My friend got an Audi S5 a little while ago, it's the first fast car he has and let's just say that he's been kinda cocky since he got it. The other night he was on Sunset with a friend of ours when a CLK350 with a couple of 20 year olds came up next to him.

Other Driver: Hey man, nice car
Friend: Thanks
Other Driver: So those are really fast right?
Friend: Yeah, it's really fast
Other Driver: You want to do a quick run? I know you'll win but I want to see by how much.

So they did a rolling start and the CLK350 put a car length on the S5. They stopped at the next light and the driver of the CLK350 said, "it might be a CLK350, but it's chipped"

Lol. Needless to say, it put my friend in his place. But seriously, a CLK350 can be that quick with just a chip?

 

soungs fishy to me

 

Could be CLK550 badged as 350?

 

There's no way a chipped 350 can be quicker than an S5 is there?

 

Hahaha! If I were him, I would have listened to see if it sounded like a V8 at WOT.

 

a chipped 350 wont beat an S5. heck...a fully modded CLK350 with headers, tune, intake, full exhaust, whatever else....wont keep up with an S5

something is fishy here

 

I don't know man, a friend of mine who drives exactly the same way I do, beat a previous gen. manual Mustang GT in a C350 loaner. from dig to 80 2-3 cars and the Mustang wasn't gaining.
His shifts sucked, but still.

 

the Audi S5 is faster than a stock C32. Even the new mustang GTs arent faster than the C32.......As far as C350s go, i have had a loaner C350 and they arent slow....but they trap around 95 or so in a 1/4 mile on a good day IIRC....and the mustang GTs (if its a new one you are referring to) trap above 100...so i'm guessing someone was granny shifting. idk.....either way......i dont see a CLK350 keeping up with an S5.......a CLK550 isnt as fast as an S5

 

looking at the raw numbers, i think a CLK550 could keep up with an S5

 

i stand corrected

 

Twice; the C350s trap more like 99+, 14.1 sec @ 99.1 mph in this test:
http://www.motortrend.com/roadtests/...ecs_price.html



As to the original race, a CLK350 shouldn't beat an S5, chipped or not....chips on n/a motors are worthless for the most part, unless it's a SW detuned motor a'la the C63. The S5 traps at 105-106, you'd need an extra 60-70 hp out of that 3.5L 6 to get there, and that's going to take extensive engine mods or spray.

 

Would a chipped 550 beat an S5?If it wasn't a 350 that's just awesome on behalf of the driver! lol

 

A stock CLK550 would probably pull an S5, or at a minimum run even with it. Again, there've been objective tests run of tests on normally aspirated motors, and no discernable gains were made (see "Chips Ahoy" article in C&D, where they tested seven chips by Dinan, others, and got no gains). But fortunately, a 550 woudn't need any gains to make a good showing here.

 

As everyone else has said, no way the CLK350 keeps up... CLK550 would run even or pull, depending on mph range of the run. A properly-driven S5 would get the jump on a 550 out of the hole and probably stay there 'til 80-90 mph.
350 though? Not unless your friend in the S5 was shifting well below redline, or started his run too low in the rev range. The 4.2 is useless below 3500, and still pretty anemic until 5k or so.

 

Your friend can't drive!

 

I ran a S5 once. He got me off the line but I reeled him in later on. After the run he tells me I didnt know Benzs go that fast.

 

The average 1/4 mile for an S5 is roughly 1 second better than a CLK350. That's somewhere in the neighborhood of 6-7 car lengths around 100 mph. An S5 is AWD and not very torquey so the only way your buddy could have screwed up from a slow roll is on the shifting. I wouldn't expect the CLK350 to win in a million years with just a tune.

 

That's what I'm thinking and then allowing for a few minor factors, very plausible outcome.

That isn't hard to do

An unprepped, bone stock SLK350 with TC on ran consistent 14.1s (2.1/2.2 60fts) @ 98-99mph at Sears Point a few years ago too. Are the CLKs geared any different?

