EPA Emissions Regulations Key Factor?

[Rob]

In my continued effort to stir the pot some more here, as read on a GM forums web site, supposedly the current LS7 engine in the Z06 will not pass emissions in another year or two due to stricter emissions regulations coming into play.

As a result, GM had to find an alternative for the Z06 - hence, an engine smaller than 427ci, and supercharged.

What do you think? Fact or fiction?

 

[GerryLP]

It would almost be fiction, except for that time in the early 1970's, so at least there is precedence already established.

It is hard to believe that given the advances in engine and emission controls design, that it would be hard to retrofit the LS7 engine to meet the new requirements.

Is current technology stuck in a plateau?

GerryLP:cool

 

[Rob]

It would almost be fiction, except for that time in the early 1970's, so at least there is precedence already established.

It is hard to believe that given the advances in engine and emission controls design, that it would be hard to retrofit the LS7 engine to meet the new requirements.

Is current technology stuck in a plateau?

GerryLP:cool

Mmmm....but one of the reasons why the ZR-1 met its demise is because the LT5 engine would not pass upcoming stricter emissions regulations without a significant re-engineering that would have cost more money than GM wanted to spend - especially in light of the 300 hp LT1 engine debuting in '92.

 

[Evolution1980]

I would thinkit's a question of physics

What is the physics in the idea that adding additional cylinders or bore or stroke increases emissions? (or the converse)
Or is it just simple math? If one cylinder produces 1% emissions, then eight cylinders would produce 8% emissions?

But if you supercharge something, you are simply increasing the amount of air/fuel being burned. So, (using simple numbers) if you are burning 2x as much air/fuel in four cylinders than in normally aspirated eight, aren't the percentages of emissions the same still?
Or does an efficiency factor come into play here. Such as burning more air/fuel in less cylinders is still more efficient than burning the same amount across more cylinders?

 

[Evolution1980]

the ZR-1 met its demise is because the LT5 engine would not pass upcoming stricter emissions regulations without a significant re-engineering t

Yes, but they would have been re-engineering a technology (DOHC) that they weren't very familiar with in the first place. I'm pretty sure that GM has a firm grasp on how the dinosaur pushrod engine works, as evidenced by the LS7 itself.

 

[Edmond]

Could it be because the SC kicks in at higher speeds and RPM? When they take you for emissions testing here, the max speed you're at is about 60 MPH to simulate expressway driving. I don't know who drives 60 on the e-way. :L

Maybe at lower speeds you use less SC?

 

[Rob]

Yes, but they would have been re-engineering a technology (DOHC) that they weren't very familiar with in the first place. I'm pretty sure that GM has a firm grasp on how the dinosaur pushrod engine works, as evidenced by the LS7 itself.

I don't agree with that at all. The development of the LT5 engine was a joint venture between GM Powertrain and Lotus in Hethel, England.

Lotus was not the sole developer of the LT5. GM Powertrain engineers spent just as much time in Hethel, as Lotus Engineers spent in Detroit.

The LT5/ZR-1 program began to come to fruition around the middle to late 1985. The original design intent was not to go with a DOHC architecture. However due to space restrictions under the hood and between the frame rails of the C4, the DOHC architecture was agreed upon between GM Powertrain and Lotus.

The actual manufacturing of the LT5 was contracted out to Mercury Marine, because Mercury Marine had the experience of manufacturing engines in low volumes, which GM, did not.

Take a wild guess where the Cadillac's Northstar engine came from.....that's right, the LT5.

So I don't agree that DOHC technology was something GM Powertrain was not experienced with.

 

[Evolution1980]

I don't agree with that at all.
Take a wild guess where the Cadillac's Northstar engine came from.....that's right, the LT5.

So I don't agree that DOHC technology was something GM Powertrain was not experienced with.

Good point, I forgot about the Northstar. Now that you mention it, I recall asking/suggesting that the C6 be based around the Northstar engine. (This was before anything else had been specified about the C6.)

One of the points I was trying to make in my original post here is that GM has decades more knowledge with the pushrod engine than a DOHC engine, so their grasp on the pushrod should be much greater and deeper.

 

[Hib Halverson]

Mmmm....but one of the reasons why the ZR-1 met its demise is because the LT5 engine would not pass upcoming stricter emissions regulations without a significant re-engineering that would have cost more money than GM wanted to spend - especially in light of the 300 hp LT1 engine debuting in '92.

That's pure bull based on General Motors spin.

