I just installed my "make it fit" WetJet Kraze pipe and a Westcoast head with 31cc domes. I'm going to throw on my new intake manifold, OceanPro Vortex F/A and 46mm carb next. So what jetting do you think for 4000' above sea level with my new modifications? Right now the carb has factory Wetjet Kraze jetting (117 low, 155high 1.5 needle). i was thinking about changing to the needle to 2.3 and set pop off at around 20lbs. Thanks for your help!!!
Jetting for high attitude Blaster
- Thread starter 98yota
- Start date
Fro Diesel
creative control
- Location
- Kzoo
I run 130 pilot 18psi 155 main 2.0ns
Fro Diesel
creative control
- Location
- Kzoo
Not sure I usually try a couple of jets with a tach and leave things 1 and 1 for the most part.
Fro Diesel
creative control
- Location
- Kzoo
Bpipe, wetjet carb, stock flame arrestor only one screen
Do you think running a single screen would warrant going up in jetting the same amount as running an OceanPro Vortex? I know running a single screen would open up the flow of air. I also forgot to mention I removed the choke plate from my carb and am running a primer. Thanks again for your help!
Here's my carb (choke plate had not been removed yet) and the stock intake manifold I modified to increase flow. I ported the manifold and reed plate to flow air seemlessly to the case. I know there are better manifolds out there but I wanted to improve the stock design. This is a budget "make it fit" kind of build!
Attachments
Fro Diesel
creative control
- Location
- Kzoo
You could use a wetjet intake.
- Location
- Pueblo, CO
I always like to help on altitude questions (I'm at 4700ft) - here's my standard advice:
- Start with a good sea-level jetting spec.
- Bump your compression. If you go to a interchangeable dome head, go about 3cc less for your 4000ft than the recommended sea-level dome.
- Drop your impeller pitch one degree from the recommended sea-level prop. (ie: 10/18 go down to 9/17)
- Run it... You might be surprised that you'll only need to turn screws to dial it in a bit.
The factory jetting on a WetJet Kraze is 117low, 155 high. I have all of the parts off of a Kraze. I do have the Westcoast head which I guess only some of the Kraze's came with. So the only real change is the OceanPro Vortex intake and the 4000 ft altitude. Should I keep the jetting the same? Or go with the 130low, 150high 2.0 needle 18lbs popoff. I already have these other jets.
So I ordered a few sizes of jets to have on hand during tuning. I have the stock 117 pilot jet and ordered a 120,122.5,125, and 130. For the main I have a 140,142.5,145,150, and the stock 155. For needle and seats, I have a 1.5, 2.0, 2.3 and 2.5 on hand. I have several sets of all four popoff springs. I'm hoping I have enough parts on hand to get this thing dialed in!!! There's nothing worse than getting close and having to wait for parts! We've all been there!!!!
Quinc
Buy a Superjet
- Location
- California
Going off my experience at 4500+ feet I would start with:
18-21 pop off
127.5 pilot
155 Main
Having said that I rode my stock wetjet duo at 4500ft and it ran great with the stock jetting and pop off.
18-21 pop off
127.5 pilot
155 Main
Having said that I rode my stock wetjet duo at 4500ft and it ran great with the stock jetting and pop off.
- Location
- Pueblo, CO
This is probably a good starting point, but I would guess you might have to drop the main down to a 150... just a guess. There is no "one answer" to this. You need to start somewhere and give it a try.
I'm surprised the main is so big on the wetjet. I'm wondering if this is a function of the pipe or a heavily loaded hull with too small an engine? (or both). I assume the WB hull will not load the engine as hard as the Duo. . FPP Blaster Mod B-pipe jetting is 145 main, 120 pilot on a 44mm carb. I have a hard time believing that the wetjet pipe + 46mm carb needs so much more fuel! Just talking out loud here..
Go test it!