Compound Twin Turbo Vmax-4

Thanks for the info. Very curious on how the whole setup works. I understand the rising rate fuel pressure regulator. Now the nozzles im curious about also. Very sweet setup, wish I could use this technology in a tripple base product and be successful in a drag race situation.
 

Quadzillaracer said:
No I didn't make the NSSR Menomonie race but I will be at Forest Lake, MN on the 12th for the 3rd NSSR race. The new hood was sitting in the body shop under the heat lamps drying on Saturday, lol! It really turned out awesome, the guys had over 45-hours invested into modifying this hood and trying to re-mold and modify the shape, but it looks like a "production built" hood, absolutely flawless, IMO. I attached a photo so you can see how the atmospheric air is forced straight into the huge turbo at 170+ mph.
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This is by far the BADDEST 2 STROKE I have ever seen. Hope she flies Justin. :2strokes:
 
Well we probably shouldn't have even went, lol! We didn't get over there until 2:00pm and by the time we got the sled ready and registered it was 3pm. We made a shakedown pass as the sled was jetted to fat for 38 degrees. Went to the pits to rejet and do a secondary helix swap only to find out my case of jets were at home on the bench along with my box of helixes....ugghhh! Racing closed down at 4pm so that's how it goes. Everyrhing is done ready for Chetek.
 
Felt fine, sled handled great and very straight. I don't know what speed was and Curt didn't say, we were more worried about how the sled handled, mph wasn't a concern.

The best part of the compound setup was watching the boost gauge build 5-6 psi of boost (without a 2-step stutter or retard) @ 5000 rpm. But regardless, we were screwed without having our jets and helixes. We were blowing raw fuel/oil mix out of the dump pipe because the poor sled was jetted so fat. The carburetion on these 2-stroke turbo engines gets real challenging once its above 32 degrees.

I finally have time to work on the tune later this week so we will be ready for Chetek in 2-weeks, things look very positive on this compound setup and airflow apparrently isn't an issue with the sled making 5+ psi of boost on the line...I've never had a single setup that could build boost at the startline without some form of 2-step stutter. I'll keep everyone updated!
 
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Justin, can't wait to see this thing run in Chetek! We'll be out there racing as well and I'll definitely know when this thing is about to run. Looks great see you in Chetek!
 
Back home and all unloaded from the Weenie Roast in Cable, WI! What a great time as usual. Finally, we have the bugs worked out on the new "Compound Turbo" Vmax-4! I ended up running a 155.xxx mph in 1000' @ 38 psi of boost with a decent head wind. I didn't run until about 2pm so the track was shredded and very loose from all the chisels and trail carbides. I brought the power in slowly and didn't really get into it until half track, regardless I spun most of the track and it fish tailed at the timing lights (not a pleasant feeling)! We laughed and said we wish this would have been an NSSR track, there is no doubt we would have broke 170 mph on that run. I have come to the conclusion that you need a 1/2" lug speed track and chisels for the Roast speed run, lol! Good time had by all.

Mike Martin and the BusaMod made a few late afternoon runs as well but suffered from traction issues as well posting speeds somewhere in the 140's.
 
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New progress updates and refinements being made to our race sled for the upcoming race season. Follow our race team page below @:

http://www.facebook.com/#!/pages/Durand-Racing-Performance/115920935126537
 
what is required to turbo one of these. on my banshee i have to have my bottom end oringed bigger pins in the crank and welded cylinder? there is a vmax 4 750 forsale for 800 bucks by me i would love to build one can you pm me some info?thanks for the reply ahead of time
 
It's hard to believe that another winter season is rapidly approaching us. Seems like the ice just went off the lake a few weeks ago, and I can see small sections building along the shoreline this morning.

I've been busy over the summer working to further dial in the compound turbo setup for the 2012 season. One thing I've learned from the diesel/gas compound turbo guru's is sizing one single turbo or even twins is one task, but compounds can indeed be a true black art. Even though our time on the ice was short last season we still had great beginners success with multi-staging turbos by the time the Weenie Roast came around.

So with that I've once again resized both turbos in various configurations. After reviewing different compressor map options, I went with a much smaller and efficent Garrett GT series turbo to act as the high pressure turbo. Then I resized the A/R of the turbine housing for the large low pressure turbo, now both turbos will be operating in the most efficient ranges for their set pressure ratios. Being such a new concept especially in a 2-stroke configuration, I surmized that my high pressure turbo was to big for the initial throttle response I was looking for in this setup. I am very excited with the improved combination as I'm now seeing close to 10-psi of boost at 5,500 rpms before clutch engagement (who needs a 2-step ignition setup to build boost, lol!) Now its time to finish a few details and get some better datalogging.

If time allows in my work schedule, I think another trip out east to DynoTech Research is in the plans to see how far I can push the limits of this setup. See you guys and gals on the ice soon!

Justin Durand
 
Mills said:
Will we see you in Menomonie on 2/11/12?
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Yeah, I'm going to try for Menomonie on the 11th and for sure the NSSR Chetek event (if the weather and ice conditions cooperate). I spent much of the summer/fall further developing this compound setup and should laydown some crazy speeds in 1000'.
 
ya know i have been dragracing for many years, i hold a NHRA supercomp licence and have gone deep into the 7s and have trapped 200mph a few times but i had a steel cage around me

i am pretty sure your sled would scare the crap out of me!

awesome build though! i love it!
 
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