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Has anyone got numbers (dyno or good estimates) on the changes from a stock LS5 (365hp) with and without stock mufflers? Numbers with and without air filter? My plan is to get my Vette on the dyno and maximize performance with all original parts. I don’t have data but seat of the pants seems like my air cleaner is holding things back a bit.
Likewise with the exhaust, it seems to run quite a bit better with the mufflers gone. May have to experiment some with the muff
ers?
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
2 inch exhausts choke everything , A true 2.5 front to back will improve your performance and a open 3 inch air filter with a low profile base could fit under your hood and give you a lot of clean air flow. As for actual numbers you can go to performance videos and infer what you are gaining. If you just want the performance then what I said will get you what you want. Headers would be better as well but you said stock looking
Even better would be a 2.5 chambered exhaust but they are really loud
The distributor has already been curved for my current setup. ZT9, forums can be a clumsy way to communicate but I’m not sure what you mean by dynos and getting the info needed. I just want to see the data when I make changes to verify I’m going the right direction. I’m talking about a chassis dyno, we did a limited amount of runs on an engine dyno. We were running a short, straight exhaust so I’m guessing this may affect the AFRs some?
KC
The factory style mufflers have 3 chambers. Duntov said they kill 40-50 HP on a BB.
Straight thru ones like Magnaflow, remove almost all the restriction, and sound better.
Remember the 365HP GM number was done on an engine stand dyno, the way shops do it today, with headers, no air cleaner or accessories, etc.
For 1971 only, GM rated them both ways.
Net HP is exactly as installed in the car, all accessories and exhaust, etc. But still at the crank.
I find it interesting that the SBs lost 60 measuring it that way, yet the BBs lost 80 or 100. Exhaust is huge.
So if you can remove some of that restriction, like the exhaust, you can get some of that back.
My 72 had 2.5" exhaust factory. But it still had 2.0" muffler outlets going into the tips. Not any more!
Last edited by leigh1322; Oct 5, 2024 at 09:55 PM.
Stock LS5 dyno info
