heyhobingo

Hi All

seriously considering the following link and upgrade, currently have a 997.1 GT3 2008, and i just feel the need for more power, and also to try and keep up with those pesky GT2's at the track!

im thinking if i do go ahead, i will most probably need to also upgrade to the Brembo big brake kit.

has any one out there done the 4.0 conversion? and if so was there any issues, upgrade essentials, or just any help or advice would be great!

http://www.fvd.de/de/en/Porsche-0/99...5HP_354TQ.html

Serge944

I build my old 996 using those same pistons and liners.

Here's your homework: https://rennlist.com/forums/996-gt2-...3-4-liter.html

TRAKCAR

Would a real track ready 4.0 not be a better investment?

Dan@SharkWerks

The price is attractive, but there's a lot more to this upgrade than you can see. You need to machine out the heads/water jackets for 105.4mm pistons (the stock 4.0 cars have a different stroke rather than this alone), and the case. These pistons are heavier than 104 etc. and probably a lot heavier than stock which changes the way the car revs freely. Even when Porsche went from 3.6L to 3.8L the pistons were obviously heavier and to counter that Porsche reduced the mass of the flywheel (even in the dual mass mk2 gt3) to help it rev up / down as quickly. You lose responsiveness the heavier you go (which is what we like about these engines in the first place ). When you bore these out so much, the cylinder wall thickness is greatly reduced and cylinder temperatures go up a lot. Paying for the machining, build and teardown by a qualified shop is going to be very pricey and high-risk to get it right the first try. I'd highly recommend looking into all the costs before making an engine kit purchase as this won't be a simple bolt-in and would definitely recommend someone that's installed/built the engine with this kit before.

I also don't understand why they recommend $3000 rods with bigger bore, when the stock rods are fine (titanium)? Sorry don't mean to speak for FVD etc., just commenting on the general idea of it. I think a bolt-in kit would be awesome and lots of people ask for our kit in a bolt-in form, but this engine's so technical; these upgrades are quite complex and expensive. There are also so many factory parts that wear which you should change when building an engine such as this (lifters, valve guides, bearings etc.).

tripleblack

^ sound advice. An experienced engine builder is vital.

tcsracing1

put her on a diet.

Serge944

Dan is absolutely right about the technicality of the engine. You must use special tools and the assembly process is not easy. Installation of the center cylinder on both banks requires extreme patience, because you can't use the factory ring compressor. You must have an experienced engine builder perform this engine build.

Now, back to the hardware: The 105.4mm Mahle pistons have a racing pedigree. They were developed by Brumos and Porsche to race in the Grand Am series. They are forged and are more durable than cast pistons.

The steel liners feature fins to increase the cooling surface area for better heat transfer and are made by Capricorn, which is an F1 supplier.

The machining operation is not complicated. You can buy pre-machined water jackets directly from them as well. The case machining is very simple, you're merely boring out the non-bearing openings of the case. These surfaces do not bear any load, so it's a low-risk operation.

As far as additional things to do, while you're in there: coolant pipe welding, replacement of the chains (they DO stretch), and inspection of the valvetrain (I installed brand new CUP heads).

Mahle 105.4mm vs stock 100mm:

sharkster

We always use liners with additional fins that style for the same reason. Makes so much more sense

RSRanger

Ranger (Sua Sponte)

TRAKCAR

I looked into it and decided a factory 4.0 was easier and in the end cheaper.

sharkster

you did it right buddy

TRAKCAR

He did. Very right.

kk2

How much does that run?

RSRanger

thank you
Plus Champion Motorsport is not done. There are a couple additional internal components in the works
Exciting times.

Ranger (Sua Sponte)

DRPM

I really admire the courage of such an engine build project.

Considering the economics and logic, I opted for the factory 4.0 purchase with full warranty + CPO.

It does raise the question if one could buy a 4.0 engine from the factory?