996 Engine Swap

Has anyone swapped a 3.6 Supercup engine in place of a 3.4 engine in a 1999 996 U.S. spec car? I am considering this swap so any info would be greatly appreciated.

Hi Craig - I saw your post...it's of interest to me as I am selling one of my 3.6 GT3 Supercup engines (<a href="http://mall.rennlist.com/scripts/featured/ads.cgi?db=race&website=&session_key=&search_and_display_db_button=on&re sults_format=long&db_id=73&query=retrieval" target="_blank">link to my ad</a>).... My understanding is that Technodyne in Arizona (Phoenix?) have done a number of these "conversions" -- you may want to contact them. - Nick

Thanks for the info. Does anyone have a telephone number for this shop?

<a href="http://www.technodyneracing.com/contact.htm" target="_blank">Technodyne web page</a> Chris Cervelli is the proprietor.

Can someone tell me how much $$$ to do such an endeavor with install and what is needed? Regards. Mike

I don't know everything that is required but I do know that you need to also have a GT3 transmission to use the GT3 engine in a 996. There are lots of other minor things like adding a third radiator, different power steering pump, different wiring harness, no PSM or traction control, different Motronic unit, etc. When you're done, you'll only be able to drive the car on a track, since the SuperCup engine has never been EPA certified in the US. You also need to have the engine rebuilt after a certain number of hours of use (PAG says 50 race hours but if you are just running in DEs you could probably get away with more). The rebuild will probably run you $20-30K each time, so you'd better put some money away for that. Quite frankly, if you want a track car, you're probably better off selling your 996 and buying a used SuperCup car. It will cost you less in the end than trying to do a conversion and you'll get all the other trick stuff like air jacks, fire system, center lock hubs, etc.

If you are trying to do a GT3 engine swap, I would recommend staying with the street engine unless you plan on tracking the car. I have been working on a GT3 conversion project for some time now and I have some info for those that are interested. One of the first things I'd like to point out is that it's not a simple engine swap. You need either a GT3 tranny or a 993 tranny. There are lots of other little things that you need to or should get including the DME, harness, misc hoses, new motor mounts, third middle radiator, shift linkage. Here are some prices: New GT3 engine w/DME, harness, etc. - $38-40k 993 tranny w/LSD - $4k GT3 tranny - ? not sure but remember being quoted $10-14k Misc parts - about $3-5k Labor for all this madness - about $5k If you go with a 993 tranny and shop around you can probably get the installation down just below $50k. You really have to start evaluating whether it's worth it to you, because by the time you finish the conversion, you could have made a very fast 996 turbo. Personally, I'm not a big fan of turbos and I had a chance to drive a GT3, so I'm hooked. Although I was planning on buying the engine new and using a 993 tranny, I managed to find a salvaged GT3 from Europe for a very good price. The motor, tranny, electronics, interior, suspension, brakes, etc. were all in good shape and it's been completely disassembled and is being air-freighted (minus the chassis) here to Los Angeles as I write this. It'll be another 4-6 weeks before the conversion is complete. I'll be posting a message with more information about the conversion at some point in the future.

kyopo, Considering the expense involved and the fact that when you're done with the swap you have a track only car, don't you think buying a used 996 Cup car for around $100K is a better deal? Karl

Your points about value vs. utility are well taken Karl.... Albeit illegal, my understanding is that not all of the converted 996/GT3 cup combination cars end up 100% on the track.... - Nick

Karl, If I wanted a track-only car, of course I would have just bought a cup car. Don't worry, once I'm done with the swap the car *will* be driven on the street. :^)

I appreciate all of the info posted thus far. The idea is to drive it on the track & the street so a cup car is not the answer for me. I already own a '01 twin turbo so what I am really looking for is a lightweight high powered rear drive burner.

Craig, If you are going to drive the car on the street, I think you want to try and find a new/used GT3 engine. Although not EPA certified in the US, I think you'll have a better chance of getting through an emissions test with this engine, since they are designed to be emissions legal in Europe. You also won't need to pull it out for a rebuild after every 50-100 hours. The SuperCup engines are race engines built to very tight tolerances and I think the headaches around emissions and rebuilding would quickly negate any performance benefit for street use. Karl

Hey Kyopo- How's the GT3 engine swap coming along? I'm very interested in your progress.

