Does a Turbo bumper really work on a Carrera / how to make it work?

The Turbo bumper, like the aerokit/GT3 bumper, gives you almost no front end lift. But it’s much less likely to get banged up by speedbumps, driveways, and perpendicular parking, because it isn’t quite as low in the front, and bexause the lowest part is a rubber spoiler which I presume is flexible, and not too hard to replace. The problem is that it is designed to accommodate slightly larger radiators and air conditioninng condensors, as used on the C4S and the 40th AE. So I’m wondering what happens if one uses it on a regular Carrera. Where does the air that would have flowed where the C4S radiator extends beyond the Carrera’s? Does it end up causing a lot more drag or lift? Do the Carrera radiators get less air because the standard bumper would direct some of that air to them, but now it’s lost? Or does the radiator surround or something else make sure all the air ends up in the same place anyway? If just bolting a Turbo bumper on doesn’t work for such reasons, is there any solution? Alternately, does anyone make a Turbo style bumper for Carreras with the radiator intakes modified so the air gets to the right place? Any insight into this would be greatly appreciated!

I would think the bigger problem is the C4S/Turbo bumper is for WB cars, and would not line up with NB cars.

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Agree...if he were asking about the rear but I believe his question is about the front - no wide body difference there.

b3freak just did this mod to his Mk2 cab, maybe he can halp.

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I did not know that - good info!

Just throwing in a link to a previous thread and car with this transplant. I'm interested in this question also. https://rennlist.com/forums/996-foru...arga-pics.html

I have a turbo bumper on my 996.2 targa. I've never had any overheating concerns and I run it pretty hard at a local track. Although my oil pressure does drop significantly when it is hot which implies the engine gets pretty warm. I wouldn't be concerned at all with the turbo bumper for street driving. For track driving it still seems to be okay and you could always install a third radiator when you do the swap.

Changed out my base bumper with a Turbo Front bumper but decided to keep the original duct work in order to funnel the air (i.e. split) through the front vent into the rads. I was ready to purchase the newer C4S duct work, but the temps stayed right at 180F with no problem with overheating. My only concern is that some air may be getting trapped above the base duct work, but so far no issues.

My experience is with a 996 Turbo the front bumper/air dam is quite low and scrapes almost every where. The part which hangs down the most is the air dam and it is not real flexible. If one is not careful entring/leaving driveways and not pulling too far into a parking space it can break. A new Porsche air dam is several hundred dollars. There are less expensive ones avaiable but I know nothing about how they fit, their quality, etc.

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Actually, the TT/C4S bumper has a slightly lower ground clearance than the base bumper, but because it uses a black front lip spoiler, those can be changed out easily when damaged. As you see from my pictures, the air ducts are smaller and customized for the base bumper. But remember, the rads have rear fans and act like vacuums that suck air through the duct work. If you get the larger C4S duct work, they won't fit the smaller rads of the Carrera and so you're back to square one. As mentioned before, I decided to keep the original base duct work because of the center spitter. It acts as a splitter and forces air to the left and right. I haven't seen a problem with temps... the cars still stays at 180F unless I'm racing it around the mountains on a hot day. IMHO, I've found the Turbo bumper to minimize lift had higher speeds compared to the base bumper. (that's a non-scientific opinion) ha! Remember the air flow passes through the radiator and into lower portion of the fender well. If you're seriously concerned about air flow, drag, etc, then you may want to upgrade to the GT3 aero bumper with center vent. But you'll spend more than $5,000 on the bumper, duct work, paint, and trim details. Lots of Aftermarket bumpers for sale on eBay. But some of them look weird and cheap. And, if you're tracking the car, they won't funnel the air properly... they're usually designed for looks over performance. Proper cooling is paramount for tracking these cars without serious damage to the engine. Again, there are many "turbo like" aftermarket front bumpers, but I would recommend you stick with OEM. If airflow is your top priority, then purchase GT3 aero bumper, but if you want the Turbo look, then you can be safe with a OEM turbo/C4S front bumper. They are pricey, but you still find a complete setup on eBay for under $1000 if you're patient. Most come without the center and side vents, but I was patient and found one in Florida for $400 complete. Let me know if I can help further.

