Flat Plane V8 Race Engine - Single Exit Exhaust Question

[oneaves2005]

Hi Craig,

I have a picture of the headers, but thats it..... I can draw a diagram of the layout if required?

Ollie

[tt 383]

Any regulation on how long the single exit must be? Why can’t you run duals to a big “dump” pipe about 4 or 5 inches from exit?

[oneaves2005]

Regulations state that the exhaust must exit through a single pipe to the rear of the vehicle. The silencer width is limited by the fuel tank and leaf springs also. Also worth noting that ground clearance is an issue, no scope for a silencer any further forwards of the rear axle.....

[tt 383]

Regulations state that the exhaust must exit through a single pipe to the rear of the vehicle. The silencer width is limited by the fuel tank and leaf springs also. Also worth noting that ground clearance is an issue, no scope for a silencer any further forwards of the rear axle.....

So you couldnt squeeze 2.5inch race bullets in line in front of the axle or on/as the up pipes to go over the axle? Then merge after the axle?

[oneaves2005]

From what has been said above, it appears that there is a benefit to joining the two exit pipes into one pipe near the collectors? What would be the benefit of keeping them seperate?

[MadBill]

If it comes to choosing one of your current systems, the brown curve will definitely get you around the track faster.

[tt 383]

From what has been said above, it appears that there is a benefit to joining the two exit pipes into one pipe near the collectors? What would be the benefit of keeping them seperate?

I guess it depends on when you join them and where it would be beneficial to your application, but why run 1 silencer and apparently space limited (my view a restriction) when you can run 2?

[tt 383]

So do you have a graph of your cars power (i understand its a project thus far) or just doing this "blindly"?

[englertracing]

Those headers are probably a little too long imo
I think you should do stepped headers.
Ive got 790hp through 1 3/4 at the flange stepping to 1 7/8

[oneaves2005]

So do you have a graph of your cars power (i understand its a project thus far) or just doing this "blindly"?

So, I built the engines on both cars, and I previously had one the same spec, with the 1.75” headers, which put out the same power as the other car with 1.75” headers to within a few BHP. I sold that car a few years back, but now I’m building another... I want to get it right this time. Both exhaust systems were calculated by others not me...

[tt 383]

Those headers are probably a little too long imo
I think you should do stepped headers.
Ive got 790hp through 1 3/4 at the flange stepping to 1 7/8

Funny, I was thinking L88 side exhaust when I opened the pics up, they were grossly too long.

[cjperformance]

Regulations state that the exhaust must exit through a single pipe to the rear of the vehicle. The silencer width is limited by the fuel tank and leaf springs also. Also worth noting that ground clearance is an issue, no scope for a silencer any further forwards of the rear axle.....

Ah a little rover v8. I cant pick what body the car is? The little rover and small bay i think make the pipes look longer than they are.
Yes please draw a layout or just let us know the length from collector to the y into the single tailpipe.
Also what size is the choke at the primary/collector merge?
The main advantage to more length from collector to the single pipe particularly where diameter is on the small side is time for the gas to cool and exhaust pulses to blend/smooth out which makes the pipe 'look' bigger to the denser smoother gas flow.
The bigger pipes need flow area behind them or the lower velocity simply cant keep the gas in the small tail pipe moving.
If i had to start fresh id use the 40mm(1-5/8"), shorten up the primaries, 2"(id) choke out to 2.5 and then into the single tailpipe after the bends over the rear axle or if thats not possible as smoothly as possible before the rear axle keeping all bends as open as possible.

[BLSTIC]

Are pulse termination boxes not an option? Or is there sooner reason they would be undesirable and/or can't fit?

[dannobee]

What do the rules say regarding floor pan modifications? Can you put some version of asphalt late model crossover headers in it and fabricate a raised floorpan on the passenger side to fit a muffler and still maintain legal ground clearance?

[oneaves2005]

rough sketch of the usual arrangement below. We like to leave enough room to pull the box without removing the exhaust, but this is not essential.