Hey Kyopo- How's the GT3 engine swap coming along? I'm very interested in your progress.

Craig, The engine swap is going. The GT3 engine, tranny and parts from a salvaged GT3 all landed and got through customs two weeks ago. We had some trouble getting it on an air flight before July 4 for obvious reasons. I dropped my car off today and the work has started. The tranny is being taken apart as I'm putting in a new R&P and gears, plus one of the shifter arms broke in transit so we needed to take it apart anyways. The tranny looks identical to the 996TT/GT2 tranny which makes sense since they all use the same motor. The stock R&P is 3.44 and the gearing is a little too tall for my tastes, since I'm never going to go 200MPH. I'm going with a 4.0 R&P and some shorter, close-ratio gears, although I made 1st gear a little taller. I'm making my stock 5th gear as the new 6th gear so my max speed will be about 155MPH. The brakes, suspension, saftey equipment, seats, wheels have already been installed. The aerokit is done and I've gone ahead and done a bunch of the small details including the gauges, handbrake, door sills, etc.. I'm also removing the sunroof on my car and replacing the rear bumper with a Euro-spec bumper (meaning no bumperettes). And I'll be polishing it all off with an '02 facelift and bi-xenons. After going through all the parts, we noticed some other minor details that are different between the regular 996 and the GT3 such as the glass panes for all the windows on the GT3 having serial numbers and the rear window has PORSCHE spelled out in black along the bottom. I'm going to try taking some digital pictures so I can document this project a little more than I have been doing. Anyways, I'm hoping in 2-3 months all the work will be finished and I'll be driving a (sort of) street-legal GT3.

Did you start with a C2 or C4 chassis? How did you make clearance for the oil tank and did you have trouble mounting engine?

[quote]Originally posted by kyopo: <strong>I'm hoping in 2-3 months all the work will be finished and I'll be driving a (sort of) street-legal GT3.</strong><hr></blockquote> Yes, please do take lots of photos and document what you are doing as much as possible. I too have been interested in swapping GT3 parts into a North American C2 or C4 as you are now doing. My thought was always to buy two running cars -- a C2 in the USA and a GT3 in Europe and then swap all differing parts between the two cars. Then sell the GT3 in Europe as a C2 and keep the C2 in the USA which would now be a GT3 in all senses but title. I take it that you will have a legal GT3 in the sense that you will keep the serial numbers from the original car and the Federal sticker on that car? I've always thought this the best way to proceed. How are you going about deleting the sun roof? I don't think you've specifically mentioned the suspension components. Will you swap all of this into your car? I think you will have one of the nicest 996's in North America when you are done! S.

[quote]Originally posted by kyopo: <strong>I'm making my stock 5th gear as the new 6th gear so my max speed will be about 155MPH.</strong><hr></blockquote> You might want to reconsider this. You are giving up more than 20 MPH at the top. The car is very stable at those speeds. With 6 gears you already have quite a bit of flexabiliy. Also, while you have the car apart you might want to look into adding the modifications to increase the brake cooling to the front brakes. This has always been a big problem on the front brakes of the GT3. S.

