Any benefits to running dumps....?

[AUDILUX]

I have an electronic dump on my car and although I thought I noticed a difference doing highway pulls against my friend with dumps open vs. closed, I recently had the car on the dyno and it showed no difference with the dumps open vs. closed. Anyone else have any input on whether or not there are benefits to running dumps? Thanks.

[Das General]

MarkP showed gains of 40whp with dumps, on some dynos.

[Trigger Happy]

It depends on where your dump is. Obviously if its after cats or mufflers its going to be much less effective. Also turbos, exhaust diameter and configuration make a difference. For example if you add a dump after the DP's (assuming the DP's are fairly free flowing ie 3" or catless 2.5") and you have a stock exhaust opening said dump will give you a pretty good gain. Obviously this is an extreme example, but the concept still applies. Either way you should see some gains. I would say you not seeing gains was from either heat soak or some other variable. Bottom line is dumps will give you an increase as long as they are before the majority of the restrictions in the system.

[Raacerx]

Yes there are huge benefits to running dumps. Too bad it sounds like crap to me. If you didn't see increases on the dyno, then you were either heat soaked, or your dump is not before the cats. If you dump with no cats, you should see a 20-30whp increase minimum.

[anger]

Yes there are huge benefits to running dumps.

have you known anyone to prove their car was faster? and not just louder?

[Raacerx]

have you known anyone to prove their car was faster? and not just louder?

Yes. I have seen countless dyno's that show 30+whp improvement. Obviously, if you are running 3" downpipes with no cats and a 4" exhaust, the improvements from dumps would be relatively minimal. For someone going from catted downpipes and a restrictive exhaust to dumps on a Stage 3 should see huge increases. Its simply physics.

[anger]

i have seen a ton of cars pull up to the dyno, drop the exhaust, and put down more power. none actually go faster.

[Raacerx]

i have seen a ton of cars pull up to the dyno, drop the exhaust, and put down more power. none actually go faster.

ah. now i got what you are saying. and yes, I have seen cars pull quarter second better FATS times with dumps. Beyond doing quarter mile racing, I am not sure how you would measure the benefits. Dyno, FATS... seems to be pretty good evidence.

Can you please tell where you are running the dump?

[jibberjive]

Marc (10sec) used to always run faster times in the 1/4 mi with no exhaust. Same with Jay/Dan at JHM when they did cutouts or upgraded to a huge exhaust. Those still are the fastest cats around (or rather not around.)

[AUDILUX]

My dump is after my gutted cats (where the 2.5" downpipes meet 3" exhaust w/ 2 resonators). Again, I noticed a difference on the highway pulls (my friend's stage 3 would be neck and neck with mine when the dump was open, but he would pull when it was closed (he was running more boost, which is prob why he pulled when my dump was closed)).

But, the dyno showed no difference.....

[TheDarkness]

i always just drink a big cup of coffee in the morning, helps me out right quick!

[WMi_S4]

Here is a link to Tweets dyno thread:http://www.audizine.com/forum/showth...to-guess-right!!!

IIRC, he did a few dyno pulls with his dump closed and the result was 20whp less and 28wtq less (this is on E85 but I would assume 93/race gas would net similiar gains/losses w/ the dump opened and closed).

His dump is right before his X-pipe begins on his custom cat-back