Originally Posted by Fully_Bolted
I think the HPFP is most certainly the limitation at this point. Terry's logs show it cannot keep up with the demands, even with the Low pressure holding target perfectly. I wish we could get more information from Shiv on what they have done specifically on his car, we see the surge tank and the fuel pump, but have they tried replacing the fuel feed line with something larger from the LPFP to the inlet of the HPFP? Are they running higher than 72psi of fuel pressure on the low side?
Well, I wish I had all the answers and had a better understanding of liquid dynamics, but I don't. I know for our solution, running two LPFPs in series will cause an increase in flow volume without increasing pressure to meet the fuel demand. I posted this in another thread and had someone comment that running them in parallel was a better solution, but what they failed to realize is that doing so is not possible without major modifications to the fueling system which is not feasible. I think it's funny how some people just have nothing better to do than shoot holes in a solution with little to no knowledge of what they are talking about.
As far as I know with Shiv's solution, he still has the stock LPFP that feeds a high pressure racing fuel pump. They have a pressure regulator between that and the surge tank, which holds about 1 liter, to keep from over pressuring the surge tank. Then another pressure regulator to keep from over pressuring the line to the HPFP. It's my understanding he is still using the stock fuel lines.
For everyone who is anti Vishnu, you have to remember this is not a Vishnu solution. FFTEC fabricated this and tested this solution. That shop has produced some of the highest HP EVO's anyone has ever seen. They are not new to the world of high performance cars. Yes this is a new platform for them, but when you look at all other applications of high performance fueling solutions, the surge tank solution has been used for years on high HP fuel injected cars. We just haven't adopted the solution on our platform until now. Just watch, everyone with an opinion without any knowledge of how a surge tank works will try to punch holes through this solution. It won't be until a few people actually start using it will it become more acceptable. But honestly, how many people are going to need a surge tank so they can make 800+ whp? I personally would be happy with 600 whp and hopefully the inline booster can supply the demand.
Two years ago if someone would have told you this engine would be running on 100% e85 making as much HP as upgraded turbos made at that time you would have said that wouldn't be possible due to the limitations of the fueling system. Who's to say in the next two years with big turbos and additional fueling solutions this engine won't be making 1000 whp? We won't know until we try.