Exhaust system

[turbocon86]

I just picked up a sprint exhaust manifold and I plan to make up a stainless 2.25" exhaust system for my GT. I have a few questions.

I'm thinking of welding a mating-flange to a short adaptor to get from the 1.25" dual pipes to 2.25" pipe immediately. Would this be better or should I stick with the longer 1.25" runners and transition to 2.25" under the car?

I also plan to go all the way back with an exhaust pipe over the rear axle and connect to a Walker 22253 mufler after the axle. This is the setup used on 90's-era Camaros. Then have a wider dual exhaust out back with resonator tips. I may even move the body exhaust indents to the new outlet positions.

Thoughts? Comments?

[asdasc]

There is a ton of info here on the exhaust system. Some of it depends how stock your motor is. The general consensus is that you want to keep it exactly like it is until you get to the 'y'. Cut it off middle of the Y, then weld on 2" pipe back to a free flow straight thru performance mufler. From there go to 2 1/4 over the rear axle, and back to the middle of a U shaped pipe with resonator tips.

You can use the search button for tons more info. By the way, are you the guy that got the sprint manifold off eBay a few days ago?

[GTJIM]

The Opel exhaust set-up is very carefully thought out and works on the 'interference' principle of exhaust scavenging. The 'Sprint' manifold relies upon the secondary pipes being their correct length to work properly.
With a higher performance motor the two secondary pipes after the cast manifold can be opened up to 1.375" but must be long enough to work in the rev range the motor will be used in. I have seen a table somewhere recently in the threads here which gives the correct lengths and sizes for varying levels of tune.
Also, anything larger than 2" - except over the axle - is starting to get too big for the rest of the system. Bigger is not alway better!

[turbocon86]

Looky, looky. I do believe that this opel on ebay has a Camaro muffler setup.

[MICAH1]

Not a six cyl but a four.... count the spark plugs. That exhaust is a GT type just with the four tips instead of the two. I had a ANSA just like it.

[tekenaar]

Originally Posted by turbocon86 Looky, looky. I do believe that this opel on ebay has a Camaro muffler setup.

Sorry, but I recognize that one as a Pacesetter resonator from the late '70s, early '80s.

[tekenaar]

Originally Posted by GTJIM The Opel exhaust set-up is very carefully thought out and works on the 'interference' principle of exhaust scavenging. The 'Sprint' manifold relies upon the secondary pipes being their correct length to work properly. With a higher performance motor the two secondary pipes after the cast manifold can be opened up to 1.375" but must be long enough to work in the rev range the motor will be used in. I have seen a table somewhere recently in the threads here which gives the correct lengths and sizes for varying levels of tune. Also, anything larger than 2" - except over the axle - is starting to get too big for the rest of the system. Bigger is not alway better!

One step further . . . I wouldn't recommend over 2" exhaust for any 1.9/2.0 engine unless "full-race" and RPMs consistently in the 6000-8500 range. Remember that engines are basically 'air pumps'.

Maintaining exhaust velocity is often overlooked when looking to 'improve' exhaust systems and is a key consideration for smaller capacity (lower flow) engines, as GTJIM said. Like carbs, tendency is to 'overdo' and, here too, "Bigger is not always better!"

[jordan]

Originally Posted by turbocon86
Looky, looky. I do believe that this opel on ebay has a Camaro muffler setup.

Originally Posted by tekenaar Sorry, but I recognize that one as a Pacesetter resonator from the late '70s, early '80s.

That is an ansa resonator with quad tips C&R used to sell them back in the day, you can even see a little of the ansa sticker, I have the exact same one on my gt.

[turbocon86]

If that's a resonator then where's the muffler? It's clearly not in the stock position. There are also resonator tips on the exhaust. Why go with a resonator and resonator tips?

The Dynomax Camaro muffler (#17227) is 4.5"x9.75"x 14". This pic looks about that size.

[jordan]

The resonator in the stock position is in the back, it is basically a hollow can to block out low pitch exhaust sounds while the muffler that is right infront of the axel blocks out high pitch exhaust sounds. The addition of resonated tips on a resonator is just to futher cancel sound and take a little more of an edge off of it.

[MICAH1]

The muffler angles up under.... notice a part of the clamp pictured just under the right side of the rear resonator.

[RallyBob]

That's definitely either an Ansa or Monza (Ansa rip-off) rear resonator. The Ansa brand was pretty decent for sound and build quality (Italian made), the Monza brand (made by Pacesetter) was very spotty in terms of quality. Sometimes they fit, sometimes they didn't. They had an issue for some time with the internal holes being mis-aligned. This resulted in such a huge power loss the cars would not break 70 mph! Yuch...