Stock Turbo and Stainless Header What are the pitfalls?

[freds]

I hated the rusted heat shields.
I didn't like the exhaust manifolds either
The problem with headers was that the up-pipe outlet diameters were all larger than the stock turbo inlet of 1.75” (Except the Grimm up-pipe which tapers down very nicely)
Looking into the turbo inlet it tapers down very rapidly to the 90 degree turn at the turbine inlet. So I think adding a bit to that rapid decrease in cross sectional area can't hurt that much, since I'm not going for max power.
So I have taken a chance on a cheap SS unequal length header and ground the turbo inlet to a smooth taper with 2.25” start to match the header. I’m impressed with the $114 delivered price head15958159591596015961er, and figure if it cracks I can afford to get it welded up or replaced.

What have I missed that is going to bite me?

[wallace18]

I added heat wrap tape to mine to protect the coolant hoses and oil filter. You can see it on my thread.

[RM1SepEx]

I went with ceramic coated to deal with heat issues

[freds]

I added heat wrap tape to mine to protect the coolant hoses and oil filter. You can see it on my thread.

Yep, thanks. I already have the heat wrap. I'm only going to wrap the headers just before I install them.
My real interest is if there are any knowledgeable opinions on "porting" the turbo, which seemed logical to me.


thanks

fred

[FFR-ADV]

Hi freds,

Where did you find the stainless headers? They look nice! Was the fitment to the heads acceptable?

Cheers!

[freds]

[QUOTE=FFR-ADV;92146]Hi freds,

Where did you find the stainless headers? They look nice! Was the fitment to the heads acceptable?

1. I haven't bolted them up to the heads yet, but with a quick check over the studs they seem to fit fine.

2. Check eBay there are a slew of them being offered. I chose to take a set that has a "slip joint" in what would be the cross-pipe on the stock exhaust, reasoning that that allows for some "wiggle" when fitting. I would be dead nervous about a one-piece fitting both heads perfectly at the same time. I can always clamp/fix/align the joint if I have to. I also chose cheap!
http://www.ebay.com/itm/360503390402?item=360503390402&viewitem=&sspagename=ADME:L:OC:US:3160&vxp=mtr

So that's what I have done and figured at that price, the risk is small...and I'm impressed with the product. I have ground the up pipe-to-turbo flange on the unit as that was less than smoothly finished, but that is all I could see that was necessary.

Hope that helps

fred

[FFR-ADV]

Hi freds,

Thanks for the link. I just ordered mine. Great find!

Cheers!

[305mouse]

I had my turbo ported by deadbolt, which is now no more. At the same time the turbo was coated. It came out really nice. Not sure who I would go to now if I wanted this service done.

[philly15]

I had my turbo ported by deadbolt, which is now no more. At the same time the turbo was coated. It came out really nice. Not sure who I would go to now if I wanted this service done.

blouch or grimmspeed both do excellent porting/polishing/coating work for almost anything also i have a company in tennessee called Proport doing some custom port and coating work on my intake manifold and tgvs ill post up pics when i get them back from there

[FFR-ADV]

I am thinking of using DEI 010126 1" Titanium Exhaust Wrap for my new headers.

There is a nice "how to" on the NASIOC website:

http://forums.nasioc.com/forums/showthread.php?t=2303664

NH requires me to maintain a catalytic converter, so I will be looking for an upgrade to the stock pipe with a (bell mouth or divorced??) catted downpipe. Any recommendations?

Thanks!

[Samiam1017]

I know they say a down pipe is used. Does anybody have any good pics of the setup. Is it modified?

[FFR-ADV]

In the 818R it does not look like the downpipe is modified. But there was also no muffler, just a turn and out the side. From the sound in the track test video it does not sound overly loud, in fact I really like the way it sounds on those fly by shots.

15978

I wonder if the downpipe should also be wrapped. I have seen insulated covers from Perrin:

15979

Keeping the engine bay cool and heat away from the TMIC is a worthwhile effort. Wrapping seems like it might be more cost effective. My instinct is if a company like Perrin offers a thermal blanket instead of wrapping the downpipe there may be an issue, or is it just for convenience? Any first hand experience here?

