Inlet Manifold Design
Turbo Mini Forums

Right, I've got a problem with this design.

I've ended up with the exhaust manifold branches a bit higher than I would have liked. This means that I can't get two injector inline on the inlet tract. It's more like the mirage setup.

The best design that will fit under the bonnet is as the attached .pdf.

The only way I can fit two injectors in is with one injector as shown and the second in either position A or B.

Any preferences?

Attachments:

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Edited by Paul S on 14th May, 2007.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

What about shortening tube length, and having the plenum sit further back...

That should free more space up top ?

And perhaps switching to the shorter "pico" style injectors ?

9.85 @ 145mph
202mph standing mile
speed didn't kill me, but taxation probably will

Can you not sit them next to each other in the same tract, just rotated round a bit if you get my drift?

So that you have 2 in the posistion you have marked in the drawing..

Forgive me if its a stupid idea, I know didly squat about injection

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

id junk the a and b positions and stick them in the plenum facing the bellmouths axel !

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

oh but make sure those are the high rpm second stage .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

as t2 mentioned, can two not be fitted side by side parallel or angled to fire on the back of the opposite valve head - much better idea than Aor B - if you do the side by side type at least the distances from the valve to the injectore will be the same if that makes sense. You should be able to do an elongated section of manifold to site the two bosses into.

If Carling made Mini engines
it would probably be like this one!

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

run the theoretical airspeed axel ,and see how fast its moving at the rpm's your talking about ..i think itll work , but if it didnt you could allways double bung the manifold for a testing option on both .?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

I'll have to think it over a bit more but to have a real shot (no pun intended) at firing into the open valve period would be to have the injector close to the valve ..... otherwise you'd have to fire early to counter the transit delays and thus would almost certainly be firing into a unstable / reversing airstream thus, to some degree, running into the charge robbing issue.

I might have that wrong, tird and hungry but hat is how it seems to me as I tyre this.

Every day is a school day ...........

How fast and how expensive ...... the same question...

Hi,
I'd be intereseted to find out what the timing implications would be for second stage a fair way from the valve as that'll probably be how mine will be done....
Cheers,
Gavin :)

Edited by Bat on 14th May, 2007.

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A friend here in Norway has allegedly got 250 hp from a 1293 turbomini using a normal autronic system. He has made his own inlet with two pipes going side by side before merging into one close to the inlet to the head. He has placed the injector that is feeding cyl1 in the runner opposite of cyl1, and the injector feeding cyl2 opposite (or further away from) cyl2 and so one. Seems to work for him...

Edited by miniminor63 on 14th May, 2007.

Is that Brede Alnes of TS Racing?

This is taken from the latest Minimag:

Edited by Paul S on 14th May, 2007.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

correct! if you could scan that article it would be nice. we cant get minimag over here!

Edited by miniminor63 on 14th May, 2007.

If it were me I would use position B. This seems to be the best compromise for being close to the valve for good timing and having a straight shot at the valves for less wall wetting.

As for the setup above, I'd be curious to know how driveability is for the entire range and how fuel efficient it is. I think you can probably optimise a setup with a conventional ECU to generate a lot of bananas but I doubt you can do it well from low to high RPM/load.

I'd also be interested to see the actual angle of the injectors and how close they are to a plenum. It might actually be emulating a wet intake such as a TBI setup.

Jean

http://www.jbperf.com/

One thing I should add is that with position B, you'd want to have a good heat shield to make sure the injectors don't get heated too much by the exhaust especially if they're the staged ones which will only be used part of the time

Jean

http://www.jbperf.com/

I'm drunk and can't be assed to read all this, sorry folks!! bbut i would deffo go with position B unless you can fit 2 injectors side by side inthe primary position.

yep id say bredes is wet part of the time ,then as velocity increases prob works fairly dry ..
id made an assumption axel , that was that the inj point of opening would be advancing like a spark timing map ,and that it would be separately adjustable on each injector .did i get this wrong ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

By the way, the position B hits the bulkhead, so I'm looking at other options.

Saul Bellow - "A great deal of intelligence can be invested in ignorance when the need for illusion is deep."
Stephen Hawking - "The greatest enemy of knowledge is not ignorance, it is the illusion of knowledge."

Yes the injection timing is set using a map similar to a spark timing map. And the timing can be set with respect to the start, middle, or end of the injection pulse.

What that means is this. For example, lets say the injection pulse for the rpm/load is 5ms and the timing from the table is 30 degrees ATDC. Then for end-of-pulse timing, the injection will start 5ms before the engine reaches 30 degrees and stop at 30 degrees. For start-of-pulse timing, the injection will start at 30 degrees and last 5ms. For mid-pulse timing, the injection will start 2.5ms before 30 degrees and last 5ms so will end 2.5ms after 30 degrees.

Of course that's just an example and you would not use the same timing value for all three possible injection timing references. They each have there advantages and have been put in the code to see which gives an easier tuning of the injection timing which may also depend on the setup (intake size/shape, injector position,...). By the way, it's also possible to set the timing to a single fixed value for the whole range.

Jean

http://www.jbperf.com/

so as airspeed increases ,the point of injection onset can be mapped ,

and then fine tuned with the end,mid and start designation ,

so axel could run his lower inj at start of pulse setting ,
and then the upper ones at end of pulse ..or mid pulse ,
to get it all there at the same time

without having to run 2 sets of timings on the map ..

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

It might work but the code at the moment only has one set of parameters for both set of injectors (primary and secondary): one timing map and one timing reference (start, mid, end of pulse).

Also, the way the injector staging is done, is that both sets of injectors are injecting when the staging threshold is reached. The pulse width is reduced on the primary and the secondary is brought in.

That's another reason to have both sets of injectors close to each other. That could be changed in later releases but I'm still not convinced timing and wall wetting would not be an issue with injectors higher up the intake.

Jean

http://www.jbperf.com/

Yep - also the closer the injector is to the valve, the less change in injector advance needed wrt rpm as you're reducing / eliminating the time factor.