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6.2 L86 vs 2018 Corvette engine

SRT8dan

By SRT8dan
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SRT8dan Enthusiast

SRT8dan

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After numerous searches I am still at zero.  I am trying to find out what the difference is between my 6.2 L86 2018 Silverado engine and the same year Corvette engine that lists identical specs, but puts out considerably more power.  Is just in the cam specs, or in the exhaust, or the throttle body?  The LT2 Corvette now makes 496 HP and 470 ft lbs or torque.  I know LT2 has revised intake runners (all the same length), a revised AF sensor, low restriction exhaust, dry sump lubrication, and a revised cam.  It is still basically a LT1 engine that gained 75 HP and 10 ft lbs of torque, an 18% power gain.  The LT1 Corvette engine had 40 more HP than My L86.  What made the additional horse power. Can anyone shed some light?  Thanks.

CamGTP Senior Enthusiast

CamGTP

Posted
Posted

Likely the camshaft, intake manifold and tuning.

 

The car intake shifts the power band and so would the camshaft. The calibration for ignition timing and fueling is much different on the corvette compared to a truck.

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Salsa De Piña Enthusiast

Salsa De Piña

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The Corvette is making that power at 6450 RPM, while the trucks redline at 6000.  I'm thinking two things come into play: the Vettes are more high-strung because reliability isn't as much of a concern as the trucks and the LT2 probably uses different materials/dimensions for the rotating assemblies and valve trains to keep mass down (ex: they have hollow and sodium filled valves.)  Unfortunately, we know they're using the same valve springs...

truckguy82 Senior Enthusiast

truckguy82

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Posted (edited)
13 hours ago, SRT8dan said:

After numerous searches I am still at zero.  I am trying to find out what the difference is between my 6.2 L86 2018 Silverado engine and the same year Corvette engine that lists identical specs, but puts out considerably more power.  Is just in the cam specs, or in the exhaust, or the throttle body?  The LT2 Corvette now makes 496 HP and 470 ft lbs or torque.  I know LT2 has revised intake runners (all the same length), a revised AF sensor, low restriction exhaust, dry sump lubrication, and a revised cam.  It is still basically a LT1 engine that gained 75 HP and 10 ft lbs of torque, an 18% power gain.  The LT1 Corvette engine had 40 more HP than My L86.  What made the additional horse power. Can anyone shed some light?  Thanks.

The long block is identical

 

same cam, valvetrain, crank, pistons, everything, part number for part number

 

the differences are

 

intake mani, exhaust mani, tuning, accessory routing

 

difference in power, I believe after seeing nearly every l86 dyno on the internet is....the entire exhaust path of vette, the intake path before the manifold, tuning, drivetrain losses.

 

it doesnt matter much because if you modify any of those things with aftermarket parts, they will far surpass oem equipment on the vette.

Edited by truckguy82
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SRT8dan Enthusiast

SRT8dan

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Posted (edited)

I did some additional research and found a great article on Holly's web site, and you are basically correct.  Almost everything on the two engines are identical with the exception of the intake manifold ( equal runners on the Vette vs longer unequal ones on the L86), a better flowing exhaust on the Vette, and the dry sump on the Vette.  Both engines have the same cam specs at .050 lift (200/207 degrees, .551/.522" lift -1.8 to1 rockers with 116.5 center line), both have sodium filled valves, and both flow 123 lbs/hr on the injectors).  Since horse power is just a mathematical derivative of rpm x torque/5252, the added HP comes with the additional rpms the Vette engine is capable of.

 

It is interesting to note that on the new LT2 Vette engine the cam specs increased +18 degrees on the intake and +4 on the exhaust to get to 495 HP.

Edited by SRT8dan
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lucas287 Enthusiast

lucas287

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@SRT8dan you're spot on. No differences at all between the long block on the LT1 and L86. Even the same throttle body actually. Just comes down to intake manifold and the full exhaust. Sure there are minor differences in tuning, but I'm sure they're very minor. I wish the L86 had a variable intake manifold like the newer Hemi's do - best of both worlds. 

truckguy82 Senior Enthusiast

truckguy82

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Posted
2 hours ago, SRT8dan said:

Since horse power is just a mathematical derivative of rpm x torque/5252, the added HP comes with the additional rpms the Vette engine is capable of.

That is not true

 

The hp plateaus around 5800-6k. Torque starts falling around 4k.

dieselfan1 Senior Enthusiast

dieselfan1

Posted
Posted

I just wish GM ould get off the schitter and offer a supercharger optioned 6.2.
Meanwhile ford and dodge are offering high hp engines .
GM sits and watches.
They might as well shoot their wad now because in ten years they will be not developing any new gas technology. Probably less than than. We might be stuck with what they make now until EV takes over. Sad Sad.

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truckguy82 Senior Enthusiast

truckguy82

Posted
Posted
1 hour ago, dieselfan1 said:

I just wish GM ould get off the schitter and offer a supercharger optioned 6.2.
Meanwhile ford and dodge are offering high hp engines .
GM sits and watches.
They might as well shoot their wad now because in ten years they will be not developing any new gas technology. Probably less than than. We might be stuck with what they make now until EV takes over. Sad Sad.

Sent from my Pixel 3 using Tapatalk
 

Ford is not offering a high hp engine in trucks. That is not released yet and for all we might know gm might slap an lt4 into one around the same time.

SRT8dan Enthusiast

SRT8dan

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I agree. Chev already has a supercharged 6.2 engine. How hard would a detuned version be to put into a Silverado or GMC?  They already have a stout enough rear end and a few tweaks on the tranny would not be all that difficult.

SRT8dan Enthusiast

SRT8dan

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On 2/19/2021 at 2:02 PM, truckguy82 said:

That is not true

 

The hp plateaus around 5800-6k. Torque starts falling around 4k.

Image result for Horse power and torque chart of a 6.2 LT1 Corvette engine

SRT8dan Enthusiast

SRT8dan

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NOT CORRECT! As you can see in the J1349 Dyno chart for a LT1 Corvette engine, even though torque drops off, the horse power continues to increase.  Use the numbers seen on the chart and put them into the equation mentioned in a previous post and see if the numbers work.

SRT8dan Enthusiast

SRT8dan

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Great video explaining where the denominator 5252 is derived. One example I always remember from the olden days was taking a Chev 350 small block and punching it out to a 383 ci.  The additional stroke turned the engine into a torque monster (for the day) which is explained in the video’s first part regarding radius.

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truckguy82 Senior Enthusiast

truckguy82

Posted
Posted (edited)
On 2/20/2021 at 10:26 PM, SRT8dan said:

NOT CORRECT! As you can see in the J1349 Dyno chart for a LT1 Corvette engine, even though torque drops off, the horse power continues to increase.  Use the numbers seen on the chart and put them into the equation mentioned in a previous post and see if the numbers work.

You said the only thing needed for an l86 to make the same power as the lt1 is an increase in rpm.

 

Here’s an l86 dyno, does it look like it’s going to hit 460 by increasing the rpm?

 

 

03616487-2306-46F2-9CA0-C5230A122535.jpeg
 

what do you know, torque starts falling at 4k just like I said

Edited by truckguy82

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