BMW x5 4.8is (e53)- X-pipe or Straight Pipe?? PLEASE HELP

[pnoyako85]

^^^^ yup agreed..cnt view too man...

[skunkd]

Ok I'm gonna have a solid compare video up next week or so to settle this same car, same cam... etc.

Right now I have a 4.8i with cats but no resonators and no mufflers with an H-Pipe straight out.

Next week (tuesday) I'm switching out the H-Pipe for an X-Pipe only.

We will see the difference this one single variable makes shortly.

until then this is my current cat's to h-pipe only no res no mufflers videos.

Rev with cats and h-pipe only:
https://www.youtube.com/watch?v=-f6uvN181yA

https://www.youtube.com/watch?v=lGL7oLHbp6w


Highway cruise w/ cats and h-pipe only:
https://www.youtube.com/watch?v=CtR7fVZwyvc

[Nick P]

Normally, even stock 4.8 N62s have about 230-235 whp or like 330-335 bhp instead of 350 claimed bhp. I saw a dyno chart with 225 whp AFTER remapping. On the same dyno my 4.6is with Hartge headers cats delete and "sporty" resonators showed 242 whp with 95-100 hp driveline loss but immense 500 nm (368 lb fts) of tourque only at 2700 rpm, the N62 4.8 could acchieve only 440 nm or 325 lb ft.

In near future I'll put the cats back (because supercharged engine needs even more back pressure) and will do another measurement before supercharger installation.

Removal of resonator (or even both - muffler and resonator) on n/a engine will cost you a loss of another 20 whp, so the result will be a loud car wich sounds like 600 hp, having like 60-70 hp less, than manufacturers claim.

With very few back pressure you flush the cylinders with the fuel-gas mixture, so the burning process is wrong and also your cats won't last long due to very wet AND air-rich exhaust gases, which will burn in exhaust and not where they supposed to burn. The lambda sensors first will read wrong parameter and then also die, because of overheating.

If you considering of removing the parts of exhaust you have to correct the lambda values AND shift the lambda sensors further from the engine (but still it will be just a give a ball park action with very iffy result).

So IMO if you're considering a exhaust tuning the only appropriate way is to play with the muffler.

[pnoyako85]

Nick..so your Advice is to get a High Flow Cats and Resonators for E53's?.....

[SlickGT1]

Originally Posted by Nick P

Normally, even stock 4.8 N62s have about 230-235 whp or like 330-335 bhp instead of 350 claimed bhp. I saw a dyno chart with 225 whp AFTER remapping. On the same dyno my 4.6is with Hartge headers cats delete and "sporty" resonators showed 242 whp with 95-100 hp driveline loss but immense 500 nm (368 lb fts) of tourque only at 2700 rpm, the N62 4.8 could acchieve only 440 nm or 325 lb ft.

In near future I'll put the cats back (because supercharged engine needs even more back pressure) and will do another measurement before supercharger installation.

Removal of resonator (or even both - muffler and resonator) on n/a engine will cost you a loss of another 20 whp, so the result will be a loud car wich sounds like 600 hp, having like 60-70 hp less, than manufacturers claim.

With very few back pressure you flush the cylinders with the fuel-gas mixture, so the burning process is wrong and also your cats won't last long due to very wet AND air-rich exhaust gases, which will burn in exhaust and not where they supposed to burn. The lambda sensors first will read wrong parameter and then also die, because of overheating.

If you considering of removing the parts of exhaust you have to correct the lambda values AND shift the lambda sensors further from the engine (but still it will be just a give a ball park action with very iffy result).

So IMO if you're considering a exhaust tuning the only appropriate way is to play with the muffler.

Amen to this. I've done all this exhaust screwing around on previous cars. Enough to realize that this is just noise, and nothing positive performance wise. Every time I did an exhaust mod, I had it dynod. I lost power every damn time. Only improvements you can get, is with big buck exhaust systems, that were tested, tuned, and dyno proven to show extremely mild results. Really not worth it. You wanna go faster, lose some weight. You want people to look at you go slow, screw with your pipes.

[TwinsPoppa]

Originally Posted by pnoyako85

Nick..so your Advice is to get a High Flow Cats and Resonators for E53's?.....

No. What he's saying is if you're messing around with the exhaust, especially for performance purposes, use mufflers (so that you have enough back pressure and don't lose performance).

Even just for better sound, use the mufflers.

Basically, if your X is mostly stock or not heavily performance modified. changing the stock exhaust is probably going to net you lost power.

I have stock exhaust but replaced only the resonator with an x-pipe for the nice sound - didn't care too much about the performance hit.

If you don't have at least headers, you probably don't need to mess with the stock exhaust for performance gains.

That said, who doesn't like modding?

[pnoyako85]

oh i see.....although now..i Need opinion..on changing Cats......what is the best out there?>>............i may need new cats..and looking around and there alot of them out there..i heard FD 200 Cell are good...but what is really good ?..

[TwinsPoppa]

Originally Posted by pnoyako85

oh i see.....although now..i Need opinion..on changing Cats......what is the best out there?>>............i may need new cats..and looking around and there alot of them out there..i heard FD 200 Cell are good...but what is really good ?..

Sorry, I have no clue. However, you can't go wrong with the stock ones.

We all know what can happen when you start modding. Sometimes its tricky trying to make new things work together with the existing - the fit, performance, looks, reliability, etc.

Especially if you're the first one doing something.

[Nick P]

Originally Posted by pnoyako85

oh i see.....although now..i Need opinion..on changing Cats......what is the best out there?>>............i may need new cats..and looking around and there alot of them out there..i heard FD 200 Cell are good...but what is really good ?..

The N62 has Euro 4 emission standards, so 200 cell aftermarket cat could be risky in terms of passing the emission inspection. Normally, the afermarket high-flow cats could be used on cars having Euro 3 emissions standard, but I've heard, there's no such a thing as emissions control in many US states.

Since my X5 is registred in Russia, I did remove the cats, but installed some simple devices, which supposed to homogenise the exhaust flow, so the back pressure was there and I also installed very simple devices insted of stock resonator. Afterwrds my engine was remapped and I haven't seen any significant gains even with very rare Hartge headers exept for a huge torque increase at low rpms, but I suppose, this torque increase has nothing to do with exhaust, but rather with software, which had very mild tune especially at low rpm to spare the weak gearbox.

First I got measured 323 bhp with approx. 100 hp driveline loss having Hartge headers, cat-dummies, and these so called "sporty" resonators (which are basically tubes with some mesh inside around).

On the dyno chart you can see the huge torque increase after tune (more than 100 nm (75 lb ft) on some rpms.

Now with manual gearbox I have even less driveline loses and so more whp and also about 50 kg (110 lbs) less weight.

Next year I'll put the 200 cell cats and will do another dyno session.

My message was just not to mess around with exhaust, because the stock one is properly designed and tested in interaction with controlling electronics.

[James 4.8is]

Originally Posted by LeMansX5

I have X-pipe. There are quite a few threads here on X-pipe install. I had also posted one on the exact X-pipe to get.

Where is the best placement for the X-Pipe? Front, middle, back? When comparing with the resonator. And which X-Pipe is the best? Here is a Picture of the only X-Pipe available where I live. It’s a Simons U9063XR 2 1/2 inch. Your thoughts are needed!