SPF Headers and side pipes

[DanMartin]

Dana, we really must meet up some time (I'm local!)

Very interesting stuff...

BTW: There's a place south of Hillsboro on 219 that sells straight gas (E-0).

[ACademic]

Does anyone know where Gas-N or Ron Roberts sources their mufflers? Are they using Classic Chambered or some other brand? And does anyone have YouTube links to either the Gas-N or Rob Roberts pipes on a car? Hearing is believing.

[Rare Iron]

Originally Posted by ACademic

Does anyone know where Gas-N or Ron Roberts sources their mufflers? Are they using Classic Chambered or some other brand? And does anyone have YouTube links to either the Gas-N or Rob Roberts pipes on a car? Hearing is believing.

Neither are buying from me.

Dana - 2" muffler cores will "easily handle" 600 HP? That is not true at all - not even close. You will see a very significant HP & torque loss through that size core with 600 HP. I wouldn't recommend using a 2" core muffler on ANY V-8 - not even a 289 2-bbl '66 Mustang.

[Dana E.]

Dana - 2" muffler cores will "easily handle" 600 HP? That is not true at all - not even close. You will see a very significant HP & torque loss through that size core with 600 HP

I'm just relaying what the builder told me: the collector, the exhaust gas temperature and velocity all play a part in how well the exhaust system works. I can't comment about the 600 HP level, but at the 500 HP level, those 2" cores were down less than 20 HP at the horsepower peak (5900 RPM) compared to the dyno headers with no mufflers. Looks like the guy just might know what he's talking about. Someone with an honest 600 HP motor will have to bolt on a set of these pipes and see what results they come up with.

I wouldn't recommend using a 2" core muffler on ANY V-8 - not even a 289 2-bbl '66 Mustang.

In the case of the GAS-N pipes, those 2" flowpath mufflers work pretty good and are somewhat quiet. They do look good and have a bit of a "crackle" to the exhaust sound.

I'm supposed to be getting a set of 2 1/2" core Gas-N pipes. I may do a before and after muffler test on a chassis dyno with the new pipes.

[mattpatt]

It's been a while and I came across this thread. Just some more info for folks. I have SPF #3033. It came with 2" mufflers (as near as I can tell by measuring the ID of the mufflers). The engine is a KC 427W (just a basic induction - 780 Quick Fuel, Air Gap manifold). Attached (I hope I did the attachment right) are the fly wheel HP/Torque curves at KC compared to the rear wheel measurements (inertial dyno in 4th gear). The torque lose across the band is about constant and doesn't show much evidence of "choking" from the exhaust (i.e., more loss as the rpm increases). The total loss across the band is about 26%. Assuming around 20 hp peak hp loss the rest of the losses account for about 20%. I would have expected more like 15% so maybe the pipes have a bit more loss (or maybe the dynos account for difference)? Anyway, it's plenty of power for me with a reasonably flat torque curve and I'm sure my neighbors wouldn't appreciate the car being louder than it already is (I set off 6 car alarms coming home from breakfast last week).

Matt