Some background:
I'm coming from the Supra world having had my baby totalled by a careless Sears driver and having settled a years long fight to get a halfway decent payout. In the end I was still raped and stayed away from cars for awhile but the bug is starting to bite again. Looking at the 911 I see an opportunity to correct some things I didn't like about the Supra while hopefully ensuring that my big dollar investment isn't simply shrugged off should the worst happen.

I tuned the Supra myself to over 700WHP on a standalone until running out of airflow with the stock head\cams and was about to step up to over 800WHP when the car was run over. I'm not necessarily looking for that level of power in a 911 but I'd like to be within striking range of the high 10s my old car could do on DOT tires and pump gas w\meth (about 600RWHP). The AWD and larger displacement of the Porsche look pretty good to me! Having to possibly turn to a "tuner" to have my car's computer flashed\wallet emptied is a huge concern... Having tuned my own car and quite a few others I learned a great deal about engines in general and tend to get into the weeds. I notice driveability issues bigtime and helped AEM debug their software long ago as a beta tester so I'm picky. Are "flashes" delivering OEM like driveability? Having had a few "tuned" Supra brought to me barely running and seen what was programmed into their standalones by "professionals" I admit to some bias in this area

Anyway, doing research on 911 I'm running into areas where I have technical questions

Limits & Tuning?
What size are the injectors on the Porsche and what's the stock pressure? I see talk of "upgrading" the fuel system by running higher pressures with a tune. I'm interested in learning at what level the stock injectors give up. I've not ever been a fan of running higher pressure as pump performance goes DOWN - sometimes dramatically! On the Supra I had to run two Walbro 255lph pumps, staged, in order to provide enough flow at stock pressures while not overwhelming the regulator at idle - I used a gauge to find this. What flow is the stock 911 pump and has anyone ever found flow measurements for it at various pressures? 5BAR plus another BAR+ of pressure at WOT seems like a great deal of stress on the pump - do they die often?

Other than fuel - at what power level is the stock MAF sensor maxxed out at? I've not seen upgrades for this anywhere nor much concern about it. I tuned MAP sensed ECU but know that the MAF can be an issue when tuning based on airflow. If the limits are high I won't sweat this

Is there any user accesible way to reflash\tune the existing ECU? What about datalogging? I'm a data ***** and I datalogged all sorts of things learning where the bottlenecks were on my old car! A/F, air temps, fuel pressure, boost, you name it I logged it and studied it. It was fun disproving some myths by logging things like boost pressure regarding spool and intercooler sizing. Tuning and logging to find more efficiencies to increase power was half the fun of owning the car and I miss it a great deal.

General ?s
It looks like buying an X50 car is the way to go if I've an eye towards more power or buying a car already modded, yes? What exactly does the X50 package include other than larger turbos? What size are they, I'm having a hard time finding that out. Am I likely be looking for larger turbos soon afterwards? I learned to hate big lag and on pump gas found more area under the curve with smaller turbos but I don't want to completely sacrifice top end power for instant spool. Are the intercoolers or exhaust different on the X50s? Fuel system? The injectors especially are of interest. What sorts of power or flow increases are aftermarket intercoolers getting? Anyone measured pressure drops or temp changes? The Supra guys actually found that some of the eBay knockoff stuff performed well although I doubt anything exists for 911 on the cheap. I happen to be a fan of mass when it comes to intercoolers and also look for low pressure drop. I know a good fabricator and this is an area where I might consider rolling my own if moving from stock is really necessary. Prices could push me since the OEM units look somewhat simple in the pics I've seen. I really want to avoid fabrication though... Meth injection worked VERY well for me and the parts are dirt cheap but given a choice I'd like to stick with high test pump. I like the idea of greater displacement and ought to see more power at reasonable boost levels without it. E85 looks interesting if I could find a pump nearby!