Cheers!

[Mechie3]

I wrapped the DP in my WRX simply to keep the noise out of the cabin a little. It will also keep some head out of the engine bay (negligible?) but is supposed to speed up exhaust gases by keeping them hot and conserving kinetic energy. I've heard open downpipe wrx's and they're loud. My 3" exhaust wrx is decently loud, with a different muffler it was obnoxiously loud.

[FFR-ADV]

I found a ebay catted downpipe for $180.

http://www.ebay.com/itm/GSP-02-07-wrx-sti-gdb-gda-ej20-ej25-turbo-3-downpipe-with-high-flow-cat-/170905836180?pt=Motors_Car_Truck_Parts_Accessories&fits=Year%3A2004%7CMake%3ASubaru%7CModel%3AImpreza %7CSubmodel%3AWRX%7CEngine+-+Liter_Display%3A2.0L&hash=item27cac81a94&vxp=mtr

Or another option is a no cat downpipe and fit in the cat elsewhere:

http://www.ebay.com/itm/TurboXS-High-Flow-Catalytic-Converter-Pipe-Subaru-WRX-STI-02-07-3-Catted-/271168501811?pt=Motors_Car_Truck_Parts_Accessories&hash=item3f22e6f833&vxp=mtr

http://www.ebay.com/itm/INVIDIA-HS02SW1DPN-02-07-WRX-STI-BELL-MOUTH-DOWNPIPE-/170613023734?pt=Motors_Car_Truck_Parts_Accessories&fits=Year%3A2004%7CMake%3ASubaru%7CModel%3AImpreza %7CSubmodel%3AWRX%7CEngine+-+Liter_Display%3A2.0L&hash=item27b95423f6&vxp=mtr

or is it worth it to go all out with a Perrin:

http://www.ebay.com/itm/Perrin-Performance-Catted-Downpipe-Subaru-WRX-STI-2002-2007-/251242354214?_trksid=p2045573.m2042&_trkparms=aid%3D111000%26algo%3DREC.CURRENT%26ao%3 D1%26asc%3D27%26meid%3D6148770425120158231%26pid%3 D100033%26prg%3D1011%26rk%3D1%26sd%3D251242354214% 26

or TurboXS:

http://www.ebay.com/itm/Turbo-XS-High-Flow-Catted-Downpipe-Subaru-Forester-Impreza-2002-2008-/370774146465?pt=Motors_Car_Truck_Parts_Accessories&fits=Year%3A2004%7CMake%3ASubaru%7CModel%3AImpreza %7CSubmodel%3AWRX%7CEngine+-+Liter_Display%3A2.0L&hash=item5653dc7da1&vxp=mtr

Any thoughts, trade offs or other exhaust plans (come straight back off of the turbo??)?

[papajon1000]

I run a cobb catted down pipe on my legacy gt and it has given me no issue at all. It relocates the cat to right before the mid pipe which I like because it moves the heat to under the car. It also has a bung welded in at the bellmouth for an AFR sensor. It is pretty spendy but if I get another catted downpipe for the 818 it will be a cobb.

[philly15]

im so glad i dont have to worry about cats :) but my favorite down pipe to run is the CNT racing (formerly ERZ Racing) they are pretty cheap compared to most especially the catless DP and they have a bung welded in for a sensor as well as the stock 02 sensor location ill probably be running the catless turbo xs for the 4" diameter as well as since its a two piece you can pretty much do what you want with the exhaust for any custom pipe running

[RM1SepEx]

Any data out there concerning the benefit of bell mouth or divergent downpipes off the wastegate?

I'm sure the flow is better with both... there must be some dyno #s out there somewhere...

I'm remembering a spacer on an 818 prototype moving the downpipe back a few inches... why not just bell mouth the adaptor to a stock or larger downpipe? I do have a nice piece of 3 inch stainless exhaust pipe sitting around

[longislandwrx]

IMHO I don't know if I would wrap an ebay header. the cheaper stainless might not hold up so well to the sustained heat. If you do just check it for cracks periodically. The other issue with ebay headers is that they are often oversized for a more performance look, but actually will hurt performance due to decreased exhaust velocity. Not saying it's the best but for comparison the Perrin header uses a 1.5" primary, I've seen ebay headers much larger. Until about 400+hp a 1.5 primary is ideal. after that a 1.625" primary is used. So measure your header and see what size primaries it has.

