I have to post this because I woke up to a few messages from fellow members on here asking me if I really think its making this much power .

OK, is the car fast? yes its running pretty good for the parts it has. Does it make 750whp and have another 50hp in there? Well honestly I think for sure the car makes over 700whp, its probably in the 725-750 range depending on what dynojet you throw her on. The graph 08957 has shown has a smoothing of 6, so there is a lot of interpolation going on to smooth it out, the physical data will look more jagged and may achieve a lower number I haven't tried yet. Also I'm guessing some inputs, like temp, tire size etc. He has now provided those so we can update it with those. Sam and him are also still fine tuning the car, its close, may be done by the time I post this. I also have an engine model I have made and can use the datalogs to predict power at engine and at wheels we can compare to. Virtual dyno is backing out power by figuring out how long its taking to accel x weight to x speed. My engine model is predicting power based on engine airflow, desinty, bsfc, ve, etc. I have gotten the same #s from both simulations before on multiple cars (within 1-2HP compared to actual dyno), I haven't tried with 08957's car yet.

As far as exhaust and how much power is left in there. I know Sam is trying to strike the right balance of keeping the car happy with the current EP stage 1. If you really want more, you can move up to the stage 2, you have my predictions there on what the new restriction would be . I think its a good option giving you already have and like their product. Obviously a ton of choices here and I do NOT want to open that can of worms . How much more power? I think if you can pull a honest 740-760whp I would be happy. This is because even if we gain flow after the turbine wheel, we are still dealing with what is happen thru that turbine stage.

Another thing I wanted to add was based on the tons of logs I have seen from all sorts of setups and tuners...I think at this power level we can see 25-50HP swings within the population of cars with same or similar parts. Keep that in mind guys.

That's my advice for the morning

 

 

Guys here is where we have to be careful right? We can't apply this result as a blanket statement across all setups. For example, OK there was a small gain in top end flow, but what is the next bottle neck in the exhaust system? Ideally we would have the exhaust instrumented for pressure in multiple locations then we would know. There is quite a difference between EP stage 1 and stage 2. I expect there would be a difference between the earlier Gen 1 we'll call it Kline at 2.5" to what Sam is having them make now. I do not have restriction data on the newer Kline so I haven't made any predictions.

I have toyed with the idea of modeling my Kline but there is only 24 hour in a day But I can do it. I have modeled lots of stuff for Sam and made predictions...he can speak for the accuracy

Stop telling us how awesome your 991 is...I'm spending too much money already as is Speaking of spending money, we need to get you some upgraded vtgs for the 997 I bet it would be one of the quicker ones, that car runs good.

 

Agreed!


Just geterdone A418t81!

 

start with the DSC box. It will surprise you.

 

I think the results / dyno sheet speaks for itself

My approach in putting my car together was to focus on the best and most potent intercoolers AMS and turbo inlet hoses and great turbos - the By Design Turbos are KICK ***

Obviously great tuning is a huge part of the results here also

As Sam has said the best exhaust is a straight pipe off the turbo

Obviously every exhaust strikes a balance between sound / quality of construction and smell of what comes out the other end

At this point I am happy with the catted EP1 system but would look to sell the slightly used EP1 system at this point and upgrade to the louder EP2 system - obviously from my results the EP1 system is capable of making some serious power and would be all that anyone needs on the stock turbo IMHO

On the stock turbo the EP1 sounds about right to me although with the modified turbo and tuning the sound is much more quiet and thus the EP2 I think is better suited to bigger turbo cars

When I bought the EP1 a few weeks ago I never intended for any of this to happen but when I blew out my clutch as a result of the increased power I figured I may as well do the turbos at the same time

I do not want to get into exhaust war dramas - there are lots of great exhaust systems out there. The team member that Sam found to install my clutch for me (great guy) had a 996 with a catless Kline and I must say I really impressed with the docile sound at idle and the aggressive tone it had a full throttle - I can see why some folks are fans of those units


For me I want to avoid catless if at all possible because I just can not stand the smell of exhaust fumes and like my clean fresh smelling Porsche leather interior that still smells like new - I have had many catless performance cars in the past - after a while the fumes have an effect


