I need Rennlisters advice on a mod I am planning to have it done. This mod I was told is a bolt-on no internal engine modification on 1997 C4S to TT 410 HP
the cost approximately $14K. Anyone had this done your input will be greatly appreciated.
Thank you in advance.

Carlos www.p-car.com/porsche/carlos

 

For what its worth,

I have not personaly had Todd (protomotive) modify my 993. However, I have had some very close friends do some extreme modifications at the hands of Todd & all one can say is wow!! Nobody knows PCars like he does and I have been thinking about doing the same thing ($ is my main factor) If I were to do it or any major mod I would ship my car to him!!

 

Like Kristoffer, FWIW ...

I haven't had the Stage 1 upgrade installed in my car, but dealt with Todd Knighton of Protomotive quite a bit in sorting out the 993 engine installation in my C2. Extremely impressed with his knowledge--like a master mechanic and senior engineer rolled into one package.

I do have Protomotive's performance software upgrade installed in my ECU. Runs strong and flawlessly.

I've considered the Stage 1 upgrade, but suppose I'm still smarting from the $$ associated with installing the 993 engine in my car (post spun rod bearing). Will be very interested to hear how it works out for you, if you decide to have it installed.

 

Something I forgot to add. Bruce Anderson discusses Protomotive's turbo systems in his "Porsche 911 Performance Handbook," on page 162.

A few excerpts:

"What is interesting about Protomotive's approach is that though it makes all of its own external components for the Turbo installation, it maintains the Bosch Motronic engine management system, albeit with modified fuel and ignition programs to make them suitable for the Turbo installation. This is the same approach that Alois Ruf has used for so long. The Protomotive cars may not be as conservatively rated as the Ruf cars, or as well tested via the autobahn, but they are very fast."

"All of the cars that I saw showed good workmanship, and the turbo installations were impressive."

Hope this helps.

 

Hmm... 410hp? No internal mods? Isn't the compression ratio a little high? Of course, that might minimize the lag... Does that include an intercooler? Does the 14K include installation?

 

Hi D.J.,

According to Protomotive's Website, Stage 1 is intercooled, twin turbos, maintains the stock compression ratio with low boost (0.45 bar). The $14,500 price includes installation.

 

How does the risks (on overall engine problems) of the aftermarket turbo compare to the aftermarket superchargers being offered. The supercharger upgrade seems to be quite a bit cheaper (costs about $10k installed I believe). Any thoughts? Mike W

 

I would think the risks are about the same, which is pretty high. Here is my rant...

I trained as a Mechanical Engineer and spent a good part of my career as an Automotive Engineer, so I think I understand the issues. In both cases, you are forcing more air and more fuel into an 11:1 compression motor. I would like one of the manufacturer's to explain why they don't get knock in these engines, other than the claim that they have not blown one up (yet). With the knock control in a 993, the system will reduce (but not necessarily eliminate) knock and it robs power to do so. I would like to see what the pistons & cylinders look like after 10k miles on one of these systems.

Why not do a NOs system. It does the same - more air, more fuel, more power and should cost much, much less. I think the trade off is very straight forward. If you keep the NA engine internals stock, the more HP you make, and the more time you make it, the greater the damage you do to the engine. Rant off...

I am not saying don't do it. I am saying if you do it, realize the risks and potential downstream costs.

 

So, Mark, are you saying there's no such thing as a ($14,000) free lunch?

 

Of course there is Free Lunch - I'll even buy it (lunch) for you, but you never know what a guy drving a 60's big block will choose.

 

Mark-
Thank you for your response, I am wondering myself regarding the reliabilty of the engine by adding 125HP. But then .425 on
boost seems not a lot compare to stock TT @
.8 bar I think. In regards to Todd expertise
he knows his stuff. I could only wish any Rennlisters that have done this mod can give us pros & cons.

Carlos

 

Carlos -- the TT comes from the factory with a lower compression ratio than the n/a 993 to compensate for the added pressure provided by the turbos. You can't really compare the two boost levels, in the abstract, without taking into account the differing compression ratios.

 

I'm a little surprised no one on this board has a Protomotive turbo system installed, considering how busy they've been when I've stopped by the shop or tried to schedule my car for work. Anyway, there is one guy on Pelican parts that has a Stage 1 system in his 3.2 '88.

Pelican Parts Thread

I appreciate what Mark D. has said with respect to these mods and reliability. It would seem unrealistic to expect the same longevity/maintenance costs when pushing the envelope in this way.

That said, I suppose the question to answer is how much of an effect such a mod has on reliability and maint.$$? Perhaps the trade-off is acceptable considering the added performance? I believe Mark D. is suggesting something close to the same in the last paragraph of his post.

To be honest, potential reliability/longevity issues are another reason I haven't installed the Stage 1 system on my car--in particular, considering that I'm still smarting from a recent (1999) catastrophic engine failure .

 

Even if the engine internals are up to the task, what about the rest of the drivetrain?

Both the clutch and transmission on factory turbos are beefier than the standard units. I'd be equally concerned about drivetrain reliability on a aftermarket turbo modification.

MC

 

Exactly. If I knew there was a 25% chance of needing pistons after 20,000 miles, I might find that acceptable and go for it. At 50% in 10,000 miles, I would not take the chance. It would be great if we had this data, but I can't imagine a tuner having this kind of info. I am certainly not saying these conversions are automatically a bad idea, only that one needs to consider downstream repair costs as part of the admission price.