LT6 / C8 Z06 engine

[tpepmeie]

Well, I know Dom started a thread on this already, but I am blown away by what GM has done with the LT6. To get 670 bhp from 5.5L is astonishing. Flat plane crank, as has long been known. But, mechanical valvetrain with what appear to be finger followers. Valve sizes and cam specs not disclosed. Bore is 104.25mm, or approx 4.100". Stroke must therefore be in the range of 80.5mm (3.170") for 5.5L.

For comparison, i've calculated the hp/liter, and the BMEP at the rated peak power and peak power engine speed for a handful of the highest hp N/A engines.

LT6....121.9 hp/L....12.98 bar BMEP at 8400 rpm
Ferrari 458 Speciale.... 132.8 hp/L....13.20 bar BMEP at 9000 rpm *** Highest specific output N/A engine***

458 Italia....125 hp/L....12.43 bar BMEP at 9000 rpm
Porsche GT3 RS....130 hp/L....14.12 bar BMEP at 8250 rpm
Merc SLS AMG....100 hp/L....12.11 bar BMEP at 7400 rpm
Ferrari 430 Scuderia....117 hp/L....12.29 bar BMEP at 8500 rpm

So, it appears they have succeeded in the highest absolute hp for a N/A V8. But not quite the level of specific output of the 458 speciale, which is probably the pinnacle of production N/A engines.

For fun, a 368 LT5 would have to produce:
685 bhp on the engine dyno @ 7500 rpm to equal the BMEP of the LT6
(assuming a very conservative 4.5% difference between the steady state SAE certified conditions with full accessories and exhaust compared to the normal aftermarket Superflow STD conditions and open headers)

for a 415 LT5:
775 bhp on the engine dyno @ 7500.

for a 427 LT5:
800 bhp on the engine dyno @ 7500.

I only wish they would release this as a crate engine!!!!
Todd

[lfalzarano]

Patience Todd. Not sure it?s adaptable to a front engine layout?


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[tpepmeie]

Well, the bore spacing is the same.... maybe we could retrofit the heads and intake.... LOL

[tpepmeie]

Looks like the cams are still chain driven. The inlet port looks uncannily like the old INdy engines. Very straight and tall valve to port angle.

Saw some Bosch coils as well I think.


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[XfireZ51]

I was blown away by the engineering. And it weighs 1kg more than the LT2. Great way to tell the OHV mavens to STFU. The sealing of pairs of cylinders to take advantage of one piston going up while one comes down effectively creating an vacuum for that cylinder pair is just genius.
There?s soooo much to unpack here.

[Erik]

If it only came with a manual.....

[HAWAIIZR-1]

Originally Posted by Erik

If it only came with a manual.....

Amazing technology indeed. So much for DIY.

I agree. I guess we are old school and no sports car should have an automatic, paddle shifters or not.


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[Erik]

Originally Posted by HAWAIIZR-1

Amazing technology indeed. So much for DIY.

I agree. I guess we are old school and no sports car should have an automatic, paddle shifters or not.


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I want to drive my car, not have the computer drive it for me. This means I want to have control of the major systems, those being steering, brakes, throttle and transmission. Yes, that means I want the luxury of driving my car worse then the computer does. And the joy of driving it really well.

[1991 Corvette ZR-1]

Originally Posted by Erik

If it only came with a manual.....

You just know this will find its way into Chevrolet crate engines catalog. Although it will probably run 30K+ just for the engine. But 8600 rpm redline and 670 horses?oh yeah, I would if I could.

[HAWAIIZR-1]

Originally Posted by Erik

I want to drive my car, not have the computer drive it for me. This means I want to have control of the major systems, those being steering, brakes, throttle and transmission. Yes, that means I want the luxury of driving my car worse then the computer does. And the joy of driving it really well.

100% [emoji1360]🤙🏼


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