ZCAT3

I just traded in my 87 Carerra for a 95 C4 Cabrio. The 87 seemed to have a bit more raw power, despite the HP difference (problem was that I had a hard time driving the 87. My feet, size 13, were always getting stuck in the pedals, so my wife was the only one who ever drove the car). I digress - I had CT Automotive in CA install some bolt on performance upgrades - a Weltmeister power chip, a K&N intake system, and a Fabspeed exhaust). The stated HP gains for each are as follows:

Chip: supposed to produce 296 peak HP at 6500 RPM (see: http://www.automotion.com/am/page_li...=21500&p=30520 );

Intake system: 12 HP (see http://www.automotion.com/am/page_li...=21500&p=31077 );

FABSPEED 993 MaxFlo-System: 14 HP (see http://www.fabspeed.com/993.html ). By the way, these exhausts look really nice.

The total cost for these modifications (parts and labor) was less than 2k. If you add the HP claims together, it would be a peak HP of 322 at 6500 RPM. CT Automotive thought that I may get a "true 300-310 HP" out of this set-up. I have not had it dyno tested, but there is a marked improvement in power. On some test runs on local backroads my wife (a better 911 driver than me) was able to clock 0-60 in less than 6 seconds with the 2 of us in the car and without spinning the tires or really aggressively working the engine. I do not know what the stated 0-60 time for a 993 C4 Cabrio is, but the car is definitely faster with a wider power range.

I am wondering if there are any other simple "bolt-on" modifications that can be made to get a little more power. I prefer modifications that can be easily undone should I want to revert to the car's pure form. I am looking at the TPC Supercharger, but do not want to modify the tail. I would also like to hear other peoples experience with these or similar products.

JC in NY

Personnally I cannot evaluate horsepower gains of a few percentage points, whether it's real or placebo.

I think you will find that folks on this board people are generally very skeptical of bolt-on horsepower for 993 engines.

Ray Calvo

Obviously, you also believe in all those products they hawk on late nite TV infomercials!

I agree with JC; from what I have heard there is hardly anything you can do to a 993 that will result in a measureable power improvement. Exhaust is fairly free-flowing , and I am very skeptical of chip uprates from trying about 3 different chips in old '84 Carrera. I also find it amazing you feel your '87 was faster than the 993; I had the direct opposite opinion of my '84 vs. '95 993; then again '84 was a Turbo-Look Coupe and the 993 is a C2 Coupe. I bet your improvement is combo of psychological plus driving technique improvement with practice. Exhaust note I'm sure is louder than OE, which always makes car "feel" faster.

I don't like 0-60 tests on my personal car -very hard on the clutch. I always use a 3rd gear 3000-6000 RPM acceleration along exact same stretch of highway to do tests. If you like to brutalize cars, continue to do 0-60 tests, but don't b**ch at Porsche when you need a clutch, CV joints, or tranny rebuild at 20K miles.

I would say forget the power and learn to drive the sucker the way it was meant to be driven on a winding rural road.

Terry Adams

If Porsche could have added factory mods worth 30 HP for $2K retail, they would have done it. Varioram in '96 added 12 HP, and that was it for the 993. I don't miss the 'raw power' of the '87 911 Cab I sold

MarkC

Chaps,
The mods described are sensible and and cost effective for the 993.
The OEM exhaust is not bad but easily bettered by several aftermarket (Fabspeed US), Cartronic (Germany), and AMD (UK) included) manufacturers. They will all give you a little more hp on their own. But used in conjuction with a BMC air filter and a custom engine remap ie on a dyno for that specific car, you should get around 20-25hp.
To get more power than this will cost serious money and you'll be looking at forced induction or a capacity increase along with head and cam work.
Porsche sort of addmitted they could do it by offering the Perfomance/Sound enhancement pack, but a manufacturer will always be conservative with their fuel/ignition map to allow for things out of their control like poor fuel, unobserved service schedules etc.
Concensus here in the UK is that the post '96 Varioram cars are not worth their claimed 12hp over non Varioram cars. More resonsive in the mid range but very little more power. Comments?

John W

Mark,

what chip, filter & exhaust do you run ??

I know of AmD, but have not visited them as yet.
I know they do chips, but was not aware they did pipes as well. Is it a Millford system they sell, or what ??

Just interested thats all, as I too am in the UK (spoken to you previously I think)

ZCAT3

I appreciate all of your input so far. Although the subtle (or not so subtle) bashing I could do without. I do believe the manufacturers' power increase claims in most cases. You can ask any Porsche tech and they will likely agree that these modifications do increase power. As an example take a look at the performance enhancement articles at http://www.rennsportsystems.com/~porsche/2.html I also did some basic tests and made various notes before having the upgrades made to have comparison data. The power has increased without question. There is some psychological difference due to the change in engine sound, that is true. But the 993 is so tame, in both sound and feel, compared to an 87 Carerra, that I don't notice it much. My 993 is still much quieter than the 87 was.

