mrwibble
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| posted on 11/11/11 at 02:18 PM |
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down side to higher fuel pressure?
After some research for my toy car, I've come to the conclusion that the 240cc/min injectors i've had with my gsxr 600 TBs will require
more than 3bar of pressure to achieve my upper limit 160-170 bhp on a standard 2.0 zetec on the aforementioned TBs.
I'm currently running a zetec in my tin top at closer to 50psi with stock fuel system with no known issues and has been that way for a couple of
years.
So my question is will there be any issues running up to 55psi pressure through a variable regulator, plan is to use omex management, custom manifold
and custom respaced fuel rail to suit suzuki injectors. wondered if it complicates fuel pump choice?
any help appreciated.
Ed.
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BenB
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| posted on 11/11/11 at 02:30 PM |
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The injectors will find it difficult to open so they'll pull more current and open slower. And of course you're more likely to get fuel
leaks and if you're really unlucky you'll rupture the diaphragm in the regulator.
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mrwibble
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| posted on 11/11/11 at 02:41 PM |
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hmm, sounds scary! I guess 25% more pressure might be pushing it a bit far, the alternative is to run at 3bar and be down on power i guess, or shell
out on new injectors...
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Bluemoon
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| posted on 11/11/11 at 02:46 PM |
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Or add secondary injectors?
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mrwibble
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| posted on 11/11/11 at 02:53 PM |
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quote:
Originally posted by Bluemoon
Or add secondary injectors?
hah! interesting thought, not sure omex 600 caters for 8 injectors, as its designed for 4 cyl engines, anybody else know?
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jeffw
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| posted on 11/11/11 at 03:06 PM |
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I'm running 4Bar on the injectors in my Jenveys. In fact Atspeed changed it from 3Bar to 4bar on the rollers to help with the power. I am
running bigger injectors than you though at 400cc.
I doubt you would have an issue this side of 5Bar.
[Edited on 11/11/11 by jeffw]
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Oddified
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| posted on 11/11/11 at 03:22 PM |
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I'm running my gsxr injectors at 4bar for exactly the same reason as your looking at, works perfectly. I'm using the gsxr 750 K4 bodies
though, so i can't be sure your injectors are identical or not. Researching the 750 injectors of that era, i found the figure of 270cc/min but
there's so much conflicting info out there....
Ian
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coyoteboy
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| posted on 11/11/11 at 03:22 PM |
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Be wary - doubling the fuel pressure doesn't double fuel flow. Running a whole bar higher will only give you an extra 15% fuel.
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mrwibble
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| posted on 11/11/11 at 03:26 PM |
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cheers, i used
SUZUKI GSXR 600 GSXR600 K1 RECON INJECTORS CRV VFR1000 | eBay
this is basically what i'm basing my info on for 240cc/min. not 100% my TBs are k1 but they're split into individuals and look just like
the ones claiming to be k1-k3 on ebay.
[Edited on 11/11/11 by mrwibble]
[Edited on 11/11/11 by mrwibble]
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coyoteboy
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| posted on 11/11/11 at 03:33 PM |
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Yup, gaining you an extra 4.8% for your 5psi hike. I recently considered upping the FP to save me getting540s instead of my 440s, realised that was a
non-starter 
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Oddified
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| posted on 11/11/11 at 03:41 PM |
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quote:
Originally posted by mrwibble
SUZUKI GSXR 600 GSXR600 K1 RECON INJECTORS CRV VFR1000 | eBay
this is basically what i'm basing my info on for 240cc/min. not 100% my TBs are k1 but they're split into individuals and look just like
the ones claiming to be k1-k3 on ebay.
They're a totally different injector to what's on the 750 K4 that i'm using. I don't know the flow rate of the ones you have
sorry.
Ian
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mrwibble
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| posted on 11/11/11 at 03:44 PM |
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quote:
Originally posted by coyoteboy
Yup, gaining you an extra 4.8% for your 5psi hike. I recently considered upping the FP to save me getting540s instead of my 440s, realised that was a
non-starter
 from rceng.com which i found today, to achieve 170 bhp i need 4bar or 59psi to with 240cc/min rated injectors, i guess in reality my injectors are
likely to be working less than optimal anyway.
any DIY injector cleaning ideas? wash with petrol?
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mrwibble
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| posted on 11/11/11 at 04:07 PM |
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quote:
Originally posted by Oddified
quote:
Originally posted by mrwibble
SUZUKI GSXR 600 GSXR600 K1 RECON INJECTORS CRV VFR1000 | eBay
this is basically what i'm basing my info on for 240cc/min. not 100% my TBs are k1 but they're split into individuals and look just like
the ones claiming to be k1-k3 on ebay.
They're a totally different injector to what's on the 750 K4 that i'm using. I don't know the flow rate of the ones you have
sorry.
Ian
i keep coming up with 240cc number. i think its as good a basis as any. basically i'm gonna bung it together and hope that it works, but its
just peace of mind that I can increase pressure with some risks, but i'm not quite stepping into the dark as before. many thanks for all
input.
Ed.
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MikeRJ
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| posted on 11/11/11 at 05:34 PM |
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quote:
Originally posted by mrwibble
[ from rceng.com which i found today, to achieve 170 bhp i need 4bar or 59psi to with 240cc/min rated injectors, i guess in reality my injectors are
likely to be working less than optimal anyway.
I wouldn't worry too much about these on-line calculators, they seem to give very pessimistic results. The 20XE made 155bhp in standard form
with 214cc injectors, and the SBD kit that takes it to 200bhp retains the standard injectors (but ups the fuel pressure by 1 bar or so).
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AdrianH
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| posted on 11/11/11 at 08:17 PM |
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Pardon me for what could be a very daft idea, but would it not be possible to have the injectors batch fire in two's 1 and 4, 3 and 2?
That way the injectors are loading the inlet trumpet on the power stroke and take that preloaded fuel in on the inlet stroke together with another
charge on the inlet as the injector fires again.
Something about it in the Graham Bell book I have. Do not know what the Omex can do so may not be an option. It does say it is a way of using
smaller injectors to get more fuel.
Adrian
Why do I have to make the tools to finish the job? More time then money.
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coyoteboy
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| posted on 11/11/11 at 08:46 PM |
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Effectively 2 squirts per cycle in MS terms? Won't give you more fuel, in fact it'll give you less as you have the dead time involved in a
second set of opens and closes. In extreme situations you end up squirting across almost the entire 720 degrees anyway with one squirt. Two squirts
per cycle tends to give a smoother idle.
[Edited on 11/11/11 by coyoteboy]
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paulf
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| posted on 11/11/11 at 09:25 PM |
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I think the early gsxr injectors are all the same across the range from 600 to 1000 cc.Many people seem to run standard injectors on 2 litre zetecs
with no problem, I have 600 throttle body's with standard injectors and although I have not had the car on a rolling road it has been mapped on
the road to run well and maximum duty cycle never goes above 85% using a 3 bar fixed regulator.
Paul
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Oddified
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| posted on 28/11/11 at 03:49 PM |
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Might be usefull info, i've just done a flow test on the gsxr 750 K4 injectors at 4bar. Reasonably accurate without getting them properly tested
somewhere.... stop watch, proper measuring cylinder (not just the kitchen jug!) and tested several times to confirm. They came out at 315cc/min which
sort of confirms the formula's for increasing the fuel pressure from 3bar (supposed to be around 270cc/min at 3bar).
The gsxr 750 K4 uses these injectors;-
Might be handy info for anyone looking at bike itb's. I have them on a NA cosworth and they work a treat
Ian
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