the 5.3 should have multec II's.. why don't you just have them reconditioned and cleaned. 15.00 per injector. There are no other replacements except the Multec II made by Delphi. New are like 60 each.

 

1st, slick video.

Those pencil flow injectors look completely useless

But the ones with the wide spray pattern have me thinking that they would be better for port injection, or and engine where theyre close to the port like an LSX or LTX but not so good on an L98 where the injector would be spraying the walls of the runners too much.

I would be nice to see an injector tester that flows air as well, since they injectors are firing into a flowing, actually pulsing, airstream.

BTW I'm putting a blower engine together, and need to buy some injectors. I'm NOT going to run and FMU, I'll be reprogramming the ECU instead. It's a 383 with AFR heads and an S-trim Vortech. We're thinking it will put out about 700chp. So I'm thinking 70lbs injectors.

Here's the thread:
http://forums.corvetteforum.com/show....php?t=1862873

 

There is so much air flowing through the intake that the spray never actually hits the runner. However, the tiny droplets of fuel that is not atomized goes into the mixture just as fast. But they are not burned in the combustion chamber. Even in a batch fire, the atomized fuel will be mixed with air. This all happens in milliseconds. But, it is conceivable that the pencil type injector could leave puddleling on the intake valve before it opens. In looking at the newer designs in injectors. It seems like there is a push for higher pressure, and wider atomized spray patterns. As far as your blower goes. Lucas just came out with a high z 75lb. They have the new design with the 3 hole discharge. As I said before Turbo and Blowers like these type on injectors. With a blower spray patterns are not a factor. The high differences it atmospheric pressure inside the runners actually suck the fuel in as it comes out of the injector nozzle. The key to a blown motor is to give a steady supply of fuel. Just never go lean.

 

I would like to see stock ls1 injector.very nice set up for testing.

 

Great to know. I may have to go larger than the 30s I have now. Looking forward to the video! Thanks for the information

Mike

 

Great videos !!

As mentioned above as I was reading all the posts, i was wondering as well if a wide spray pattern vs pencil pattern might perform different in different types of runners. I was thinking that maybe a wide pattern would hit the walls of a rectangular port while a pencil pattern might hit the back of the hot valve and help vaporize the fuel better. I figured this since the valve is much hotter than the port walls.

Sent you a pm as well

 

Dang.................you just rained on my parade..........I just bought some multec 50 lbs and I am running 60 psi and higher ........supercharged with an fmu........up too 80 psi.........I guess there would be no differance on the flow rating....they would have the same coils?

 

I don't think anyone realizes how fast the fuel has to get out of the injector and into the cylinder ready for the ignition stroke. At idle 10 milliseconds at WOT 1 millisecond. The injectors are designed such that the gasoline is ejected towards the intake valve surface, which turns out to be really hot, and helping for the vaporization of fuel. If a pencil stream has to go from a liquid to vaporized fuel that quickly, not all will atomize. So, having an injector that has a better atomization out of the tip will get you better performance. No TPI system will atomize 100% of the fuel. There are "heavy" and "light" sides to the fuel molecules that burn at different temperatures heavy hydrocarbons vaporize at higher temps and the lighter hydrocarbons vaporize at lower temps. Therefore, much of the charge is going out your exhaust as unburned hydrocarbons. A real efficient engine believe it or not can run at 40-1 AFR. The only way this is accomplished is to put the charge of Atomized fuel directly into the cylinder right under the spark plug. This video shows the GDI Bosch injector (gasoline direct injection) that is supposed to be 99% atomized fuel at the delivery point.

 

AWESOME deal FICINJECTORS! .. Just ordered a new set to replace my originals on my 86. Can't wait to get them and throw'em on!

 

So when are those 'perfect' bosch GDI injectors available ?

 

Thanks for the info. You cleared up lots of questions I had.

 

they are now.. but you have to buy a new caddy, Audi, Mitsubisi, Pontiac Solstice Turbo.
These will never be a replacement for your TPI. The point was to show how atomization is what the manufacturers are striving for to run clean. (low emissions high performance). The next Generation of Corvette will have this technoloy To run a GDI injector you need approx 160 psi in your rail.

