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    Modifying a 996tt motor with a 3.8 or 3.9 kit

    Looking of information (pros or cons) about adding the 3.8 or 3.9 litre kit to the 996tt motor.

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    RC, I understand there is one company in Germany, located by Porsche, who does the 3.9 litre kits. Do you know the name and number for this company?

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    I have to confess that I don't know any Tuner who offers a 3.8 or 3.9 kit for the 996 Turbo. I know several Tuners who do that on the GT3 engine but not on the 996 Turbo engine. I asked a bit around and main reason why Tuners don't modify the TT engine to 3.8 or 3.9 is ... cost. It doesn't make sense on the TT because Tuners usually can obtain up to more than 600 HP without having to play around with the displacement. And the kits over 600 HP are usually not approved by german authoroties (TÜV/DEKRA).

    I can't exclude however that one or two Tuners are doing the displacement thing on the TT engine but probably not for the german market. Sorry.

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    hi cjv,

    the 3,9 litre lit is made by "shk Fahrzeugtechnik u. Vertriebs GmbH" and this GT3 is not too slow - faster than any tested tt or gt2 on hockenheimring...
    Look here: http://www.track-challenge.com/main.asp?useframe=tracktest1.asp?ordering=8

    regards
    rsv

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    The GT3 modified by SHK has the normally aspirated engine.
    cjv asked about a 3.8/3.9 kit for the 996 Turbo.

    Regarding the SHK GT3: the performance in Hockenheim doesn't have anything to do with the 3.9 displacement but mainly with the suspension/wheel/tire setup.
    420 HP out of a 3.9 engine isn't impressive at all.
    The GT3 from the 24 h race on the Nuerburgring had 460 HP without a displacement increase.
    And there are in fact two 996 Turbo which are faster than the SHK GT3 3.9 in Hockenheim (Kleiner Kurs):
    Gemballa GTR600 in 1 min. 09,464 sec.
    Techart Porsche GT Street S in 1 min. 09,537 sec.
    Both cars are around 150 kg heavier than the GT3 3.9 by SHK. Any more questions?

    A personal comment: the real quality of a car shows when you test the stock version back to back with other stock versions. It is pretty easy for a good Tuner to modify any car to a great track car but that's not the point.
    The tested SHK GT3 3.9 was actually a camouflaged race car, read about the suspension/tire setup.
    Even if the Gemballa/Techart Turbos I mentioned aren't stock, it shows the potential of a good basis and the potential of Tuners who put BIG money in showcars.

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    RC, I wonder if SHK makes the cylinder inserts and pistons. The inserts should be the same. I believe the pistons would be somewhere between 8.5 and 9.0 to 1 compression ratio. I understand FVD Germany makes them or obtains them from someone. Just as an update. I have received the Ruf titanium conrods, GT1 oil pump and GT3R valve springs. I have on order the GT3 Cup heads, valves and tappets (lifters). Still working on the cams and 3.9 kit. Once I have everything we will start the machine work (port/polish heads and machine for metal o-rings, cross drill/knife edge crank and boattail the case.) This will be followed by ceramic, dry lube and heat dispersant coatings. When all this is complete we will break down the present motor, balance and re assemble and see what we get.

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    I found out today no one makes a 3.9 kit for the 996tt motor. I understand a company in Germany makes a 3.8 kit for the 996tt. I believe their name is Wasser. Does anyone have any information about this company?

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    RC, I finally obtained solid information. What can you tell me about a German company called Wossner Performance Pistons?

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    RC, I also learned FVD Germany has a 3.8 kit. I don't know if they make it or buy it from someone else.

    Decided aginst 3.8 kit

    After gathering information about the 3.8 kit and the turbos I have decided against adding the kit. This was due mainly to longevity questions answered by Richard Walton at Jerry Woods Enterprises.

    Re: Decided aginst 3.8 kit ... good decision

    Doesn't make much sense and increases cost very much. Longevity wouldn't be an issue if you're willing to invest big money but the results are not even close to be worth it.

    Re: Decided aginst 3.8 kit ... good decision

    RC, the concern was keeping the heads glued to the case with the power and torque we will be running up to 8000 rpm's. Blowing a head gasket with the larger diameter sleeves is our concern. The heads are still being machined for double o-rings and 190,000 lb. head/case studs are being manufacturered. With all this we still have a concern. The cost of the 3.8 kit was less than $4,200.00 US dollars. The cost of labor and materials without the 3.8 kit is still going to be about $23,000.00 US. If not for this concern I would still use the 3.8 kit.

    Re: Decided aginst 3.8 kit

    FVD uses Mahle for all their piston/cylinder kits.

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    RC, I have finally found the manufacturer of the 3.8 L
    (102 mm) kit. They make two different versions. Not sure which one would be best for my application. The manufacturer is Wossner. The website is www.woessner-piston.de . They are located in Germany. Can you tell me anything about this company?

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    Hi cjv!
    Woessner is a well known german company. They provide a similar quality as Mahle. Hope this helps.

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    R.C., I had Carnewal send a 996-103-915-73 piston (100 mm stock 996tt) to Wossner so they can custom manufacturer a set of pistons in the 102 mm size (3.8L). They presently have the 102 mm liners in stock. This is the last of the parts needed to start assembling the new engine.

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    Just can't wait to hear about the results.