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Absolutely right! Do you realize that Porsche charges $150 - $200 each for the front black vents on the Turbo bumper? Simple piece of plastic that didn't cost 25 cents to make. ha! Now on the other hand, if the OP doesn't have a Carrera C4 tip, then more than likely he doesn't have the center radiator; therefore, he won't need the center air dam than funnel air below the car. Maybe the OP can post some pictures.

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The air dam is intended to restrict air from getting under the car. This creates a high pressure area just ahead of the car at the radiator intakes and a low pressure area under the car. This high pressure ahead of the radiators and low pressure behind helps air flow through the radiators. It also helps keep the car stable at speed and helps draw air through the louvered engine compartment lid to help keep that cool. And last but not least has a low pressure area at the back of the car to help air flow through the turbo intercooler vents one on either side of the car. This air dam (and the other aerodynamic aids of the Turbo) works very welll as my experience with my Turbo is it can maintain a very stable and reasonable coolant temperature even when operating in extreme ambient temperatures, even with just one radiator fan working.

Or locate a wrecked turbo that's being parted out.

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Hey Mac, can you post a picture or part number of the center air dam that you reference? I would like to reference it to the OEM parts break down. Porsche tends to use several names for the same thing. Are you talking about the front lip spoiler - part number# 9965055550201C

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Stock "before" looks much better. "After" looks like Tom Jones stuffing sweat socks in his jockey shorts.

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John 1 B3freak 0 B3 - your serve...

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"Hey John, I resemble that remark!!!", shouts Tom Jones.

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Touch�! John you don't have leg to stand on. (snicker) Who's the lady friend!?

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John 1 B3 displays "Depends picture" John walks off court with face covered in shame match forfeited by john Game, match, B3 wins Yay!

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I can live with my stock, Carrera, manual transmission, bumper's looks. It's growing on me, in fact. But really, "after" looks like a 177mph sports car. Not a shouty one, but a serious one. "Before" looks electric. Also, as photographed, from a low angle with bright sunlight, the contrasting black grills contrast a bit strongly with the bright silver car. As seen normally, this contract will be less, especially when the black bits are a bit dustier. I like how 996 Carreras look. Many do not. Almost all, however, regard the C4S as the most beautiful 996, and the bumper is a big part of it. But never mind, both look good enough. It's how the car drives that matters.

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This is a C4S lip spoiler. The Turbo lip spoiler is equally deep all the way across. And I think it does not have those two vents in it.

The 40th AE 996 has the "turbo' bumper and i think it looks waaay better than the stock bumper. Also the air grills by the radiators are larger and let more air in so cooling would not be a problem. b3freak - i think your car looks great with it's new turbo bumper - well done.

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Thanks for the info and advice! Sounds like I shouldn't be concerned this would cause heat issues. But on track, can you feel the reduced lift? And has it had any impact on your top speed at the end of the main straight? (Not that you'd notive a speed difference while driving, I suppose, but if you have a data logger ... .) (Of course, it won't have a big impact on top speed at most tracks, unless it completely messed up the aero. But a 1/2 mph difference around 130 mph can be a much bigger difference at vmax. And since I have autobahns handy ... .)

b3freak, thanks for the helpful info and photos! Looking at the photos, it's clear the main difference between the shapes and locations of the openings in the bumper itself are that the turbo's oppenings are much higher at the top. Suprisingly so as the radiators are only sligtly bigger. Do you know if the duct that leads to the radiator on the Turbo or C4S extends as high as the openings in the bumper? Or if not, do you know how much higher it extenda that the regular Carrera's duct? Thanks again!

2003 C4S front without bumper DSCN1898_zpsos6bddg2.jpg

turbo bumper on a non turbo car is more rice than uncle ben! haha J/K

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I was actually thing this. I could see if one is going to put in the 3rd radiator, but putting the turbo bumper on just for kicks is kinda fake poser-ish. Hell why not put the turbo badge on it too?

