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Anyone know what kind of hp boost i would receive completely eliminating cats? When i deleted all 4 on my viper i picked up 49hp. Just curious if anyone has done this to a 65 model v12. And please dont tell me about the loud noise. Because i love it. Also i plan on doing a ecu tune from Speedriven at the same time.
'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
Originally Posted by Cpt.Joe1983
Anyone know what kind of hp boost i would receive completely eliminating cats? When i deleted all 4 on my viper i picked up 49hp. Just curious if anyone has done this to a 65 model v12. And please dont tell me about the loud noise. Because i love it. Also i plan on doing a ecu tune from Speedriven at the same time.
See posts #18-22, figure around 25hp. I wouldn't touch the back sections, you may actually lose torque. If you update the turbos, maybe 3" straight back would help. But I've never been convinced of this. Search the webs and you'll find out that there is complicated math behind exhaust flow and back pressure to create power. The short answer is if it flows too freely you lose torque. And for under 700hp, I think twin 3" is too big.
And to think AMG don't know this stuff cold given their 45 years track experience is ludicrous to me. But have at it.
See posts #18-22, figure around 25hp. I wouldn't touch the back sections, you may actually lose torque. If you update the turbos, maybe 3" straight back would help. But I've never been convinced of this. Search the webs and you'll find out that there is complicated math behind exhaust flow and back pressure to create power. The short answer is if it flows too freely you lose torque. And for under 700hp, I think twin 3" is too big.
And to think AMG don't know this stuff cold given their 45 years track experience is ludicrous to me. But have at it.
Good luck. Cheers,
maw
I can tell you from real world experience, aside from your Google findings, that the car will pick up much more than 25 HP. Don't be shocked to see a 70+hp gain, given a proper intake to supply the turbos with air. Any loss of torque will be minimal and your drive train will thank you when you are still pushing over 850 ft/lbs. A "tune only" car is close to 700 at the crank. Catless downpipes put the 3" pipe to good use bringing the power up over the 750 mark.
I wouldn't doubt AMG knows this stuff cold, but lets not forget they have to warranty a car and meet federal regulation standards with production cars. At the same time, lets not forget, they left a lot on the table with a horribly designed air box on the M275s. So as much as some may know, there is always room for improvement.
'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
Originally Posted by RaceHorse
Don't be shocked to see a 70+hp gain, given a proper intake to supply the turbos with air...and your drive train will thank you when you are still pushing over 850 ft/lbs. A "tune only" car is close to 700 at the crank. Catless downpipes put the 3" pipe to good use bringing the power up over the 750 mark.
I don't recall him asking about the intake. And I see plenty of those 700hp 65 cars with broken transmissions, if that's what you call a "thank you" from your drive train.
Your points are well taken -- we all know you can turn these things into HP monsters. But that wasn't his question. Just like whether it's worth losing the everyday reliability of the car in favor of more power, also wasn't his question.
I don't recall him asking about the intake. And I see plenty of those 700hp 65 cars with broken transmissions, if that's what you call a "thank you" from your drive train.
Your points are well taken -- we all know you can turn these things into HP monsters. But that wasn't his question. Just like whether it's worth losing the everyday reliability of the car in favor of more power, also wasn't his question.
Cheers,
maw
Hey, you are totally correct, he only asked about HP gains on a catless 65 and nothing about intake. However you babbled with assumptions, and I was able to share REAL experience since I have a 65, in fact one with 3" catless downpipes. Let's face it, it's obvious he is looking for more power and IMHO an intake is needed with the downpipes. Enjoy your AMG and I'll do the same.
'06 MB S55 AMG; '04 Audi Allroad 4.2; '05 BMW M3 Conv.; '92 MB 500E
Originally Posted by RaceHorse
Hey, you are totally correct, he only asked about HP gains on a catless 65 and nothing about intake. However you babbled with assumptions, and I was able to share REAL experience since I have a 65, in fact one with 3" catless downpipes. Let's face it, it's obvious he is looking for more power and IMHO an intake is needed with the downpipes. Enjoy your AMG and I'll do the same.
So... you answered a question he didn't ask, and you're sure he's looking for information he didn't ask about, yet I'm babbling with assumptions? OK.
Original poster, you can also see post #46 in that same thread I referred you to. With a tune and 3" exhaust, Speedriven actually LOST power. They had to open up the intake side to make the 3" exhaust worthwhile. Keep in mind, that's Speedriven talking, not me.
I really appreciate all the info, the point of my question is because for the short term, my plan is to do a simple ecu tune from Speedriven, install my lowering links, then just hack off cats and mufflers. These things are all cheap, and i know what most of you are thinking..... "you bought a s65 and you're worrying about price?" Well usually i dont but at this point in my life im having a kid and budgeting for at least the next year. Then i will start down the full customisation road ( full 3" exhaust, down pipes, bigger turbos, intake, intercoolers, etc. But for now if just cutting off cats and mufflers would not hurt anything thats what i plan on doing.
Last edited by Cpt.Joe1983; Jun 29, 2015 at 02:06 AM.
2006 s65. Ford Excursion 6.0. Pontiac GTO convertible. Porsche 944 Turbo SCCA car. Wife-E550 and 968
Originally Posted by shardul
leave the mufflers on and remove the cats.
i did this. Works great. Sounds great. It scares people when I start it in a garage. My kids call my car "angry". People ask "is something is wrong with it, why is it so loud? Is your muffler broken?" ... I say "on the contrary, it is not loud, it is the quietest 800hp car around." It quiets down a bit when the car warms up, but our glass is so well insulated that its much louder outside than in...so you want to remove the cats and have someone drive the car in front of you while you follow, and I think you will agree. Keep the mufflers.
Always been tempted to get some speedriven cat less down pipes... but then id need a tune.. and then I would want a nice intake system to compliment the tune... and then some SS BOVs to compliment the intake... then I remember that it is my daily driver lol
call me crazy, but I don't see how that would work on a turbo car. you need the manifold to collect the exhaust to feed into the turbo to build boost. Headers would need a collection point which would be so far downstream they would have insane lag. straight downpipes sound pretty darn Pagini all by themselves.
Video's do not do any justice in comparison to the sound these cars make in person. Most would be shocked to know how much different (and loud) the car sounds on cold start ups echoing off of the walls in a garage. Although it doesn't smell so good, it does have a unique sound. I think most of us grew up familiar with the firing pattern of the typical American muscle V8. The extra cylinders create more of a roar not associated with a somewhat lower revving motor.
call me crazy, but I don't see how that would work on a turbo car. you need the manifold to collect the exhaust to feed into the turbo to build boost. Headers would need a collection point which would be so far downstream they would have insane lag. straight downpipes sound pretty darn Pagini all by themselves.
The Pagani Huayra has the m158, which if I'm not mistaken is similar to the m275 except it has smaller turbos and few differences. Could be easier to replicate that sound instead of the Zonda which has the n/a motor which can work with headers.
From what Ive read, seems like just down pipes and titanium straight pipes?
So since i have posted this i have cutt off my mufflers and omg does it sound so good. I have a w220 s65 and when the car was in the air i saw it had only 2 cats and 2 mufflers. No secondary cats or resonators. Everything was totally stock. So i had rhem just cutt of the mufflers as i am not ready for full exhaust yet. And it sounds amazing. Yesterday i installed some lowering links and the car looks good. Im going to adjust them a little more in the next hour then take it in for the alignment. Muffler delete was 200$ because they had to make a custom y pipe to keep stock tips. And lowering links was 100$. I will post again once i do ecu tune and exhaust with cat delete
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