If you watched today’s dynocams you saw us we struggle with Scranton PA sledder Mark Dombrowski’s 04 Fusion fitted nicely by him with a Series 53 143N300 Aerocharger, intercooled and Boondocker boost measuring box. Mark was shooting for 200 pump gas HP. No problem.
For normally aspirated EFI mod sled it usually takes 2-2.5 hours to dial in Boondocker to perfection. The Boosted mode on this prototype Boondocker was new to me, but we dialed in A/F ratio safely at 5 psi boost in about three hours. But with perfect A/F ratio and 5 psi boost the HP and airflow CFM were only marginally higher than stock!
Turbo 2strokes normally show us 4-5 or more PSI pipe center section pressure higher than boost pressure, but this one measured 3 psi LESS than boost pressure!
After checking out the Aerocharger top to bottom, then even wiring the vane controller closed we failed to create backpressure or more than 5 psi boost.
Mark and his pal Allan (Allan brought a troublesome trail mod XCR800 to diagnose but he had a new-style clutch on an old-style crank end and we could not remove his clutch with either our new or old style pullers so no dyno tune was possible) are on there way home to Scranton.
Then I got a call from Sean Ray, on his way home from the Gaylord MI SnoX race where his Sean-tuned Tim Bender/Team Industries SnoX racers had some difficulties with a few perpexing mid-race seizures. Since I am the only person that has exceeded Sean’s personal dyno piston seizures at DynoTech he occasionally consults with me when that happens on or off the dyno. When you tune for max HP you must dance around temp, baro, fuel octane, fuel reid vapor pressure, piston clearance, etc etc. I am confident the Sean-tuned racers will be fine for the next race.
Then I discussed Mark Dombrowski’s very strange tuning session today with the Aerocharged Fusion 900. Sean has more boosted dyno tuning at DynoTech than me while we were doing Aerocharger kits next door. And Sean immediately suggested a split tuned pipe seam weld– too common on boosted stock singles. Since that seam is hidden under the stock pipe’s heat shield that is likely to be the culprit. I left a voicemail to Mark that he will get in a few hours. I’m hoping that when he pops off his heat shields tomorrow he will find the airflow/ boost/ HP robbing gap in the weld.
No dyno tomorrow I will be Mr Mom with my sick 7 year old son, Tuesday two lightly modded F7s, Wednesday Bill Looneytune DiFranco to dial in his F9 Lancaster Championship winning sled into a Canadian Trail-Safe monster with Monster single pipe and quiet stock can. Thursday I have another dyno session I can’t remember what since my calendar is back at the dyno. Thurs PM Sean Ray is supposed to bring his dad’s Fusion 600 sled (our first tuneup posted here) now poked out to 670cc and with aftermarket pipes. Sean and his family are scheduled to go to their camp in Tug Hill next weekend and it will suck to be Sean if his dad can’t ride his new sled.