What's the largest fuel injector you LD9 guys have got to idle perfectly fine?

I'm talking about larger than 750cc injectors. I'm looking into some 1600cc squirters. I would like some people to chime in, on if you heard or know or have done tunes utilizing big arse puppies. I'm going E85, if anybody is wondering.

(side note: I'm back in the game)


-Trailblazer SS - not so custom 6.0L - custom intake - custom tune
- (1) 2.4L on an engine stand (1) blown trans (2) good quad trans (1) eco trans = party

I know many have done 1000 with no issue. Beyond that I am unsure.



My Cav
I give up...
i'm buying a VW those people love trees, so they should love eachother too... "Andy"

i hope someone comes in with confirmation of 1200 and 1600cc.


-Trailblazer SS - not so custom 6.0L - custom intake - custom tune
- (1) 2.4L on an engine stand (1) blown trans (2) good quad trans (1) eco trans = party

chris, aka sweetnessGT got 1000's to idle w/ hpt.

I know this does not answer your question, but I would not think there is a limit. Reason I say this is you can always go into the idle fuel files and lower the fuel. Using a wideband it might take some time, but should not be a problem to make them idle fine.



FU Tuning

When swapping injectors, it is simply an equation you use, plug in the numbers and play from there. Now Going to 1600 might be some resolution issues IF any.

ya just like john said, if when doin the math to get the 1600's to run bring the constant too low u can always go into the fuel tables like idle and mess with that to try and smooth it out. u may just have to play with it to see what u can do, i myself have not heard of anyone goin that big yet but that doesnt rule it out. good luck cant wait to see how it goes

K. Vega,Now With Vitamin Boost wrote:When swapping injectors, it is simply an equation you use, plug in the numbers and play from there. Now Going to 1600 might be some resolution issues IF any.

I know how to fiddle with the injector constant, and then after that is just messing with the fuel cells down low.

I just wanted to know if anybody tried running big injectors and had issues. Like them just being a bit bitchy to behave right.


-Trailblazer SS - not so custom 6.0L - custom intake - custom tune
- (1) 2.4L on an engine stand (1) blown trans (2) good quad trans (1) eco trans = party

i dont there are many high powered js running around here, i swapping to 1000cc this next time out, but on a side note with running e85 wouldnt the 1600cc on e85 be close to 1000cc on gas? i was reading something like that on honda-tech from a guy that does alot of tuning over there



R.I.P. Brian Klocke, you will never be forgotten

yep, that's about right.


-Trailblazer SS - not so custom 6.0L - custom intake - custom tune
- (1) 2.4L on an engine stand (1) blown trans (2) good quad trans (1) eco trans = party

1600cc? why dont u just hook up a rubber hose directly to the injector hole?



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- Sold my beloved J in April 2010 -

Viper98912 wrote:1600cc? why dont u just hook up a rubber hose directly to the injector hole?

because then it wouldn't be 1600cc.


-Trailblazer SS - not so custom 6.0L - custom intake - custom tune
- (1) 2.4L on an engine stand (1) blown trans (2) good quad trans (1) eco trans = party

SpyhunteR wrote:

Viper98912 wrote:1600cc? why dont u just hook up a rubber hose directly to the injector hole?

because then it wouldn't be 1600cc.[/quote


im not totally sure, ive known 2 ecos running DSM 1000cc's..idle iffy and cold days..but why would it be diff on and Ld??


Built&Boosted moar
04 Cavalier Turbo r.i.p my baby
2nd place 2009 GM tuner bash qwick 8--holla

SpyhunteR wrote:What's the largest fuel injector you LD9 guys have got to idle perfectly fine?

I'm talking about larger than 750cc injectors. I'm looking into some 1600cc squirters. I would like some people to chime in, on if you heard or know or have done tunes utilizing big arse puppies. I'm going E85, if anybody is wondering.

(side note: I'm back in the game)

You seem to have a disconnect from reality here.

How many people on this site do you happen to think are running 1200hp motors?

What do you mean by "idle perfectly fine"? -Idle "perfectly" like a 150hp engine? -or idle "perfectly" the same as a 1200hp engine?

Have you ever seen an example of a 1200hp 4-cyl idle perfectly fine?

Have you ever seen any 500hp 4cyl with 1200hp worth of injector idle "perfectly fine", no matter what control system is used?

Have you ever seen 400hp worth of injector per cylinder "idle perfectly" on any OEM control system?

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protomec wrote:

SpyhunteR wrote:What's the largest fuel injector you LD9 guys have got to idle perfectly fine?

I'm talking about larger than 750cc injectors. I'm looking into some 1600cc squirters. I would like some people to chime in, on if you heard or know or have done tunes utilizing big arse puppies. I'm going E85, if anybody is wondering.

(side note: I'm back in the game)

You seem to have a disconnect from reality here.

How many people on this site do you happen to think are running 1200hp motors?

What do you mean by "idle perfectly fine"? -Idle "perfectly" like a 150hp engine? -or idle "perfectly" the same as a 1200hp engine?

Have you ever seen an example of a 1200hp 4-cyl idle perfectly fine?

Have you ever seen any 500hp 4cyl with 1200hp worth of injector idle "perfectly fine", no matter what control system is used?

Have you ever seen 400hp worth of injector per cylinder "idle perfectly" on any OEM control system?

The amount of people on this site running 1200hp? That's irrelevant.

Up to 700hp is what I have seen so far.

I don't mind if you think I have a disconnect in reality.

I asked a question as I was curious as I have not attempted to see if HPT and the GM computer would really like it. The farthest I have gone is w/ 750cc.

