20G Best Choice for me (20-22 psi on 91 octane)

[DSM_ThuNDeR]

I was re-searching and re-searching but found VERY DIFFERENT ANSWERS everywhere. I had the idea in mind to run DSMLINK, but since I'm not exactly a person who likes to mess with "TUNING" devices, I have decided to go along with a KEYdriver Chip for my 2G. With that In mind, I went to roadrace's injector chart, then I simply looked around in this site and many other dsm forums to find my answer, but no luck. I'm wondering if 680cc injectors would be the best choice to run 20-22 psi on 91 OCTANE with a td05h 20G turbo? I don't want to come up short on fuel, neither be too rich. Basically there will be my mods when I have received my Eprom ECU socketed:

20G clipped, internally gated
255 hp lph Walbro
aeromotive FPR
ported 2g exhaust mani
02 atmospheric dump
joe P. manual boost controller
3" downpipe and CATback
Front Mount intercooler 28x3x12
2.5 aluminum hard piping
1G bov
MAYBE AFC for a fine tune and wideband 02.
INJECTORS(GUIDE ME GUYS)

thanks in advanced.

 

[2gGSX]

If you're getting a chip to compensate for injectors then I would say go bigger. There's very little reason not to, and it will give you more headroom.

If you are getting a deal on 680's however, they will work fine for your setup. With a 2g on pump gas and a 10.5:1 AFR, you should be able to support roughly 40 lbs/min at 85% IDC. When only running ~20 psi on that turbo you should be well within this limit. If you decide to up the boost though, you will start to push the IDCs and get into a pretty dangerous area. With that said, I would recommend bigger injectors, although the 680's will do.

 

[toofast82]

I would go bigger(850-1000cc) since it will be properly compensated for. 650cc will be fine for the 20-22psi, if you go higher, i would believe youd be pretty close to maxing them.
The keydiver may need some "fine" tuning as well with an afc,etc
On my last dsm, i had 1000cc with a keydiver and afc and it worked great. Good gas mileage as well and low idc's

 

[pboglio]

Agreed. I've run my 660cc injectors at 95% duty cycle on 28 psi & 44 lb/min. I'd go a good bit bigger. That 20g could pin those 650cc injectors wide open at higher boost levels. Give yourself some headroom.

 

[DSM_ThuNDeR]

hmmmm. Ok I see what you mean. I'm actually NOW thinking of Denso's 720cc's or some FIC 750cc's. thanks for the advice.

 

[Strm Trpr]

For comparison I've got the GReddy TD05H 18g with the TO4E 3" inlet comp cover capable of pushing 40lbs/min.
I've got it tuned to 10.8:1 and 22-20 psi on 91 craptane with ZERO knock and ZERO boost leaks.
Airflow is really close from 5k-5.5k.
I'm only pushing 34lbs/min and my IDC's are at 75% with Denso 720's.
The rest of my mods are in my profile.
DSMLink is the tuning tool of choice.
I suggest going to their site downloading their manual and software.
Then spend sometime cruising the forums for .dat files and learn what's what.
This is the honest to god truth, boost leaks make it almost impossible to get above 18psi on 91 octane.
I rebuilt my 2g TB and was able to get the tune that you see there.

Here's the link to the software download.
ECMTuning, Inc.
Click on V2 DSMLink (v2.5.2.27) and download it.
Don't forget to get the user manual at the very bottom of that page.
Here's another link to the ECMTuning - wiki.
Plenty of good stuff there too.

Here are a couple of datalogs to get you started.

But if you're deadset on a Keydiver chip.... then goodluck.

I have set of Denso 720's that I don't need.

 

[pboglio]

Alot depends on the fuel pump as well. I would hate to be pulling a top speed run and have an injector lock up. Thats why the 85% duty cycle rule is a good one to keep.

I've heard a rumor that the Denso Injectors are actually underrated, which is a good thing.

 

[2gGSX]

Alot depends on the fuel pump as well. I would hate to be pulling a top speed run and have an injector lock up. Thats why the 85% duty cycle rule is a good one to keep.

I've heard a rumor that the Denso Injectors are actually underrated, which is a good thing.

Having an injector suddenly lock up during a pull, regardless of duty cycle, is going to be catastrophic

While the Densos generally flow more than they're rated, the problem is that there seems to be a lot of variation between individual injectors, even within a set.

 

[pboglio]

That may be true, but you run a solenoid at 100% duty cycle long enough and it IS likely to overheat and fail. I'll take the Denso injectors over any of the other crap thats out there.

 

[Joesmoke]

Similar to my setup:
20g
680's
keydiver chip
yada yada

Works well. Dont kill yourself with over analyzing

With the keydiver chip, he can set it up a little leaner (but safe) from stock. You wont use as much injector that way.

With a keydiver chip, you dont need any other piggybacks (AFC etc). Where an AFC is nice is even with a keydiver chip, once you run water injection, you still need to adjust the fuel.

Have fun and remember, dont over analyze.

 

[mikelv]

DSMLink is the tuning tool of choice.
Plenty of good stuff there too.

But if you're deadset on a Keydiver chip.... then goodluck.

+1
Go Link, or go home.

You'll never need another EMS again.

Hey I need some 720's let me know what you want for them.

 

[toofast82]

+1
Go Link, or go home.

You'll never need another EMS again.

Hey I need some 720's let me know what you want for them.

Ill admit, there are many cheaper options for 1g guys. But 2g with tunerpro has full timing/fuel control, idle compensation, fuel cut removal, etc and is $free$ software. He has a 95 so should have eprom. Socketing is $50 while a Moates1 burner and chips is under $100. Hell need a logging device as well.

 

[spyderturbo007]

This post of mine might help.

It will provide you with theoretical flow numbers for most injectors and fuel pumps at different boost pressures and IDC's. Take a look at the flow numbers for the 20g at the boost pressure you are looking for and find a good match.