Custom tuning w/ By Design - lots of power - need new clutch
 

My saga continues after being so long in the "keeping it stock club" I decided to turn up the wick on my 997.1 a bit and get away from the stock vacuum cleaner like sound

After installing the wonderful Europipe and AMS Intercoolers I found that the car adapted and lowered the boost levels slightly

Being stuck in this situation I turned to Sam at By Design who has provided world class customer service and technical guidance to bump up the Cobb base maps that simply were lacking

After a few data logs back and forth and a few of Sam's maps the car started to get significantly faster - even though the tune was having less knock than the original Cobb map and the data logs showing that things were very conservative and safe (I am very experienced around tuning and can read a data log)

The good news is that I must have picked up about 30 - 40 additional whp and the car felt much better. One thing I noticed about Sam's maps was that the maps he sent me took about twice as long to load into the car than the Cobb base maps which means that he is altering more of the factory map areas - this results in the car feeling more crisp on tip in and also avoiding knock that previously existed in that area. Also, it seems that he is working with the cam angle tuning also. It is hard for me to tell all of the areas of the map that he is working in as all I can see is the data logs and my but dyno feel driving the car.

The bad news - all this extra power and now I need a new clutch hilarious - we used to call that job security when I was in the car business LOL :)

Thanks again to Sam at By Design - best customer service and tuning experience ever

I highly recommend Sam and By Design

Thanks to Sam's tune blowing out my clutch with only 14k miles I ordered a stronger clutch and some other goodies from Sam and I am getting ready to turn up the wick

Now that I have someone reliable and intelligent and responsive to work with when it comes to my tuning needs I am finally ready to explore some additional modification

how much knock were you getting before, and after? and what are your ambient temps?

I was getting massive amounts of knocking with the OTS maps so I had to start running MS109 in my car to use them

I would do a data log if I were running any OTS non custom maps to check for knock

My ambient temps where like a blow drier when I had the stock intercoolers - reaching 137 to 140 at the and of a 2nd to 4rd pull in 75 degree temps

With the AMS intercoolers I am in the low 90's at the end of the same pull even in low 80's air temps as long as the car is moving

if the car is sitting still it does tend to pick up hot air soak from the engine bay which is quickly cooled off when you start to run the car

I would think the AMS intercoolers would be ideal for a road race style track day and not as good for drag racing unless you gave them a fine mist of cool water in the staging lanes - I think that would help a lot - I remember the Subaru STI used to have a top mount intercooler sprayer

Glad to hear about your experience with Sam and tune, sorry to hear about the clutch :D Sam has always treated me excellent which is rare to find as most of us know. All the dyno information over time you saw on my car in the other post are Sam's calibrations.

You had asked what software it was. Virtual Dyno is program. Like any simulation garbage in garbage out. It can be very accurate when used correctly. We have tested it multiple times, I introduced Sam to it and he has now used it multiple times with success comparing it back to a dyno. If you want to know more about it just PM me and I can give you tips on it.

Looking forward to hearing about the new goodies ordered from Sam.

Once the bug hits you and you start messing around then the end result is . . . well lets just say it is an illness

In any event I greatly appreciate all of your dyno sheets I greatly helped me in selecting my turbo choice and is very useful information indeed. You would think that the tuners and vendors would be the ones with this kind of great data. In any event your chart really showed the give and take between the various wheel options and hp vs. spool up and boost level - great info

I am looking to make about 600 whp on a conservative pump gas tune and see how I enjoy driving the car at that power level before making any other decisions

After having owned two very highly modified turbo AWD vehicles in the past for this project I want to maintain as much as possible the stock like driveability and feel as possible while increasing the power production

After years of experience I remember that when you have a 700 plus whp car on the road it becomes very hard to tell the difference between 50 whp one way or the other

There is a certain spot where the expense, reliability and breakage become overly costly and negate the benefits of increased gains for those who seek to maintain financial solvency

Like Iv'e always said you cant go wrong with Sam. Not only are his prices great but the knowledge he provides is priceless.

I agree he is a invaluable asset to the community and provides top notch support and guidance.

If anyone has any questions I would suggest that you contact him or Stef at Europipe and I have found them both to be really good people and a pleasure to do business with

Welcome to "Sam's Club", the other one, lol. You'll love the upgrades, it's such a transformation going from close to stock to well tuned vtgs. And if you still have the upgrade bug at that point I'm sure Sam will point you in the right direction...cough cough Xona cough cough

I have been reading your thread with great interest

With the amazing turbos that you have I don't know why you don't change the rods and oil pump so you can rev the car higher and turn up the boost higher and really take advantage of those turbos

Turbos like that really start to make serious power with higher boost which of course you can not run with these stock rods

3 words - money, headaches, expertise.