In fact, the 475hp, 1995-96 LT5 which would have to have been compliant with the second generation on-board diagnostics (OBDII) requirement for MY96 was already under development with several prototypes of the engine in testing when the LT5 program was killed in 1991.

There was no problem with the engine meeting emissions for 96.

The problem was the cost of upgrading the LT5's engine computer to give it the extra diagnostic abilities required by OBD II. GM decided not to spend the estimated $1,000,000s to do that but really--had politics inside General Motors Powertrain Division not already damped any further enthusiasm for the LT5, they'd have probably spent the money.

More GM spin is the problem of the 92 LT1 being too close in performance. Yeah, the gap would have closed for 1992. But in 93 it widened and, had the 3rd gen LT5 appeared in MY95, it would have further widened.

 

[Rob]

That's pure bull based on General Motors spin.

In fact, the 475hp, 1995-96 LT5 which would have to have been compliant with the second generation on-board diagnostics (OBDII) requirement for MY96 was already under development with several prototypes of the engine in testing when the LT5 program was killed in 1991.

There was no problem with the engine meeting emissions for 96.

The problem was the cost of upgrading the LT5's engine computer to give it the extra diagnostic abilities required by OBD II. GM decided not to spend the estimated $1,000,000s to do that but really--had politics inside General Motors Powertrain Division not already damped any further enthusiasm for the LT5, they'd have probably spent the money.

More GM spin is the problem of the 92 LT1 being too close in performance. Yeah, the gap would have closed for 1992. But in 93 it widened and, had the 3rd gen LT5 appeared in MY95, it would have further widened.

Interesting. I didn't know any of that. I stand corrected.

 

[*89x2*]

.

As a result, GM had to find an alternative for the Z06 - hence, an engine smaller than 427ci, and supercharged.

What do you think? Fact or fiction?

Callaway Cars' SC560 package w/ their LS2 based Corvettes is 50 state legal - with over 560 hp now, and more in the (near) future, there may be some benefits to forced induction on a smaller displacement engine :cool


The 427 badge has / had a nice ring to it - but other (better) technology is out there :cool

 

[Aurora40]

I may be wrong, but I don't believe the requirement to meet 50-state emissions legality on an existing car is nearly as strict as the federal and state requirements to sell a car as "new".

As Hib mentioned, OBD-II was more about more sensors and computing than really about tightening any emissions. It was about the car being able to monitor emissions degredation on it's own. The big hurdle for most engines was probably time and cost.

Just since it was mentioned, the Northstar didn't appear until 1992 on a '93 MY Cadillac Allante. The LT5 development would have occurred way before this. However, GM engineers would have had experience with the Oldsmobile Quad-4 which debuted in the 1987 MY. Though I believe the powertrain groups were separate for CPC and BOC (Buick, Olds, Cadillac).

I wouldn't say supercharging is "better" technology. It's different technology. I'm sure a blower on a smaller displacement (but same physical size) motor would result in a heavier car with lower fuel economy numbers. It might be the way the 'vette goes, though. Ford went that way with the Cobra, and I thought the result was absurd. A 400hp Mustang that weighed as much as my Aurora does. The SC and related iron block requirement resulted in a Mustang that weighed almost 2 tons. The GT500 has the same problem. Whether it's the way to go on the 'vette, I guess we'll have to see. No doubt 650hp makes a good argument, though.

 

[*89x2*]

Bob, you are correct, aftermarket and small volume manufacturers do not have to meet quite as stringent run-arounds to get a car certified for the road.

Point is though, it did go through a process and IS certified.

Diesel requierments are getting tougher this year and I am sure the "greenies" would love to see all internal combustion engines pollute less - nevermind the fact they have never been cleaner...

In essance, the cost to get the car to the emissions standards )whether through cleaner tailpipe numbers or through an OBD II arrangment) did kill off the LT5. The cost to do this killed the LT5 - isn't OBD II about emissions :confused

 

[Edmond]

How many years of lead time were manufacturers given to comply with OBDII standards? From my recollection, Toyota started doing hybrid type things of OBDII systems in their 1994 vehicles, two years before it was mandated for 1996 vehicles.

 

[Aurora40]

In essance, the cost to get the car to the emissions standards )whether through cleaner tailpipe numbers or through an OBD II arrangment) did kill off the LT5. The cost to do this killed the LT5 - isn't OBD II about emissions :confused

OBD-II was about emissions monitoring, not really emissions. It was about monitoring the emissions equipment to ensure it operates properly over time. This is why now you can have your OBD-II car emissions inspected by them just hooking up to the computer and ensuring all the monitoring tests have passed and no codes are present instead of them sniffing the tailpipe.

