[gman]

Will this work or is it a waste of time? I have a 73 Formula with 428 72cc E-Heads RA4 cam with 1.65 HS rollers. Holly Street dominator intake (which needs to be ported)I have not made the Carb choise yet. What I want is a very quite car that can still run in the 12's. Is this possable?

[gman]

Will this work or is it a waste of time? I have a 73 Formula with 428 72cc E-Heads RA4 cam with 1.65 HS rollers. Holly Street dominator intake (which needs to be ported)I have not made the Carb choise yet. What I want is a very quite car that can still run in the 12's. Is this possable?

[Tim Corcoran]

Sounds like a nice combo. Sure it's possible. Make sure you use a mandrel bent
2-1/2 exhaust system and Walker Dynomax Super Turbo mufflers. Sounds like your already in the ball park. I'd run a 800 DP Holley. The Holley manifold is a good one to use. Just port match it and blend it back in.

Tim Corcoran

[This message has been edited by Tim Corcoran (edited 04-27-2000).]

[mike nixon]

nothing against the walker mufflers but i'd use flow master 3 chambers. i own cars with both brands on them and the flowmasters are definitely quieter. mike

[Tim Corcoran]

Mike,

I could be all wet on this but it seems that there have been extensive testing comparing the Flowmasters, Walkers and other brands also. The tests were detailed in HPP a while back. The parameters tested were back pressure, noise levels, 1/4 mile times, 1/4 mile MPH etc. If my memory serves me correctly the Walkers Dynomax Super Turbo mufflers were quieter than the 3 chamber Flowmasters and out performed them. That is the reason I recommended them. Was it the Walker 177749 mufflers that were louder than the Flowmasters?

Tim Corcoran

[mike nixon]

TIM ,those are the culprits. 72 455 2 1/2" dual exhaust on a 72 g/p with manifolds ,vs 70 396/402 bbc in a 78 chevy 4x4 with 2 1/2" headers and a 4spd. even under a 10,000lb load the flowmasters are definitely quieter than the dynomax units. nothing against the walkers they've taken alot of abuse and lasted many years but even when they were new they were louder than the flow masters. mike

[Tim Corcoran]

Mike, I have to politely dissagree with your evaluation of the Walker Dynamax Super Turbo Mufflers (17749) over the Flowmaster 3 chambers. The testing clearly demonstrates the Flowmasters had higher sound levels, more back pressure, slower 1/4 mile times and a lower MPH over the Walkers. If you look at the extensive testing done on both of these systems it just doesn't add up. Go to: http://www.wauknet.com/douhitt/exhaust.htm
Also your comparison of one system on a BBC and the other on a Pontiac is a poor comparison at best. Even a different camshaft in the same motor can effect sound levels significantly. If the test was done on the same motor with the same exhaust system and only the mufflers changed I would give some merit to your comparison. look at the tests done on the web site and you will see where I am coming from.

Tim Corcoran

[mike nixon]

tim ,with all due respect to your opinion ;i have read the hpp article, the day i got the mag. as for the results their perf tests may well be true on their application. what i was posting was info to help the man make an informed decision from my experience. after working in a gm dealer for 10 yrs and as an independent repair shop for 15 yrs now i do understand the difference in engines ,displacement, app.ect.
what i have found to be true in my experience is the greater the load level at a given rpm the greater the noise level will be for any engine.
my tow veh. gets alot more load put on it than my car ever does.and at any given rpm the truck is quieter to the ear than the pontiac ever was or will be at the same rpm with the walkers, regardless of load. one other thing to consider is that the truck has headers which in my past experience will make an exhaust tone louder due to less resriction/more airflow.
the thing that i didn't understand about the test result was the decible level from the two different styles of mufflers. the walker is basicly a straight pipe with a series of holes in it bent into a s inside the muffler,unless they have changed the design since i purchased mine. the flowmaster is a series of chambers/ baffles that are supposed to muffle the sound by redirecting it so that it will cancel itself out.at least this is the way that i understand the info in their pamphlet. the walker should flow more and produce more noise. the flowmaster may have a bit more restriction but it should be quieter due to this. the man stated that noise was a factor.
we really aren't comparing apples to apples here as far as muffler design.
the exhaust systems on both of my vehicles are pretty similar as far as muffler placement from the manifolds/headers and tailpipe length,h-pipes ect. compression ratios in both engines is the same [at least the advertised compression per piston design] so short of head design and displacement the setups are close.
like i said previously this info was my personal experience on street driven vehicles not an engine on a dyno.
i've also found that test info is a base line to start from and that it sometimes will differ from real life.
hopefully we have given enough info from both sides for an informed decision to be made. as for this particular topic i'm through posting.
mike
one possibly deaf enthusist
with tired fingers

[T Hutchinson]

Comming in late to this post but heres my experience: 68 Firebird, 428 #16's unported, cam was 238@ .050/.520 lift, factory long branch RA exhaust manifolds, 2 1/2 exhaust, Dynomax super turbo's. Chngd to Hooker 1 3/4 headers and sound both inside and outside of car DECREASED noticeably. This probably had more to do with tone rather than actual decible level as the manifolds were much deeper and resonant than the headers. The outer casings on both Dynomax Super Turbo's vibrated loose and began to rattle after 3 years of daily driving (not bad, but not great either) so I switched to Flowmaster TWO chambers which were louder to a small degree. I will add that the sound with the Dynomax was not as "crackily" (for lack of a better word) as the Flowmasters and seemed smoother with a deeper tone.

[David Holmberg]

I have Flowmasters (2 chamber) on the 77 and they sound fairly quiet on the street, but will let everyone know when you hit the throttle. I also have 3in Dyno max race mag's on my truck (460) and in everyday driving they are much louder than the flowmasters. Which one is better????? As for the Dyno Max super turbos, I know they are much quieter and respect Jims test's of them.