Injector advice

[Dean_mc88]

Sorry if this has been covered before but I couldn't find it.

I've just rebuilt my engine and bought myself a stand alone, however I'll be running a hybrid CT9 turbo externally gated. Will the standard injectors be fine or can I use slightly bigger injectors ? I know when you normally run a CT9 hybrid standard injectors are fine but with the stand alone having better mapping options would I benefit from uprated ones?

Spec is:

Wiseco Forged Pistons

Scat rods

Fresh rebuilt head

Hybrid ct9

Tial wastegate

Wolf v4x stand alone

custom route front mount

Stainless exhaust system

Lightened fly

Stage 4 clutch

Cusco LSD

[Gainzy]

Stock injectors will be fine

[Dean_mc88]

I thought so, I've just not read anywhere of someone running a stand alone on a ct9 hybrid

[Gainzy]

When are you getting it mapped, it'seems a serious ecu for a hybrid set up, what boost pressure are you going for? Duty cycle maxed of the stock injectors is 1.1 bar anything else is just daft I'm on no real gainshame to be made

[richardc9052]

Thats incorrect. The injectors wont necessarily be maxed at 1.1. It depends on fuel required. Ct9 at 1.0 vs td04 at 1.0 is completely different. So on a hybrid it depends.

The person mapping it will let you know if your maxed out. If you want to make sure that won't happen there are injector size calculators based on hp goal, engine size etc etc

[richardc9052]

Plus I doubt there are any graphs for the hybrid so the tuner may find power up to 1.3 bar. It all depends on the turbos capability

[Dean_mc88]

I'll be getting it mapped once I've ran the engine in. It's already got an emanage blue.

Yea it's a serious ecu but id rather have the best set up I can for the engine. I'm not chasing huge figures rather making the best set up for the ct9. I'm sure when I get it mapped I'll find out.

[richardc9052]

Have a look at the leaderboard. See the highest power ct9 hybrid. Check calculator for injector size based on that power at 75% duty @2.9bar rail pressure and thats what you need

[Dean_mc88]

Cheers will do

[Dean_mc88]

Using that calculator it says to use 362cc injectors that's based on the highest hp on the leaderboard at 207hp

[AdamB]

That will be due to the duty cycle, a lot of tuners will take injector cycle to about 94%.

It all comes down to how competent the tuner is.

[Dean_mc88]

I was reading up on injectors and duty cycle and they say a lot of injectors especially in highly modified cars are at there best at 70% so why would you nearly max out an injector if it isn't running efficiently ?

Is there other factors to take into account ?

I was reading up on injectors and duty cycle and they say a lot of injectors especially in highly modified cars are at there best at 70% so why would you nearly max out an injector if it isn't running efficiently ?

Is there other factors to take into account ?

[richardc9052]

Based on that id go for something like 400cc incase you make more power being forged the mapper will be able to push it a bit more.

I also dont see the point in running injectors at that high a duty cycle. There is a high risk of failure for no reason. injectors are cheap, engines are not.

[Gainzy]

Everybody knows the ct9 is maxed out after 1 bar 1.1 at a total push otherwise your just making too much heat no matter what the injector. I'd like to think a hybrid could do a 250hp mark with supporting mods it's possible. Let me know how you get on

[richardc9052]

Everybody knows the ct9 is maxed out after 1 bar 1.1 at a total push otherwise your just making too much heat no matter what the injector. I'd like to think a hybrid could do a 250hp mark with supporting mods it's possible. Let me know how you get on

Ive seen hybrids making power at 1.2 bar on standard internals, det was stopping them being able to turn boost up. With 6cc dished pistons that will clear up det and I bet theres still power at 1.3bar. Deffo about 250 to be made from a good setup especially with a wolf standalone and a competent tuner.

A standard ct9, I wouldn't even bother going past 1.0..

[Dean_mc88]

Everybody knows the ct9 is maxed out after 1 bar 1.1 at a total push otherwise your just making too much heat no matter what the injector. I'd like to think a hybrid could do a 250hp mark with supporting mods it's possible. Let me know how you get on

Yea I've not seen anyone push near 250hp on a ct9 hybrid. And I agree the ct9 would get hot like you said, I'm just looking for efficiency so pushing the standard injectors to the max to me doesn't seem efficient. If I can use injectors more suited and running more efficiently then your looking at constant reliable power right the way through the range.

I could be completely wrong in what I'm saying but using 380cc injectors at 70% surly is better than using standard injectors at 95% ?

Not that it should make a world of difference but I do possibly intend to use methanol as well

[Gainzy]

Well you could order some bigger one's set them aside on the day and if you are happy with how it performs send them back? But I think what you need for this build imo is just a healthy one bar set up.. that's going to be the efficient enough it's a fine balance between chasing power and just getting a happy set up for your money I've read people running 1.2 bar on them to Richard but some don't even make more power than the 1 bar set ups. It's just the luck on the day everyone's at different figure coming on here confuse's things ha

Edited July 17, 2016 by Gainzy

[richardc9052]

Just pulled this off the leaderboard.

[richardc9052]

The only forged running ct9.

[Dean_mc88]

Yea I've looked into that apparently it wasn't actually a ct9 and was running all sorts can't specifically remember what it was running though

[Gainzy]

Wonder if that's stock cams to..be cool to make the 250 mark on a ct9 be super quick on the corners and straight just not top end but who care's ha

[AdamB]

I was reading up on injectors and duty cycle and they say a lot of injectors especially in highly modified cars are at there best at 70% so why would you nearly max out an injector if it isn't running efficiently ?

Is there other factors to take into account ?

I was reading up on injectors and duty cycle and they say a lot of injectors especially in highly modified cars are at there best at 70% so why would you nearly max out an injector if it isn't running efficiently ?

Is there other factors to take into account ?

Define "at their best"?

You have to factor in fuel pressure also.

Fuel pressure too low and all you get is a dribble out the nozzle. Fuel pressure too high and the injectors become uncontrollable. Never drop fuel pressure below 2 bar, and never go over 6 bar.

You have to bare in mind, how often is the injector going to see 90% + duty cycle? Is it a track car where it's going to be at high / maximum load all the time?

A road car will very rarely see high injector duty cycles, hence why a competent tuner will use the duty cycle to their advantage, it saves the customer spending £500 on a set of ID 1000's or whatever.

Risk of running high duty cycle is increased heat, potentially burn the injector out. I've seen injectors at 100% duty cycle with no issues. It saves you a lot of money for something that's never going to be taken advantage of, besides stock injectors cost about as much as twix.

Edited July 17, 2016 by AdamB

[Dean_mc88]

I see what your saying.

my car personally is a second car and will be used on track and the odd road drive when it's nice. I suppose going off what you have said using the stock injectors will be fine and if they do go, replacing them won't be an issue !

[GP82]

See how it goes with the stock injectors, they should be more then enough. If for any reason you running outta fuel jus' go the next size up like a 315cc or maybe 330

[mech5107]

Although not much need for new injectors for stock turbo, if you want to really upgrade, get at least the newer style (slim plastic body) injectors.

RX8 red are 350ish and RX8 yellow are 430ish and usually cheap in the breakers.