5 replies to this topic

[mrbrightside]

Apologies if this topic has been covered, a search produced unrelated MPI topics!

 

I've been looking into this subject with the intent of using a single Jenvey DCOE based twin throttle body and Omex management.

 

 

An initial chat with Omex resulted in them not being confident it could be done due to cylinder robbing, but i don't think i spoke to the organ grinder, i'm hoping to speak to him on friday. Have any of you guys ever done this type of conversion before?

 

PS. Thanks for the help on my first thread about my inlet manifold. I'm on a bespoke made 150mm ally one over the exhaust now and am up to 88bhp with improved pickup.

 

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[mini93]

It is possible to fuel inject the A-series away from the standard MPI arrangment, but as the guy from OMEX said, its no simple job. The work around from the port robbing is setting up sequential injection with accuratly times injectors. There's a few people on Turbo Minis forum who have delved deep into this, and posted a lot of the information out there for you to soak up, and its something I'm hoping to go for in my current project. From what I read it's no cake walk.

[mrbrightside]

It is possible to fuel inject the A-series away from the standard MPI arrangment, but as the guy from OMEX said, its no simple job. The work around from the port robbing is setting up sequential injection with accuratly times injectors. There's a few people on Turbo Minis forum who have delved deep into this, and posted a lot of the information out there for you to soak up, and its something I'm hoping to go for in my current project. From what I read it's no cake walk.

When you say the standard MPI arrangement, do you mean a single throttle body with twin injectors?

[mini93]

Yes. although not really being upto speed with the MPI set up, I dont know the system very well at all. Just from what I have read elsewhere, people using custom manifolds, megasquirt ect ect have had successful results

[Steve220]

Biggest issue is timing the Siamese injector pulses. i looked into turboing the standard set up but the research and results are in their early days and there are other options out there.

[mrbrightside]

I spoke to Omex's expert today, he says they themselves tried and couldn't get a setup that had significant advantages over a carb. It really needs to be one squirt from a big injector at high pressure on the piston downstroke, any earlier and the fuel pools. This led to timing problems which they were unable to effectively overcome. The other option they tried was with a single throttle body and multiple injectors, but all they ended up with was something fairly similar to a carb in operation and fuel delivery. They told me they are aware of a lot of companies that claim to be able to make it work, but they seriously doubt the huge amounts of effort involved would amount to a workable and cost effective system. They were involved in a motorsport project on an Austin Mini back in the 90s some time which had fuel injection, they tell me they did no better in the end than if it had been on carbs due to the problems being mechanically based not electronically based.