BenB
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| posted on 6/2/07 at 09:24 PM |
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Injector sizing
What method has anyone used to decide what injectors to go for?
I used the method in A. Bell's Tuned Induction book but that gave me four injectors @ 320cc/min for 160Bhp (80% duty cycle)... which seems a bit
much considering the same injectors seemed fine for wildly tuned Turbo Cossies....
Whenever injectors came up on fleebay I'd check with Stan Weiss' injector table but most gave around 200cc/min. Interestingly, for most of
the injectors I looked up the .42 BSFC bhp estimate (80% duty cycle) for s/c'd intercooled engines was exactly what I needed...
So who's right? It seems strange that Bell's method is so mathematical but seems to be wrong!!!
Anyone else got a equation for working out injector sizing or is it just "find injectors from a car with similar Bhp" time....?
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TangoMan
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| posted on 6/2/07 at 09:42 PM |
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The file I have attached shows calcs for varying fuel pressures and duty cycles and the effect they have on available BHP from injector sizes.
This shows that 270cc injectors at 3bar and 85% duty will give 184bhp. enough for me. For now!!!
Summer's here!!!!
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BenB
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| posted on 6/2/07 at 10:55 PM |
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Cheers mate, I'll have a play and see what it recommends for my boosted setup....
Still can't work out why the amount of fuel you need for a given BHP depends upon whether you've used an intercooler, whether you're
NA / turbo etc etc... Never mind....
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TangoMan
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| posted on 6/2/07 at 10:59 PM |
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I am guessing it will because cooler air is more dense and therefore will require more fuel.
Summer's here!!!!
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02GF74
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| posted on 7/2/07 at 08:11 AM |
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take a look in burton pwer catalouge - list the ford injector colours for bhp.
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thomas4age
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| posted on 7/2/07 at 08:30 AM |
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isn't bell in that case reffering to mechanical injectors perhaps?
if not what fuel presure is he using?
grtz Thomas
If Lucas made guns, Wars wouldn't start either.
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Schrodinger
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| posted on 7/2/07 at 10:50 AM |
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There may also be the issue of whether you are firing the injectors in batch or sequential as to what BHP they will service.
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MikeRJ
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| posted on 7/2/07 at 11:34 AM |
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quote:
Originally posted by BenB
What method has anyone used to decide what injectors to go for?
I used the method in A. Bell's Tuned Induction book but that gave me four injectors @ 320cc/min for 160Bhp (80% duty cycle)... which seems a bit
much considering the same injectors seemed fine for wildly tuned Turbo Cossies....
All the injector size calculations I have found come out with ridiculous sized injectors. According to them the 20XE can barely produce stock power
(155bhp) on it's 214cc/min injectors, yet it manages to produce over 200 on the same injectors with just a modest hike in fuel pressure.
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BenB
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| posted on 7/2/07 at 01:13 PM |
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Okay, cheers everyone, I'll put in some cheapo tintop injectors and see what I get!!! I thought it seemed to accurate to be true!
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Schrodinger
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| posted on 7/2/07 at 05:38 PM |
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I had a set of injectors from a standard 2.0l blacktop zetec and a set from a VX which were supposed to be much better flow rates but when put on a
flow bench at Emerald they flowed the same. and provided my 1.8 Zetec with 150 bhp
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