Sooo injector size

[justinsstang]

My HP goal is 600-650 rwhp (maxing stock block) with a twin turbo so lets guesstimate that as 700-750 crank hp. We'll just say 750 for the purpose of making sure I have enough injector.

So if the correct equation is (750 hp x .5 BSFC) / (8 inj x .8 duty cycle) that's 375 / 6.4 leaving me with a 58.59lb/hr injector at 80% duty cycle, and I'll obviously be rouding up to 60lb/hr.

So my question is why do I keep getting recommendations to get ID1000s? Wouldn't that be way too much injector for my application, or am I doing the equation totally wrong?

 

[BruceH]

The 2013 GT500 injectors would be perfect and quite a bit less expensive. Too much injector applies to non adjustable return systems and injectors that don't handle low pulse widths very well. Modern day returnless fuel systems can adjust fuel pressure and subsequently fuel injector output via the tune.

 

[justinsstang]

The OEM 13-14 GT500 inectors are 57LB/hr right?

See I think that's enough injector as well. The injector would be right at the 80% duty cycle which from all of what I've ever seen is right where you want it to be at.

Just really curious why I've been seeing so many ID1000 (95.2 lb/hr?) recommendations. It seems like a waste of resources to drop that much $ on such a high dollar injector that will only see a 49-50% duty cycle.

Unless I'm messing up math somewhere, I wouldn't put it past myself, but I guess I'm just looking for a cheaper route than those $900 injectors lol (of course I've seen them used for way less but... it is what it is).

 

[01yellerCobra]

Are the recommendations for guys running E85? Those set ups need bigger injectors.

 

[justinsstang]

That might have been the case. I don't think I want to run E85 due to availability in my area. Leaving town could be a problem finding another station with E85. Would prefer to stick to 93 so I'm gauging injector for that.

 

[T-Neck]

I make 620 and run 47's. Bout 88% duty cycle. Never leaned out, not once.

 

[konablue11gt]

thing is yes you will be fine now...but like so many on here soon after you get the hang of the car your going to want more and then your going to buy new injectors cause what you have wont support more. so pay now or later its up to you.

 

[cyclerick]

I have the ID1000s on my 2011 GT with Paxton and around 620 rwhp. According to my tuner, the IDs are great to tune and the 1000s give you room to grow.

 

[JeremyH]

My HP goal is 600-650 rwhp (maxing stock block) with a twin turbo so lets guesstimate that as 700-750 crank hp. We'll just say 750 for the purpose of making sure I have enough injector.

So if the correct equation is (750 hp x .5 BSFC) / (8 inj x .8 duty cycle) that's 375 / 6.4 leaving me with a 58.59lb/hr injector at 80% duty cycle, and I'll obviously be rouding up to 60lb/hr.

So my question is why do I keep getting recommendations to get ID1000s? Wouldn't that be way too much injector for my application, or am I doing the equation totally wrong?

That formula needs pressure as well to get an accurate result.

Other things like driveability, idle quality, gas mileage etc come into play when choosing injectors. I get better driveability and fuel mileage with my bosch 1000cc injectors than I did with the 47's 60's or 80's I use to run.

That's another point I'm on my 4th set of injectors, that's why guys recommend getting the last set you will need, in the end its more cost effective.

There's no such thing as going too big on the injectors.

The OEM 13-14 GT500 inectors are 57LB/hr right?

See I think that's enough injector as well. The injector would be right at the 80% duty cycle which from all of what I've ever seen is right where you want it to be at.

Just really curious why I've been seeing so many ID1000 (95.2 lb/hr?) recommendations. It seems like a waste of resources to drop that much $ on such a high dollar injector that will only see a 49-50% duty cycle.

Unless I'm messing up math somewhere, I wouldn't put it past myself, but I guess I'm just looking for a cheaper route than those $900 injectors lol (of course I've seen them used for way less but... it is what it is).

Don't forget guys, the injector ratings as we know them all go out the window for the coyote. Ford injector flow ratings are based on the pressure rating which is 39.15 psi and GM uses 43.5. The Coyote has a mechanical returnless setup that doesn't maintain delta or pulse modulate the pump. It has a mechanical regulator in the hat that maintains a 55psi base pressure.

Hence why guys can make 600rwhp with a 47lb injector. It's actually flowing closer to 60lbs. A 60lb injector is actually a 72lb etc.

