Don Terrill’s Speed-Talk

Anyone run them verses other performance mufflers? Any HP differences?

I put a scat back spintec on my 3rd gen. I had a flow master on it. Driving it, felt no difference. I like the sound better. Crisp and throaty.

I have clips of both if interested.

econo racer wrote: ↑Fri Jan 10, 2020 10:51 am Anyone run them verses other performance mufflers? Any HP differences?

Years ago when we were required to run our own 3" mufflers in the Engine Masters Competition we dyno tested at least ten different makes and models of mufflers, (including Spintecs), for power; (sound level was not an issue).

Anything which was not "almost straight through" was considerably down on power. We ended up going with "Extreme Mufflers". The longest available, (about an 18 inch case), made the most power and were quieter than most.

A guy in Wisc. where i race has Spintec's on a 70 Chevelle with a 540. Darn thing is so quiet you can't hear it going down the track. Seen that car run 9.90's in the past.

Motortrendondemand did a dyno test of several types of $40 mufflers on their Engine Masters show. The test engine was a Ford 351C stretched out to 408ci making just over 600 hp.

The 'straight through' mufflers cost very little power, if any. The chambered mufflers cost quite a bit, and the turbos even more. I'd say the Spintech would be right in with the chambered units. They did charts with average power between 5000 and 6800 rpm, ranking the mufflers in power. The last graph is the winners from each category... open headers, straight through, chambered and turbo.

Jones, Flow FX by Flowmaster and Cherry Bomb were the straight through mufflers for less than $40 at Summit. All were stainless steel, and made pretty much the same power as no mufflers at all. They said all three looked like the exact same muffler from the same manufacturer.

You lose quite a bit of power by going to something that is not straight through!

If you have motortrend on demand, here is the link.
https://www.motortrendondemand.com/deta ... _9y8xgnob/

Will need to click on the pics to expand them and be able to see the info.
They talk about sound and loudness in the video.

Straight Through Muffler vs. Straight Pipe


Chambered


Turbo


Graph of winners from each category

I did a test from collector extensions to h pipe with bullets vs x pipe alone vs x pipe with Dynomax straight through to adding tail pipes on this car with a nitrous 377 and never lost any et or mph, in the vid it has a 421 on a 225 shot, ran the same with and without tail pipes. I never ran anything other than Dynomax after that, although there are some good knockoffs out now.