Heck when I grew up all the cars had no cats and they all ran leaded high octane fuel - when you followed a car down the road with a cam you really smelled the unburnt fumes - seems like the stone age now but yes my first car was a 66 Corvair 180 HP turbo - flat six boxer air cooled - 4 speed - lovely car

 

Stef like I mentioned there is only so much time in a day. The physics based model I have built are for fun on my spare time and I have shared them with other members here who are interested. If I was in this business I can guarantee I would have characterized the entire exhaust not just one location. For example on your own product, you want to know pressure before and after the cat (gives you delta pressure of cats), in and out of the mufflers (gives you delta pressure of mufflers), in the crossover etc to know where and what all your losses are so you can properly optimize. In addition you would like to add in the dynamic pressure so you understand total pressure. I would handle the X pipe designs in a similar fashion. That aside, you were nice enough to post some restriction numbers you have collected. Using the data you have posted for your EP stage 1 and stage 2 I made physics based models to predict exhaust restriction at any horsepower, not just stock. As you know and you stated, the restriction you posted is at stock airflow.

I have thought, again for fun, to take pressure on my own car before winter hits. I'm contemplating going bigger turbos and knowing where the restriction is today is of value to me. I can predict my future exhaust flow thru the engine and then I could assess how my exhaust will performance without spending a penny on parts, just my time. We will see if I find time to do this before winter.

We can get much more complex to gain more accuracy like adding in swirl out of the turbine wheel, turbo speed, vane position, etc which is the correct way. But again I'm not in this business, this is for fun and entertainment though others may disagree of my definition of fun I'll let you guys know if I measure mine before winter

 

Winter is coming.....




lol...sorry Game of Thrones geek moment.


got, winter

 

ROFLMAO!!! Where is the meme!?!

 

Either way you slice it with 750 estimated whp I feel that i can benefit from a bigger exhust pipe at this power level - although the sound may be louder i feel that with these VGT turbos our number 1 enemy is back pressure which is probably at least 50 psi at the turbine inlet. Anything I can do to lower that number will improve the performance

 

Hmmm...wonder who predicted this?

BTW I have the engine modeled with Xona (GT30) Looks pretty good, not that its anything new. But now I have predictions for almost everything including turbine inlet pressure. I can tell ya how BBB's engine pumping work is looking like now

 

I appreciate the opportunity to help and enjoy doing the simulations. Good excuse to grow my datalog collection lol

Seriously I learn something new daily about this platform on the forum and or through contacts I have made on the forum. The constant gain in collective knowledge is what keeps me engaged and coming back. Once learning levels off then it becomes boring. Just happy to be part of it.

Enjoy the car 08957

 

I have been down this road many times on many cars

I am seriously having the feeling in my gut that the 60mm OD exhaust outlet pipes which are ideal for stock turbo cars making 400 - 500 whp is really starting to effect me at the 750 whp level

I am feeling that with a much greater boost level at 7,000 rpms - 23 psi vs 14 psi with the stock turbo and flowing about 30% more air through the pipe I am really limiting the top end power. The stock turbo is falling off on air flow as it approaches red line and with these TiAL By Design Turbos they just keep pumping out more and more air as the car is revving more and more - this is creating more and more back pressure than with the stock turbos - mostly before the turbos at the manifold but also after the turbo with another few psi. Any reduction in back pressure will aide performance


Just my two cents and personal opinion from tuning lots of other kinds of turbo cars with big power but I never used to like to see restrictions in the exhaust flow on cars making significantly more power than stock


I am going to have to upgrade this to a full 70mm system

Basically - I am running like two 375 whp Subaru STI engines and each one would be better off with a full 70mm exhaust than with a 2.3" OD 60 mm tip exhaust

Of course that same Subaru would be very happy with that 60mm system at 250 whp or 500 whp Porsche on the stock turbo with twin 60mm tips

Here is a informative article from back in the day

http://www.superstreetonline.com/how...ust-test-tech/

When I am done with exploring this theory I will have M3 run another comparison to see how this change in hardware has effected back pressure and power production and 60 to 100 mph acceleration

 

Who ever thought other wise....well I do not know what to say.

