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Port Injection?


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#1 RooBoonix

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Posted 19 November 2020 - 10:39 PM

Hi guys

 

I've just bought an Eaton M45 which is going to extend my already extended project, but hey ho.

 

I see most solutions for fitting a supercharger seem to be suck through, but are there any projects about where someone has successfully implemented port injection? 

 

Some people say suck through can affect the "coatings" in the supercharger, others have no problems, I'm not overly concerned about that. I'm more thinking that port injection may be beneficial from a power and efficiency point of view. I'm just brainstorming, if all else fails I'll just run a throttle body.

 

 

Cheers



#2 Tupers

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Posted 19 November 2020 - 11:33 PM

You should go an check out the Turbo Minis forum.

There are multiple people on there who have built port injection manifolds for turbo engines and it’s all the same for supercharged or naturally aspirated Minis for that matter.

#3 RooBoonix

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Posted 20 November 2020 - 12:04 AM

You should go an check out the Turbo Minis forum.

There are multiple people on there who have built port injection manifolds for turbo engines and it’s all the same for supercharged or naturally aspirated Minis for that matter.


Thank you I'll check it out

#4 mini13

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Posted 20 November 2020 - 08:55 AM

word of warning,

 

port injection is pretty complex due to the siamese ports in the mini head, due to this the mixture gets skewed between inner and outer cylinders, i seem to remember seeing figures of 1-1.5 AFR difference, which is pretty big especially on a turboed motor.

 

IIRC on turbomini's they were using a pair of lambda sensors ( one for inner cylinders one for outer)  sampling pre turbo ( meaning you need a bunch of extra pipework so the sensor dosent see exhaust pressure) then injector timing was being mapped though out the rev range to counter the skewed AFR's

 

It all sounded a PITA to me so i used a 7 port head to get around the issue.



#5 RooBoonix

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Posted 20 November 2020 - 09:03 AM

word of warning,

 

port injection is pretty complex due to the siamese ports in the mini head, due to this the mixture gets skewed between inner and outer cylinders, i seem to remember seeing figures of 1-1.5 AFR difference, which is pretty big especially on a turboed motor.

 

IIRC on turbomini's they were using a pair of lambda sensors ( one for inner cylinders one for outer)  sampling pre turbo ( meaning you need a bunch of extra pipework so the sensor dosent see exhaust pressure) then injector timing was being mapped though out the rev range to counter the skewed AFR's

 

It all sounded a PITA to me so i used a 7 port head to get around the issue.

 

I wondered if that may be the case, I didn't know if I managed to get the injectors far enough away from the head that it may negate the effects of the siamese ports. Ie: injecting fuel at the bulkhead end of the intake manifold so there is 6" or so of port before they split to the inner and outer cylinders.

 

It's all down to limited space I guess and managing to fit the injectors in around the supercharger, it may be more effort than it's worth.. 

 

Of course like you say a 7 port head solves the issues, but they aren't cheap!


Edited by RooBoonix, 20 November 2020 - 09:03 AM.


#6 mini13

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Posted 20 November 2020 - 09:35 AM

pretty good results have been  seen using a " wet maniifold" setup although this normally comprises of a normal manifold with a single throttle with injectors in and boost going through that, but as long as your injecting into a central point that both runners draw from, it should workl ok.

 

another thing is with the port injection you need an ECU that can cope with being able to adjust the injector timing, with the wet manifold there are obviosly much more options.



#7 RooBoonix

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Posted 20 November 2020 - 10:49 AM

pretty good results have been  seen using a " wet maniifold" setup although this normally comprises of a normal manifold with a single throttle with injectors in and boost going through that, but as long as your injecting into a central point that both runners draw from, it should workl ok.

 

another thing is with the port injection you need an ECU that can cope with being able to adjust the injector timing, with the wet manifold there are obviosly much more options.

Looks like wet manifold should be my point of research then.



#8 Ethel

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Posted 20 November 2020 - 02:08 PM

It'll be down to time, effort & money - as usual.

