M&M

The response I'm talking about has nothing to do with boost. Even if you on boost, a turbo or SC car takes a fraction of a second to respond to your throttle. I can't believe you don't see what I'm saying.

AMGE

MaM
NO FRACTION of a second throttle response with S/C, but after what you have been writing I can see why you don't see it.

M&M

Dear AMGE

It simply takes a lot more time to spin up a supercharger to 70,000 RPM (or whatever it spins to) and have it spinning long enough to make full boost compared to simply opening a throttle plate and letting ambient air pressure nearly instantly flood the intake manifold, the way an N/A car does. In fact, if you look at the REAL top end sports cars, not only are they N/A, but they do away with any intake manifold at all and use individual throttlebodies to minimize the time it takes to achieve full throttle.

AMGE

I am not sure you have a point, but to help you better understand mine John Force is running a S/C and he is running a 100 gallon per minute fuel pump.

Now how's that for throttle response Mam?

E55AMG99

So this statement makes it clear that you don't understand belt driven superchargers.

M&M

Well that means he's making big power. Doesn't mean he has great throttle response.But hey, maybe it's a moot point. I'm sure the response is good enough for 99% of the people out there. This is not a debate about which is better. But it is a generally accepted fact (by everyone on planet earth except you guys) that throttle response is better on NA than FI. Sure S/C is bettter than a turbo car in that regard but it will never be as crisp as an NA car.

But Maybe VAdim can answer these questions for me. There must be some bypass or re-circulating valve in the SC AMg's for when one lifts off? So when one re-applies the throttle it will take a fraction of a second for the boost to build in the pipes again, not so?

2ndly, are all the SC AMG's intercooled? If so, I assume the intercooler is at the bottom of the front bumper? So then it's not that simple as applying throttle & letting mother nature rush the air in. The air has to go to the intercooler to get cooled & then flow back via the pipes & then go in. You see where I'm going with this?

For a family sedan, instantaneous throttle response is probably not high up on the criteria, but the point I was making is that it will be better in the E63. Even a high compression FI car with ITB's won't have the razor sharp response of a good NA car.

M&M

Does it have an intercooler? Does it have boost pipes? Does the air go straight into the engine or does it go via the boost pipes? Maybe e-mail Gordon Murray who designed the SLR & take up with him why he says SC cars have mushy throttle response (and he was talking about the SLR BTW).

E55AMG99

Yes, it has an intercooler but no it does not have "boost pipes". The air passes through a water filled radiator directly below the SC and into the engine. The water is pumped to another radiator under the front bumper.

You are likely taking Gordon Murray's comments out of context. In order to get the kind of throttle response you are talking about, the engine would not be very streetable, economical, efficent and emissions friendly.

AMGE

Don't know what U R smokin over there???? but its now very obvious to me that whatever it is I don't want any... best regards mam.

M&M

OK Ladies & Gentlemen, who on this forum believes they know more than a former F1 Mclaren designer, designer of the McLaren F1 roadcar & the SLR. If you do feel free to send your resume to McLaren:

http://zatzy.com/printthread.php?t=201210


JB: Presumably working on the SLR you’ve come to embrace the supercharger as a different way of gaining performance?

GM: No. Given a totally open choice I’d always go for normal aspiration, for everything: weight, complexity, efficiency, drivability. Supercharging is much better than turbocharging for all the obvious reasons but also has its drawbacks. If you want 500 horsepower, net, you’ve got to make 700 because 200 goes to driving the supercharger, and then you’ve got to cool that power. The small throttle response problem you can get over with bypass valves and things. It’ll never be normally aspirated, but it’s certainly a hell of a lot better than turbocharging.


And here he talks about the NA McLaren F1's response:

"that the combination that gives you the instant buzz when you bang the throttle open"

So in his words a SC car's throttle response is better than a turbo car, but "it will never be NA"

egxpimp

M&M i tottaly agree with what your saying trust me i race on the track and what M&M is saying is true he aint BSing....

E55AMG99

With what? For how long? How many different car and engine combos? An expert already and still a teen? Doubtful.

M&M

Just want to re-iterate before Impro comes on here & throws his toys, that this is not a "my daddy can beat you daddy up" contest. It's just a pure technical discussion on the merits of NA vs FI. I own cars from both sides of the camp & they both have their pros & cons. We are all here to learn so I hope for a good technical discussion where maube I can learn how the AMG S/C works without someone calling me names.

K, thanks, bye.

M&M

Hey buddy, have you sent your resume to Mclaren yet? I hear Ferrari's also looking Just kidding man. :p

E55AMG99

Agreed!

VelocitE55

M&M, your obviously incredibly unfamiliar with the layout of the M113K engine and as such, you should stop arguing about it until you understand it. The Liquid-Air Intercooler sits beneath the S/C (The S/C and I/C are literally attached to eachother) and the whole unit sits between the heads. Theres no piping from the nose of the car that the cooled air has to flow through, its sent straight from the S/C to the I/C to the Intake Plenums. The whole system is continuously under pressure.

E55AMG99

Most likely, an NA engine from the MB stable (like the one in the SLR) would never pass emissions nor fuel economy requirements given the timing they had with the SLR. They would never have been able to meet the delivery date in time if they had to develop a NA motor with those power figures.

The F1 and the SLR are night and day different when it comes to weight and drivetrain. The SC motor works very well in a heavy automatic because the torque curve is so fat at low RPM compared to a turbo and a NA engine. A lower stall torque converter can be used to aid drivability and fuel economy.

Reading the early part of the interview is kind of laughable. He's tossing AWD out as taking away from the driving experience. Obviously he has never driven the Lamborghini! Also, if it wasn't such a huge benefit, why do the Audis dominate wherever they race until the sanctioning bodies penalize the with weight?

