UT_farhan

What is the main difference between an exhaust that has 100 cell cats and one that has 200? Does this have a significant impact on HP/performance gains?

GTRNICK

Hi this is totally dependent on the power levels you want to achieve at the end.

For e.g. if you are not going to go above a stage 2 then 200cell is sufficient but if you intend to go stage 3 or above then you will start to see the benefits of 100cell (obviously for all out performance no cats is the way forward).

Another way of putting it you are probably talking around 5hp to 10hp loss on a stage 2 and then obviously the loss climbs as the power climbs as you are trapping heat in the exhaust area and I think from memory any figure above 850*c (could be 950*c) the ECU starts to reduce the timing of the engine.


Also I would like to say that on a stage 2 the 100cell will allow the temps to remain lower for much longer than the 200cell so hence not only do you gain power but you also get to keep your power for much longer periods of time as the heat is escaping much quicker.

Macster

All other things being equal the 100 cell converter should flow more exhaust gas, be less restrictive.

Whether this registers any improvement in hp/torque depends upon how good the rest of the exhaust system is, particularly the exhaust system before the converter.

It also depends upon whether creating less restriction at the exhaust positively or negatively affects the engine's breathing ahead of the converters. For instance, optimum valve timing is somewhat dependent upon on the characteristics of the engine's exhaust gas flow.

There is also the question of how well the exhaust gases will be processed by this 100 cell converter. Less surface area unless the converter is made longer so the surface area stays the same (but which can then work to restrict exhaust flow) means less catalytic metal in contact with the exhaust gases means less efficient/thorough processing of exhaust gases.

The DME will attempt to adjust fueling to try to get the numbers it wants from the O2 sensors after the converters. This can result in less than ideal fueling and this can impact hp/torque numbers.

The only way I know of to be sure of any improvement is to establish a baseline of what the engine currently does and this should include checking the air fuel mixture using a 4 or 5 gas exhaust analyzer.

Then swap the 200 cell converters with the 100 cell converters and retest.

jhbrennan

Here's some additional info about the differences between 200 cell and 100 cell from Europipe:

The foils of our ø 153mm sport cats are perforated with holes so the exhaust gas flow can enter into the neighbouring channels. Conventional cats have just an axial flow pattern while our cats will flow axial, diagonal and radial. The exhaust gasses spread evenly inside the cat which results in lower backpressure. These type of cats are also used on the current Porsche Super Cup cars.

The cross section of our ø 153mm sport cats is 40% larger than ø 130mm cats, 60% larger than ø 118mm cats and over 100 % larger than the commonly used ø 108mm cats.

These big size 100 cell cats will create less backpressure than higher density cats of the same size. (same diameter + length) Low backpressure on turbocharged engines is beneficial for both the horsepower / torque and the throttle response.

The volume of the sport cat, its total surface area, the amount / content of the precious metal coating and the addition of heat shields are the key factors in having a long lasting trouble-free cat converter.

A large catalyst surface area allows for better exhaust gas conversion efficiency, durability and cleaner air.

We don't offer 200 cell semi-sport cats on our sport exhausts because these are more restrictive than the real 100 cell sport cats.

Our big 100 cell sport cats do not cause emission issues or check engine light problems.

UT_farhan

Thanks everyone for the responses. So when I end up going with a tune (FVD or Softronic), I'm assuming they will need to know that the EP exhaust is 100 cell, and will they adjust the tune accordingly?

speed21

The "exhaust system" on a 997tt.1 actually begins at the cat. The only component ahead of that is the exhaust manifold and turbocharger unit.

Valve timing is not determined by the exhaust system itself. If you are referring to the scavenging effect, which is a back pressure related situation, this mainly applies to a naturally aspirated engine. Using the example of a too large diameter AM exhaust being fitted to an NA engine, the scavenging effect can be removed due to the loss of necessary back pressure required to create the scavenging effect environment. Accordingly this will actually remove power. The length of the pipes and diameter is also very critical.

A turbo charged engine generally speaking requires no back pressure as the turbocharger unit creates a natural restriction by way of the exhaust impeller which accordingly maintains the scavenging environment behind the valves. Again the exhaust pipe length is relatively critical (still) but the increase in diameter being the main enhancement of the reducing the back pressure component after the turbocharger. This is also where a 100 cel cat is superior over a 200 cel as there is automatically less restriction = less back pressure after the turbocharger iykwim.

This question has been answered (please read link) so at this point in time there is thankfully no longer the need for any further speculation on that point.

You will find, using EP's most recent smog testing, their 100 cel cat is certainly doing a superior job over anything else in this instance and clears up any preconceptions the 100 CEL is a backward step in reducing smog over the stock cats.

http://www.6speedonline.com/forums/9...ml#post3954335

In so far as my own personal experience using 2 well known and highly regarded AM systems on my own 997tt.1, one system using 200 cel cats and the other 100 cel cats there is absolutely no doubt the 100 cel system produced a far superior outcome in terms of both throttle response and a seat of pants acceleration improvement right across the entire rev range. These differences were unmistakeable.

I continue to hear stories on these forums of am systems requiring a tune to benefit the actual installation of the system, whereas on the other hand the 100 cel EP system requires no tune at all for the user to feel the immediate benefits and gains and a tune can only make it even better again if that is the users pursuit.

I personally found the 200 cel AM system to (unquestionably) rob power at certain points in the power curve over stock, so whatever reduction of back pressure the AM system was really providing over the stock system in essence could not be felt with the stock tune file. That said there was a slight improvement felt immediately on throttle application using the 200 cel system however beyond that point there was no improvement at all, in fact as I said earlier there was a penalty being felt over certain points of the power curve indicating a drop off in comparison to the stock system.

This test was done back to back installing both 100 cel and 200 cel systems on the same day, same temperatures, same fuel etc. Just as an FYI.

nota_troll

Sorry to resurrect this old thread but I've spoken with a couple reputable vendors and have been told the 200 cel cats are better because they will not cause a CEL.

93ls1rx7

Sometimes they do, sometimes they don't. Best thing to do is to have the rear O2s removed in your tune.

jhbrennan

The 100 cell cats used by Europipe never cause a CEL.

nota_troll

Yeah. I've been told EP is sweet spot for an exhaust. Just curious...hey at least I researched first!

Ibanezgod

Any input on Kline exhaust and using 200 vs. 100 cell? Don't 200 cell cats have more longevity?

clb00196

I ended up buying this exhaust from this website which is in the U.K. . It literally took 2 days to arrive and super easy to install. Comes with remotes to open/close valves . I think I needed to buy extra gaskets that cost me $20 from the company but I think it was still cheap plus I have best of both worlds. Quiet when needed and throaty when I want it.


http://www.ppcgb.com/products/designtek-sport-exhaust-valvetronic-with-200-sports-cell-cats-3606009707

Ibanezgod

Posted ITT because I just purchased a Kline Exhaust, so my BBI will be up for sale as soon as I can get it off. Went with the 200 cell cats, can't deal with any CELs.