gavin174
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| posted on 19/12/11 at 07:30 PM |
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Secondary Injectors
to follow on from this thread http://www.locostbuilders.co.uk/forum/9/viewthread.php?tid=164238#
I was talking to someone at our club meet yesterday, about the possibility of running 2 sets of injectors
I have a few questions on this....
do bikes have 2 stages to make them "safer" and easier to keep the front wheel on the floor, or is there another reason..
is it possible to use an Omex 600 to control 2 sets of injectors to create a 2nd injection of fuel at high revs....
and most importantly am i over complicating things for no reason!!!
cheers Gavin
http://www.essexkitcarclub.com
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matt_gsxr
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| posted on 19/12/11 at 07:40 PM |
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Injecting further away from the inlet valve has two benefits.
1) the fuel gets to mix really well with the air
2) the fuel takes heat out of the air and increases the density
This only really works when the airflow is fairly high (otherwise the fuel just drops out onto the inlet manifold).
According to various sources you can gain 3-5% power.
Tuning secondaries with megasquirt wasn't difficult (even I could do it). No experience of Omex.
Matt
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plentywahalla
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| posted on 19/12/11 at 07:40 PM |
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I was going to do this with my Zetec and did some research on it. As I understand it different velocities of air flow need the injectors at different
distances from the port, near for slow running, further away for fast running. So the most efficient is to use the bank near the head and then feed in
the outer bank as the revs rise.
You can use the Omex if it is configured for 8 cylinder engine on a four cylinder, its all in the mapping.
As I said, I never actually did it so it is all theoretical .... someone will be along in a minute and say it is all B****ocks
Rules are for the guidance of wise men ... and the obedience of fools. (anon)
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snapper
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| posted on 19/12/11 at 07:53 PM |
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The above posts are correct, Dave Walker did an article in Car & Car Conversions a few decades back, he found that the change over point was fairy
critical and that you run both sets of injectors for a single engine rotation or it stuttered, can't remember if he reduced the fuel charge at
crossover or ran two full shots.
Best to set up for the first set of injectors close to the head then fabricate the second set in an air box and start playing.
Dave Walker also developed a 5th injector system on a Golf with 4 injectors and a single throttle body
I eat to survive
I drink to forget
I breath to pi55 my ex wife off (and now my ex partner)
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gavin174
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| posted on 19/12/11 at 07:57 PM |
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have had a bit of a look into omex 600 its only capable of running a 4 cylinder engine
omex 710 is over a £1000 so think I will be running one set of injectors...
or does anyone know another option.
cheers
http://www.essexkitcarclub.com
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matt_gsxr
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| posted on 19/12/11 at 07:59 PM |
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The cbr1000rr outer injectors aren't a bad choice (depending on how your airbox is configured) and are dirt cheap. The only problem is there
flow rate isn't that high.
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matt_gsxr
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| posted on 19/12/11 at 08:01 PM |
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On the megasquirt I only have two injector drivers set-up. But used one feed to drive one bank of 4 injectors, and the other feed to drive the other
bank and run batch mode. This isn't a problem as long as the injectors are high impedance (14Ohm) and not those 3Ohm ones.
Perhaps you can do a similar trick with the Omex?
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gavin174
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| posted on 19/12/11 at 08:02 PM |
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i was hoping to use standard ford injectors in the ST manifold
and the standard GSXR ones in the TB's...
http://www.essexkitcarclub.com
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gavin174
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| posted on 19/12/11 at 08:08 PM |
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just found this info on the Omex 600
ECU OUTPUTS.
Injectors
The 600 series ECU has two injector outptuts that are used to control 4 injectors semi-sequentially or up to 8 cylinders batch fired. Injectors should
be high impedence, but low impedence injectors can be used with ballast resistors........
does that sound like what you were talking about Matt
http://www.essexkitcarclub.com
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SeanStone
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| posted on 19/12/11 at 08:20 PM |
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I can put you towards someone to get the 710 for under a grand if it is needed...not much under, but under!
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speedstar
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| posted on 20/12/11 at 09:21 AM |
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quote:
Originally posted by gavin174
i was hoping to use standard ford injectors in the ST manifold
and the standard GSXR ones in the TB's...
Was thinking exactly the sane thing using megasquirt... If that's possible?
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will121
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| posted on 20/12/11 at 09:33 AM |
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i have a zetec running twin injectors running staged injection but using a Emerald ECU, think inner injectors go up to 3500rpm then switch to outer
ones. as Emerald has 3 switchable maps Initial plan was to run it and test it with all the options to see what difference it made just inners, just
outers then both staged but the extra cost of mapping i never got round to it so cant confirm benefits.
Personally as most run just a single injector with good results dont know if its really worth the extra work of wiring, fuel rails etc.
Also other things to considder is extra space required and getting a base map to run single injection should be easy but bet a stage injector one wont
be so more time and possibly extra expence for RR mapping.
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