I hear what you are saying. I've gotten a taste of the power and I see why people want more. But I drive this car regularly to work so OEM level driveability is important.

don't know anyone around here who I would want swapping rods and don't want to be without the car for months again. If the opportunity came up, for example a camshaft issue that needed an engine drop and camshafts replaced, then maybe.

the xonas are still a worthwhile upgrade over my 68s even on pumpgas with less boost than I ran on the 68s

Bogg how much boost on your 68s? Did you ever check with a gauge?

Do you drive the car in the winter?

Why not change the rods yourself over the winter - you need a few special tools but it looks like a fairly straightforward job

I am planning to put in some rods over the winter this year - I never drive my 911's from December through March anyway. I think the number one thing this car needs to make it really enjoyable and fast is another few hundred rpms before you have to shift

From my years of experience in tuning cars I have found that turbos like the ones you have just got will always find the weak link in your motor / power train

Luckily from what I have gathered thus far when the rods go in these cars they do not snap in half like some other cars it seems like they tend to bend first

Back in the day I had a friend in South America with a really fast Subaru making over 850 whp. Since his Carrillo rods were literally bending, eventually they came out with the "Pro H" rod rated at 275 hp per rod which was a heavier rod that could take the power. The good thing was the Carrillo rods were so tough that the old style never snapped - they always bent slightly - kind of like a fuse for the engine limiting your power. With the advent of everyone running alcohol and the newer turbos rods are under a lot of stress

Lol, thanks for the good laugh. I limit myself to changing the oil and very basic external maintenance. You are obviously in a different skill league if you would consider doing this yourself. I've never encountered anyone that said this was a straightforward job...

How much boost? All of it hilarious


https://cimg6.ibsrv.net/gimg/www.6sp...c263d8d1a8.jpg

I didn't know it at the time but the 22.5 value just means the sensor is maxed, I don't know the actual boost that was delivered :o

When I was born I didn't know how to do anything

With patience and determination you can learn how to do anything

The best thing since I was little and I got my start working on my first turbo flat 6 - a Corvair 180hp 1966 I think everything has gotten easier with the internet. Back in those days everything was by shop manual.

With the internet you can find help on just about any topic.

One thing for sure - if you found a way to get some rods and maybe some head studs in your car that thing would be a real monster kind of like we used to say "taking off the panties" when the world was less politically correct

Having owned a couple of 9 second cars and gone over 1,000 whp I can't say I blame you for your apprehension but it seems clear to me that the rods are your next step

Myself on the other hand I am purposely keeping my build at 600 - 650 whp on the mark at this point to avoid many of the pitfalls I have been through in the past - in fact this was one of the main reasons why I bought a 997.1 in the first place (because it is so easily modified) and I like a manual trans car

Yes you would need a bigger MAP sensor - not sure if the Cobb supports that modification on this platform

You probably did not use ALL the boost as Champion claims the 68 turbos are rated at 475 per turbo which certainly would have finished your rods

I am sure that Sam had everything under control

You remind me of Prodigy :D

lol that's right, he came up with that

Cobb does support 2 bar map sensor.
I had a different brand Cobb custom tune and was in talks with Sam about a new custom tune when a coolant hose blew. Since the engine was coming down I decided to put on Xonas after a little research.

I would say you got away lucky with that "different brand" tune as without knowing what the boost is at whom ever was doing the tuning was playing blind. That "different brand" could have wound up costing you a lot of money

I think as a tuner the first thing you do when you see the map sensor voltage hit peak is stop and go for a bigger map sensor - OR - turn down the boost so the map sensor is less than peak. In fact on most tunes I would do I would set a fuel cut or boost limit right at the limit of the map sensor to prevent over boosting in the event of a hose coming of a wastegate

Now when that engine was down would have been a great time to do the rods - lol

Thankfully you are in good and safe hands now - I like Sam's careful and slow approach to the tuning process and starting off on the low side and working up slowly

Hey Sam, things look good, almost at goal. I think you misunderstood, the graph above is the Champion 68s maxing the stock MAP sensor.