Are the recommendations for guys running E85? Those set ups need bigger injectors.

I would go straight to the bosch 1000cc injectors for e85. No smaller.

 

[01yellerCobra]

I would go straight to the bosch 1000cc injectors for e85. No smaller.

Yeah. If I was going to run E85 I'd go with the 1000's. I was mentioning it since the OP was confused. Just an idea.

 

[BruceH]

The OEM 13-14 GT500 inectors are 57LB/hr right?

See I think that's enough injector as well. The injector would be right at the 80% duty cycle which from all of what I've ever seen is right where you want it to be at.

Just really curious why I've been seeing so many ID1000 (95.2 lb/hr?) recommendations. It seems like a waste of resources to drop that much $ on such a high dollar injector that will only see a 49-50% duty cycle.

Unless I'm messing up math somewhere, I wouldn't put it past myself, but I guess I'm just looking for a cheaper route than those $900 injectors lol (of course I've seen them used for way less but... it is what it is).

It depends. IMO you will get that recommendation from all the cool kids who haven't had the power you are going after. The next group would be tuners who want to sell them to you as there is a profit factor involved with the ID map pricing.

I'm not saying there is anything wrong with them and if they are in your grand scheme of things then buy once and cry once. However, if you are going to stay at your predicted levels for awhile or forever then it might make more sense to buy the 13 GT500 injectors and use the savings somewhere else.

I've run a variety of injectors and setups at a variety of hp levels. The first thing I'd say is go with Bosch. Like I said in the previous post the things we hear about injector sizing don't really apply to modern vehicles. Some of it does. An example would be my motor with the DOB setup. I ran E85 at 585rwhp with a returnless duty cycle of 86%. This with the 13 GT500 injectors (under $300 new) and gt500 fuel pumps with a bap. The old formulas would say that I could never support that level, but I did.

If you have the money go with flow matched injectors. I've had an excellent experience with the paint dot marked Bosch Racing. A set of 1000cc injectors will run you about $600.

 

[justinsstang]

When it comes to driveability, idle and gas mileage how exactly does the injectors act at different sizes/power levels?

Bigger injectors = better in all 3 categories?

6psi is going to put me just over 600rwhp with the MT82 and the most I'd ever try stock block without doing oil pump gears is 650rwhp, which would probably be nearly made with 7psi.

How would the Bosch 1000cc injectors act in those categories at that power level compared to a 60lb injector? These for example: http://www.americanmuscle.com/mustang-ev6-60-injectors.html

Keep in mind, I'm not running E85, 93 only.

Edit: And where do you see the Bosch 13 GT500 injectors for the price you mentioned, weighing all options.
I also plan on running a 20amp BAP like you did, with S&H wiring upgrade to lower duty cycle.

 

[Mystickeith50]

Here's why I went with 1000s....you say oh, all I want is 600. Then 600 gets boring, now I want 700...now 700 gets boring. Point is this time around I wanted to buy 1 injector not 2 or three sets. I never thought I put a blower on this car..or a motor but I did. Injectors will be good for whatever I want to do with it.

 

[BruceH]

When it comes to driveability, idle and gas mileage how exactly does the injectors act at different sizes/power levels?

Bigger injectors = better in all 3 categories?

6psi is going to put me just over 600rwhp with the MT82 and the most I'd ever try stock block without doing oil pump gears is 650rwhp, which would probably be nearly made with 7psi.

How would the Bosch 1000cc injectors act in those categories at that power level compared to a 60lb injector? These for example: http://www.americanmuscle.com/mustang-ev6-60-injectors.html

Keep in mind, I'm not running E85, 93 only.

It's going to depend on low pulsewidth linearity. I don't think you are following how psi affects flow. Not all injectors flow the same so to compare max flow numbers only isn't a good idea if driveability is a concern. Driveability is going to depend on a number of factors. One of which is low pulsewidth linearity.

The bosch 1000cc injectors are going to be far more driveable than the 60's imo. Do some research on the linearity characteristics. You will find the SD 60's by searching for Continental as they are the manufacturers.

 

[JeremyH]

When it comes to driveability, idle and gas mileage how exactly does the injectors act at different sizes/power levels?

Bigger injectors = better in all 3 categories?

