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Thread: Big Injectors for Corn
11-21-2019, 10:53 AM #1
Big Injectors for Corn
So we talked about them in another thread but wanted to start this one so all info can be in one place. I have the FRPP 80s currently I am about to pull for bigger injectors. These will be run off a Stand alone (MS3pnp). Ed you mentioned the denso FIC 2000. I was looking all over the Fuel Injector Clinic (FIC) for them and only found FIC 2150s. Then after googling I found Fuel Injector Connection (FIC) FIC 2000. So there are two FIC. I really don't want IDs. So what would be the best route for injectors that are a healthy side and can run E85 and maybe C85 or what ever the new latest greatest mix of corn and race gas and not expand and clog?
This is a street car so drivibilty is most important.
11-21-2019, 11:06 AM #2
11-21-2019, 11:20 AM #3
All of it! Maxed the 80s out in the 800rw range so north of that. in all seriousness no clue what the end game numbers will be. No cars like mine to compare to and some of these numbers I see guys claiming on a lot less mods are insane. I have bought so many injectors over the years. I just want to do it once more!
Last edited by GodStang; 11-21-2019 at 11:27 AM.
11-21-2019, 11:26 AM #4
My tuner uses these a lot for the cars he builds so for comparison here's the one's I bought:
Making 900hp on E85, through three mufflers, auto transmission, using three 340 pumps the duty cycle on these injectors are right at 70%.
Last edited by KEVINS; 11-21-2019 at 11:29 AM.
11-21-2019, 11:32 AM #5
11-21-2019, 11:45 AM #6
I would imagine the screw will require more HP to drive it and it would probably depend on the boost it was trying to force down the throat of the motor. The main HP differences between our cars may be the exhaust and possibly transmissions...
I'm guessing that if I ran open exhaust mine would be making a over 1000 to the tires..
Last edited by KEVINS; 11-21-2019 at 11:49 AM.
11-21-2019, 01:10 PM #7
11-21-2019, 01:11 PM #8
The key to injector survival on any of the alcohols, Josh, is the use of stainless internals so they become impervious to oxidation from any moisture that the fuel may be carrying. The other important consideration, easier to achieve, is the use of alcohol resistant o-ring seals wherever they are used in the fuel system. It goes without saying that the fuel lines should be the teflon lined variety for protection against bladder deterioration. Viton is the preferred material for o-rings that will be used for sealing with either of the alcohols. I have attached a highlighted material properties sheet for Viton to the end of this post with the alcohols portions highlighted.
Injector sizing has historically been a matter of attempting to squeeze the most power out of an undersized injector as we can. Because, over the years, we regularly ran into flow capacity ceilings in terms of what was commercially available to us the approach frequently taken to increase injector flow was using a higher base pressure to increase the flow through the injector. While this approach worked when larger injectors were unavailable it is not necessary with todays injectors and presented problems then and now when implemented. Today, as you know we can buy almost any size injector over the counter.
Using smaller than required injectors and then boosting base fuel pressure to add volume has several undesirable side effects. With boost referenced pressure regulators it is necessary to add our maximum boost pressure to the base pressure to get the fuel rail pressure the engine will demand for proper fueling. Lets say we only increase our base pressure to 50 or 55 psi. If the supercharger produces 25 psi of boost that means the fuel rail pressure needs to be 50 or 55 psi plus the 25 psi offset for boost. That puts fuel rail pressure at 75 or 80 psi.
At a 75/80 psi fuel rail pressure you are substantially changing the characterization of the fuel system. Just for starters a 75/80 psi fuel rail pressure requires 3 to 5 psi more pressure at the pump to create the desired fuel rail pressure you are seeking. This raises the head against which the pump must pump. As you raise head, pump volume decreases in a rapid non linear fashion. In addition the pump will draw more amperage (not voltage) to maintain the higher line pressure. The increased amperage draw reduces power throughout the car's electrical system. If / when it affects the ECU power. the ECU begins to behave unpredictably.
In addition to the electrical mischief there are several mechanical issues that are significant. The two at the top of the list are the fuel pump safety relief activation and injector dead time differences attributable to higher fuel pressures holding the pintle on the injector shut longer when using the same activation voltage and current. This has the effect of decreasing injector flow characteristics. The fuel pump safety relief is a fail safe that the pump manufacturer puts into the pump to prevent damaging the pump by exposing it to high pressures for extended periods of time. When the fuel pump's internal pressure relief is activated the first time it never correctly seats again! The lack of correct seating provides an internal (to the pump)'leak that decreases the pump's flow capacity by the volume bypassed at the pump's internal pressure relief.
To be fair the pump manufacturers have begun to offer pumps with higher blow off thresholds to circumvent this problem. Here is an example of a TI Automotive pump, offered by Fore Innovations, that TI Automotive has raised the pressure relief blow off high enough they rate the pump for operation at 87 psi, click here => Hi Press TIAuto Pump. When you read the specs for the pump you notice each pump needs to be fused for 25 amps! The higher amperage draw is attributable to the higher operating pressure. The flow increase provided by the additional 12 psi is negligible and the wear and tear on both the electrical and hydraulic components of your fuel system is significant.
Then of course there are the financial considerations. You have lived this particular facet of the injector sizing merry go round in spacdes, Josh. If you buy ID injectors you ar essentially paying $1 per cc of injector flow. That translates into $800 to $1500 (approximately) per injector upgrade/ change.
It doesn't take very many of these events to equal the price of a new blower — and that is after you bought the blower!
