I saw your post on 6speed I think ?

 

There are US tuners who can bolt big Garretts on and give you mega US hp but if you want to keep the character of the engine (and car) intact then you are better off with a properly tuned VTG job.

There is a test on the Manthey 600 - numbers from it are on this site:

http://www.einszweidrei.de/

The Manthey car tested was a bit lighter weight than stock with carbon doors and hood and wheels but it also wore big tyres and their aero package so more drag.

The main problem with the GT2 (and this is particularly pertinent for your location) is that in standard form it runs high air intake temperatures - we have a poster on here with a GT2 from your general location and he has experienced big power loss with the sort of ambient temperatures you get..... Any tuning of the GT2 (in its standard engine configuration ie VTGs and expansion manifold with stock intercoolers) will be limited by this,

Cargraphic sell the 600PS/800NM kit developed by RS Tuning which a few forum guys have purchased, this will work within the limits of the standard intercoolers but even this will lose power when your ambient temps get over 30degC......

Your question specifically mentions instant response and reliability. Tuning the VTGs effectively seems to be a hard thing to do but the RS kit seems to be the best in this area, checkout the data on their VTG 997tt 624PS/826NM - it has amazing response and I can report from my RS Tuned engine that this is a trade mark feature of the RS engines - reliability is a given with this race engine builder.

Back to the Manthey kit - With his reputation it will be well resolved, I believe his VTG control and ECU programming   was done by Ansgar Weissen who has a good reputation and it is a viable alternative to the CG/RS kit......

The other thing worth mentioning is the torque delivery (and size of the torque ie sub ~850NM) - the smooth delivery of the RS Tuning really suits the GT2 and enables traction to be maintained - something which can be easily upset by a peaky tune - I would imagine the Manthey to be similar in this regard. 

personally I wouldn't reccomend any others for our expensive unique cars Smiley


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2009 997 GT2 659PS/827NM DIN