One of the 1st mods especially on a turbo car is to get rid of any restriction and make the exhaust exit the turbos as quickly as possible.

You can have a 5” before the 2.5” tip, but if it all has to exit out of that 2.5” tip, you were almost better off having a full 2.5” exhaust system.

JOHN at Speedtech has mentioned that if someone wants a quieter exhaust & they have a 3”, one of the just many ways his systems can accommodate is he they can just get his 2.5” exhaust tip to replace his 3”. He does mention that at low power it is alright and you “only” lose around 15whp in the mid range. That 15whp is only when the car is around 450whp, but John said the higher up you go that number goes up.

I made sure that I had a true 3”, catless (mufflerless as well, is his race version lol) with TRUE 3” or larger tips WITH NO necking down anywhere. Did the same with my Speedtech on my 996T and back in the Supra days ran 3.5” y off of my down pipe (which was a 4” elbow)with one side going into my stock exhaust and the other into a QTP electric cutout that shot straight to the ground right off of my down pipe.

Even if your at your turbo flow limit, your whole system effiency would increase.

 

If the stock tip pipes were actually a true 2.5" then the situation would be better but in reality the ID is closer to 2.27 " or 57.78mm

As I have suggested this being a dual tip system it works really well on stock turbo cars and the sound is perfect with zero drone in the cabin and a civilized driving experience which is really ideal in every respect with an amazing sound that can not be beat

When you convert to a clipped turbine wheel and a highly tuned ecu the sound becomes much more muted and stock like and in addition as you begin to push to higher air flow which is exceeding the stock turbo air flow at 7,000 rpms by some 30% more this means that the small pipes are filled with a lot of hot air

As a general rule of thumb in setting up turbo cars I like to see every connection and pipe on the hot side larger than the smallest pipe on the cold side

This is obvious because when the air is drawn in it is colder and only air - when it leaves the engine it includes combustion gasses and is much hotter and has expanded greatly

The 70mm systems are not true 3" set ups either but should be a significant enhancement over the 60mm at the power levels I have achieved

My problem is that I am a power junkie and one taste of this Europipe power and sound has set me down a path of much more intensive modifications than I was originally planning

Without any doubt in my many years of car modification and design the Europipe is the best made, best designed and best executed exhaust system of any kind I have ever seen - bar none. It is an honor to have such a piece of art created by true craftsmen on my vehicle. In a world filled with imperfection, compromises and defects Europipe is at the pinnacle of exhaust design and quality in my opinion. In addition, the customer service, after sale attention and support is second to none.

At the time of my original purchase I did not want a 70mm system on the stock turbos as I did not want to experience cabin drone and unwanted sounds for nominal gains of only a few hp over a more quiet 60mm system

Sadly my plans have changed and now I have outgrown the original exhaust system I selected

I had originally planned to take the car to the track this coming week but now my experimentation will have to wait another couple of weeks until I can arrange to secure and install the new larger exhaust system

My hope in doing this is to obtain "X" amount of power with less timing and boost than would otherwise be needed and with less back pressure and better cylinder evacuation between combustion cycles which is crucial to volumetric efficiency and stability of the tune

I remain firmly committed to running high flow cats and I believe that the technology on high quality cats has advanced to the point that the power loss and back pressure from a properly sized motorsports cat is not significant. I am not willing to deal with fumes, smells and odors from a fine car like a 997. I believe with the technology in high performance cats now that you can have your cake and eat it too. Meanwhile doing your part to reduce harmful exhaust emissions from coming out of your tail pipe and making this globe more polluted than it already is. One of the coolest things I loved about buying a 997 turbo was the OEM's claim that when driving a turbo in city traffic the air going out your tail pipes is cleaner than the air going in your air filter. While many people do not care about doing their part to try to reduce emissions I think we all have an obligation to be good citizens - just my personal opinion

I think my power results thus far basically on preliminary tuning and a small exhaust pipe show the tremendous power that can be made through the Europipe highflow cats and how well they work in practice