just wondering the biggest injectors i can run with on pump sorry if this is a stupid Q Ive asked my friends and they all say nothing over 900cc but if i get a tune for whatever i put in i dont understand how i cant just go big? i thought injector just were valves you tune them for how much you wanted to open? again thats just me thinking?????????
LOL! 900, 1600, 2000, they can all be ran on pump fuel. However, the problem lies in what you are trying to control them with. Stock ECU? Hyrda? Autronic? Link? What are you actually trying to do here? That is the million dollar question.........
I expect part of his question has to do with driveability, especially idle. If they are too large it can be hard to get short enough injector pulse widths in low load situations. This is obviously more of an issue with pump gas VS E85 since less fuel is required. My experience is limited, but I am running modded stockers which flow 912cc and I have not noticed any problems with idle or low throttle. I know when a lot of the DSM guys switched to E85 they were running 1600cc injectors and starting to run in to minor issues (Equivalent to about 1100cc on pump). Some people opted to limit their goals a bit and stick with 1,200cc injectors to make tuning and daily driving a little easier. (~840cc on pump). I guess that's a long way of saying I don't really know, but hopefully the info is at least marginally useful. I'm betting one of our local tuners will step in and shed some more light on this for you. How big do you really need? Surely 900cc is plenty for any reasonable goal.
The idle problem you are referring to does in fact have to do with injector pulse width. Most people running large, low impedance injectors are not running them properly. Low impedance injectors are meant to be ran in a peak-and-hold method, verses the typical saturated method. Most people slap in a resistor box so they can run low impedance injectors for cheap. Therein lies the problem. Low impedance injectors are designed for a 4 amp peak to open the injectors, and a 1 amp current to hold the injectors open. Saturated is just a straight voltage that is limited by the resistance of the injector (and resistor box, possibly). Without enough current running through the injector coil, the injector will be slow to respond. Hence the problem a lot of people have with large injectors. A properly ran large, low impedance injector will have a response time of less than one millisecond (down to .7). Saturated or high impedance injectors are around 1.5ms, even the ID's. A simple and relatively inexpensive solution is the low impedance injector driver from FJO Racing Products.
That was a hell of an answer and pretty much all new to me, but I also thought that at a certain flow rate the minimum time the injector could be open exceeded the fuel needs even with good response time?
It's a good answer because we've studied the question in depth together every single time he's come to my house in last 3 years. It's exactly the problem that has been plaguing my car for some time. The solution he listed, the FJO controller, would be the likely fix. I'm just too damn lazy at this point to bother with all the work that would be required to do it. At this point, I'd rather sell the car and tell the new owner what to buy and let him or her make 500whp.
Lol. Nah. That got old a while ago. If I can't get under your skin about it, there really isn't any fun in it anymore. Besides, your car runs.... A lot of people with 1.8L Hondas think they can use the factory resistor box since the cars came with low impedance injectors stock. Then they wonder why they need to keep their idle so high for it to run worth a damn with large injectors. There are a number of variables that affect where that point is. A 2.5L engine will give your more room to play with than a 2.0. Base fuel pressure obviously has an effect. Spray pattern and temperature change how effectively your fuel is atomizing. What you define as good response time is a huge factor too. .8ms flows almost half the fuel that 1.5ms does. So yes, there will be a point that a particular setup will run into a wall in terms of good idle. That point isn't always in the same spot, however.
loaded question so here's the mod list 2.5 hybrid with chambered 2.0 heads. mahle forged pistons 99.5 mm, acl race bearings, acl race rod bearing journal 52mm, tgv delete, coated tgv and intake manifold, billet 20g ball bearing center cartridge turbo, cometic gaskets, custom buckets and a good size pump. still have the stock intake but i do have a deleter elbow. and only 420cc injectors i know laughable 4 the set up but that's why im asking. really all i want to do with this motor is go faster than you.
I hope you mean the royal "you". You do not need injectors to be faster than my winter beater. If you mean my real car, keep trying. :biggrin:
lol easy turbo, ill still keep up? i wanted one but the ball 20g starts spoolin at idle and i couldn't justifi the money when im remodeling the house :-( spent the budget on the tv's lol
and it was the royal but if we Wan2 get into this lets wait till summer im sure you'll win my setup isn't 4 speed i like sitting sideways way 2much
Just giving you a hard time. I'd rather own a home right now rather than be balls deep in a damn Subaru. This is my last modified Subaru, and for good reason.
I'm exactly opposite. We have a house and have been trying to build another for the past three years... I can tell you I'd rather be balls deep in a Subaru than balls deep with the mortgage companies!
