Author Topic: two injector maps  (Read 8406 times)

Offline jesus-ninja

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two injector maps
« on: September 26, 2007, 03:06:48 pm »
OK, first post in here...

Is it possible to run two injector maps - eg for a 4 pot, 8 injector setup: Rather than a pair of injector banks supplying half the fuel each, have a primary bank of 4 which fuel until they hit, for example, 80% duty cycle, at which point a secondary bank supplement them.

Thinking this will allow for better refinement at low load / revs whilst maintaining the ability to pump high volumes at the other end of the scale.

Offline dnb

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Re: two injector maps
« Reply #1 on: September 26, 2007, 04:30:15 pm »
Yes, staged injection is possible.  (However I've not tried it.)

Unless your fuel demands are at the 2 extremes, I doubt you'll need to resort to this given modern injectors.  I have a clean idle using 600cc injectors on my 5 litre v8, and I know of people with 1000cc injectors with good idle on "small" 4 pots.

Offline jesus-ninja

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Re: two injector maps
« Reply #2 on: September 26, 2007, 05:19:12 pm »
Excellent - good to know. :)

Half way through fabbing up an 8 injector manifold. I'm going for VEMS anyway, and around 100 sheets a pice for 555s, when I have 4 370s here and no money then it's worth it, even if only to say I have!

Offline rob@vems.co.uk

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Re: two injector maps
« Reply #3 on: September 26, 2007, 06:04:38 pm »
I'd never phase injectors unless I absolutely had to, and then I'd need a lot of dyno time before I'd be happy that they were working correctly.
What I'd do is run the injectors in pairs and not bother phasing them... Then you'd get your 740's for nothing :)

Rob

Offline dnb

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Re: two injector maps
« Reply #4 on: September 26, 2007, 11:00:05 pm »
I think the only reason I'd want to phase is if I were going to be doing something like using methanol as fuel.

Offline rob@vems.co.uk

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Re: two injector maps
« Reply #5 on: September 27, 2007, 09:06:42 am »
I've been reading up, and the way that VEMS injector staging works is that once a set TPS and/or MAP value is reached the secondary injectors are phased in injecting by injecting a set % of the set PW.  You have the one VE map which describes the engine's fuel requirements which will remain set, and fuelling will be trimmed using the % of PW and the lambda table.

Offline Sprocket

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Re: two injector maps
« Reply #6 on: October 11, 2007, 08:30:44 pm »
I would also like to see two seperate maps for two sets of injectors running in parallel.

Can we have some experimental firmware plese ;D

Again, you know where im leading to with this :-*