Well, race season is quickly coming to an end. Trying to get there 1 or 2 more times. Question is, any gain from dropping the intermediate pipe? My car has a stock down pipe, gutted cat and an overly restricted aftermarket replacement cat-back Walker exhaust. Want to drop down and bolt to lower holes as I have read. Is there enough clearance to do this? I'm at stock ride height.
Exhaust restriction
- Thread starter 69RSCLONE
- Start date
Mike T
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- May 3, 2013
I have a 3 inch TH downpipe, stock exhaust back to a stock style single walker muffler. On back to back dyno runs It made about 400 rwhp through the exhaust and almost 450 after uncorking it.... no other changes to the tune. I think it would depend on your hp level as to how much the exhaust would hold you back.
Mike T
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- May 3, 2013
I would tend to agree with Earl on a lower hp combo. At the track I opened up the exhaust on the old combo (same exhaust system) and had no noticeable change in et or mph. I think at a certain hp level the small exhaust reaches its limit and robs power. The dyno pulls below were made on the new combo with the same exhaust system about 5 minutes apart. The blue represents closed exhaust and the red was open.
OK. Thanks. See a lot of people with cut outs that see increases. My limitation right now is traction. I have only had a best 60' of 1.99 at 4 psi launch. Any more I spin, less I have 2.24 60'. Played with the 2-step on the TR6 and even at 1800 rpm it breaks loose as soon as I let off the button. Only had the car for 3 months, doing what I can afford right now. Just wanted to see a 12.xx this year. Best so far is 13.123 at 104.4
There's a high probability that the manifold pressure increased when you opened the exhaust. If you were to equalize manifold pressure there would be much less gained
BPE2013@hotmail.com
Mike T
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- May 3, 2013
Brian I'm not certain if you are saying that the boost pressure may have went up a bit ? Or that I have a problem with intake vs exhaust manifold pressure due to the cam? Don't want to jack this thread but I would appreciate your input.
Could be one or both.
The more restrictive the exhaust is, the more extra boost you might end up with. It takes exhaust restriction to force dump air through the wastegate orifice. When you make the 'path of least resistance easier to just go through the turbine, it's going to spin a little faster.
The more restrictive the exhaust is, the more extra boost you might end up with. It takes exhaust restriction to force dump air through the wastegate orifice. When you make the 'path of least resistance easier to just go through the turbine, it's going to spin a little faster.
Opening the exhaust probably increased the manifold pressure. To say exactly would require before and after with an accurate map sensor.
BPE2013@hotmail.com
The opposite. If you reduce exhaust pressure post turbine you will pick up a lot of flow across the turbine. More flow means more shaft speed and higher pressure ratio. Therefore you will need to waste more of the energy pre turbine to keep the manifold pressure the same
BPE2013@hotmail.com
Turbo6Smackdown
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- Dec 31, 2005
On my old combo, which was all stock but increased boost, race gas, 3" maf pipe, high flow cone filter, old hooker cat back exhaust and 245 radial t/a's, my car would beat most on the local cruise strip, when I feathered the accelerator. When I put in a dump, no amount of feathering would help my traction. My car was a TOTALLY different animal with my dump open. If I had huge slicks back then, my car would be a monster lol.
