My 6g74 tt build

Rear precat delete is pushing back into the subframe which is also pushing the downpipe back into the subframe. Rather than take it off and try to fix it some more, I'm trying to make it work. Getting an old oem rear precat from another member just in case. I've been tempted to trash this thing a few times already. Maybe even melt it down.

Hit the edge of the subframe with a grinder to try to allow just enough room for it to bolt up.
Attachment 5548

Attached the rear section of downpipe, then the front section. Ended up with this humongous gap under the oil pan.
Attachment 5549


This thing has been a real PITA. I bet I would have had better luck getting my old n/a downpipe to fit, lol

Another vid or 2 coming

if you have a local welder (sounds easier than it is a lot of the time), cutting that downpipe and welding on an extension piece of metal would be quick, easy, and less than $100. thats definitely what i would do.

under $50 at exhaust shop

I have an oem rear precat coming. Pretty sure that will make a drastic improvement. Not sure I want to make any permanent changes until after I try that.

Right now it needs to be lengthened on ends toward front and rear manifold. That may also help the center gap. Even with spacers added, it's touching the oil pan so it needs to come down a little lower. I believe they're angled slightly inward and if so, that will help. Between that and the rear precat angled properly, think I"ll probably only need a single spacer to join the sections.

Finally bled brakes, so I guess my ABS delete is actually finished now :p

Drove it for about a minute, just to the end of the street and back. Testing brakes and boost gauge and checking for leaks.
Tightened up one of the oil cooler lines a hair more. Brakes still have a little air in the lines from the ABS delete.
Topped off power steering fluid. How does a mechanical gauge not work? lol

Quote:

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Originally Posted by n2nsanity

Rear precat delete is pushing back into the subframe which is also pushing the downpipe back into the subframe. Rather than take it off and try to fix it some more, I'm trying to make it work. Getting an old oem rear precat from another member just in case. I've been tempted to trash this thing a few times already. Maybe even melt it down.

Hit the edge of the subframe with a grinder to try to allow just enough room for it to bolt up.
Attachment 5548

Attached the rear section of downpipe, then the front section. Ended up with this humongous gap under the oil pan.
Attachment 5549


This thing has been a real PITA. I bet I would have had better luck getting my old n/a downpipe to fit, lol

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your 6g74 right?? taller deck height = heads further apart = your downpipe gap???

Not this much of a gap, lol.
For one thing, I've had this engine in the car for over 2 years and 2 different downpipes lined up fine (1 oem, 1 aftermarket)
Also, the proportion isn't even. It's like 1 inch taller which equals about 1/4" in size added from front to rear.

My guess it's a combination of these 3 things.
Horrible fitment of 3sx rear precat delete = 2" off
6g74 = 1/4" off
m2 downpipe = 3/4" off

funny how the name brand part is the one thats fucked up the most...oh yeah, according to stephen from 3sx its because they can't find welders/fabricators in the US so they went to china.

best excuse for just being cheap that I've ever heard...

Thats like saying, I couldn't find any good seafood on the west coast so I went to Mcdonalds to get a Filet-O-Fish and they gave me a cheeseburger and so I said, meh that'll do fine!

Yeah, I test fitted the rear pre cat delete after fitting the stock one. It is probably 1/2 inch off where it is supposed to bolt to the stay. The O2 flange is effed up which I knew about. Plan now is to get rid of the POS and gut the stocker instead.