[quote]Did you start with a C2 or C4 chassis? How did you make clearance for the oil tank and did you have trouble mounting engine? <hr></blockquote> I started with a C2. Now I could be wrong about this, but from what I understand the GT3 uses the same tub as the 996 C2 and C4. The "chassis" components that people to refer to as differences between the GT3 and C2 are really suspension related. However, some of the later GT3 cup cars and RS models do use a different tub. The engine hasn't gone in yet. Currently the GT3 tranny is being redone with the new R&P and gears. The C2 is also being disassembled. So we aren't aware of any problems... yet. [quote]I take it that you will have a legal GT3 in the sense that you will keep the serial numbers from the original car and the Federal sticker on that car? I've always thought this the best way to proceed. <hr></blockquote> Exactly. :^) The way I did this was by finding a salvaged GT3 in Europe, having the car completely disassembled and shipped here w/o the chassis. [quote]How are you going about deleting the sun roof? <hr></blockquote> I'm switching out my front/rear glass shields with the GT3 ones (since they're different) and the GT3 wiring harness really has no provision for a sunroof anyways, so I'm going to swap out the roof panel and the headliner. It's not too hard. [quote]I don't think you've specifically mentioned the suspension components. Will you swap all of this into your car? <hr></blockquote> We've already installed a complete GT3 spec suspension and brake setup into my car and we have 3 good corners from the salvaged GT3. So, I think we're okay, unless you have some suggestions? [quote]You might want to reconsider this. You are giving up more than 20 MPH at the top. The car is very stable at those speeds. With 6 gears you already have quite a bit of flexabiliy. <hr></blockquote> The R&P and gears were carefully selected for what I had in mind. You're absolutely right, I am losing a lot on top speed, but I don't plan on going much over 155MPH even on the track. [quote]Also, while you have the car apart you might want to look into adding the modifications to increase the brake cooling to the front brakes. This has always been a big problem on the front brakes of the GT3. <hr></blockquote> Thanks for the tip. I'll have to ask my mechanic about it.

[quote]Originally posted by kyopo: <strong>"while you have the car apart you might want to look into adding the modifications to increase the brake cooling to the front brakes. This has always been a big problem on the front brakes of the GT3." Thanks for the tip. I'll have to ask my mechanic about it.</strong><hr></blockquote> If you seriously track the car then this is a must. In the short term you can probably resolve the overheating problem by going for harder and harder brake pads. But the result from this is hotter rotors and eventually cracked rotors. One alternative is to install bigger brakes. But this adds to the unsprung weight of the car. The more elegant solution is to improve the airflow to the front brakes. This was an original design problem with the GT3. There isn't enough cooling air. I don't own a GT3 but I'm told by my friends who do that this modification is sufficient for even track use. It is a common modification in Europe. Thanx for all of the great info! Please keep it coming. S.

I have completed a GT3 conversion. Anyone needing information on this can email me.

The reason I asked the above question about the oil tank and engine mount is because my factory literature indicates that the sheet metal in front of the engine and behind it has been changed to acccomodate the GT3 engine. This is because of the engine mounted oil tank and the differing rear engine mount. When I look these parts up in my fiche I come up with a drawing but "part number unknown" descriptor. Also the literature states that all the GT3's are based on a C4 tub. <img src="graemlins/yltype.gif" border="0" alt="[typing]" />

[quote]Originally posted by Cupcar: <strong>The reason I asked the above question about the oil tank and engine mount is because my factory literature indicates that the sheet metal in front of the engine and behind it has been changed to acccomodate the GT3 engine. This is because of the engine mounted oil tank and the differing rear engine mount. When I look these parts up in my fiche I come up with a drawing but "part number unknown" descriptor. Also the literature states that all the GT3's are based on a C4 tub.</strong><hr></blockquote> You are correct. The front section of the GT3 is identical to the Carrera 4's. This, because the C4 has a reinforced front tub which was beneficial to the GT3. The rear panel, however, is different from the Carrera and Carrera 4. This part is shared with the Turbo and GT2 as well.

Kyopo, What is the status on your GT3 conversion ??? S.

