New Engine
Safety Car
Joined: Nov 2012
Posts: 4,737
Likes: 551
From: North California
I believe it is hard to make a high tech DOHC block sound as good as a simple OHV for the simple reason that there are just too many changes occurring in the combustion process. You can only tune the intake and exhaust to suit so many of the throttle positions, rpms, loads, and so on. This Porsche has 20 different sounds and while I like most of them, even the best doesn't measure up to the LT4 in the Corvette.
Race Director
Joined: Sep 2014
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I disagree. I have a Porsche V8 with variable intake runners, dual cam, variable valve phasing, variable valve lift, direct injection, high compression, and a higher redline which doesn't quite sound as good as my C7 Z06 did. It's not just the smaller 4.8L displacement.This Porsche has 20 different sounds and while I like most of them, even the best doesn't measure up to the LT4 in the Corvette.
I believe it is hard to make a high tech DOHC block sound as good as a simple OHV for the simple reason that there are just too many changes occurring in the combustion process. You can only tune the intake and exhaust to suit so many of the throttle positions, rpms, loads, and so on.
Hell, even the Dodge OHV sounds better than the Chevy.
What sounds better to one guy, may not sound better to another...so there's that too.
Racer
Joined: Dec 2017
Posts: 282
Likes: 235
From: San Francisco, CA
I personally think the current LT engines are the best sounding production V8s currently on the market. Perfect combination of raspy and racy at high RPMs but smooth on the low end. To each their own though 
Race Director
Joined: Sep 2014
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I don't know anyone who keeps the revs between 4k and 6k driving around town.
Everyone wants to shift at 2 to 2,500...
FWIW, I shift at 3 to 3.5k.
Team Owner
Joined: Sep 1999
Posts: 41,732
Likes: 1,718
From: Springfield MO
While it sounds great at WOT between 5,000 to 7,000 RPM, in daily driving I normally shift at around 2,000-2,200 RPMs as it has more than enough torque at that RPM to handle normal acceleration after upshifting.
Taking it to 3,500 RPM before shifting is just a waste of gas and adds wear and tear on the engine in my opinion.
I don't see the need to shift at 30 MPH into 2nd gear, and at 45 MPH into 3rd gear, and at 63 MPH into 4th gear, and at 81 MPH into 5th gear, and at 110 into 6th gear.
Heck, I normally shift at 55 MPH into 6th gear, not 110 MPH. My 7L V8 can handle that with out lugging.
I also don't sit at a traffic light blipping the throttle every 5-6 seconds to make noise to impress the cars around me.
Last edited by JoesC5; Jun 20, 2018 at 12:10 PM.
Team Owner
Joined: Sep 1999
Posts: 41,732
Likes: 1,718
From: Springfield MO
That 4.2L TT 550 HP engine is designed to go into a full size Cadillac sedan for us 75 year old "old farts."
Lots left in that engine. No need to go larger with it. Heck the smaller 4.0L V8 TT engine in the AMG GTR has 577 HP and is extremely mild mannered.
Now that tiny little 3.5L V6 TT that Ford has generates 647 HP and is not a full blown "race car" engine. At the same horsepower per liter that the Ford V6 has, that 4.2L TT V8 Cadillac engine should have around 770 horsepower.
Lots left in that engine. No need to go larger with it. Heck the smaller 4.0L V8 TT engine in the AMG GTR has 577 HP and is extremely mild mannered.
Now that tiny little 3.5L V6 TT that Ford has generates 647 HP and is not a full blown "race car" engine. At the same horsepower per liter that the Ford V6 has, that 4.2L TT V8 Cadillac engine should have around 770 horsepower.
Last edited by JoesC5; Jun 20, 2018 at 12:08 PM.
Instructor
Joined: Apr 2015
Posts: 239
Likes: 113
I can add that the Ford V6 at 647HP is 184HP per Liter, and Mercedes has a 2 Liter I4 that make 187HP per liter and its certified for EPA using Turbo at 26 lbs boost. Somehow they got the boost cooled so they can use pump gas too.
Sound changes with firing order but the big difference is the Turbos. Turbos have a turbine in the exhaust that reduces/smooths the gas pulses and reduces the exhaust gas temperature but over 200 degrees F. That’s part of why they take less HP to generate the same boost as a belt driven Supercharger. I have a 9 Liter engine with twin turbos/intercooled with NO mufflers and it is as quiet as a NA engine with mufflers.
BTW, I had a Z06 LS7 NA that sounded great, now a Z06/7 that I don’t like the sound at idle with exhaust open, which I have programmed, but it sounds good powered up. Maybe that’s why they come programmed to be closed/quiet below 3500 rpm or full power?
Jim
Sound changes with firing order but the big difference is the Turbos. Turbos have a turbine in the exhaust that reduces/smooths the gas pulses and reduces the exhaust gas temperature but over 200 degrees F. That’s part of why they take less HP to generate the same boost as a belt driven Supercharger. I have a 9 Liter engine with twin turbos/intercooled with NO mufflers and it is as quiet as a NA engine with mufflers.
