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

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

Post by mk e » Tue Dec 04, 2018 9:18 am

peejay wrote:
Tue Dec 04, 2018 7:14 am

Kind of like how BMW adds a whole lot to the number for turbo engines. That newer 330 or 530 really has a turbo two-liter in it, but the older 330s and 530s had 3 liter sixes. Or 3 liter V8s, depending on year.
I have the last production year 328 with the NA 6 and wife has the last production year gkl350 with the NA 6.....they just drive better IMO.

But for sure bmw lost their way on modle-engine relationship as my 328 is a 3.0l.
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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by Truckedup » Tue Dec 04, 2018 9:53 am

peejay wrote:
Mon Dec 03, 2018 10:34 pm




The Bob Is The Oil Guy forum is full of frickin' morons who think stupid things like "oil doesn't wear out" and don't change their oil until an oil analysis tells them that the oil is used up. Of course people on their forum will have a lot of problems.

In the real world, that has people who aren't complete idiot spendthrifts, if you have a High Feature and change the oil every 3-5000mi, they last a good long time. I have a few in my care that are well, well beyond 200k km on the chainsets that GM installed on the assembly line. The common link with them all is REGULAR OIL CHANGES with GOOD OIL, period. None of this 15-20k mile ridiculousness.
There's also guys on Bob is the Oil Guy, who argue endlessly about oil additives and other [Blank Post] stuff with no real experience...I believe many Diesel OTR truck operator base oil changes from oil analysis info?

However, what's interesting about the oil anaylsis is the amount of fuel dilution in some modern engines in the a 5000-7000 mile oil change interval..On the other hand, I know bike guys using top of line synthetic oil and changing it every 1200 miles...
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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by mk e » Tue Dec 04, 2018 10:11 am

Truckedup wrote:
Tue Dec 04, 2018 9:53 am

However, what's interesting about the oil anaylsis is the amount of fuel dilution in some modern engines in the a 5000-7000 mile oil change interval..On the other hand, I know bike guys using top of line synthetic oil and changing it every 1200 miles...
O my daily driver I change it once a year whether it needs it or not....generally 20k-40k miles and the engine lives 200k+ miles no problem. I'm cheap and busy and have found engines easily outlive the body....so I stopped spending as much time and money.
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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by n2xlr8n » Tue Dec 04, 2018 2:06 pm

mk e wrote:
Tue Dec 04, 2018 10:11 am
O my daily driver I change it once a year whether it needs it or not....generally 20k-40k miles and the engine lives 200k+ miles no problem. I'm cheap and busy and have found engines easily outlive the body....so I stopped spending as much time and money.

Filter as well?

Wow. Coming from a gearhead such as yourself, that honestly surprises me, but I get the time thing.

I've pulled down modern engines that I know for a fact were abused but looked like new.
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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by mk e » Tue Dec 04, 2018 2:18 pm

n2xlr8n wrote:
Tue Dec 04, 2018 2:06 pm
mk e wrote:
Tue Dec 04, 2018 10:11 am
O my daily driver I change it once a year whether it needs it or not....generally 20k-40k miles and the engine lives 200k+ miles no problem. I'm cheap and busy and have found engines easily outlive the body....so I stopped spending as much time and money.

Filter as well?

Wow. Coming from a gearhead such as yourself, that honestly surprises me, but I get the time thing.

I've pulled down modern engines that I know for a fact were abused but looked like new.
Filter too. Oil, filter, tires usually when I drop it for inspection once a year....but I have a Jan sticker now so the color is good through next Dec before anyone is likely to notice..... I would not buy a used car from me.

I use synthetic oil and add...my bmw is about a quart each 4k so it gets 10 new plus the 5 quarts it starts with in a 40k year....so that's like a change every 13k right? It seems to work out fine.

Stuff I care about gets oil changes, the stuff I drive is just $/mile.......and oil costs $.
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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by digger » Tue Dec 04, 2018 2:55 pm

Yeah I know, it was not a serious comment

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

Post by adam728 » Tue Dec 04, 2018 8:43 pm

Oil is cheap, I change it (too) often. A 25 mpg uses 200 gallons of gas in 5,000 miles, which at $2.50/gal is $500 in fuel. An oil change during that might be $35 (on the high side).

This new twin turbo V8 is pretty impressive (as is the Ford 2.7L). I'm just amazed at what production engines are capable of now days. I currently own 2 small block Chevys, a 165 hp 350 in a 1982 G30 van, and a 190 hp TBI 350 in a 1992 C2500. So you can see why I'm amazed at the specific power output on stuff today!

