Bigger injectors vs. Stock injectors..
- Thread starter LinuxRacr
- Start date
Fast lane said:
I think the discussion refers to all ove the above...
I personally am running 4 550's in the stock locations, and then 4 more 550's in a secondary fuel rail.
Drawbacks to a big injector: Poorer emissions from poorer atomization/burn, hardER (not HARD, just hard"er") to adjust idle due to lower cycling time and poorer atomization.
Pluses: Can remain at port injection. Can still maintain true sequential injection. Simpler setup (no manifold modification or injector block needed). Lower duty cycles for main injectors so less likelihood of injector failure in some cases. Poorer atomization can also result in greater cooling effect of the gasoline charge.
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- MSP
LinuxRacr said:
I know when I put my emanage in, that the stock injectors where almost at 100% duty cycle, so I had to put in bigger injectors.
Use stock injectors while not in boost so you can keep good idle ,good startups, and better emissions,that matters to some people, like me, but once boost starts to hit you have the bigger extra injectors kick in so the car can meet its fuel needs with out causeing stumbles out of boost. This is what im running and its only been a week but i have no problems and the cars i have seen doing this have not had problems unless they had other problems to begin with. I mean if you think of it , it all makes sense no need for the bigger injectors while out of boost its like driveing na.
This is my opinion and im not putting down anyone elses set up.
This is my opinion and im not putting down anyone elses set up.
Fast lane said:
I understand and agree... that's part of why I have two fuel rails... I've never had stumbles out of boost.. the ONLY thing at all out of the ordinary is my car idles a little rich and slightly rougher. But it idles better than my 91 blazer does... but slightly worse than the stock MSP we had. One of the downsides to having injectors upstream is that if your charge doesn't move fast enough or if you have bad pockets of recirculations you will get fuel buildup on the walls and there is no guarantee that the fuel gets delivered evenly... also, the air moves through each of the runners at slightly different speeds and thus you'll get a slightly different delivery of the mixture each time. Pre-TB gets around this a bit by "pre mixing" the air in theory... the downside there is that you end up with lower velocities over the injector tips and may not get as good of atomization and mixing as you might like.
All of the methods work plain and simple. Just each has it's pluses and minuses.
I'm curious to know if any engine management can control the duration of the spray and the patter like the stock ECU? With the stock MSP ecu we can get enough fuel for more than 12psi on the T25 on the stock injectors. However they run out of breath at around 8psi with any other fuel management. I've read that the stock ECU changes the width and the duration of the injectors accordingly?
Thanks.
Thanks.
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- MSP
That does not mean that it was right.
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- MSP
Where is the A/F charts from that dyno?
And show the duty cycle.
And show the duty cycle.
MPNick said:
I wasn't referring to the charge at idle being the one cooled. The size of the droplets coming from the injector orifices will still be larger regardless of air velocity... thus the energy absorbed in breaking them up and reaching vapor pressures will cool the charge... exactly why your hand feels cool when gasoline or alcohol evaporates off of it... energy is used to make the state transition... and it results in cooler overall charge temp.
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- MSP
MPNick said:
Yes I can post them but they are on discs right now I have to wait till I get home.
