660's or 780's?????? HELP ASAP!!!

[yotabeater]

i've reached my limits with my 550's, and am in the market for new injectors. i am looking at a set of 660's and a set of 780's. not sure if i'll have to change my whole setup if i go with the 780's, but i don't want to buy another set of injectors in 6 months.

right now i have a 91 tsi, b16g, fmic, 3" maf w/ translator (blow-through, venting), 255 pump, afpr, afc, logger, etc.

also, what's the difference between the pte injectors and denso's? the 780's are pte's, and the 660's are denso's, and i can get a good deal on both.

i heard if i go with the 780's i might not be able to lean it out enough on the afc, or i might have a hard time tuning them. it's my daily driver by the way. any input is appreciated. thanks for the space. -Josh

 

[Sk8er07999]

I have a similar set up as you but with 14b and 780's. I don't recomend this. I am running negative correction on the maft and on the safc. With so much negative correction I get a ton of timing advance. This gives me a ton of knock. :thumbdown So I am saving for an eprom and a chip. This will correct the timing problem and get rid of the knock. So if you don't want to change your setup alot don't get them.

 

[dsm10sec]

Why the hell are you runnin 780s on a 14b? I have a 20g and am running 750s... Anyways, don't get 780s for just a 16g, too many people over kill on injectors and end up like the guy above here with too much advance and get alot of knock.

 

[Sk8er07999]

Why the hell are you runnin 780s on a 14b? I have a 20g and am running 750s... Anyways, don't get 780s for just a 16g, too many people over kill on injectors and end up like the guy above here with too much advance and get alot of knock.

I had the plan to get a larger turbo and didn't wanna end up like the guy above me buying injectors a few times. And yes I wouldn't recomend it unless your going to run link or ems or get chipped with tmo or similar. or else you won't be able to control the knock situation.

 

[RoasT BeeF]

Why the hell are you runnin 780s on a 14b? I have a 20g and am running 750s... Anyways, don't get 780s for just a 16g, too many people over kill on injectors and end up like the guy above here with too much advance and get alot of knock.

Probably why he DIDNT recommend them. People learn from their mistakes ya know. Looks to me like hes trying to help the guy not make the same mistake he did...

 

[gringoloco]

i've reached my limits with my 550's, and am in the market for new injectors

How do you know that you have maxed them out is my question? Did you log the duty cycle of your injectors? Also something is wrong there, you shouldnt of been able to max them out unless you are running alot more boost then I think. Im currently running 550's @ 25psi on a 50 trim on 93 pump and I havent maxed them out yet, they are in the 80-85% duty cycle range. So I ordered a set of 680's that are going in now. Also if you go with anything larger than a set of 680's you will need a chip, dsmlink, etc to run them properly the S-AFC will not be able to lean them out enough. But how the heck did you max the 550's out, I just find that hard to believe on a 16g. 550 cc injectors are plenty for a 16g, the only way I can see you maxing out the 550's is you didnt actually get 550's you recieved a set of 510's or lower. When I ran 20-24 psi on my 16g setup I never saw more than 73% duty cycle on my logs. But 650's or larger are just over kill for a 16g setup and you will be running pig rich and get the advanced timing, knock and just make the car run like crap. I would take those injectors out if they are truely maxed from data logs, and get them flow tested to make sure they are 550's.

 

[NOSLO2PT0]

Im currently running 550's @ 25psi on a 50 trim on 93 pump and I havent maxed them out yet,

That's pretty damn good. Almost too good. I was running 25psi on 93 octane, with 660's, a Supra TT pump, with 45psi base fuel pressure. My Injector Duty cycle's were in the mid 90's. Curious how you were able to add enough fuel to keep detonation at bay w/25psi on 93 octane. Unless your base fuel pressure was 60psi or more.

 

[Car Cannibal]

I would get the 680's and then run alky. With both of those, you can run some major HP without upgrading to 780's. Julio at www.alkycontrol.com runs 20-25% of his fuel as alky injection. 550 to 680's are a 24% increase. Pretty much, he made up for running larger injectors by just upping the alky and running a ton more boost.

I ditched the Safc for the Keydiver Chip, no timing worries here. And with the Maft, its easy as hell to dial this car in. Alky tuning starts next weekend. .

 

[gringoloco]

That's pretty damn good. Almost too good. I was running 25psi on 93 octane, with 660's, a Supra TT pump, with 45psi base fuel pressure. My Injector Duty cycle's were in the mid 90's. Curious how you were able to add enough fuel to keep detonation at bay w/25psi on 93 octane. Unless your base fuel pressure was 60psi or more.

BFP is set at 50 psi I believe, ill have to double check. But I know of another person that ran higher boost on a set of 550's on a 57 trim on race gas though and still never maxed them out. Its all a matter of tuning, and parts. I noticed your running a supra pump not sure how much differant that is then my walbro. There are alot of factors involved, etc. but im just stating what the log was reading. But on that note I restate what I had said that log was at 23psi on 93 octane. When I upped it to 25psi I was in the low 90% on my 550's.

 

[yotabeater]

thanks to all that have replied.

my logger set-up can't monitor injector duty cycle (mmcd software), only pulse. when i had it @ WOT the pulse read 17.45ms. i have been having problems with knock and timing advance, and went to pina motorsports in kent. nick told me my injectors are probably maxed out, and to step up to 680's. he didn't recommend going with 780's, but i figured between the MAF translator, afc, and adjustable fpr, i'd be able to tune it pretty well. maybe i was wrong?

i just opened up the translator box, and the settings were as follows:
base--idle--mid--WOT
+4 0 0 0

so i screwed with them a bit, raised idle mid and WOT to +2, and leaned out the afc from -4 to -10 and the knock went away.

what other kinds of mods will i have to make to run the 780's, or even 660's for that matter? thanks. -Josh

 

[ShapeGSX]

How do you know that you have maxed them out is my question? Did you log the duty cycle of your injectors? Also something is wrong there, you shouldnt of been able to max them out unless you are running alot more boost then I think. Im currently running 550's @ 25psi on a 50 trim on 93 pump and I havent maxed them out yet, they are in the 80-85% duty cycle range. So I ordered a set of 680's that are going in now. Also if you go with anything larger than a set of 680's you will need a chip, dsmlink, etc to run them properly the S-AFC will not be able to lean them out enough. But how the heck did you max the 550's out, I just find that hard to believe on a 16g. 550 cc injectors are plenty for a 16g, the only way I can see you maxing out the 550's is you didnt actually get 550's you recieved a set of 510's or lower. When I ran 20-24 psi on my 16g setup I never saw more than 73% duty cycle on my logs. But 650's or larger are just over kill for a 16g setup and you will be running pig rich and get the advanced timing, knock and just make the car run like crap. I would take those injectors out if they are truely maxed from data logs, and get them flow tested to make sure they are 550's.

What is your A:F ratio?

I know that at 24psi on an Evo III 16G, I was well over 100% IDC at a 12:1 A:F ratio (measured with a wideband).

You must be running a lot leaner than 12:1. I don't think I'd want to run that lean.

 

[2-0turbo]

Remember too, that 85% should be your upper limit for IDC if you care about reliability. Those of you saying you are running 100% IDC are no longer controlling how much fuel you are injecting--the injector is open all the time. This is not only bad for control of AFR, but for injector life as well. And if you are running 100% IDC, you might need more and run the risk of going lean at the worst possible time.

 

[dsm10sec]

I'm at 93% DC with my 750s... Think I should change em or is it fine there?

 

[gringoloco]

I'm at 93% DC with my 750s... Think I should change em or is it fine there?

93% DC with 750's, what turbo are you running? You can run that, but that amount of cycle is harsh on the injectors. Ive always been told anything over 80% should be upgraded to the next level set. But with 750s what do you have managing them?

 

[ryanman]

my logger set-up can't monitor injector duty cycle (mmcd software), only pulse.

I use MMcd and I can monitor duty cycle on mine. Have you DL'd the newest version of mmcd?

http://mmcdlogger.sourceforge.net/

 

[dsm10sec]

Gringo, I have a 20g, I run a MAF-T with an SAFC. AND NO I'm not running pig rich, it's tuned perfectly (says the seat of my pants, EGT, o2,and fuel trim) Haven't gotten it to the dyno yet, but I will dyno it right after Christmas.

 

[yotabeater]

just downloaded the newest version of mmcd, and the duty cycle actually read 100.7% at one point. so can anyone tell me if i'll be okay running 780's with my current set-up? or if i should just get 660's? thanks.

 

[dsm10sec]

Well, I'm on 750s on a bigger turbo.. Think about it.

 

[ShapeGSX]

Well, I'm on 750s on a bigger turbo.. Think about it.

Do you know for certain that you aren't running the 750s wide open?

People have relied on race gas to save their engines with wildly lean A:F ratios for a long time. Particularly with systems like the VPC. I suspect that there is more power to be made with a proper A:F ratio with larger injectors. And the power should be made much more safely, as well.

 

[yotabeater]

Well, I'm on 750s on a bigger turbo.. Think about it.

what do you mean by this? just tell me which size you think will work best with my current set-up. i already told you the 550's are @ 100% duty cycle during WOT pulls.

 

[NOSLO2PT0]

You will be just fine with 660's

 

[dsm10sec]

Do you know for certain that you aren't running the 750s wide open?

People have relied on race gas to save their engines with wildly lean A:F ratios for a long time. Particularly with systems like the VPC. I suspect that there is more power to be made with a proper A:F ratio with larger injectors. And the power should be made much more safely, as well.

My datalogger is what's telling me they're at 93%. I am dynoing right after newyears, so we'll see if I can get more power out of it. If I can get some things sold that are laying around I'll get some 800s or something.

 

[ShapeGSX]

My datalogger is what's telling me they're at 93%. I am dynoing right after newyears, so we'll see if I can get more power out of it. If I can get some things sold that are laying around I'll get some 800s or something.

I'm not saying that 750s aren't right for your car. I just know nothing about your car so I have no frame of reference. What is your best trap speed? Have any dyno plots? What A:F ratio do you run? What turbo do you run?

 

[dsm10sec]

Haven't gotten to dyno or track yet, only have 153 miles on it since it was rebuilt. I blew the head up and it sat in the garage for 6 months.

 

[yotabeater]

so can anyone besides noslo2pto give me their input on whether i should get 660's or 780's? is it absolutely necessary to get an eprom ecu w/ chips, dsmlink, etc if i go with 780's? or can i run them right now, no problem? i want to be able to run 20-22 pounds of boost no problem, just don't have enough injector right now. thanks. -Josh