Grimmspeed's porting and crosspipe are a great way to get header performance without dealing with the associated issue of headers. If I went this route I would first remove all the heat shield mounting flanges and grind them smooth. (this alone saves almost a pound and makes for a MUCH cleaner look) The coated pieces wont rust and will hold heat much better than thin stainless pieces. However the price is pretty high... about $525 and they are still pretty heavy, (a header saves quite a bit of weight)

port matching everything like you are doing is always a great idea... I remember a thread from a while back where someone's only mods were just light porting and gasket matching his entire intake and exhaust tract. I think he picked up 20 hp

[freds]

IMHO I don't know if I would wrap an ebay header. the cheaper stainless might not hold up so well to the sustained heat. If you do just check it for cracks periodically. The other issue with ebay headers is that they are often oversized for a more performance look, but actually will hurt performance due to decreased exhaust velocity. Not saying it's the best but for comparison the Perrin header uses a 1.5" primary, I've seen ebay headers much larger. Until about 400+hp a 1.5 primary is ideal. after that a 1.625" primary is used. So measure your header and see what size primaries it has.

Grimmspeed's porting and crosspipe are a great way to get header performance without dealing with the associated issue of headers. If I went this route I would first remove all the heat shield mounting flanges and grind them smooth. (this alone saves almost a pound and makes for a MUCH cleaner look) The coated pieces wont rust and will hold heat much better than thin stainless pieces. However the price is pretty high... about $525 and they are still pretty heavy, (a header saves quite a bit of weight)

port matching everything like you are doing is always a great idea... I remember a thread from a while back where someone's only mods were just light porting and gasket matching his entire intake and exhaust tract. I think he picked up 20 hp


Thanks. That is exactly the sort of feedback I was hoping to get as this is my "first rodeo" with a WRX and turbo! (All the other posts have been very useful too).

The header I have bought:
All four pipes are 1.520 ID up to the collector (yes... I used a dial caliper to measure) .
The up-pipe is 2.250
The flange to the turbo is about 2.02 ID. That is flange I had to "port" as the 2.25 pipe joins it at an angle and it requires some massaging. It does not have a swept bend in the up-pipe to get a straight-in connection to the flange. That is the one obvious iffy thing that is apparent.

The head and collector flanges are all approx. 0.37 thick and the pipe to turbo flange is about 0.45 thick and can be massaged/ported fairly decently...not ideal, but not too bad IMHO. Right after that flange and my porting of the turbo inlet to match the 2.02 up-pipe flange, the turbo inlet itself reduces pretty dramatically and then bends to the turbine inlet. So wouldn't the actual velocity into the turbo be the same? Only the velocity in the up pipe is reduced. Of course each individual header pipe has a much longer travel at 1.5 ID than in a stock header.

Anyway, I've gambled and bought one and at that price it not a wild gamble. I also reason that if I have to replace it, it is going to be easier to do on an 818 than a regular WRX. I guess I'll see!!!

Thanks to all.

fred

[longislandwrx]

For that price you cant really go wrong. I would however invest in some oem subaru head to header, and uppipe to turbo gaskets, if the header to uppipe is the std size I would get one of those as well. They are expensive but the junk ones that come with the headers have been known to burn out the first startup. Also If you can get your hands on a stiff pipe brush I would run it through your header a few times to make sure theres no loose slag that might break free and damage your turbo.

[freds]

For that price you cant really go wrong. I would however invest in some oem subaru head to header, and uppipe to turbo gaskets, if the header to uppipe is the std size I would get one of those as well. They are expensive but the junk ones that come with the headers have been known to burn out the first startup. Also If you can get your hands on a stiff pipe brush I would run it through your header a few times to make sure theres no loose slag that might break free and damage your turbo.

Good advice. Tks

[FFR-ADV]

Thanks for the lead Freds,

My Headers came yesterday. Very nice looking!

