2009 Corvette ZR1 LS9 Engine

[culver]

An interesting comment... Total speculation even though you had the graphs... Look at the Wankel graph... this is a LeMans winning 4 rotor engine yet it is as efficient as the LS7. the old Jeep 230ci I6 (Jeep Tornado engine aka 6-230) is more efficient even though it is from 1962 and had SOHC with only 6 lobes (I will let you guess how that worked)... And I really like that you can state that of course a smaller efficient engine is an economy engine and should be more efficient than the LS7... (that would imply that the LS7 is not overly efficient). There is nothing wrong with speculation as long as it is logical.

You know, I guess I am missing something here….
Where is the chart that shows Ferrari BSFC vs the LS7? After all, you said the Ferrari was better. It’s nice that we can walk down and look at charts that aren’t related but how about some charts that are?

And remember, I never said the LS7 was efficient. I am saying that you haven’t show that it would be less efficient than the Ferrari 430’s motor. All I’m asking is that you back what you say

BTW, you didn’t say if there were circumstances that would make those charts non-comparable. Kind of like how chassis dyno numbers aren’t always comparable.

I would think that the LS7 is more efficient than the LS2 and LS3... but then that is only speculation based on a few factors... Maybe you have some BSFC data to back your speculation...?

I certainly don’t. I didn’t say I did. However, I would suspect that the lesser motors are more efficient partly because GM does care about CAFÉ numbers and those lesser variants are used in more cars. Also, when doing the LS7 GM said they basically couldn’t get any more power out of the small block while maintaining emissions and not using FI. That means they likely would always trade efficiency for power. With the lesser motors they might have actually had the opportunity to trade otherwise. Now I understand that isn’t a technical justification but it’s my first blush. Then again, you haven’t given any justification in this case and your Ferrari vs LS7 justification thus far has been crap.

I have put forth alot of factors that you have yet to argue... Neither of us have the necessary data to make a definitive conclusion so the best we can do is speculate. But I said that like 10-15 posts ago...

No, you have thrown up a smoke screen of pseudo factors. You have not put together a complete and logical explanation and you certainly haven’t presented the data.

I am not going to spoon-feed you the data. This is an internet forum and as such I don't feel like spending the time to do that properly. If you don't want to read the graphs fine, but don't make comments until after you have looked at them.

The problem is the graphs don’t provide an explanation. Sure they provide graphs that show you can find some motor info but they don’t prove your point. They don’t prove that the Ferrari motor is more efficient than the LS7. That was a claim that you made without proof. How can we trust someone who makes such claims without proof?

You won't be able to... Not without misreading the graphs. If you actually said that and showed how you came to that conclusion (maybe highlighting the areas you are talking about) then we could have a discussion...
I’m only “misreading” because I’m not accepting the line of BS you are feeding.

Only at high BMEP (ie high throttle open angle). At lower BMEP the 4VPC data is more efficient.

Wow, maybe you can read a graph.

Wow you finally found what I had been stating several hundred posts ago... Only you got it half right... The transmission ratios are not designed to allow a large speed range over a short rev range (only 6th and possibly 5th is) the spread of the gear ratios is the key (ie. the first 4 ratios cover roughly the same total ratio as the 6 ratios in the ferrari).

I never disagreed with this point. However, I also said it was a method well suited the the engine in question. You just seem to think it’s cheating or something.

I never did call it otherwise. There are many factors that would imply that the Ferrari engine is more efficient that is what I have always said. If you want to prove me wrong then you are going to have to discuss the factors I mentioned, bring up new factors, or show BSFC data. If you don't want to do any of that then stop posting...

Um, you sure did. You didn’t say you were speculating and I haven’t seen this Ferrari data. Where’s the beef? Don’t cry when I ask for the facts.

Why is it that you confortably speculate yourself but jump on me for speculating? It is simply ridiculous that you jump on me because you think I sounded like I had proof when I don't... Think about that for awhile... Why didn't you just say "Do you have BSFC to prove that definitively?" I would have answered "No I do not but there are several factors that would imply greater efficiency" to which you could have discussed the factors or just said fine... Instead you chose to waste time and space...

Because I admit when I am speculating and I normally say on what basis and accept that I might not be right or that extenuating circumstances may make a generalization untrue in a specific case. You simply assume that you are right but show no proof. I would certainly say the Ferrari is an extenuating circumstance case. More so given that it not only gets lower EPA numbers, but lower mileage numbers in real tests as well.

