Author Topic: 30# injectors  (Read 5235 times)

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yooperjeep

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30# injectors
« on: August 11, 2009, 10:01:05 AM »
Does anyone know of any stock cars out there that run 30lb injectors which would fit in 2.5l? I would like to pick some up from the local salvage yard if possible. I found some new ones on ebay, but I was hoping to save a few bucks. Thanks

Offline sharpxmen

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Re: 30# injectors
« Reply #1 on: August 11, 2009, 10:34:36 AM »
not stock but i bought 32lb/hr Accel which are 30lb/hr with the fuel pressure on my '95 YJ and would be more than 32 on the 96+ fuel pressure. if you don't mind me asking why are you looking for that much flow (it is 70% more than the 91-95 and 30% more than the 96+ models) are you supercharging?
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
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yooperjeep

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Re: 30# injectors
« Reply #2 on: August 12, 2009, 06:07:57 AM »
I am starting to gather parts for a turbo set-up. As most people are, I am trying to keep this as low budget as possible, so if anyone knows of good places to find turbo related parts just let me know. I would like to get alot of parts from other cars (salvage) to keep the cost down. How much did you pay for your Accel injectors?

Offline sharpxmen

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Re: 30# injectors
« Reply #3 on: August 12, 2009, 07:13:50 AM »
got a set of 8 off ebay a while ago (2 years ago), can't remember exactly. what year is your Jeep and how much boost are you planning to run - depending on those 2 factors you can determine what injectors you need (with 32lb/hr injectors for a 91-95 Jeep you should have around 12psi boost if you don't alter the ecu or fuel pressure in any way), and also keep in mind that you need high impedance injectors and i think the connector type is EV1 (or something like that). I can try and look for the vehicles that used injectors with a flow close to what you need if you let me know your model and boost.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
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yooperjeep

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Re: 30# injectors
« Reply #4 on: August 12, 2009, 07:20:34 AM »
I have a 94 with the 2.5l. I am only looking to boost about 6-8psi for now. So if I match the right size injector with the amount of boost I am putting in I should be able to run without any changes to my fuel pressure or ECU? Would it still be good to put in a fuel pressure regulator? I was planning on putting the split second unit on so I could do some custom tuning. Any information you can give would be appreciated.

Offline sharpxmen

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Re: 30# injectors
« Reply #5 on: August 12, 2009, 08:41:54 AM »
it's a good start to have the injectors matched based on the amount of air you put in, but for fine tuning you're right to use the split second (at least the one that controls the MAP output if not the timing as well - PSC or FTC, and/or one of the MSD/Vortech timing calibrators - but here also depends where your boost kicks in and how much boost you run). If you plan to have 6 to 8 psi boost a close estimate would be 24 to 26 lb/hr at 39psi fuel pressure (40 % more at 6 psi and 55% more for 8 psi), you can go for higher or lower and then adjust the pressure. You also have to account for the increase in fuel pressure under boost since your FPR will increase the pressure once under boost by using the vacuum port - that is also with the stock FPR. Once you have the system in then you should log your afr at wide open throttle and adjust it accordingly - your target should be between 13 and 13.5. I'll post some more info later on today but have a read at this thread regarding the injector flow in the meantime http://4bangerjp.com/forums/index.php/topic,7203.0.html
also you will need to use sparkplugs that are probably 2 numbers colder than stock, and if you don't plan to run an intercooler you might need to retard timing. In case you don't use the Split Second unit or similar you will need a 2 bar MAP sensor, but the mods are extensive to trick the ECU and in the end you are probably better just by using the PSC1.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
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Offline sharpxmen

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Re: 30# injectors
« Reply #6 on: August 12, 2009, 12:17:53 PM »
ok, here's some basics - some numbers could be off but this should be close enough to give you an ideea (for example i am considering 14.5psi at sea level but lots of examples i have seen use 14.7 or 14.69, but as i said just for an example should be close enough).

the ambient pressure at sealevel is 1 bar or 14.5psi - that means when you have a normally aspirated engine the _absolute_ pressure in the intake won't be more than 14.5 psi at sea level (this is when your vacuum/boost gauge would read 0 which is the relative pressure compared to the ambient at sea level).

