Auxillary injector system

[Darknight]

Here's an idea. NOS wet systems inject extra fuel along with their added oxygen supply to prevent detonation and increase power. Why not have an extra injector or set of them that would only operate under maximum throttle and boost?

DK

[Arctc Wolf]

where would u place these extra injectors, what would control them, how big will they be, and when will u have them come on?

[Darknight]

These injectors would be very small compared to the regular injectors, to avoid over-richening the mixture. I'm thinking half the size, if they make them. I would probably place them before the main injectors, but that would take some time to figure out for sure. I would attempt, if I were building it, to fix a control module which would read the O2 sensor to detect a lean/rich condition. If it was too lean, I would have the injectors kick in. It's all just theory...something that popped into my head earlier today. i couldn't make any too specific claims about it.

DK

[Arctc Wolf]

Perhaps a secondary injector control system would work. dyno tuning would be important. the secondary injectors could be as big as u want since the primary ones would be the only ones to come on at low rpm's. At higher rpm's, the secondary ones can be adjusted according to fuel pressure to provide enough fuel. the problem is, where in the intake runner will u be able to fit the injector bung.

[Darknight]

you could put a big secondary injector in, but you would probably never get enough air coming into the engine to need that much extra fuel. you'd be better off with a smaller injector, so the spray would be finer. as far as mounting the injector, I'm not exactly sure, but I'd say it can be done.

DK

[Arctc Wolf]

I would suggest sticking w/ a stock fuel injector, and just adding another set of stock injectors, since 50 lb. injectors can support up to ~600 crank hp, the doubled up stock injectors add up to 44 lbs. per hr. I think, so u should be fine for pretty much anything. why do u think you'll need an extra set of injectors?

[Darknight]

I don't exactly follow. You just said that you recommend an extra set of injectors, and then ask me why I think I need another set of injectors.

[Arctc Wolf]

i suggested getting another set of stock sized fuel injectors just because I doubt u'll be making more than 600 crank hp anytime soon. U haven't told me what the application of the extra injectors will be, so that's why I'm asking. If it's gonna be a NA motor, u won't need them at all. I think the only application where u might need that much fuel and that precise fuel metering would be a turbo setup for very high boost levels on low compression and 7000 rpm's.

[Darknight]

The idea was for any forced induction engine, if an engine has a tendency to run lean. That way, instead of raising fuel pressure so much, and adding an inline fuel pump and et cetera as many do, you could handle as much air as you could pump in without going too lean.

DK

[Arctc Wolf]

you would still want a bigger fuel pump to feed the extra injectors, but I understand what ur saying. It makes sense, but the question comes back down to the placement of the injectors, since you want it timed just right to get enough fuel into the cylinder at the right time and to also prevent fuel puddling on the valves. L67 engines use a different cylinder head that has the injector places inside the head. this is because the eaton blower takes up all of the space where the fuel injectors would normally go. I have thought about using a set of these to add another set of injectors w/o having to drill and plumb a whole new system into the intake tract. What do u think about this idea?

[Morgan]

DK,

Your post above referred to "forced induction" only so I'll work from the perspective you have have intended to take the turbo approach...that said, 7th &/or 8th injectors have been used in the past on GN/TRs, although the approach is a bit old school now. These injector(s) (typically a 36# Blue Top or a 42.5# Lucas 009, or both) would be mounted in the up-pipe leading from the intercooler to the TB, with fuel tapped from the test port/Schrader valve on the fuel rail. One approach I've seen used a manual triggering process where the driver monitored an EGT gauge. As the EGT climbed to "Yellow Alert" as it were, he'd reach down and flip a long handled toggle switch to engage the 7th. This usually took place at about the 1/8th mile mark. It also kept the driver pretty busy, as he was also manually shifting the car on his low 10-second runs.

Chip technology has advanced now where it's possible to run large injectors and still maintain good street manners. I used to run six 55# injectors, and passed our CA Smog Poleizi chassis dyno test with flying colors with a fresh cat on the car. I now run 72#ers; they are controlled by a stock ECM modified with different drivers to allow usage of large (over 50#/hr) injectors. The nice thing is that I can stick in a set of Lucas 009s (42.5#ers) with the proper chip and the modified ECM can still run them.

Hope this helps,
Morgan

[ March 08, 2003: Message edited by: Morgan ]</p>