tuning with open downpipe.

it will affect your tune if you throw an exhaust on afterwards

ryan89crx said:

it will affect your tune if you throw an exhaust on afterwards

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well i understand that, but what your saying is dont worry about it until i do decide to run exhaust?

I just want to make sure that the car would have an efficent tune and not bee too rich at certain points like described in the link to the pgmfi.org thread. I dont really see why running open downpipe would affect the tune in anyway, but when i saw the question and the problem he was having, i thought i would ask.

But yes, if i do run exhaust i will definately have it retuned for it.

thanks for the help man. :TU:

Im going to be running a 3 inch open d.p…. was going to go with 2.75 inch straight back to a apexi turbo muffler BUT when I seen the 29 whp my buddy jeff got on his gsr turbo from going to 2.5 inch exhaust to a 3 inch open d.p that changed my mind right there….

93 red ls said:

Im going to be running a 3 inch open d.p…. was going to go with 2.75 inch straight back to a apexi turbo muffler BUT when I seen the 29 whp my buddy jeff got on his gsr turbo from going to 2.5 inch exhaust to a 3 inch open d.p that changed my mind right there….

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thats exactly why im running open dp. i hope to hit 300whp, so i know it will definately benefit me.

thanks for the input

Im running an open dp, not really that loud but it is worth it. You can hear the turbo wind all nasty :TU:

the link you posted sounds like it might have something to do with the location of the o2 sensor, although usually that will be a false lean reading.

but he might not know what he's doing, still getting used to tuning.

if you get it tuned without exhaust, then that is what the tune is for. i would write two chips when you are getting it tuned. write a chip for your open dp, then put exhaust on it and get another tune for that. that way, you can run exhaust until you go to the track, and then just unbolt it and run just the dp. i ran with no exhaust for a while and it got old. after i put the exhaust on the car, it was so much more pleasant to drive. since it is a turbo car it isnt as loud as a na car running upen header, but it still makes some noise.

^I'd thought about doing that, but since I'd really like to run an E-cutout I'd like to be able to have two maps to be switchable at a moments notice. What exactly would be needed for that? Is there such a device?

kyle h. said:

the link you posted sounds like it might have something to do with the location of the o2 sensor, although usually that will be a false lean reading.

but he might not know what he's doing, still getting used to tuning.

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id say its due to his DP location

I turboed my DA and pretty much have the dp stopped right where the oil pan meets the block.

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the exhaust is being sucked back into the snail due to the fact that the DP isnt ran under the oilpan like it should be. less oxygen in the motor due to excessive exhaust funes = rich

run your DP back as far as a stock exhaust mani would go and you wont have a problem

that and having an open down pipe will allow the turbo to spool faster

yes sir open downpipe will allow quicker spool... all the back pressure is made in the manifold so faster spool comes with a shorter exhaust.... AKA- the open Down pipe... a open down pipe when tuning is a tuners worst nightmare, i hate kids that come to me with een open header because while the exhaust is flowing out air from the outside is passing by and does make a mistakable lean condition almost everytime, i dont run the sensor less than 12 inches away from the end of the exhaust... but just so u know u can even get a mistake on the WB between brands, my AEM UEGO reads leaner than my PLX and that show leaner than my Innovative, in my eyes the innovative is the only one to trust since it recalibrates everytime you need to for every new car... GL homie...