I thought the whole dual exhaust thing was crap too until I built one for my Buggy. I looked over the pictures on Ebay and other sites, did some research and went to the workshop and 2 hours later it was done. My Buggy is loud, and launches off the line like a rocket. My advice to anyone that wants to go with duals is to do your homework.
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Dual Exhaust
- Thread starter rndtrp
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nitrocrazy
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very nice...
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- #5
Exhaust
It's not any hotter than the original exhaust. They stopped using aluminum in house wire in the 70's because of its inability to handle changes in temp. Here is a pic of the finished exhaust.
It's not any hotter than the original exhaust. They stopped using aluminum in house wire in the 70's because of its inability to handle changes in temp. Here is a pic of the finished exhaust.
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GilBeQuick
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Re: Exhaust
From your picture it doesn't look like you did anything out of the ordinary....just put the 90's where they'd be to make it fit right. How did/do you know that that is the correct number of curves? Where did you find the information that gave you the formula for how many curves, pipe volume, where to place the pressure fitting, and how to figure that all in together to come out how it needs to be? Also, how did you plug in the info for the Force .26 in there?
I'm taking your word that it works great for you, I'm just curious how you achieved the end result in a calculated fashion like you said.
From your picture it doesn't look like you did anything out of the ordinary....just put the 90's where they'd be to make it fit right. How did/do you know that that is the correct number of curves? Where did you find the information that gave you the formula for how many curves, pipe volume, where to place the pressure fitting, and how to figure that all in together to come out how it needs to be? Also, how did you plug in the info for the Force .26 in there?
I'm taking your word that it works great for you, I'm just curious how you achieved the end result in a calculated fashion like you said.
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- #7
Exhaust
I spoke to a guy in California that makes a similar exhaust system commercially and we discused the fact that I had noticed that there was not an expansion chamber on his system. He told me that the Force 26 has enough umph to keep good pressure so that the fuel keeps flowing. I then called Ofna and they comfirmed that the engine can be run without an expansion chamber as long as there was minimal back pressure in whatever exhaust I designed. I experimented with two other designs, one of which the car would not start with, and the other would never fit under the body. This turned out to be the design that had the best of both. I'm good with my hands and I love to do research. That's what I love about this hobby.
P.S. I also fixed the link to the picture in my gallery.
I spoke to a guy in California that makes a similar exhaust system commercially and we discused the fact that I had noticed that there was not an expansion chamber on his system. He told me that the Force 26 has enough umph to keep good pressure so that the fuel keeps flowing. I then called Ofna and they comfirmed that the engine can be run without an expansion chamber as long as there was minimal back pressure in whatever exhaust I designed. I experimented with two other designs, one of which the car would not start with, and the other would never fit under the body. This turned out to be the design that had the best of both. I'm good with my hands and I love to do research. That's what I love about this hobby.
P.S. I also fixed the link to the picture in my gallery.
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Yep it looks great but I'm still unsure about needed back pressure. A properly tuned pipe has two parts, a divergent cone (positive pressure & a convergent cone (negitive pressure). The orig. positive pressure wave reaches the end of the convergent cone at the rear of the pipe. Its reflected back toward the exh. port. When the piston moves up from BDC & the transfer ports close- pressure at the exh. port changes from pos. to neg. & this burst of pressure from the rear cone is called a "plugging pulse" . Timed right, this pulse pressure pushes the "over scavenged" air & fuel mix back through the manifold & into the cylinder before the piston closes the exh. port. This increases the mix pressure in the cylinder, & is known as supercharging through the exh. port. (taken from text "Nitro Engine Guide") Without the proper tools to keep this pressure timeline correct I can't see building a dual exh. without interfearing the pressure timeline. But it looks great & I'll probably make 1 anyway
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bashmaster
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what if you left a real pipe on and just used really big pipes to route the exhaust out the back?, giving minimal backpressure
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- #10
Exhaust
That's the spirit, challenge what you see and what you read. You guys really know your stuff. I did similar research by talking to people designing and building similar systems and they were convinced that it would and did work. The short section at the first bend gathers the pressure wave and the next sharp bend reflects it back towards the pressure nipple creating a "push pull" effect mimicking the original exhaust and keeping that ever so important timing intact. This design does supercharge the motor, how's 54mph sound?:w00t:
That's the spirit, challenge what you see and what you read. You guys really know your stuff. I did similar research by talking to people designing and building similar systems and they were convinced that it would and did work. The short section at the first bend gathers the pressure wave and the next sharp bend reflects it back towards the pressure nipple creating a "push pull" effect mimicking the original exhaust and keeping that ever so important timing intact. This design does supercharge the motor, how's 54mph sound?:w00t:
skyline1999gtr
Gone - bye bye.
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could you tell me how you made that. I would like to do that.:thumbsup: thats sweet.:thumbsup: