Hello everyone!


I've read on this forum over and over that people think the original specifications of the M112 engine of our Crossfires are not accurate.


For the N/A: 215hp (218 ps) and 229 lb-ft of torque (310 Nm)


For the SRT6: 330hp (335 ps) and 310 lb-ft of torque (420 Nm)


The Mercedes SLK320 with the same M112 engine depending on source has slightly better outputs. Obviously some people on here have suggested that was solely marketing, as MB didn't want the Chrysler Crossfire to directly compete with their at the time still available 320 model. To me that doesn't make much sense as the new SLK 280 (R171) came out in 2004 with a different engine and new looks.


So, is there any evidence (dyno results, other sources) as to what output our cars really have? Should the Crossfire not run better as it is lighter? How much tuning if any did Chrysler do to our cars in respect to engine, transmission etc. to improve performance compared to the SLK320?


Looking forward to your input!!

 

Go to 6:15 to hear what the design engineers have to say...

 

Glad you posted the video. I had seen it quite a while ago but forgot about it.
You can tell by the way engineer acts he is saying Crossfire have superior performance over the SLK!

Still, I would like to know if anybody wants to take a guess at the real output of our cars in terms of HP and TORQUE!

 

Probably a somewhat open question since there are many variables to deal with. You'll get different readings from different mfg of dynos. And from different fuel types (non-ethanols, race fuels). You'd probably need to do runs on a couple of different dynos with a standard stock XF to get a true baseline.

 

SRT6 motor is the same amg motor they put in their 32.... exactly the same according to shipping records I found to the Karmann factory. They rated that motor 349 hp. So the gains stated based on 330 hp are what are wrong. We are starting with 349... That is the advertising that was falsified to keep MB happy.

 

I have seen several signature files stating measured wheel HP, take a look around.

 

Cool. Can you post your sources?

 

Makes a lot of sense. So in turn I would assume the engine used in the SLK 320 NA is the same as the Crossfire NA. It is what I was getting at but would love to know real output. I have hear people saying the 320 engine in the Crossfire has an output of around 255 PS!
This leads me to another question...since the Xfire is lighter than its MB counterpart, should the performance output in regards to track times not be better as well?
Is it safe to say the Crossfire was superior to the SLK??? I sure still am fascinated by the looks of Crossfire's...can keep up with any performance vehicle in its original price segment today as far as looks are concerned. This I can't say about the SLK that just looks dated!!

 

What's nice about these vehicles, is that they are somewhat a rare breed, with a defined look that will grab the attention of just about anyone. I've loved the look of the Crossfire, and the performance that comes with it, aspirated or not.

I just purchased mine a week ago, spent 4-5 hours on generous detail job, parked it the driveway, and while cleaning my Ram, I couldn't help but notice many vehicles passing were doing a double look, or slowing down. I'm sure that will wear off with the locals over time, but it goes show this style still appeals to others, over a decade later.

 

Having the same identical engine proves nothing actually, it is the ecu tune that will determine the power output. It is tough to say what the c/shaft hp is anyway as you have to have one on a test bed to prove or disprove the numbers quoted. I'll go along with the same hp as the Mercedes though, it means that I have picked up 20hp for nothing.

In the past auto makers have lied about actual hp, and nobody sued them; I guess nobody could prove that somebody was injured or died from having less hp than advertised.

PS
I'd settle for 330 hp anyway, everyone knows that US horses are bigger and stronger than German ones.

 

Nick, the Dec. 2003 issue of Motor Trend did a comparison road test of a 2003 SLK vs the 2004 Crossfire. The Crossfire is 70 lbs. lighter.
The mechanical specifications for both cars were identical, and yet the automatic equipped Mercedes out performed the automatic XF in the 1/4 mile with a 14.84 to 15.18 sec. difference.
Essentially the magazine went on to say that the slower acceleration of the Crossfire was attributed to it's massive rear tire's creating more rotating inertia, which of course takes more H.P. to get moving.

 

The ECU mapping is identical between the SLK and XF.

For all practical purposes the XF is the SLK with plastic surgery turning granny into a super model...

 

Did they do any slalom or cornering comparisons?

 

I saw the link but did not see the source where the mapping was identical. Actually the way I read the thread is the mapping was different thus the greater gain in the Crossfire VS the gain in the SLK.

 

I found this thread on the Forum claiming the SRT6 and perhaps N/A (??) was detuned to output less performance??
https://www.crossfireforum.org/forum...330-349-a.html


If that is true and the engines are exactly identical it would be a computer "de-tune" and therefore the ECU mapping would be different on both cars to keep the Xfire in check compared to the SLK!
I feel like making the Crossfire appear slower made no sense even from a marketing standpoint as the Xfire was introduced in 2004. Even if the Xfire would have had better numbers than the SLK it really didn't matter as 2005 the new SLK with overhauled design and engine was released so it was two different cars from there on out.
I mean, not that it really matters as I love my N/A just the way it is and with the performance upgrades I did but at the same time it is just interesting to know the real output!


What have I learned from this thread? Take HP claims with a grain of salt as it seems car manufacturers can claim just about anything on paper!

 

So, in other words, nothing has changed from the old days, HP #s are still discretionary. More than a few of the motors in the muscle car era were advertised at much lower power figures than they really made and in some other times they were advertised at higher HP than they made. Gee, automakers lied, can you imagine?

 

Only advertised numbers are different.

Actual code in the ecu is the same. The guys that do this for a living confirmed it.

 

Who? When? Where?

 

Nobody reads my posts?

https://www.crossfireforum.org/forum/all-crossfires/70277-eurocharged-crossfire-tune-pulley-sale-2.html#post825572

 

LET, which is now Eurocharged. I went to Chicago more than once for a tune, and we all spent time at the track running side by side as well. No one has de-tuned the motor. Gets delivered, it was a JIT facility, so the motor went straight to the assembly line. There was an AMG video out a few years backs showing a motor being hand built. If you spend any time around the motors, you can see for yourself. Steve had his SlK, did the same build as we do to our XF's...just isn't the same engine room, but many things are the same.
As far as motor trend, automobile, road and track...doing side by side comparisons. It isn't any different than drag racing. NO one lauches exactly the same every time. NO one is going to perform exactly the same each time. So when you see cars within a few thousandths of a second apart, that can very well be driver, not the car...
In fact, I remember taking Matt's stock SRT6 coupe out trying to break the 12's for him and did a 13.1. He had never done this himself, but the car did with a different driver. We could go on and on, but the bottom line was AMG had the motors and Chrysler had the car, and Karmann put it all together....