 

Did you try more than one multec injector at 60 psi?.............is it possable you got a bad one...........thanks for the great write up.

 

Let me know when you get a set in.

I'd like to see the video on how they flow

 

Just FYI, but GDI stands for "Gasoline Direct Injection". It's not a port-injection system.

 

every multec peuked at 60 psi. its inherent in the design. as the coils get weak they "lock up" at lower pressure.

 

these are the threads I like to see, especially by a suporting vendor.
Educating us a little on whats out there and how things work forthe noobs , not just pushing sales. Good stuff

 

here are the specs on the 50 you have. I would say not to go over 58psi.


Part Number 17113738 (OE # 17104487)
Static Flow Rate: 50.0 lb/hr @ 43.5PSI (300kPa) 525cc/min or 6.4gm/sec
Static Flow Rate: 57.7 lb/hr @ 58.0PSI (400kPa) 606cc/min or 7.4gm/sec
Dynamic Flow Rate 2.5ms pulse width and 10ms repetition rate @ 43.5PSI (300KPa): 1.1 gm/pulse
Dynamic Flow Rate 2.5ms pulse width and 10ms repetition rate @ 58.0PSI (400KPa): 1.3 gm/pulse
Coil Resistance: 12 Ohms / High Impedance / High-Z (No ECM driver modifications required)
Factory Tollerance: +/-5% (actual +/-7%)
Cone Spray Angle - 22.4 degrees - single spray cone. Approximate cone angle for 90% of spray volume
Connector: Minitimer (Bosch EV1)
Ball/Seat Design with 6-Hole Diffuser Disc
Factory fitted with Viton upper and lower o-rings. Grease supplied to lubricate o-rings prior to installation. Dynamically flowed and grouped to within 1% tolerance using Racetronix custom injector flow bench

 

Informative. Liked the video

 

Racetronix and others have been selling these injectors for many years. The Delphi 50# 17113738 injectors are very popular with Turbo Buick owners who run these injectors at elevated pressures all the time. What we are talking about here is differential pressure which the Asnu (FIC's) injector test bench will not do. The factory FL98 injector is not the same as many of the newer Multec high-performance injectors, especially the low-impedance types.

This thread seems to over-simplify certain technical facts and skew the line between injector spray pattern, atomization / droplet size. In doing so people are assuming one injector type/design is better than the next for all applications or in this case their C4. This is farthest from the truth. It is true that the newer Bosch injector designs (mostly disc-types) are better than their predecessors (pintle types). The newer Bosch injectors are catch-up technology when compared to some of the latest Siemens, Delphi and Lucas product.

It is misleading to say that a pencil-stream injector is preferred for FI but not for N/A applications.

We should also point out that one particular type of injector does not dictate the spray pattern or atomization characteristics. If you check our web page you will see that there are many injectors from the same manufacture and family with different spray patterns. There are also disc injectors which have the same body as the Delphi Multec 1 factory C4 injector: http://www.racetronix.com/01D036x.html

The C4 has very simple ECM/PCM code in comparison to the C5/C6 with far fewer injector variables used (or that can be changed) to calculate fuel delivery. The truth of the matter is there are many injectors which can be used in the C4 with little or no noticeable change to mileage or drivability.

For stock applications Racetronix recommends using an injector which is specified by the engineers at GM. This will guarantee best performance because the spray pattern and timing characteristics (which are hard coded into the ECM) will meet or exceed factory requirements.

We have received some e-mail asking us if we carry used / reconditioned injectors. Racetronix does not sell used injectors because of liability associated with this practice. The word ‘reconditioned’ has always been used ‘tongue and cheek’ here because there really is no way to recondition most top-fed MP injectors. The best one can do is flow the injector, test the coil, change the o-rings, filter basket and if applicable the pintle caps. There is no way to service the internal components. Coils break down, springs get weak and sealing surfaces wear. What tests OK on a bench today may not be tomorrow. These injectors are factory sealed and designed to be disposable. New replacement injectors are very affordable so one must weigh the cost savings vs. the risk when buying used injectors. Injector warranties are great but they don't cover a tow or motor damage.

For those who want to become ‘injector educated’ we recommend some publications available from SAE. These articles are very technical but will help dispel much of the Voodoo magic that seems to dominate this market.