Alright, tonight coming back from the store I hit 6500 RPM on my SRT6. That's right, I am not exaggerating... a little tiny bit before the middle mark in the redline zone. So actually about 6450.

Ever since I got the car, I've been testing its awesome acceleration. But it seems about half the time the car just doesn't want to shift and I have to let up off the accelerator as I see it creep too far in the red zone. It seems to happen almost exclusively in the tiptronic mode, most of the time shifting the car between 6200 and 6300 RPM (which is a little much for my taste). When I mash the gas in auto it seems to do alright and shifts about 6000. When I use tiptronic, starting in 1st gear and gun it, I do the right hand flick to manually upshift at about 5800... and it seems to not want to listen to my command and continues up the redzone until I let off the gas and it FINALLY shifts itself.

So WTF could be going on here? I thought we were pegged at 5800 RPM stock, why am I hitting such obsurd rev levels? And... could I possibly have hurt something?

 

dotn bother upshifting, if you take off in tiptronic 1st and go WOT it will shift perfectly for you throughout the gears. tryign to manually upshift just causes a delay.

i would only do the manual 1st gear start off when racing though (such as at the dragstrip), on the road just leave her in drive and enjoy

 

It's pretty sad that the tiptronic in the xfire is 10x WORSE than the autostick in my dodge stratus. If I tell it to shift, it shifts. If I put the car manually in 3rd gear, under no cirumstances (except at redline) will the car upshift for me. This piece of crap upshifts on it's own, even when I manually specify a gear, it wont shift properly at redline, and its extremely slow when I do tell it to shift. IT BLOWS.

But back on topic, 6500 rpm cant be normal. What is the manufacturer specified redline on this car? I read 6,200 somewhere, 5,800 elsewhere. So which is it?

 

according to the attached file (which is from a link someone posted a while back), the SRT6 is rated at 330hp @ 6100 rpm ... and the max engine speed is electronically limited at 6400 rpm

I'm not sure that I've ever seen it hit an indicated 6400 rpm though, although I don't pay too much attention to it since I don't shift.

I thought InMotion had said they were willing to raise the rev limiter to 6300 rpm, which I've seen in a couple data logs is about what it tops out at with my InMotion tune.

 

Are you the original owner of the car? Perhaps the previous owner had the ECU tuned and altered the rev limit.

And MJ: I totally agree with you on the tiptronic. Apparently Mercedes doesn't want the driver to decide when the car shifts. This annoys the crap out of me too. You tell the car to shift and it shifts when it feels like it. You don't tell it to shift, and it will shift when it feels like it anyway. Grrr.

 

I'm on the stock ECU and I data log. The most rpm's I've seen is 6150. You may have a tune that raised the max rpm's.

Les

 

Bill,

Thanks for the specs... it probably was 6400 RPM that I hit, still doesn't make me feel comfortable though... but if i'm within "normal" range then I guess I couldn't have hurt anything.

Well, there was 1 owner before me, a guy who lived in oklahoma that didn't do any modifications to the car. No intake, no SC pulley, no tune. Well, I guess there is no way to prove there's no tune except he told me that he didn't do anything to it and I trust him... he did not strike me as the tuning type anyway... Whenever I eventually get that ECU tuned from LET, we will find out for sure!

 

In first mine also hit the redline..I have to let up for it to shift?!?! I posted months ago about mine doing this and feared it was hurting tranny.