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Ha! "more rice than uncle ben"... funny!!! Seriously, you know Porsche put the *same* turbo front bumper on the Carrera C4S and 40th AE at the factory, right? Plus, Porsche sells many OEM aero bumpers for the 996 "non-turbo" cars. I'm not for making "tribute" or "replica" cars, but there are many options (e.g. Aero Side Skirts) that really make the car look aggressive. IMO. In fact, Porsche will gladly sell Carrera owners a complete GT3 aero package and smile when receiving the cash. ha! Cheers!

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As I stated to Neto, this is not the same as building a "tribute" or "replica" car because the same *turbo* bumper was put on the C4S and 40th AE NB car. Porsche also provides several GT3 type aero bumpers to convert your base Carrera into a more "racer style" car. However, I've seen many that converted base Carreras into turbo looking cars and even attempted to sell them as such. Therefore, sellers need to do their homework. But upgrading to different bumpers is not the Folex syndrome IMHO. (forgive the watch analogy) I didn't badge it up as a Turbo, GT3, or C4S. My car clearly says "Carrera" on the back. I've also kept the base bumper and even the horrible Becker stereo that came with the car. I'll gladly hand it over to the next owner along with the official COA.

Took my car to the Blueridge mountains for a major thrill ride. If you live in eastern US, a day on these mountain roads must be on your bucket list!

^^Looks good!

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Really, does my first post, or any of my other posts, suggest that the reasons I would oonsider this are aesthetic? If you weren't already aware that there are potential benefits other than adding a third radiator (which doesn't require a turbo bumper, by the way), see above. And yes, putting anything on just for kicks may be kind of fake poser-ish, but if this is the right comment, it's the wrong thread. Really, these knee-jerk, unthought-out criticisms get tiring. If I wanted that, I wouldn't be discussing lift and drag on the forum when I could just discuss it with my wife ...

I love the different bumper options. Just my opinion, but the stock c2 bumper just lacks the aggressive appearance that the car deserves. And when the turbo bumper is combined with aero lower rockers, it completely changes the attitude of the car into something that almost looks as though it's in motion when the car is sitting still. And unlike aftermarket options, you know that Porsche spent time with it in their wind tunnel. This swap is now on my to-do list. The rear bumper with the two carbuncles surrounding the license plate is also something that needs to be cleaned-up. The bummer will be matching 17 year old ocean metallic blue correctly.

So we now have some excellent, helpful photos in the thread. Thanks b3 and fierofly! Looking at he C4S photo, it seems clear that the ducts go much higher. If you put the turbo bumper onto a car with Carrera ducts, a lot of air must go rushing in above the radiator duct. Where does it go? On both cars, there is a cavity above the radiator duct. Does anyone know if it leads somewhere? If not, and possibly even if so, then it can't do much good aerodynamically. But on the other hand, once there's enough air pressure in there, it might keep additional air out just as well as if it were closed off. Might ... . Either way, a lot of people here and elsewhere have reported increased front end stability. So far, so good. But what about drag? I know that there aren't too many users of this forum who have a chance to vmax their cars often enough to test this. Nor is it likely many have done a coast down test from a somewhat lower speed with a data logger. But if anyone has any insight into this ... .

And there remains the question whether anyone makes a quality immitation of the Turbo bumper, but with some modification so that either all that air makes it to the radiators, or it never enters the bumper's openings to begin with. I know Ruf makes semething that looks Turbo-ish. And I'm pretty they tested in enough to be sure it's OK aerodynamically. But I don't think it's as close to a direct copy as what I have in mind. I'm also pretty sure it wasn't wind-tunnel tested. Possibly a (copy of a) 997 bumper would do the trick. I'm pretty sure RPM Technik in the UK is putting these on 996s. And come to think of it, it's hard to say whether the Ruf bumper is more like a 996 Turbo or a 997 Carrera. (As may or may not have been clear from my first post, the simplest way to get a good result in terms of drag and lift without depriving the radiators of air is to use an aerokit bumper. But that's got to be a disaster for speed bumps, perpendicular parking, etc. The leading edge is lower than the turbo's, much less Carrera's. And it's not a seperate lip spoiler. It's the bumper itself. So one small impact and you need to replace the whole thing :-( )

RUF does offer the RTurbo front bumper or NB cars. Only for 2002+ cars though.

