My plugs are BRAND NEW. I have a D cable and I do want to dyno. I will call you to set it up AFTER Scott retunes.

 

Sounds good, just give me a shout. I'll take off one afternoon and we can meet down there. The place I use is where Tommy has dynoed all his big HP Supras.

 

I see the need for a higher flowing pump, but I've heard this injector story before and so has Chris Powell as he stated above. I do not believe it. If this is true, then why do the lower rated stock injectors do just fine with the 5bar FPR?

 

From the manufacturers websites:

All RC injectors (both peak & hold and saturated) have a minimum fuel pressure requirement of 30 psi (2 bar) and maximum of 100psi (6.9 bar).

Siemens Deka 60lb injectors have a listed operating range of 250 kPa (2.5 bar) to 600 kPa (6bar).

 

Chris, from what I've been told about it all this is how I figure what that means. Remember this is just me thinking out loud here. The injectors are rated to take that much pressure if it were to come to it. For example I use to make 85-90psi in fuel pressure for 15seconds in my old Supercharged Cobra with a FMU (when I had 36lb injectors) so that the car would not go lean. The injectors have to be rated for that spike of fuel pressure esp. when they are in a setup that does that. Now it does not, and correct me if I'm wrong, say that the injector is rated to flow that fuel pressure for a extended period of time. I cannot think of a good example of what to compare it to, but I think you get my idea. That it is fine for a short period of time to run at those higher rates, but it does not state their longevity at those fuel pressure rates.

 

OK then, I will correct you! Siemens Deka 60lb injectors have a listed operating range of 250 kPa (2.5 bar) to 600 kPa (6bar).

Your other reasoning seems logical but consider that the stock injectors handle 5bar just fine, and also that the fuel pressure does not stay at 5bar constantly but only when under boost.

Waiting to hear from some of the tuners why 5bar FPR and 60lb+ injectors is avoided...as contemplated earlier, is it an issue with the stock fuel pump being too weak?

 

It's probably avoided because it doesn't work. I tried it. It ran so rich I thought I had a gas leak.

 

We have seen multiple failure....not over night, but over time running 60lbs injectors with a 5bar and more then 1 bar of boost. This had held true is every make we've use them in (porsche, audi, VW).

This is what led us to discontinued the use of the 60lb injector. There are many other options out there at the same or nearly the same price that work better.

 

The one tuner that has been pretty good about posting specifics on injectors isn't posting in this thread anymore, I believe.

 

OK, I have decided to stick with the stock intake with a K&N drop in filter. Datalog this afternoon and I will send the info to Softronic.

 

God ,this thread is still going..I will have to come up with something interesting.

 

Thank you for responding!!! You are the first one to document this in our forum (someone who has seen it first hand).

Any idea why, when the stock injectors do fine? It would be silly to think that they are built to any better standards than the 60lb. This just blows my mind and I apologize if I sound like I am obsessing about it. Here goes...

It wouldn't be a pressure/leakage issue because that would also affect the stock injectors.

The other confusing thing to me is that the 5bar pressure would actually create a situation where the majority of the time, the injector would spend more time off compared to the 3.8bar FPR. The higher pressure = more fuel releases with each pulse, so less on-time except under max boost. IOW, fuel injector dead time increases with higher fuel pressures, all else being equal. Seems like that would preserve the lifetime of the injector!

Power requirement is the other variable. Perhaps the 60lb injectors have some undetermined voltage requirements at higher flow?

Well...until someone smarter than me figures it out, we will continue using the stock FPR with 60lb injectors. A shame too, it would be nice to have a simple way to get a little extra fuel.

 

I delayed my post to long.

 

It also depends on the injector body that is being used. Most on this forum are using the RC's which are based on a completely different injector body and spray pattern than that of the factory injector. One injector may hold up better than another at the high end of it's efficiency, this is one of the main reasons we also began looking into a OE style body high impudence that could handle the requirements the engine requires without having to crank the fuel pressure up.

 

Come on now, injector body style or spray pattern will not determine its reliability. I agree that maintaining the factory spray pattern is a good idea, afterall the combustion chamber/piston tops/squench area was designed using this pattern. But...a talented engine builder may have a good reason to use a different spray pattern to improve swirl and reduce detonation (this would be a very bold claim). BTW, I don't think most here are using RCs, but the same design as stock.