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I went to the test and tune this weekend with some friends and something I wanted to test was the cutouts I added to the exhaust. After a handful of runs getting the timing and the jetting dialed in to the point that I was happy with, I opened the cutouts. The exhaust system on the car is long tubes into a 3" y pipe into a single 3" chambered muffler and tailpipe. I knew this would be restrictive, but I wanted a stock look and relatively quiet highway cruising. The cutouts are 3" diameter and installed after each header and dump out under the doors.
I was very happy with the results!
In a car that weighs 4700 lbs with me in it, 2 miles an hour in the 1/8 is pretty substantial.
It's a single 3" which is why it's such a big gain.
not really..if your single 3” is actually free flowing like you say.. it’ll handle way more power than you’re making.
a single three inch properly designed with a straight through muffler will handle 500 to 600 hp
you aren’t making anywhere near that by the weight and MPH and open exhaust
Last edited by CANADIANOLDS; September 23rd, 2024 at 04:29 PM.
60' was the same regardless. Getting traction is the challenge on the 60'
no, it wasn’t the same. Your quicker 60’ was with it closed , 2.0167 vs open 2.0281
thats .0114 which is significant. I’m saying if it’s that much better closed, there is even more in it open. you didn’t say if you changed any tuning open vs closed. if that’s the case, then you need to work on the open exhaust tuning to get back the 60’ loss. it should pick up everywhere…not a worse 60’ but better everywhere else
Last edited by CANADIANOLDS; September 24th, 2024 at 03:21 PM.
no, it wasn’t the same. Your quicker 60’ was with it closed , 2.0167 vs open 2.0281
thats .0114 which is significant. I’m saying if it’s that much better closed, there is even more in it open. you didn’t say if you changed any tuning open vs closed. if that’s the case, then you need to work on the open exhaust tuning to get back the 60’ loss. it should pick up everywhere…not a worse 60’ but better everywhere else
For these two runs, yes. But across all the runs I did that night, the cut outs did not have a measurable effect on 60'. The variation came down to my ability to launch without spinning tires.
For these two runs, yes. But across all the runs I did that night, the cut outs did not have a measurable effect on 60'. The variation came down to my ability to launch without spinning tires.
its 4,700 lbs and you can’t get traction? what tires?
its 4,700 lbs and you can’t get traction? what tires?
Ha ha, I know.
They're just cheap all-season tires. This isn't a drag car and I'm not a racer, the whole point of going to the test and tune was to see how restrictive the chambered muffler was. The whole car is just for fun and learning really. I wanted to know so I welded in some cutouts and went to see the MPH difference. The next experiment is going to be cutting out the chambered muffler and welding in a straight through style. Then I also have a couple of other converters on the shelf I want to try.
September 16th, 2024, 10:37 AM