I notice that everyone seems to quote flywheel power levels and not so much wheel power, why? I've not ever been comfortable trying to figure out\guess drivetrain losses and on the same platform everyone shares the same losses so this seems odd. 20-25% seems extreme even for an AWD car, is it really that bad? Why do vendors not seem to quote power increases from many\most parts and why does there seem to be so few back to back dyno tests done? Am I simply missing them? In the Supra world folks dyno tested just about everything to include exhaust shootouts with 5+ systems! I'm hoping to end up with a quieter system than the 4inch sewer pipe I ran before <ahem> At $1500+ I thought that system was rude but $5K+ for some 911 systems and no dyno sheets is amazing - I don't like paying alot for a muffler! I'd sure like to remain emissions friendly especially in an OBD-II car, do the 100cell catalysts allow this? Things like intakes often bring real world power from enhanced breathing but I've yet to see a test for even an air filter so far and that's pretty easy to swap on the dyno or even remove. Vac sample the intake tube at WOT maybe? Are many people doing this kind of testing? Seems odd considering the costs of some parts. <shrug> Am I just not looking in the right places for tests?

How's the traction control system on the 911? On the Supra it was deadly - as in liable to nearly stall you pulling into traffic if you hit a patch of gravel. Most owners disabled it ASAP including me after having it activate poorly ONCE. At the power level I ended up, able to spin tires at highway speeds rolling into the gas in 3rd, I invested in a Racelogic system which saved my *** more times than I can count. I'd imagine the more modern Porsche system would stomp the older crude Toyota system and not require the added cost - yes? Is the traction control in the ECU? Stability management? Just wondering what's lost if the stock ECU is dumped

I've seen reference to folks diving into the internals on these motors somewhat "early" it seems. At what power level is this "required" and where's the weak link - rods, bolts, pistons, other? I'm pretty sure the crank is rock solid! How about the trans? Six speed in the Supra was amazing and good to as much as 1KWHP and I'd like to not have to worry about this area. I see reference to some issues WRT to cable adjustment and popping out of gears - is this normally a big concern? I know from the past that cable linkages can be a PITA, do the cables in this car need adjustment normally? Clutches I understand especially with AWD, I previously solved this with triple disks and see them for the 911 too. I assume this eliminates the dual mass flywheel as it did on the Supra - much noise? Plates rattle at idle? Big job to install?

Okay, enough rambling - so many questions! I'll go back to lurking\reading for awhile now Appreciate any feedback\comments for the newb...

 

Looks like the X50 package uses K24-16s? Seen mention of different exhaust tips and mention of different intercoolers but nothing really concrete. Help? Is there a site somewhere that can answer some of these questions where I can research?

 

the ics are larger had a set and put them on my996tt thelated a short then replaced them with evos ics(larger more effective) so i would not buy an x50 for the ics alone..good luck and have a great time modding

 

Ya, this would be more for the turbos than intercoolers I think unless I found a standard car cheap enough to justify the difference. Just trying to understand what additional values the X50 represents for the high cost on the original sticker.

For datalogging I've come across Durametric, can this be used for logging or is this mostly for diagnostics sort of like the VAGcom on VW? At least the VAGcom can make some mods although not for performance. Is there something better I've yet to find?

Still interested in MAF and injector\pump capacities and limits etc...

 

First of all, welcome. Second of all, this forum will tell you almost EVERYTHING you've asked. You just have to use the button on the upper right hand side that says "Search". You have a lot of reading to do...enjoy, you will learn more about 996tt than you will likely want to know...

 

Come on man... we've discussed lots of this stuff elsewhere... You want to drive mine???

Come visit... get some schooling... This deal isn't an old school Datsun, and it ain't no Supra, what we've previously discussed is what it is...

Making 600WHP will cost you a little. Makkng 500 WHP won't. You can make decent power for cheap with these cars. If you're looking for a deal, look in the for sale section and ****** up Christians K24G18 car and start having fun... 600WHP is just around the corner. However, do you want big block torque or peak power? This is where you might want to visit with some of us locals and sort it out... Don't be fooled, A 996TT will support plenty of power on the stock fuel system with a 5Bar FPR. However, if you're going to dive towards the deep end of the pool, you'll need more than a fuel system upgrade for LONG TERM high HP numbers.

