EFI Systems - Page 4

robcf · 02-06-2016, 04:03 AM

Glad to hear its moving along.

The P&G sensors are very expensive, however, they are easy to package. Did you consider a common magneti marelli sensor?
Throttle Position : TPS PF2C Magneti Marelli - Jenvey Dynamics

I also noticed there is only one idle stop screw.

chris_seven · 02-06-2016, 07:59 AM

Rob,

We only need one idle stop screw - there is a balance adjuster on each the linkages that join the individual shafts. It is equivalent to what is commonly referred to as an 'ALFA lever'.

In this way we can use the standard crossbar from a Weber Carb set up and balance in a reasonably straightforward manner.

We hadn't considered a Marelli TPS and I realise that the P&G sensor is expensive and is why we aren't going to use them.

We are using a non-contacting Hall Effect TPS from Variohm. They are a UK based company that are quite local and I have worked with them many large capital projects over a number of years and am confident in their capability.

We will use the sensor with a 32mm PCD which fits quite well.

Euro XPD D-Shaft Non- Contacting Rotary Position Sensor by Variohm from Variohm EuroSensor

robcf · 02-06-2016, 01:15 PM

For some reason I like to see idle adjusters on each throttle (or each common shaft), however, your design will work fine. You will be able to set the idle, balance each valve ect.

I've not see the Variohm sensor, I presumed it was P&G due to the packaging space which appears to be much the same. Could you share the retail price for one of these Variohm tps?

Looking forward to seeing the first castings.

rgruppey · 02-21-2016, 12:53 AM

Hi Chris,

How is the development of your itb's progressing? For those of us looking for an efi solution with the old school aesthetics, a highly developed system in a straight out of the box application would be an enticing prospect and I am sure would fill a definite gap in the market. Particularly for those of us based in the uk.

Please keep us posted. Cheers Sean

chris_seven · 02-21-2016, 04:30 AM

Patterns are virtually finished.

We just drawing a 'Billet' Distributor that can be used with a Twin Plug set up and retain the classic appearance.

By installing a trigger wheel into the distributor body we can also sense the cam position.

Ferrino · Ferrino's Garage

Really interested in your fuel injector plumbing, as depicted in your CAD snapshot below. Putting together my own Suzuki-based budget EFI system right now and am torn between using a conventional rail, versus individually-plumbed MFI-style injectors. I love the look of those big looping polyamid/nylon lines, but it also avoids any misalignment issues with a rail for the DIY-er. Are you putting an NPT thread at the top of the injectors? What type of hose/fittings will you be using?

I was thinking of using something like these holders, which seem slightly different from your design, where the "cap" is bolted to the runners and not the bung/base:

chris_seven · 03-06-2016, 11:15 PM

We looked at something similar but making the boss on the injector seemed too costly and needed too much machining.

We have drawn up a fitting that we will use with a PTFE hose so we can use an outer crimp rather than a press fit hose tail.

ATEC in the UK provided us with a hose tail drawing which we have adapted so we can make a suitable fitting to crimp to the hose.

We are making a small batch in Stainless Steel.

They will hold an O Ring so that they will fit a Bosch Motorsport injector in the same way as a fuel rail.

chris_seven · 05-11-2016, 08:29 AM

As I posted on another thread the 100mm tall intake manifolds that we have cast are ready.

These have the same spacing as a Weber 40IDA3C and are replicas of the 911R Intakes as we have an interest in reproducing these parts.

We are initially sand casting these manifolds in Magnesium (AZ91) and may eventually make some in Aluminium to save money.

The patterns will me mounted into a frame and a running system fitted to the board.

It was our original intention to fit sand cast the throttle bodies and to make conventional patterns bit we have had a change of direction.

We have made basic patterns using a 3-D Printer and added shrinkages allowances to our CAD Model.

We dressed the patterns slightly and then painted them to smooth the surface and produced Silicon Rubber moulds to allow them to be Investment Cast.

We are finishing the ID with a steel bar and we have made the first wax impressions and casting will be ready and heat treated early next week.