Injector Rail

[Chris26]

The rail seems hard to pull from the injectors...all fasteners are removed... and bolts..

[Chris26]

I'm getting 12.8ohms across the board for the injectors:dancing

[A26B]

They are hard to remove. Dry, 25 yr old o-rings are the problem.
I pry the rail up with the wooden handle of a small ball peen hammer.

Replace with all new o-rings, lightly lubed with motor oil, attach injectors to the rails & press down evenly until the rail brackets are down & bolt in place.

[Chris26]

Thanks!!!. I found water in the rails and debris in the injectors. F%@k!!!!

[XfireZ51]

Thanks!!!. I found water in the rails and debris in the injectors. F%@k!!!!

That'll do it.

[Chris26]

Yes it will!!! white smoke and all!!!

[Hib Halverson]

If you have liquid water in the fuel rail and this was the engine out of a '90 which had been sitting for two years and which was discussed in another thread, you may have corrosion problems throughout the fuel system.

That might neither be fun nor cheap to repair.

You better get the pumps out of the tank for inspection then clean out the tank. Also, you may need to replace the hard lines running from the tank, foward along the left frame rail.

Get the fuel rail off and apart to see what level of corrosion might be inside.

Might as well scrap all 16 injectors as if they are original, and you found water in the fuel rail, they'll be full of rust.

Best LT5 injectors come from RCEngineering. There are other vendors which sell injectors almost as good. There are many vendors which sell injectors which are s**t.

[Chris26]

Hi, Thanks for the reply!!!. The corrosion in the rails is next to none...when I pulled the rails a little bit of water got absorbed into my towel.Then the rest smelled (and tasted) like raw fuel. The tank was removed and cleaned the year prior. The secondary injectors look like S#$T!!!!! I filled the tank full of premium and put a fuel treatment in for any remaining condensation... I plan on running the pump via the red jumper to clear the lines before firing the beast up after I go through the engine.

[Dynomite]

If you have liquid water in the fuel rail and this was the engine out of a '90 which had been sitting for two years and which was discussed in another thread, you may have corrosion problems throughout the fuel system.

That might neither be fun nor cheap to repair.

You better get the pumps out of the tank for inspection then clean out the tank. Also, you may need to replace the hard lines running from the tank, foward along the left frame rail.

Get the fuel rail off and apart to see what level of corrosion might be inside.

Might as well scrap all 16 injectors as if they are original, and you found water in the fuel rail, they'll be full of rust.

Best LT5 injectors come from RCEngineering. There are other vendors which sell injectors almost as good. There are many vendors which sell injectors which are s**t.

I use RC SL4-205s

http://i287.photobucket.com/albums/ll142/dynomite007/LT5/RCInjectors.jpg

[GOLDCYLON]

I use RC SL4-205s

http://i287.photobucket.com/albums/ll142/dynomite007/LT5/RCInjectors.jpg

Same as me. :cheers:

[Chris26]

Any other options on "good" injectors???

[Demps]

I have had very good results with Accel 21lb injectors

Ted

[Paul Workman]

Excellent results w/ Accel (150821 from Summit). Purchase new Viton (sp?) O-rings from Jerry's Gaskets.

FIC, a supporting vendor: Ask Jon for new stainless injectors kit (includes gaskets and O-rings from Jerry's too. I've no personal experience w/ these, but those that do, seem to like them fine.)

[XfireZ51]

The RCs are rated 20lbs @43.5 psi, which is 10% less than what the stock calibration is using (22.7lbs) for calculating pulse width. Additionally, the electrical characteristics of the RCs very likely different from the Bosch. I believe RC can provide the Injector Offset v Batt Voltage values for their injectors.
Technically speaking, you would want to make those changes to the calibration
and see how close the stock VE tables are at that point. It will also have an effect on WOT tune.
And yes I know that people have been using RC injectors or other non-stock injectors without having made those changes.

