Do I need a downpipe yet?! ---

[alwayscode390]

I have the ultimate chip for stock injectors, 3 map, datamaster, walbro fuel pump, fuel pump regulator, vortec blow off valve w/2 peice flange and intercooler pipe, airfoil, k&n panel filter, johnson ic pump, and a spearco water/meth injection setup. Next I want to redue the ENTIRE exhaust with a cat and 3" pipe with no muffler. Should I get a CUSTOM made 2.5" to 3" cat made and just get a 3" ss pipe made, OR should I go to a 3" dp so I can just run a 3" to 3" cat?

I dont really understand what a downpipe is, what else do I need to upgrade if I go to a 3" dp? Is the dp connected to the exhaust manifold? Thanks ---

***PS I also am super confused about a wastegate, should I be upgrading this too?! I dont even know what they do, lol. I dont plan on upgrading turbos for awhile. ***

 

[MikeRenz]

Re: Do I need a downpipe yet?! ---

a downpipe is the pipe that goes from your turbo to the catalytic convertor...and has the o2 sensor threaded into it. Unless you are going to a larger turbo or are really trying to push some fast times, i really don't see a need for a 3" dp on the stock turbo

 

[alwayscode390]

Re: Do I need a downpipe yet?! ---

Perfect, thats what I want to hear. So it will run good with the 2.5" / 3" setup I was planning to run?

What about the wastegate thing?

I really just need to crawl under the truck and see how it is setup , but it has been raining for a few days now ---

 

[SY756]

Re: Do I need a downpipe yet?! ---

On a stock turbo the wastegate in inside the exhaust housing. You can port it out to make the boost control a little better. The other option is to seal the stock one shut and put an external wastegate on the crossover pipe. But with your setup and you plan on keeping a cat on the truck you should be ok as far as boost control goes. But porting the stock wastegate can't hurt. It just takes some time to do. Also, I agree with Mike on the DP issue. I would wait on a 3" downpipe until or if you ever do a turbo upgrade.

 

[alwayscode390]

Re: Do I need a downpipe yet?! ---

You guys answered my 2 questions perfectly....thanks for being patient with a noob ---

 

[Flyin Ryan]

Re: Do I need a downpipe yet?! ---

there's been plenty of 11 second trucks running the stock dp so it's not needed to be fast but most is somewhat a bottlekneck with bigger turbos

 

[alwayscode390]

Re: Do I need a downpipe yet?! ---

I getcha ---

 

[HotRudyRod]

Re: Do I need a downpipe yet?! ---

I read at another post that insulating the turbo, crossover and DP does shorten the spool up times wonderful and nets more power than the 3" DP on a stock or slightly bigger turbos.