That version of the tune was done on the Mustang AWD dyno so I'm sure he knew exactly what the boost was at the time. I just don't know what the number is for boost because it maxes the stock map sensor. Based on calculated "load" and the pbox performance I doubt it's much higher than 23psi or so, but that's just a guess. Not that it matters anymore anyway, lol. Drove the car for a long time with that tune and don't think there were any tune-related problems. The leakdown was very consistent between cylinders when it was recently tested.

While there are plenty of maps with boost pressure as an axis, there's still the MAF sensors for load calculation.

I have the 3 bar on mine and the maps scaled for it, but ever since I upgraded to the Do88 big pack, I haven't needed it as my max flow numbers are still the same at 20-21 psi as they were at 23-24 PSI on the factory piping and 997.2 ICs.

I'm also impressed with the big pack - keeps the temps under control even on hot days (i.e. they don't skyrocket)

It seems that you are making a lot of power for stock turbos. If you don't mind me asking how did you calculate the power level? If you are making that much power I would think out loud that no matter how much higher you raised the boost the power would not go up any higher.

The reason why the boost is lower for the same airflow on larger intercoolers is because the air is cooler and more dense. I experienced the same situation when I installed the AMS intercoolers. Based upon my experience the intercoolers are a huge benefit.

E85 explains a lot. But I wanted to say a few things about the dyno jet dyno after years of experience working on them - STD correction means STD as in sexually transmitted disease - depending on air temps and altitude the power is raised - the best correction is none and smoothing 5 is another typical dyno jet method to make a dyno sheet look smoother

Main thing is that you are happy as no one drives a dyno sheet but I think too many people are fixated on dyno sheets in the performance world. No one drives a dyno so that is why I prefer to log and drive my car on the street - have not had my 997 on the dyno yet

How is your driveability / cold start with the E85 over time ?

Any disadvantages to using E85 on the 997?

Have you ran into any problems?

I note by the way the reason why I know about the STD trick is because all my dyno "records" where always made on STD mode with a dynojet. Just the same way there is a lot of manipulation on Vbox numbers (people taking out seats - spraying intercoolers with NOS before runs etc) there is a lot of manipulation in the tuning world on dyno sheets

I am glad that you tuned your car mostly on the road - I have little use for dynos other than comparing parts and setting up timing curves for MBT

Thanks for all the great info and for being a pioneer in running the E85 on these platforms

Certainly a great 60-130 time

Were you able to get the injectors in without dropping the motor out? I am looking and it seems very tight for my fat hands - the AMS intercoolers were hard enough for me

I would like to run the 60 - 130 mph tests here but they will result in jail time in this area and the need for multiple Court appearances - anything over 100 mph in this area and you have serious problems

My best bet is to go to the track and try to run the testing there - sadly without a cage they will give me only one pass before they throw me out


Living near NYC is not the best place for enjoying high speeds

BTW - what exhaust do you have on the car and do you run any cats? Thanks

I have a cat myself - I went with the Europipe as they seemed to have about the largest cats

I am curious if you had any thoughts about what effects the high flow cats had upon your power output at these levels?

I am not that familiar with this platform but it would seem that the turbine housing looks like the biggest restriction on the exhaust side

After having a few performance cars without cats I don't want to deal with the smell and the fumes anymore. The 100 sport cats in the Europipe delete all the smell, fumes and noxious emissions. I feel like this is a luxury GT and should not have an exhaust like a Honda - while I do want to make it very fast

08957 yes there is same power there however its a function of airflow and the resultant delta pressure you get as you know. I made estimates for another member here using Europipe with upgraded VTGs and I think I was spot on based on the difference in performance he sees on the track vs. a similar car but with catless Europipe.

Assuming the same geometry, we can model it fairly easy. Its harder to model lets say your Europipe vs. a Kline catless. Too much geometry change for 0D.


With the VTG we would see the same behavior A418t81 saw swapping his intercoolers. If you target the same power it would be at a lower pressure or more open vane position. This will drop the pumping work gaining you BSFC back. Or you can use all that fuel again and make more power lol.

I should probably add, if the catalytic is large enough which is what Europipe is after, they should support higher flow. Ultimately you will find some limit. There is a member here with a 996 turbo (Powerhound), nice 3" exhaust with large cats however I don't recall the brand of them which did a back to back showing just run to run variability (no cal changes ). During that test he was in the 600whp range I think. Obviously a 1khp car would show gains taking the cats off etc etc.

