BrockPorsche

Silly question, but out of curiosity anyone have any idea how this SC affects one's gas mileage?

AllanJ

You're right - it is a silly question.

I couldn't tell you for sure, but for a rough comparison check out the mileage of the MB SLK320 vs the SLK32 AMG. Both 3.2L engines, one NA and the other supercharged.

2003 SLK 320 - 20/26 (city/hwy)
2003 SLK 32AMG - 17/22 (city/hwy)

Ballpark 15% reduction with the supercharger.

BrockPorsche

That concurs with other numbers I've managed to find since making that post.

Thanks

Porsche_Smile

it drops.... but the problem is when you get the sc..... you tend to floor it more often so your gas goes down really fast.......

Oscypek

yeah kind of off but on topic at the same time... my car has 112k miles and the engine is leaking oil and according to euroquip and motorwerks a new engine is all i can do to fix it... well ive been adding oil once a month and the thing isn't leaking that bad.... i was thinking would it be bad if i got a supercharger hope the engine lasts me about a year with the supercharger (need to get some more cash that why i need a year) and then just get a new engine and but the supercharger in on the new engine... im just thinking will my car hold up long enough for me to be able to get the funds i need for the new engine... i should just get the engine and then the supercharger but I WANT IT NOW!!!!

Bucket_hat_Loren

Perhaps also a silly question: Is it OK to install in a cab? Does the increase in bhp and torque create any body flex issues or anything like that given the lack of a top?

TheSpeedDemon

Hmmm...new thread for me and I read through it thoroughly.

Having run S/C's on my 89 Mustang for many years now, I know how important the CARB certification is. It is such a pain in the **** to get through smog if you don't have the exemptions so you end-up having to remove shyte every other year. On a 5.0/5.8 removing a S/C kit is easy, but on a Porsche I do not see it being so.

But after going through the links to Evo and reading up on the S/C kit, I have the following questions/comments:

1. This is a Vortech S/C and Vortech makes a lot of CARB S/C's (head units and kits). So why isn't Vortech pushing the point to DMV along with Evo (unless they are)? Vortech has a chance to come out as a winner if they do. I visited Vortechs site and saw no mention of a kit for a Porsche. Also Evo mentions a V2, is this the old V2 or the new V2 SQ and if so what trim?

2. Maybe the answer to question 1 is that it is not the S/C but the 6-High Flow Bosch Fuel Injectors that is causing an issue? So maybe the head unit passes but the injectors at idle fail? Too many questions until the CARB is put on the head unit.

3. There is no mention of what boost this kit puts out? Too much boost will reduce the life time of the engine. Not sure what the compression is on the Porsche 3.4L, but with a S/C you want to be around 9.0:1 (or even lower - my Mustang is at 8.5). Remember S/C's put more air into the cylinder, and so 8.5:1 with 12lbs of boost is like 13.0:1 or more, so head gaskets, head studs etc. are pushed to the limit.

4. Can you change the pulley to get more or less boost?

5. Serpentine belts have a tendency to slip even with it tight, so does it come with a cog belt setup? This is what I run on my Mustang, no slippage but you do get a different sound from the S/C like a gear drive unit as the air is moved around by the ribs in the belt, some like it some don't, but when you are at a stop sign and someone hears it clearly, then they know you are serious

I know a lot of questions, but things that I have learned over the years running S/C's on the street. I will not be getting one for my Porsche, I do not want to hassle with smog laws and additional wear and tear on the engine and other components. Oh yes, S/C's produce power, lots of it and it is a lot of fun, but they also produce lots of heat and additonal wear and tear on the engine. If the engine is stock you have to be easy on it.

So I know some of you will go for the S/C and you will enjoy it, but if you are about to add a $10K upgrade to the engine (a bolt-on), then do your homework first, as it is a differnt world when you go S/C's.

So that's my 2 cents on this thread.

Chuck Jones

SpeedDemon: You make some very valid and relevant points. It all comes back to your Point #1. There's definitely a fairly substantial market share waiting if they'd get the CARB problem out of the way.

1999Porsche911

Lowering the static compression ratio of a boosted car is not necessary with currently available fuels, knock sensors and timing controls and intake heat controls. Lower compression ratio and high boost levels have their pros and cons as do higher compression ratios with lower boost levels do.

The standard EVO SC setup delivers approximately 5 - 6 psi on the 11.3:1 static compression engine which translates into a dynamic compression ratio of more than 15:1. This is substantially less that the 3.4 engine can handle, as far as pressure goes. You can safely set it up to run in excess f 18:1 dynamic compression ratio. The boost limit is dictated by efficiency and not componant strength.

Biggest advantage of maintaining a higher static compression is street driveability off boost. You do not have the lag resulting from a lower hp engine off boost.

You are mistaken to state that an engine with an 8.5:1 compression ratio supplied with 12 psi of boost translates into only around a 13:1 compression ratio. It is considerably higher than that....more like 15.4:1.

Belt slippage is not an issue for boost under 10 psi.

As far as durablity, maintaining proper heat levels and running the correct oil minimizes any additional wear to the engine.