I'm not an expert, but I don't believe there were any tailpipe emission tightenings with the OBD-II requirement for 1996 MY cars.

 

[Evolution1980]

OBD-II was about emissions monitoring, not really emissions. It was about monitoring the emissions equipment to ensure it operates properly over time. This is why now you can have your OBD-II car emissions inspected by them just hooking up to the computer and ensuring all the monitoring tests have passed and no codes are present instead of them sniffing the tailpipe.

And this actually can pose a problem, at least for the consumer. My last OBD-II car had a bad coolant sensor or something. Whatever it was, it was causing the computer to read incorrect codes and light up my "Check Engine" light. I knew this was going to be a problem when I went for my e-check. In Ohio, they won't even hook up to your car if the MIL is lit. They'll tell you to come back when it's no longer lit up.

I took my scanner to the testing station with me. Right before I pulled into the station's lot, I hooked up my scanner and cleared all my codes to get rid of the "Check Engine" light. I pulled into the station and voila! it wasn't giving any codes. (And of course, I had the scanner covered under a blanket in the back seat... :L)
One might say that I was cheating and that's illegal. However, I still had to do the sniffer test because the old-timer administering the test couldn't bend in such a way to get a secure connection to my computer. So they ordered the sniffer test in place of the computer link-up. As I knew I would, my car passed with flying colors!

Granted, my example is an isolated one, but it's proof that it does happen. That being: simply monitoring the OBD-II systems isn't 100% factual, as it can be manipulated to give either positive or negative results.
In some cases, clearing the codes will pass a car that shouldn't pass. And in my case, clearing the codes allowed me to pass in a situation where they normally would have incorrectly failed me.

(Sorry for the slight tangent. )

 

[motorman]

according to GM the LS series engines were designed to meet the emission std for 20 years. that is unless the libs now in charge in washington change them.

 

[grapeknutz]

One must remember that 5 years in engine development time is a huge deal. back when the ZR1 engine was in production it was using OBD1 engine management, now we are into OBD2 and near OBD3 generation with means the computers can manage a heck of alot more engine functions, thus emission dutys. Also technolgy marches on in dealing with catalysts and fuel refinements. Although GM may have been able to make the ZR1 engine live on, I think the cost of the engine may have been the factor the ended it's usefullness. Also one can't discount GM's bean counters as a factor in all of GM decisions in what engine live or die.
But I maybe wrong also.

 

[*89x2*]

without opening a can of worms...

...and near OBD3 generation with means the computers can manage a heck of alot more engine functions,

...let's hope OBD III is never mandated, please hope. :ugh

 

[c4c5specialist]

OBD2, 3 or emissions compliance, NOTHING!!!!

HI there,
Emissions are constantly variable, however, to think that any LT5, LT1 or any engine would NOT maintain guidelines, is silly.
Emissions have everything to do with catalytic converter location, combustion chamber EFFICIENCY and burn characteristics.
Generation 3 smallblocks, with their tumble burn rates and the changes deliver superior combustion of fuel under all conditions.
Generation 4 is even better.
LT5, with 4 valves per cylinder, centrally located spark plug and other factors, burn very well.
Then, the evolution of the catalytic converter as its become more efficient, and location has moved more and more toward the engine to keep it hotter and working better.
Higher pressure fuel systems atomize fuel better, giving better burning.
Higher compression, combined with correct camshaft overlap makes all emissions gases much lower, so the converters work less, but are also more effective on the gases that ARE left over.
Fact is, OBD1, OBD2 and soon OBD3 are MONITORING SYSTEM REQUIRED BY THE EPA. This is so everyone, private garages and dealerships can work on them, while maintaining a standard that EMISSIONS CAN BE MONITORED BY.
This has nothing to do with anything else.
LAN PROTOCOL is a faster way of running systems between computers in cars/trucks and it makes the ABS/TCS and engine management work more SEAMLESS, but that is all.
If you can geta 64 Corvette, 327 with converters and aluminum heads to meet 1992 emissions standards, imagine how far C6 can go? They are ALREADY LOW EMISSIONS VEHICLES CERTIFIED.
And the answer to the question that Rob posted,,,,,
FICTION

Allthebest,