Your Loss... Not mine...

The only thing I’ve lost is respect for you.

Hey, you forgot to answer a few questions… what do you do and what education do you have in this field?

One more thing, please don’t be so crabby when people ask you to prove what you say.

[culver]

One more thing, I'm done responding to the Ferrari vs LS7 efficiency stuff. It's clear you don't have the info to back your stance. Come back when you have the Ferrari data. Hell, come back when you have any Ferrari data.

However, I do still want to know why you think the two dyno plots show the Corvette motor as soo much less flat and what you do and where you were educated.

[hightower99]

Well let's look at this. I see the Ferrari graph which starts at 2500 RPM showing an 18% difference between min and peak torque values. At the same time the LS7 graph shows 19% if we go from 2000 to peak. I'm not using it down to 1000. But what if we start at the same 2500 RPM? How often would you be below 2500 when driving a Corvette in the hills, well when I did it, very rarely. Well then we get 16% difference between peak and min.

HAHAHAHAHAHA!

You are really hilarious!

The graph shows roughly 360Nm torque at 2500RPM... (266lb/ft.)
Peak at 465Nm at 5250RPM... (343lb/ft.) which is a 22.45% difference...

But more importantly it is 28lb/ft. per 1kRPM

The corvette shows 367lb/ft. at 2500RPM and peaks at 439lb/ft. at 4800RPM now whereas that is only a 16.4% difference it happens at a rate of 31lb/ft per 1kRPM... That's why the Ferrari torque curve is flatter.

So why are you so critical of the torque curve? You're claim that it's not as flat is at best a half truth because the difference is VERY small or non-existant depending on how you want to slice the apples.

I am not critical at all. Mathmatically the Ferrari has a flatter torque curve that's just how it is.

[hightower99]

Just because you don’t understand is no reason to get pissed when I show that you aren’t as smart as you think.

What did I misunderstand and since when did = pissed? isn't = pissed

When you don’t present the full set of facts you are BSing people. You throw up a bunch of stuff and act like you are so much smarter than the rest and say “I’ve proven it!”. The problem is most of the time you haven’t.

It's funny how you think you know how I think... Anyways No I don't put info up and say "there I proved it" I put it up and expect well-mannered discussion.

Again, not my job.

SO if I held up a red card you want me to say "this is a red card"... wow... lame...

I would half agree. It is the base MB engine in the US. It is also a FI motor which you should have disclosed. FI motors can be more efficient than non-FI motors (though this is not always the case). So are you saying a FI I4 motor would be representative of the Ferrari’s efficiency?

SHOCK!!!! you actually read the link???

....Progress

It's a shame that you totally missed the point and reason why I posted those graphs. It was not in any way related to the Ferrari vs. LS7 arguement, I put them up purely to show that indeed the LS7 is not an amazingly efficient engine.

BTW: It is a supercharged engine which means that the FI system cannot increase the thermal efficiency to the system (just thought I would disclose that, as it is relevant ).

BTW, only you have it in your head that the Ferrari motor has better BSFC than the LS7 motor. The charts and theories you have presented are either questionable or do not support the theory.

Well you could have fooled me because as of yet I haven't seen any speculation or info from you that would suggest the Ferrari is less efficient (you haven't even disputed the factors I mentioned).

But I have questioned the factors you used to make the claim. Instead of coming up with a real answer you insulted me and got pissed.

Did you? well I can't see where you did... Maybe you would be so kind as to tell me what post number? Possibly make an easy to read list of the questions?

I’ve looked at all of them. The thing is I’m not questioning that the LS7 isn’t not going to be any Mecca of engine efficiency. It’s a performance engine (even if you don’t think so). However, I am questioning your BS notion that the Ferrari engine is more efficient because you think so. It might be more efficient but I would never make the claim without real data. I guess you don’t worry about having real data before making claims.

So let me get this straight... You know that the LS7 is not overly efficient (apparently based solely on the fact it is a performance engine) yet it is considered BS to say that the Ferrari is quite possibly more thermally efficient?

As for the conversion factor BS, yes I can convert the info. I said how to do it. However, when I was typing that post I was not in a place to go grab my conversion table. You should have done that so people, other that us who can convert numbers, people who don’t know as much as we, could look at the numbers directly.

