I have read a few posts and heard a few people mentioning these Crossfires 'waking up' around 2,400 miles for whatever reason.

People seem to think that Mercedes builds a 'break in' into the ECU and forces the car to limit itself.

I have a hard time believing this, and wondered what others thought.

Specifically on the SRT. I've only got 1,600 miles and my car had no trouble running all the way to the redline prior to shifting, so I find it tough to believe that it is 'holding back', unless it is a fueling issue (runs rich when new?).

Thought I'd ask...

SQ

 

Mine woke up at mile 98. The mile it had on the clock when I took delivery.

Joking aside - I heard the same thing that once the SRT breaks in it performs slightly better. Not sure if it's the ECU (doubt it) but might be the engine just loosening up or ??

If your racing your car already - you might get there sooner!!

 

Well, I can't speak on behalf of MB, but I would be inclined to believe that is an accurate statement. I know for a fact that Chrysler products with the 5.7 HEMI do this. Given their similarities to MB, I would guess that the Crossfire also has this "feature" On the 5.7 HEMI cars and trucks it was a VERY noticeable difference. The mileage seems to vary depending on driving style. I've seen an RT Charger driven hard come alive at 2,500 miles. I've seen gently driven Durangos not do it till about 6,000 miles. I remember reading a reference to this in a service book while I worked for a dodge dealer. The ECU does have a "Break-In" mode on those cars that makes the car run artificially rich for the first few thousand miles to aid in break in. Once that mode is cycled off, my customers would tell me the car either "Came Alive" or they saw their fuel economy jump up by as much as 10-15%. So, given my experience with those vehicles, I would have to assume its a good possibility that Crossfires do this as well. I bought mine with 14,000 miles, so I can't vouch from personal experience on our cars.

 

Good post - wish I could find that manual fine-print that says this.

For the record, I'm at around 1,600 miles.

I have been thinking the fuel mileage was a little low...around 18 with city mix. My wife drives it most of the time, and it is driven gently by her. When I drive it, I DRIVE it (it's made for it!).

Just wondered about this due to my recent track outing and fuel mileage curiosity.

SQ

 

I shouldn't make any difference at wide open throttle. The difference comes into play during everyday driving. When it wakes up, you may notice that it is more responsive in the low and mid range RPMs and gets better mileage. But, at full throttle, it's gonna give you everything...

I get about 21 MPG average. Driving the car gently 75% of the time and HARD 25% of the time. My mix is about 50-55% Highway and 40-45% City depending on the day of the week.

 

That's what I was thinking - more fuel (especially at start up), but not much change at high RPM or WOT.

The car was screaming last night, with no reason for me to believe it was running fat.

SQ

 

mine run's like a scalded dog.
mpg 24 660 miles.

 

Wait a minute, it will get better.

 

I bought my car with less than a hundred miles and am now about to hit 4K. The motor has definitely gotten faster in the last 2K. We'll see how much as I am going to the track this weekend. I will however have new mods as well...

 

When I bought my new SRT6 Coupe, it had 12,777 miles on it.
I noticed that by 12,778 it had woken ME up.

 

i got about 1,200 miles now, the thing will still run.

had a mustang cobra on me in pigeon forge tn today.
when we got to a red light he said he had 550 hp
i told him he had me out numbered, lol.
the cobra sure didn't sound like a 550 hp mustang ...

he said he like my car and he knew about them and how quick they were ...
can a crossfire srt take a stock cobra
i ran mine up to around 130 last night from 80 to 130 then i let out of it.
was not bad at all...

 

Stock Cobra? no such thing lol...Stock for stock it should be a drivers race. But intake/pulleys/tune give that car another 150 to the wheels. I hang out with a group of cobra owners who were at the track with me saturday and they were all in the 11's with one in that ran 10.84@131! They all look and sound relatively stock.

 

Depends on the year of the cobra.

The '03 and newer are factory supercharged, they would likely beat us unless they were just ignorant and dumped the clutch and roasted the tires.

The '96 - '01 are N/A DOHC 4.6L, we'd have no trouble with one in stock form.

The '93 - '95 are N/A 5.0, we'd have no trouble with one in stock form.

One thing about mustangs (I own two)...they are cheap and easy to mod, and also easy to keep quiet. So, just because it doesn't sound like 550 hp, doesn't mean it doesn't have it - ESPECIALLY the newer S/C cobras. A simple pulley on the blower, a new tune, and a few other small mods will get it into that range.

SQ

 

i had a '04 gt stock that ran fair, i guess i would hope he would miss a gear...
if i was to race one ...
any of you drivers done any feel of the seat mods to the xfire.

chip - cia - ect and how much hp can we get out of one of these
11 sec is quick in the qtr mile.

need on of these. lol.

http://videos.streetfire.net/video/9...33c6031102.htm

 

Mine is at 2,600 miles now and it's DEFINITELY waking up in a hurry. I have just started easily hearing the supercharger in the last 300 miles.

 

Let me qualify this by saying that: I know this is true of some types of lysholm superchargers and believe this is one of them, but can't say for certain it is... I believe that this supercharger has a break-in period, which may contribute to the additional whine and added pep after about 2-3k miles. The lobes on the superchargers are actually coated with a urethane-type material that makes them slightly oversized fitting in the housing. They are meant to rub against each other and wear into each other so that they are an exact match. It improves performance in the long run and lowers the manufacturing cost dramatically for the level of precision delivered. The downside is that it takes more power to drive the charger due to friction during the burn-in period. This additional power requirement results in a loss of power at the crank and reduced fuel economy.

 

will let you all know soon, i got 1,400 miles now.

check this out.

http://videos.streetfire.net/video/9...33c6031102.htm

 

Learn something new everyday. That does make very good sense all the way around. I could easily see how that could do it. I would be willing to bet that you are correct.

The one thing that you theory can't explain however is the ABRUPT nature in which they wake up. It's literally an overnight thing, like turning a switch. One day when you go out to start it, it just "wakes up" I do believe what you are saying with the, but it just doesn't explain the sudden change. I am inclined to believe it is a combination of BOTH of these theories.

 

ok,i got 2350 miles now ..seems to still run the same.. no big change
might be because @ 200 miles i ran the **** out of it ..