Refining the performance of the '98-'99 300's - Page 2 - PeachParts Mercedes-Benz Forum

aklim · #16 09-26-2007, 08:18 AM

Quote:

Originally Posted by nhdoc

Why is everyone always concerned about the lag when punching the accelerator to the floor? Do you guys really take off like that every time? Mine does the same thing if I punch it to the floor but under most conditions I find the turbo to be quite well behaved. I don't drive like a little old lady mind you, just not WOT except when it's really needed.

And, in the $3 + a gallon time we are in a lighter pedal will result in higher MPGs too, a nice fringe benefit.

PS - I actually drove the speed limit over this past weekend setting the cruise at 65 MPH and drove to NJ and back on a single tank...over 600 miles until the reserve light came on. The car turned in 34+ MPG on 80% highway/20% city, the best I have ever achieved. I might just keep driving it this way as it was very nice not to have to watch for the cops all the time and just let the world pass me by for a change - smiling all the way to the pump.

Fun factor.

Less fun factor. Gotta pay to play.

In a "theoretical" drive at 85, I got 33 with 99% highway.

aklim · #17 09-26-2007, 08:19 AM

Quote:

Originally Posted by ForcedInduction

Only problem with the 606's design is that it's turbo is a tiny KKK K14 so it's already maxed out at stock power levels.

What can we upgrade it to?

#18 09-26-2007, 08:21 AM

Quote:

Originally Posted by aklim

What can we upgrade it to?

Not much without fabrication thanks to it's proprietary exhaust flange. Pretty much anything, even a T3, would be better.

aklim · #19 09-26-2007, 08:25 AM

Quote:

Originally Posted by ForcedInduction

Not much without fabrication thanks to it's proprietary exhaust flange. Pretty much anything, even a T3, would be better.

T3 had an upgrade to a T3/T4 hybrid. Can we do that?

#20 09-26-2007, 08:28 AM

With the right T4 wheel and some ECM tuning for more fuel, I'm sure that would be a sweet combo.

KarTek · #21 09-26-2007, 08:52 AM

I'm not trying to re-invent the wheel, turbo or otherwise (yet...

) I'm just thinking that I've come up with a simple, $25 solution that fixes the initial lag and the acceleration dips. It should also give the car a "friskier" feel. I'm just going after it slowly and scientifically. I also realize that the computer is really the way to go for big gains. I just wish there were more programming options.

I'll wait til later to start going wild with the mods...

aklim · #22 09-26-2007, 09:35 AM

Quote:

Originally Posted by ForcedInduction

With the right T4 wheel and some ECM tuning for more fuel, I'm sure that would be a sweet combo.

I have the ECM tuning already with Speedtuning USA

KarTek · #23 09-26-2007, 03:16 PM

OK, I went out at lunch and hooked up my Ghetto boost gauge and here are some results:

From a standstill, floored the throttle and the boost creeps up for a couple seconds and then the car really takes off when the boost passes about 7 PSI.

The needle literally rockets to some unknown peak (I only have a 15 PSI gauge) that I can only guess is around 20 PSI judging by how fast the needle is moving.

Continuing to accelerate, boost slowly falls as RPM builds but then drops dramatically to around 7 PSI at each shift. This drop is accompanied by a distinct lag which I believe is actually taking place after the moderation in power by the ECU to accomodate the shift.

I'll do some more testing on the way home...

scott19_68 · #24 09-26-2007, 04:26 PM

Quote:

Originally Posted by aklim

What can we upgrade it to?

I saw a turbo from an '05 CDI on eBay a few months ago that looked like it had the identical exhaust flange - I think it was a VNT Garrett. It looks like it uses an electronically controlled wastegate

TTCummins · #25 09-26-2007, 04:36 PM

In the Cummins in my truck they use torque management in the ECU to prevent from breaking input shafts during shifts, I would imagine the newer cars use something similar to prolong the life of the transmission.

KarTek · #26 09-26-2007, 08:58 PM

Quote:

Originally Posted by TTCummins

In the Cummins in my truck they use torque management in the ECU to prevent from breaking input shafts during shifts, I would imagine the newer cars use something similar to prolong the life of the transmission.

That makes sense, though I'd think the ECU would only cut power for a split second to make the shift. It seems like what I'm seeing is just boost dropping after a shift.

The boost drops so much that the MAP sensor lowers the "fuel ceiling" for a second while the turbo catches up.