I think you better do some more research there Enrique. Titanium is superior to stainless in high heat applications. One thing nobody has touched on is the different types of stainless and which one EP uses. I am guessing it is the normal 304SS. It wouldn't hurt to have the first bend be 321SS, which is better for high heat areas. Why is it better? It is stabilized with Titanium in it because of its better inherent high heat characteristics. All turbo headers should be made from 321SS or better, such as inconel.

 

Yup, but just using 321SS with double the pricing easily vs 304, and people already moan about pricing as is. If you use mandrel bend Ti , yikes. People are crying about the prices of a akro, they will be crying more with a true inconel, mandrel bend. That is F1 technology there. My welder is very young (23) can weld it, he say's it is easy to weld, just need super clean material, and very careful. Do you want to fork over $$ and I can make him weld it inconel. I looked into it, the prices were not pretty If done here. If done in Taiwan, which they have some of the best welders, yup about 1/3 of the price, but they will not use a mandrel bend inconel, unless you really fork out money for that too. I wanted to make only inconel exhaust, but trust me no one will want to pay the true price of what it cost to make. Maybe that .05% of the wealthy.

 

AWE has posted on this forum their backpressure numbers. It's not on their website, but they have openly given us numbers.

If every manufacturer used a stock vehicle, and measured backpressure at the same point, the numbers would be comparable. Provided that the programing and the vehicles are the same, a log of boost demand and a backpressure curve should be reproducible?

 

1. Please correct me if I am wrong, but AWE data suggests that it does change and it is not a small change (up to 2 psi I think) with the more free flowing exhaust.

2. Good point, but... someone did look at the 2 numbers simultaneously and did point out that as one goes up, so does the other one - I believe this was in EP's original measurement thread. (Also, there is a combustion event in between - also good point, but is that combustion event itself the same when boost is higher? A higher energy combustion will lead to a higher discharge pressure, no?)

When you have a chance, look at the back pressure measurement thread. The differences are much smaller than you might think (although no official measurement, it could be as low as the order of a fraction of psi - like zero point something psi). Useful when comparing to stock, but between after-market exhausts, so small that it's very much subjected to methodology error and its significance quite debatable.

 

Very interesting thread this has become, I think. More speculation :-) regarding the AWE boost mapping data vs. measurement of back pressure. IMHO, AWE boost mapping data is more useful and relevant, because it it is the more bottom of the bottom line.

Less exhaust resistance, etc.--->lower back press--->higher boost--->more dyno power--->faster car
(Simplified of course) To me, each improvement in any step in the head of the chain is meaningless if it does not lead to an improvement in the next step. AWE's data shows that yes, whatever resistance reduction, muffler change, tube design, etc., we did, did lead to this much better boost/hp. If you are to compare, this is the better bottom line.

Back pressure is an important number without doubt, but it is but one in the chain and is far from the end-all - especially because once you are down to the level of these <200 cpsi exhausts, the smaller differences have not been proven to lead to any meaningful differences, or any difference period, in EGT, boost, horsepower, etc. (anyone please correct me if I am wrong). I should point out that despite of much discussion, even the smaller differences in back pressure between AM exhausts(you are talking fraction of psi here) have not been proven by proper testing (third party, representative samples, etc.). IMHO, the importance of this likely small differences in back pressure among AM exhausts has been blown way out of proportion (not by EP), without any supporting proof.

 

This thread is really nice and educational...one easy way to determine whether an exhaust is better than other (in terms of power) is to measure EGT...I ve tested around 6 different brands of exhausts at the same run in order to find lower EGT...and guess what...EP2 was the winner...EGT is a result of many parameters...including backpressure...when you only replace an exhaust and repeat the run...you keep all other variables (almost) the same...That is the reason why any EP2 car here is better above 200km runs...Ecu wont pull timing of add fuel to lower EGT...

 

That is correct, the lower backpressure is the only reason for the hp/tq gains with our sport exhausts.

Be aware that this applies only to the Porsches up to the 997.1 Turbo. With the 997.2 Turbo there is no performance gain with (our) lower backpressure sport exhaust at the top rpm range as the ECU controls/limits the maximum boost pressure at the top rpm range. Same boost at the top rpm range = same hp at the top rpm range.

At low rpm and midrange the 997.2 Turbo ECU does not take over so the extra power is there and you'll feel it as well.

 

@stef: not possible for me to write you an email, get a failure report back every time I am trying.

And I am even not user enough to write pm's

 

Telephone...I know it's old technology, but it does work.

Phone 0032 38 77 47 32

 

Sorry to hear about your failure reports. I've received several e-mails during the weekend without issues.

Alternatively contribute to the forum, share some info on your car etc. You are very welcome over here.

 

F***k it's awesome )))
Ok now about exhaust. I can't decide Supersprint or Europipe

 

Well, it doesn't work out at the moment with private communication, so I will post it here. i hope the other members are fine with that, because it is maybe a bit off topic too.

---------------
I have a 2007 TT with TechArt update VTGs, bigger full alu intercoolers and some update manifolds.
At the moment I am rebuilding the car and update it to FL optic.

Engine wise i will go to some kind of bigger engine inlet ducts (Evoms, TechArt, Champion,...) Update boost valve (like evoms offers) New SachsRace 900NM clutch.
- any other recommendations to give my vtg setup the maximum outcome?

I could buy an Akrapovic setup for a very good price, but I am still not sure if it is the right setup or not.

For the moment i would like to keep the vtgs, but later, maybe next winter i would like to swap to a GTX 3071 setup.

One fact for sure is the FL rear bumper.
- i am not sure how far off the cut out from the FL bumper is compare to the 997.1
For sure it would be a mess to weld around at a 10.000$ Titanium exhaust, but luckily i could do it by myself if necessary.


Thanks a lot for your support!
Great place here
Regards from Germany
David

 

When I was in that decision making period, I had heard from a couple suppliers that it was the weld of titanium sheets that could fail early, not so much the titanium itself. And too, they didn't single out Akra exhaust, but titanium exhaust systems in general.

 

I've run 2 different Akrapovic exhausts on various cars. I love them.

But, they priced themselves out of this market, $8k - $9k is just silly. I love my EP1. Stef and Europipe build an absolutely fantastic exhaust.

 

On the 997.1 Turbo exhaust the outcoming pipes are 60mm and slightly tilted upwards. With the FL the pipes are 65mm and tilted downwards.

The hole in the 997.1 Turbo tip is off-centre and on the FL it is right in the middle.
The FL tips are much longer as well.

A good mechanic will be able to convert the 997.1 Turbo Akro exhaust so that it fits the 65mm FL tips.
Be aware that 65mm tubes are not randomly available.