I had just installed 200 cells cat,cargraphic exhaust and also Gruppe M carbon air box into my C2.Thereafter i feel the car very sluggish at the low rev esp moving off from the lite and experienced a little hunting,the exhaust note also sounds like i have a broken exhaust installed.Can anyone tell me wats the cause of this pls.And what can be done to over come it.Tks!

 

Anyone can advice or explain?Do i need to do a DME upgrade to compliment my current upgrades?

 

Yes. I think a DME upgrade would help. Not sure why you are " "hunting". Did you reset your DME? Was the cargraphic exhaust designed to be used with cats. The stock muffler with the cats can sound broken too. Any exhaust leaks? CEL's?

 

should have bought the Fabspeed set

 

send them back, get fabspeed setup.

 

Thinking about this further, I will assume you took the air box out to install these parts. If so go back and check all the connections, you may have a leak or left of the the vacuum line etc.

 

Yes will do that.The Gruppe M looks very good but i think it does not help having the mushroom filter as the element.As for the exhaust,and cats are both Cargraphic so it should not give any prob.But i do suspect the cats as i had experienced lots of low end lag in my Cayenne Turbo S when i had the cat by pass installed.
Rob from DMS will be down here quite soon,maybe i will have him work on the DME to eliminate the flat spots..and you did mentioned resetting the DME,pls teach me how to do it..
Many tks for the contributed advices to ALL!

 

Thats not a good suggestion.....

 

Resetting the DME - Disconnect the NEGATIVE cable on your Battery overnight. you will get a few alerts like PASM etc but all should reset in a few miles. One time I had to stop a restart to get PASM to reset. The other little thing is too raise your windows and hold the buttons in the up position for 5 seconds to get your windows to reset properly.

 

If the low-end is really bad then there is definitely a fault!

A well-designed full exhaust (and the Cargraphic is one of the best) will give increases across the board compared to standard. There will be nuances as to whether the standard headers with the free-flow cats & mufflers will give a little more torque compared to equal-length headers but if you replace a whole standard exhaust with a complete Cargraphic you should get more everywhere.

Don't believe all this bo**ocks about car engines needing back-pressure for torque - it's the worst of old wive's tales. At low rpm there isn't enough exhaust gas to cause any back pressure, even in a standard exhaust. If there was, how could it flow the required amount of gas at full throttle and high rpms?

The fault will likely be an air leak, a faulty lambda sensor or faulty MAF sensor. The Gruppe M is unlikely to be the issue, again it's being asked to flow very little air at low rpms, even at full throttle. That said - if the tube housing the MAF isn't exactly the same diameter as the standard MAF tube, the sensor will give a false reading and the car will be all over the place. Have you tried the car using the Cargraphic but with the standard airbox?

Ian

 

Exhaust tuning on NA motors is generally a trade off. If you see significant top end gains on the dyno, then your low end will suffer. Generally you don't get gains all the way across the rpm range. I would not think there would be a significant enough loss to make you notice though....

 

Tks guys!! Everything is back to normal and better than stock now.I reset the DME by disconnecting the battery terminal for half a day.After which i connect the terminal back and fire the car up.Right away i could tell that the roar from the cold start was different from before,it was meatier,faster and sweeter.After 3mins when the settles down,i took it for a drive.Gone were the hunting,gone were the unsteadiness from the revs.Backed to normal and sounded very good when i put the pedal to the metal,low end was not really sacrificed, the induction note the Gruppe M carbon airbox coupled with the roar of the exhaust sounded like a well orchestraed choir,i am really happy and cant wait to drive her again tomorrow again.Tks to all for valuable advice and may all have a great week ahead!!
Cheers!