How do you keep the air and petrol from separating?

not a problem with injection

_________________
the world is a book, and those who do not travel read only a page
66 Mini Minor sponsored by http://www.lifeonthehedge.com.au/ The Dog Harness Specialists
It was a pleasure ausmini. I'll miss all you misfits and reprobates

I've just had 2 goes at typing today's progress post and lost it all twice. Brain dead and going to bed.

Morris's question is a fair one if you look at the photo matt posted. The injectors are on the throttle bodies on the exhaust side so the fuel air would travel all the way over the head to the inlet side.

Mind you the distance isnt that far..

_________________
Cheers
Alec
1275LS - July 78 - XNFAD18Y/102918

Mokesta, what are you using there for throttle control- a slide throttle or butterflies? Won't work with full air and no throttle (it's not a diesel...)

_________________
DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

It is not the distance, it is the 180° corner.

Doc,

Look at the earlier pick with the transparent blue box around the inlet pipes. This plenum would have a stock MX5 throttle body on it. As mentioned above, I have a MSPNP Megasquirt for an MX5 in the shed, a full MX5 engine harness with sensors and crank angle sensor plus ignitors, throttle body etc. I am really hoping to inject the Pierce head for less than a grand for all of the set up then about 4 hours dyno time.

I just haven't drawn the plenum for the last layout yet. I have been distracted by too much going on at work and the spring yard clean-up. This will be much harder to make a box for the pipes that doesn't get in the way of the plug leads.

On the other thing, the set-up in Matt's photo would have bad manifold wetting but it wouldn't be a problem with port injection. I still don't like too tight a radius on the inlet. By my measurements any runners over the rocker cover would only be about 25mm inside diameter which I think may be a bit small for the length. But see my first post, that's just a hunch...

M

Mokesta was only ever discussing injection

_________________
the world is a book, and those who do not travel read only a page
66 Mini Minor sponsored by http://www.lifeonthehedge.com.au/ The Dog Harness Specialists
It was a pleasure ausmini. I'll miss all you misfits and reprobates

but Morris 1100 was continuing a joke about this:



The injectors are there on top of the throttle bodies at the other end of the pipes, not at the head end..

_________________
Cheers
Alec
1275LS - July 78 - XNFAD18Y/102918

I think they are carburettors, so no injectors anywhere in that photo.

Andrew

I have spent some time trying to make the injection work for a round nose. The problem is the plenum encasing the runners and the fuel rail hitting the bonnet and bonnet slam panel.

To try to make it better I have replaced the Bosch injectors with Denso ones that mount into the manifold differently. This enables a thinner manifold flange. I have also tried to compress up the runners. I know I can do better with these so I'm not pushing that area.

I have dropped the runners down where they meet the manifold so that they are not concentric with the ports. Since the ports are 40mm and the ID of the runners is 35mm I have dropped them down 5mm so that the bottom edges are tangent. That also helps with the injector relief needed in the head flange.

Even with the changes, the picture below shows the fuel rail very close to the bonnet profile. This profile is dodgy because I don't have an engine in a roundy to measure from but it is close enough to know that things aren't looking good. The profile of the bonnet is on the centre line so the dip is the cross-over of the inner ribs. The bonnet will be lower at each end of the fuel rail.



I have had a try to see if runners dropping straight down would allow horizontal injectors but as you can see they won't be any good either.



I think I'm going to have to either:
(1) look for short stumpy injectors,
(2) do a low-profile fuel rail,
(3) use flange mount injectors (as opposed to rai-retained) and mount them at 45 degress to vertical or
(4) mount the injectors under the runners where things are already crowded with the plugs and leads.

That layout shown with the runners going over the rocker cover isn't looking that silly after all...

This is where I'm at. Again, the plenum enclosing the runners and onto which the single throttle body mounts is not shown: Any ideas welcomed.





If anyone can give me the distance from the inner edge of the bonnet slam panel to the centre of the head studs as shown below, I'd really appreciate it.



M

Inject from the bottom? Or is that a flow no-no? Might also foul the alternator.

there are short EV6 Bosch injectors. could be short enough to give the needed clearance

_________________
Rover 214 atm ....

Thanks Klas, those EV6 injectors are 17mm shorter which would give a big clearance improvement. They mount the same as other Bosch so I'd have to use the other flange design suitable for 14mm O-rings to that would mean I 'd lose about 5mm. Still 12 overall may be enough.

M

how much room is there between the flange and the rocker cover. Ideally this is the place to put the injectors as they get a bit closer to the port. Drill at the right angle and you might have a bit more room for fuel rail.

Better yet, if you are going EFI, why use the weber flange at all?

You don't need them! Simply cut them off and come up with a better way to mount the inlet runners.

At the very least you can machine it pretty thin, make your inlets from CFRP to reduce the weight. Those flanges have been made to hang some pretty heavy manifold and carb harware.

<edit> machine off the weber flange and mount your inlet runners by drilling and tapping in the machined face on the head

_________________
the world is a book, and those who do not travel read only a page
66 Mini Minor sponsored by http://www.lifeonthehedge.com.au/ The Dog Harness Specialists
It was a pleasure ausmini. I'll miss all you misfits and reprobates