Injection Pump modification basics for 1.6 NA

[overdrivegear]

First of all, I know, I know, there is a plethora of information that I found doing a search for IP mods and the intimate details of how-to but I wasn't able to find out any of the theory.  So, you pump experts please enlighten me as to what benefit some of these mods do.  I'm curious because I just took apart my first IP yesterday and would like to tinker with it some.

Clearly the governor mod allows you to rev beyond some limited number of RPMs, but what real benefit do you get for this mod if the peak torque and power is made under the governed ceiling?

What is the point of an upgraded cam plate and higher pressure for the same angular position?

Stock pumps have a 9mm rotor and head, so going to 10mm, 11mm, and 12mm rotor and heads will increase fuel flow so does it necessarily mean that if you wanted to tune a pump, you'd have to upgrade the rotor?

[Rabbit on Roids]

your post was clear as mud.

Governor mod:
just because peak hp and torque are at 2200 rpms, that does not mean you can make tons and tons of boost that low. these engines will pull clear up to 5500 rpms or more if you tune the pump right. with a stock pump the fuel starts getting cut at about 4000 rpms. and you really notice the fuel cut too. the car falls right on its face.

Pump head:
stock pump heads are indeed 9mm, unless you got a eco diesel. dave cross was making 193 horsepower on stock size injectors and a 9mm pump head. so, no, you dont need a huge pump head to make lots of power, its just easier to get more fuel there with a bigger pump. it all depends on what you want to "tune" these pumps to do. you can tune them to get almost 80mpg, but there isnt gonna be much in the power department, also, you can do the exact opposite. make it have enough fuel for a smoke screen behind you, but it isnt gonna get much for mileage, but its still gonna get great mileage compared to a V8.

[madrogers]

 you peaked my interest, do you have any more info on the "80 MPG " side of the story / pump mod.

[theman53]

Gov. Mod:
I believe that at around 2,200 RPM it starts to limit fuel and around 4,000RPM it doesn't give you anymore fuel than at 2,200. I could be wrong on the exact RPM there but that is how it works. If you do the gov mod it will not start to cut fuel until later or at all depending how aggresive you are with it. By not cutting it then you will have more power throughout the RPM range over 2,200. I believe TinTin had a youtube video showing how the pump worked by spinning it with a drill and the top was off so you could watch the gov. assembly move. I can't find it though

here is a site to help:   http://mebonty.monobasin.net/vepump.html
That is from the FAQ

[Rabbit on Roids]

you peaked my interest, do you have any more info on the "80 MPG " side of the story / pump mod.

im not the one to talk about with the 80 mpg thing. i like making black clouds out of my fuel, im sorta wasteful. i dont remember much about it, bacause i read about it 5 years ago, but i remember a guy named hagar (i think??) on a different forum (once again, not sure.) and he tuned his IP's so he would get between 65 and 90 mpg. i dont know how he did it, but it was a long long long in depth article about tuning the pumps. he messed with dynamic advance, internal pump pressure, pretty much every aspect of the pump.

[VW_Commuter]

Hagar posts over at http://www.vwdieselparts.com/forum/ and his saga is in the General section in the post titled 'Old guy Old Rabbit---both Happy'.