avatar382 Posted July 1, 2005 Share Posted July 1, 2005 Ok guys, I got 2 cold start injectors, one from an old Saab, another from a Volkswagen. Thanks goes to BoostedBalls for the inspiration! The idea is to drill a hole in my piping from IC to throttlebody, about 6 inches to the throttle body, and plumb the injector in there. Then, I get a pressure switch and have it activate the injector at a certain PSI. I am thinking probably 7, 8 PSI. Hopefully, this will allow me to get all the way to maybe 12, 13 psi without worrying about melting a piston. Turned it down to 9 psi at the Dragon because I was worried about running lean, and haven't touched it. The injector will get fuel from a tee that I will install at the fuel filter. I have two injectors, but I'm only installing one, for now. Eventually, I might even add the 6th injector to come on at ultra high boost! 15 psi, here I come! Take that, Subaru with very small stock injectors! I will post pics! Wish me luck! I'm going to try this tomorrow. If I blow up my car, I will post pics too! Quote Link to comment Share on other sites More sharing options...
Vanislru Posted July 1, 2005 Share Posted July 1, 2005 Nice! I was hoping to have megasquirted my cars by now but I'm thinking that I'll go the 5th injector route too until then. Cold start injectors are plentiful and pressure sol.'s too. Good luck! Quote Link to comment Share on other sites More sharing options...
avatar382 Posted July 1, 2005 Author Share Posted July 1, 2005 BoostedBalls: How did you tune your extra injector without a wideband 02 sensor (figure out where it leans out) and wideband A/F gauge? A narrowband A/F is only good for reading between 13.5 and 15.5.... 13.5 is still way too lean! I'm serisouly considering dropping 400 bucks on a freaking wideband 02 sensor.... am I crazy for doing this on a 17 year old car?! Aaaah this speed stuff is getting expensive.... Quote Link to comment Share on other sites More sharing options...
oddcomp Posted July 1, 2005 Share Posted July 1, 2005 um yeah the 5th injector route will usually work to help cover the hole in stock ecu's fuel delivery mapping that being said.. its pretty much a band-aid type thing that does work but one of the downsides of it is 2 much fuel can also make it bog down plus it has a tendancy to wash out that reallly thin layer of oil in th cylinder walls that a helps seal the cylinder to the rings and b helps keep the rings from eating the cylinder walls having just idiotically blathered about that. many people do run 5th injectors just fine with no problems boostedballs,skip and i thinka few others plus its common on other turbo cars as a fix for a fueling hole that the stock ecu/injectors can't compensate for the stock injectors can keep up with the demand since at 10 psi with a megasquirt and edis setup i was actually running rich enough to bog down the motor at 3/4 to wide open throttle wide band is a great idea since you can use it to sort out your 5th injector size so it is not over kill or not enough Quote Link to comment Share on other sites More sharing options...
avatar382 Posted July 5, 2005 Author Share Posted July 5, 2005 update: project currently on hold pending an EGT gague install. Anyone have any experience installing EGT probe on the TWE headers? Quote Link to comment Share on other sites More sharing options...
BoostedBalls Posted July 29, 2005 Share Posted July 29, 2005 I'm glad to be an inspiration, or was that perspiration? I'm happy with either! I didn't use a wide band, my budget for this car wouldn't allow it. Other projects are draining my wallet. I just used a stock sensor and autometer A/F gauge. Very sloppy readings I know, but I could see when the gauge went and stayed lean, That was 16-19 psi somewhere; boost comes on pretty fast and it's hard to tell if the needle on my boost gauge is responding quickly enough. I had an adjustable pressure switch in the console that I used to adjust the 5th injector beetween speed blasts. I got the best reading and response with the switch set at 12psi. Less than that made it bog a little. I was running an open down pipe so it may be different on a full exhaust system. The whole time I was running this setup I was assuming that I was doing serious damage but I liked the power and the car was cheap. No thrills better than cheap thrills right? Well, I opened the engine up for a rebuild last winter and found the cylinder walls to be in awesome condition. I should have just pulled the heads and freshened them up. This was on an engine with about 200k on it! * I have patterns for building a large water-to-air intercooler for these cars. I have built one already and I'll post photos of it after installation. I'll hook up some thermocouples to monitor inlet and outlet temps too! Yeah baby! Quote Link to comment Share on other sites More sharing options...
WJM Posted July 30, 2005 Share Posted July 30, 2005 Methanol injection. Quote Link to comment Share on other sites More sharing options...
