Started by Petrus, June 25, 2022, 11:18
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Quote from: Petrus on June 25, 2022, 11:18Is there any hard data, as in méasured results, concerning gutting the precats?The internet ´info´ is that gutting prevents piston ring damage/ oil consumption and results in extra powah.The oil/ring myth I will leave aside as impossible to prove either way, but what about the powah?!The theory is that gutting the chambers sabotages the design and should overal redúce the efficiency of the exhaust.Apart from slightly more noise the result should be negligible but negative.I have been looking for before end after dyno but ... Have any of you found factual data?
Quote from: Carolyn on June 25, 2022, 11:47So it's the oil consumption that comes first.
QuoteGutting the pre-cats leaves a couple of empty cans acting as expanding gas containers and, if anything, slowing the exhaust gasses down - a bit.
QuoteI can't imagine anybody wanting to spend the money to do the dyno experiment.
Quote from: shnazzle on June 25, 2022, 17:22I definitely noticed a choke at the top end with gutted pre-cats. My theory was the same as Carolyn's many moons ago. It doesn't make any sense to gut them, for the price of a cheap Toyo manifold off email without pre-cats.
Quote from: Petrus on June 25, 2022, 17:41The myth though is still going strong on the internet with first time owners being advised to gut to prevent possible catastrophic engine damage for early and late models alike. Not a single enquiry whether the thing uses oil or not. Ah well.