Landracing Forum
Tech Information => EFI Questions => Topic started by: neandethal on July 03, 2019, 07:37:31 AM
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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
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I would leave it alone.
Don
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draw thru or blow thru :|
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blow through, pressurized airbox, approx 8psi of boost.
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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.
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Thanks, have done those :lol:
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Send it & keep one eye on the gauge Mate! :-o
Sid.
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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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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: