TRD 7th injector kit vs. URD

[Ian]

I noticed that now the 3.4 liter S/C (for the Toyota Forerunner) has as an option from TRD for a 7th injector to add to their S/C. It is supposed to add another 25% increase in hp. I am wondering:

1. Do you know or think they will have this option for our 3.0 liter S/C?

2. With the recent talk of the URD kit, which kit would be better for improving S/C performance, the URD kit or TRD 7th injector kit? I am thinking in terms of safety, reliability and performance.

[Turbosolara]

I am not too sure, but i think if you are running returnless fuel system, you will need extensive modification for the 7th injector. it might be easier just use larger injectors with computer

[JoeB]

Ian, I'm sure my opinion will come accross as biased because I was the one to prototype the URD solution for our platform but I don't think the 7th injector kit is as good a solution as the URD solution. If by chance Gadget or another knowledgable person reads this, maybe they can explain better, I'm not expert. My understanding is the 7th injector kit will definitely be an improvement over no fuel system upgrade. If you notice, it does a small part of what the URD solution accomplishes. It gives a little more fuel until more total volume is required and it adjusts the timing some. One of the benefits of that solution is the 7th injector injects fuel directly into the sc housing creating a cooling effect. The temp there gets very high and is a limiting factor as you try to decrease the pully size attempting to increase the boost. So the intercooling effect of the 7th injector is definitely an advantage but there are other ways to accomplish that (stay tuned ). The problem is our weak little 90LPH (I think) fuel pump will not deliver sufficient fuel for the application even with the 7th injector and there is no larger capacity fuel pump in the kit. It will probably be sufficient for the TRD stock 4psi pulley but what most of us are after is the ability to safely boost past 4psi.

The URD solution increases the size of the fuel injectors, increases the capacity of the fuel pump, allows you to adjust the timing and allows it to be adjusted as you modify components. This way the solution works well for people who want to push for higher boost rather than offering a solution simply geared towards making the stock 4psi supercharger run better and not blow the knock sensors. The only thing missing is the intercooling effect which in my opinion is definitely needed to safely increase the boost. As I mentioned, stay tuned.... Hope it helps. -JoeB

[Ian]

Sounds good. I think I understand the difference now.