GM's new 4.2L DOHC twin turbo V-8 !!

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Bazman
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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by Bazman » Tue Dec 11, 2018 7:30 pm

Back on topic: the new 4.2 DOHC TT has a flat plane crank.... listen to it here

https://www.lsxmag.com/news/corvette-c8 ... -at-night/

Sounds good, but not as good as the ZR1 imo, perhaps the final version will have more bass

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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by mk e » Wed Dec 12, 2018 7:40 am

Bazman wrote:
Tue Dec 11, 2018 7:30 pm
Back on topic: the new 4.2 DOHC TT has a flat plane crank.... listen to it here

https://www.lsxmag.com/news/corvette-c8 ... -at-night/

Sounds good, but not as good as the ZR1 imo, perhaps the final version will have more bass
I think that tells us for sure that there are 2 versions of the engine, Caddy and vette.

That thing seems to be revving well past the 5500rpm caddy spec and a flat crank makes sense in a vette designed to compete with Ferrari, not sure the caddy version would have that and the vibration it brings.....Ferrari builds a 90 degree crank version for the Maserati line.
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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by Newold1 » Wed Dec 12, 2018 11:22 am

Bazman

Thanks for the update on that Mercury Marine DOHC LS7 engine pricing. When they were first released a few years back they were being quoted as $75K in some articles. $33K is not cheap but I wonder if Mercury Marine is just possibly getting rid of previously built inventory. Yes, I am sure it could exceed 800HP with some tweaking and for sure turbo upgrades but that would seriously push the pricing into the stratosphere,

Thank you also for the 4.2L TT flat plain crankshaft info. See, I had not idea the engine was so designed or equipped. We all learn dailey here on Speedtalk. :)
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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by Truckedup » Wed Dec 12, 2018 12:43 pm

Mercury Marine designed and or built the DOHC V8 in the earlier ZR1 Vettes? Do you think they have a hand on the new engine?
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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by Bazman » Wed Dec 12, 2018 2:20 pm

Newold1 wrote:
Wed Dec 12, 2018 11:22 am
Bazman

Thanks for the update on that Mercury Marine DOHC LS7 engine pricing. When they were first released a few years back they were being quoted as $75K in some articles. $33K is not cheap but I wonder if Mercury Marine is just possibly getting rid of previously built inventory. Yes, I am sure it could exceed 800HP with some tweaking and for sure turbo upgrades but that would seriously push the pricing into the stratosphere,

Thank you also for the 4.2L TT flat plain crankshaft info. See, I had not idea the engine was so designed or equipped. We all learn dailey here on Speedtalk. :)
All good, I've enjoyed many of your posts and learned a lot.

Yes $33k is a lot, but it's actually good value imo. I can recall back in the 90's a really good race engine was $50k back then, but nobody I knew in the 90's was making 750hp NA that could drive daily on pump gas, last ...and do it on a cheap budget.

Even today, at 750hp NA stuff gets serious if we want durability. Cheapest way would be to buy a used NASACR and refresh it - but it'd hardly be maintenance free or daily driver friendly lol

e.g. CNC Motorsport do a 700hp pump gas LS441 for around $20k (but unlike the SB4 that excludes accessories). To handle the abuse the SB4 7.0 can and get the added 50hp while retaining street manners - that price could double without a blink.

What do you guys think? How much to build a 750hp 8000rpm daily driver.... and yeah, it has to be NA and go a year between resetting tappets and checking the springs... and what platform would you use? I'd be thinking something like a 4.5" bore short stroke Hemi just because they're strong

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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by Bazman » Wed Dec 12, 2018 2:28 pm

Truckedup wrote:
Wed Dec 12, 2018 12:43 pm
Mercury Marine designed and or built the DOHC V8 in the earlier ZR1 Vettes? Do you think they have a hand on the new engine?
Lotus (UK) designed the 32V ZR1, and Mercury built them. I'd say Mercury learned a lot from that partnership. Lotus was at that time one of the more famous Formula One brands.

Another reason why I feel that the Mercury Marine quad cam engines will be well designed. Also, if you want to see if your engine will blow up - put it in a boat. :lol: :lol:

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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by Newold1 » Wed Dec 12, 2018 3:05 pm

I have spent many years building and upgrading marine offshore endurance engines and also spent a lot of time and frustration trying to keep them running more than one race or outting. The biggest thing I learned right along with manufacturers and builders like Mercury and some others was that if you want to find out what you are doing WRONG with an engine and its build and components, put in in a boat in a racing and endurance application. When it comes back broken or in a basket you quickly see and analyse what went wrong. You usually do this many multiple times before you get a real endurance piece that stays together for at least one race and can be replicated for subsequent builds! Once you get to this point you can actually start adding more power and performance until you get to that very quick result of breakage and you end up starting all over again! :roll:

If Mercury and other good marine endurance engine builders do this well it's because they went thru the "walking on hot coals" adventure I described above! :lol:
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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by Bazman » Wed Dec 12, 2018 4:22 pm

:lol: :lol: yep.

A very good friend of mine (who does all my tuning) used to work for OMC in what was their equivalent of Skunk Works. All they'd do was run their race outboards to failure, see what happened, fix, restest, make a change, do it again... it's why they won so many races during that era. Sometimes they found things that were count-intuitive e.g. while EVERYBODY was running ports as straight as physics would allow, they found putting a 15 degree bend in the right spot gave them another 15-20hp nobody else had. Those are what you'd call the Lord of the Rings "Precious" bits of IP you don't read about on Car Craft :lol:

re boat motors - then you take them out of the boat and put them in an endurance desert race and discover heat :lol: :lol:

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