BTW, I had a Z06 LS7 NA that sounded great, now a Z06/7 that I don’t like the sound at idle with exhaust open, which I have programmed, but it sounds good powered up. Maybe that’s why they come programmed to be closed/quiet below 3500 rpm or full power?
Jim
Race Director
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Race Director
Joined: Nov 2003
Posts: 16,066
Likes: 4,148
From: Bergen county NJ
I believe that my LS7 has the highest redline of any production engine that GM has produced. 7,000 RPM.
While it sounds great at WOT between 5,000 to 7,000 RPM, in daily driving I normally shift at around 2,000-2,200 RPMs as it has more than enough torque at that RPM to handle normal acceleration after upshifting.
Taking it to 3,500 RPM before shifting is just a waste of gas and adds wear and tear on the engine in my opinion.
I don't see the need to shift at 30 MPH into 2nd gear, and at 45 MPH into 3rd gear, and at 63 MPH into 4th gear, and at 81 MPH into 5th gear, and at 110 into 6th gear.
Heck, I normally shift at 55 MPH into 6th gear, not 110 MPH. My 7L V8 can handle that with out lugging.
I also don't sit at a traffic light blipping the throttle every 5-6 seconds to make noise to impress the cars around me.
While it sounds great at WOT between 5,000 to 7,000 RPM, in daily driving I normally shift at around 2,000-2,200 RPMs as it has more than enough torque at that RPM to handle normal acceleration after upshifting.
Taking it to 3,500 RPM before shifting is just a waste of gas and adds wear and tear on the engine in my opinion.
I don't see the need to shift at 30 MPH into 2nd gear, and at 45 MPH into 3rd gear, and at 63 MPH into 4th gear, and at 81 MPH into 5th gear, and at 110 into 6th gear.
Heck, I normally shift at 55 MPH into 6th gear, not 110 MPH. My 7L V8 can handle that with out lugging.
I also don't sit at a traffic light blipping the throttle every 5-6 seconds to make noise to impress the cars around me.
That c6 z06 of yours is awesome. Even better than the c7 z06 or zr1 and even the upcoming c8 as I’m sure once it releases you lol tell us in detail why...
I can’t wait as I enjoy your participation.
Great insights and perspectives...and I’m not being sarcastic...
Joec5 is not the man who knows the man.....Joec5 is the man!
Last edited by JerriVette; Jun 20, 2018 at 02:13 PM.
Instructor
Joined: Apr 2015
Posts: 239
Likes: 113
Burning Brakes
Joined: Feb 2018
Posts: 802
Likes: 495
From: San Francisco Bay Area CALIFORNIA
My 427 Says You're Deaf
There is no sound and physical sensation more life-affirming than a big block idling through factory side pipes.
Le Mans Master
Joined: May 2013
Posts: 5,791
Likes: 181
From: Pueblo, CO
I have a 9 Liter engine with twin turbos/intercooled with NO mufflers and it is as quiet as a NA engine with mufflers.
...
Well, it’s off topic but, it’s my full carbon fiber 4 place airplane that cruises at 322 mph at 25,000 feet in pressurized comfort. Stock Continental 550 cubic inch 350HP. Love it!!
...
Well, it’s off topic but, it’s my full carbon fiber 4 place airplane that cruises at 322 mph at 25,000 feet in pressurized comfort. Stock Continental 550 cubic inch 350HP. Love it!!
Last edited by DanSavage; Jun 20, 2018 at 03:17 PM. Reason: typo
Instructor
Joined: Apr 2015
Posts: 239
Likes: 113
I’m sure if the C8 has the “Hot V” 4.2L or 5.5L Twin Turbo the exhaust system will be much smaller, lighter, compact and sound much different. I want one!!
Here’s too 800HP cheers, Jim
Racer
Joined: Dec 2017
Posts: 282
Likes: 235
From: San Francisco, CA
No it’s not even close to Car quiet but the engine exhaust sound is not the cause of the noises. And there are many examples of the same airplanes with NA mufflered engines in the same environment and I’m convinced the NA makes more noise. My point is the Turbo’s quiet the exhaust considerably and change the sound to a smoother tone.
I’m sure if the C8 has the “Hot V” 4.2L or 5.5L Twin Turbo the exhaust system will be much smaller, lighter, compact and sound much different. I want one!!
Here’s too 800HP cheers, Jim
Race Director
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Instructor
Joined: Apr 2015
Posts: 239
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Burning Brakes
Joined: Feb 2018
Posts: 802
Likes: 495
From: San Francisco Bay Area CALIFORNIA
Safety Car
Joined: Nov 2002
Posts: 4,168
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From: FLL Florida
Last edited by Shaka; Jun 21, 2018 at 09:13 AM.
