[ULTRAZLS1]

Originally Posted by SpeedIsLife

I think the design is limited due to the bore spacing to allow it to be built on existing lines at the Romeo plant

Bore spacing yes. That is one issue

[LesserO2Evils]

Originally Posted by Blackdevil77

One thing I'm slightly confused on, why do I keep hearing the LT1 referred to as a truck engine? Did I miss something?

Noob is of this mindset(like the Pony boys) that Pushrod engines are old, dont make power, and are for "pickups". He was blasted pretty hard for this the other day, and thoroughly educated, but it appears to have fallen on deaf ears.

[Bhobbs]

If it had an engine like the AMG 6.2, it wouldn't start in the mid 30s.

[doc7000]

Originally Posted by SuperSound

There is, it's called Fuel Efficiency and Emissions. The larger the displacement the more emissions the engine outputs and generally lower FE. You can develop technologies (like VVT, DOD, DI) to improve this of course, but OHC designs benefit from the same tech too. OHC engines are physically bigger and heavier than a similar displacement OHV engine, so engineers have to pick one over the other for most applications. OHV are cheaper to produce too. In the end, the difference can be summed up as:

Cheaper, smaller size, less weight, worse FE/Emissions - OHV
More expensive, lower displacement, better FE/Emissions - OHC

This is definitely a simplification, but I think represents the main points. In Europe FE/Emissions has been a bigger driving force for engine development than in the US. In the US, people really didn't focus on FE until gas hit $4 a gallon. The price in Europe has been higher than that for decades. So OHV died out quicker there than in the US, because it wasn't as big a priority, particularly in the V8 market for trucks and performance cars. Couple that with taxes on displacement in Europe and you have your answer as to why all you see is OHC engines.

The fuel economy and emissions picture is much more complicated then that, if you have an engine that is tuned for high top end in a DOHC format then fuel economy and emissions is going to suffer. one intake and one exhaust valve (which is also done with SOHC and DOHC engines) is better for emissions and if I remember cold start emissions. This was one of the reason that Mercedes had went from a DOHC 4 valve head layout to a SOHC 3 valve engine some years ago (and the automotive press bitched).

5 valve heads flow better then 4 valve heads however the 5 valve head was ditched (largely because it put huge limitations on head design and was too big of a compromise).

The Duramax diesel is an example of a OHV 32 valve V-8 engine, not a lot of companies builds those either. Also there was plans for a 3 valve OHV V-6 engine though the OHV V-6 was phased out. They also looked at two cams in block one for intake and the other for exhaust but really all power, fuel economy, and emission goals were met without the need for it.

[doc7000]

Originally Posted by Bhobbs

If it had an engine like the AMG 6.2, it wouldn't start in the mid 30s.

It would also be part of the class action lawsuit against Mercedes due to a defect with that engine.....

[SuperSound]

Originally Posted by doc7000

The fuel economy and emissions picture is much more complicated then that, if you have an engine that is tuned for high top end in a DOHC format then fuel economy and emissions is going to suffer. one intake and one exhaust valve (which is also done with SOHC and DOHC engines) is better for emissions and if I remember cold start emissions. This was one of the reason that Mercedes had went from a DOHC 4 valve head layout to a SOHC 3 valve engine some years ago (and the automotive press bitched).

5 valve heads flow better then 4 valve heads however the 5 valve head was ditched (largely because it put huge limitations on head design and was too big of a compromise).

The Duramax diesel is an example of a OHV 32 valve V-8 engine, not a lot of companies builds those either. Also there was plans for a 3 valve OHV V-6 engine though the OHV V-6 was phased out. They also looked at two cams in block one for intake and the other for exhaust but really all power, fuel economy, and emission goals were met without the need for it.

Yep it was a simplistic answer for what is a very complex process of choosing what works best in an application while taking into account cost/profit margins and company goals.

Sent from my SAMSUNG-SM-N900A using Tapatalk

[13vertss]

What is the norm for drivetrain loss? The LT1 shows less then a 10% loss from engine to wheels. That's awesome.

[ULTRAZLS1]

Legend has it GM had an ohc and ls1 4th gen testing side by side in the mid 90s. Everyone that was on the project preferred the ls1. It was a choice. It has nothing to do with being behind or not " high tech" enough. Ford and GM chose different paths.

As far as drivetrain loss... That has nothing to do with the lt1. It is a reflection of drivetrain efficiency. Tranny, rear end, driveshafts , wheels tires etc

As far as a norm that's hard to pin down... Different brands don't use all the same drivetrain parts and every dyno is different.

[13vertss]

I know it has nothing to do with the LT1 in general, just impressed with so little loss to the wheels. These newer cars are really getting efficient. Just 10 years ago, the norm was 15% loss with a stick. Now it's less then 10%?

[Iroc_Z28]

Originally Posted by ULTRAZLS1

Legend has it GM had an ohc and ls1 4th gen testing side by side in the mid 90s. Everyone that was on the project preferred the ls1. It was a choice. It has nothing to do with being behind or not " high tech" enough. Ford and GM chose different paths.