Here's the GT2 which the stock bumper similar to the RUF that AMGSiR posted. You see notable differences. The GT2 aero bumper kit is expensive, but can be purchased directly from Porsche. You'll need to be ready to purchase the center air duct work (see picture of air movement through the center vent), but with the absence of the center rad, piecing it together will be a challenge.

https://www.amazon.com/1999-2001-Por...sche+body+kits

For various reasons, they are probably not for me. Probably too much lift reduction/downforce, with those big splitters, so that I'd need a GT2 rear wing, which I don't want. Though there is big question of aero impact without a 3rd radiator. There's the question whether the Amazon bumper, from an unknown (to me) brand is any good. Also seems their lower lip/splitter shape doesn't match the GT2's, though hard to be sure. There's still the question whether they deal with the problem that a turbo bumpers openings are wider than the Carrera's ducts. And re. the Ruf, that looks like it would get banged up even more quickly than an aerokit - though perhaps it's not as low at the leading edge? Anyway, much better to have a replaceable and hopefully more flexible lip/splitter, as on the GT2 and the turbo. (My understanding is that while splitters can contribute signifcant downforce versus air dams, there's a corresponding drag penelty for that downforce benefit, whereas air dams typically negate lift with little/no drag penalty. Since I'd be satisfied with the turbo's level of lift and would like to avoid extra drag, something more turbo shaped would be better for me than the Ruf or a GT2 immitation.)

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The bumper on the Amazon listing is manufactured by the Duraflex. They're well known in the industry for manufacturing high quality aftermarket bumpers and other body panels. They would be on my list if I'd consider an aftermarket alternative to OEM. http://www.duraflexaero.com

This is a great deal on Porsche bumpers. If you notice in the craigslist picture, the owner has a turbo bumper in the background. If it includes the grilles, this would be a stomping' great deal. http://atlanta.craigslist.org/nat/pts/5922616069.html

b3freak, you mentioned considering using Turbo ducts. Did you check prices, and if so, could you give us an idea of the costs? Thanks!

Right side - 99657532202 - $260.00 Left side - 99657532102 - $207.35 Here's the part break out:

Thanks! If it were just that, and if one could find a used set, it would not be so bad. But I checked some of the other parts, thinking that perhaps if the Turbo or C4S or 40AE use some of the same parts as Carreras, then this might work even without Turbo radiators. Alas, all the big parts on a Turbo, C4S and 40AE are different from those on a Carrera, so it doesn't look good :-(

Or am I missing something? Did you think the Turbo vents might work without replacing most/all of the other bits? Thanks again!

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I finally figured something out which I guess, b3freak, you had already mentioned early on. If one add turbo ducts, the air that enters the bumper in the middle of the car has nowhere to go unless one has a third radiator - as seen in this photo. However, 40AEs and C4Ss do not have a third radiator as standard equipment, so I guess if one wants to invest in lots of C4S or 40AE parts, this would not be a problem.

One important note... The center grilles for the Turbo and C4S/40th AE are different. Since the Turbo has the center radiator as stock, the center grille has a open vent design, but the C4S/40th AE has a more restrictive center grille that works more like a dam than a vent. (see pictures)

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Thanks! That helps make the overall picture pretty clear/complete. And there�s still no sign of any way to get (almost) exact C4S/40AE aerodynamics except to use every single part between the bumper and the radiator exit vents. It seems frustratingly close though. With the just the C4S bumper, center grill, and side radiator intake ducts, if you could attach the intake ducts to the Carrera radiators, it would be (almost) the same. There are two potential obstacles to attaching them. One, the exit end of the intake ducts may be too large. But the C4S radiators are only ~8% larger. If the exit end of the intake ducts is also 8% larger, where would that extra air go? If it would just go through the a/c condensors, it�s probably OK. If it would completely pass the the radiator and condensors on one side or above or below it might still be fine, but on the other hand, it might completely change the air flow after the radiators and condensors � . The second obstacle is that it looks like the intake ducts attach to the radiators with screws, and if the holes are not in the same place � . I assume it doesn�t miraculously happen that the C4S intake ducts connects well with the Carrera radiator. (Does anyone know?) Assuming no, the best solution short of replacing everything would be if some aftermarket supplier of immitation Turbo/C4S bumpers also supplied an intake duct shaped like the C4S intake at the front, and the Carrera intake at the back. Don�t supose anyone knows of such an intake duct?

