Bypass on muffler.
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Member
Joined: Dec 2005
Posts: 64
From: Greece
Bypass on muffler.
Before some days I put a valve bypass on final exhaust. Look some pics:
Here is the UPS that gave me the voltage of drill.
Creation of hole.
Here is the button.
The valve.
Start with the tube. OEM was 38mm and now 42mm.
Change on first muffler.
Here the valve on the muffler.
On the car.
And finally the back side of car.
Now from 1000rpm until 2000rmp the noise is little louder from factory because the valve do not close perfect but there is about 0,5mm opening on it. When the valve is open the loud is big.
When I check it on road with chronometer I will post again.
Here is the UPS that gave me the voltage of drill.
Creation of hole.
Here is the button.
The valve.
Start with the tube. OEM was 38mm and now 42mm.
Change on first muffler.
Here the valve on the muffler.
On the car.
And finally the back side of car.
Now from 1000rpm until 2000rmp the noise is little louder from factory because the valve do not close perfect but there is about 0,5mm opening on it. When the valve is open the loud is big.
When I check it on road with chronometer I will post again.
Thread Starter
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Member
Joined: Dec 2005
Posts: 64
From: Greece
So look some tests that I did:
I did two meters on different roads but the same start point each time and I
had my watch and push the “start-stop” buttons my shelf.
Close valve:
1st road:
In 4th gear (is auto but I pushed the “7speed mode” button) from 1600rpm until limit revs(about 5500rpm) was 21,20sec. and 2nd road: 25,03sec.
Now on open valve.
1st road:
21,0sec and 2nd road: 24,39sec.
So us we can see the first road power was better about 0,20sec.
The second road there was better power too (0,64sec).
Now I did the same meters but this time I use petrol. (My car runs LPG)
Close valve
1st road:
20,32sec until limit revs.
And 2nd road:
22,77sec limit revs.
Now open valve
1st road:
19,79sec until limit revs.
2nd road:
22,69sec until limit revs.
So us we can see the first road the power was better (0,53sec) and the second road too (0,08)
Us I have said before the test I did my shelf
on a watch chronometer so this is not the best way to see the different.
Now if someday I use dyno I will post again.
Because the valve close about 98% not more so sometimes oxygen comes in tube. So if someone (exhaust emission check) stops on road to se what emission goes out from exhaust, it will see more O2 that normal (this is comes on if there is a hole in exhaust) so he will suspect something.
I did two meters on different roads but the same start point each time and I
had my watch and push the “start-stop” buttons my shelf.
Close valve:
1st road:
In 4th gear (is auto but I pushed the “7speed mode” button) from 1600rpm until limit revs(about 5500rpm) was 21,20sec. and 2nd road: 25,03sec.
Now on open valve.
1st road:
21,0sec and 2nd road: 24,39sec.
So us we can see the first road power was better about 0,20sec.
The second road there was better power too (0,64sec).
Now I did the same meters but this time I use petrol. (My car runs LPG)
Close valve
1st road:
20,32sec until limit revs.
And 2nd road:
22,77sec limit revs.
Now open valve
1st road:
19,79sec until limit revs.
2nd road:
22,69sec until limit revs.
So us we can see the first road the power was better (0,53sec) and the second road too (0,08)
Us I have said before the test I did my shelf
on a watch chronometer so this is not the best way to see the different.Now if someday I use dyno I will post again.
Originally Posted by kimo
Why you didn't just install it before the rear muffler.
Member
Joined: Nov 2005
Posts: 348
From: Egypt
Wow $400 that's too much for very little gain. I paid $320 for Hotbits header from Malaysia and shipped to Egypt and the gain is very good. You can see the diffrence at the clips that i have in youtube under Honda City Top Speed before and after the header.
Originally Posted by Kostas
About 200$ and another 200$ for exhaust work.
If you're feeling a little too crazy,someone should fab the valve in right after the header.But get a valve that doesn't leak at all.And make sure you open it up often so it doesn't carbon up.That would be too crazy!
Member
Joined: Nov 2005
Posts: 348
From: Egypt
I was just thinking of that it should be after the header, so it will be free flow like open exhaust.
Originally Posted by TotallyFit
If you're feeling a little too crazy,someone should fab the valve in right after the header.But get a valve that doesn't leak at all.And make sure you open it up often so it doesn't carbon up.That would be too crazy!
Originally Posted by TotallyFit
If you're feeling a little too crazy,someone should fab the valve in right after the header.But get a valve that doesn't leak at all.And make sure you open it up often so it doesn't carbon up.That would be too crazy!
Thread Starter
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Member
Joined: Dec 2005
Posts: 64
From: Greece
Originally Posted by kimo
Wow $400 that's too much for very little gain. I paid $320 for Hotbits header from Malaysia and shipped to Egypt and the gain is very good. You can see the diffrence at the clips that i have in youtube under Honda City Top Speed before and after the header.
Also if I chance the header like you, I will win another extra power us you told me.
Last edited by Kostas; Dec 11, 2006 at 02:36 PM.
Member
Joined: Nov 2005
Posts: 348
From: Egypt
Did you buy it from the States, but still again you should have spend the money in a better thing.
Originally Posted by Kostas
Yes but, I do not want extra noise, only power. So when i need the extra power I open the valve. So the car is quite like before because I run often on freeway.
Also if I chance the header like you, I will win another extra power us you told me.
Also if I chance the header like you, I will win another extra power us you told me.
Thread Starter
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Member
Joined: Dec 2005
Posts: 64
From: Greece
Originally Posted by kimo
Did you buy it from the States, but still again you should have spend the money in a better thing.
And I say again. I do NOT want more exhaust noise.
Kimo, I saw the video that you told us. Do you have Honda City?
Because the City has better drag coefficient, than Honda Fit(or Jazz)
Last edited by Kostas; Dec 12, 2006 at 09:19 AM.
Member
Joined: Nov 2005
Posts: 348
From: Egypt
Yes I have City 1.3L auto Idsi
Originally Posted by Kostas
I bought from Greece.
And I say again. I do NOT want more exhaust noise.
Kimo, I saw the video that you told us. Do you have Honda City?
Because the City has better drag coefficient, than Honda Fit(or Jazz)
And I say again. I do NOT want more exhaust noise.
Kimo, I saw the video that you told us. Do you have Honda City?
Because the City has better drag coefficient, than Honda Fit(or Jazz)
Thread Starter
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Member
Joined: Dec 2005
Posts: 64
From: Greece
Kimo:
Look I think that when the valve is open is like to do not have any muffler. I mean that if I had a free muffler will be the same flow like now.
Now if (IF) our vehicle has the same power, it is normally your vehicle to has more top speed, because your vehicle has better (DC) so lower resist on air.
*[on my mistake is not CD coefficient drag but DC drag coefficient that I wrote before]
Look I think that when the valve is open is like to do not have any muffler. I mean that if I had a free muffler will be the same flow like now.
Now if (IF) our vehicle has the same power, it is normally your vehicle to has more top speed, because your vehicle has better (DC) so lower resist on air.
*[on my mistake is not CD coefficient drag but DC drag coefficient that I wrote before]