100% IDC, bigger inj. or injection?

[blcknspo0ln]

I just did a log today with DSMLink and it looks like my IDC is always 90% on my Denso 660's. It's time to introduce more fuel into my system and I'm wondering which way should I go. I know meth will help lower IDC, but by how much? Do you guys think it'll be a better bet to just go with larger injectors?

 

[GVR4592]

I think it depends on your future plans for the car. There are a few things you could do to get more out of the 660's, or if you have plans to go bigger in the future just throw some 1000's in it.

If you want more out of the 660's, try to eliminate any restrictions in the feed line. The fuel filter, fuel filter outlet banjo fitting, and the rail inlet fitting, are all major restrictions.

Making sure the fuel pump has sufficient voltage is very important as well. If you don't have the pump rewired, make that a top priority. You can also raise the base fuel pressure to 50-55 psi and lower your global to get more headroom out of the 660's. Methanol is only going to help the situation, I think it's a good idea.

http://www.stevetek.com/R-FuelSys.html

 

[TSIMonsteR]

If I were in your shoes, you already have a nice turbo. Probably one you plan to keep until it dies. Go ahead and get meth injection. If it doesn't help enough, sell me the 660s for CHEAP and upgrade, !

 

[vaboys2ndgen]

Making sure the fuel pump has sufficient voltage is very important as well. If you don't have the pump rewired, make that a top priority. You can also raise the base fuel pressure to 50-55 psi and lower your global to get more headroom out of the 660's. Methanol is only going to help the situation, I think it's a good idea.

http://www.stevetek.com/R-FuelSys.html

PTE 5031BB turbo l DSMLink l Denso 660 l Aeromotive AFPR / SS lines l 1G TB l JMF SMIM l Walbro 255 non-rewired l 2.5" Magnaflow turboback l FP recirc. intake pipe w/ 4.5" air filter l MBC l SSAC Big 2G FMIC kit l Greddy Type S BOV l Plenty more...

it definately makes a big difference having the fuel pump rewired.

 

[CanadianTSi]

I'd sell the 660's and get some 850-1000's.

 

[2gGSX]

The fuel line issue, especially the filter, filter outlet, and rail inlet are all going to be restrictions even if you do upgrade to 1000cc injectors. You should consider removing the choke point first instead of trying to shove more fuel through.

 

[vaboys2ndgen]

not to take over the thread, but for others how would u eliminate the restriction? larger -an line.

 

[GVR4592]

Read the link I posted.

 

[blcknspo0ln]

Thanks for all of the suggestions, I'll be ordering my snow performance meth kit very shortly (along with finally getting around to rewiring my 255).

 

[TSIMonsteR]

I say Devil's Own Water injection FTW. Anyway, good luck. You may want to go ahead to upgrade at least the lines from the rail to the filter while your at it.

 

[DSMunknown]

I'd sell the 660's and get some 850-1000's.

Times two-and-a-half. You'll just be happier (and your mind will be more at ease) if you upgrade to at least 850s (especially when you have the luxury of DSM Link).

 

[CanadianTSi]

The only real bad restriction in the Stock Lines is the Filter to Rail line. The rest of the system is good for 130mph+.

I would Imagine with your mods your flowing right around 45lbs/min which is right where the Injectors start to max out. So if you plan to go any further at all your going to need bigger injectors.

 

[blcknspo0ln]

You're right tyler. If funds allow, I will be doing all 3 things at one time (inj, injection, rewire). I also already have SS lines from the filter to the rail, so if you're right, I won't be needing any modification to that part of the system.

As for 45 lb/min you hit it on the head. I'm flowing 46 lb/min @ 23.5psi (dropping to 20, damn internal gate; gotta tighten it).

 

[olmytsi]

I'm in the same boat. Im running a 6 bolt, dsmlink, turbonetics 50 trim, 660s, non rewired 255 high pressure and hks 272s and i'm at 87% duty cycle at 22 psi. I will need injectors very soon cause i am in the process of switching to an external setup to run more boost. My current agp actuator is dying ;22psi is the max i can get and it's not enough

What brand 1000 do you guys recommend as far as reliability & quality? I also want to try running some e85 mixed with 93 so i really want those bigger injectors.

 

[blcknspo0ln]

I chose FIC 950's from extremepsi.com; they are on their way as we speak Next up will be devilsown meth kit, or snow performance !

 

[TSIMonsteR]

Nice, keep us updated on the power numbers once you get it re-tuned for that meth.

Good choice if you ask me!

 

[kahl23]

The biggest restriction in the system is actually in the return line. The higher flowing system is trying to shove too much fuel back through the return line, so the pressure you set at the regulator is actually lower than it is at the injectors. Until you fix this, something like raising the fuel pressure at the regulator won't do much. The good news is you can just run some some ss line or large diameter hard brake line to fix the problem.

