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Old 01-25-2003, 06:41 PM   #1
DrBoy01
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Default The TWE Header question thread

Up till a few minutes ago, I was pretty certain that I was going to buy the Borla header system for its cheap price and ease of installation (no replacing cats, etc.) However, I saw some posts on the TWE, and it got me thinking...

Anyway, I did some searches, and no extremely useful threads came up that answered the questions that I still have. Here they are:

1) I currently have a Stromung catback system installed on my 02 2.5 RS 4EAT. I believe that the diameter is 2.25". Would the TWE Header/cat combo bolt up to that, or would it require welding?

2) Are there any known CEL problems with the TWE system like there are with the Borlas? What tends to cause these problems, if they occur?

3) Has anyone seen a before/after dyno run of the TWE system? Butt dyno comparisons? G-tech? Anything? :P

4) What kinds of shops could install it for me? I'm not asking for specific places, but what types of places could I go to (ie. exhaust shop, subaru specialty place, dealer, etc.) and how much would it cost for installation?

5) Finally, would I have to have the shop relocate the O2 sensor in the exhaust system to avoid a CEL, or is some other sort of placement for the sensor required when the cat is replaced?

Thanks for your help in advance!
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Old 01-26-2003, 01:29 AM   #2
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I currently have the TWE headers and hi-flo cat (2.25" version).

1) It would be almost totally bolt-up. The only thing is that you have to weld a flange on the midpipe end of the cat. They send you that end flangeless for better fit, since each mid-pipe is ever so slightly different. I ended up flaring that end and then putting on a circular flange (like.. one that can rotate around) to mate up with my Brullen 2.25" mid-pipe and then stuck in a double-donut gasket. I think the other option was to hack off the flared end of the mid-pipe and weld 'em straight together.

2) welll.. I have a CEL, but that's due to a different issue. As of now, I don't have a 2nd o2 sensor.. AT ALL. =) Cat inefficiency code. blah. I have a CEL fix on order though. BUT, if you did put in a 2nd 02 sensor, TWE swears on a stack of bibles it shouldn't throw a code.

3) no real dyno... i might do it during the spring. butt-dyno, I can honestly say that it is faster. It pulls hard. like.. WHEE!!! hard. I dunno if its the intake, cams or the headers, but the super-low end torque is somewhat lost.. like below 2K. Above 2Kish things start normallizing out, then 3 ish things starting hinting at goodness. once the needle hits 4K... the tone of the car gets real mean and it hauls ass like a bat out of hell. well.. for a n/a Rs. If it means anything, I think my car is faster now with winter tires that are taller and heavier rims, than it is before w/o the headers.

4) pretty much any exhaust shop SHOULD be able to do it, but i have some issues (personal... due to my previous exhaust) that goin to a semi-suby specialist shop helped enormously.

5) All the 02 bungs are already welded

I have a post somewhere on this club check it out.. plus pics of it.

would I buy it again? YES

Don
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Old 01-26-2003, 12:21 PM   #3
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Are you getting clearance issues Don? Some of those spots are pretty darned close. I'm glad you like them, they are nicely made!

Jay Storm
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Old 01-27-2003, 04:50 PM   #4
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I was just about to purchase the TWE header, then I saw an image from someone and was not pleased. The header was construction from many cut piece s of pipe that had been welded together, instead of bent like shown on the web page.

Can anyone confirm or deny what Im talking about?
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Old 01-27-2003, 06:59 PM   #5
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ciper, I saw the same post, and was equally wondering. Wistful, was that your post? In any case, the image that was floating around before there was a production piece was, obviously, not a production piece. Wistful seems happy with his investment and the product. I'm happy with the MRT system and wouldn't switch to TWE, based on what I've seen and read. However, only Wistful can really comment, as he's the only fellow I know who has TWE's setup.

But the construction did look spooky.
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Old 01-28-2003, 03:02 PM   #6
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yah.. they are not a one-pipe bend job, but instead a multiple bend weld job. That kinda disappointed me when I opened up the box, but then on closer inspection (like within the tubes, whatever I could see) it was pretty darned smooth. Maybe I'm not discriminating enough.

Don
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Old 01-28-2003, 03:31 PM   #7
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wistful: So yours is how all the new units will look? TWE are you listening to this post?

edit: I will not buy the TWE header at that price if in fact the cut and weld design is standard

Last edited by ciper; 01-28-2003 at 06:07 PM.
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Old 01-28-2003, 04:47 PM   #8
DanzBorin
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yeah on the web site they look nice...

what happened?
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Old 01-30-2003, 08:42 PM   #9
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Default TWE header design and appearance issues

The header on our web page is comprised of considerably more welds than the headers we have been producing and selling presently. This was done to maintain proper primary pipe area through a radius that was contrained to less than 2.25" CLR (Center line radius) because of fitment, tuned length requirements (all primary pipes are within 0.100" of each other), and maintainance of stock mounting locations.
WE refuse to compromise design requirements in exchange for cosmetic consesions.
We have recently secured a mandrel tube supplier that is able to produce "inside mandrel" tube in the sizes we require down to a 2" CLR. This eliminates any and all "pie slice" welds on these systems. The 1.75" primary HO header on the website has radii down to 1.75" CLR, which cannot be mandrel bent anywhere that we are aware of (sand bending titanium and inconel may be the exception, but unlikey with out hot forming techniques.
Your efforts would be better spent closely examining the interior of the header (the part your engine sees) and not the exterior. All welds are TIG welded and we spend considerably more time on proper construction than on grinding messy MIG welds and polishing.
It may be noteworthy that many of the "one off" exhaust systems used in formula 1 cars and motorcycles use this method of construction. These designs frequently employ the use of hundreds of pie slice welds as these engineers cannot afford any performance reduction due to changes in primary pipe areas that often occur when forming thin wall tube.

