Author Topic: 2 stroke turbo jetting  (Read 901 times)

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Offline neandethal

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2 stroke turbo jetting
« on: July 03, 2019, 06:37:31 AM »
Hope the subject caught your attention, bringing my turbocharged 2 stroke sidecar to the salt in August and all my testing has been at sea level in essence. Last year with my normally aspirated 2 stroke i reduced the main jet by 15% and got good results.
So my question is this, with the addition of boost do i need to compensate still or leave alone?? Anyone experience, i remember a Yamaha RZ350 turbo the in 2017. Thanks for any information or views. Cheers Ian

Offline salt27

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Re: 2 stroke turbo jetting
« Reply #1 on: July 03, 2019, 09:57:46 AM »
I would leave it alone.

  Don

Offline Stainless1

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Re: 2 stroke turbo jetting
« Reply #2 on: July 03, 2019, 10:22:30 AM »
draw thru or blow thru  :|
Stainless
Red Hat 228.039, 2001, 65ci, MSA Bockscar Lakester with a little N20 
MSA Bockscar Lakester #1000 my fastest mile 245 and change, 84 ci turbobusa motor... but Corey's 233 MPH H/BFL record is still 3MPH faster than mine.

Offline neandethal

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Re: 2 stroke turbo jetting
« Reply #3 on: July 03, 2019, 10:33:44 AM »
blow through, pressurized airbox, approx 8psi of boost.

Offline kiwi belly tank

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Re: 2 stroke turbo jetting
« Reply #4 on: July 03, 2019, 12:04:10 PM »
I did a turbo sled a bunch of years ago & never needed to change the jetting but had to add a fuel pump & a boost referenced regulator. Monitoring the egt's is a must if you want to keep the pistons inside.
  Sid.

Offline neandethal

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Re: 2 stroke turbo jetting
« Reply #5 on: July 04, 2019, 09:40:31 AM »
Thanks, have done those :lol:

Offline kiwi belly tank

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Re: 2 stroke turbo jetting
« Reply #6 on: July 04, 2019, 11:10:25 PM »
Send it & keep one eye on the gauge Mate! :-o
  Sid.

Offline revolutionary

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Re: 2 stroke turbo jetting
« Reply #7 on: July 05, 2019, 08:19:20 AM »
With my little 72cc sidecar scooter I have a draw through turbo 2 stroke and i ended up making big jet changes going to Bville from initial testing in TX. Also, I went from running 60mph to 49 maxed out on the salt. You'll just need to see what it wants and bring lots of jets. I use a Polini 19mm and recorded all the changes but they are in my log book at home. I can see the difference from start to finish if you want to PM me.
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Offline kiwi belly tank

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Re: 2 stroke turbo jetting
« Reply #8 on: July 05, 2019, 11:31:03 AM »
 I had a question PM'd to me on a blown application & I figured I'd address it here. I'm not a 2 stroke guru but I've spent a bunch of time messing with them, mine & others. I did my apprenticeship in New Zealand, have been racing all my adult life & earn my racing money doing 24hr breakdown service for long-haul trucks & tour buses here in the Rockies.
An EGT gauge should be considered as a "gauge", not as a safety valve because the engine & reading location's will vary per application as in turbo draw through, blow through or blown & the important thing is what's happening in the hole.
 Reading the plugs is a must but I also read the pipe. I like to see the pipe wet just out of the head & that tells me it's not too lean in the hole. Once you have that, now you know how the plug should look & have the EGT number you can call good for your setup.
 Draw through will tend to lean out as you go up & blow through will tend to go fat. EGT's will be a little higher with a turbo than a blower due to pressure stacking in the pipe.
 To save unbolting the pipe a swillion times to see if it's still wet in there, I weld in a 1/8 pipe bung so I can pull the plug & stick my cheap (fine China Harbor Freight) bore scope in there. Looking at the end of the pyrometer probe was not good enough.
 Hope this helps you 2 stroker's!
 Now to get back to my 10.45 liter twin turbo 4 stroke. :-P
  Sid.
  ps I sold my turbo sled to buy tires for my streamliner. :cry:
   
 
« Last Edit: July 05, 2019, 11:35:18 AM by kiwi belly tank »