Injector design and technology has come country miles in the last 10/15 years. We have high impedance injectors available today that previously could not even be duplicated with commercially available high flow low impedance injectors. The big benefit for guys like us is the ability to upgrade to an injector we will likely never have to change out for increased flow demands ever again! This turns out to be a big deal when you look at the price of big injectors. Even better these big injectors have excellent low speed (small pulse width) performance which means they actually allow us to idle an engine below 1000 rpm.
All injectors are flow rated ar 3 BAR (43.5 psi). Ford runs their fuel injection systems at 2.7 BAR (39.15 psi). This has multiple benefits from reduced current draw, more stable electrical power to the ECU, reduced injector dead time etc. Lots of good Karma. By using a 2000 to 2200cc injector at 39.15 psi base fuel system pressure you get all the goodness Ford was engineering into their OEM fuel systems and very importantly these injectors will likely become the last ones you ever buy — ever! AJ runs double 2200 cc injectors per cylinder and the engine will idle comfortably at 1000 rpm. It has idled reliable as low as 850 rpm with both injectors operating at idle! His engine fuel wise is similar to yours. He runs methanol instead of E-85 but the engine's fuel demands are otherwise quite similar.
There is lots of upside and no significant downside to using the big injectors. Your ECU will correctly drive the injector based on the engine loading it calculates from its electronic eyes — the various engine sensors. The only potential downside might be a slight price premium over a smaller injector. Today that pricing premium has all but disappeared making the purchase a wash pricewise.
11-21-2019, 01:36 PM #9
There is a solution. It involves using Brake Specific Air Consumption (BSAC) and works for all types of supercharging. That I am aware of, I have never seen this anywhere else on the internet except on ModFords. An older Admin (Black2003Cobra) first began to promote this approach before I arrived on the site. I have used the approach for nearly 50 years to size fuel system components and tune race engines with both mechanical and electronic fuel injection. I published a calculator for this almost 5 years ago on this site. The current version is 2.11 and is available in the Terminator Table of Contents (TToC) under the fuel system section. It is the fourth item down the list. I will be publishing an updated version around New Years that is more conservative on the minimum AFR's.
The beauty of BSAC vs BSFC is you do not need a dyno to know the BSAC. All you need to know is your blower size and blower overdrive. The calculator can figure the BSAC from this. This is what Page 1 looks like;
This is Page 2 where the calculator does the injector sizing calculation;
And this is Page 3 where you can specify fuel and look at the conservative safe line in the sand;
A lot of times we need to convert from one system of measurement to another. Page four provides those conversions;
The page three above has the new more conservative AFR suggestions and the upgraded version of the calculator will have additional conversions between unit systems. The upgraded version should be up around New Years.
Before using this tool or the upgraded too be sure to read the instructions in the TToC thread.
Last edited by eschaider; 11-21-2019 at 02:03 PM. Reason: Fixed broken pic link
11-21-2019, 01:55 PM #10
11-21-2019, 02:03 PM #11
I run the ID1700X injectors, I was told they would be good to around 1300whp. I had ID2000 but they were locked up by the E85
11-21-2019, 02:09 PM #12
Ya I went to the dyno to get an idea on what I had to work with and I was turned away because they knew my 80s would fail.
Ed thank you for repeating all the info you gave in the other thread back to this one for future people researching. Now that I am safe using 2000cc size injectors. Wanting to buy my last set having had 5 sets on this car already which ones are all good:
ID 2000 for $2K
FIC 2150 for $1600 ($150 off next week)
Denso FIC 2000 for $1200
I have PTFE lines and I can swap out O-rings. I am looking hard at the FIC 2150 just not sure if they can handle the E85 and the C90 or what ever that new fangle fuel is?
11-21-2019, 04:45 PM #13
ID2000, FIC 2150 and literally all the 2100cc injectors except the siemens deka 220's are all re-badged Bosch 210's. I run Bosch 210's and they idle and drive great, but in all reality they work best with a standalone computer. This is where I tell people to spend the money on the standalone vs the big money ID injectors. It's much better money spent when you start approaching and eclipsing 4 digit power levels.
Last edited by badcobra; 11-21-2019 at 04:49 PM.
11-21-2019, 06:33 PM #14
You are entirely welcome to use any of the toys on the site here, John (am I right?). The next rev, that I want to get out after New Years, corrects some rounding errors, cleans up the fuel tables page #3 with more conservative don't go leaner lines in the sand and adds to the conversions on page four so you don't need to go searching on the net for a particular conversion factor.
You are right about the dual 700# Billet Atomizers — unless of course it is a Blown Alcohol ProMod style engine and then the engine's appetite for fuel takes a fairly impressive step upwards. BTW the calculator can be used with turbo's by just using a large displacement for the blower and adjusting pulley diameters to get the boost you are targeting. Once you have the boost modeled correctly, the injector sizing just falls out into your lap on page #2.
I am considering adding a flywheel horsepower field to show the potential power the engine is capable of producing with the particular volume of air being processed by the engine before parasitic losses like a twin screw blower. It is a good indicator of how well built, tuned and operated an engine actually is. A lot of times the urge to buy a new set of the current double throw down billet heads can be suppressed when you realize you are basically at or near a 95% to 100% conversion factor for the amount of air (and fuel) you are currently processing through the engine. Additional horsepower will typically be found lurking elsewhere in places like cam phasing and cam profiles or higher engine speeds or better optimized fuel, air and spark maps in the ECU. In the FWIW column higher engine operating speeds can make a compelling argument for better heads if the current heads are performing at or near their peak at current engine speeds.
11-21-2019, 07:19 PM #15