TopEndS62

Will deleting 2nd cats and replacing resonator with straight pipes result in any gains??? I know all 55k sound better with this setup, but what about power?

The reason I ask is because I deleted the pipes in my E39 M5 and the car felt like it lost the low end torque... I'm just inquiring and interested in the results of those who have done this..
thanks


a dyno comp. would be nice but i understand everything isn't dyno compared.....

Vadim @ FD

Maybe 5RWHP.

jikjak

only 5 whp from removing the secondary cats?
so i guess most of the gains come from removing the primaries?

AZIPOD

5 HP is a lot!!! Back in the Honda days, we spent for a full cat-back exhaust system just to get 5-hp!!!!

TopEndS62

i do agree... 5rwhp is more than i expected if true....

jangy

Maybe 5 is right. Mine "feels"better and I like the SC whine but the primaries are the main gate.

None of this will help if you aren't also pumping in more air. all you do is drop differential psi which is good to a point only. Definitely Stage 5+ before any gains in the exhaust PLUS you will need a custom tune to get that 20hp out.

jangy

5 added to 150 is good. 5 added to 600 is negligent!!

jikjak

i was just expecting more gains from secondary cat delete since primary cat delete made quite a difference. maybe its more than 5whp on a modded car. ill have to dyno again to find out my gains over my current setup after installing 82mmtb and midsection exhaust.
either way ill take all the whp i can get!

TexasSteele

The car feels the same as my e39 m5 did as far as before and after. There is some low end response thats MIA, and it probably frees up some horsepower on the high end. Fortunately the e55 even in stock form can fry tires and has an abundance of low end torque.

AZIPOD

Does the car get a lot louder if the resonator is removed??

lauer87

I believe that opening up the exhaust reduces the back pressure, which will take some torque away, but at the same time let the engine breath alittle better at the top end.

TopEndS62

thats true....

Anybody regret the 2nd cat and resonator delete???

Timeless

I'd be curious on this also.

I believe just the res delete is not going to impace low end torque.

hooleyboy

I picked up a good bit of power from chopping out the 2nd cats. I got a dyno post on the forum some place.

blackbenzz

I don't think you will gain any power from deleting the resonator, it's pretty straight through. The cats and piping are your restrictions and where you can gain power

jangy

No. I still pulled sub 2 second 60 foots and am not good at launching. I have PLENTY of bottom end and want top end. The secondary cats were MINIMAL at either.

TopEndS62

thanks for the responses...