SoloRacer

I just recieved my Guru Racing 52lb injectors but I have a question regarding the numbers wrote by hand in a silver pen on each injector. Example:

48.9
82
4-23-02

or

48.9
207
1-23-02


I assume the first number could be what the injectors flow benched at and the last number is the date but what would the middle number be? All the injectors have the same 48.9 number on them. If this is the injector size does that mean these are 49 lb injectors and not 52lb? Or is it that there is no such thing as a perfect 52lb injector and that they all test lower than the rating?

CPTdooberhead

I need new injectors of that size...what did u pay for yours?

Perry 951

Ditto

kelsean

I posted a similar question the other day. Sent my injectors off and these are the numbers i got back:

before test: 46, 42, 44, 45
after test: 46, 46, 46, 46

My question is the same -do i have 46# injectors, or is this just a number achieved via a non-standardized type of test (given the std injectors are 36#)?
<img src="confused.gif" border="0">

SoloRacer

I got my injectors and chips from Danno (Guru Racing) and paid $325US for the injectors. I took a look at my invoice and it says they are Delphi 55 lb/hour injectors. I know Delphi has a website. Maybe they can help me figure out if these are the right injectors or not.

Alan C.

The flow number you see has to do with the way it is tested. They usualy do the test at a set pressure and duty cycle which is not the max. I was told when I got my injectors from Marren that the sheets would not look like 83 lb injectors. They didn't and I'm not having any problems.

Alan

Danno

Those are the correct injectors, you just want to be concerned that they're matched for flow (should be less than 1%). I think they're tested up to 90% duty-cycle @ 3-bar which is the number you have.

The middle number could be a batch# or bin they came from. Make sure you install the ballast resistors so you don't fry your DME.

tecart

did you send a resistor kit to him with the 52 pounders? or is that part of the injector? ive heard about melting dme's with low impedence or ohm injectors that most bigger than stock varieties have, but what is this resisitor thingy?

Danno

Yup, all of our injectors come with a ballast-resistor assembly.

This is because the stock 951 injectors are a bizarre non-standard Bosch 5.5-ohm medium-impedance injector that is driven by the DME with a peak & hold signal. If one was to put in aftermarket low-impedance (2-3 ohm) peak & hold injectors, this would make the DME's driver-transistor pump out twice as much current due to the lower load. This is eventually cause the DME to fail; not immediately because it will appear to work fine, but the higher load WILL eventually fry the driver-transistor.

So some people just put in high-impedance saturated injectors. However, the DME is still sending out a peak & hold signal with a 25v blast in the beginning to rapidly open the injector then taper it off to around 6v to hold it open the remainder of the time. The problem with driving a high-impedance injector with this signal is that the initial blast is higher than the 12-volt square-wave signal those injectors were designed for, thus you can overheat them. Also the later 6v hold signal is lower than the signal that saturated injectors we designed for as well, and you would get lower and inconsistent fuel-delivery since the injector won't be fully open.

To solve this dilemma, we use a small ballast resistor that splits the difference betweent the stock 5.5-ohm Bosch and 2.5-ohm aftermarket injectors, thus allowing you to use the superior performance of the peak & hold injectors:



Also our injectors use an all-metal end for durability:



And the mechanism is the disc-type for super-accurate metering like the Lucas injectors. There are also 6 holes used to provide fine vaporization (especially in the larger sizes):

tecart

just wonder where do these resistors get placed? also how hard is it to do? do most of the people who have gone to 52 0r 55 or 72 pounders like rage, russ, john anderson, and others do this resistor kit install too or do they just do the bigger injectors, not that your kit dont fix all future meltdowns of the dme, but im curious to know if everone has done this or not? anyone who has got bigger injectors please respond if you did a kit like this to prevent overheating the dme for precautionary measures, thanks for the info

SoloRacer

Everything installed fairly easily. Danno has clear instructions on where to wire in the resistor pack. My friends and I were at first worried about the heat they might generate but after a few runs it was obvious that it was negligable.

Danno: The only concern we had was that the aftermarket injectors did not have a groove to put the retaining clip onto (the clip that holds the injector onto the fuel rail). Does this matter?

Danno

"the aftermarket injectors did not have a groove to put the retaining clip onto"

Really? They should have one:



Perhaps you may have inserted them a little too far into the fuel-rail and obscured the groove for the clip. I would tend to think this would only make a difference the next time you remove them. They all won't come off cleanly from the fuel-rail together. But then again it may not sealing as tight against the intake-manifold either if they are too far into the fuel rail <img src="graemlins/xyxwave.gif" border="0" alt="[bigbye]" />

Ahmet

Those are some nice injectors!
Ahmet

krickmann

Danno, I'm a little confused now. Are the Delphi 55 lb injectors you sell the disc-type like the Lucas, or the pintle-type tip, as you stated in your e-mail to me, "like the Bosch units which are much more resistant to clogging than the Lucas disc type of tips?"

IanM

I've got Bosch low-impedence 52# injectors, but no ballast resistor. It's worked fine so far, but I am interested in installing one of them ballast resistor doohickeys. How much you sell them thingys for Danno? I'd like to make an order!