Preproduction 2009 Arctic Cat Z1 Turbo

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Louisa Wilson
6 years ago
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1 Preproduction 2009 Arctic Cat Z1 Turbo D&D Powersports tech support guy Glenn Hall brought this Z1 Turbo to test stock and with power adding components that he and D&D are developing for sale this year. PA SkiDoo/ Cat dealer Billy Howard came along to help wrench, gather data, and entertain. This is one of the Z1 preproduction sleds demonstrated last season, with plenty of tough miles on it including this summer s asphalt testing by Glenn. The tiny ball bearing Mitsubishi turbo is unbelievably quick-spooling creating meaningful boost even at fast idle with no load! The ECU on the sled controls boost electronically, and we can see from our baseline test that it appears that Cat desires to limit low RPM boost, feeding it gradually until max boost is created near the HP peak. According to Glenn Hall, the stock ECU is programmed to increase boost as barometer drops. So at 1000 ft (baro was the day of the test) we saw 24 inches of mercury (12 psi) stock boost readings at the HP peak. At high altitude, boost is increased to (at least partially) maintain absolute (baro plus boost) pressure. But since that absolute manifold pressure drops even as turbo boost is increased, less fuel is needed. So as boost rises to partially compensate, fuel flow is reduced accordingly to maintain the correct A/F ratio. D&D s boost control is electronic and works fine, even creating a flat boost curve from low revs to high. But since the ECU has a declining fuel curve as boost rises, a separate fuel enrichment is necessary. At the dyno this required tweaking, but Glenn says they have plans for a toggle or rotary-switch deal that will be easy to adjust as conditions/ octane dictate. But anyone contemplating adding boost/ fuel to their sled should utilize a wideband A/F ratio meter to be sure. The following dyno test data has wideband A/F ratio readings (LAMAF1) from our Innovate O2 sensor. On this engine the Innovate readings were more than one point richer reading than the mechanical A/F dyno readings (A/FA-B) which I trust more than the wideband. Glenn s own wideband in the datalogger on the sled read somewhere between the two. Those who tune boost and fuel in the field with a wideband would be smart to measure their A/F bone stock, then just try to maintain that A/F reading as boost is increased and/ or airflow adding mufflers are used. There is detonation protection on the engine, but it is better tune properly and cautiously, and not to depend upon those electronics. Sean Ray operates an engine development dyno cel at Dephi, and even though they have the most advanced electronic deto sensors affixed to each test engine, all cels are fitted with crude mechanical copper tubing listening devices to detect deto that the electronics might miss (like the one he installed here). If Sean doesn t totally depend upon electronic deto sensors, neither should we. There have been many instances of different brands of two-stroke sleds, supposedly protected by deto sensors, that have detonated and seized pistons. The Z1 s stock tuning is designed to be reliable on low octane pump gas, operated at high temps and high speed for long periods of time. So those who are reasonable in length of time at full throttle, and who will treat their machines with respect and octane, adding HP by tuning boost and fuel is a viable option. For this tuning session, we used 93 (hopefully) octane gas from the car wash down the street. Dyno test time seconds at WOT on each run. Intercooler was cooled by 80mph airflow from the

2 roofmounted blower (at 80 degrees F this day). In all tests where airflow readings are absent, the testing was done with the hood pod in place. Unlike the F1000, the Z1 has a pod with both air inlets wide open, creating airflow adequate for 250 plus HP. We also noted while warming up the coolant at light load midrange, cruising BSFC appeared to be excellent, sub-.40 lb/hphr assuring good fuel mileage when the throttle is used judiciously. As the following dyno data shows, that BSFC drops into the low.50 s lb/hphr at WOT HP peak, fatter and safer there but still much lower consumption than the two-strokes. Z1 Turbo, bone stock baseline (93 octane pump gas) EngSpd STPTrq STPPwr BSFA-B FulA-B Air 2 A/FA-B LAMAF1 BOOST RPM Clb-ft CHp lb/hph lb/hr scfm Ratio Ratio IN HG