As b3freak pointed out to me these Turbo bumpers will not fit our MK1 cars so options are limited for a change.

^^Yep, you'll have to either go with an aftermarket bumper or the OEM Aero bumper, but the Turbo front bumper is not compatible with the Mk1 front light enclosures.

Learned something new: I talked to a vendor that sells genuine turbo bumpers as well as imitations. They say that you should cut away the top part of the Carrera duct so that the air that enters above it can still go into it. They added that any good body shop shoulld be able to do it. Alas they don't have photos. And although there are very helpful photos on this thread, it's nonetheless hard to envision how that would look. (And somehow, I'm not very tempted to have my bumper removed just to look at it ... .)

Actually, that's pretty good advice. I was thinking about trimming my duct work to minimize air getting trapped at the top of radiator. If you look closely at the picture of my duct work, you'll noticed a lighter black section and the back being darker. The lighter section is rubbery and would be easy to cut off. But as mentioned before, my car hasn't had any trouble maintaining the proper temp of 180F. I'm sure if you pushed the car really hard, the added air flow would be needed. My last trip to the mountains was very spirited to say the least and the car stayed cool the whole time. I wonder how it will be affected by summer temps? We'll see.

Pretty sure there is a fan at the back pulling the air thru and away form the radiators so i don't think any air would be trapped. The radiators don't have any problem cooling the engine down when the waters flowing thru them and your moving. After reading Hartech's info about these cars i would personally install a LTT ( low temp thermostat) - as that will get the water flowing earlier. It seems well documented that the Temp Stat is not the greatest at relaying the info as it's happening - i.e. your engine is a lot hotter than it says ( especially if your doing spirited driving).

Slilghtly off topic, but I don't suppose anyone knows how much a Turbo bumper weighs (whether with or without the grills)? Or any other 996 bumper, for that matter?

I believe it's around 20 lbs without the grilles and lip spoiler.

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There are fans behind the rads to pull air through the duct work, through the radiators, and forced out below the car. But the fan enclosures are form fitted for best performance; therefore, air that travels through the front vents and above the Carrera base duct work could get trapped and that's why it's best to use the correct Turbo/C4S duct work when using the Turbo front bumper.

yes the T/c4s has a bigger duct for the bigger intake.

^^ and, because of the slightly bigger rads too. ;-)

Check this thread out RS10! https://rennlist.com/forums/rennlist...ale-996-a.html

I did the conversion on my old 996.2 narrow body-- my car served both as a commuter car in stop and go traffic and occasionally on the track at New Hampshire motor speedway My conversion involved sourcing a Turbo bumper cover and ducting as my C4 had a center third radiator. I also used a C4S lower lip chin because the turbo lip is meant to work with the rear Turbo wing. The body shop had to fabricate a way to make the underside mount points match up. I spent $1900 on the conversion with painting,labor and found the car was far more stable both on highway and on the track and there was no change in cooling. There were maybe 3 times in 4 yrs that I encountered any scraping of the lip - clearance was fine and the car looks waaaaaay better

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Hey Man, we miss you around here... when are you going to buy another 996 and rejoin the fold?

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i can only say this as a warning to all current owners: do not sell your 996. At this age if it's still running it's likely to last for the next 30 yrs. everything on today's cars are electronic and forced induction to meet emission and fuel consumption standards. it is the last of the true 911s i regret selling mine

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Man, I'm not trying to rub salt in your womb, but dude, you had a beautiful 996 especially with the TT bumper upgrade. Seriously though, don't wait too long, find you a deal on another cab or coupe while the prices are low and while supply is still high. I've already started to notice dealers increasing their asking prices. But a Mk2 996 with low miles can still be snagged for less than $25K if you're patient.

Another interesting thing which I recently learned: Apparently Ruf makes their own ducts to be used with their bumpers. No pictures on their website, alas ... .

