Originally posted by NSXTech:
… And lastly, for now, to the common comment about paying a few dollars more for a better pump and injectors-it is not about money- it is about reliability and availability. There are no injectors available from Honda that meet the requirements we have, except possibly the JDM injectors that come with the Gruppe M kit, and since I turned them onto the p/n, with the CT hi-boost kit. These injectors are too big, and you must cut the fuel pressure way back to use them. If fuel pressure should increase from this number say because of an FMU failure, the engine would die a slow death from cylinder wash- I have witnessed this myself. I do not choose to use injectors from an aftermarket source because they fail too often compared to Honda injectors and I won't accept that. Cruise the Integra and Civic boards and read about the failurs of injectors from some of these companies you are so full of.
Well, I probably started the comments about the pump, but I hate to be lumped in with some of the others out here. My experience with the NSX is clearly very limited compared to yours, so now that I hear your explanation I would be less concerned if I were in the market for an SC. I also had never hear what someone else claimed above, that your system actually monitors the fuel pressure. I understand that voltage to the pump and the FPR adjust with boost, but does something else adjust according to the fuel pressure? How is that reading used? Anyway, the bottom line is, it would have been blind stupid faith on my part to assume that the original parts are up to the task and not bother to question it, particularly given my own experience with the stock pump. I’ve never been very good at blind stupid faith.
As for the follow-up question to the comments about diagnosing my own fuel pump problems, it’s quite simple. There was no need for a hi-tech means to chart fuel pressure vs flow in my case. With the fuel return line plugged I had < 90 psi at idle with the resistor removed (~14.5v), so that’s the pressure limit of the pump without an up-converter, period. With the return line still plugged I had a friend monitor a fuel pressure gauge as I ran full throttle and full boost. The pressure dropped precipitously to around 45 psi, which explained why increasing duty cycle of the auxiliary injectors didn’t help much, they simply sprayed longer at a lower pressure with little net gain in total flow. I replaced the fuel filter with no improvement. Replacing the pump completely solved the problem. So, why was my pump weaker than it apparently should be? I’m not sure, but why spend more for a voltage converter that forces an old and possibly suspect pump to work harder, and itself represents one more thing to install, one more adjustment, and one more potential point of failure, than it costs to buy a new pump with huge headroom? It wasn’t a tough decision.
So, I trust that any open minded person can see why I was concerned about using the stock pump in the Basch system, or any other trying to make that much HP. (True, the other SC kits manage, but by all appearances they make significantly less power.)
The pump I use is a Walbro 255. They just recently released an in-tank installation kit for the NSX. I don’t have the name of the vendor I used here with me but I’ll post it in a new thread this weekend. I should have done so sooner because he was SUPER helpful (I called and emailed lots of places) and I’d like to give him a plug.
Did I leave anything out?