LT5 gen II was being developed around the same time as the LS1 for the c5 vette, i've heard that many components of the LT5 project went into the ls1...The way i see it, if only outright HP was taken into consideration, the corvette would have been DOHC v8 powered from c5 and on, even the base models... rumor has it that the base c5 would have been 450 hp, z06 600 hp and zr1 700 hp, all powered by DOHC N/A v8.... of course this would have driven costs wayyy up, and packaging would have been quite the challenge....

[ULTRAZLS1]

Originally Posted by 13vertss/r's

I know it has nothing to do with the LT1 in general, just impressed with so little loss to the wheels. These newer cars are really getting efficient. Just 10 years ago, the norm was 15% loss with a stick. Now it's less then 10%?

It is lower that's for sure. A lot of vehicles look to be in the area of 10% I'd say. Lot of variables though.

[ilirg]

I think we can all agree, Noob should buy a Mustang or a Mercedes AMG.

[doc7000]

Originally Posted by Iroc_Z28

LT5 gen II was being developed around the same time as the LS1 for the c5 vette, i've heard that many components of the LT5 project went into the ls1...The way i see it, if only outright HP was taken into consideration, the corvette would have been DOHC v8 powered from c5 and on, even the base models... rumor has it that the base c5 would have been 450 hp, z06 600 hp and zr1 700 hp, all powered by DOHC N/A v8.... of course this would have driven costs wayyy up, and packaging would have been quite the challenge....

Having read plenty of articles on both the LT5 and LS1 engine, there is no basis at all to that rumor.......

When the LS1 engine was being developed they had engines early on running at over 400BHP. Not only could the 5.7L LS1 engine match the LT5 engine in horsepower the LT5 engine needed a lot of complexity in order to produce good low and mid range.

The LT5 engine is in no way shape or form related to the generation II small block chevy and was at first planned to have a greater then 4.400 inch bore center spacing making 400BHP. For marketing reasons they forced Lotus to use the 4.400 inch bore center spacing, as a result Lotus could only deliver 375BHP from the engine.

What badly hurt the LT5 engine was the LT1 engine, the ZR1 Corvette was nearly double the price of the LT1 Corvette without offering nearly twice the performance. The LS1 started life off as a further development of the generation II SBC, however that was scratched in favor of a ground up design. However some of the development work ended up going into the LT1 and later LT4 engine. It is also documented that the LT4 engine produced wildly varied amount of horsepower/torque (source Corvette action center). If you had an LT4 Corvette it made anywhere from 330BHP all the way to 384BHP from the factory for some odd reason.

These developments, the fact that they were able to produce LT5 horsepower and torque and broadness without the added cost and complexity really killed the LT5 engines future.

The other benefit of the LS1 engine over the LT5 engine was the smaller size and lighter weight of the LS1 engine over the LT5. This allowed the use of a lower hood line and reduced overall vehicle mass. Also at the time that the C5 was entering production it was believed that there was no market for higher end Corvette due to the poor volume of the ZR1 Corvette. The FRC C5 was actually planned to have cloth manual seats, roll up windows, etc.... and was planned to be a bit cheaper and lighter then it ended up being. Luxury features were thrown back into the car to get higher transaction prices for the car. Shortly after the launch of the C5 they found that there might actually be a market for a higher up Corvette. With the slow selling FRC being the lightest iteration and stiffest of the C5 became the basis for the 2001 Z06 Corvette making 385BHP in 2001 and 405BHP in 2002.

As things stood I don't even think that the LT5 engine can fit in the engine bay of the C5 Corvette.....

[Autonaut]

Originally Posted by Noob

hm, I would rather have a 6.2ltr. DOHC with 84.6hp/ltr. in that 2016 Camaro instead of "only" 74,2hp/ltr. due to old 2valves/1cam design.
My brothers AMG C63 is that engine which cranks out 525hp in his 2009 Mercedes. It revs 7200rpm and was "engine of the year" 2 times.
It weighs 439lbs.....i read.
http://mbworld.org/forums/w211-amg/2...ne-weight.html

Perhaps Chevy know the selling numbers of V8´s will fall as tax and gas prices increase. So they decide not to spend mch more money in further developing of a given and surely proofed design. A direct fuel injection is a small intervention adn cyl..deactivation helps saving fuel on an old design which normally drink 1-2ltr more per 100km compared to a newer design with less capacity but equal hp.

You again!

Do you never learn? Why do you insist on being stupid? All info is at hand yet you keep spouting wrong info.

Both designs are old you idiot. None of them are obsolete though. Not at this moment. And hp/l is a ridiculous measure by itself. Packaging and engine weight. Simplicity. Cost of production. Center of gravity. Emmisions. And many other variables come into play.

Come back when you turn 18. Then maybe you will have picked up a thing or two..