Fuel injector choice?

[sr2]

Hi guys, would appreciate some sagely advice from the ‘Oldschool Brains Trust’ on this one. In my never ending quest for ‘overly complicated solutions to automotive problems the never existed in the first place I’ve come up the following idea to inject my 208ci 9 port Holden 186 motor I’m building for my beloved Rigamortice.

https://oldschool.co.nz/index.php?/topic/49842-sr2%E2%80%99s-1947-vauxhall-%E2%80%9Crigamortice%E2%80%9D-build-thread/

My cunning plan is to fit a hidden fuel injector into the bodies of each of 3 H6 Su carbs I’ll run on the motor. In effect I’ll be repurposing the stripped our carbs as injected throttle bodies. Reality is I’d be lucky if I got 200hp out of the old lump so 3x 500cc injectors would more than suffice.

Question is.

1: What readily available (i.e. cheap 2^nd hand!) injectors could I use for the prototype?

2: How can I connect a fuel supply to them if I’m not running a conventional fuel rail as they will be hidden inside the carbs dome.

[Stu]

If budget conscious something like the 510 or 550cc evo injectors might be an option? High impedance and they have a good misting spray pattern.

[chris r]

Another option (if you don't want side drafts) is a falcon throttle body injection on a aftermarket manifold, can fit a stock style pancake filter on top. 

I started dreaming about that stuff for my 202 in the tonner. 

Another option I thought of would be the vl style fuel injectors with the hose tail, could extend the hose tail or barry up something to the carb body for the fuel supply 

[mjrstar]

I probably have some evo 560cc injectors for cheap, but would suggest flow test /clean. (Which might make then not cheap)

Bmw stuff runs stainless fuel rail which might be easily  or you can get blank aluminum fuel rail.

 

 

Just save the hassle and run the carbs.

 

[shrike]

You could probably get away with 410cc injectors, K24 factory injectors are plentiful and easy to source plus they are slightly newer then the evo ones 

My general rule of thumb for 6cylinders was 1hp per cc of injector for 6, so 410hp/2 is 205hp but if your planning on running e85 the evo ones are probably a better option 

[HighLUX]

Get some roman dave spec 3d printed fuel rails that will hide inside the SU and just run EFI rated fuel line between the 3 SU's to look factory enough

[Nominal]

Not sure where they come from but these systems sometimes use an injector 'cap', looks to be retained by a circlip

 

[shrike]

[Bearded Baldy]

I love the idea of hiding injectors in the carbs.

I have a set of 4g63 rvr yellow injectors here you can have if they are any use to you.

My longterm goal is jenvey heritage itbs. Think a DCOE webber but with injectors hiding in the fuel bowl.

[Muncie]

Put 6 in underside of manifold it won't quite be port injection due to Siamese ports but will be easier to get running right.

Use some holden Ecotec injectors.

 

[Doug Hill]

There's a chap in the Hawkes Bay car club who has done injectors in a set of SUs on an older Jag. I'm fairly sure the injectors are up the needle/jet hole from underneath. 

 

 

[sr2]

On 31/07/2025 at 08:43, chris r said:

Another option (if you don't want side drafts) is a falcon throttle body injection on a aftermarket manifold, can fit a stock style pancake filter on top. 

I started dreaming about that stuff for my 202 in the tonner. 

Another option I thought of would be the vl style fuel injectors with the hose tail, could extend the hose tail or barry up something to the carb body for the fuel supply 

Small world, I’ve actually got a Falcon throttle body I was thinking of using. They have the same stud pattern as the downdraft weber (I have a manifold to fit) and have the fuel regulator built in.

Have to say however I’ve got my heart set on the cool look of 3x SU carbs!

The VL hose tail injectors look good but as I’ll only be using 3 of them the 255 cc/min might be a little small. I’ve just discovered fuel injector hose tail adaptor’s so the fuel rail issue is sorted.

 https://raceworks.com.au/fuel/accessories/injector-upper-hose-tail-adapter/

[sr2]

On 31/07/2025 at 16:24, Nominal said:

Not sure where they come from but these systems sometimes use an injector 'cap', looks to be retained by a circlip

 

Yes I’ve seen their website – scary spendy!

I always thought you had to have the injector after the throttle butterfly, obviously you don’t. Opens up some interesting options.

[sr2]

On 05/08/2025 at 10:38, Muncie said:

Put 6 in underside of manifold it won't quite be port injection due to Siamese ports but will be easier to get running right.

Use some holden Ecotec injectors.

 

That was my original idea but with the Holden 6 not being crossflow the exhaust/headers would be in the way of the fuel rail.

[sr2]

On 05/08/2025 at 12:11, Doug Hill said:

There's a chap in the Hawkes Bay car club who has done injectors in a set of SUs on an older Jag. I'm fairly sure the injectors are up the needle/jet hole from underneath. 

 

 

I found these Jag injection conversion pictures on an Aussie site from 2002.

 

 

[chris r]

1 hour ago, sr2 said:

Small world, I’ve actually got a Falcon throttle body I was thinking of using. They have the same stud pattern as the downdraft weber.

Not the same as the 34 adm as I found out, just different enough not to work 

 

But I agree, 3x su carbs look so much better 

[chris r]

1 hour ago, sr2 said:

I found these Jag injection conversion pictures on an Aussie site from 2002.

 

 

I've got a couple of spare falcon tbi (side feed) injectors if you wanted to have a go at making them fit into a su body 

[kws]

The Patton Machine setup looks real tidy, albeit not as hidden as some others as it removes the dashpot.

https://fiddlingwithzcars.wordpress.com/fuel-injection-patton-machine/