[Hib Halverson]

RCEngineering injectors for LT5s are available in a couple of different flow ratings.

I see some people here are using the SL4-205s.

I used the SL4-210s in the 500-hp, Automasters Street Skinner engine I had in Barney. At 43.5-psi they flowed 200-202 CCs per minute.

[Chris26]

How about bosch???

[Racinfan83]

Marc Haibeck put Accel injectors in mine. That is pretty much all the endorsement I would need to use those again..:cheers:

[tpepmeie]

The RCs are rated 20lbs @43.5 psi, which is 10% less than what the stock calibration is using (22.7lbs) for calculating pulse width.

Don't forget the rail pressure is regulated to 350 kpa (50.8psi) not the standard 43.5psi rating pressure. That brings the injector flow capability closer to the calibration value.

[Chris26]

accel vs RC????

[XfireZ51]

Don't forget the rail pressure is regulated to 350 kpa (50.8psi) not the standard 43.5psi rating pressure. That brings the injector flow capability closer to the calibration value.

Todd,

For purposes of comparison, aren't the Bosch injectors rated at 43.5?
Using a 50.8psi fuel pressure brings flow for the RCs to 21.5.
Not sure that the calibration value is at a 50.8psi. You might be able to shed more light on that.

Chris,

I've had the same Accels in my motor since 2007 and they continue to operate without any hiccup. Although the Accels are rated at 21lbs @43.5psi, I had one tested and it flowed 20lbs @43.5.
This has its greatest effect on idle and low pulsewidth situations.The voltage bias (which is not available from Accel) is also different from the stock Bosch. The injector also tested linear down to 1.5ms.

[tpepmeie]

Todd,
For purposes of comparison, aren't the Bosch injectors rated at 43.5?

It depends on who's quoting them. Most aftermarket resellers will use 43.5, because it is more standard. However, if you use Bosch-made Ford Motorsports injectors, they are typically rated at 39.15 psi. For example, the red Bosch 30-lbers I had in the 427 were Ford Motorsports injectors rated at 30lbs @ 39.15 psi. Ford provides calibration data which had the characterizations at all different pressures (they flow ~35 lbs/hr at our rail pressure.) The conversion from Ford characterization to GM tables is quite involved, but can be done.


Using a 50.8psi fuel pressure brings flow for the RCs to 21.5.
Not sure that the calibration value is at a 50.8psi. You might be able to shed more light on that.


I wouldn't speculate on what or why the GM calibration uses that 22.7 flow rate--I've always wondered that myself. I'm sure there is a reason. However, to accurately meter the fuel delivery, that variable needs to reflect the operating conditions of the injector. There is no other calculation in the program which converts that data value to the actual rail pressure. The regulator is designed to deliver a constant 3.5 bar (50.8 psi) pressure difference between the manifold and the injector feed. It's the flow rate under those conditions which dictate how much mass of fuel is delivered for a given pulse width.

Years ago, I had some lightly used stock injectors tested. They flowed 20.1 lbs/hr @ 43.5psi, which is 21.7 lbs/hr @ 50.8psi. Still short of the factory calibration value (22.78). It is possible that the flow v. pressure is not perfectly linear for the multecs, but who knows.

[XfireZ51]

Todd,

Thanks great info. Yeah, 43.5 seems to be the standard most vendors use, although the Accels were usually shown at 19# @ 39psi. They were mostly used for Mustangs I believe.

[tpepmeie]

One last point. If anybody uses the ford motorsports injectors and wants the injector characterization data converted to our GM calibration, that is a service I can provide. I can recommend a suitable model if you aren't sure.


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[XfireZ51]

One last point. If anybody uses the ford motorsports injectors and wants the injector characterization data converted to our GM calibration, that is a service I can provide. I can recommend a suitable model if you aren't sure.


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Todd,

And just to underline the point of using that data, one "tuner" both of us respect won't tune a car without the proper bias curve.

[tpepmeie]

Banish?


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