You want to be a short term hero? Or a long term player in the game?

This isn't a Supra, so get that stuff out of your head...

Mike Kelly

 

Mike, an engine is an engine and engine management is engine management no matter the manufacturer. I tuned Honda and Ford as easily as I tuned Supra because of this. Max out the MAF and you lose control of fueling. Overpressurize the fuel system and pump performance can tank or injectors can lockup. I've noted discussions elsewhere here where tuners are hitting 92% and above injector duty - no matter the vehicle I know what this means. At what voltage is the MAF at say 600WHP? That's a valid question no matter what's generally "accepted' or not. I suspect the MAF is fine judging from HP numbers posted but high injector duty is scary and I have seen, on multiple occasions, what high system pressures can do. I've tuned, I know what worries me.

600WHP would likely do me fine, especially if it's no muss no fuss. But I'd like to know where things stand at that point with regards to the edge. I didn't start out to build a monster Supra but in the end it was pretty out of control and it could happen again! Knowing limits and pitfalls is what I'm after. Yeah, I'm searching and looking but not finding answers at this level of detail hence my questions.

Yah, I might like to try a ride in your car but I've not driven anything high powered in a few years now so it'd be a slow roll <sigh> I'm still working up to popping this much cash into a car at one shot. I've lost one car from events not in my control, if it happens again I will want to be sure I'm well covered...

P.S. Could you please link Christians car?

 

https://www.6speedonline.com/forums/...-01-996tt.html

Basically a K16/24 car (Mine) or a K16/16g car will be good into the lower to mid 500WHP range, depending on fuel type (Race gas will obviously get you higher numbers) on a stock fuel system with an upgraded pressure regulator. Larger turbos (like K24/18Gs or even larger) will require injectors/ pump upgrades to take full advantage of the available power. But then you're going to run into issues with the motor. Every tuner I've spoken to has said that 700BHP should be the max for a stock 3.6 liter turbo motor.

By the way, you won't find much on running a standalone system. I don't think anyone here is running one on a 996TT. I know Tym Switzer was working on something, and he was considered a "pioneer" in standalone tuning. Point is, this car is going to be MUCH more complex in trying to integrate and standalone into...

Good luck on your search, and you know where to find me when you want a ride.

Mike

 

I think the issue you are going to have is that NO ONE makes a stand alone for this car...yet. There a few here that have done it, but it's NOT EASY. There are MANY tuners out there...You seem like you want to tune your own car, with a 996, probably NOT gonna happen.

 

Ah, this is helpful! So 700BHP is about max before things go boom? What goes boom? Is the transmission, transaxle, etc. all still good at that point? The very last thing I want to have to do is find myself swapping halfshafts or something - ick!

It's not so much that I wish to run a standalone, it's that I wish to know where parts run out of room so to speak. Injectors are a good example - from my reading here some tuners are pushing them pretty hard - I'd want to avoid this longterm. Part of my issue is having seen what some "tuners" for other marques put into their tunes - most of the time you get a "tune" that "worked" for the last 5 guys through the door with some minor tweaks. Total attention to detail is not always very high, sometimes this is okay, sometimes not. Having BTDT I tend to want to know details. For injectors if I knew injector size, rough BSFC, and rough drivetrain loss (20+%?!), then I'd know about where they run out of room with some math. MAF - on many cars this is both a restriction to airflow and an electrical issue. Many cars find themselves trying to make power while sucking through a restrictive soda straw and thus upgrades have been made. Some, like Mustangs, run out of electrical range AND airflow. The guys who are simply slapping range adjusted "42lb" MAF on stock ECUs don't understand what they are doing is BAD. I see some guys here swapping thorttle bodies and plenums but no one swapping MAF that I've seen, is it not a restriction? How big is it? Measuring to see if this is a problem is pretty easy BTW.