now, if you plan to use 6 psi of boost as you mentioned (and for 8 the ideea is the same) your absolute pressure in the intake at wot will be 14.5+6=20.5psi and that in turns is  41.4% greater compared to what you had before - based on the info in the faq section of this site your injectors are flowing 17.4lb/hr at a pressure of 39psi so you will need injectors that are around 24.6lb/hr to achieve the same air/fuel ratio at wot (keep in mind that this is a rough estimate, real world would be a little different considering that not all the factors have a linear variation and also account for the fact that once your fpr sees boost the fuel pressure would increase by aproximately the same account). In any case you might want to go a bit higher so let's say you pick an injector that was used on Chrysler 2.2l and 2.5l and the Pontiac 1.8l, Bosch P/N 0-280-150-201 which is rated at 24.55lb/hr @ 3bar or 43.5psi - this injector's flow would be 23.25lb/hr at 39psi (so a little lower than what you need) but if you account for the increase in fuel pressure when you get full boost (let's say you get 39 + 6psi=45, probably not 100% accurate, it depends on how the FPR is built but good enough for an example) - that would give that injector a flow of 24.97lb/hr - very close to what you need and if you keep in mind that you want to go richer with a forced induction engine would be a good point to start - you can use an adjustable FPR and fine tune the final flow based on the air/fuel ratio you get.

All the above would work in an ideal world but before you get there....
Your stock MAP sensor is calibrated for 1bar/14.5psi and from what i recall will give you about 4.75v at 1 bar (zero vacuum reading) and would have a 0 to 5v full sweep (so would give you more than 4.75 if the pressure is higher than 14.5). Once you boost your engine you will need somehow to give the ecu the same information but with an offset of 6 psi in your case - that way by adding the appropriate larger injectors you will get the estimated fuel flow at full boost based on the calculations above. How does it work

stock map varies from a 0v output at absolute vacuum to 4.75v at sea level where your WOT and vacuum reading is 0 (1bar/14.5 psi absolute pressure)
the new map sensor output (whichever way you achieve that) should go from 0 at 0 pressure to 4.75 at 6psi of boost (that would be 20.5 absolute pressure) - that way you just shifted your engine's electronics to work on a different scale - keep in mind that this will definitely not be the real world case scenario but good place to start your fine tuning.

If you go with the PSC1 or FTC1 from split second then you have the luxury of a built in 2bar map sensor and you can adjust the output on the map as you wish to give you the range we just discussed - the PSC also has the nice feature of being able to use the stock calibration (that means the ECU would read the atmospheric pressure when you put the contact on so it knows what is the baseline for your full power, if you use home made MAP that will give you the full range described above then you need a way to tell the ECU what is the current atmospheric pressure for the baseline - but that is another discussion).

if something's unclear in the above let me know and i'll try to explain in more detail

EDIT: i still need to talk about timing, will do another post once i know that this part is clear.
« Last Edit: August 12, 2009, 12:23:32 PM by sharpxmen »
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
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yooperjeep

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Re: 30# injectors
« Reply #7 on: August 12, 2009, 01:17:40 PM »
Okay, I think that I understand. For the most part I either need to come up with some sort of device to re-scale the pressure range for the MAP under boost and interpolate the correct reading to the ECU. This is where the split second device comes in. It will do all of this and also allow you to customize it for optimal performance. From the rough estimates you gave me for injector size, if I want the capability of going up to about 8psi I would be safe with about a 27-30lb injector and just modifying the system with the split second software to account for any difference between the ideal and what I have. Is there any harm in going slightly big on the injector and just modifying the system with the split second software?

Offline sharpxmen

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Re: 30# injectors
« Reply #8 on: August 12, 2009, 11:48:25 PM »
you probably want to be close to the estimate and adjust the fuel pressure for fine tweaking at wot - why i say that: if your ecu does not see the wot and 4.?v (not sure on this one but i'm just guestimating it's somewhere over 4 volt) you will be running in closed loop (the ecu will think you're cruising) so in that case it will use the o2 feedback to adjust the air fuel ratio (so in case your injectors are too big you will output too little from the psc1 to get in open loop) - in that case it doesn't matter what the psc1 gives you, your ecu will try to achieve 14.7 afr by adjusting the injector duty cycle and you will end up too lean under boost. so get it as close as possible and then adjust the fuel pressure to give you the correct flow.
so for 8psi you will get 55% more air
your injector flow should be calculated at 47psi (39 stock + 8 boost) and should be 27lb/hr. now you can account for 10% richer and some adjustments in fuel pressure (you should have an adjustable FPR) - so 30lb/hr between 40 to 47 psi should be close  enough (i added the 10% richer afr since you will have boost) - that gives you a range of 28 to 31 lb/hr both at 43.5psi which is what the factory usually rated the injectors at (make sure you calculate this in case the pressure is different) - and keep in mind that the fuel pressure will help you achieve the full sweep of the MAP from which the ecu will decide what sort of load is your engine at.

