Documents Indicate LT5 = 6.2L NA DOHC V8 --- Bottom of Page 5
12-23-2016, 03:50 PM
#41
Safety Car
12-23-2016, 04:16 PM
#43
1) Shouldn't need a 6.2L displacement for a DOHC high-performance engine. Something a liter less should be plenty to work with.
2) If the Corvette is to be a high-tech Sportscar, it's powerplant should reflect that (smaller, lighter, more efficient).
3) I suspect GM Marketing insisted on 6.2L in order to help win this obvious future argument...
CORVETTE BUYERS: "It doesn't have PUSHRODS!!!!"
GM: "But the engine is the same size!"
4) Last, and not least -- the SOUND! Larger displacement creates a particular basso or lower tone, which is not my 1st choice in exhaust notes.
As far as current American V8s go, the LTs rank at the bottom in terms of aural joy (IMO).
The LT engines sound WAY too much like a 40 year old Chevy Pick-up sans mufflers...even the LSA in my old CTS-V sounded a LOT better (menacing).
Of course, the pleasure one derives from any particular sound source is completely subjective and YMMV.
12-23-2016, 05:40 PM
#44
Le Mans Master
12-23-2016, 06:27 PM
#47
I don't think you can hear what I'm saying. I'm not referring to reasoning of why GM choose a particular valve train design or valve events.
12-23-2016, 06:29 PM
#48
Le Mans Master
Like he said, and!
The Z will net more power around the track due to the relative power increase under this curve being engaged more without PTM on. The absolute peak number will be irrelavent. Less good or great power wins! Even the Viper platform will be weaker even with its larger peak numbers!
Dynamic!
Dynamic!
Last edited by johnglenntwo; 12-23-2016 at 06:35 PM.
12-23-2016, 06:32 PM
#49
The 5.7L LT5 in the C4 ZR-1 had more low-end torque than the 5.7L L98 or LT1, my C4 ZR-1 will easily pull 6th gear from 25 MPH/~500 RPM. You're confusing the low torque output of the typical small displacement DOHC engine with the reality of a large displacement DOHC engine, the latter is fantastic. Displacement and compression ratio are the two main factors which determine torque, DOHC engines can run more compression due to the superior combustion chamber design compared to OHV engine combustion chambers. DOHC engines can run less cam duration due to superior valve "curtain area", intake valve closing point determines low RPM torque and being able to vary intake and exhaust cams independently increases low RPM torque for the DOHC engine.
12-23-2016, 06:38 PM
#50
After putting headers (shorties), a Bassani X-Pipe, and Borla exhaust, it became the best sounding domestic street car I have ever heard.
Nasty, vicious, snarly...and it could "sing" at high RPMs.
Also had a 2005 XLR with a 4.6L DOHC.
Smooth purring sound, which could howl under duress and was perfect for the car's mission as a luxo-cruiser.
Naturally aspirated, look for the new LT5 to make 620-650 HP at the peak. More importantly, the new LT5 will have a very broad power range spanning at least 2000 RPM where the HP curve is almost flat because HP doesn't vary more than 20 HP from peak HP. Compare that to the LT4 HP curve which is a straight line up to 650 HP and then you hit red line...the average HP from the LT5 will kick the poop out of the LT4 and not have overheating issues. The above is just a few of the reasons behind going to DOHC.
Last edited by sunsalem; 12-23-2016 at 06:38 PM.
12-23-2016, 06:49 PM
#52
OTOH, who doesn't love the sound of an engine at high RPM?
Another possibility for the DOHC is to tame some of the monstrous torque of the LTs (particularly the LT4) by REQUIRING the driver to push hard on the pedal.
As you know, many have complained about having difficulties managing it off-track in a street situation.
With very little pedal, the LTs can unleash a lot of power.
Just a thought...
12-23-2016, 06:56 PM
#55
Safety Car
Same question for volume displacement and complexity. Heck you can even ask the same question for engine height since the TVS sits on the block.
12-23-2016, 07:00 PM
#56
Le Mans Master
None!
The evolution!
Last edited by johnglenntwo; 12-23-2016 at 07:01 PM.
12-23-2016, 07:07 PM
#57
Le Mans Master
GM has budgeted money for new V8 line in Towanda New York.
So I guess we get a new engine.
z51vett
Doug
So I guess we get a new engine.
z51vett
Doug
12-23-2016, 07:12 PM
#58
Safety Car
The block will be the same, the heads will be larger to accommodate the cams. Having said that, Mercedes Benz has a 6.2L DOHC engine that weighs the same as the LS3 6.2L engine which weighs less than the C7 LT1...look for engine weight to be very close to the LT1 and much less than the LT4.
I agree, don't look for this engine to be standard equipment...I don't think anybody here is expecting that though.
I agree, don't look for this engine to be standard equipment...I don't think anybody here is expecting that though.
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G fix needy (12-23-2016)
12-23-2016, 07:20 PM
#59
Don't know about weight...we will have to wait to see more specs from GM.
As far complexity goes, I don't think GM engineers will break their noodle putting one together since other manufacturers haven't.
Modern engines are pretty bullet-proof these days.
If they build one, I'm sure it will be just fine in terms of reliability.
12-23-2016, 07:40 PM
#60
Safety Car
Accessories (starter, alternator, harmonic balancer, etc), headers, intake manifold, and in some cases flywheel and other clutch related parts are not included. Heads are of course.
Last edited by SBC_and_a_stick; 12-23-2016 at 07:41 PM.