Downtube question

[Samiam1017]

I've been looking for that picture of the go cart sitting in the warehouse with the three guys around it (excuse my ignorance, I don't know who they are). But can't seem to find it....but what I'm looking for is the use of the stock down tube. It says on ff website it gets used but I can't see that being used in modified, to me it looked(from what I can remember) like they fabed there exhaust right from the turbo flange. Thx

[Mechie3]

I remember seeing a small adapter tube for offsetting the stock down pipe for axle or frame member clearance. Stock can be used but an aftermarket shorty would be better.

[PhyrraM]

The prototype chassis used a FFR fabricated spacer (about 10" from pics) between the OEM turbo outlet and the OEM downpipe. This is not ideal for flow, but I'm sure the aftermarket will address it soon enough.

[longislandwrx]

As stated, they used an oem downpipe flange and just extended it... not good as the wastegate exhaust slams right into a dead end and has to turn 90 degrees... twice!

If none is provided, i'll be chopping down a TXS shortypipe and doing some "creative" routing.

[RM1SepEx]

any photos? Why not just make a bell mouth adaptor...

[longislandwrx]

they probably just used it because they had some oem downpipes laying around for the flanges and just used some straight exhaust pipe to get the length they needed.

12507

looks like a standard dp might clear but would already be at the back of the car. a shorty might give you room to route it a little better.

here's what i'll probably cut down:

12508


http://turboxs.com/shop/exhaust/229-wrxsti-downpipe.html

[prematureapex]

any photos? Why not just make a bell mouth adaptor...

I was just going to say, make that adapter a bellmouth or a divorced, mate to a gutted stock DP or a divorced aftermarket. Done and done.


No big deal either way. People have made plenty of power with flat-plate downpipes (HKS, etc.), hardly any measurable difference, over a divorced/bell mouth.

[PhyrraM]

The "proper" donor of '02-'07 WRX already has a two piece downpipe with a flange right at the bend where it goes from "down" to "back". I'm fairly sure this is what FFR will base the kit off of because that is where the primary catalytic convertor is located.

Virtually all aftermarket downpipes are one piece, as shown above. I expect these to not work without modification.

Of course, 3rd party vendor will fill any percieved void in FFRs provided design.

[prematureapex]

The joint in the 06-07 DP is in a different location than the 02-05 one.

This:

12509 (older)

vs...

12510 (06-07, which the go-kart used)

Not that a couple inches matters too much...

But the 02-05 DP will certainly result in the exhaus tip extending back a bit more than the DP they used for thr go-kart.


The "proper" donor of '02-'07 WRX already has a two piece downpipe with a flange right at the bend where it goes from "down" to "back". I'm fairly sure this is what FFR will base the kit off of because that is where the primary catalytic convertor is located.

Virtually all aftermarket downpipes are one piece, as shown above. I expect these to not work without modification.

Of course, 3rd party vendor will fill any percieved void in FFRs provided design.

[prematureapex]

Virtually all aftermarket downpipes are one piece, as shown above.


Many vendors make shorty catless DPs configured to mate to the stock 3rd converter. They would, presumably, be a perfectly fine fit for the car. They're cheaper too.

That being said, if you're having the flat plate at the turbo anyway, for the adapter, I'm not sure it makes sense to run an aftermarket DP on the car, vs. gutting the stock DP.

[Samiam1017]

From the looks of that go cart pic. I would think a custom exhaust right off the turbo housing would be very doable and would elimate the need for the extension adapter and down pipe.

[longislandwrx]

I posted the TurboXS shorty . The perrin front section is even shorter and has a cat for those who want to play nice with mother nature.

http://www.perrinperformance.com/subaru/wrx-02-05/exhaust/up-down-pipes/front-downpipe-section

[PhyrraM]

From the looks of that go cart pic. I would think a custom exhaust right off the turbo housing would be very doable and would elimate the need for the extension adapter and down pipe.

That's very true, and I'm sure many builds will incorporate such. I even think that 3rd party vendors will release 818 exhausts.

At this moment, I think the big question is what will the kit include? With the main consideration being the $9900 price tag?

[prematureapex]

I posted the TurboXS shorty . The perrin front section is even shorter and has a cat for those who want to play nice with mother nature.

http://www.perrinperformance.com/subaru/wrx-02-05/exhaust/up-down-pipes/front-downpipe-section

I see the benefit for someone who wants to run a high-flow cat (over the stock cat).

But again, if we're stuck using the extension as shown, the rest of us will be (should be) hard pressed to find a good reason to pay for a shorty DP, as it won't offer any performance benefit over a gutted stocker. The whole point in running a shorty over a gutted OEM pipe is to gain a bellmouth or divorced wastegate...which is negated by the adapter.

What do you mean the Perrin front section is even shorter? Any 02-05 shorty DP is going to be the exact same length, regardless of the manufacturer. An 06-07 shorty will be shorter, however.

Edit: I see. The TXS DP you posted isn't a true "shorty DP" a tleast as the term is commonly used. It needs to be mated with another TXS intermediate pipe depending on the year of your car. It's the same, oddball length as the TXS DP used in their stealthback, etc.

The community normally uses "shorty" to mean a half-length DP that replaces just the first cat of the OEM DP, allowing you to run the 2nd. These have different lengths depending on 02-05 WRX vs. 06-07 WRX.

Those DPs (the true shorties), will leave teh exhaust tip exactly where FFR intended it to be, and will allow you to utilize any kind of support bracket if they provide one at that final flange.

[BrandonDrums]

Honestly, you can take the adapter plate provided, bolt it to the OEM pipe and simply buy a cheap ebay wrx 3'' downpipe (~80 bucks for catless, 200 bucks for catted) and have meineke cut and weld the aftermarket downpipe in the same configuration.

Sounds complicated but it would be a little measuring, 3 cuts and 3 welds and they would have the oem pipe with the provided adapter tube assembled to test against for the whole process which makes it really really easy.

Having had meineke or other local auto shops do similar things, I think you could get all of this done for 50-60 bucks pretty easy. The end result would be a ~$140 3'' catless bellmouth downpipe or $300 catted 3'' dp for the 818. I guarantee a turnkey catless aftermarket downpipe for the 818 will start off in the $400 range. Brand name dp's for WRX's are often that expensive and they have volume.

[longislandwrx]

My apologies for using the word "shorty" interchangeably with "short" That is the name TXS uses for the DP I posted, and I was refering to that specific piece.

In the second reference I was suggesting a short DP, or shorty for that matter would give you more room.




My point was I planned on taking a SHORT downpipe shortening the diagonal portion and rewelding which would give more rear clearance for a custom exhaust exit.

like this:

12511

[Mechie3]

Better pic of the 06/07 joint:

http://i53.tinypic.com/ibc45x.jpg

[BrandonDrums]

My apologies for using the word "shorty" interchangeably with "short" That is the name TXS uses for the DP I posted, and I was refering to that specific piece.

In the second reference I was suggesting a short DP, or shorty for that matter would give you more room.




My point was I planned on taking a SHORT downpipe shortening the diagonal portion and rewelding which would give more rear clearance for a custom exhaust exit.

like this:

12511

That's exactly what I plan on doing and what I'd recommend to anyone looking to drop an aftermarket downpipe on an 818. Buy a cheap 3'' DP, cut measure and weld to match the adapted OEM unit.

Here's a screenshot of a current ebay listing: $66 bucks for a 3'' WRX downpipe in stainless steel w/ free shipping. Ebay links always go bad hence the image instead of the link.

http://i996.photobucket.com/albums/af89/BrandondrumsWRX/DownpipeEbay_zps8c21224c.png