6psi is going to put me just over 600rwhp with the MT82 and the most I'd ever try stock block without doing oil pump gears is 650rwhp, which would probably be nearly made with 7psi.

How would the Bosch 1000cc injectors act in those categories at that power level compared to a 60lb injector? These for example: http://www.americanmuscle.com/mustang-ev6-60-injectors.html

Keep in mind, I'm not running E85, 93 only.

Edit: And where do you see the Bosch 13 GT500 injectors for the price you mentioned, weighing all options.
I also plan on running a 20amp BAP like you did, with S&H wiring upgrade to lower duty cycle.

Like Bruce mentioned, it has to do with injector technology/design, most of the relatively "smaller" injectors 39,47,60,80's were designed a long time ago and aren't as robust, they don't operate as well at higher pressures either. Back then they just went to larger reworked valves to flow more, and still had a pencil style stream which leads to poor atomization and combustion, poor control and performance etc. Every time the injector is pulsed that fuel pressure behind it and pintle valve size will affect the minimum amount of fuel that is actually pulsed. So at idle and part throttle ie low pulse width injector control will suffer which in turn affects drive ability and gas mileage. My gas mileage was so horrible and the car stumbled with 80's down low. I'm talking 7-15mpg difference city/hwy and would stumble even when fully up to temp some times.

The newer larger injectors ie bosch 1000cc are revised design. They have mutli-orfice tips with better spray patterns and atomization. They retain stock size pintle valves and have a much more consistent/linear operating range with a more dynamic range of control. So they cold start, idle, drive and perform like a stock injector but will support 3-4 times the flow. Also they are rated to higher base pressures while still maintaining control, they can run up to 6-7bar (90-100psi). Where as older injector designs are only rated to operate at 3-4bar. Making them also harder to control and tune on a boosted cars since fuel pressure has to increase so the injector can overcome boost in the manifold and still flow properly. Bosch makes smaller injector as well with this technology, the older designs are SD, lucas, Delphi and some frpp injectors etc. Your link is to SD 60's they are a good injector, I ran SD 60's at 39psi and they operated well. They are not as robust as bosch though.


Ford jacked up the price on the 13 GT500 57'lbers IIRC. They will also require injector spacers as they are ev14 style.

 

[JeremyH]

Here's a cool video showing how different brand and style injectors operate at different pressures and how well the spray patterns atomize the fuel.

 

[hamish]

Don't forget about the spray angles.
Not all injectors will spray straight.
Very curious about the 2013-14 GT500 injectors in a stock 3v injector location?
Someone here must be running them.
BruceH?

 

[justinsstang]

I could lose 7-15 mpg by going with those 60lb injectors over the Bosch 1000? Lol that's nuts if that's true. Clearly the Bosch 1000s are the winner if that's the case...

Would want to buy used though. Will start looking soon, should have nearly double the income I have now in a few weeks (as long as everything works out).

Is there anything else I should know about the Bosch 1000 injectors or does all this about sum it up? At least the Bosch is way cheaper than those ID1000. Couldn't see myself spending close to $1000 on injectors

 

[BruceH]

Don't forget about the spray angles.
Not all injectors will spray straight.
Very curious about the 2013-14 GT500 injectors in a stock 3v injector location?
Someone here must be running them.
BruceH?

I have run them and had no issues. IMO spray angle is what some tuners blamed for their lack of plotting intake valve opening and adjusting accordingly with aftermarket cams. It's just an opinion and I could be wrong but the thing is that I haven't had issues with the injectors that are supposed to have "bad angles" unless the stock injector timing was used with an aftermarket cam.

If the cam profile changes intake valve opening events then it must be accounted for in the tune. If it isn't accounted for things like stumbles, raw gas smell out the exhaust, and poor mpg are the result.

A good example would be FRPP Hot Rod cams. Ever wonder why some people have great experiences with them and others curse them? They change the intake valve opening by 30 degrees iirc. This means that if the stock fuel injector timing is used fuel will be spraying on an open valve. Fuel should always spray on a closed valve for reasons I'm not going to type out, lol.

A good read on this would be the Greg Banish book "Engine Management Advanced Tuning". The book covers some important internal combustion motor principles besides covering how to tune to maximize those principles.

 

[JEWC_Motorsports]

Are the Bosch 1000's e85 compatible?