For the front end of the system: http://www.dsmtuners.com/forums/showthread.php?t=209428

 

[DSMunknown]

I chose FIC 950's from extremepsi.com; they are on their way as we speak

Before the install, I would highly recommend sending all four injectors to a place like FIC and have them flow tested. This way, you know where to stick them on the fuel rail.

 

[DSMunknown]

The biggest restriction in the system is actually in the return line. The higher flowing system is trying to shove too much fuel back through the return line, so the pressure you set at the regulator is actually lower than it is at the injectors. Until you fix this, something like raising the fuel pressure at the regulator won't do much. The good news is you can just run some some ss line or large diameter hard brake line to fix the problem.

I was thinking about that, but on the other hand, who cares if a lot of fuel is just sitting in the fuel rail? Generally at WOT, most of the fuel is getting used up that goes into the fuel rail. And it's not like the fuel pump is pumping at the same PSI the entire time its being driven around town. I undertand that the fuel needs to return back to the fuel tank, but I wonder how "necessary" it is to upgrade the fuel return line for most "normal" applications.

 

[blcknspo0ln]

For anyone who cares, I got my FIC 950's today and they're already in.

SS line from fuel filter > rail and rail > AFPR
stock return line from AFPR
Walbro 255 HP @ 44 psi
BB5031 turbo @ 24.4 psi (via GM 3.3bar) @ 45.5 lb/min
FIC 950cc injectors from extremepsi.com

I just did a log and my IDC's went from a soaring 100% to 68% WOT, ceteris paribus.

Knock is pretty much non-existant with AFR's skimming 11:1

 

[blcknspo0ln]

Before the install, I would highly recommend sending all four injectors to a place like FIC and have them flow tested. This way, you know where to stick them on the fuel rail.

On a side note, these are FIC injectors, one would only assume that FIC flow-tested for quality control on their own stuff, no?

I hate to ASSume, but I think these were already Q/C checked because it has 950cc hand engraved on each injector.

 

[DSMunknown]

On a side note, these are FIC injectors, one would only assume that FIC flow-tested for quality control on their own stuff, no?

I hate to ASSume, but I think these were already Q/C checked because it has 950cc hand engraved on each injector.

Just because the injectors are "engraved" doesn't mean squat. I asked a similar question here and Dark_Horse did a nice job answering my question in a different thread here. Of course, in the next reply in the second link I just provided, Mister Jewer refutes the point and would seem to agree with you when regarding FIC injectors. He does make some qualifications, though.

 

[blcknspo0ln]

hah, I hear ya. I couldn't really care less if the injectors I bought flowed 920cc or 1000cc's. I guess my point is that I have DSMLink to tune in whatever flow rate it is, via LTFTs.

 

[nightspeed87]

For anyone who cares, I got my FIC 950's today and they're already in.

SS line from fuel filter > rail and rail > AFPR
stock return line from AFPR
Walbro 255 HP @ 44 psi
BB5031 turbo @ 24.4 psi (via GM 3.3bar) @ 45.5 lb/min
FIC 950cc injectors from extremepsi.com

I just did a log and my IDC's went from a soaring 100% to 68% WOT, ceteris paribus.

Knock is pretty much non-existant with AFR's skimming 11:1

Glad to hear it. Maybe this will teach people to go big the first time so they dont have to spend twice... Even when I was still on a 14b I went straight to 850s for injector upgrade.
( I have dsm chip to control it which I highly recommend over safc if not enough money is available for link. )

hah, I hear ya. I couldn't really care less if the injectors I bought flowed 920cc or 1000cc's. I guess my point is that I have DSMLink to tune in whatever flow rate it is, via LTFTs.

A little thing maybe that will give you an idea,

My dsm is running 850s cc FICs.. I am running the n/t 4g63 fpr which gives you a base psi of like 47.6...( and still rises on a 1:1 ratio) Therefore by just compensating in the actual flow rate between injectors and fuel pressure, I actually came out with like 900cc's worth of fuel flow that we told it to run ( By calculating this correctly you wont run rich or lean by running the added pressure)

This works on those with stock injectors as well... For instance the 47.6 psi n/t fpr base w/ 450s will actually give you something like 505.cc's, so then youd just tell your ecu that you have 505 cc injectors basically...

Make sense? ( You have to actually calculate this in though if you were to do this correctly.)

Therefore if you dont have a afpr, you could just pick up a n/t fpr from the junkyard or some sort for cheap and try this out for even extra fuel flow, and somewhere I heard raising the base fp helps deal with fuel pressure over run ( from upgraded fuel pumps.)
Hence why 2gs dont have fuel pressure over run as bad a 1gs.... ( 43 psi vs the 1gs 37ish psi )

 

[blcknspo0ln]

I understand your theory, but I dislike the idea of raising base fuel pressure to correct for a lack of fuel problem. Keeping the afpr at 43.5 and getting bigger injectors is a much better solution for me.