For the person who noted that if Porsche could spend an extra 2K to get more power they would, I offer this - they also could have spent a few hundred dollars to put nice stainless steel exhaust tips on the 95 993, but they did not. I was shocked at how crappy the 95 exhaust tips looked on my car (pretty yellowed), so they have been replaced. Obviously, there is always more that can be done - the bottom line dictates they stop at some point.

As to my comparison with an 87, keep in mind that I hap an 87 coupe and now have a 95 C4 Cabrio. Both the four-wheel drive and the extra weight of the cabrio top reduce overall acceleration. I would guess my car is now on par with a stock 993 coupe.

MarkC

John W,

My car has the AMD exhaust boxes, K&N filter (with Soundenhacement airbox) and was remapped on the rolling road at AMD to suit the new induction and exhausts.

Jeff (Everett) of AMD doesn't say who makes the exhaust boxes, but they're to his design and look fantastic before you hide them under the car and cover them in mud!
They are very subtle below 4000rpm but sound superb above this figure. They also have a wicked little "chuckle" at any revs when you lift off.

Power on my '95 non Varioram went from 267hp before to 289hp after, measured on the rolling road. Subjectively it feels more responsive.

I drove a Honda NSX back to back with my car on Saturday and was shocked at the difference in throttle response. I thought the 993 was good, but the Honda is electric! And with just 3 litres (it was a '95 car) and 215lbs/ft of torque. Those things rev to 8000rpm and sound fantastic too. I think I want one!!

ZCAT3 - These mods work. There are plenty of reputable Porsche performance shops who can improve the performance of your car without compromising its reliability or longevity. Sounds like you found one of them.

John W

Mark,

thanks for the response.
I know AmD as they do performance VW parts as well (other car is a VR6 Corrado).

If you don't mind me asking, what sort of money was the exhaust ?? (mail me off-list if you don't want to broadcast it)

I'm sorely tempted, so its handy to know what sort of likely money I need to put aside.

By the way, mine too is a non-varioram (94 C2).

993Widebody

Sorry to tell you but you probably don't have the kind of performance gains you think you do. I have a 96 993 and did the following: had the car dyno'd by an experienced tuner, with much experience operating a mustang dyno. We took the baseline numbers, added a Fabspeed exhaust (which looks and sounds great), and the powerflow intake, then did another dyno. I got about a 5hp gain at the rear wheels. We then installed the PROGRAM (piggyback ECU remap) and got another 12hp at the rear wheels. I notice a slight difference in performance.

The tuner told me the numbers I was seeing were completely normal for the modifications I made, and to get any more HP I would probably have to spend much more, like 5-8k.

Hope this is not too disappointing , just stating the facts. Oh, and many others have done the same three upgrades and have come up with similar results, about 20hp more at the rear wheels. Possibly equating to 25hp at the crank

John W

Rob,

Maybe I missed something here, but thats pretty much what Mark said he got 289 - 267 = 22bhp increase...
Or were you querying ZCATs increase claims ?

I guess the real thing here is that performance increase claims for each part do no get totalled when you add more than one.
Thats is, an exhaust _may_ give 12hp, and a filter _may_ give 5hp, but together they almost certainly wont give 17hp.

SSilver

Here's my setup on a 95 993 C4 done primarily by The Racers Group. After seeing the printouts of the chassis dyno results from Tony, this is what we got. With the Fabspeed Cup exhaust, with the inserts in there was an increase of 7hp to the rear wheels, with the inserts out, another 7hp for a total of 14hp. This was after the 28 RW h/p from The Program. I had a drilled out stock air box with KN filter, put ont a PowerFlow intake and lost 5hp, so back to the drilled out stock box.

We re dyno'd the car a number of times to check these numbers. Across a number of syno tests, the numbers were corroborated.

SSilver

A little more info. My times with these modifications at Thunderhill dropped about 3-4 seconds a lap, at Laguna Seca about 2-3 seconds per lap.

DoubleNutz

Rob, that is alot more HP than I anticipated for even those mods!

I am putting the Dastek Piggyback (The Program) computer on my 96 Cab this week however I was unsure of what exhaust to use. Coming from the 928 world I am used to finding reliable rear wheel horsepower in 1-2 HP increments.

What will the piggyback ECU deliver with the stock exhaust? And what was the cost of your modified exhaust?

DoubleNutz

Sorry for being the dumb *** on this list but...What in tarnations is a "drilled out air box and how does it affect performance this way and, same question for ,,,"Inserts?"