TheSpeedDemon

Chuck, absolutely a great chance for Vortech. Evo maybe the first to make the kit but others will follow along shortly afterwards once the CARB is done (this happened in the early 90's with the Mustang 5.0 and S/C kits. The after market industry is huge for the Mustang, SEMA was flooded with stuff in those days primarily everyone concentrating on the 5.0. Today with the new Mustang it continues).

With early 996's becoming more available at prices that more people can afford, they are falling into the hands of thoughs that want to push the boundaries with this car in regards to mods. For a horse power junkie to pickup a 996 say for $25K and to dump another $15K into it with suspension and power mods, gives them a beast on the road for $40K (rough estimates OK). But yes here in California without the CARB, this possiblity will only be had for those that want to play the smog game every other year. Side note, these power horse junkies are the type that do not mind rebuilding the engine every winter to maintain the power on the road for the upcoming summer.

Going back to the 90's, it was a lot easier to get S/C's through the CARB system as standards were not as stringent as they are now. So trying to get a S/C kit through is probably going to be very tough with all this 'green' talk going on. It won't be a porblem in a few years when 99 becomes the year that smog is no longer needed on such old cars, but most of the people that want this power cannot wait that long.

TheSpeedDemon

Great feedback and much appreciated as it tells me more about the Porsche engine. Like I said I am not familiar with it and I did not have my stats next to me regarding my setup. I shot of the hip a bit but I wanted to get my 2 cents in. My main point was that in California without CARB on the S/C you are taking a gamble. See a few of my friends cars towed from the checkpoints they do here...not a pretty site.

TheSpeedDemon

BTW...this is from Evo website about the group buy:

The group buy is effective from March 5th, 2007 - March 19th, 2007

GunKata

I'm still waiting to see more people post up about their experiences with this kit. I've asked around and no on really comes forward. I also am not happy about the "Porsche Tax" of a kit like this, when similiar parts for Japanese cars run $3-$5K tops -with all parts (injectors, ECU mapping/system, turbo, etc.).

Makes me consider if I should keep my car and eventually SC it, or just wait a bit and shoot for a 996TT or go grab an Elise and turbo it for $4K.

redridge

Its not the cheapest, but it is the most noticeable mod you can do to your N/A Pcar. I think if you can install this yourself...wich is very realistic. It better than any bolt on mod... hp/$$$ wise...
I havent heard of a person who was dissapointed with this kit, power wise and dependability, very satisfied. I had a leak in the S/C from day one, it was sent back and had it resealed, and Im again... the people who were dissapointed were the one with installation issues... loose oil intake to the S/C, overfilled oil going to the intercooler... stupid stuff. This kit is well thought out and its all about the installation that will determine weather you will have a good/bad experience with this... but honestly, theres guys on here with 30k-40k miles with the S/C and still running strong... I believe Karlooz installed his S/C with 70k+ mile engine and is still running strong... 1999Porsche911 has well over 30K on his S/C,... and Im sure he beats on his car... and also properly maintence it.
I think the S/C is a great alternative to the TT with some benefits... i get more stares at my engine bay than a TT's at shows... and makes the car more fun. No regretts and would do it again.

10 GT3

Vortech doesn't make the kit, just the head unit. No head unit is CARB certifed. The complete kit has to be CARB certified on a test vehicle only. CARB certification is also only by individual vehicle applications. If the engines are different or if the factory emission equipment is different, you can't certify multiple vehicles under the same CARB number. They aren't going to mention EVO or other companies that do the same like Stillen for Nissans or Active Autowerkes for BMWs. The Evo kit comes with a V2 SQ.

The issue with CARB certification, unless you really screw up tuning and it is running extremely rich, is cost. It costs around $100K to go through CARB certification. How much of this are you willing to pay for? Keep in mind there are 49 other states to market to and all of which don't care about CARB. Sorry to be blunt, but it is true. You could always relocate to a better state.

They plainly list the boost at 6 psi. This is considered the safe limit on the 996's high 11.3:1 compression ratio and high octane pump gas. Ruf by comparison installs thicker head gaskets that reduce the compression 1.5 points to 9.8:1. With the lower compression thet run .8 bar or about 11.6 psi of boost.

Certainly. You just void the warranty. The ECU tuning is no longer correct and if it blows up, it is your fault. I have done this previously with with a Stillen kit for a Nissan. I started with 6 psi on 10.0:1 compression. After swapping to a 3 size small pulley, I was running 9.5 psi. Stillen used an old style Vortech linear rate FMU to ramp up fuel pressure and an additional in-line fuel pump. I swapped to a Cartech FMU to get proper fuel adjustment for the increased boost. In the case of a 996-997, it means taking your car to EVO or GIAC to have the ECU custom burned. Of course they will know you changed pulleys and will remind you that you no longer have a warranty.

There is no such thing as a serpentine belt that does not slip. The great the surface area (larger the pulleys in diameter and the wider the belt) the less the belt slippage. You just don't know how much it will slip. They are things you can do to alleviate some of the issue. If you were running 13 psi run off a serpetine belt, you may gain 1 psi by reducing belt slippage using Belt Dressings. Increasing boost, means a smaller diameter pulley and greater belt slippage. The only way to completely eliminate belt slippage is to go with a cogged belt, which is what every racing supercharger setup on the planet uses.