Ahh so thats what back-peddaling is! thanks for the excellent text book example You could have used google and got the conversion number in about 30 seconds. You also still completely dodge the fact that 3 out of the 4 graphs were converted...

Do you say engine A is more powerful than B while showing Hp for one and kW for the other? I would hope you would convert both to the same units before claiming A is better than B. I’m asking you do the same thing for the BSFC data.

Quick! which is more powerfull: 300HP or 300kW? I guess I just give you too much credit, assuming you can do such advanced math as converting g/kWh to lbs/HP/h and kW to HP...

No I wouldn’t trust you. I’ve seen you draw bad conclusions that support your notions rather than the facts.

hahaha... you definately lacking in the perception area. Even though I marked that as a rhetorical question you still answered. Not too bright


PS. I hope the abundance of smileys shows that I am not pissed...

[culver]

HAHAHAHAHAHA!

You are really hilarious!

The graph shows roughly 360Nm torque at 2500RPM... (266lb/ft.)
Peak at 465Nm at 5250RPM... (343lb/ft.) which is a 22.45% difference...

But more importantly it is 28lb/ft. per 1kRPM

The corvette shows 367lb/ft. at 2500RPM and peaks at 439lb/ft. at 4800RPM now whereas that is only a 16.4% difference it happens at a rate of 31lb/ft per 1kRPM... That's why the Ferrari torque curve is flatter.

I am not critical at all. Mathmatically the Ferrari has a flatter torque curve that's just how it is.

OK, it shows slightly lower than the 380Nm I initially thought it showed. I guess I was being generous. Well I'm willing to cede that point to you. So now it actually shows a larger percent difference between min and max torque over the range.

You seem to agree with my 16% number. So how is 22% less than 16%? Which is less change, 16% or 22%?

You seem to be backing your view with non-scaled numbers. Well lets see my lawn mower makes less than 28lb*ft (not lb/ft) at peak power. Thus including when it is not running at 0 rpm it must have a flatter torque curve than the Ferrari! Way to go Briggs and Stratton!

"Ha Ha! My lawnmower has a flatter torque curve than your Ferrari!"*
*According to HT

Do you see why we need to use the percentages? And even you admit as a percent of peak power the LS7 curve was flatter (based on the graphs you provided).

Again, how can we trust what you say if you are twisting the data this much? You presented these two graphs to support your claim. You didn't actually analyze the data for us, you just said the graphs proved it. However when I look at the graphs I see the LS7 showing a smaller % change in torque. You are trying to claim the Ferrari is flatter based on the absolute numbers but that doesn't work because using that logic my lawnmower is flatter than both as it doesn't make even 28lbft of torque!!!!

Oh, you also were pissing and moaning about me not doing a unit conversion (when I was not in a place to do it at the time) yet you don't even have your units of torque correct.

What are you (not) thinking?!

Hey, how come you are ducking the question about what you do and what your education is?

[culver]

Quick! which is more powerfull: 300HP or 300kW? I guess I just give you too much credit, assuming you can do such advanced math as converting g/kWh to lbs/HP/h and kW to HP...

Quick, which is more powerful, 255.4hp or 187.3kW?
It’s easy when I say which is bigger, 10kg or 10lb(mass). It’s harder when I say which is bigger, 32.41kg or 72.34lb? How about 364 lb*ft/min vs 1.875 calorie/second. Many you should have seen the SI vs English units when talking about enthalpy and entropy!
Funny how your example falls apart with such an easy counter example. Do you now see why you should present all the information in the same units?

[hightower99]

You know, I guess I am missing something here….
Where is the chart that shows Ferrari BSFC vs the LS7? After all, you said the Ferrari was better. It’s nice that we can walk down and look at charts that aren’t related but how about some charts that are?

You seem to be confused. Those charts are there to show that the LS7 is not an overly efficient engine, nothing else.

And remember, I never said the LS7 was efficient. I am saying that you haven’t show that it would be less efficient than the Ferrari 430’s motor. All I’m asking is that you back what you say

At present time the best I can do is show that the LS7 is not overly efficient and note the factors that give the advantages to the Ferrari engine (Higher CR, VVT on intake and exhaust cams, VVI, less internal surface area, more advanced ECU control system).

