Forcefed86

iTrader: (4)

Currently have a overly tight converter spec’d for a much larger motor.

I threw a 4.8 in the car to finish out the season while I finish building up a larger motor. With -20* of timing I can manage 4lbs of boost and 3000rpm on the trans brake. When I release the brake boost falls and the car bogs to 4k before the turbo lights off.

Recently threw a n20 dry kit on I had laying around. Using Mega Squirt to control this and cut the nitrous off at 4k. Using a .035 jet (maybe 50ish hp?) I’ve still yet to fill the bottle and plan on disabling the anti-lag/timing retard on the 2step.

Question is, if I’m still having issues. Should I just keep upping the jet size? Or should I incorporate some sort of anti-lag in addition to the nitrous? I can add or subtract as much as 40* on the brake.

Thanks

Phil99vette

iTrader: (11)

100 shot should do it.

Forcefed86

iTrader: (4)

Play time was cut short but after a little driveway testing I'm pretty optimistic. Was able to stall up past 4300 rpm and make 7psi pretty quickly. The jet was originally a 22 and I drilled it out to a 35. Looks like thats in the neighborhood of 60hp? This was with no fancy ignition tricks either. Hoping to head to the track tomorrow evening.

chuntington101

make it a 200 shot just to make sure. And spray for the whole run to help reduce intake temps.

Forcefed86

iTrader: (4)

Seems to work well. I may up the shot to 75-80. Was able to built 13lbs on the brake and hit 4800 rpm. N20 was set to come on at 2900 and off by 4100. At 4180 I was at 6lbs, engine built boost on its on from there. Worth a 1.50 60' and it was spitting rain a bit. Was on a 295 drag radial.


Pretty bad night over all though. Pulled into tech and shut down. I could hear the nitrous leaking past the solenoid into the motor. Let the car sit for 15 minutes or so. Then pulled the wires and cranked it for awhile. Then cycled the solenoid a few times. Solenoid seemed ok after that. Track got pretty crowded by then. First run was a test pass at gate pressure to see how it would act. Loaded up on fuel and botched the launch. 12.2 @ 134 on 11lbs. I shut the pressure off on the bottom WG port. This usually net me right at 20lbs. Launch was great but boost hit 29lbs and started breaking up so I let off. Third pass I opened the bottom WG port again and let 2 turns worth of boost into the top port. (guessing at this point.) Went 9.55 @144 on 18lbs. It was spitting a bit of rain at the point so I cruised home.

oakley6575

iTrader: (3)

Why are you at -20* of timing on the brake? Have you ever tried going the other way to get up on the converter. 30*+ and a lean AFR on the brake will help that 4.8L to get up on the converter and should build boost easier in an auto. Ask me how I know

Forcefed86

iTrader: (4)

I tried 40* of advance as well. It did make roughly the same boost but took longer. Retarding the timing has always worked better on all my cars. Most just don't go far enough to get it really "poppin". I'm not even using the 2-step with the nitrous at this point.

As soon as Im over 4k it builds boost on it's own. It's just not happening without nitrous on this converter. If I had the "right" converter for a 4.8 I could get away with ADV/RET timing on the two step just fine.