Uprated injectors for tuned 8v?

I have an 8v bored out to 2.0 with big valve head,exhaust e.t.c. I'm keepin the kjet system with WUR mod and I'm havin the metering head reconditioned, the guy doing it says he can also increase fuel flow at the same time by possible increasing cap size and omitting some restrictive filters before the banjo connectors (his words),
I was wondering If anyone had looked into different or uprated injectors ? I'm currently going to get the standard ones flow tested and spray pattern checked at local fuel injection specialists.

Good luck with that, I would be nervous about messing with the set up of metering head as they are so sensitive.

I have just fitted a set of new Bosch injectors to my 1.8 DX that I have checked the part number on and they are compatible with a 2.2 litre Mercedes engine so shouldd be ok for a 2 litre.

I have had the fuel flow adjusted and air setting on throttle body and it runs as sweet as honey.

These are still available from Bosch injection specialists so they are no doubt the best to ask.

The k-jet injectors are good for about 180 to 200 bhp after that they cannot flow enough fuel.

It is good to flow test (volume delivered in a certain time period) and check the spray pattern of the injectors. You can simply do this by pulling them from the head and put them in jars, bridge the fuel pump relay and then lift the metering flap. An easy at home test.

K-Jet injectors cannot be cleaned, sure you can have them opened under pressure and cleaner run through them, but it will make little or no difference. any crud will just get pushed into the end of the injector !!
EFI injectors are reverse flushed while being operated and clean much more effectively.

You would really need to know what you are doing to alter restrictions in the metering head - the Bosch engineers spent many hours perfecting the shape of the cone that the air flap sits in and how it works with fuel flow.

The only thing that I have heard of is that you can tweak the amount of fuel flowed by each of the injectors to get a better balance. However it is often just easier to swap the injectors around.

If you really want to control the fuel and ignition better then it is time to just k-jet and go EFI.

If I was you I would get it on a rolling road first and see if it is under fuelling before messing with a very sensitive mechanical injection system. If may be that just tweaking the WUR's upper control pressure will be enough - remembering that this alters the fueling right across the rev range.

there are no uprated injectors that i know of, the brass ones off ebay are same spec as std vw but fitted to merc, porche etc.

the metering head itself can be changed to adjust the fuelling, and you can also get motorsport air assembly with machined bowl, but these arnt so easy to find.

if you can find one a k-star + fuel kit will allow you to tune the fueling right across the rev range, assuming you can find someone with the skills and cable to set it up!

to start with get it tuned and check how its doing with an afr gauge, after that you can decide what if anything needs doing.

for the long term i would advise junking the k-jet system entirely and go megasquirt or similar. k-jet is too old and clunky to get the very best out of a tuned engine unless you have a real wizard of a tuner.

Thanks for the advise guys.
I recently had the car on the rolling road, the mechanic was unable to get a rich enough mixture so following his advice I'm getting the metering head reconditioned.
I've just carried out the WUR/throttle body mod and have a K-jet test rig on order to set the pressures correctly…… then back to the rolling road!
My aim is to get as much power from the original setup as possible whilst keeping the original look and feel of the 8v engine.

Took the metering head off today and found one of the injector pipes was slightly blocked. Also got the spray pattern checked on the injectors by injection specialists, two were very poor and they recommended replacing all of them, so this is more likely my fuelling issue.
I've ordered some of the Bosch Mercedes injectors that fit.

Ive removed the metering head, the plunger moves fine and the visible o rings look fine so Im not sure if it's worth getting it done. KMI quoted me £300 + Vat! However there is a company on eBay America who'll do it for less than half that.

Hi danwall3000 I know this thread is really old, but curious anyhow on how this story ended up?

I also have a tuned 8v DX engine in my MK1 GTI. Although it is not running bad, I have the feeling it could be going better and the Kjet somehow is not performing on its best (still have to put it on the rolling road for finetuning though).