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    RC, I'll give you a quick menu of the parts and what is being done. Have new case which is being boat tailed. GT1 three stage oil pump. GT3R crankshaft being cross drilled, lightened and knife edged. Ruf titanium steel conrods. GT1 case and rod bolts. Wossner 3.8L pistons/liners. GT3 Cup heads being ported/polished, re worked for 102 mm liners and machined for metal O-rings. GT3 Cup lifters and valves. GT3R valve springs being cryogenic and heat dispersant treated.

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    cjv, I talked to a friend of mine about your project. He's a very nice guy and very familar with Porsche engines too.

    He would stay away of Wössner pistons ('poor quality') but look for 993 GT2 race pistons (maybe Mahle). He would also be careful with cr, as the race engines run high cr with high octane race fuel. He would not use titanium con rods and he told me, that the 993 GT2 race engines use Carillo steel rods with success. The Cup heads work well on the Turbo, and the GT3R heads use titanium valves. Finally he said you should check if the GT3R valve springs are strong enough for the (heavier) steel valves of the Cup.

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    I agree with CR, I wouldn't go for the titanium con rods unless you want to race your car and drive it for a short time only.
    Not sure about the Wössner quality, I talked to somebody who assured me that the quality is Mahle alike but this guy also told me that on custom manufactured parts, quality can vary a lot and experience (and some luck too) is everything. I'm not sure how much power you want but let me give you some figures about already tested engines:
    "Reliable" 440-460 HP are possible on the normally aspirated GT3R engine. Turbo charged, around 650-700 HP are possible without compromising the reliability too much but the parts used are VERY expensive and almost everything has to be modified (as you already learned ).
    My usage of the word "reliable" should be used with some caution though.

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    CR, this is the first time I have heard any comments about "poor quality" from Wossner. I know of his pistons being used successfully on one very successfull championship car. Otherwise I have had no experience with them. I believe RC on an earlier post said they were known for their quality products???? Did your friend say why he would not use titanium conrods? I am aware you cannot x-ray them for cracks but I would replace them when I rebuild the motor again. I was looking for the added acceleration provided from the weight reduction. I chose not to use the GT3R heads and the titanium valves that come with them for a few reasons. Not enough meat between the valves for my liking. Do not intend to rev more than 8000 rpm's. Better longevity with the steel valves. I really don't intend to track the car much at all. Regarding the GT3R springs, we are checking the spring pressure because of the same question you have raised. If the pressure is OK we will use them. I really appreciate your feed back. Thanks again.

    Re: Modifying a 996tt motor with a 3.8 or 3.9 kit

    RC, why are you and CR afraid of the titanium valves. Not being critical, just would like to hear some sound reasoning or backup. I don't intend to drive the car much. This motor would be a second motor to my existing motor. Would like to see it last 50,000 miles before rebuild. You must also remember the car would be pushed but not often. The ECU is equipted with dual programs (A/B switch). A for 91 octane B for 100 octane. The car is also equipted with a four way electronic adaptive boost. I call run four boost levels. Needless to say most of the driving would be @ 91 octane and 1.1 bar boost. Regarding HP, car would be capable of mild to wild depending on octane, chosen map and boost. Let's say from about 482 to about 680 rwhp. Please don't worry about your comments, i.e. "cautious." Freely give me your best input. Whatever I chose to do is on my dime and my risk.
    Thanks for the input.

    I have to admit that I admire your...

    ...dedication to get as much power as possible out of the 996 Turbo engine. I already understood that cost is no real issue to you and I really envy you for being able to build your dream car.
    I've been told that titanium parts should be used only if the car is used during short period of times and with low mileage, for example during track racing. It seems that the Titanium parts are not that durable on a long run but are VERY effective during tough short term usage.

    The 996 Turbo engine makes a very good base for mods of any kind and the fact that a lot of performance parts are available originally from Porsche (although not made specifically for the 996 Turbo) make mods to it very attractive. However high cost is involved but I guess this doesn't matter to you.
    Most people I know who tuned their Turbos actually care a lot about cost. Some of them wanted to save a dollar or two and got severe problems with their tuning because they didn't listen to me or others warning them. It is no magic to get 1.2 bar out of the stock Turbo without modifying the chargers or somethig else but for how long will this engine/chargers run?!
    I'm also astound to learn about a 569 HP Tiptronic Turbo (NO mods at all on the Tip) who drove 60000 km(!) until the Tiptronic finally broke down. Not bad. Usually serious Tuners don't recommend pushing Tiptronic Turbos over 500 HP.

    I'm dying to hear about your final results. Maybe you could post a dyno printout?!

    Re: I have to admit that I admire your...

    RC, we should have a very interesting dyno run this coming Thursday. We changed the throttle body....it is currently 12 mm larger than stock. I was amazed when I discovered the 996tt uses the same TB as the Boxster. In addition to the larger TB we custom manufactured (enlarged) the black TB boost "Y" which leads to the TB. In addition we installed an air splitter in the plastic "T" which is behind the TB leading to the heads. After the dyno tests we are going to remove the motor and enlarge the tubes from the air box to the turbo's. In addition we are custom making intercoolers and enlarging the intercooler tubes. We have flow/heat tested the new intercoolers and they are 49+% more efficient than the stock 996tt ones. These intercoolers will require some under the fender body work.

    Hopefully the engineering will work.....either way I will let you know.

     
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