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richierich Samba Member
Joined: December 23, 2004 Posts: 887
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Posted: Thu May 02, 2019 12:21 am Post subject: Re: Is this fuel starvation or something else? |
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nsracing wrote: |
What size venturis are in the IDAs? I would guess they are too big for the street.
For drag engines, you can go larger on the chokes. But for street use, gotta go smaller. Otherwise, you will lose all the pressure differential across the throats when you open them to atmospheric pressure instantly.
Put another way, you will stop pulling fuel when the pressure equalizes above and below the throttle plates. Hence the stumble. Gotta have that negative pressure to pull fuel and feed the motor.
My 2 cents. |
42 vents. |
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nsracing Samba Member
Joined: November 16, 2003 Posts: 9437 Location: NOVA
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Posted: Thu May 02, 2019 12:37 am Post subject: Re: Is this fuel starvation or something else? |
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42mm chokes barely got lip on there. It is a gaping hole.
Maybe give John/ACN and see what he says. I would think you need to be in the 34mm - 36mm chokes. Even 32mm will work. But you gotta have a way to tune the combo. It will be nice if you have EGTs or better yet a dyno session with the said venturis. |
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Slow 1200 Samba Member
Joined: July 02, 2004 Posts: 2103
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Posted: Thu May 02, 2019 2:45 am Post subject: Re: Is this fuel starvation or something else? |
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if it does it even in 1st gear i don't think fuel starvation is the issue |
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richierich Samba Member
Joined: December 23, 2004 Posts: 887
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Posted: Thu May 02, 2019 10:10 am Post subject: Re: Is this fuel starvation or something else? |
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nsracing wrote: |
42mm chokes barely got lip on there. It is a gaping hole.
Maybe give John/ACN and see what he says. I would think you need to be in the 34mm - 36mm chokes. Even 32mm will work. But you gotta have a way to tune the combo. It will be nice if you have EGTs or better yet a dyno session with the said venturis. |
It has been on the dyno and been tuned with the 42's in it. It was running fine but something is wrong somewhere since I fitted the rev limiter and changed ignition. I'm thinking I may have an electrical issue. |
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Dauz Samba Member
Joined: January 05, 2010 Posts: 1790
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Posted: Thu May 02, 2019 11:19 am Post subject: Re: Is this fuel starvation or something else? |
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My neighbor was troubleshooting an issue where he'd floor his throttle and when it climbed in rpm it stopped building power (seemingly) at around 4k. He thought it was ignition or fuel. We pulled his motor and found his flywheel had blued/burnt and his clutch was slipping at higher rpm. |
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