Anyway, I digress. I simply want to understand going in where limits are. Going standalone on almost ANY new car with OBD-II is a freakin' nightmare. Reflashing the OEM ECU makes a TON of sense. OEMs spend TONS of time getting driveability "right" and you get to start from their baseline. WOT is actually EASY - I could do it in 4-5 passes tops starting from a good basemap and if I had wanted to I could use Excel to build a WOT basemap from scratch for fueling (on a MAP sensed system). Timing is the tricky thing but this isn't the place for a cylinder pressure discussion. Driveability is where OEMs have it nailed and standalone tuners have to spend time - and seldom do. Flashing the OEM ECU is smart, given a choice it's what I'd want I think.

Mike and I have spoken before and it sounds like getting the software to reflash the OEM Porsche ECU isn't likely to be easy or cheap if even possible. As much as I like to do this I'd actually be willing to invest some decent coin but barring that being able to log what was going on when I desired would be a requirement for me. Knock sensor activity, airflow through the MAF or voltage, temps, RPM, A/F, throttle % etc. A/F is a biggie, on my Supra that was monitored by a realtime meter in front of my face and at WOT I had an ECU triggered warning light on the piller it was so important. If I cannot have control I want to at least have knowledge and preferably something that updates much faster than 10 times a second.

So, was I right that the X50 option has K24 turbos at least? As that sounds like the sweet spot if buying "new" else upgraded already by the previous owner.

 

blk-Its good to see you posting again!! I've always held you in high regard over on SF when you had your car and were posting alot of useful information. I'm sure you probably remember me from SF as well, so you know my background too. I've had my 996TT for almost a year now, and it was bone stock motor wise when I bought it. I now have custom K24 turbos on it with Borg Warner extended tip compressor wheels that flow very similar to 24/20g's. I have also added some 58lb injectors WITH a 5bar FPR. Also have a Greddy Profec-B BC, Maxspeed exhaust and headers, EPL divertors, and a custom EPL flash. I was in the same boat as you as far as tuning goes...I tune all of my own cars, and I was very hesitant on letting someone else tune my car. After numerous phone calls to tuners, I finally selected Tony at EPL, as he seemed "on the same page" as I was as far as tuning was concerned, and what my final goal with the car would be (650-700whp on high boost and race gas or pump/meth). He was the ONLY tuner that I spoke with that wanted to do meth. on a 996TT and we both knew what great advantages it brings to the table when setup and tuned properly. He also took the time to answer all of my MANY tuning questions, and by talking with him he tunes very similar to how I've learned to tune as well, so it was really a no brainer to select him.

There WILL be a new stand-alone coming out for this car in the next week or so when he posts up all the details of it running on his car (I've already ridden in this car with the stand-alone on it while at the TX meet this year). He is a BIG name in the tuner arena as well, but somewhat new to the 996 game. This system will not be for everyone though. I think this system will be best for those people with built motors and big turbos looking to extract every last bit of power out of them, or for those who like to tune their own cars. I don't want to steal his thunder too much on this, so I will let him post everything else about it. Look for his post soon in this section.
So far on my car, I have made 565whp on PUMP gas with the stock injectors and a 5bar FPR on about 1.2 bar. The day after the dyno I installed the new 58lb injectors and went out to do some pulls, but the clutch started slipping when I tried to do any pulls. With a new clutch (that should be installed soon)I hope to be close to the 650+ whp area at 1.5 bar or so on race gas. My MAF is currently MAXED at this power level (4.95 volts) but with Tonys great tuning, and I am still VERY safe at mid 11 a/f ratios. Tony is also working on some new MAF's that should be ready to go soon, and I'm sure I will put one those in my car when it is ready. I know how much you like logging your car, as I am the same way. You will be VERY disappointed though. THe Durametric that I have has a VERY slow sample rate, and the way that it is displayed leaves alot to be desired as well. Its nothing like logging an AEM!! I was very disappointed when I first started logging the car. Now that I'm a little more used to it, its a little better, but still a far cry from what I'm used to.
I can't remember what the stock injector size is, but with a 5bar FPR you are good to about 600whp, but at that point you are running very high duty cycles. Like I said, I made 565whp with stock injectors and a 5bar, but I'm sure my duty cycles were very high. Thats why I installed the bigger 58lb injectors. This setup should be safe to 650-700 whp now.
The stock front 02 sensors on these cars are actually widebands stock!! The stock ECU has a great knock control strategy along with instant feedback from the widebands to make fueling changes.

