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beepbeep beepbeep is offline
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Join Date: Jun 2001
Location: Sweden
Posts: 5,564


First of all: please don't get me wrong. I like this kind of projects and have some limited expirience in field. I would also like to help a fellow P-car enthusiast with few lessons I learned so he/she doesn't have to do same misstakes. Some of those misstakes can get quite expensive.

Now to begin:

It's nice to buy shiny parts. But parts must fit together. And you must have a "helicopter view" of how well parts fit together before you go out on a buying spree. Otherwise you just have a heap of shiny expensive parts.

We'll begin with the headers. Equal length headers don't matter much on turbocharged engines. Turbochargers live of heat delta before and after turbine. All that sprawling expensive well-welded tubing is just loosing heat to the elements. 935:s had just short stocky headers with unequal headers. It's nice for N/A engines but you will likely loose power with headers on pic compared to short uneqal length headers.

Now to turbocchargers: What kind of turbochargers are they exactly? They look suspiciously small. Also, the hot side looks unproportionally big compared to cold side. This is characteristics of diesel turbochargers. Diesel motors have colder EGT and require bigger turbine sizes... Such trim doesn't work well on gasoline engines. There are quite many diesel VNT turbochargers but very few gasoline versions (only 997TT up to date). Diesels have cold exhaust temps, gasoline motors have not. VNT vanes cannot (could not, untill 997TT) withstand high EGT's of gasoline engines. I'm not saying you have two siesel turbochargers as I don't know, but in case you do you'll find out that they are basically useless. Trim is totally out of whack on diesels and VNT mechanism will fail in gasoline enviroment.

With other words, I find your choice of stocked parts slightly sub-optimal when it comes to achieving max power from you engine desing. Headers will work,albeit not being optimal and VNT's are a big question mark. I don't have any expirience with those and don't know anyone who does. It will be interesting to see the results.

I guess (a very loose guesstimate, from looking on intercooler/headers design and turbocharger sizing) that you will be albe to get around 550-is horsepower from that design, if you get it working and do a optimal mapping.

Happy wrenching!
Thank you for your time,
Old 01-20-2007, 03:33 AM
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