Porsche-O-Phile

Hypothetically speaking, of course. . .

If someone were to upgrade to a t04b/0.50 and was planning on running 18-20 psi boost, what would be the "best" injector setup? Delphis are available in the following pph ratings:
50, 55, 65, 75, 85, and 95

And Siemens are for:
48, 55, 72, 83, and 93

Would it be fair to say one should simply get the largest injector possible to avoid pushing the duty cycle too hard? A lot of guys seem to run 55s (either flavor, Siemens or Delphi) without many complaints but what's the advantage of that versus a larger one, particularly if costs are very close or identical?

Thanks, also anyone got good pics of ballast resistor installs?

Charlie944

Hey buddy, use the calculations found HERE
This should help you decide what sizes to go with. Personally, I went bigger (75# Delphi's) than currently needed to play it safe and allow for further mods later. Sorry, no ballast resistors here, running a TEC2.
How is your Callaway coming along? I am getting ready to do a KEP/930 disc/LWFW upgrade in mine. Clutch slips under abrupt power right now.

Mike Murcia

Unless you spend a lot of money on standalone or the new Vitesse software/hardware, 55# is about as large as you can go with the stock DME without noticing differences in how your car idles. I've never personally tried larger injectors, it just what has been posted. It has something to do with the low duty cycle at idle. This is why a lot of guys have chosen injectors in the 55# range.

evil 944t

If you have VR setup or stand alone. 55's are fine. If your going to push it hard or upgrade later, 72's and a larger fuel pump would be ideal.

gregeast

I just installed new 55# injectors from Vitesse this week. I was dreading the ballast resistor installation, I'm never comfortable cutting into the wiring harness. Turns out it was really no big deal.

Here's what I did:

1. Bought a piece of ~1/4" thick aluminum at Home Depot to use as a heat sink. Cut to a little larger than the size of the resistors.

2. Bought some thermal glue from a local PC shop, the same stuff that's used to glue heat sinks onto CPU's. Glued the resistors to the aluminum.

3. The fuel injector wires are #14 & #15 on the DME. The connector on the harness that goes into the DME comes apart by removing the screw on the end and then sliding it off. On my car the two wires were grey and grey with a black stripe but it's easy to remove the connector so make sure that you have whatever wires are in #14 &#15

4. The resistors I got had terminals on either end that fit perfectly onto crimp on electrical connectors. Take a deep breath, cut the two wires ~10" from the DME, strip back a 1/4" or so, crimp on the connectors to the exposed wire and then attach them to the resistors et voila, fuel o' plenty!

Greg

RolexNJ

Do not, I repeat do not use that calculator. I called that company several times, because I thought it was off based upon the variables I put in. What they recomment as a B.S.F.C on their web site is off! Don't use it. And by the way, this is the same one Danno recommends people to use too, go figure

Porsche-O-Phile: I would agree 100% to what Evil said. One thing you need to consider is future growth too. That should be taken into consideration. For me, I could have went with 72 lbs, and it would have been "ok" for the BHP I'm looking to make. But as per the recommendation of Vitesse, I went with the 83 lb. ones to have extra room, with the understanding that my BHP needs will grow. And with his custom chips, they can accomodate the 83 lb. ones too, kool! Quite honestly, I would "strongly" recommend that you PM John and ask him what he thinks. In the area of EMS stuff, John is the man.

Just my two cents.



EDIT: Mike Murcia - "Unless you spend a lot of money on standalone or the new Vitesse software/hardware, 55# is about as large as you can go with the stock DME without noticing differences in how your car idles." - So not true my friend. I have 83 lb. on my car, and it idles like a ***** cat, thanks to John and his EMS stuff. And this is fact, no fiction. You can ask Special Tool, he tuned the car!

evil 944t

I went with 83's on my 2.5 as I also know many people running 83's on thier track cars (stand alones with high RPM's). I would go bigger than 83's with more CC's. Just my opinion and no I don't want to share why

RolexNJ

You're an ***!

evil 944t

Hey, thats MR. *** to you!

Porsche-O-Phile

Yea, I'm eventually thinking Vitesse chips and MAF but the pricing is just silly high for me (especially right now) - makes it at least a year down the road. So, turbo & basic chips first, then exhaust upgrades, then suspension, then MAF. Unless I find a good deal.

evil 944t

Why don't you skip the turbo and get the MAF, chip, injector set up first. You will get some nice gains with the stock turbo. Then you can get any turbo after that.

Just my 2c

Actually, I just reread you post.. Get an exhaust first then MAF etc.. At least it will sound fast..lol It won't be as pricey as the MAF set up and its a good building block.

ibkevin

Stick with bosch or Siemens, and Evil was pretty dead-on. Most people running 72s are in the 250hp and up with larger fuel pumps and trick clutches.

SamGrant951

Arent you guys saying the same thing? Why are you disagreeing NJ? He said 55# is about as large as one would want to go on stock DME UNLESS you use Vitesse software/hardware or standalone which everyone knows you are...

evil 944t

You mean 350rwhp+, right?

Alpine951

I'll have some 65# Delphis for sale as soon as I pull them that I bought last February and used for 5 months. PM if interested.