My car is actually still for sale. I have it posted in the F/S section, so if you have any interest in it, then let me know.
I hope I helped out a little, and if you want to talk more about it, PM me and I'll give you my number ( I think I used to have your # but lost it a long time ago).

Tim Iacoli

 

Nice to see a familiar face! I noticed our hardtop friend here as well Would you believe I still get tuning requests for Supra 3 years after I stopped posting?

The datalogging rate doesn't surprise me too much The OBD-II dataport rate is pretty pathetic. Hopefully there's some sort of knock counter or other way to see what's up. I'm almost positive that Porsche uses W/B O2s so A/F ought to be readily available anyway.

Anyway, good news on the standalone. I'm not sure I'd want to go full standalone if I lose some of the nice features like stability management or traction control but I'll keep an eye out. OBD-II emissions is also an issue in my area, paying off inspectors and other hinky things is an activity I'd be happy avoiding. Leveraging the OEM's driveability tuning would be nice. An upsized MAF ought to allow added range, is the OEM unit also an airflow restriction? If it's maxxing out I'm betting it is!

I'm not 100% surprised at the MAF voltage reading. That your tuner has managed to keep A/F under control is commendable, I'd love to know more about how he does it! Airflow is one of the core inputs for a MAF sensed ECU, I wonder if the Porsche ECU has a MAP sensor it fails over to?

Interesting that your tuner doesn't seem to have the same engine concerns that Mike's does. At what power level are you comfortble at on a stock bottom end? FWIW on the Supra I was looking for a way to run a dual fuel system and if E85 had been available I'd have been all over it - I've seen one car here runing it already and it's great stuff. Funny that what I used to pay for race gas is what pump was going for recently. Sadly E85 is still rare here but for turbo performance cars it's awesome!!

 

This isn't "Mike's Tuners opinion". It is the general consensus amoung tuners.

Mike

 

So 700 flywheel HP is the limit? With a drivetrain loss of say 20% that means 560WHP is the agreed upon limit?! That seems low. I know the Porsche cranks are pieces of art with multiple main supports. I would expect good pistons and decent rods too. What goes bad at that level? Aren't quite a few people pushing a good bit past 560WHP? Heck Mike aren't you pretty close to that?

I know my pump gas tune with meth was close to 600WHP on the Supra and it was enough to pull a high 10. With better traction and a similar weight the Porsche ought to be pretty close to that I'd think. I never ran mine on a full race gas tune but felt 10s were fast enough. Even if I'm limited to the 560WHP range that might be enough to keep me happy.

These motors aren't cheap, what's it take to go through them for rods and pistons? <shiver> Really amazing how strong the 2JZ proved to be in the end, wonder if maybe this motor has more strength than folks give it credit for too.

 

That is why it is taking so long for the "truth" to come out. Nobody wants to be that guy that finds out what the max number is. There is one member here that had a failure directly due to rod fatigue. There is a thread...with pics of pretzel rods, do a search. Not sure of another one, but it seems tuners are sneaking up on it, as there are quite a few cars here WELL over 600whp on stock bottom ends and so far so good. Only time will tell as we keep pushing the envelope...

That being said, these cars at the 550-575whp level are really a fun car and exhibit none of the crappy qualities you might expect from a high HP street car. One of the few 600whp daily drivers.