2.5” muffler question
 

Asking here because the exhaust section doesn’t get a lot of traffic.

Can you take a pair of 2.5” dynomax ultra flows (17222) mufflers and open them up to fit 3” exhaust? I was looking at these mufflers in person and it appears that they have 3” (or very close to 3”) internals. Wondering if anyone has done this or knows if the internal baffling is the same diameter between the 2.5” & 3” mufflers.

I ran a pair of the same 2.5: Dynomax Ultra Flow (17222) mufflers with a JR flat collector set of headers, 3.5" collectors, 3.5" head pipes (almost to the mufflers), and reduced down to the 2.5" (very short) opening at the front face of the mufflers. "Down turns" right after the mufflers.

The exhaust was designed like a Holley carb center main body: Large front section, venturi,
then an expansion into the muffler.

I saw very little difference in power between the open collector performance and the closed exhaust.
It will be interesting to see how much different the VOE mufflers are with the 3" stainless head pipes
I have from the HO Racing Tri-Y headers going on the car in the near future.

Tom V.

Try it and see what you come up with.

Another solution would be to use a set of cone reducers from 3 inch to 2.5 inch.

You can go to most any auto parts store and get an exhaust reducer. Just read what the reducer actually is as some will state the OD dimension and others the ID dimension. Just slip them on and then muffler clamp or weld them together.

My guess on baffling is that if 2 mufflers are the same external dimensions, that the baffling will be the same, just different pipe size for your hook-ups.

Interesting setups. I have heard about guys doing 3” from the manifolds to the mufflers and using a reducer form 3”-2.5”I do like that idea.
I was asking about opening up my mufflers because I came across a good deal on a flowmaster 1041 3” system for my car.

When Flow Master was sponsoring some of the SCCA Club Racing in the Michigan/Ohio area (where I was a member and later Regional Executive), we had MANDATED NOISE LIMITS and we did sound checks on the vehicles on the tracks.

What I saw with the flowmaster stuff was that they could not hit the sound restriction accurately on every application. They could get close but sometimes they had to "trade" mufflers with a racer with a lower noise set of mufflers from
their trailer of parts.

In your case you have no sound restrictions but it might be a flip of the coin if you are happy with the exhaust sound at the end of the day from the flowmaster mufflers.

Tom V.

The flowmaster 1041 kit does not come with mufflers. I love the sound of the dynomax ultra flows. Going to stay with them
Not a fan of flowmaster mufflers

Well that's no fun.

In the old days, at Waterford Michigan Road Race Course, there were not sound restrictions. Then the people started building subdivisions in the area and lots of people wound up living within sound distance of the track.

So then when a race was held they started complaining to the city officials who represented that area. So the racing was limited to a race once a month.

Then even that deal was not good enough for the owners of the homes so the track had to put up sound barriers. And finally the SCCA had to monitor and lower the sound readings of any vehicle that exceeded the noise standard during a race. So flowmaster came up with the plan where we the Track and SCCA officials would record the noise and tell Flowmaster what the numbers were and they would install mufflers that just met the sound requirements during the races. So then we could race for the weekend. ROYAL PIA but the only way to keep the local officials from banning racing at the track.

That also applied to the Grand Prix races in the city of Detroit. Sound limits.

I quit after 13 years with the SCCA region leaders.

Tom V.

That is the main reason that the US Summer Nationals are no longer held at Englishtown Raceway Park, Englishtown NJ. Not sure but I think the track is closed to drag racing. It was the track that Pontiac Magazine would hold their day. Houses moved in knowing the track was there but then they want the track closed. What came first the chicken or the egg.

My opinion is IF you buy a piece of property, lets say from a farmer in the country and the closest neighbors are 1 mile away and turn it into a drag strip, then you have first rights to the use of that property. Same deal with a place like the Norwalk Race Track (Summit Raceway Park). You had first rights to the use of that property.

So if a low-life Real Estate guy buys some property close by the track and sells it to a new owner as a part of a sub division, then the new owner did not do his homework on what he was getting into buying right next to a race track. BUT MONEY TALKS AND TAXES TALK with the county executives. MORE PEOPLE IN A SUB DIVISION MORE TAXES VS SAY A RACE TRACK.

In Waterford Michigan's race track case, the Home buyers may not have ever researched that the new subdivision they were building a house in was right by a race track.
Because the Track only raced one week-end out of a month for years and years.

So once the papers are signed with the builder, buyer beware.

Tom V.