TISF

So when I had my straight pipes I noticed at WOT the car was fast and the power was there but recently I put the borla catback + resonator removed back on and I feel a lot more faster for some reason also me and my friends 370 race around a lot. Before with straightpipes I would pull maybe 2-4 cars on him if I get a good start or if he doesn't jump me . But lately with the borla I've been pulling more of a 4-6 car lengths and we keep going i just keep pulling in him anyone know why? Maybe back pressure ? Or is it just a borla thing lol I doubt it though. Someone elaborate because I'm planning to do a custom quad magnaflow at the rear similar to the Greddy . Oh and one more thing I have ppe headers on both straight piped and now .

Ianx12

Straight pipe exhaust in some cases may cause your car to lose torque.

TISF

If I went and did a custom magnaflow would it be the same as the straight pipes or similar since they're mufflers are a straight through design without much restriction

4everkidd

iTrader: (2)

I think its in your head...

On the dyno every time I open up my E-cutout (direct to atmosphere, no cats etc) I pick up 7hp and torque.

I8ABMR

I dont think its in his head if he can objectively tell that he is pulling harder on the 370.

zapa

maybe the 370s running slower....

RSXiMUS

iTrader: (7)

On a naturally aspirated car, you do need some backpressure to extract maximum power. If the piping is too big, or the system too free flowing you might lose a lot of low-mid range power.

I picked up nearly 30whp peak and over 40whp in the midrange with my Borla system. Power was added from low- high and it got rid of the stock dip in power in the upper rev range. Gained power everywhere, it was an amazing mod and I love it.

Stuno1

What is the difference in terms of power between the X pipe design and the dual pipe design on cat back systems on the F (no headers)? Has anyone actually done a test? I always assumed the X pipe design would result in turbulent exhaust flow and as such creating a more free flowing system would only benefit the power of the car, all be it by very few HP.

I can't see there being much of a difference as long as the pipe bore is the same as the stock pipe. Even if there is a difference I can’t see it being more than 5-10hp and I can’t see someone really feeling that power difference on a car with over 400 ponies.

Stu

MRxSLAYx

Do you think the exhaust you designed is better than the factory system? Its really going to come down to knowledge of air flow dynamics accompanied with time to test a product. Its very possible that your straight pipes are not suited for the power band of the car and slowing you down a bit.

4everkidd

iTrader: (2)

I'm just gonna say it... bull****, one dyno to the next doesn't prove anything. 40HP on a dynojet is 20 on a Dyno Dynamics

And i've owned the Borla before my HKS SSM

I8ABMR

LOL google the question and you will find you are not the only one. There are a few M3 owners with the same issue . HAve you checked for any leaks ?

MGordo

To be fair he didnt say it was on a different dyno....


And:
https://www.clublexus.com/forums/is-...and-24wtq.html

lobuxracer

iTrader: (2)

No engine needs "back pressure." That's what people who don't understand gas theory say.

RSXiMUS

iTrader: (7)

I stand correctly, I guess it stems from my Honda days where everybody would use that word loosely basically to describe the need to "restrict" the exhaust to an extent. The point remains that exhaust gas slows if the piping is too large or the system is too free flowing in the low to midrange, creating a loss of power.

Juanca

iTrader: (5)

Are you talking about an ISF? Can you show a dyno chart to see such a great improvement only from your Borla? It doesn't sound right.