Due to torque management and emission restrictions, that statement is more untrue now than it was before. Btw, what do stock vs. chipped C63s pick up on the dyno?

 

Don't think so...afaik the E350s run right around in there as well, so I'd expect a CLK350 to be in this ballpark, within a tick or two.

I did explicitly state that in the case of SW delimited motors, i.e. where software has been employed to restrict the HP output of an engine, it's possible to get gains in a chip, but the only cases I know of where this is employed is the M5 (in "400 hp mode") and the C63 (supposedly, although I haven't investigated beyond what I've read; the manufacturer could simply be underrating the motor, as they did the 5.5L motor in the CLK55, and claiming it's done w/SW).

But aside from such a case, there simply aren't that many gains to be made by timing tweaks. Here's a good article from Hot Rod that illustrates this.

They took a 360CI V8 with a 10.5:1 compression and tested its horsepower/torque output with several different octane fuels (87 octane, 91 octane, 91 octane plus "octane booster", and 100 octane race fuel. They also varied the timing to try and optimize it to the fuel rating, recording horsepower numbers at several different timing settings for each octane rating.

Guess how much extra horsepower using 100 octane fuel with optimized timing netted them over 91 octane with optimized timing?

[corrected--oops!] 7.5 horsepower.

It is also illustrative to note that their maximum horsepower numbers at *all* octane ratings, from 87 octane all the way up to 100 octane, came with the *same* setting of timing advance: 36 degrees. Deviating from this setting in either direction, regardless of the octane of the fuel being used, resulted in lower measured horsepower and torque. The only octane level that benefited from a different level of timing advance was 114 octane, wherein maximum power was reached by retarding, not advancing timing, to 31 degrees of advance.

Their conclusions:
I have no idea. If they are actually using SW to detune the car, then I'd expect the change to be substantial; if they are not and are just derating it for marketing purposes, then I'd expect it to be slight.

 

Good info, thank you. However the net from 87 to 100 was 7.5hp but that is pretty small.

However, modern fuel injected engines are a little different and the motor in point was an unrestricted 360ci with a carburetor.

Factor in fuel injection, in some cases 2 spark plugs per cylinder and/or 4valves, a similar sized motor making 425 to 500+hp with full emissions, a 6400rpm+ redline, etc., the octane differential can be more significant. Free up the emission controls and now it's different ball game.

For me, I went from 398/422 to 413/432 running 96+ octane vs. 91 octane. My baselines before tuning were 385/382 on another dyno and canned tune 388/402 on tuning dyno.

 

All of these factors were present in the cars that C&D tested: all were fuel-injected, several had multiple spark plugs per cylinder, high redlines, etc...this wasn't done 20 years ago, it was done more recently, within the last several years, not exactly the stone ages in terms of engine development.

Your differences were only in the 3-4% range. You can get wider variances than that on a single dyno, let alone between different dynos. To truly verify this, you'd need multiple averaged pre-and post-chip runs, on the same dyno, on the same day, with in-between cool downs, along w/measured performance differences under the same conditions.

 

I came from an 06 S4, same engine as the S5. They are pretty slow. Only version of the 4.2 V8 which has the performance to match the lovely sound it makes is the one you have shared by the B7 RS4/R8. As you know, I'm a huge fan of RS Audis. The S line is now little more than a marketing gimmick, S6 and S8 being prime detuned examples.

 

Probably rebadged 550 ive seen a few.

 

No no no, I think a CLK350 would give a CLK550 a good race...don't you?

After all, it was you wrote that a CLK550 could give a CLS55 a good race, and a CLK350 is down 100 hp on the 550, just like the 550 is down over 100 hp on the 55....so I'm certain you'd agree, yes?

 

if clk550 weighted 330 lbs more than clk350 it would be a fairly close run.
They are same body and only have 150lbs diff with clk 550 having more Hp and TQ.