Recently got my side pipes onto my '69 with a 383.

I ran them without any baffles for a couple of weeks. Sounded great and I am sure the neighbors appreciated not being late to church on Sunday but I am not sure I can run them that way all the time.

So, I put in the STS Baffles that I had. A lot quieter at idle. Only drove it once before it went in the shop, so I didn't get a true gauge of the difference.

What I am looking for is some way to be able to quickly alter the performance.

I know about drilling the holes but that is only one setting and it will also be a painful tuning process from the remove, drill, install, drive... repeat perspective.

I thought about threading the center of the pipe at the back-end and screwing a cap on. When I asked JCL (Jim) about this on his product he verified the thought that in the capped mode you would have exhaust going down the center before being forced back out the front. Potential performance loss.

Anyone come up with any interesting ways to tune the volume from wild to wilder without removing the side pipe?

Some ideas I had:
1. Thread the center pipe, but on the inside of the pipe. Then the cap would be able to be installed from the back. The issue is how to thread it from the far end of the pipe.
2. Install some sort of butterfly at the leading end of the pipe. Route a pull tab down the inside of the tube to be able to adjust open/close. A little more involved and would still likely have some problems keeping it in either configuration reliably.

Any other ideas?

Anyone else tried capping the far and and notice any difference or measure it?

Thanks,
Dave

 

Hi

I like the idea of the cap in the back end.
This seems to be the only feasable method to do anyway.

I do not think you will feel any performance decrease with the cap installed in the back versus the front.

Pressure of the exhaust gas is not very high as the baffles do not produce any backpressure. So how much backflow could there be from the pipe ? Negligable .

Good luck. Günther

 

This is my experience with auger insert mufflers, with back to back testing. Using this muffler. http://www.speedwaymotors.com/p/1736...e-Muffler.html . Car was set up with 2" primary, 3 1/2" collector into 3' mandrel bent x-pipe turndown in front of the differential. I had it setup to pull the turn down and slip the augers in and out quickly. Long story short the inserts cost 4 tenths and 5 MPH in the eight mile. IMHO spiral mufflers are going to kill alot of power, felt like I was draging an anchor, I couldn't believe it. Didn't want to believe it, but I had to believe the time slips. Look at dynomax bullets or ultraflow mufflers for a low loss system. Ron B.

 

Oh Jebus! You must be lookin' for death threats from the spiralled baffled Kool-aid drinkers!!!

 

I know the type.

 

That was the same thing that I thought.

 

Thanks guys... unfortunately I don't have any of the mufflers or the type of exhaust set up that you suggested.

Whether or not I made the right selection is not the discussion point here. I am merely trying to determine how to be able to take what I have now and get new performance capabilities without having to remove my side pipes (no place to put in an easy removal system).

 

What diameter spirals are you using?

I was pondering the same 'tuning question that you are but this is what I was told.

Spirals need to have a 4 inch diameter to work right..... less than that would be a waste of time and money

Once you have 4 inch diameter the only benefit from removing the cap is for high compression motors only. The dyno example they give showing an increase was on a high compression L88 with race gas. Are you running a comparable motor to that?

My compression is 11.2 and I was told that other than considerable more noise I would not see a worthwhile HP increase and might loose some low end torque without the caps

Doug

 

Shurshot,

Interesting feedback that I hadnt previously heard.

I am not running a motor like that but am running the 4" pipes and baffles.

Dave

 

Hi Dave

There have been a few "new ones" on this thread for me too. I had always thought everyone who had spirals was happy with them if both you and your neighbors you can live with the volume.

A lot goes on up front and bigger is always not better..... or as the team that did my head work said........ trying to catch a mouse in a rat trap makes for a fat mouse.......

If due to to much volume that the velocity has already been slowed down I do not see where spirals will be able to increase it any........ There is a guy near me (Charlotte NC) who makes a custom high velocity header for each customer that is not only stepped from 1-7/8 to 2 inch but goes from 4 pipes into 2 before a collector that starts at 3 1/2" and graduates to a 4 inch......... and that is for up 500 inch BB's and all for the sake of velocity. (SB's are smaller in diameter).......... His customers include the NASCAR hot shots so it is no surprise that he has an expensive reputation. However if I ever build the motor that I want to it will have his system on it along with spirals.

Doug

EDIT: The augers in the link posted are IMO garbage but the ones of that the OP has are the ones to have...... and worth the considerable more expense.

 

Droptop,
I am running Hooker Header Competition side pipes with STS Baffles .
Before I Iinstalled them I removed the end cap ( its only a chevy freeze plug ) and I welded 2" piece of pipe with a screw end cap that I can get to from the open end of my 4" outlet. Very easy to take off and install. I can feel the difference with the end cap installed but after 2 years of having them on I perfer running without the end caps. I am told everyday from passerbuys that my car sounds awsome. Its a little loud but I can deal with it, just turn up the radio. People turn their heads and hear me comming before they see me and I am always getting thums up. I have never been bothered by the cops ( might be because I have Disabled Veteran plates on ) but they do look, but I think its more of an admiring look. The Harleys still pass me and are a lot louder than I am. Unless you really get on it ,I like the old school sound. I have had 4 Corvettes and this is the best sounding one I have had . I have a stock 1976 L-48 Stock bought it new , my others were 1962,1965 and a 1967 they were quicker but this one is the best sounding.