Dave Tetlow
|
| posted on 3/2/06 at 03:55 PM |
|
|
V8 Exhaust Balance Tube or not!!
I am building a V8 MGB Roadster and will soon be fitting a twin SS exhaust system.
It will have to go down each side of the repositioned or modified fuel tank.
Do I fit a balance pipe to go between each system? I am told this would give a better sound.
I would appreciate any comments.
|
|
|
|
|
nitram38
|
| posted on 3/2/06 at 04:00 PM |
|
|
The only reason a cross over pipe is fitted to a v8 engine is for tuning purposes. A lot of ford v8's need a cross over, but rover v8's do
not. It has a lot to do with the firing order and the exhaust gas 'pulses'.
In a race tuned engine, each pulse of gas should slot in behind each other pulse so that there is a smooth exit for the gas.
Exiting gases can also help draw other pulses out of the exhaust. The cross over on ford engines helps with the process instead of gas pulses
fighting each other.
Most Rover v8 engines have one exhaust for each bank of cylinders.
It will still sound pretty cool!
[Edited on 3/2/06 by nitram38]
|
|
|
mark chandler
|
| posted on 3/2/06 at 04:05 PM |
|
|
Better sound, better power, its a must have, without it the car will sound like 2 four cylinder engines.
It should from memory join at the collectors and be 2/3 the diameter of the main pipe.
[Edited on 3/2/06 by mark chandler]
|
|
|
nitram38
|
| posted on 3/2/06 at 04:55 PM |
|
|
Read this article about recommended exhaust at the bottom of the article:
http://www.mgcars.org.uk/v8_conversions/rogv8.html
And then this:
http://www.roversd1.nl/sd1web/exhausttuning.html
|
|
|
carnut
|
| posted on 3/2/06 at 05:43 PM |
|
|
Is the crank a single plane or twin plane? If its single plane, you dont have a balance pipe.
|
|
|
Dave Tetlow
|
| posted on 3/2/06 at 05:48 PM |
|
|
Thanks for the feedback Gents.
I don't know what type of crank I have. Its 1971 Range Rover!!
How do I tell?
|
|
|
carnut
|
| posted on 3/2/06 at 07:02 PM |
|
|
If its a std crank then will prob be 2 plane but some aftermarket cranks for rover v8's are single plane (tvr etc).
|
|
|
minordelay
|
| posted on 3/2/06 at 09:28 PM |
|
|
Single plane engines were all ajp engines in TVR's not Rover. Balance pipe is the way to go. Best way to find the correct point is to spray the
hot down pipes with spray paint!!! and where it don't burn the pipe goes.
V8's forever if only for the sound
|
|
|
Chippy
|
| posted on 3/2/06 at 11:17 PM |
|
|
I'm pretty sure that balance pipes affect where power is delivered. With a balance pipe you get better power in the lower rev ranges, without,
its better in the higher rev ranges. I may have this the wrong way round but I don't think so.
|
|
|
NS Dev
|
| posted on 4/2/06 at 01:09 AM |
|
|
quote:
Originally posted by Chippy
I'm pretty sure that balance pipes affect where power is delivered. With a balance pipe you get better power in the lower rev ranges, without,
its better in the higher rev ranges. I may have this the wrong way round but I don't think so.
Exactly right.
With the balance pipe you are (sort of) making the equivalent of a 4-2-1 on a 4 cyl engine, whereas with seperate headers on a 2 plane crank v8 you
have 2 4-1 exhausts.
Only single plane crank in a Rover block is the AJP crank, which effectively makes it 2 4 cyl engines, hence the odd sound.
Balance pipe is a good idea, but tricky to do in many cases.
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
|
|
|
02GF74
|
| posted on 4/2/06 at 10:32 AM |
|
|
Ive read somewhere that the balance pipe is required; ofcourse it will run without one but not as well.
you can see from the firing order 1-8-4-3-6-5-7-2 that the two banks do not alternate.
|
|
|
craig1410
|
| posted on 4/2/06 at 09:59 PM |
|
|
Just to add my agreement that a balance pipe is indeed recommended on a 2 plane crank as fitted to most Rover V8 engines. I'm not using one in
my Locost due to the hassle of routing it but I would use one if I had more space. My understanding is that it is required to provide more flow for
those occasions where there are two adjacent exhaust pulses on one side of the car (ie. 8-4 & 5-7). A single plane crank would alternate side to
side so a balance pipe wouldn't be required.
I think the Westfield sEight uses one IIRC.
Cheers,
Craig.
|
|
|
Bob C
|
| posted on 5/2/06 at 06:29 PM |
|
|
An alternative that I used on my V8 mx5 (where I had similar intractable exhaust issues) was to have 2 long secondary pipes on each side. On the right
side these pair 8&6 and 4&2 whereas on the left they pair 7&3 and 5&1, so each of these secondaries gets pulses on a 5,3 beat - not
perfect but seemed best of a bad job to me when I was doing mine.
It seemed to work OK but I have no reference to compare with & have never heard of anyone else doing this.
Aesthetically I think this could be made to look fairly cool.
Bob
|
|
|
Dave Tetlow
|
 posted on 5/2/06 at 06:36 PM |
|
|
Thanks for all the help folks. I am trying to find a standard twin system first and will probable take the sellers recommendation to have a balance
pipe or not.
Does anyone know any reliable custom exhaust manufacturers?
Thanks again.
Dave
|
|
|
Simon
|
| posted on 5/2/06 at 10:55 PM |
|
|
I've not got one and it works/sounds fine!
ATB
Simon
|
|
|
NS Dev
|
| posted on 6/2/06 at 01:25 PM |
|
|
quote:
Originally posted by Bob C
An alternative that I used on my V8 mx5 (where I had similar intractable exhaust issues) was to have 2 long secondary pipes on each side. On the right
side these pair 8&6 and 4&2 whereas on the left they pair 7&3 and 5&1, so each of these secondaries gets pulses on a 5,3 beat - not
perfect but seemed best of a bad job to me when I was doing mine.
It seemed to work OK but I have no reference to compare with & have never heard of anyone else doing this.
Aesthetically I think this could be made to look fairly cool.
Bob
Interesting way to do it, sounds like a good compromise and well thought out!
Retro RWD is the way forward...........automotive fabrication, car restoration, sheetmetal work, engine conversion
retro car restoration and tuning
|
|
|
