shhwing

I spent a lot of time reading many posts about running the 5177 dry kit without jets. I understand that the amount of gas flow is then regulated by the solenoids maximum flow rate. It was stated that running without jets is worth about 175 HP. I drilled out a set of jets and re-installed them. My test run was amazing to say the least. It pulled real hard thru 2nd and then at the top of 3rd it started surging. It never surged before with the 100HP jets. My first thought is that the FPSS is disabling the system. My fuel pressure guage never dropped below 50psi. The second run had the same surge in 3rd.

Anyone running drilled out jets experience this? For now, the 100 HP jets are going back in. It was amazing how hard the car pulled until it started surging. Any thoughts of why it is now surging?

nitrousboyWS6

iTrader: (19)

I talked to a nos tech about the max level of nitrous there powershots can spray. They said 150 and if you do not use any jets that would cause a "surging" in the spray.

shhwing

I guess he know's what he is talking about because..... it does. Oh well, the power was awsome before the surge. I keep wondering what others are doing different that are running no jets?

PREDATOR-Z

Check my sig, Multiple passes no problems. But also check my other mods, for it worked as a package.
No surging, AFR at 12.6 at peak and Timming is stock. one of the plusses here is that gasoline is 98 octane premium and I'm running TR6 gapped at .040.

What is your AFR/Timing at WOT?? what are your other mods?? Are your injectors maxed out?? What plugs are u running?? What is your gap?? Is your MAF descreened?? All of these tuning factors, not to mention weather have an effect.

Can the system run without jets? Hell ya and I got mid 11's to prove it on stock internals, tuning and no headers.

shhwing

I will answer the questions that I know the answers to, and ask how the best way is to find out what I don't know. My mod's include a whisper lid, holly air filter, de-screened and ported MAF, TR6 plugs gapped at .035", MSD 8.8 mm wires, SPEC III clutch, SLP loudmouth exhaust.

The best pump fuel here is only 91 octane. Don't know what the AFR/WOT was.. or if the injectors were maxed out. I read that even if the stock injectors were at 100% duty cycle, they are capable of supplying enough fuel while running no jets.

What is the best way to gather data needed to see timing, AFR... etc. I have a code scanner that will monitor in real time. I guess for now, I can use it and have someone else write down the numbers.

PREDATOR-Z

Autotap, LS1 edit, Predator, all can find that out or head to the nearest O2 wideband dyno and pull N/A runs, analyse data, tune and do a couple of Dyno N2O runs , then reajust again.
Usually LS1 surges on N2O when it is running lean and is not guetting enough fuel. Can't u find some racing fuel and do a little mixing for the track?

shhwing

Thanks for the help from those of you that responded. I determined that my surging was indeed caused by the FPSS. I recalibrated it by reducing the set point that causes the disconnect in current. My scanner showed that I was running a bit lean at WOT, but the surging was gone at high RPM. Having a ported MAF housing, I installed the 1K ohm resister, per the ported MAF mod, and am happy to report that all sensor readings are well within acceptable values when spraying with no jets. The pull is a night and day difference when comparing 100 HP jets to no jets. The 100 HP jets feel almost "stock" now.

PREDATOR-Z

Way to go man! I'm happy for you Just keep watching and don't take it for granted that if it works today, it will work next month. Check your plugs every few passes, and keep an eye on sudden change of weather that could make u go too lean. In the meanwhile enjoy

FIND A COBRA AND KICK HIS A** !