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I realized I was probably mistaken about this. According to the PET, the 40AE does have a third (central) radiator, as well as a different center grill, and a special air duct behind it (which strangely, no other cars in the normal 996 PET (which I think excludes all Turbo and GT cars) with a central radiator seem to have). So on the one hand, if you want to do a narrow body Turbo/C4S style bumper conversion exactly the way Porsche did it, you get all the 40AE bits, including the central radiator. But if you want to save money, you can get pretty much the same result by using all C4S bits. (To be clear, this is then a C4S conversion, not a Turbo conversion, with differences including the spoiler, and the Turbo's central radiator and associated parts.)

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Roadsession, if you are still visitng these parts, when you said your body shop had to fabricate a way to make the underside mount points match up, did this involve modifying the ducts so they sent the air where it's needed and not where it isn't? And if so, can you share any details, photos, etc., re. how they did that? Thanks!!

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The turbo bumper does not extend far enough to hit the stock mounting points on the underside of the narrow body tub - has nothing to do with the ducts. I cut the section out of the stock C2 bumper and used it to bridge the gap left when the turbo bumpers installed. This bottom section of the C2 bumper does have the vents where air would exit should the center rad be installed. I did not have a center rad so I made a block off for the turbo center rad opening. The stock C2 rads worked fine under my turbo bumper. ETA... I saw your other thread about venting the fender liners... been there too. Speaking from experience here.

I just installed a TT bumper on my Carrera� The jury is still out on the look.

I think it looks good, not the oem classic 996.2 look, but it does look good. Just make sure the correct air ducts & radiators all line up correctly for correct air flow. That can be a big problem with not oem bumpers. jmo

Do you need Turbo radiators for effective cooling with the Turbo bumper & shrouds? Or can the regular C2 rads be used without any cooling issues?

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Not sure, I do know my oem bumper 996.1 & 996.2, with oem air ducts, oem style radiators, all line up perfect. The air ducts plug right in to the bumper making it a pressure vessel at speed, flowing directly into the rads. Also know there is a lot of different bumpers, needing different size ducts, and some cars have different size radiators needing there own ducting and rads. IIRR Jake or Charles, noted how many engine rebuilds he's done on aftermarket/mismatched bumpers/ducts/rads, and went on to explain it... Guess my point was, this is an important aspect of the bumper system on 996. Maybe much more so than the 'look'... jmo

Right on, I read that too and am concerned about destroying the cooling ability on our cars. Sure seems like an expensive experiment, especially if the results are worse than the stock option.

I ran the turbo bumper with C2 rad ducts and noticed no difference in cooling during track use. The C2 rad ducts are undersize for the turbo bumper openings so there is no, or very little impact to airflow into the duct. It looks a bit wonky but no measurable performance change.

You could piece together an exactly fitting combo by using the ducting of the 40th anniversary model. That has the turbo bumper combined with AFAIK 996.2 carrera radiators and ducting.

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Golden idea, man! Thank you!!

Yup - my 40AE came with the Turbo bumper and the Turbo rads. They are quite a bit larger and provide more cooling capacity than regular C2 ones. I ended up adding a center radiator as well but had to make my own connection fittings as the available kit will NOT work on a 40AE, but might on a regular C2.

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Not for nothing, with all due respect... but didn't you blow up your c2 on the track...?

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No, I didn�t. Sounded great when I took it out and performed about a 1/3 as well, that wasn�t an engine health issue just an inherent one to the M96.

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Ok, thought I remembered something like that. But now all m96 problems are just a distant memory for you, with your new awesome dry sump LS 472(?) WHP. I'll probably copy that but make it a street set up when one of my m99 let go... Always wondered how a LS 996 would handle out on the track...?

Ok, new to the 996 world. Have purchased a 2000 C2 and just waiting on it to be picked up and brought down to me. Is it still the case that only the GT3 bumpers, OEM-wise, will fit this car? What about the Duraflex options? Are they solid, or do they vibrate and flop around like a 16 year old's ricer when driving down the highway at speed? I personally think the GT-2 front from Duraflex is the best looking front bumper, but will stick to OEM if there are no good aftermarket options.