JonathonK

The new Renntech-tuned AMG GT S makes 611 horsepower and 620 lb-ft of torque. In other words, it's biblically fast.

Read the rest on the MBWorld homepage. >>

unpollo2

why don't they post real world gains in terms of speed? none of the tunes do.

Speedriven1

The issue is this: on the newer biturbo cars with the 722.9 trans, you can run right around 10.8 (give a tenth or two, here or there) with a tune and downpipes. With billet wheels- or even bigger turbos, beefed up clutches, heat exchangers, intercooler upgrades, etc., the transmission steps in and you run ... wait for it ... right around 10.8 (give a tenth or two, here or there). One shop even posted a hugely expensive turbo upgrade PKG that was, by their own calculations, only good for about a tenth in the 1/4.

Based on the few GT S we've done here, I'd say it's a good bet the car will run around 10.8. Give or take.

joseyu

The GTS has the newer DCT and not the 722.9 MCT. Does this make a difference?

Speedriven1

It would probably be worse than the "standard" 722.9, honestly. Look at the Porsche Turbos since 997.1- the DCTs can't hold anywhere near the power of their predecessors (though, in that case, there is more to it). We're dealing with similar issues on the Huracán and, soon, I imagine we'll be dealing with DCTs in the R8 as we start to get into tuning the updated version of those.

Still, though, that doesn't take away anything from the GTS. It's really so much more than just a 1/4 mile platform, you know? Besides, how jaded are we that 10.8 is somehow considered slow?

joseyu

Good to know. I currently have a 15 E63S with heat exchanger, downpipes and a tune. Are you suggesting that I won't gain much with a turbo upgrade because of the 722.9 tranny?

Speedriven1

At this point, the 722.9 is the limiting factor. That's why ... hang on, I don't want to name any competitors' names, so let's just say "Beta Performance" for this example. That's why the "Compensator 7" PKG is being advertised at 10.8 seconds and the "Compensator 9" PKG, which adds a substantial amount of money to the build, is being advertised at 10.7 sec.

We've done a few turbo upgrades for mile guys and guys that want the power and top speed. In general, though, we've been advising our customers to hold off for a few more months until there is a real TCU solution.

unpollo2

Well still a 0.7 to 1 second gain in the 1/4 mile from just an ECU flash is pretty impressive. Do the pipes really need to be swapped to?

Vic55

I find that my tune is enough unless you want more sound. The wheelspin is very heavy even with the most discerning of throttle input. I can not imagine the spin one would have with DP's and a tune (larger tq gains). I gained 110 hp and 134 tq in the sweet spot rpm ranges with just a tune (we dynod my car before and after). I would say my car might be a high 10 second car on a great day with a great launch with great DA but I doubt a full second gain in the quarter.

joseyu

I was considering this package for my incoming GTS until I found out how much work it is to replace the downpipes. Most of the paneling underneath has to come out, then you drop the transmission, remove the torque tube and driveshaft, before you get access to the pipes. YIKES...

JB C63S

Hey Vic thanks for the input. Have you tried different tunes with weistec? I wonder if it might be better to smooth that low rpm torque bump to keep the thing hooked. Does it fall off too much near redline? You know, lose that sporty feel and feel like a truck motor? Any issues at all with driveability? Fuel economy?

Or should I get the tune as soon as I can?

Speedriven1

It's a lot of labor, but it's pretty straightforward. Besides the cost, the primary aggravation of the downpipes (if you have it registered in IL, anyway) is emissions.

Speedriven1

100%.

Vic55

Ive probably tried 3-4 tunes, some with more tq and some with less at launch. I picked the middle option where I have to modulate the throttle a little bit to avoid wheelspin but the one where the car just pulls like a train during rolling runs. The change in acceleration from a roll is incredible with the tune giving so much more useful tq and hp in the usable rpm shift ranges.

I have had my car up to 16x mph at times (Mexican Toll Roads) and the hp and tq has not fallen off but then again I wasn't in the final gear long enough to have such an event. The car really feels amazing with the tune and I got mine early on (circa 200 miles or so I think). I think my fuel econ did go down because my foot got heavier with the added juice but I realize its a pay to play environment.

kumizi

Could you expand a bit on exactly what the transmission is doing? Is it slipping at higher power levels? This behavior also occurs at say 60-130 sprints?

COOPERDB

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Vic

Did you just do the tune or did

you go with the W.1 package

which includes the Weistec

air filters


Thank-You
D.B.


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Vic55

Tune only---