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I had to figure out a mclaren with a pretty exotic exhaust that would blow those codes.
On that car, I found the new exhaust shape allowed the installer to accidentally “swap banks since both front sensors wiring could reach both both bank’s bungs.
Also found most every factory cat configuration will not tolerate the extra heat of rear mounted turbos and that the factory heat shrouding of an Aston Martin could not be enough to keep the carpets from melting.
Last edited by HowlerMonkey; Jan 4, 2023 at 03:54 PM.
I suppose that "insanely loud" is a matter of experience and opinion. My '11 V8V S has the stock muffler, Larini 200 cell cats, and the Velocity AP tune. They are extremely nice people to work with. The tune can be removed for eChecks and then reinstalled. My exhaust valves are in the open position and it really barks when started. I like it! Here is where the experience comes in. I have had two C-2's over the years with factory side exhaust, a '32 coupe with a blown hemi, and a front engine fuel dragster with a blown hemi on 90%. My Aston is pretty mild in comparison. I have my factory cats in my garage in Ohio. I will be down South until late April/early May. Email me in the spring if you are interested in them. denniscorso1911@yahoo.com
Good point, it definitely is a matter of opinion. I'm getting more used to the sound now, though I think we're getting the start dialed in. I am definitely interested in the cats when you come down south. I'll contact you. Thanks.
I had a similar exhaust setup when I bought my 2007. Quicksilver racing exhaust and high flow cats and CEL's every couple of days. And very loud!
I ended up buying a stock exhaust and keeping the high flow cats, and that combo eliminated the CEL and lets me gun around town without worrying about the noise I'm making.
It's difficult to gauge sound, but the car is now louder than you would expect from stock, but not near loud enough to get you unwanted attention.
Stock mufflers are pretty inexpensive...got mine new through Ebay from a USA dealer cleaning out their warehouse.
Just an update on everything, not that anyone cares, but it's raining here in CA so I'm just hanging out. As of right now I've got a tune on the car that deletes the CEL for a P0420 code, deletes the full cold start and gives me the full Stage 1 upgrades. I've driven the car almost 200 miles with this tune and it's been perfect. For anyone thinking of getting a tune I can't recommend Severn Tuning highly enough. One of their specialties is Vantages. This is my first tuned car, I've always been a skeptic, never really thought it would be that much of a difference, but I am now a believer. My guy went line by line through the code and was able to make the cold start tolerable, still loud, but not obnoxious, which was really the main issue I had. The car still wails when I get on it, but I control that. In terms of performance, with the sport cats and tune we're guessing maybe 40hp+ over stock (he dynoed a 30hp gain with the Stage 2 tune......they actually did two runs to verify because they couldn't believe the first run gained so much power on a tune only, which is a 93 octane tune, which I don't have so I stuck with the Stage 1 for 91 octane). Maybe more. My butt dyno tells me that it not only pulls harder but it's just buttery smooth throughout the rev range. Redline has been raised to 7500 rpm, or maybe it's 7800 rpm, can't remember exactly, but it's higher now. Above 6000 rpm this thing really pulls hard. In his words it's kinda like a 4.7 now with the tune and sport cats. Anyhow, the car is still really loud (though it sounds glorious) but I'm keeping the sport cats on for now. In about 18 mos or so it will be coming up for smog so at that time, or maybe before I need to figure out what I'm gonna do. Until then I'm just going to enjoy the car. It's a pure weekend canyon toy. From the start, even though I had the P0420 code and it took a while to get that sorted out, the car has always run flawlessly. It has 55k miles, looks like it has 5k miles and is an absolute joy.......I am a crazy car nut, get a new toy every 18 mos to 2 years. A C8 is on my radar down the road, but for now this is it. Oh, and with the cosmetic mods on the car (V12 Side skirts, custom wider wheels that are pushed to the edge of the fender well with wider tires, Maxton front splitter, custom wrap) it's one of the most gorgeous cars I've ever laid eyes on. When I take it to Cars and Coffee it gets a LOT of attention. I've owned 6 toys in the last 8 years and this one is the prettiest by far.
Can you revert back to the stock tune to test the new catalyst? Basic canned tunes like to add fuel for power. Are you trying to pass an emissions check or eliminate the CEL?
Adding fuel will reduce power. The AFR is rich for safety & catalyst protection, so removing fuel makes more power not adding it.
__________________ Stuart Dickinson Managing Director Velocity Automotive Performance Limited 206 Maple Avenue Oliver, BC Canada V2A 4W6 Office: (1)250-485-5126 www.velocityap.com
Adding fuel will reduce power. The AFR is rich for safety & catalyst protection, so removing fuel makes more power not adding it.
Agree completely. I've tuned for 13 years and factory tunes in PE are rich....plus the factory has to warranty engines for x miles and x years. Cannot get there running 12.5 AFR and leaner.
So I think I'm gonna go back to stock cats with the Stage 1 tune and CEL delete for the P0420 code. It's just not enjoyable to me driving around and having it be so loud. I'll be losing a bit of power not having the 200 cel sport cats but it will be worth it. I'm probably gonna keep the sport cats so down the road when I sell the car they can go with it.
i have hi flow hedders and 200cel cats on my v8v. it was way too loud for me also, so Chris at VAP did a tune with the exhaust valves in quiet mode all the time. now its perfect,like a stealth but nice tone.
and i have the remote cc charger exhaust valves on off mod for those days i wanna wake up the neighbours
i have hi flow hedders and 200cel cats on my v8v. it was way too loud for me also, so Chris at VAP did a tune with the exhaust valves in quiet mode all the time. now its perfect,like a stealth but nice tone.
and i have the remote cc charger exhaust valves on off mod for those days i wanna wake up the neighbours
I contacted my tuner about trying this. Thanks for the recommendation!
I fixed this on my car with mini-cat bung extension so post catalytic sensor sits behind a dense (albeit very small) cat element that's not in the path of the exhaust flow. Makes the exhaust gas proper for the sensor and avoids DTC codes. Works like a charm
There's many to choose from.
Look up prosport mini cat o2 for an example
Did you end up getting the straight spacer or the angle one?
I'll need to get a set for my car throwing P0420/P0430...