Updated status of GT3 conversion: These projects always take more time than one expects. Here's a list of what's done and what's not. - Brakes and suspension have been done for awhile. - GT3 seats already in. Harnesses not yet installed. - Salvaged engine needed some cooling lines, misc hoses. Done. - 4.0 R&P, custom gears installed in tranny. - Front end completely finished including third radiator. - Wiring harness is done. - ECU was actually missing in the package but was later shipped and received along with some other electronics. - GT3 RS black rollcage from Matter arrived and is awaiting installation. I currently have the rollbar with cross brace, but will pull that out as I'm doing a full interior leather conversion. Then the rollcage goes in. - Sunroof delete. Roof panel and headliner ordered. The GT3 wiring harness doesn't provide for a sunroof anyways. - '02 xenon headlight conversion. Headlights ordered and received. Front fenders received. Front '02 GT3 cup bumper received (has some interesting vent holes on the top and a tow hook slit on the right? side, not sure if I'll keep the holes or not). - Rear bumperettes removed and rear bumper cover bumperette holes fixed and repainted. So far not bad. The whole project is on hold until we acquire one of the shifter arms for the tranny that is unique to the GT3/GT2. This item broke during freighting the tranny over to the US. And unfortunately it doesn't have a part no. in the PET program and can only be ordered by Porsche Motorsport customers. We're supposedly getting this in any day now, but we've gotten the wrong part 2 times in the past. Maybe we'll get lucky this third time around. Once the shifter arm is repaired, the project is about 2-3 days mechanically from being finished. Then I need to get all the electronics including ECU, ignition, door locks, alarms "re-keyed" with the same signature. Hopefully, by then the full leather interior will be available, I can put that in, install the rollcage, put on the '02 fenders and headlights, repaint as needed and I am done. If I'm lucky, maybe I can have a driveable car before Thanksgiving and get all the cosmetics worked out before Christmas. I have some photos of the engine and car completely taken apart, but I've been too busy to post them. Will do so when I'm back in the states. I'll have another update hopefully soon.

Thank you Kyopo! As you can see, I haven't forgotten about your conversion. I really appreciate the update. I shall also be watching for the photos once you have the time to upload them somewhere. Happy GT3'ing! S.

[quote]Originally posted by kyopo: <strong> Front '02 GT3 cup bumper received (has some interesting vent holes on the top and a tow hook slit on the right? side, not sure if I'll keep the holes or not). </strong><hr></blockquote> The GT3 brakes are known for cooling problems when used hard on the track. Maybe you could use these vent holes for scoops to cool the brakes? In Europe some of the shops will add additional air cooling for the front brakes to solve rotor cracking problems. So maybe this would be a nice addition to add to prevent the problem? S.

Interesting... a couple questions and thoughts... 1. If you put ont he 02 nose, what are you doing for body work? The GT3 aero kit will not fit. 2. The C2 vs C4 tub is interesting as it may be the difference in the X74 in europe. Anyone know how to tell the difference? 3. It sounds like you are installing a street GT3 engine, not a cup car engine, is that correct? 4. Are you sticking with the stock supension and exhaust, etc. or going for better aftermarket solutions in some cases?

[quote]Originally posted by FixedWing: <strong> The GT3 brakes are known for cooling problems when used hard on the track. Maybe you could use these vent holes for scoops to cool the brakes? In Europe some of the shops will add additional air cooling for the front brakes to solve rotor cracking problems. So maybe this would be a nice addition to add to prevent the problem? S.</strong><hr></blockquote> I am going to look into this with my mechanic. I've heard a lot about the brake cooling issues. Thanks for the tip.

[quote]Originally posted by Ed Newman: <strong>Interesting... a couple questions and thoughts... 1. If you put ont he 02 nose, what are you doing for body work? The GT3 aero kit will not fit. 2. The C2 vs C4 tub is interesting as it may be the difference in the X74 in europe. Anyone know how to tell the difference? 3. It sounds like you are installing a street GT3 engine, not a cup car engine, is that correct? 4. Are you sticking with the stock supension and exhaust, etc. or going for better aftermarket solutions in some cases?</strong><hr></blockquote> 1. I have the '02 style GT3 cup bumper from Porsche Motorsports. I don't think there's an issue with the rest of the aerokit fitting. 2. Don't know. Sorry. :^\ 3. Yes, it was an '01 GT3 street engine with about 2,000km. The cup engine was too much for me to deal with in terms of rebuilds, etc. 4. I've already put in a full GT3 cup spec suspension in the car before the conversion started. The car is *extremely* low, the ride is pretty harsh for the street, but the tires do not rub and there is very little body roll. It's very tight and feels absoluetely wonderful in the twisties. We have the stock GT3 exhaust but I might slap on an aftermarket one. I'd like to drive the car around first. It's been in the shop since July. I almost forgot that I had the car. :^)