Looking back to 2015 Mitch from Cobb did the best method of testing exhaust / turbo efficiency - by installing a boost gauge on a copper coil - here is the thread

https://www.6speedonline.com/forums/...eets-more.html

In that thread he was developing the Cobb E85 Maps and made 601 whp 636 TQ on stock turbos on E85 with a GMC exhaust with cats

The back pressure measured with just 20 psi of intake manifold boost was nearly 50 psi of exhaust manifold boost pressure

Needless to say with an excess of 30 psi of pressure at the exhaust side of the turbine the evacuation of the combustion is not very efficient

Of course I think the test in that case was missing a comparison of pre and post turbo pressure drop which would be more of an indication of the efficiency of the exhaust relative to the turbo itself. The differential between the two pressures - pre and post turbo is what gets your turbo spooling.

According to Europipe the maximum backpressure on a stock 997.1 exhaust is .44 bar or about 6.4 psi

The Europipe Stage 1 system according to Europipe cuts that down to .18 bar or about 2.6 psi

I would assume that these figures from Europipe were achieved on a totally stock car making about 480 crank hp - I will check with Stef on how these figures were obtained

In any event going to a straight pipe out the back from a Europipe Stage 1 would gain you about 2.6 psi off the 50 psi measured at the turbo which is not that significant which is why we notice that just adding a complete exhaust system over a stock one does not yield that much of a power improvement - Europipe claims 18 whp gain for its exhaust which goes from 6.4 psi to 2.6 psi - so I would theorize that taking off the exhaust completely on a stock car would be good for about another 10 whp or so vs. a good cat back system

It seems to me that the most significant restriction on our cars is the turbine wheel and the turbine housing which if you look at the chart provided my Mitch of Cobb shows what we feel when driving the car that the stock turbos begin to fall of dramatically around 6300 rpm as the back pressure in the exhaust manifold begins to rise

This being the case, raising the boost would only increase the back pressure in the manifold which is approaching very high levels and creating heat and ineffective discharge of spent combustion gasses between ignition events

What remains to be seen is what effect high flow 100 cell cats have upon the back pressure

The fact remains that the Porsche has the exhaust set up in a poorly configured location due to the engine location and has a lot of additional sharp bends that would otherwise be avoided in a conventional set up. The cats no doubt are very close to the turbos and a great source of heat

As I have said, I have previously owned many very fast street cars with no cats and open dump tubes and there is certainly a smell that becomes associated with having that kind of catless system

Thus car on my mod path I have liked the fact that the Europipe has not subtracted in anyway from the Porsche experience and only enhanced the car. The materials and construction being superior to the OEM unit and the cat working just as well as a stock one with no odor or smell what so ever even on MS109 fuel

What I am not sure about is whether or not I can achieve my desired power objectives while maintaining the cats and to what extent the back pressure and power loss will increase as I am increasing my power production with cats

At some point I may have to get rid of the cats totally

I guess the ideal solution would be to run a bypass valve system of some kind but most of the ones I have seen are bypassing the mufflers and not the cats in a Porsche there is not a lot of room between the turbo discharge and the cats

Back in the day many turbo import street racers would run a totally stock exhaust with a by pass valve to throw off the police and the competition - not to mention I would not be surprised if this kind of sound so close to the engine would not set off false knock on a 997

08957 I know the plot you are referring to, I even saved it since it was such good information (thanks Mitch). I'll expand some more on this subject since its my favorite and what I do for a living. For the following "we" means us turbocharger development engineers in the turbo OE industry.

In reference to the turbine wheel or housing being too restrictive this is not the case on the VTG. We oversize turbine A/R on VTGs, its rare that the turbine housing on a VTG is the flow limiting part of the stage. If you find one, someone screwed up :D. The turbine wheel is actually a high flowing turbine wheel. If you look at the design, its a very tall blade, high trim, little wrap telling you its meant for flow and not extracting work. Perfect for gasoline like this application. As you start looking through more datalogs keep an eye on vane position (reported out as turbo duty cycle because its actuator position). You will not find a datalog with a car at full load running at full open vane. This is tell you the turbine stage has more flow left in it. I fully understand most peoples experience is with a wgt or fixed geometry and where the comments of the turbine being restrictive comes from. With VTG its a little more complex. We can go deeper here but I'll leave it here for now.

