For those that have already done the Stage 4 GT update, is there a problem with either the transmission or connnecting rods. I see that almost all aftermarket tuners are updating the rods, transmissions and sometimes the head studs when exceeding 600hp. I'm wondering if anybody who has done an update but hasn't updated the rods/trans has had a failure or if this is being blown out of proportion...I see where the rods are supposed to be the weakest internal link then the head studs and maybe transmission also. I also know Porsche goes a long way in over engineering most components to last with extra power..

 

I have the Stage 4gt kit and do have the concern that its a veritable time bomb. However, I do know of TT's with more power and miles that have not had any problems to date(outside of the occasional blown hose) and have relied on tuners such as EVO and IA as well as the various boards for their recommendations. In fact, I have not heard of any engine failures due to power mods on any TT's to date outside of Chad V's recent issues. I don't think I'd go much beyond my present power level without upgrading the internals and rationalize that I'm fine for now given the low incidence of engine failures and the fact that I don't track regularly nor am I constantly on full throttle during normal driving. Still, I keep my fingers crossed and limit the occasions when I drop the hammer until I'm able to do all the proper internal upgrades.

 

Stage 4 GT and reliabilty don't go togther. From what I have been hearing Stage 5 is gonna be off the hook. I am patiently awaiting the annoucement.

 

I don't see how Stage 5 is going to be more reliable if it is making more power.

More power=more stress on all the mechanical components.

 

Evo now has the GT640, 700, 750 and 800kits. The GT 800 comes with new rods and related h/w. I would do the mods before I get to the GT800 level. If I decide to stay with the TT a while longer... It's a great ride, but theres a lot of nice stuff coming in the next couple of years! :-D

 

that's why you put in parts that can handle that stress. Isn't new internals part of stage 5?

 

I think with Stage 4gt, the main issues are fuel, meaning the stock injectors are maxed out, in addition the factory hoses are crap and with this much power and torque they get shreaded.

 

You would have to change a lot more than just rods and even internal engine components to handle 800hp reliably.

Just ask Chad.

 

I am running the GT 700 from Evo with the upgraded fuel system and my car runs great . lots of power and very smooth acceleration all the way to redline in every gear. no hesitation at all because i am getting addecuate fuel from the larger injectors. My next step if i want more horsepower will have to be internals , to be on the safe side.

 

Thanks for all the replies guys sounds like around 600hp is safe with the stock engine internals..

 

Tyson is correct. I will have some pics of what will go wrong on an internally stock 996tt motor later this week. The rods may be a weak, however to date I do not know of a single rod failure in a 996tt. Something in my valve train came apart.

There is a big difference in developing big rwhp and delivering it to the ground. Lot's of things will break. As for delivering 800hp reliably to the ground for any period of time.

 

johnnie,

You should be safe with 600 flywheel hp not 600 or more rwhp. The clutches I have seen for sale by most of the tuners would not hold up very long with 600 rwhp. That is if you really put the power to use. To get a clutch that could would start at about $6,000. depending of the disc material used. Furthermore, you need to substancially increase tire width if you hope to really use any of that power in first and second gears. And these areas are only a start.

 

Based on dyno numbers what is the highest rwhp figure that would be safe..I'm sure Porsche has built the engines to handle 600 flywheel, is 500-525 rwhp safe, is this around 625 flywheel
hp?

 

I am coming up on 10K at 609RWHP. I will be in the motor shortly to change some things, but not because this level has proven to be an issue.

 

Gald to hear this, I see everywhere including the most recent issue of Excellence that Ruf, RSI, Digitec and many others always upgrade the rods, sometimes the transmission and always the clutch. These builders aren't building 750hp engines either, Ruf claims around 600hp but RSI is claiming 710hp..I believe there has been a few failures and in the interest of building a quality product with no issues they feel if someone is going to pay 250,000 for a Ruf vehicle they don't want any reliability issues with the vehicle. We know that many factory GT2's dyno close to 500hp/500 lb/tq so Porsche has factored in a wide safety margin in the engine, probably 25% at least to be safe. This means the internals at least are good for 625hp(500hpX1.25)..Only issues would be fuel requirements and clutch life. Anybody ever have an axle problems or transmission problems. So far I have not heard of many problems at all, has Porsche really designed the engine for 650+ internally?? Maybe!!