How do you (or others) plan to button up the cross pipe slip joint?

Something like this? http://www.jegs.com/i/Pace+Setter/766/064300/10002/-1?CAWELAID=1710648395&catargetid=1784155608&&cagpspn=pla&gclid=CN3psIC5kbYCFVGf4AodY0UA2g

Or weld and be done with it?

Cheers!

[freds]

Thanks for the lead Freds,

My Headers came yesterday. Very nice looking!

How do you (or others) plan to button up the cross pipe slip joint?

Something like this? http://www.jegs.com/i/Pace+Setter/766/064300/10002/-1?CAWELAID=1710648395&catargetid=1784155608&&cagpspn=pla&gclid=CN3psIC5kbYCFVGf4AodY0UA2g

Or weld and be done with it?

Cheers!

Hi FFR, I haven't decided yet. I pulled them apart and the fit on mine is quite close. Also the "overlap" length is reasonably long So I might try slotting the larger OD (outer) pipes about 5/8" in 3 places and then use stout Stainless Steel hose clamps to pinch them together. Or perhaps a 1" "slice of a clamp like you show (where the clamping bolt is). I don't like the idea of welding....for later dis-assembly and re-assembly...I like the bit of maneuverability those joints provide.

[Wayne Presley]

Put a V-band clamp on the cross over pipe

[Matty_STi]

Just remember with header wraps they love oil, and power steering fluid, coolant, etc. etc. and then get nice and hot and you've got yourself an engine bay fire.

My suggestion is if you're gonna wrap your headers than some sort of shielding around them to prevent engine fluids from actually ending up on the wrap is necessary.

-Matt

[freds]

Put a V-band clamp on the cross over pipe

Thanks for the tip, they will work!

[FFR-ADV]

Put a V-band clamp on the cross over pipe

Thanks Wayne & Freds. I like this solution.

Next is finding a good way to shield the wrap to avoid fires as Matty_STi suggested.

Thanks!

[Stickshift84]

I also ordered one of these headers. I however was not as pleased with the quality. I found an area of incomplete weld where light can pass through from inside to outside.... ie perfect leaking location. The gaskets are junk. The overall weld quality and tube quality is not the best either. With some extra work they could work but I may not use them. Just figured I would let people know that they are really not that great just for a warning.

[Matty_STi]

Thanks Wayne & Freds. I like this solution.

Next is finding a good way to shield the wrap to avoid fires as Matty_STi suggested.

Thanks!


http://www.zircotec.com/page/new-flexible-ceramic-products/97 one possible suggestion, even just wrapping some thin sheet metal and securing with clamps, aluminum foil or aluminum tape is better than nothing. Anything to limit or prevent the wraps exposure to engine fluids is what's needed.

ex. of the dangers: http://forums.nasioc.com/forums/showthread.php?t=869390 there are plenty of threads about this, some guys have lost their cars, or had serious damage or really close calls.

An alternative is a good ceramic header coating like that from swaintech. http://swaintech.com/race-coatings/

-Matt

[FFR-ADV]

Thanks Matty_STi,

I have seen a picture of a prototype equal length header wrap from Perrin Performance:

16324

I wonder what materials are used in the Perrin Blanket? This looks like it is made with the same construction used for the Perrin Downpipe blanket.

Cheers!

[FFR-ADV]

A little more searching:

http://www.perrinperformance.com/parts/exhaust/exhaust_smallpieces/exhaust_uppipe_wrap/subaru-uppipe-thermal-blanket

"The Uppipe blanket features 3-layer construction. Including an outer cover made from Silicone Impregnated Fiberglass (rated to 500F continuous), an inner layer made of Calcium Magnesium Silicate Insulation (rated to 2000F continuous) and Silica (rated to 1800F Continuous) insulation used to contain the inner layer."

[Matty_STi]

It's still a Fiberglas shell which is porous and will absorb oil. Just need an ignition source and fooom there goes a nice ride. :(

[longislandwrx]

Or fix all your oil leaks and keep an eye out for new ones.

[freds]

Or fix all your oil leaks and keep an eye out for new ones.

+1 for me.