I certainly don’t. I didn’t say I did. However, I would suspect that the lesser motors are more efficient partly because GM does care about CAFÉ numbers and those lesser variants are used in more cars.

So you would assume that the LS7 is less efficient than the LS3 because of that single weak factor?

Also, when doing the LS7 GM said they basically couldn’t get any more power out of the small block while maintaining emissions and not using FI.

Got any quotes to back that up?

That means they likely would always trade efficiency for power.

Got anything that would suggest that? Do you even have anything that even gets close to implying that?

With the lesser motors they might have actually had the opportunity to trade otherwise.

Got anything that gets close to implying that?

For someone who is offended at unsubstanciated claims you sure make alot of them...

No, you have thrown up a smoke screen of pseudo factors. You have not put together a complete and logical explanation and you certainly haven’t presented the data.

I have put up some very simple factors that you so far have not argued against in any way...

The problem is the graphs don’t provide an explanation. Sure they provide graphs that show you can find some motor info but they don’t prove your point. They don’t prove that the Ferrari motor is more efficient than the LS7. That was a claim that you made without proof. How can we trust someone who makes such claims without proof?

Again you have misunderstood something. Those graphs are not to prove that the Ferrari is better... They are simply there to show that the LS7 is not an overly efficient engine (which was one of the stumbling blocks of claiming that the Ferrari might be better).

I never disagreed with this point. However, I also said it was a method well suited the the engine in question. You just seem to think it’s cheating or something.

Again you seem to be missing something. I never said or implied that it is cheating to use a transmission geared like the Z06. I am just tired of people looking at the mileage figures and saying "geez that is a really efficient engine!" The truth is that the engine isn't really efficient at all (beat by a Racing Wankel engine and a 1960's Jeep engine) it is purely the transmission that allows the car to achieve that mileage.

You didn’t say you were speculating and I haven’t seen this Ferrari data. Where’s the beef? Don’t cry when I ask for the facts.

You didn't notice that I said I was speculating like 10+ posts ago?

Because I admit when I am speculating and I normally say on what basis and accept that I might not be right or that extenuating circumstances may make a generalization untrue in a specific case. You simply assume that you are right but show no proof. I would certainly say the Ferrari is an extenuating circumstance case. More so given that it not only gets lower EPA numbers, but lower mileage numbers in real tests as well.

So the sole factor that makes you think that the Ferrari is less efficient is the mileage? Talk about not taking in the whole picture...

The only thing I’ve lost is respect for you.

and all the time it took to write all these meaningless vicious posts...

BTW you telling me not to get too crabby is hilarious... almost less hypocritical than a snake telling me to stop sticking out my tongue

[hightower99]

You seem to agree with my 16% number. So how is 22% less than 16%? Which is less change, 16% or 22%?

16% is obvisously less change but it happens quicker with the LS7 (hence it isn't as flat).

You seem to be backing your view with non-scaled numbers. Well lets see my lawn mower makes less than 28lb*ft (not lb/ft) at peak power. Thus including when it is not running at 0 rpm it must have a flatter torque curve than the Ferrari! Way to go Briggs and Stratton!

What kind of lamn mower do you have? what is the rev range of the torque curve? (do you have the dyno chart?) Pretty big assumption isn't it? What if it makes peak torque at 1000RPM and can only go down to 900 for reliable torque measurements? then the difference between lowest value and peak would have to be less than 2.8lbft. to be flatter...

I thought you were against blind BS assumptions?

[hightower99]

Quick, which is more powerful, 255.4hp or 187.3kW?
It’s easy when I say which is bigger, 10kg or 10lb(mass). It’s harder when I say which is bigger, 32.41kg or 72.34lb? How about 364 lb*ft/min vs 1.875 calorie/second. Many you should have seen the SI vs English units when talking about enthalpy and entropy!
Funny how your example falls apart with such an easy counter example. Do you now see why you should present all the information in the same units?

Here is my quick guesses:

255.4HP>187.3kW

32.41kg<72.34lbs.

364lb*ft/min>1.875 calorie/second

Mind you I have never worked with calories so I am guessing here...

How did I do?

