Conversion from Carbs to CIS to EFI, Using BITZ racing kit to convert to EFI Options

[bfrymire]

Hello everyone,

This is my thread to cover my conversion from Carbs to EFI. I will be using the Bitzracing CIS to EFI conversion kit, to replace the webers on the motor now, which is a 2.7l six. (And before anyone asks, I am not selling the carbs, yet. (IMG:style_emoticons/default/smile.gif) Want to make sure it works better before I unload the carbs.) (http://www.bitzracing.com)

Ok, I am sure someone will ask why. Well, I autocross the car every month, and drive sometimes on the street. The carbs, due to sitting, tend to gunk up and require regular maintenance, and because, I am hoping the car will idle better, and just in general be more well behaved street driving. (Hey, it may even polute less. One can hope.)

First step is to take it and have it tested on the dyno for a benchmark before any changes. (http://www.dynospotracing.com)

The kit is fairly complete with good instructions. (You have a few parts to source yourself, easy to get.)

As I go, I will provide more part numbers and details.

Here's a picture of the parts kit including parts I sourced myself.

[Dr Evil]

My 2.7 with CIS was nice. I almost had it dialed in...then I wrecked it. I still have the engine and it will be going into another car here soon.

The bus is getting CIS as well (IMG:style_emoticons/default/happy11.gif)

[bfrymire]

My 2.7 with CIS was nice. I almost had it dialed in...then I wrecked it. I still have the engine and it will be going into another car here soon.

The bus is getting CIS as well (IMG:style_emoticons/default/happy11.gif)

The fundamental design is good. EFI just makes it better. (IMG:style_emoticons/default/smile.gif) The ease of tuning really makes it great. (Of course all the other advantages are also good.)

Here's some dyno results off the bitzracing site:

"2.7 with CIS - 136hp at the wheels at 6200rpm
2.7 with EFI - 145hp at the wheels at 5800rpm before tuning
2.7 with EFI - 154hp at the wheels at 5800rpm after tuning"

I am really curious what mine is going to end up at: I have headers, and modified E cams and european pistons. I am hoping for at least 165hp at the wheels.

-- brett

[bfrymire]

Status update:

Fair amount of progress.

Most of the sensors, are installed. The O2 bung is welded into header. Here's a picture of the install, and you can see the air intake installed.



Ok. List of what to do:

1. Still need to plumb the fuel. Can't find a good location to mount the pump. I want something easy to access, but short fuel lines.

2. Re-install the header and install 02 sensor.

3. CIS linkage. This may be a problem. The motion of the carb linkage is wrong for the CIS. I may have to source some CIS linkage...

4. Wire the MS, and all the sensors. (This is the easy part. Should not take more than a couple of hours. In the words of Jeremy Clarkson, "how hard can it be?" (IMG:style_emoticons/default/biggrin.gif) )


Its getting close. I was hoping to be farther along. As usual, life got in the way. (IMG:style_emoticons/default/smile.gif)

-- brett

[rick 918-S]

Status update:

Fair amount of progress.

Most of the sensors, are installed. The O2 bung is welded into header. Here's a picture of the install, and you can see the air intake installed.



Ok. List of what to do:

1. Still need to plumb the fuel. Can't find a good location to mount the pump. I want something easy to access, but short fuel lines.

2. Re-install the header and install 02 sensor.

3. CIS linkage. This may be a problem. The motion of the carb linkage is wrong for the CIS. I may have to source some CIS linkage...

4. Wire the MS, and all the sensors. (This is the easy part. Should not take more than a couple of hours. In the words of Jeremy Clarkson, "how hard can it be?" (IMG:style_emoticons/default/biggrin.gif) )


Its getting close. I was hoping to be farther along. As usual, life got in the way. (IMG:style_emoticons/default/smile.gif)

-- brett

Nice work, I have CIS. I used a Volvo turbo pump and accumulator. I mounted it under tank. The Volvo has a pusher pump. Not the easiest to get to but if it's working correctly it's a done deal.

[bfrymire]

Nice work, I have CIS. I used a Volvo turbo pump and accumulator. I mounted it under tank. The Volvo has a pusher pump. Not the easiest to get to but if it's working correctly it's a done deal.

Thanks Rick. I am not a professional mechanic, and sometimes I think I am a hack. (IMG:style_emoticons/default/smile.gif) So, the kind words are appreciated.

Hum. You just mentioned something that I do not have. I did not put an accumulator in. Since, this is carbs, there just wasn't one. I understand that it's there as a reservoir for spikes in fuel demand. (For electronic guys, like a capacitor.) So, am I going to be at risk for fuel starvation?

And the other omission, is the IAC. I still haven't figured out what to do on this. (I can adapt the stock unit, use a jeep IAC, or just a hand throttle.

-- brett

[ArtechnikA]

...I did not put an accumulator in. ... I understand that it's there as a reservoir for spikes in fuel demand.... So, am I going to be at risk for fuel starvation?

No. And No.

The accumulator (in conjunction with the check valve that's typically incorporated into a Bosch CIS pump) keeps pressure in the fuel loop to assist hot starts. Specifically, it keeps pressure up to resist fuel boiling in the lines following a hot shutdown.

It's a good idea but you may be able to get away without one. If you start having hot-start issues, think about it. You do not need Porsche parts. There are hundreds of thousands of CIS-injected VW's and their parts for this will work just fine. Somewhere I even have the Earl's part numbers for the fittings and adapters you need to connect them with AN hose. If you're not using a Bosch pump, you'll need a separate high-pressure check valve. Earl's has those.

[bfrymire]

...I did not put an accumulator in. ... I understand that it's there as a reservoir for spikes in fuel demand.... So, am I going to be at risk for fuel starvation?

No. And No.

The accumulator (in conjunction with the check valve that's typically incorporated into a Bosch CIS pump) keeps pressure in the fuel loop to assist hot starts. Specifically, it keeps pressure up to resist fuel boiling in the lines following a hot shutdown.

It's a good idea but you may be able to get away without one. If you start having hot-start issues, think about it. You do not need Porsche parts. There are hundreds of thousands of CIS-injected VW's and their parts for this will work just fine. Somewhere I even have the Earl's part numbers for the fittings and adapters you need to connect them with AN hose. If you're not using a Bosch pump, you'll need a separate high-pressure check valve. Earl's has those.

Thanks! Good info.