but you need to keep in mind that if you go to 8 psi you might need to lower your compression ration and for sure to use an intercooler - with turbos compared to the screw superchargers the air temperature is much higher and in turn the temperature in the chamber will be higher (you risk detonation/knock and also melting your pistons) - in that case you might need to go richer, but that is just to compensate for the higher temp in air charge, it will not give you more power.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
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yooperjeep

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Re: 30# injectors
« Reply #9 on: August 13, 2009, 05:11:54 AM »
Thanks for all of your help. I found a post in the FAQs about injector sizes and ones that might fit. It looks like a T-Bird Super Coupe red top injector does 30#. are these easy to find and will they actually be what I would want? Earlier you said there were a few things about timing I needed to know...want to share?

Offline sharpxmen

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Re: 30# injectors
« Reply #10 on: August 13, 2009, 01:39:25 PM »
Thanks for all of your help. I found a post in the FAQs about injector sizes and ones that might fit. It looks like a T-Bird Super Coupe red top injector does 30#. are these easy to find and will they actually be what I would want? Earlier you said there were a few things about timing I needed to know...want to share?

ok, timing: the advance of the spark is meant to account for the time it takes for the air/fuel mixture to ignite entirely and the goal is to have it fully burning when the piston is at TDC on that cylinder. Now, the colder the mix the slower it ignites, so you need more advance. Same for the rpm, the higher the more spark advance you need and that is because it takes less time for the piston to reach the TDC and therefore you need to ignite it earlier. On most of the new vehicles with an MPFI (and probably all at this point) there is an air intake temp sensor - that sensor tells the ECU what is the density of the air (how many molecules of O2 per cubic feet of air let's say) so it can adjust the mix but also how hot is the air and resulting air/fuel mix to adjust the timing - the hotter it is the faster it ignites so you need less timing. But keep in mind that this does not mean that is better to have it hot - once the temp rises you basically get less oxygen per cycle, so that accounts for less power and also (and this is more important) the risk of having the mix auto-ignite or instant detonation which translates into ping/knock that you can sometimes hear. The lower the octane the more likely to have knock, so for lower octane you have to retard the spark more.

So,
1. with a turbo/supercharger you will need less ignition advance because the mix is hotter and the pressure in the chamber is higher (also helps the mix to burn faster) - this will not affect your power when you retard the timing.
2. you run the risk of detonation (which is random most of the time) and then you will need to retard the spark even more, this is mostly due to too high temp in the chamber or too much boost for the engine (which in turn is related to the temp and too muck pressure in the camber) - this will require even more timing retard but unlike #1 this will hurt the power output.

- to address number 1 and 2 there are a few options
  a. you will need a timing retard module if your ECU will not adjust it properly or too much due to the increase in air temp - you will have to test this once you have your system completed, but a fair guess would be that you most likely need one. ***Now, if you do end up with a timing retard module of some sort i suggest that the Air Intake Temp sensor to be moved ahead of your turbo - some companies do that to keep the ecu and boost timing control from fighting each-other (both trying to achieve the same thing, you'll end up with too much spark retard/too little ignition advance).
 b. you most likely need an intercooler to address #2 (in the winter you could get away w/o one, but if it's summer you will see what i mean).
 c. Use cooler heat range spark plugs - the cooler the heat range the faster the sparkplug removes the heat from the chamber
 d. lot of people decide to increase the fuel volume and therefore get the air/fuel ratio to low values to lower the temp of the mix - but that is just going to hurt your mileage, there are no benefits other than addressing the knock issue
 e. you can also add octane booster, that would help but it get's pricey since you have to add it every time you put fuel in the car
 f. run water injection that kicks in at certain air intake temp and boost - water is free but you need a tank for it and keep adding so you don't run out (and the idea is the same with increasing fuel drastically but in this case it's cheaper).

the advantage with turbos is that it only kicks in at higher rpm, so less range to actually worry about ignition advance, the disadvantage is that the air is hotter.

hope i covered most of the issues, could've missed something but feel free to ask if you have any questions.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
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st.chevrolet

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Re: 30# injectors
« Reply #11 on: August 13, 2009, 03:29:54 PM »
I run the Split Second PSC1-002 which is a air/fuel calibrator. I tried running a GM 2 Bar MAP, don't work, Jeep ECU seems unable to read it. I run a water/methanol injection system and use winter windshield washer fluid, I have no issues with timing and do not run an intercooler. I can also run the lower octane fuel.

