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Discussion Starter · #1 ·
Has anyone done a 4 inch DP to a 5 inch exhaust? If so what are the advantages and are there any disadvantages?
 

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Really there is no need for one... 3" is plenty...

Besides the fact that you need to modify the firewall pretty good to even fit a 4" downpipe in there.
 

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Really there is no need for one... 3" is plenty...

Besides the fact that you need to modify the firewall pretty good to even fit a 4" downpipe in there.
:whs:
 

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Really there is no need for one... 3" is plenty...

Besides the fact that you need to modify the firewall pretty good to even fit a 4" downpipe in there.
i'll third that. because i went from stock right to a 4" dp, i cant say there's any increase in benefits going for a 4" dp over 3"

so, no real advantage, but the disadvantage is the additional hassle to install one due to the firewall and also the turbo exhaust outlet flange.
 

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Discussion Starter · #5 ·
Yeah I knew it would be a pain to do just didnt know if it helped in keeping egt's low and faster spool up
 

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You probably won't notice anything more than what you would notice with a 3" with a stock turbo and injectors... Now if you are looking for 600hp, go 4" dp by all means but you also need A LOT of cash...

Even a 3" dp is 100% better than the stock downpipe.
 

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Discussion Starter · #7 ·
Ok thanks for the input. I already have a 3 inch dp with a 4 inch straight pipe just wanted input if it was worth it.
 

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It's not worth going any bigger... Anything bigger than what you have now is just so you can say you have a bigger dp and exhaust than the next guy...
 

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I have a 3" to 3.5" to 4" DP. I had it coated but they did a $hit job on it and it's rusting. I'll replace it with a straight 3" DP and use an adapter for the exhaust.

Billy T.
[email protected]
 

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I have a 3" to 3.5" to 4" DP. I had it coated but they did a $hit job on it and it's rusting.
My wife painted both her (stock) exhaust systems with linseed oil paint. Not all the way up to the turbo, but as far up the downpipe as she could reach from underneath. This is running stock, so no real high EGTs, but none of it has come off. And it's one of the best, safest-to-use rust inhibitors you can find. Totally safe to breathe in (it's made from flax seeds, for pete's sake!), and lasts for decades on iron ships, and for centuries on wooden buildings in Scandinavia.
 

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some of the oldtimers used to paint the shovel handles at work with that stuff.. haha
OooH Ol-blue you are dating yourself there bud....Heh heh... 50-55ish..?

jrc
 

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OooH Ol-blue you are dating yourself there bud....Heh heh... 50-55ish..?

jrc
way off....... im turning 23 tomorrow.. its just the fact that some of the people at work just wont retire... got one guy who is 71. starting to think that the rail road is all the have? IDK makes me wonder what my future holds
 

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way off....... im turning 23 tomorrow.. its just the fact that some of the people at work just wont retire... got one guy who is 71. starting to think that the rail road is all the have? IDK makes me wonder what my future holds
My apologies....hahhaaa...sorry man wow I was WAY off, just have not heard of someone referencing linseed oil for a long time. Well it's tough out there (now) and the good news is you are young and have time on your side. Due to population demographics (Read..baby boomers...) they will be out of the work force more and more so for (generally) younger folks the opportunities will be significant I think. If I where to do it over I'd head to the patch (oil industry)....the world is based on the petro industry and will be for some time.

Oh and Happy B-day!!!

jrc
 

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My apologies....hahhaaa...sorry man wow I was WAY off, just have not heard of someone referencing linseed oil for a long time. Well it's tough out there (now) and the good news is you are young and have time on your side. Due to population demographics (Read..baby boomers...) they will be out of the work force more and more so for (generally) younger folks the opportunities will be significant I think. If I where to do it over I'd head to the patch (oil industry)....the world is based on the petro industry and will be for some time.

Oh and Happy B-day!!!

jrc
i ment more on the side will the rail road be all i have and be 70 years old and still working when i could of retired 10 years ago but just dont want to be home with my wife.. hahaha

tune in next week for the seson premire of days of our lives, hhah

thats enough d-railing

does anyone have any solid proof od a dyno b4 and after going from a 3.5" to a 4" down pipe. not hear say. SOLID number, scientific proof
 

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I just read on another thread of someone who used a 4" dp and it was like 100* cooler egts blah blah blah.
Derail again, linseed oil paint.. different than the linseed oil finish I used to restore a gun stock? And could it be used on a frame to prevent rust from getting worse than just surface crap?
And all the old dudes here work on the farms when they retire and don't wanna go home to their wives ha.
 

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hahaha yea i read that thread too... but no real numbers to actually make the extra trouble woth it? when i do my manual conversion at one piont in time and i cut my floor out, then might be the time to concider the 4" then....

anyone have roller numbers, or even just a controll in the experimant. same grade, temp, tuck, and pulling the same weight.... and so on. 100* but is it actual or is the temp cooling off and it was actully 70* but rounded up????
 

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BrokeAss
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IMO, would not be worth it. He said he was cutting into the floor and everything to get it in there. I'd put on a 2" body lift before reforming the floor.
A dude with a 2wd obs dually tried to tell me that he had a 4" dp and all he had to do was roll that pinch weld on the firewall. I laughed in his face, and I don't even have one of these trucks. Well I do but its a gasser, I digress.
I asked him to open the hood, he said he doesn't open the hood because there is too much money invested under there, I don't remember what else he said hpop is all I can remember now. I had to walk away.
 

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I asked him to open the hood, he said he doesn't open the hood because there is too much money invested under there
Another candidate for "Posers Say the Darnedest Things!"..... More likely he doesn't open the hood because he couldn't find the hood release if it bit 'im in the @$$. That's gotta be the most laughable line of "reasoning" e-v-a-r. Not to mention that when you spend money on tuning/customizing/whatever your vehicle, it's money spent, not "invested". What, does he think his (real or imaginary) 4" downpipe is earning compound interest sitting under there?
 

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God knows. I was skeptical from the start when he had mismatched tires one was goin flat and most of em were bald as can be, no tailgate and so much junk in the bed it was ridiculous.
Pretty sure he was missing a fuel door too.
Oh and he was flyin a rebel flag with another one hanging in the back window and when he left he had another on from the bed that had a pot leaf in the middle.
 
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