITB/Bike carbs?

**h100vw** · 30-10-2010, 11:53 AM

Having been through all this in 96', I can say that a well fettled 1800 or 1900 8V is the best solution.

I had a MK1 GTI with an 1800 bottom end, TSR Pack C head, TSR 103 Cam, vernier pulley, exhaust manifold and an system. Dyno'd well over 160 at the crank.

It went like a train.

When the bottom end wore out I fitted a 2E bottom end under it which ruined the feel entirely. It was torquey but massively thirsty. To get adequate fuelling at the top end it ran rich everywhere else. The 1800 would rev like a 16V but the 2 litre was all in by 6k.

As an 1800 it would do 40 MPG at 70 on the motorway, 400miles on a tank was easy, as a 2 litre it wouldn't see 300 most of the time.

So the up shot is to modify the 1800 will cost you. The head, cam and vernier in 96 were over 1000 quid. Then there's the manifold and system. You need someone with Kjet knowledge to set it up. I can advise on that to a degree having taught myself about it.

My advice for an instant 30hp is to fit a 16V like I did in evorobin's digfant GTI. An ABF conversion would be the best bet. Having had just about every 4 pot made by VW since my first MK1 in 92, the ABF has always impressed me. The power delivery and throttle response and nearly K-jet like compared to the laggy nature of the mk2 digfiants.

I know we are in Australia but they are available.

A 16V KR cover with a plate to match the gearbox is the way to go for a clutch.

Brakes would be a sensible thing to upgrade too. 256mm would be a starting point.

Gavin

**Golf Loon** · 30-10-2010, 01:41 PM

You should probably rego it first mate.
It also seems a shame to mess with one of the first GTI Mk2s built and one of the few 2 doors out here.

**ozgti** · 30-10-2010, 08:43 PM

i will Mat, just need you guys to move first!!!

**ozgti** · 31-01-2011, 11:56 PM

Should I just rebuild the Kjet or go something else?

Matt, What did Beau say needed to be done? Just the intake gasket, plugs and leads?

**ozgti** · 30-04-2011, 11:27 AM

Why do bike carbs/ ITB/Carbs kill fuel economy?

**h100vw** · 30-04-2011, 11:45 AM

Getting the fuelling correct over a wide range of operating conditions with carbs is very hard to do.

Hence it will use more fuel than it could do in ideal conditions.

I have said it many times before, if carbs were so good, they'd be used in all forms of motorsport and still be in use on the road. The fact of the matter is that they can't hold a candle to fuel injection. Agreed they can make more power, that is due to you removing other restrictions in the intake system.

I would venture to state that a well set up carb system could not produce more power, than a well set up injection system.

Throttlebodies with injectors is something else entirely and could be made to perform at least as well as the standard injection system. The cost would be pretty high though.

Honestly, you can make a good Kjet set up.

If you go with a 2 litre bottom end, I would supplement the standard injection with a piggy back controller firing the cold start injector. The car would start normally without it connected anyway. How to Tune and Modify Engine ... - Google Books

That's the first link I came up with off google. I think there's some stuff in that Jaycar project book IIRC.

Needs to be triggered by engine load, so it has a vac input too.

The one I have used in the past, I can't find a link to it though.

Gavin