Leaky Exhaust = MORE power?

[PooJou]

Hey guys,
Just got a bit of an odd one here - I had my car dyno'd with a leaky exhaust (I didn't realise at the time, leaking massively from the flex pipe) and it pulled a good 115+fwkw

Now, I've gotten that little hiccup fixed, as well as a new cat, and I've dropped like 10kw - my tuner was like "ok what have you done, you've lost a heap of power"

Is there a possibility that fixing the exhaust made it more restrictive and thus, robbed me of power?

The motor is a 4AGZE -> 2 1/4 cat -> 2 1/4 mandrel bent -> Lukey 2 1/4 muffler

[tomvale13]

I'm putting holes in my weiner as we speak.

but srsly, thats a weird one.

[PooJou]

To get an idea of how leaky it was, my mechanic put a rag into the exhaust pipe and the car ran like it wasn't obstructed at all lol

[Smokey228]

LOL Dude, in RE to your delta goodrem is hot link, you have issues I thought they might be porn, but nope!

Next, was it same tuner, same dyno? That always changes things. But other then that, i suppose it is possible, that your exhaust is providing too much back pressure and the leak helped releive it a lil... But then again, a f*ck off big free flowing exhaust wont do any favours either..

Cheers,
Jase

[oldcorollas]

leaking enough to run at idle is not very much gas.
leaking enough to drop 10kw is a fair amount of gas... but possible.
is the new cat a substantially different core design?

[tomvale13]

OR

did you not previously have a cat?

[PooJou]

Same Dyno, Same Tuner - Another dyno showed a significant drop too.

UMmmmm well the old cat was rooted and rattling - the new cat is a magnaflow 2 1/4 jobbie - high flow and all?

But yeah, the only 2 things that have changed exhaust side have been
- fixed flex pipe
- high flow cat.

[PooJou]

LOL Dude, in RE to your delta goodrem is hot link, you have issues I thought they might be porn, but nope!

Hahaha only the best - I bet you downloaded all of it too hahah

[oldcorollas]

everything is "hiflow" these days..... but it still might be shit

[PooJou]

everything is "hiflow" these days..... but it still might be shit

Yeah, but without flow testing every single piece of my exhaust, I have to trust SOMEONE right... and my exhaust place hasn't screwed me once yet (great guys)

That and bloody no one makes aftermarket exhausts for my car anyway

[oldcorollas]

true enough

well.. you could disconnect the exhaust before the cat, bolt on a side pipe, and see if powah goes up

it will but... well.. do it anyway

it could just be that more gas was flowing aroudn the cats core before... not much you can do.. except go for a larger core cat? or just accept it as environmental powah tax

[DQIKST]

check tempreture readings on the dyno graph,
maybe a different gear, different rpm,

[tomvale13]

theres an online place that does performance cats..

I was going to get one to replace the one I dont have.

[IN 05 NT]

fuel used changed? unleaded compared to 98? air temps different?

how long was it between dyno runs? ie 50ks or 5000ks?

[PooJou]

check tempreture readings on the dyno graph,
maybe a different gear, different rpm,

Same gear, same rpm same everything - and it was cooler today too.

fuel used changed? unleaded compared to 98? air temps different?

how long was it between dyno runs? ie 50ks or 5000ks?

Same fuel, BP Ultimate - airtemp was cooler, should run better honestly.

would be a few thousand k's between runs, but i've already listed the things that have changed. Mystified my tuner, who checked the maps again, and confirmed they were very similar to last time.