Injector size for FP series

[Splitpi]

Walbro 255 will only flow enough to feed 1000cc injectors @ 80% Duty Cycle ideally. If you have big dreams of feeding that massive turbo to its fullest you need a better fuel pump, filter and lines.

If 400 hp is all you want then 1000's and a 255 w/ FPR is perfectly fine.

 

[AuntiesTSI]

I already have the upgraded lines siittin in my garage too, just not installed. I'll probably search around and read a bit more before I decide on which injectors to go with and the inline pump idea. Thanks guys.

 

[NewTurboTuner]

1600's! You guys are nuts! (I assume its your street car.... IS it?)
The spray pattern, and atomization of a big injector won't be nearly as good, as with a smaller injector. The bigger you go the less efficient it is. You'll have to spray a little more gas to make-up for the poor efficiency. It'll make for bad fuel economy, be hard to tune, and it's way over kill for 400 street driven pony's. Only go as big as you need to, or maybe a little bigger. 1000cc will do 500awhp easy. 1600's are silly unless you're planning to make 700hp plus.

EDIT/ADD :
I run a walbro255, and don't worry about it failing. I personally know many people running these successfully with Zero reports of problems. I've run them for years, in 4 of my different cars with O probs. I put down 433rwhp/481rwtq on my STOCK LS1 F-Body Fuel Pump running rich, and The Walbro255 is THE standard upgrade for those cars. In the LS1 world you upgrade to a Walbro255 if you want to make over 500hp safely. (why you say its only good for up to 500hp baffles me?) I haven't heard anything on here about it being bad. I don't think every vendor on here would sell a product that is known to fail often (If I search I'm sure I'll find some failure cases) But some sort of failure happens to nearly everything.

80% injector duty cycle is all you want. Go over 85%, and you're asking for trouble.

 

[AuntiesTSI]

It won't be my daily driver but it will most definately be street driven as often as possible Nebraska weather permitting. Also given the fact that the nearest tracks are in Kearney or KC, both over 2 hours away, it won't see too much track use.

 

[Splitpi]

I already have the upgraded lines siittin in my garage too, just not installed. I'll probably search around and read a bit more before I decide on which injectors to go with and the inline pump idea. Thanks guys.

Also get a high flow fuel filter. I believe the stocker will hinder fuel flow at such volumes. Good Luck, I think you have gotten some great oppinions to help you make a decision.

 

[jrpmp69]

If you think 1600's are too big for your goals, I would go with at least the 1000cc's, that way you dont have to worry about having to upgrade your injectors any time soon.

 

[Caithness]

1600's! You guys are nuts! (I assume its your street car.... IS it?)
The spray pattern, and atomization of a big injector won't be nearly as good, as with a smaller injector. The bigger you go the less efficient it is. You'll have to spray a little more gas to make-up for the poor efficiency. It'll make for bad fuel economy, be hard to tune, and it's way over kill for 400 street driven pony's. Only go as big as you need to, or maybe a little bigger. 1000cc will do 500awhp easy. 1600's are silly unless you're planning to make 700hp plus.

EDIT/ADD :
I run a walbro255, and don't worry about it failing. I personally know many people running these successfully with Zero reports of problems. I've run them for years, in 4 of my different cars with O probs. I put down 433rwhp/481rwtq on my STOCK LS1 F-Body Fuel Pump running rich, and The Walbro255 is THE standard upgrade for those cars. In the LS1 world you upgrade to a Walbro255 if you want to make over 500hp safely. (why you say its only good for up to 500hp baffles me?) I haven't heard anything on here about it being bad. I don't think every vendor on here would sell a product that is known to fail often (If I search I'm sure I'll find some failure cases) But some sort of failure happens to nearly everything.

80% injector duty cycle is all you want. Go over 85%, and you're asking for trouble.

Naturally aspirated cars run leaner for the same power outputs. The BSFC estimate for a turbo car is .6 while it's .5 for NA. The F-bodies need less fuel output for their 500 hp so the pump is good for more. 90 percent duty cycle or higher is fine with modern injector technology. Some OEM cars run injectors to 95 percent in the factory tune. I would shoot for much lower duty cycles if I was buying new injectors, though, to give me more head room. Something in the 70 percent range.

 

[SkURTnDSM92T]

DSM Link isn't exactly for the noobie tuners. You have to know what you're doing. Punching in numbers and not knowing how the engine should react is just stupid. Read up. Pick up "How to Tune and Modify Engine Management Systems" by Jeff Hartman. That should help you get somewhat of a grasp on the Link, and let you ask the right questions.

And yes, plenty of people have sucessfully tuned 1600cc injectors for daily use. You just have to know what you're doing.

Agreed, its not for "noobie" tuners...most of the time, you can get a lot more done here on the forum by being constructive, giving solid information, and siting all sources. We are all on here because we like cars, and we like to learn how to make them run as best as possible. We are not around here to swing our E-dicks around... That being said, I know about tuning practices etc.

Thank you for answering my question in regards to IDC..I didnt even think about the atomization type issues that come with big injectors. The 80% cut off for IDC efficiency is what I was looking for. I will most likely start with something a little lower so i dont max them out when i buy them though...

I plan on running my Walbro 255 LPH, a Bosch -044 inline, and most likely 1000CC injectors with DSMlink.

 

[jrpmp69]

I ask the question to someone I know has the 1600cc injectors on his DD talon and this was his response:

Quote:
Originally Posted by trboeclpse98
Are 1600cc injectors hard to tune at low IDC's?


Yes.

They are not good street injectors at all. They stumble constantly at low IDC's. They still stumble even when i used E85 when IDC went up.

Hope it helps in your decision.

 

[AuntiesTSI]

Wow, that last comment helps alot with my decision, looks like I'm doing 1000's.

One last thing, I already have the ugraded -6 line from the tank to the filter, which is an aftermarket Slowboy, and from the filter to the rail. I also have a Buschur FPR and the 255lph, so does that sound pretty good for my goals??

 

[jrpmp69]

^Are you using an OEM or aftermarket fuel filter?

With an inline 10 micron billet fuel filter and -6AN lines your good to about 600hp.

 

[AuntiesTSI]

I have a billet with the 10 micron screen.