[culver]

Hey, maybe you would like this... This is an LS7 (tuned) motor. In the video they show the motor returning a BSFC of 0.42 at some points. Perhaps we should figure out if you numbers are truly representative...
LS7" 640hp 555 lb-ft + dyno video screaming 7140rpm - Tremek Car Videos - Street Car Drag Racing Videos
Yes, that is a modified factory motor.

Speaking of the LS motors and comparative data…

Here’s another modified LSx motor showing bsfc number well under 0.4…
Carbureting an LS1 - Tech Article - Chevy High Performance Magazine

Here are some modified LS7 motors showing numbers as low as 0.43
http://www.corvettels7.com/Killer%20...ee%20Dynos.pdf

Perhaps, like the dyno numbers we need to ask if the numbers we are seeing are comparable. I mean I’m seeing an LS1 based motor turning in BSFC that seem a lot better than what you seem to suggest they are capable of.

BTW, why are you ducking the question about education and what you do?

[culver]

16% is obvisously less change but it happens quicker with the LS7 (hence it isn't as flat).



What kind of lamn mower do you have? what is the rev range of the torque curve? (do you have the dyno chart?) Pretty big assumption isn't it? What if it makes peak torque at 1000RPM and can only go down to 900 for reliable torque measurements? then the difference between lowest value and peak would have to be less than 2.8lbft. to be flatter...

I thought you were against blind BS assumptions?

So you do actually agree that 16% is less than 20+%. Good. Now we can see that the LS7 shows less change in torque hence would have a flatter torque curve.

As for the mower, does it mater. If it can't produce even 28lbft of torque it can't have as big a change as the Ferrari. I don't know where you are getting this rate of change (without factoring in % of peak BS). It's like you are doing what ever is necessary to not admit that you are wrong. Sorry, get your head out of your tail pipe and deal with it.


BTW, what about that education and occupation question?

[culver]

Ultimately, it is clear that you know enough to be dangerous but not enough to be an expert. You don't present ideas in a clear fashion then attack those who see things differently.

You need to admit when you are wrong and move on.

I have only two more questions.

1. Why do you think 20% is less than 16%

2. What about that education question? Why won't you answer it.

[Alastor]

It seems like most of the arguments in this train wreck of a thread stem around poor definition of the criteria for performance.

Flatness of the torque is one that is of interest to me.

What defines the flatness of the torque curve?

• 1. Is it the overall percent change in torque across the rev range?

• 2. Or is it the rate of change of torque with engine speed?

I am inclined to lean towards the second since that is essentially the slope of the curve.

But at the same time I can see significance in the first measure.

[Matra et Alpine]

Al, a most important factor in the real world where a driver has to work to get optimum performance is the variation across the range. Rule-of-thumb 10% is "noticable", so a reasonable limit to use .... and at least has a reason for being adopted rather than the manufacturer choosing numbers to make their solution look better This was widepsread in the HiFi/SPeaker industry until some very strict norms were adopted -- so speaker frequency range is determined by it's -3dB points by honest manufacturers

[hightower99]

Hey, maybe you would like this... This is an LS7 (tuned) motor. In the video they show the motor returning a BSFC of 0.42 at some points. Perhaps we should figure out if you numbers are truly representative...
LS7" 640hp 555 lb-ft + dyno video screaming 7140rpm - Tremek Car Videos - Street Car Drag Racing Videos
Yes, that is a modified factory motor.

Hopefully you realise that it is loading the engine and throttling it... The blips you see that go as low as .42 are when the throttle blips closed as the load is turned off then reset. The ECU is programed to shut off fuel when the throttle is suddenly closed. The values that are real are the ones that the runs stabilize on for each RPM spot. And they are not any better than the values I gave you...

Because the values I gave you were using the same engine

Here’s another modified LSx motor showing bsfc number well under 0.4…
Carbureting an LS1 - Tech Article - Chevy High Performance Magazine

I have at least a few issues with that data. First I would say that it looks like the fuel weight isn't calculated properly, and or the fuel flow calculation is not calibrated for use in a carburetted engine... the peak efficiency shows 33% which is very high.

Here are some modified LS7 motors showing numbers as low as 0.43
http://www.corvettels7.com/Killer%20...ee%20Dynos.pdf

This engine is again from Katech... average BSFC for that engine is .471 (26.7% thermal efficiency) This is slightly better than a normal LS7 but notice that this engine has an 11.4:1 CR...