[firefish]

Now there are three (that I know of) more or less bolt-on supercharger kits for the 968 and each one of these have taken on a different route to achieve their respective goal.

Imo, for a street and perhaps an occasional DE event ride, there is only on of these kits that feels right and we all know of which one I speak.
However, since it is a true-to-the-sentence bolt-on it means that there's little room for modifications should one want more. In fact, the designer of the kit has been very clear on the point that this kit is at its limit.

One of these kits is already running an intercooler which is nice. However, there is talk about it being not so bolt on and that there are problems with belt slippage. It is also pricey and the kit price doesn't even include everything.

I really would like to go for one of the a/c retaining kits, you know which, but at the same time it would be nice to know that there's more to get IF one's up for messing with management, injectors, compression, intercooling et.c. Perhaps I'll never go down that route shopping for even more hp and torque but I don't like putting myself in a corner.

So which one would you choose?

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[Fox944]

There are at least 4 kits out there currently for our cars. I would choose a D1R

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[flash]

here's the problem:

we have 11:1 compression

we have at best 93 octane fuel readily available, if you are lucky enough to live in an area that has that - many places only have 91, and most places will be down to 91 in the next couple of years

physics and our engine's construction limit how much boost can be applied and have it not explode, regardless of intercooler, injector, water injection, etc

even if you go stand alone management so that you can peel the crap out of the timing, and all the other bells and whistles to cool it down and throw lots of fuel at it so it won't detonate or run out of fuel, you won't get much past about 350hp on a 3 liter motor, and it won't be streetable at that level - it'll cost you about an extra $5k to do all of that after tuning

now, if you were willing to go to 3.2, and drop the compression just a bit (say about 10.5:1 or so), you should be able to run about 10lbs boost on an intercooled engine with bigger injectors and get about 375 - that will probably set you back about $20k after tuning - this is my plan for my next car (track car)

good luck

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[rhudeboye]

If money were no object, Id go w/ a powerhause 968 Turbo S conversion.

As for SCs,- SF claims a desirable output but you loose the AC and the finish product is a step backward in the engine bay. Most probably don't care but that's a problem for me. The 68s 3.0 is one of the best <b>looking </b>engines Porsche has ever made. I'd like to keep it that way.

So I would and will go the D1 route.

Oh, I forgot to mention that Bob will throw in a splitter upon my purchase.

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[firefish]

So, strictly theoretically speaking, will the sc unit in the favourable kit flow enough for these numbers and will the tension of the belt be enough to handle 10 psi of boost?

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[biotechee]

Fire-

What are your personal goals?

From everything that I have seen and read (caveat here- no real world experience as I do not own either an SC'd or turbo'd car), the SC systems are all designed with a ceiling or certain limitations in mind. If your looking for more power/flexibility/sky's the limit type of thing, you'd probably be better served going the turbo route.

I believe are the SC kits are designed with very specific purposes/criteria in mind and not conducive to "tweaking." If you desire to "tweak" and get more, I think the SC kits are not the way to go.

Just my personal opinion. YMMV

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[banditsc]

IMA Motorsports should have a Turbo kit out for the 968 soon. Maybe contact them and see if what you want is more inline with what they will be putting out.

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[jfrahm]

I think someone needs to buy, install and put some miles the D1R kit before this thread really goes anywhere. It might be great but it really takes a neutral 3rd party to judge it fairly. I cannot really tell from the pics but if it has a smaller SC head that is easier to fit in there and a better belt wrap it might be a better product. The MAF is very close to the SC but if the boost is nonlinear with the Rotrex drive system (or if the Rotrex just moves less air at 1000 revs) that might not cause the problems that it does on the 928 Motorsports kit. The 928 Motorsports kit bypasses a ton of air at idle, good for midrange but bad for the idle. I sorted this out last weekend by moving the MAF down by the air filter, it was mainly an annoyance but now it's sorted.

As for adding more boost/HP, the 928 Motorsports kit would be hard to boost more than Stage II. The SC head is capable of supporting a lot more HP than it delivers in the 968 but one would have to overdrive the belt at the crank and underdrive the accessories. I am not particularly interested myself, it's nice to drive as-is and I do not want to make it a beast that drinks E85. I've built cars in the past that were modded to the point of not being fun to drive anymore, after the novelty wore off. Oh and I bought a literbike.

Personally I think the ideal kit for the 968 would be a twinscrew but the R&D would be tough.
-Joel.