3 We installed a lighter weight prototype D&D turbo muffler, which added a few db and nine CFM of airflow at peak revs (4% airflow increase = 4% HP increase). Note that the lower restriction of the D&D muffler made the most gain in airflow and HP at high revs where backpressure is greatest. Z1 Turbo, remove stock muffler install D&D turbo muffler (93 octane pump gas) EngSpd STPTrq STPPwr BSFA-B FulA-B Air 2 A/FA-B LAMAF1 BOOST RPM Clb-ft CHp lb/hph lb/hr scfm Ratio Ratio IN HG

4 We reinstalled the stock muffler. Confident that our 93 octane gas and 20 seconds at WOT was reasonable, we turned up the boost to 15.5 psi, and added fuel to keep A/F ratio close to stock. Z1 Turbo, reinstall stock muffler add 3 psi boost, add fuel (93 octane pump gas) EngSpd STPTrq STPPwr BSFA-B FulA-B FuelP AirTmp LAMAF1 BOOST RPM Clb-ft CHp lb/hph lb/hr psig degf Ratio IN HG We reinstalled the D&D turbo muffler, and added 10 HP (that quiet stock muffler s restriction becomes more telling as boost rises). That 10 HP is partly caused by slight leaning of A/F ratio and the slight increase in boost pressure as the result of the reduced restriction (we left fuel flow as it was with the stock muffler).

5 Z1 Turbo, install D&D turbo muffler with added boost and fuel (93 octane gas) EngSpd STPTrq STPPwr BSFA-B FulA-B FuelP AirTmp LAMAF1 BOOST RPM Clb-ft CHp lb/hph lb/hr psig degf Ratio IN HG continued..

6 Back to the stock muffler, we drained the pump gas and added a mix of pump and race gas. Glenn bumped the boost pressure to 18.5 psi, and added some fuel. Here the stock muffler s whisper sound became more like that of a NASCAR wet track jet drier, with high velocity exhaust blasting the deck of the dyno table. It s very pleasing to be able to make nearly 230 HP, and still be legal on any trail. Z1 Turbo, reinstall stock muffler, increase boost higher for 100 plus octane fuel EngSpd STPTrq STPPwr BSFA-B FulA-B FuelP AirTmp LAMAF1 BOOST RPM Clb-ft CHp lb/hph lb/hr psig degf Ratio IN HG We installed the D&D muffler again and the results were as before, 10 HP added even with extra fuel to compensate for the higher airflow. A few more db, lighter weight and nine more HP. Z1 Turbo, D&D turbo muffler, add fuel, 100 plus octane boost level EngSpd STPTrq STPPwr BSFA-B FulA-B FuelP AirTmp LAMAF1 BOOST RPM Clb-ft CHp lb/hph lb/hr psig degf Ratio IN HG

7 Finally we installed Glenn s straight unmuffled drag pipe he runs on the asphalt. The drag pipe, used in conjunction with a less restrictive pipe from the turbine outlet to the muffler or straight pipe, eliminated virtually all of the outlet restriction and added more airflow. We tweaked boost until the turbo had its tongue hanging out, and dialed fuel up and down until HP was at its absolute maximum in this hot, humid air. We made about eight passes at 257 HP, and this final one at 258 with the airflow meter fitted to the airbox. There was no more HP to be had this day, but this was especially rewarding to be able to add 74 HP for such a small investment in time and electronic components, and $30 worth of good gas. Not one hint of deto from the computer, not a puff of oil smoke to be seen. Good tuning and proper octane can reward turbo owners with great enjoyment with reliability. Z1 Turbo, straight drag pipe, add boost and lean fuel to max HP 110 plus octane EngSpd STPTrq STPPwr BSFA-B FulA-B Air 2 A/FA-B LAMAF1 BOOST RPM Clb-ft CHp lb/hph lb/hr scfm Ratio Ratio IN HG

FULL POWER PERFORMANCE SKIDOO 4TEK STAGE II TURBO SYSTEM Jim Czekala

FULL POWER PERFORMANCE SKIDOO 4TEK STAGE II TURBO SYSTEM Jim Czekala Justin Fuller of Full Power Performance recently completed turbo size/ intercooler size/ boost range and fuel calibration of his Stage