Offline sharpxmen

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Re: 30# injectors
« Reply #12 on: August 13, 2009, 04:28:00 PM »
just out of curiosity why did you install the water injection? what are you using to activate it (wot, do you have a switch or some other form of control) and how often does it kick in?

imho, for a 9.1:1 CR, 8psi, regular pistons - should be at least intercooled (if not water injected like you did). Could get away with ecu + AIT sensor to adjust timing by itself but will not be the best power output but since you are running the turbo you have the info first hand.

the 2 bar map is not going to work out of the box, like i said in this thread 3rd or 4th post (http://4bangerjp.com/forums/index.php/topic,7292.msg53973.html#msg53973) - is not going to be plug and play unless you run 1 bar boost (14.5 psi boost) and match your injectors to flow the required amount of gas, otherwise if you are at 10psi let's say you need to adjust the output for that max pressure/voltage (exactly like your PSC1 does and it uses the 2 bar map internally) - the advantage with the PSC1 is that it uses a fuel map so you can have different outputs based on rpm and pressure and not be 1 dimensional like the MAP sensor (which only varies by the pressure), it can be done though but not with the same results - with the PSC1 or FTC1 for example if you run 6psi of boost the 2 bar map default output would be around 3.3 to 3.4 volt which is too less, you would need to modify that by another 1.4volts or so - in that case the fuel map cell in PSC should be set to 15.6 (give or take, more likely on the give side).

'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
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st.chevrolet

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Re: 30# injectors
« Reply #13 on: August 14, 2009, 01:21:41 AM »
just out of curiosity why did you install the water injection? what are you using to activate it (wot, do you have a switch or some other form of control) and how often does it kick in?

imho, for a 9.1:1 CR, 8psi, regular pistons - should be at least intercooled (if not water injected like you did). Could get away with ecu + AIT sensor to adjust timing by itself but will not be the best power output but since you are running the turbo you have the info first hand.

the 2 bar map is not going to work out of the box, like i said in this thread 3rd or 4th post (http://4bangerjp.com/forums/index.php/topic,7292.msg53973.html#msg53973) - is not going to be plug and play unless you run 1 bar boost (14.5 psi boost) and match your injectors to flow the required amount of gas, otherwise if you are at 10psi let's say you need to adjust the output for that max pressure/voltage (exactly like your PSC1 does and it uses the 2 bar map internally) - the advantage with the PSC1 is that it uses a fuel map so you can have different outputs based on rpm and pressure and not be 1 dimensional like the MAP sensor (which only varies by the pressure), it can be done though but not with the same results - with the PSC1 or FTC1 for example if you run 6psi of boost the 2 bar map default output would be around 3.3 to 3.4 volt which is too less, you would need to modify that by another 1.4volts or so - in that case the fuel map cell in PSC should be set to 15.6 (give or take, more likely on the give side).



I run water/methanol injection for a number of reasons; chemical intercooling, works at any speed, inexpensive octane booster, detonation control, just to name a few. I control it with an adjustable boost activated switch which obviously kicks in whenever I reach my activation pressure (climbing the Coquihalla connector its always on). As I mentioned in my thread, I set out to turbo my YJ as cheaply as possible. So I tried the GM 2 Bar MAP, which as I mentioned the Jeep ECU cannot read. I also tried map clamps and check valves and bleeders but I wanted my setup to be smooth and reliable, hence the Split Second PSC1-002 (ECU has no idea its running a forced induction engine).The PSC1 is the most expensive part of my setup but well worth the $, I have run it for approx. two years now and am quite familiar with how it works and how to program it. IMHO the OBD1 system, along with the PSC1, Hesco AFPR and a H20/Methanol injection system, there is no need for injectors larger than 30lb or timing retard. My YJ is my DD and except for the power it starts, idles and runs like it did without the turbo even when its -25*to -30*F.
« Last Edit: August 14, 2009, 01:23:01 AM by st.chevrolet »

yooperjeep

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Re: 30# injectors
« Reply #14 on: August 14, 2009, 05:01:46 AM »
St. Chevrelet, Did you do a write up on how you set up your water injection system on here? I read your turbo build but didnt really see anything about the water injection (I could have missed it). So given that I am pretty content on buying the split second system, I just want to make sure I have a pretty good idea of everything I need to begin gathering parts for my turbo build:

Turbo (Already have from a Volvo S40)
Split Second  PSC1
Hesco (other makers?) Adjustable Fuel Pressure Regulator
30# injectors
Electric Fan conversion
Water injection (I dont really want an intercooler if I dont need one)
Misc plumbing and exhaust

If you can think of anything else just let me know as I am pretty new to all of this (I have only owned my jeep for about 3 weeks). Thanks again for all of your help!