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ste91

max bhp on 370cc injectors?

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Can anyone advise on what sort of power figure 370cc injectors are suitable for, keeping the duty cycle relatively safe around 75% max? 
Also running a Walbro 255 and Aeromotive FPR.

I initially bought a set of 370's as my original aim was around 230-240bhp, running a TF035 on a 4E but now I'm stepping up to a 5E and TD04 and hoping to make mid to high 200's power wise, so not sure if these 370's are going to be good enough anymore although I've already had them cleaned and flow tested so it's a little bit annoying if I have to find and test another set.

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I had a quick check on some of the on line fuel injector calculators from deatschwerks and fuel injector clinic and at 80% duty cycle for 290 bhp it showed that 500 to 600 cc injectors were required! Seems high to me. Depends on the BSFC number they use for their definition of "turbocharged" though. The lower the base fuel pressure, duty cycle allowed and the worse the bsfc the bigger the injector size required.

It says the 370cc is good for 188bhp at the crank?!? (3 bar fp and 80% dc)

255lph pump should be good for 500bhp apparently.

I'm sure someone with actual experience will be able to comment. Seem to remember reading the 430cc's were ok to 300 bhp.

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I had the same, checked a few online calculators and they all give out silly results. My next step would probably be a set of 430 (RX7?) injectors as you say, just wondered what I could get away with on the 370's to save the hassle of finding and testing another set. Had a lot of trouble with injectors in the past, waited forever for them to be tested, one set ended up being unusable, another set lost in the post etc...

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53 minutes ago, ste91 said:

I had the same, checked a few online calculators and they all give out silly results. My next step would probably be a set of 430 (RX7?) injectors as you say, just wondered what I could get away with on the 370's to save the hassle of finding and testing another set. Had a lot of trouble with injectors in the past, waited forever for them to be tested, one set ended up being unusable, another set lost in the post etc...

Think the 370's would be out of duty for your purposes. Sucks about the injectors you've lost, I've got a set of 295cc fte injectors that I'm dreading sending off for cleaning in case they're stuck solid!

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1 hour ago, Claymore said:

Think the 370's would be out of duty for your purposes. Sucks about the injectors you've lost, I've got a set of 295cc fte injectors that I'm dreading sending off for cleaning in case they're stuck solid!

I have a mate with a set of 295's that have been cleaned and tested for sale if they're any good to you?

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39 minutes ago, ste91 said:

I have a mate with a set of 295's that have been cleaned and tested for sale if they're any good to you?

Thanks for the offer mate, but I'll give my ones a chance. Fingers crossed.

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If youre trying to hit late 2's/3's i think youll find the 370cc's too small. 440's are good just about for low 300's so i would atleast go up to them, however the denso 440cc doesnt have the nicest injector characteristics. 

If you want to be sure id run a new Bosch or Injector Dynamics, you'll have plenty of cc headroom and have better control than the older Denso's. You can get the Bosch in a 550cc.

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6 hours ago, RobSR said:

If youre trying to hit late 2's/3's i think youll find the 370cc's too small. 440's are good just about for low 300's so i would atleast go up to them, however the denso 440cc doesnt have the nicest injector characteristics. 

If you want to be sure id run a new Bosch or Injector Dynamics, you'll have plenty of cc headroom and have better control than the older Denso's. You can get the Bosch in a 550cc.

Funnily enough I discovered the Bosch EV14 550's earlier and started looking at them, reasonably priced, especially when you consider a 2nd hand set of RX7 440s plus cleaning/testing will probably set you back £150 anyway, a little extra gets you a brand new set of Bosch injectors with a more modern design, it's a no brainer, the only thing is there are a LOT of these Bosch 550's being sold and I'm skeptical about fakes, can you recommend anywhere reliable that stocks them? Your site only has Injector Dynamics as far as I can see.

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1 hour ago, ste91 said:

Funnily enough I discovered the Bosch EV14 550's earlier and started looking at them, reasonably priced, especially when you consider a 2nd hand set of RX7 440s plus cleaning/testing will probably set you back £150 anyway, a little extra gets you a brand new set of Bosch injectors with a more modern design, it's a no brainer, the only thing is there are a LOT of these Bosch 550's being sold and I'm skeptical about fakes, can you recommend anywhere reliable that stocks them? Your site only has Injector Dynamics as far as I can see.

CP fuel injection 

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subaru sti 550/565cc injectors also work (pink or dark blue) and have a nice spray pattern

you will need to remove two of the black plastic pieces that are used as spacers on the fuel rail, as they are a little shorter than the stock injectors

this is an option if you can get them cheap

Edited by gorganl2000

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i've had the blue 550/565cc subaru injectors in since 2018...no issues at all

they usually sell very cheap on the subaru/sti forums...a used set cost me around US$100 + shipping back then,  so may be around gbp100 if you get lucky

PS--if you go this route, PLEASE make sure you get genuine ones, they are a LOT of fake cheap chinese ones on ebay

 

Edited by gorganl2000

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