 

There's a credible theory that the A Series prefers carbs because they provide a coarser fuel/air mix that  biases opposite to the Siamese ports. Of coarse , fuel injection still has a big advantage in giving more accurate & responsive control.

 

Since the Siamese ports are unalike, the optimum likely isn't for the cylinders they feed to get matching AFR anyway.



#9 RooBoonix

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Posted 21 November 2020 - 06:52 PM

It'll be down to time, effort & money - as usual.

 

There's a credible theory that the A Series prefers carbs because they provide a coarser fuel/air mix that  biases opposite to the Siamese ports. Of coarse , fuel injection still has a big advantage in giving more accurate & responsive control.

 

Since the Siamese ports are unalike, the optimum likely isn't for the cylinders they feed to get matching AFR anyway.

 

I think I'm going to have to make a false bulkhead and get an idea of the sort of space I have to work with, and see if I think I'll be able to make a manifold that can a) fit injector(s) where I want and b) still flow how I want it to. 

 

Lots of research and tinkering needed.



#10 mini13

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Posted 22 November 2020 - 12:37 PM

Are you dead set on the charger position? if the charger was moved to the front of the engine it would mean you could use a much simpler setup for the injection like on a turbo motor.

 

Ive seen somwhere, K series (MGF) throttles with a pair of injectors bonded in bolted to a std style manifold, much like the Specialist components setup. If I were approaching this I would look at doing this, possibly using a Maestro manifold with the long runners (think Ive got a pic will take a look).

Attached Files


Edited by mini13, 22 November 2020 - 12:40 PM.


#11 RooBoonix

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Posted 22 November 2020 - 12:48 PM

Are you dead set on the charger position? if the charger was moved to the front of the engine it would mean you could use a much simpler setup for the injection like on a turbo motor.

Ive seen somwhere, K series (MGF) throttles with a pair of injectors bonded in bolted to a std style manifold, much like the Specialist components setup. If I were approaching this I would look at doing this, possibly using a Maestro manifold with the long runners (think Ive got a pic will take a look).


I've made no plans yet, I've just bought the supercharger and need to rebuild it. Although I hadnt really considered moving the SC to the front of the engine it's something I'll bear in mind. I'd like to keep it to the back really but thanks for the photo and potential inspiration

#12 timmy850

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Posted 24 November 2020 - 11:36 AM

The Mighty Car Mods mini (1275 with vmax supercharger and injection) was changed to be port injected - but there aren't any details of what they did unfortunately. 

 

About 2:20 in this video he mentions it

 

Some of the tuning stuff is here

 



#13 Steve220

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Posted 24 November 2020 - 12:40 PM

The Mighty Car Mods mini (1275 with vmax supercharger and injection) was changed to be port injected - but there aren't any details of what they did unfortunately.

About 2:20 in this video he mentions it


Some of the tuning stuff is here


They moved them to under the charger to wet manifold, however it didn't work. Moog's biggest issue was he was running standard compression ratio and trying to fuel it correctly. It wasn't making the power without knocking.


Edited by Steve220, 24 November 2020 - 04:18 PM.


#14 RooBoonix

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Posted 24 November 2020 - 02:38 PM

 

The Mighty Car Mods mini (1275 with vmax supercharger and injection) was changed to be port injected - but there aren't any details of what they did unfortunately.

About 2:20 in this video he mentions it


Some of the tuning stuff is here


They moved them to under the charger to wet manifold, however it didn't work. Moog's biggest issue is he was running standard compression ratio bans trying to fuel it correctly. It wasn't making the power without knocking.

 

 

This is kinda what I'm thinking of doing, trying to put 1 injector per "runner" as far away from the head as practically possible (as previously mentioned I've gotta do some mock ups). Still struggling to find many people who have done this and photographed their manifolds...

 

I've seen a few where people are injecting with 2 injectors at a single point farther away from the head but I don't see the benefit of this compared to 1 injector per "side", I'm still very early stages so I'll keep researching.



#15 mini13

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Posted 24 November 2020 - 03:11 PM

https://www.starchak.ca/

 






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