I think he has some strong opinions that are not being taken completely in context. Calling the Buggati Veyron th emost pointless excercise on the planet makes his opinions sound even less credible.

M&M

OK Velocity, that's the info I was looking for. Thanks. Even if the intercooler sits close by, it's still a longer path than an NA car (especially one with ITB's) take? AM I correct?

And Gordon Murray obviously started the SLR project with the same supercharged 55 engine from the E55/SL55. He said he managed to get over the "small throttle response problem" by using "bypass valves" in the SLR. What does he mean by that. I assume the normall 55's don't use these valves. Is it maybe that this throttle response problem in the 55k's (albeit a very small problem) was not good enough in a supercar's appication & they had to take steps to alleviate it? What do you think?

E55AMG99

LOL I no longer build engines for profit nor do I race professionally anymore.

Funny you should mention Ferrari. It was suggested that they adopt forced induction several years ago to meet their power goals while keeping emissions and fuel economy in check. The response from the top was a resounding NO becasue it would change the "song" of the engine.

E55AMG99

Intake tract is no longer becasue of the IC.

The thing I can't understand is how GM is claiming the E55 has a throttle response problem. Maybe it is the SC clutch. However, once it is engaged, throttle response is instant.

Even the throttle respoonse in my GMC Denali picked up tremendously when I added the suppercharger.

M&M

Well maybe we can agree to disagree 'cos I agree totally with him. A 4WD Supercar? Why? Like he said so you can drive it everyday, in the snow & ice, etc. Who drives a supercar everyday? You will have other cars for that. And liek he said you want a driving experience & not a car that covers of you like a 4WD car does. Maybe in a familty car you want that. And I bet the fastest cars on most circuits on the planet are RWD. Check out the top 30 fastest cars around the Ring. Here's GM's comments for those that missed it:


The most pointless exercise on the planet has got to be this four-wheel-drive 1000 horsepower Bugatti. I think it’s incredibly childish this thing people have about just one element – top speed or standing kilometre or 0-60. It’s about as narrow minded as you can get as a car designer to pick on one element. It’s like saying we’re going to beat the original Mini because we’re going to make a car 10mph faster on its top speed – but its two foot longer and 200 kilos heavier. That’s not car designing – that just reeks of a company who are paranoid. It’s time we stopped saying ‘let’s try and beat this or that’. It just happens to be the McLaren in a lot of cases because it’s still considered to be the quickest, the best, the lightest, the stiffest, the whatever. If somebody came along, including Ferrari, but particularly, Bugatti, and said, ‘We’ve driven the McLaren, we’ve seen what makes a good car and we’re going to take all those elements and move it on a step – the technology, the weight, the safety, the size, that packaging, the luggage space, the torque, the way it delivers power,’ I would be going, ‘good for you. We’ve had our 10 year reign, take the crown.’ I know it’s going to cost millions to develop the Veyron, a monster thing that you can never see out of, can’t park anywhere, four-week drive, four turbos, 1000 horsepower. It may go faster but it won’t touch the F1 in any of the other important areas/ that’s what’s pathetic about it. I think it’s about time companies stopped doing that. I wouldn’t do it, I wouldn’t belittle myself to do that.

Four-wheel drive will never give you the experience that the McLaren gives you. It’s probably much safer when it’s wet and slippery, and more people could drive the car near its limits, but that wasn’t the aim with the F1. It’s absolutely true that 90 percent of the people, 90 percent of the time won’t drive the car at 90 percent of it’s capability. So why start with 4wd and carry all that weight and inefficiency? Ultimately for making the car easier to drive and getting a bit more grip, you’re losing out on the ultimate driving experience. Just 4wd is enough to say they’re never going to get an F1/ If you’re trying to build a car that more people can drive, more people can handle the power, 4wd is probably one of the easiest ways, but with the F1 we didn’t set out saying ‘we’re going to make the quickest car and we’re going to make it really easy to drive, so that 90 percent of the population can drive it’. No way. It was almost the opposite, it was, like this is probably going to be the last real car, without ABS, power steering or power brakes, and you’re going to have to push a bit harder on the brakes and to park it’s not going to be that easy but it’s not going to have anything getting in the way of the driving. It will probably be the last one like it. It’s a shame. I’d so much rather see that money and effort – sorry no, not the money, they can probably afford it – all those engineers and all that effort go into some new direction of sports car, maybe ultra lightweight or ultra nimble or ultra safe or something else rather than just trying to build the fastest car in the world.

E55AMG99

Good idea! Good discussion however

M&M

Sweet, I have another theory that makes an interesting discussion. Maybe another thread.

But on the throttle response issue, it's hard to explain in a post, but when you apply throttle I reckon NA has much more adjustability, but maybe the biggest difference is felt when you come off the throttle. Especially on a circuit where you aren't lifting off completely, but just lifting a little. The FI car seem to carry on going as if you are still pressing the throttle.

I guess part of it may be the intricacies of doing a throtte map when you have a huge torque "plateau" in the mid-range. I mean if you have 500 lb/ft under a few inches of right foot travel, going from 1/2 throttle to 5/8 throttle might not feel a whole lot different.

AMGE

MaM
Possibly you should quit reading so many magazines,
and maybe not complain about name calling... since you come on a thread and make sacastic statements like:
It's obvious you haven't driven
or
you haven't driven a good one
or
the rest of the world is wrong
or
nothing is going to beat a N/A car
or
s/c 55's are being eliminated due to guys modding them

these kind of jabbing like statements aggravate some people.

M&M

Ok sorry man, but that's just the way it is. Nothing personal, but if you say an E55's throttle response is as sharp as an S2000, then you obviously haven't driven an S2000. Most OEM's are turning to NA for performance applications. Seems AMG agree with me as well.