speaker upgrade in 67 coupe - pics

[Shawn]

He he...finally got the new sound system installed in the rat ride. We installed a few other needed items during the process.






Sorry for the dirty car...I waited until 6:00 AM when (I thought) the winter melt off would be frozen...not so lucky.

The 67 (in a container) arrives April 27th at the SeaTac docks. I arrive SeaTac airport at 6:00 AM April 29th. The shipping company opens at 7:00 AM and then the 15 hours of Le Monterey begins.

You guys have no idea how happy this makes me.

edit: flight time change. Oh, and TT...thank you for all your help. The rear torsions just slipped right out...they were fully greased...amazing. Still working on the rear sway bar set up.

[70SATMan]

Man that looks GREAT! Shawn. Time to wake the neighbors!

What's the mufflers make? Did you paint or as it came?

[Shawn]

Ha! It's for waking your neighbors! Micheal, that is the Dansk dual sport muffler. It did come painted black like that. I cut the 14" long "pea shooters" down by about 7".

I do have another less obnoxious muffler for my nieghbors.

Shawn.

[Chris Tallon]

Shawn,

Look forward to seeing you and the car in Monterey. I too have the SS Dansk muffler on my car and plan to cut the pipes down. How did you cut them? I've seen it done with a pipe cutter, but it leaves an obnoxcious ring where the pipe cutter wheel runs around the pipe.

I'm also curious if the pump settings need to change as the pipe lengths have been changed. I'm guessing Dansk engineered the pipes that long for a reason. Any thoughts?

Thanks

Chris Tallon

[Shawn]

Chris, a lightwieght pipe cutter with about three layers of electrical tape did the trick. The tape reduced the ring effect...it is nearly indetectable. This muffler is mild rather than stainless steel. That could be the difference.

My car is carbed so, no effect for me. However, when combined with a less restrictive intake system like, oh...ITG foam air filters and plates, the carbs were wanting a rejet.

I don't understand why the muffler pipes come that long. I doubt there is a performance loss or gain when shortened. I sure can't feel a difference. I did set off fewer car alarms before I cut them down.

Shawn.

[JCR]

Shawn,

Ha! Looks GREAT!

The NW coast wildlife are in for one hell of a disturbance as you blast by! Should have no problem outrunning the Prius driving, fist waving treehuggers that will be chasing you!

Wish I could be there.

[70SATMan]

The length of pipe has an affect with the resonance of the exhaust along with the back pressure seen at the inlet of the pipe.

The sound being a frequency travels in varying wavelengths. The open end of the pipe actually creates a matching impedance for some wavelengths and a mismatch for others.

It's the same characteristics that are used by transmitting Radio Frequency energy through hollow waveguide and out to transmitting antennas.

The black box designing of low restrictive mufflers and headers while maintaining low dB levels is pretty neat wild stuff. . . The sound pressure can actually affect the exhaust pressure.

Looking forward to hearing you roar past Aptos down 1. I'll probably hear you all the way from Santa Cruz!!

TTFN (with the requisite golf clap)

[Shawn]

So, for larger displacement engines, the final length of the muffler outlets could prove benificial to the engines performance.

I know my little 2.0 gained impressive hp from the equal length SSI manifold/heat exchangers. (This also removed another hp restriction that I am certain everyone here is tired of reading about)

I learned years ago from hot rodding Harley V twins that correct length for back pressure resonance can greatly assist with exhaust valve operation and produce performance gains.

However, your thoughts are that post muffler tuning by outlet length could provide results? Sounds reasonable, but we can't be talking about a lot of hp change left on the table...are we?

Shawn.

[70SATMan]

Probably not as much but, what goes into the muffler has to get out. Pressure changes on the outlet pipes affects the muffler inlets. To much low flow can cause scavenging through the exhaust valves and rob power from the combustion.

It would be interesting to design a muffler with telescoping outlet pipes and tune it on a dyno while watching the bhp and monitoring dB levels at the same time.

[70SATMan]

Probably not as much but, what goes into the muffler has to get out. Pressure changes on the outlet pipes affects the muffler inlets.

It would be interesting to design a muffler with telescoping outlet pipes and tune it on a dyno while watching the bhp and monitoring dB levels at the same time.