I'd like ANY feedback, good or bad, regarding chip upgrades, modifications, replacement, and related problems. Naturally aspirated 993's (96-98 OBDII) only please!

I've researched a variety of chips and "software upgrades". I've heard claims ranging from 12-30 horsepower increase over stock to reputable builders who say it's a waste of money.

My car has Fabspeed MaxFlo II mufflers, Carerra Cup (open) airbox and a BMC F1 air filter. I estimate it's pushing ~290HP in current trim. I typically run 93-95 octane through a blend of Unocal 100 and 91 "Super" California Unleaded" (yuck!)

Any thoughts on:

- Best chip upgrade (HP, $$, drivability)
- Best value ($$)
- Best customer service
- Reversability (easily returned to OEM specs)

Much thanks in advance!

MC

 

Hi MC,

I am not sure if this helps or not but here's some info from Steve's website at RennSport.


Rennsport Performance Software (Steve Weiner)

Cheers,
pin

 

Thanks pin.

Steve has been EXTREMELY helpful and patient with me. I'd like to hear some customer feedback before I make a decision.

Feedback can be sent to me by e-mail if anyone would prefer.

Thanks,

MC

 

Steve has my DME as we speak. He's the man if you're looking to squeeze out as much horsepower as possible out of the stock chip. He has different programs available depending upon what kind of gas you have access to, connecting rods, etc.

In my OBD-I '95 car I had an Autothority chip, and I was pretty pleased with it.

I should be happier with the additional 12HP stock in my '98 car.

I'll provide a report when I get it back.


-Matt

 

Hi MC,

I have a Protomotive performance upgraded ECU driving my '97 993 engine (transplanted in my '91 C2). I can say it runs strong and flawlessly. What I haven't done is dyno'ed the software upgrade. In fact, the performance software was installed the same time the drive-block was removed from the "brain," so I don't even have a before-after reference. I can say that Todd Knighton of Protomotive is one very sharp guy. Then again, so is Steve W.

Below is the link to Protomotive's web-site. They claim 20 hp for their software upgrade. Also, I don't think the listed prices are up-to-date. I paid much less to have my drive-block removed/performance software installed.

Protomotive

Suppose I haven't supplied you with much data of substance, but at least I've given you what I know of an alternative performance software upgrade.

 

I went through a number of performance upgrades on my car. I started with a '95 Carrera which was dynoed at 273 hp, which is pretty good. Many '95 993s have considerably less (some were dynoed around 260 hp). (Same holds for the Varioram 993's- not all have 285 hp. Friend of mine has a 993S which was dynoed at 274 hp.) I was told by a very experienced Porsche mechanic, that the really big hp chip gains only show up on cars that have less than expected hp. I added sport cats and a sport muffler combined with a reprogrammed chip, and it resulted in 287 dynoed hp. (from a well-known Swiss Porsche and Audi tuner) Not as much as I had expected, but then if my car had had less hp to begin with, say 260 hp, then it would have been quite a gain. (I later added varioram and the 3.8L Porsche kit and got up to about 308 hp. The more hp you want to squeeze out the more progressively expensive the whole exercise becomes) Since then I switched to manual valve lifters and expect about 6-8 hp gain, but will have to dyno it. I suggest you dyno your car first to see where you are.

 

993RS

Those are Crank HP numbers. Did you have the engine out each time you dynod the car, or are you correcting with the average 15%loss from a wheel driven dyno? If its the latter, the real wheel driven numbers are always better.

Just my $.02 worth.

E. J.

 

993RS - Thanks for the numbers. I second E.J.'s question. Was the dyno work performed on an engine dyno or a chasis dyno?

I am having my car dynoed on a state of the art "hydro" chassis dyno in the next week. It's still going to be rear wheel HP but, the dyno is mounted directly to the rear hubs so there is no data loss due to tire slip as there would be on a rolling dyno.

I'll post results when I get them.


I'm still looking for MORE feedback regarding chip swaps!


MC

 

E.J.
Why do you consider the numbers "crank" numbers? The measurements were done on the rear wheels and corrective parameters were entered to compensate for hp loss at the wheels. The measurements were carried out at Stadler Porsche Racing. I do not know the make of the dyno used. Please educate me as to what is wrong (so I get my 0.02 cents worth...)

 

993RS: converting from rear wheel horsepower to crankshaft horsepower uses an estimated (sometimes 'guessed' would be nearer the mark ) figure for the power loss in the drive train. The only way to get a true measure of crankshaft horsepower is to use an engine dyno - of course, its only the horsepower that reaches the wheels (or more precisely, the torque) that gets you anywhere, so an accurate rear wheel figure is arguably more useful in evaluating what has been achieved in increasing power delivered.

 

Thanks JohnM. All I was interested in was the comparative gain, and I assume this is correct even if a chassis dyno was used.

 

John is correct.

I guess if you used the same percentage figure for all measurments for all pulls then it is fine. I just wonder where the shop came up with the exact percentage of driveline loss?

Normally you will see a wheel dyno figure listed as something like: 227 hp at the wheels x 15% average driveline lost = 261 engine hp. As long as you use 15% for all calculations you are fine. I just find it easier to use the 'actual' hp number from the dyno.

Of course that is not much help at the bar or the track when you have to say your 993 made 235 hp on the dyno. I will say the last time I saw a car on a wheel dyno was at Viper Days at VIR and seeing and hearing the race vipers pull 550 hp AT THE WHEELS was quite a sight. Don't think they have a problem with the chicks saying their cars pulled 550 hp on the dyno. Crank or Wheels it really doesn't matter for them.

I am still curious what percentage the shop used as a multiplier and how they came to that number. Maybe you could politely ask to let us know.

E. J.

 

EJ,
We can get your car up to the 500hp level, we would just have to figure out where to put the second engine!
Those guys just vaporize on the back straight at VIR. I hope you, Chris, and John can make it to the ViperDays at Mid Ohio last weekend in April.
Greg

 

Looking at the dyno sheet they gave me: On the first measurement, they measured 242 hp a the wheels and came up with an estimated 273 hp. More interesting is the torque curve. Originally it was peaky (273), at the last "guesstimate" (308), the curve is pretty much flat. I will contact them next week to get more info on the parameters used and inform accordingly.

 

Greg - You bet they do!! But they also run out of brakes - I think you saw the video of the Viper you drove... wow.

I WILL be at Viper Days at Mid-Ohio, this time with the new car (maybe both of them!)

See you.

Chris