BoostedBalls Posted July 31, 2005 Share Posted July 31, 2005 Yes! Methanol is the ticket. I want to setup methanol/H20 @ 50/50 to come on in stages from 15, 20 and 25psi. I think 25psi should be like pulling the pin from a grenade! Quote Link to comment Share on other sites More sharing options...
ausubaru92 Posted July 31, 2005 Share Posted July 31, 2005 Even though i dont have a turbo,.. I was thinking... The a normal injector is controled by a pulsating voltage and the flow rate is controled by the length of the pulses,.. so If you could make a simple wave generator and have the length of the pulses controled by a pressure sensor, you could have a variable fuel flow through the 5th injector controled directly by boost pressure. Just a thought, im sure there are some electrical engineers about on this board Gannon Quote Link to comment Share on other sites More sharing options...
Adam N.D.J. Posted July 31, 2005 Share Posted July 31, 2005 one way that I was thinking of doing this is to tap into the module signal from the computer, run this to another module that would pulse the injector at the same speed that the engine is running. Have this set up to run off a pressure sensor, so that when you hit say 10psi, the fifth injector starts recieving signal. And if your at 10psi at 3K rpms, that would work out to about 40% duty cycle on the injector, then as you go up in rpm, (and boost) the injectors duty cycle increases so that when you hit 6K rpms, the injector is full open (100% duty cycle). Just some thoughts that I have been playing around with. Quote Link to comment Share on other sites More sharing options...
BoostedBalls Posted July 31, 2005 Share Posted July 31, 2005 The 5th injector isn't a peak-and-hold type like your other 4. It would not respond quickly enough for it to be effective in that setup. The 5th injector comes on with 12vdc and stays on, it makes a nice mist of fuel too. You can stage a few of them to come on in 3 or 4psi increments with 3 different pressure switches. It's not the greatest way to control the A/F but I would bet it works better than a carb. I'll be setting up at least one more injector on mine when I decide to turn the boost over 20. I gotta have the H2O/alky injection first. Quote Link to comment Share on other sites More sharing options...
ausubaru92 Posted August 1, 2005 Share Posted August 1, 2005 My origional intention was to use a normal injector Adam N.D.J..... i like ur idea This was taken from the wongleflute Smith Electronics site DC Motor Controller Kit Circuit is designed to control 12VDC mini drill motors or lights with currents up to 1 amp Employs the pulse-width modulation (PWM) technique to send bursts of current to the motor, providing an efficient means of varying motor speed Power source required: 12 volts DC Supplied with components, PCB and heatsink for the switching transistor Optional case (use H-2853) PCB dimensions:43mm x 61mm A$16.69 incl GST One from http://www.fairradio.com/kits.htm DC TO PULSE WIDTH MODULATOR for control for DC motors, lighting, small heaters. Pulse width modulation (PWM) produces a series of pulses whose duration is proportional to a DC voltage. This allows for very efficient control of DC motors and other DC operated devices. Overload and short circuit protected. Input voltage 8 - 35 VDC output current 6.5A. Dimensions: 3.4"x1.9"x1.8". #K8004, $22.95 It uses Pulses of voltage to control the output, which is the same as the ecu doesnt it? (feel free to prove me wrong) I though that if you replaced the potentimeter with a pressure sensor, it would vary the pulses and thus the injector output Just an idea *edit: http://www.solorb.com/elect/solarcirc/pwm1/ is a page on theory and construction.* Gannon Quote Link to comment Share on other sites More sharing options...
BoostedBalls Posted August 1, 2005 Share Posted August 1, 2005 Interesting idea, I have a similar circuit that is much larger that I am planning on using to build an electric go cart for my little boy. It will use a 12v marine battery and chevy truck starter. The potentiometer will be hooked up to the 'gas' peddal. It should work for injectors, but if you wanted to use regular peak and hold injectors- why not just build a circuit that activates at 12 psi or so that uses the stock injectors to trigger 4 separate power transistors which power 4 secondary injectors? The car would drive like normal until you hit 12psi and the computer instantly drives 2 injectors at each intake port. The ECM would reduce the pulsewidth because it would go rich for an instant, then as boost increases even more- pulsewidth would increase again. But why not just go MegaSquirt??? I'm gearing up for it soon. I just need to find out how to feed boost pressures over 20psi with it. I'm hoping ODDCOMP will give me a hand. He's already running MS. -Chuck- Quote Link to comment Share on other sites More sharing options...
NorthWet Posted August 1, 2005 Share Posted August 1, 2005 The trouble with that motor controller is that it makes no provision for engine speed. What you need is something that puts out a single variable-width pulse when triggered by the ECU's injector signal. My thoughts in this vein are how about using an SPFI throttle body, and use its fuel metering capabilities??? But I believe that all of this is just band-aid, and that proper fuel management (ala MS) would be much better. Quote Link to comment Share on other sites More sharing options...
JWX Posted August 2, 2005 Share Posted August 2, 2005 their was a thread where that was debated, and I thought it was this one but it doesn't seem to be there anymore Quote Link to comment Share on other sites More sharing options...
Myxalplyx Posted September 10, 2005 Share Posted September 10, 2005 Avatar, How did your 5th fuel injector install go? Quote Link to comment Share on other sites More sharing options...
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