Injector Setup

[roba]

Im using top feed injectors in a rb25det (side rail) inlet plenum.

Ive had a few problems making power and im chasing up any potential issues.

http://www.skylinesaustralia.com/forums/Rb...l=missing+100kw

One that has come up is the injectors dont sit deep enough into the flow causing inefective atomisation.

Has anyone else come accross this?

Please post pic of yr setup.

cheers rob.

[R34GTFOUR]

why dont you sell the top feed, then buy some side feed injectors that are suited to your rail. Problem solved?

[r33_racer]

or get a top feed rail to suit the injectors?

Im curious how you fitted top feed injectors into a side feed rail? You must have modified the crap out of the rail?!?!

[Craved]

or get a top feed rail to suit the injectors?

Im curious how you fitted top feed injectors into a side feed rail? You must have modified the crap out of the rail?!?!

he didnt, pic from his other thread - top feed rail.

http://www.skylinesaustralia.com/forums/in...t&id=144591

i dont think that the injectors being set back into the open in each runner would cost you 100kw from low atomisation.

[roba]

http://www.skylinesaustralia.com/forums/in...t&id=144591

i dont think that the injectors being set back into the open in each runner would cost you 100kw from low atomisation.

Chasing up any and all possiblites at this stage...

If injectors spraying onto the walls and dribbling into the cyclinders then I would assume that would make a huge differance to combustion???

why dont you sell the top feed, then buy some side feed injectors that are suited to your rail. Problem solved?

Looking into it... but will have to find injectors and plugs, and new fuel rail then modify to suit my fuel system etc

will be easier and cheaper to mount mine a little better. just after a few ideas on how other people have done it...

cheers rob

Edited May 21, 2008 by roba

[Craved]

Roba - you know how far in teh injectors sit into the runners?

i did see a post with pics regarding the injectors and how far recessed they are from the air path.

your looking at up to 60psi of rail pressure, unless you injectors arent pointing directly into the air stream i dont see how it would dripple down to the inlet valves.

have you checked that the injectors are perpendicular to the injector hole face?

[Dahtone Racing]

we've got SARD top feeds going into an RB25DET plenum

we're using TUFRX3s converter seals, hes had people testing em with no problems

ill keep you updated with how we go with em

[fletch rb30]

Im running rx7 550cc top feeds in a side feed manifold. You need to get an 18.5mm (what i had on hand) drill bit and drill out the holes for the injectors.

From memory i nearly drilled right through, it does not matter if you do tho. Then you can push the injector further into the manifold. the stock o-rings will not fall in as they are like 30mm. With the manifold off you can see the pintle of the injector is just sticking out a mm or 2 into the flow.

I did this after i saw a mate with same setup as yours, under boost the o-rings were moving up the bottom of the injectors and i thought there was potential for fuel and boost to leak

[xsv_32]

Im using the rb25de intake and have top feed gtst rail (r32) and top feed injectors but they dont want to fit into the rail as the o ring seems to fat. Can i replace the o rings or does it just take a lot of work to squeeze them in there? The 25de ones pull straight out relatively easily though...... any advice??????

[fletch rb30]

put the 25de o-rings on the new injectors. Or buy some new o-rings from nissan, i have rx7 550cc and with rb20 o-rings on them they are still really tight in the rb20 rail. I lubed them up a little with a little bit of new engine oil and made sure i didnt pinch the o-rings when i out them into the rail.

Once they are in, you can pressurise the rail to 60psi and they wont fall out!

[xsv_32]

Awesome, il give that a go tonight.

[xsv_32]

Um no good, tried swapping the injector o rings but they still wont fit at the rail or the plenum.

May have to sell and buy something else. Any suggestions or offers for replacement injectors?

The current ones are 670cc's so nothin smaller than 650 i suppose. Have to be top feed.

[Dahtone Racing]

what brand of injectors are you using?

the stock rail has a 10.5mm hole but some injectors require 11mm hole in the rail

[xsv_32]

yeah they must be they are only a fraction too big. Could i get the fuel rail and runners machined to fit them or is it better to just get different injectors. Had a look on trademe and the other sard injectors to suit gtrs have 14mm o rings top and bottom.....

Anyone who has top mount injectors to fit 20det/25de intake setup around the 6/700cc mark for sale please message me.

[Dahtone Racing]

id just machine the rail half a mm