3'' plenums

star73 · Nov 20, 2016

How come all the aftermarket intake plenums I see won't fit OBS trucks? I have stock turbo and banks intercooler. I thought I seen someone on here had made it work. Just need E99 spider?

Magnum PD · Nov 20, 2016

The early 99 spyder will be the only one that will work with the stock obs turbo. If you want to put 3" intake on, that's gonna take some fabricating. I did it. I cut the SD spyder into and used the Banks turbo outlet. Had pics but webshots is no more.

gnxtc2 · Nov 20, 2016

3" plenums fit but you need the flat ones that Irate sells. To use the OBS spyder, you need to get 2"-3" reducing hoses. I've previously ran 3" plenums with a OBS turbo.

Billy T.
[email protected]

old man dave · Nov 21, 2016

You can use a stock SD 3" plenum if you dent it a bit on the drivers side for turbo clearance for the stock OBS turbo. Passenger side no problem for either stock or aftermarket plenums.

danielzink · Nov 21, 2016

I'm running Irates 3" plenums on an E99 in my 97:

superpsd · Nov 21, 2016

I'll be ordering a set of these very soon.

gnxtc2 · Nov 22, 2016

Where is the weld? Any pics showing how the bottom is machined for the round tube?

I found a flaw in these flat plate style 3" plenums and it's an easy fix prior to machining.

Also, the later heads have extra intake bolt holes.

Billy T.
[email protected]

superpsd · Nov 22, 2016

They are advertised as billet plenums.

gnxtc2 · Nov 22, 2016

Don't matter billet or fabricated. They all have a flaw if not made correctly. I believe Irate corrected the issue on theirs.

Billy T.
[email protected]

mattman347 · Nov 22, 2016

Yeah, we have not had issues with ours sealing up or cracking. They are on sale too... http://www.iratediesel.com/irdie/product/idp-plenums/

97powerstroke · Nov 22, 2016

What's the flaw if not made correctly?

superpsd · Nov 22, 2016

Cracked welds maybe?

m j · Nov 22, 2016

looking at the image on irates site it looks like they closed the opening up to better fit the heads.
older version (like I have) can be tricky to seal as the late was cut to the 3" inlet tube size.

I like the new webstore, looks good

gnxtc2 · Nov 22, 2016

Billy T.
[email protected]

m j · Nov 22, 2016

superpsd said:
I'll be ordering a set of these very soon.

may or may not be an issue but you wont be able to install or remove those with the front cover on if the forward bolt hole is not cut

superpsd · Nov 22, 2016

I will keep that in mind when I check them out up close. There is also the Riff raff plenums and I see they don't require sealant as they are o ringed.

mattman347 · Nov 23, 2016

m j said:
looking at the image on irates site it looks like they closed the opening up to better fit the heads.
older version (like I have) can be tricky to seal as the late was cut to the 3" inlet tube size.

I like the new webstore, looks good

Yes, we did get more material there for sealing and have had no issues.

Although, I run an older set on my truck without issues either, just had to pay attention sealing them up.

Magnum PD · Nov 24, 2016

gnxtc2 said:
Billy T.
[email protected]

I took that "stud" out and smoothed the sharp edges going in on mine.

gnxtc2 · Nov 24, 2016

The issue is the sealing area at the bottom, it's maybe 1/8" wide. There is a pic floating around of how wide the area is.

Billy T.
[email protected]