I've had my car idle just stock-tastic w/ 750cc injectors.

I've seen cars idle reasonably well and quite liveable with injectors in the size I am talking about.

Your post didn't help very much at all, thanks much.


-Trailblazer SS - not so custom 6.0L - custom intake - custom tune
- (1) 2.4L on an engine stand (1) blown trans (2) good quad trans (1) eco trans = party

SpyhunteR wrote: The amount of people on this site running 1200hp? That's irrelevant.

I asked a question as I was curious as I have not attempted to see if HPT and the GM computer would really like it. The farthest I have gone is w/ 750cc.

I've had my car idle just stock-tastic w/ 750cc injectors.

I've seen cars idle reasonably well and quite liveable with injectors in the size I am talking about.

1200hp is irrevelent??? who else would have really truly needed and tried to run injectors that big?

And yet you asked a group of people who definitely haven't done it.

And how many of those cars that you have seen are running stock (even GM for that matter) electronics.

SpyhunteR wrote: Your post didn't help very much at all, thanks much.

You are correct entirely there. But its only because the only true purpose of your post is to "org masterbate" at the awe you are trying to inspire in others about yourself. Since I didn't inflate your ego, my reply was useless for you.

If the true purpose was really to get accurate info, none of the replies are "help very much at all" because none of them are by people with any real experience doing what you ask. Nor will any of them be.

Edited 1 time(s). Last edited Monday, February 25, 2008 5:51 PM

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btw it was a pita to tune Speedracers 750cc injectors at idle and he still had lean conditions up top.

I highly suggest standalone above the 1000cc mark.

Wrench Monkey wrote:btw it was a pita to tune Speedracers 750cc injectors at idle and he still had lean conditions up top.

I highly suggest standalone above the 1000cc mark.

That's weird. My car idled pretty much just dandy. However, up top it still could've used more ..........uh oomph.


-Trailblazer SS - not so custom 6.0L - custom intake - custom tune
- (1) 2.4L on an engine stand (1) blown trans (2) good quad trans (1) eco trans = party

protomec wrote:

SpyhunteR wrote: The amount of people on this site running 1200hp? That's irrelevant.

I asked a question as I was curious as I have not attempted to see if HPT and the GM computer would really like it. The farthest I have gone is w/ 750cc.

I've had my car idle just stock-tastic w/ 750cc injectors.

I've seen cars idle reasonably well and quite liveable with injectors in the size I am talking about.

1200hp is irrevelent??? who else would have really truly needed and tried to run injectors that big?

And yet you asked a group of people who definitely haven't done it.

And how many of those cars that you have seen are running stock (even GM for that matter) electronics.

SpyhunteR wrote: Your post didn't help very much at all, thanks much.

You are correct entirely there. But its only because the only true purpose of your post is to "org masterbate" at the awe you are trying to inspire in others about yourself. Since I didn't inflate your ego, my reply was useless for you.

If the true purpose was really to get accurate info, none of the replies are "help very much at all" because none of them are by people with any real experience doing what you ask. Nor will any of them be.

Lovely. i was actually looking for a legit answer, and if anybody in the woodwork woudl come out and chime in. If I want my ego stroked all I have to do is hang out with my lady.

yes, I need big ass injectors, period.


-Trailblazer SS - not so custom 6.0L - custom intake - custom tune
- (1) 2.4L on an engine stand (1) blown trans (2) good quad trans (1) eco trans = party

Hey man, i've tuned in 1000cc's on my car but I didn't do any fuel tuning other than idle. I would like to upgrade from my current 770's to 1000's sometime this summer so I used a buddies set just to see if I could achieve a decent idle. The idle was pretty smooth and throttle response seemed just as good as the 770's. Like I said I didn't do any fuel tuning for driveability so I can't say how difficult that might be.



President/Founder - 607 Motorsports

^Did you wire in some resistors so you could run low impedance injectors without burning up the drivers?^





"The FACTS are always subject to CHANGE once the TRUTH is applied"
"In the entire history of man the only stupid questions are the ones that don't get asked"

john317(AKA Gary the Old guy) wrote:^Did you wire in some resistors so you could run low impedance injectors without burning up the drivers?^

I know I will be.


-Trailblazer SS - not so custom 6.0L - custom intake - custom tune
- (1) 2.4L on an engine stand (1) blown trans (2) good quad trans (1) eco trans = party

As mentioned, I ran 1000cc injectors.

You fail to mention what psi of fuel pressure you plan to idle them at, though, as that affects things heavily.

I found a few issues with the 1000cc injectors, as expected. I didn't have much time to iron out the tuning but issues were:

-DFCO was dead lean. In the 20's, but idle was at 14.7:1 afr... basically I have to keep playing with the constant and after the fact sit down and adjust the idle table to achieve the right DCO and idle AFR.
-Cold startup was iffy... I drove the car into November and it ran rich at startup (but fine in September)... Again I'm not sure more tuning would have helped it but it may have. I do realize there is a modifier table for this but the injectors just reacted quite heavily to large temperature changes, and I'll assume that's all in the tuning. (Of which I had very very little)

There are a lot more factors to consider other than idle afr's etc. You can only put the injector constant so low before you're asking them to stay open for too little of a time, etc. I am nowhere near an expert on the subject, that's Todd's area to be honest.

That's my experience. I honestly don't know how you plan to idle 1600cc injectors as my constant was already quite small. like 0.028 or so. Judging by my DFCO it could stand to be a bit larger but with that said that's already kinda "down there".

Good luck.

-Chris-



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