obs downpipe

obspsd

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Does anybody have a obs downpipe that is bigger than 3 inch that they wanna sell or know anybody that could make one
 

DZL JIM

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FWIW 500+ hp through a 3" dp has been done for years.

Anything larger than 3" will be full custom requiring a lot of custom work to the firewall. If you have the skills to mod your firewall that much, then you can make your own dp.
 

obspsd

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I got ahold of Jake at irate and i think I'm gonna try his 3 inch dp. I'm sure it will flow a lot better than my $hitty home made dp
 

fatsix

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I got ahold of Jake at irate and i think I'm gonna try his 3 inch dp. I'm sure it will flow a lot better than my $hitty home made dp

Yeah, I can see that being the restriction. Optimum taper is 7 degrees for a transition in pipe size with 4 to 12 degrees acceptable. I think you had 45* on the top right at the outlet ? I will be cutting my firewall.

I believe your exhaust wheel is 92mm? Which is a 3.62" wheel which tapers out to a 5" hole covered by a 3" pipe. Commonly used calculation for optimal downpipe sizing is exhaust wheel size x 1.25. For you that would be 115mm or 4.52". Just saying...

3.5" is good to 750 hp.
 
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old man dave

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Ricer shop in my area would do a 4" downpipe and ovaling it down to about 3.5" for clearance in an OBS for around $400 or so but has to have the truck for a week.
 

obspsd

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Yea there's a rice shop in my area that's pretty good too I just wasn't really trying to pay 400-500 for a dp unless i have to
 

obspsd

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Unfortunately i know this, that's why i said unless i have to
 

baderic03

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My s475 with jakes down pipe. and you deff need to massage the firewall

2cf1ed62.jpg

3e24513a.jpg

1863f5f4.jpg
 

97powerstroke

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Hypermax has a good downpipe with there mount kit. I didn't have to massage anything it fit right in. Looks pretty similar to jakes.
 

baderic03

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The amount of firewall massaging to get a 3.5in down pipe on a obs with a s475 charger is retarded not worth it
 

Cat_rebel

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How much massaging is needed to get a regular 3" down pipe in there for a stock turbo?

Depends on the truck, mine needed massive amounts of swearing & beating to fit. Makes me wish I never took the hood stack off every time it rubs. Also get pissed off every time I install a 4" DP into a SD in about a minute with no modifications to the firewall/down pipe. :mad:
 

6.0 p-stroke

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I just got the engine out of my '96, after seeing the stock down pipe it will be going back together with a 3" dp. I just don't know exactly how much to "massage" the firewall without the engine in for reference. Anyone have any pics that might give me some ideas?
 

baderic03

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I can get a 3in diamond eye down pipe into a obs from pulling old to new in in about a hr. key is a good pry bar
 

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