Tuned pipe question
02-10-2010, 06:41 AM
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Tuned pipe question
If I upgrade from a .12 to an .18, will keeping the same tuned pipe hurt the performance of the .18 too much? Thanks.
02-10-2010, 08:19 AM
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RE: Tuned pipe question
The only way to know that is to try it out. When pipe volume is too small then engine will usually run too hot and have difficulty to develop full power or "get on the pipe"
High needle settings will also be very lean and difficult. One cheap "maybe" cure is to drill out the stinger so the engine is able to blow out the exhaust and not get too much backpressure and heat.
But before any modification just try it out as it might work perfect as it is.
High needle settings will also be very lean and difficult. One cheap "maybe" cure is to drill out the stinger so the engine is able to blow out the exhaust and not get too much backpressure and heat.
But before any modification just try it out as it might work perfect as it is.
02-10-2010, 10:00 AM
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RE: Tuned pipe question
RPM will certainly shift to higher regions.
Apart from that, like flier said. You may get a surprise if you are lucky.
Apart from that, like flier said. You may get a surprise if you are lucky.
ORIGINAL: Paul1981
If I upgrade from a .12 to an .18, will keeping the same tuned pipe hurt the performance of the .18 too much? Thanks.
If I upgrade from a .12 to an .18, will keeping the same tuned pipe hurt the performance of the .18 too much? Thanks.
02-10-2010, 10:19 AM
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RE: Tuned pipe question
It all depends on the properties of the pipe on the .12 right now. For example in MACs product line their small pipe is called a .10-.15 size, so if you had one of those you already have a .15 pipe and .18 may or may not flow more than a good .15 that works with the pipe already so probably fine. Their next size up is a .20-something.
Chances are you will be fine, and as Flyer said if there is a back pressure issue then a slight increase in outlet area (slight increase - don't forget area goes up as the square of diameter) will fix that. If that is the case, the worst outcome would be maybe a hair less top end than if the pipe had higher internal volume.
And as Pe inferred the tuned length is something to consider - to use as is you need to prop the .18 to run at similar rpm. If not then like any other tuned pipe system you need to deal with that.
MJD
Chances are you will be fine, and as Flyer said if there is a back pressure issue then a slight increase in outlet area (slight increase - don't forget area goes up as the square of diameter) will fix that. If that is the case, the worst outcome would be maybe a hair less top end than if the pipe had higher internal volume.
And as Pe inferred the tuned length is something to consider - to use as is you need to prop the .18 to run at similar rpm. If not then like any other tuned pipe system you need to deal with that.
MJD
02-10-2010, 03:13 PM
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RE: Tuned pipe question
Thank you very much for all the replies guys; I think (after your advice) that I will stick with the current pipe for the moment and upgrade only if I need to. I want the extra torque from the .18 so I am not too bothered about a loss of top-end revs. Thanks again! 
02-10-2010, 07:13 PM
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RE: Tuned pipe question
You probably won't loose top rpm. I rather believe you loose low end torque.
My experience:
with the 3.5cc combat engine and using the proper tuned muffler, the engine comes alive at 13,000 and rev's up to 18000. When I then switch to the 2.5cc tuned muffler, the engine comes alive at 17,000 and revs up to 22,000.
Of course I need to use the proper propellers to allow that to happen, and adjust mixture as needed.
My experience:
with the 3.5cc combat engine and using the proper tuned muffler, the engine comes alive at 13,000 and rev's up to 18000. When I then switch to the 2.5cc tuned muffler, the engine comes alive at 17,000 and revs up to 22,000.
Of course I need to use the proper propellers to allow that to happen, and adjust mixture as needed.
