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Discussion Starter #1
Yesterday, I ordered RENNtech ECU new reflash specifically written for our US market 451-431 (71 hp).

Renntech was founded 20 years ago by the former Technical Director of AMG North America. He is known for the development of the famous four valve "Hammer" engine, ''the 186 mph 4-door that runs like a Ferrari Testarossa''.

The dyno they sent me show a nice increase all over the range, with a particular emphasis where it counts: between 3300 and 5300 rpm.

I shall dyno my smart first to establish a baseline. Due to some overseas travel, this will not happen before early October. I shall then send them my ECU, reinstall it and dyno the smart again and post the results here.

Because I am sure some of you will ask, the cost is $795.

PS: the speed limiter is removed. I have no problem with this for two reasons: 1) It shall make running the car at Summit Point more fun and 2) with my BRABUS sport package wheels and suspension, I am sure the smart will handle just right.

:smartje:


RENNTECH // MERCEDES // MCLAREN

PS: I am not associated with RENNtech in any way, shape or form.

 

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Good Luck, and at least , we will get a true assesment of this re-flash of the ECU. Hope you get a great number!!!
 

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Wily, just a question. Suppose down the road smart issues some sort of recall involving upgrading or flashing the ECU; where does that leave you? :)
 

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Discussion Starter #5 (Edited)
Wily, just a question. Suppose down the road smart issues some sort of recall involving upgrading or flashing the ECU; where does that leave you? :)
Good point: I am sure that RENNtech has a free remap program. Most serious tuners do. I shall ask them tomorrow.

Enjoy it! Although I thought you were bashing getting an ECU remap? :confused:
Absolutely not. I am a fan of ECU remaps: most of my cars have been either flashed or piggybacked with good success.

I have been questionning the performance claims of the only - so far -other company in the US also offering remaps for 451s. Multiple experiences with trusted tuners taught me what to reasonnable expect from a remap. The other company's claims are, frankly, not believable, particularly since they refuse to post any proof for their claims and their assertion that all their tuning is done this way:
"We don't do no stinking dyno, real men do it by the seat of their pants" [ok, they do not actually wrote that, but close enough. :p

I drew my own conclusion and decided to shop elsewhere.

As I wrote, I will carefully establish a baseline and share with you the good - and the bad - of this tune.

Forums are a great place to openly and freely exchange information.

I recommend to you all to support this web site by becoming SCOA members. Please enroll!
 

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Our dealership has an orphan with the Renntech ECU installed and BPP exhaust, it makes a huge difference. I am used to mine with the DTH Center Exhaust. The Renntech makes a difference, it's more responsive and you can feel the power in the low end. We plan to DYNO the car next week and will let you know the results.
 

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I do feel it shift faster, it an all around improvement, but I can't justify $800. I am waiting for a turbo/supercharger upgrade.
 

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On my cabrio, you can feel the throttle fully open about 1 inch up from max pedal travel and then, with more foot pressure there is a noticable breakover point to reach the kickdown position.
 

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$800 for less than 10 hp

If Willy finds the added hp is 8 or more, I'll spend $800.00! I'm that deperate for added hp. BUT, I want to know the impact on mpg. I have a heavy foot and never get more than 34 mpg now. So, I am concerned about a ECU change, more hp and dropping my mpg down in the 20's.
 

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Discussion Starter #20
If Willy finds the added hp is 8 or more,
Lowndex, I too would love to see 8 hp, but I expect more like 4 or 5 accross the useful range, or about +10% hp/tq at mid range, tapering down to +5% at higher rpm.

BUT, I want to know the impact on mpg.
There has been some lively debates on the subject, but my experience is that the more efficient the engine, the less fuel you use - as long as you drive at exactly the same speed, rate of acceleration etc.

But we are talking about minute changes here, one or two mpg.

Of course, if you use the new power, then it is most likely that your mileage will decrease... :)
 
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