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[flash]

i think a big question to answer is "what would you do with the extra power if you had it?"

even if you had 350hp, the difference between that and 300, or 300 and stock, on the freeway, would be negligible - you might see a 1 or 2 car length advantage in a 3 mile run

a good example of this is our M3 vs my fully modded NA 968

the M3 has 333hp and 269ft/lb of torque, with a Cx of .32

the 968 had maybe 280hp and 245ft/lb with a Cx of .34

weight does not factor in here

clearly the M3 should walk away from the 968 - however, on the freeway, from say 70 - 100, there was little to no difference, regardless of gear, and in fact, the 968 might have actually had an advantage in lower gears

it takes a LOT of power to make a noticeable difference on the freeway - however, you would see the difference and be able to exploit it, in canyons, on the track, or just generally blasting around, as you would have more power down lower

i would choose based on the conditions of 85% operation of the car - if it is purely a toy, i might choose something that had more compromise in civility or dependability - if it is a daily driver, i would opt for dependability first - if it is a race car, i would opt for max power

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[firefish]

My goals? Well, I haven't determined them yet. Let's just say that I want to make my 968 all it can be but not necessarily in one giant leap. Perhaps I'll never get there, ever, but the thing is I tend to lose interest in a car once it is "finished" so it needs to be an on going evolution. Or at least I have to have the possibility to make it better in some aspect.

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[flash]

lol - well, there are kits out there that can provide that ongoing need for tinkering

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[biotechee]

Not trying to take business away from any of the SC vendors, but it sounds to me like you would benefit from going the turbo route. Your wallet, on the other hand, might not fare so well....

Again, it sounds to me like most if not all the available SC kits are just that - kits. There's not much else on the table to go beyond what is in the kit. They weren't designed for that. If you really want to tinker and be able to keep "improving" the 968 so you don't get tired of it, go the turbo route or develop the twin screw like Joel states. Either of these two options could potentially keep you busy for years.

No matter what, I will be jealous as I can't do any of the options at the moment! [img]style_emoticons/<#EMO_DIR#>/dry.gif[/img]

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[rhudeboye]

There's more to tinkering then just boost. Suspension within itself can be an ongoing thing, adding a little more appreciation with ever upgrade and adjustment. There's also weight reduction, intr upgrades and even body kits (I dont like any of the kits).

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[Fox944]

firefish, if tinkering is your thing....there is so much more to a car then just the engine. Suspension, chassis, Interior, exterior, transmission, brakes, etc are all things that you can tinker with to make the car faster around a track. And they can keep you busy for years.

I have modified several aspects of my car, (i'm in the neighborhood of 25-30K in mods, i'm afraid to add up my reciepts)...and i can still make a laundry list of things i would like to get have done that havnt been done yet.

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[flash]

lol - yeah - i've been at this one now for 7 years, and i'm not done yet

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[Scott Collins]

The modifying is the fun part for sure, after driving with the new mods of course.

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[94SilverCab]

Just my $.02 (and probably worth far less).

If I were to build a monster car, at almost any budget number, I wouldn't start with a 968. I would start with some platform that had a huge production number and a variety of competing suppliers. think (at various budget levels) of Miata, S2000, Corvette, etc. not a car that had 12,000 made and probably 2,000 left in the US. Especially if I was doing a build for the street.

At this point, if that were my goal, I'd start with something newer, like an Infiniti G37S and work it up from there (just me).

Anyway, it's always stimulating to have these discussions.

Jay

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[Fox944]

if you want to build a front engine 4 cyl Porsche for cheap (relative), the 944 Turbo is always an option as well. lots of potential there.

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[Pauli]

I think there is always the temptation to "have your cake and eat it too" Personally, if I'm going to have a car that I would drive to the city for dinner, but also drive agressively on a remote twisting and turning coastal road - I would not want much more than what an SC would provide for our cars. You are already talking approximately a 23% gain in torque & HP w/ the D1. On the other hand, if I wanted to track a car, but still wanted to drive it to the city - It might be cheaper to own 2 at the end of the day.

I had mentioned in a previous thread that I had the opportunity to test drive a number of high-end cars - The only car that I have had any experience w/ that I thought brought both worlds together was the Mercedes AMG's - the SL63 AMG in particular. I thought this car crossed over - but you are talking about a 140K car - The other cars costing as much as 600K, were certainly not cars I would want to drive to work everyday - they had the "fun factor" but that's where it ended.

If I wanted a monster, the second 968 would probably have an LS1.

Just me 2 cents

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[Monstrous4Banger]

If I were to build a monster car, at almost any budget number, I wouldn't start with a 968. I would start with some platform that had a huge production number and a variety of competing suppliers. think (at various budget levels) of Miata, S2000, Corvette, etc. not a car that had 12,000 made and probably 2,000 left in the US. Especially if I was doing a build for the street.

Jay

Huge modification, and vendor scene around the 951. The 968 TS was basically a 951 in a different skin, with more capacity.


I say if you want big power, do what Stuttgart did, turbo it. See my avatar. SC kits are awesome for their simplicity, and low costs. 300's is plenty in our cars. A SC will get you there. At a bargain no less. You wanna go beyond that? Turbo! Sure a SC could be utilized to make more than that reliably. You then start losing the low cost, simple factor of the SC. Running higher boost means the need for stronger internals, etc.

I think the D1 kit looks very promising. I expect it to do what it was designed to do well. If the budget was tight, and 300ish is enough for you, a SC is a solid choice.

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