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

Post by MadBill » Thu Dec 06, 2018 1:56 pm

Philosophically I'm with Adam, but operationally I'm in the Mark camp. I once changed the oil in my '03 Vibe after 37,000 km of mixed highway/city driving. I felt a little guilty about it so I had the drainings analysed. (In various cities, I've found local Amsoil distributors to be the easiest go-to guys.) The report came back "Suitable for further service." #-o

By way of contrast, after I burned a piston (don't ask) in my 3 cyl. '87 Pontiac Firefly (Chev Metro clone) the oil looked like tar after a few hundred klicks.
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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by mk e » Thu Dec 06, 2018 2:34 pm

MadBill wrote:
Thu Dec 06, 2018 1:56 pm

By way of contrast, after I burned a piston (don't ask) in my 3 cyl. '87 Pontiac Firefly (Chev Metro clone) the oil looked like tar after a few hundred klicks.
My 1st new car was an 89 Suzuki swift gt, a metro but with a big 1.3L 4 cyl and with the gt badge came a 4v head that bumped it from 70hp to 100hp! :)

Being my 1st new car it got lots of oil changes....so it was in perfect shape the day I drove it into a very large rock that pushed the perfect engine about a foot into the passenger compartment.....no good can come from changing oil :)

And this little thing is about the opposite of a Caddy with a 3.9L twin turbo v8 which I'm sure will be a joy to drive ....even in the rain.
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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by Newold1 » Fri Dec 07, 2018 9:05 am

We are drifting here.

I think some here are missing out not understanding or discussing some of the new standard engine configuration technology that has appeared in this engine.

This new 4.2L twin turbo engine is radically different in the cylinder heads.

The exhaust ports empty into the valley side of the V and the intake tract is outside of the V were the exhaust has always been on US V-8 engines.

Major change and departure for V-8 turbocharged engine coming from Detroit.

Reason and benefits are that the exhaust track is shortened to the turbo and exhaust temperature at the exhaust turbine in the turbo is kept higher.
The benefits from these two pluses allow greater work by the turbo and reduction of turbo lag. The other major benefit is a narrower width to the 90 degree V-8 package.

Just thought I would mention this pretty radical engine architecture change for those here who have not studied the features and turbo application to this new engine.

Nice to see more bold steps forward by the Detroit dinosaurs!
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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by tt 383 » Fri Dec 07, 2018 9:14 am

Newold has this been confirmed as a corporate engine that would be shared with the Vette or Caddy specific? I have seen a few rumors of a 5.5 for the Vette in both NA and FI forms. Seems odd they would develop 2 DOHC engines. Of course that's always just conjecture from an inside leak...

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

Post by Newold1 » Fri Dec 07, 2018 10:35 am

I think most now feel that until GM makes a public corporate release that any engine will appear in the Corvette is pure speculation.

There has been mention that because the DOHC engine for the new mid-engine Corvette has not been in development very long and this new 4.2L turbo V-8 has been in development over 4 years and testing for a long period that GM may use it as an interim engine for the 2020 Corvette or so until a more powerful DOHC V-8 can be ready for deployment.

Reason I think that is GM/Corvette wants the new 2020 and beyond mid-engine Corvettes to give chase to some of the more exotic mid-engine cars being delivered in that high end exotic vehicle market and with those creeping up at 800HP and beyond most realize this 4.2L twin turbo V-8 release will probably cap at about 700HP or so and not be capable of getting beyond that 800+HP level.

A 5.6L larger version of this engine with strengthening in the block can probably give that level of power with some form of vehicle warranty for the "Hot Foot" on the street! This new "Hot V" design probably will also contribute to cooling control of the new mid-engine ( Oh Heck C-8) Corvette.

The nice opportunity for GM (planned I am sure) is that they located the build place for this 4.2L engine at the Corvette Bowling Green plant. Read between the lines here and I think we might be able to see where GM is going for powertrains for the new mid-engine Corvette. :wink:
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Re: GM's new 4.2L DOHC twin turbo V-8 !!

Post by stokerboats » Fri Dec 07, 2018 5:37 pm


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

Post by Newold1 » Fri Dec 07, 2018 6:55 pm

If that is one of the variants of the new Corvette C-8 mid engine car and it sounds and handles like that there are going to be serious back orders and a ton of old Gray Beard previous Corvette ownership and quite a few new converts panting at dealerships waiting for their new ride!

Even with the camo the lines are better but still to much hard line Star Trek spaceship lines for my fancy. Smooth that damn rocket! JMO

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

Post by Ron E » Fri Dec 07, 2018 11:27 pm

The swan-song ZR1 is 2.85 seconds to 60, 6 seconds to 100 and 10.6@134 1/4 mile. 25% weight on each wheel, 1.18g skid pad.
755 HP at slightly less than 15 lbs. boost
All in for under $150K.
If a 5.6L version happens with the C8 and takes it beyond 800HP, there is a Hennessey version of the old dinosaur already available with 1200HP

So, why mid engine? not for better weight distribution, mostly because it's cool?

Why DOHC and 4V? not for more HP. Maybe because it's cool too.

Why buy a C8 if McLaren has "cool" already firmly locked up. (and they really do)

Corvette has been a leader in bang for the buck and a persistent irritation for the exotics out there. I hope GM hasn't talked themselves into yet another nearly unobtainable, nearly un-insurable, absurdly expensive to maintain mid-engine sports car just to fit in with the other guys.
We'll see. But on the bang for the buck scale the apparently antiquated ZR1 sure has the bar set way up there.

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