Now lets cover the turbine inlet pressure Mitch reported because here is where its gonna get interesting for gearheads like ourselves. The reason you are seeing turbine inlet pressure skyrocket is because of high vane closure. High vane closure = "I need more turbine power to hit the desired compressor operating point". What goes into turbine power? The ingredients are turbine inlet temperature, turbine efficiency, and the easiest knob, turbine expansion ratio. Driving the vanes closed you are achieving higher expansion ratios, plotted on a turbine map it would like like you are picking on the fly a smaller and smaller A/R (for illustration purposes) as you increase engine speed. So why are we consuming so much turbine power? The compressor operating point is in the dumps. We are running the stock compressor in choke where efficiency is tanking consuming the turbine power. Back in high school this took care of itself on my friends Eagle Talon I use to mess with hilarious. Yeah we would hit 22psi but by redline we were down to 15psi since its a fixed flow turbine and the compressor running in choke was dragging that turbine down. There was no VTG to add the required turbine power to keep it at 22 psi.

On upgraded VTGs we run at a much better vane position and our turbine inlet pressure will not be that bad. I included a plot of my car with that same E85 file on stock turbos vs. when I switch to the larger 63.5mm compressor. You can see the huge change in vane position. And exactly as you stated, since now I'm at a better engine delta pressure, I'm effectively increasing my VE by being able to evacuate the cylinder more efficiently.

In the end its not turbine flow that everyone is blaming...its really turbine efficiency. Because of the turbine efficiency of this particular stage, we can only run the vanes so far open and keep a matched point to the compressor power desired.

Now to address the exhaust restriction deal. The affect on turbine inlet pressure is higher than you estimating. The reason is expansion ratio. If you turbine is running at a 3.5 expansion ratio, you would be multiplying your exhaust restriction times the expansion ratio and that's how it would affect your turbine inlet pressure. That's why we see huge gains when someone running 6 psi of backpressure goes to a free flowing exhaust. Moving from 6psi backpressure to 2psi gains you a 14psi drop in turbine inlet pressure. Its a significant number.

I used Europipe's published numbers to model the exhaust restriction curves as a function of exhaust flow (horsepower). I don't want to post these cause I don't want to start a pissing match hilarious I can tell you my prediction is accurate. Again if we use the same exhaust geometry its an easy calc. I can tell you the exhaust restriction you are at today if I know your airflow numbers and AFR.

very insightful observations.

what are your thoughts on the "clipping" of the turbine wheels that Tial Sport does on its VTG compressor upgrades? It would seem from what you are saying the compressor wheel is the limiting factor not the turbine

thanks

I'll be brutally honest even if may offend some of my colleagues lol.

Clipping in general when we do it in OE its NOT for flow. Its done to get a higher natural frequency out of the wheel. One of the many reasons for a speed limit on a turbo is the blade excitation. We can get into conditions where the excitation is so strong the deflection we see has strains high enough causing cracks and eventually a blade off event. Yes, the blade or section of the blade will come flying off. We can fairly easily predict when this will happen using some rules of thumb and a microphone to record the frequency of the blade when we "ring" it.

So what happens when you have to use what is already available and are not allowed time or funds to make a new wheel? You clip it! hilarious It will ring at a higher frequency ultimately letting you run a higher speed. So if you see wheels being clipped in the OE space...its for speed not flow (most of the time). This issue happens on both compressor and turbines...we can clip both compressor and turbines (typically higher clip angle).

The VTG again is a little more complex than a wgt or fixed geometry. On the wgt or fixed geometry the turbine tongue is what excites the wheel as the blades goes past it (pressure wake). In the VTG every vane is exciting the wheel. We have to do multiple things to make them survive in that environment. I'll stop here.

In the aftermarket you typically see clipping as a means to drop turbine inlet pressure because you gain flow (small gain, not life changing lol). You usually don't realize all the gain because you are paying an efficiency penalty at the same time. But now we go back to my earlier post...the housing and wheel usually is not the flow limiter on a vtg stage. Again I'll stop here.

OK so what do I think of clipping this specific stage. TiAL does it, my Protos are also clipped etc. I think its fine...aftermarket does it looking for the flow gain..ain't happening on this stage. However some of them may know, some may not, by clipping they bought speed margin allowing you to drive to higher pressures.

997 GT2 versions of this are clipped and have a bigger A/R etc etc...eh <shrugging shoulders>. The clipping is for the higher speeds allowing more boost and the A/R tweak is really just the resultant A/R from making a straighter turbine inlet (EVEN if the engineer who did was trying to get flow also, speed is main). The GT2 A/R is a small change. I know the maps are not public so I can not comment any further. For those of you who have GT2 turbine stages...yeah nice to have. For the cost($$$) I would spend my cash elsewhere is all I will say if you are looking.

There is a ton of detail on this subject and many of us have written papers on it. If any of you have access to SAE papers you can find plenty on this subject.