I would like to remove the 6K rpm limiter that came with my '04 six speed X-Fire. Assume it's a matter of reprograming the computor. Anyone know somebody that can do this for me - or how I can do it.

Thanks,
John

 

I assume you'd also like to remove the motor after over-revving it a couple times J/K.

 

Thanks for your help there "no warning shot" Obviously you don't have the answer to my question.

 

The question does have to be asked, why do you want to remove the limit, its there for a reason? But you are correct you need to hack the ECU.

 

Since nobody on this forum seems to have an answer to my question: 1. 6,000 rpm is way under the safe limit for this engine (for obvious reasons) which limits power output. With a 3.30" stroke, piston speed at 6,000 rpm is at 3,300 feet per minute. At 7,000 rpm, piston speed would be at 3,850 fpm. This motor could easily handle 4,000 fpm for short periods of time. It could handle 3,300 fpm all day long! 2. I'm not much interested in having someone else tell me when its time to shift!

 

The answer is hack the ECU like I said.

 

Taking a good hard look at a dyno graph of your engine, and seeing where the power peak is and where it starts to drop off would be a real good idea. Haha. That determines where the ideal shiftpoint for speed is, not what the engine can handle. You might wanna consider changing your camshaft profile if you're planning to run the engine up around 7,000 before every shift.

 

I didn't say shifting at 7,000 was the optimal shift point. I said the engine was easily capible of it. I haven't been able to find a torque or HP curve on the 215 HP motor ( you wouldn't happen to have one you might share with us would you Eric?), but since the peak HP for the 215 motor is advertised at 5,700 rpm, 6,000 aint maken it as the optimal shift point. 6,500 rpm would be closer to optimal - considering there is an approx 1,200 rpm loss between gears. One thing is for sure, if you wind it up to the rpm limiter (6,000 rpm), the party is over, cause it's like turning the key off!

 

OK, so someone fancies themselfs a engine designer. Thats great that we have a basic understanding of piston speed limitation, but did we put any thought to valve train!

Ever heard of valve float?

This engine also uses a balance/counter rotation shaft and there may be limitations to it.


Mercedes isn't stupid, they are Germans after all.

 

My engine is fine the way it is...plenty enough power to get me in trouble!

Besides...I have no need for my engine to fit loosely into a 5 gallon bucket.

 

No Chief, I'm not a engine designer. Yes, I know all about valve float. I do understand engine basics quite well and have built many engines over the years - and yes, I've blown some up- never stored the pieces in a 5 gallon bucket though. I've also had much success at engine building. I don't have to work under the same constraints as the OEM's do. I'm also not so nieve as to think that they (the OEM's - even the Germans) are always correct in what they do - listen to all the complaints on this web sight. I'm sorry if I have offended anyone on this web sight and that this thread has strayed so far from my original very simple question - which initially recieved a smart-assed answer.

smokin300.jpg

 

Sorry I don't have the answer to your question.

Some people really have no idea what their talking about and should just drive the car and stop playing with it. I'm not saying your one of these people, I just get worried some times.

Best of luck!

 

I was looking for the exact same thing on my Altima SE 3.5. The RPM limiter is annoying.

I found this link : http://www.sr20forum.com/technical-i...-jdm-ecus.html

There may be a similar wire that can be located and disabled on the crossfire.

Hope this gives you hope.

If I find any definitive answers, I'll keep you in the loop, and you reciprocate as well.

 

Here is some research i did on the subject.

Forrum quotes:

On the SRT-6 Renntech ECU Performance Chip increases the rev limit by 200 rpm. They may be willing to set the limit higher if you contact them.

My Upsolute chip advertised raising the limiter to 6,200, although it would indicate nearly 6,400 before cutting out.

Some owners have replaced the crankshaft pulley and
upgraded the ECU with RENNtech - a respected Mercedes performance company that is pricey. Their website is www.renntechmercedes.com then check out the SLK R170
engine modifications.

The only "Dyno Proven" ECU available is from Speed Innovations.

Apparently, Renntech (well known Mercedes Benz tuner) is making performance packages for the 2005 Chrysler Crossfires. If they are capable of tweaking the Crossfire ECU and installing camshafts and ported/polished heads, then you can be pretty sure they are capable of cracking open the 300c ECU and doing mods.

I'm at work right now. Anyone want to call and inquire? 561-845-7888

Looks like good news could be on the horizon for ECU modifications. [IMG]file:///C:/DOCUME%7E1/DELLDI%7E1/LOCALS%7E1/Temp/msohtml1/01/clip_image001.gif[/IMG][IMG]file:///C:/DOCUME%7E1/DELLDI%7E1/LOCALS%7E1/Temp/msohtml1/01/clip_image001.gif[/IMG][IMG]file:///C:/DOCUME%7E1/DELLDI%7E1/LOCALS%7E1/Temp/msohtml1/01/clip_image001.gif[/IMG]

I’m working with Renntech to do a group buy on there ECU upgrade. They will offer it for pulley modified cars only it will add 8-10 HP on the dyno but will increases the drivability beyond that number. The chip mod will not be sold as a separate mod because there is just not that much gain to the stock system. I’m also working on a group buy of a kit that includes both the pulley and the ECU. Here is what I’m trying to get approved 699.00 for the ECU and 1699.00 for the pulley and ECU. Renntech is the only pulley that includes the factory dampener. The ECU mod will be performed with out having to open the box and install a chip on the board thus completely undetectable by you dealer.

ps: the ECU mod will work with any of the pulley kits that are out even the pulleybull.

http://www.yourhotcar.com/product/li...formance_Chips (612) 605-2379

http://www.performanceproducts4benz....=79&pid=109557