RB20 injector dillema

[omp]

How's it? I have myself an RB20DET, It has FMIC, T04/T3 turbo, LTx12 microtech, Bosch 040, Malpassi rising rate fuel reg. Now the dillema I am facing is that I have Rx7 non turbo injectors fitted (460cc). The tuner had to run the car rich at idle due to dropping the cycle 1msec caused the car to hesitate and hunt. This is what he told me. This is causing problems, shitty fuel consumption as 90% of my driving is fairly local and the excess fuel seems to be washing the bores. The RB has been rebuilt and I think the overfueling is causing more damage than good. The tuner recommends that I drop injector size, so I have got my hands on a set of CA injectors to fit as they about halfway between stock (RB20DET) and what I have now. I am afetr opinions should I 1/Get him to try again with the 460cc's? or 2/Get the CA injectors cleaned and flow tested and fitted/tuned? What do you think? The tuner is fairly well respected as he has the Ford (hahaha) performance contract doing the new turbo falcons and v8's. Thanks for your opinions Pete

[blind_elk]

What fuel pressure are you running? You could possibly back off the pressure a bit via the Malpassi. Cheaper than getting more injectors.

[omp]

I was told the fuel pressure is 50psi... I was told the series 4 turbo injectors were a prick to tune, the series 5 being better. Maybe the same for the non turbo's.....Perhaps I shoulda just got GTR injectors, but will see how the CA ones go.

[jnr32r]

im not too sure about the non turbo rx7 inj, but i have series 5 turbo and dont have any probs, so i cant see why he cant tune them? I dont know much about mirotechs but you should be able to tune them. Are they high impendance inj?

[omp]

They are low resistance injectors. What is your fuel consumpton? I get 150km's to half a tank local driving, Best I have gotten is 350km's from full down to 1/3 that was highway driving, so the cruise is fine just the bloody idle and low rpm!

[mist]

hi OMP,

don't know if u saw my reply in the other thread where u posted, so here goes -

i'm running 550cc injectors on my RB20, ECU is AP Engineering PFC. Injectors have gone up just over 100%, but my tuner has done an awesome job with the staging, idle, etc - tuning work. Running a HKS GT2530 turbo, and I only run around 1 bar of boost so we're probably talking about a similar power range, tho I'm probably making less power heheh. I don't think the injector size is too big - my 550cc injectors are bigger than yours and with careful tuning, I even have excellent fuel economy on highway (230kms on just half a tank) and acceptable town consumption - 250-350kms. perhaps there is some issue with the specific injector itself? lag time or something? I don't know much about injectors

[jnr32r]

i have the same setup as mist except for a 2535, and about the same consumption. Thats with relaxed driving, the moment you start driving hard consumption drops dramatically, id say about half.

hey mist what sort of power are you making?

[mist]

no idea mate

car was road tuned and also tuned on circuit, so i have honestly no idea what power the car's making. have awesome on-off response and the car pulls like a train to my limit of 8000rpm tho...

[Chris32]

How's it? I have myself an RB20DET, It has FMIC, T04/T3 turbo, LTx12 microtech, Bosch 040, Malpassi rising rate fuel reg. Now the dillema I am facing is that I have Rx7 non turbo injectors fitted (460cc). The tuner had to run the car rich at idle due to dropping the cycle 1msec caused the car to hesitate and hunt. This is what he told me. This is causing problems, shitty fuel consumption as 90% of my driving is fairly local and the excess fuel seems to be washing the bores. The RB has been rebuilt and I think the overfueling is causing more damage than good. The tuner recommends that I drop injector size, so I have got my hands on a set of CA injectors to fit as they about halfway between stock (RB20DET) and what I have now. I am afetr opinions should I 1/Get him to try again with the 460cc's? or 2/Get the CA injectors cleaned and flow tested and fitted/tuned? What do you think? The tuner is fairly well respected as he has the Ford (hahaha) performance contract doing the new turbo falcons and v8's. Thanks for your opinions Pete

Whats the Microtech like? I am saving for one of these at the moment, and will be running a similar setup, but with GTR cams, exhaust manifold and GTR injectors

I am going to get the LT-12S though, but interested to hear what your experiences are

Chris

P.S - from every big injector/programmable computer setup I have ever seen with Idle/low speed problems, it always comes back to the tuner. Was it tuned via hand controller or via Laptop? Freebaggin has a LT-12 in his R33, running 280rwkw, and has just recently had a retune utilising the Matrix mode tune, and from all reports it drives really well now, maybe PM him

[blind_elk]

I was told the fuel pressure is 50psi...

That's maybe a bit high (3.5 bar), most injectors usually run around 38 - 40 psi (2.7 - 2.9 bar).

[omp]

Doesn't matter, my rebuilt RB20 has 2-3mm end play on the crank. The engine rebuilder is refusing to touch it. injectors are the least of my worries now...

[predator]

yeah.. old rb20det's are problems.. sounds like it was rebuilt pretty badly - that was probably the problem in the first place.

[V8eta]

Yeah, im running 450's from a 4g63 in my rb20 with a link and im having no issues with idle and fuel economy isnt to bad when cruising so i doubt it is your injector size causing the problems.

[WHITE R32]

ill tell you what wont help.... i was going to use some rotary injectors in my rb20 untill i realised a major factor.... rotors love fuel... the more u give em they just keep going .... any rotor injector had basically no or just a really crappy spray pattern.....therefore they arent really suited to a piston engine.... so i went for gtr injectors myself and the 4g63 are another good option.....im not saying u made a bad decision but what i am saying is that it makes it harder to tune idle/low revs and also i use about 35 psu fuel pressure thats about all u need...... get everything else sorted dude then maybe try amd gtr or similar injectors....this is just the opinion i have formed after listening to several ppl in the know and trial and error im not saying im 100% correct...9but i hope i am )

[omp]

Thanks for the advice. But after what I have put up with in the last year with faulty workmanship, after it is fixed I will be selling the car....... no more performance, just not worth it anymore.