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#1 |
Join Date: Aug 2005
Location: Fishers, IN
Posts: 809
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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
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Todd ____________________________________ *** our email address has changed! info@pepmeierengines.com pepmeierengines.com Friend us on Facebook too: www.facebook.com/profile.php?id=100011443683384 Pepmeier Engine Development Last edited by tpepmeie; 10-26-2021 at 03:46 PM. |
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#2 |
![]() Join Date: Feb 2011
Location: Clayton, North Carolina
Posts: 1,133
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Patience Todd. Not sure it?s adaptable to a front engine layout?
Sent from my iPhone using ZR-1 Net Registry
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Lou[COLOR="Red"][B][SIZE="4"][/SIZE][/B][/COLOR] |
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#3 |
Join Date: Aug 2005
Location: Fishers, IN
Posts: 809
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Well, the bore spacing is the same.... maybe we could retrofit the heads and intake.... LOL
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Todd ____________________________________ *** our email address has changed! info@pepmeierengines.com pepmeierengines.com Friend us on Facebook too: www.facebook.com/profile.php?id=100011443683384 Pepmeier Engine Development |
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#4 |
Join Date: Aug 2005
Location: Fishers, IN
Posts: 809
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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. Sent from my iPhone using ZR-1 Net Registry
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Todd ____________________________________ *** our email address has changed! info@pepmeierengines.com pepmeierengines.com Friend us on Facebook too: www.facebook.com/profile.php?id=100011443683384 Pepmeier Engine Development |
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#5 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,696
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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.
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#6 |
![]() Join Date: Nov 2016
Location: New Brunswick
Posts: 952
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If it only came with a manual.....
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#7 |
![]() Join Date: May 2010
Location: Japan
Posts: 3,567
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![]() 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. Sent from my iPhone using ZR-1 Net Registry
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#8 | |
![]() Join Date: Nov 2016
Location: New Brunswick
Posts: 952
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1990 ZR-1 # 996 "All Corvettes are red. The rest are mistakes." - John Heinricy |
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#9 |
Join Date: Sep 2018
Location: Florida
Posts: 304
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#10 | |
![]() Join Date: May 2010
Location: Japan
Posts: 3,567
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100% [emoji1360]🤙🏼 Sent from my iPhone using ZR-1 Net Registry
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Craig "ZR-1 NO KA 'OI" "ZR-1 ICHIBAN" 1995 #228 Black/Black with Dunn Heads ZR-1 owner since September 2003 ZR-1 Net Registry Founding Member #0074 NCM Lifetime Member #2048 ![]() |
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