For those of you that have purchased TWE headers prior to our recent design, you may contact Keith Croucher regarding an exchange for our new system (NO HP increase over the old design, but looks prettier!).

We appologise to those of you that have waited for responses to emails and have added personel to expediate this process.

I hope that this has been helpful

Tom Penner
Head of Research and Development
Tech Works Engineering Inc.

PS Watch for the North American Subaru backed Irish Mikes Racing, TWE equipped RS 2.5 in the World Challenge Touring Car Championships on Speed Channel
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Old 01-30-2003, 08:44 PM   #10
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Cool response. Perhaps the images dont do the part justice. From the picture it looked like very sharp angles rather then bends. Can you provide us with high detail images of one recently constructed header?
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Old 01-30-2003, 11:26 PM   #11
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hey cool!
outta curiosity Tom, do I have one of the V1 headers? or a Version 2 header? (for lack of better nomenclature)

Don
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Old 01-31-2003, 12:58 PM   #12
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Default Ver 3 Hdr 2" Radius

Development is being carried out on our Ver 3 Design, in parellel with our headers for the 2002/3 models and for the WRX. As Tom mentioned, we have been able to source 2"CLR Mandrel Bends (see photos). The "shiny" ceramic coated header on our website is a Ver 1. Wistful has a Ver 2 header which has a "flat-titanium" ceramic coating that will handle higher exhaust gas temperatures.

Please email me at sales@techworkseng.com for further questions. I will be handling Marketing and Sales on a full-time basis.

Also, if Nick reads this post, please send me a message at sales@techworkseng.com and inform me of posting guidelines for a manufacturer so that I don't over step the purpose of this forum.

Thanks.

Keith Croucher
Marketing Director
Tech Works Engineering Inc.
sales@techworkseng.com

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Old 01-31-2003, 09:00 PM   #13
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Default

...i like those pictures much better that the ones on wistfuls car....wow those are purdy

spt
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Old 03-07-2003, 05:34 PM   #14
Patrick L
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Keith,

How much are you selling just the header? I am looking for a good header for my SoloII car.

Patrick Lipsinic
STX # 95
Texas Subaru Motorsports/ Kartboy.com
Top Dog Racing
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Old 04-09-2003, 09:26 PM   #15
techworkseng
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Default Better late than...

Top_Dog,

Please check out our new website at www.techworkseng.com for the answer to your question.

Sorry for not getting back to you sooner. I had not been monitoring this post.

Keith
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Old 04-09-2003, 10:33 PM   #16
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Thanks Keith for the update and I really like the website's snazzy new look!

DrBoy (nice to see a fellow doc), the 'Super Stock' (as opposed to the 'High Output') option would suit the 2.25" fitment issue you alluded to. Of course, you'd possibly compromise future forced induction plans at this diameter, in which case, selling your TWE exhaust set up to those put off by the cost of new, would likely be a snap.

Wistful, how's the sound....any loss of that lovable H4 exhaust pulse? This last unknown variable is decisive for me.
Thanks.

- Ken
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Old 04-09-2003, 10:46 PM   #17
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Speaking of TWE, how do their cams compare with Cobbs? Anyone have dyno graphs of a fully modified RS with their headers and cams?
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Old 04-09-2003, 11:17 PM   #18
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I got the MRT headers and they are nice, and for CEL issues, since I didn't put on the rear O2 sensor at the beginning, I've had the CEL, but since I just put it on (O2 sensor wire had to be extended, BTW) it went away after a reset of the ECU. Amazingly right after I get the stupid CEL light fixed, i still need to get my suspension fixed from a accident in the snow

MRT defintely has to be one of the better headers, and im your concerned about the CEL light.

Just letting you know what I went through.
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Old 04-09-2003, 11:25 PM   #19
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I'd rather not get the MRT headers. From what I've seen, I really like the TWE design, and I think they've put more R&D into their product than any other header available for the EJ25 (except, of course, Cobb, which won't be released for a long, long time ).

If the 2nd O2 sensor can be welded in pretty easily, I'll probably consider getting these as long as I'll pass emissions in the state of DE. Anyone know if I would pass emissions with these headers? Would a 2nd O2 sensor be necessary if I JUST ordered the headers and not the high-flow cat? Thanks.

Edit: Er, I mean, with the header & cat combo. Also, would I be able to use the factory gaskets, or would I have to order new ones? Thanks!

Last edited by DrBoy01; 04-09-2003 at 11:33 PM.
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Old 04-10-2003, 02:09 AM   #20
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So lets say I got this header welded to a Random tech Cat. It would just bolt right up tom my stromung midpipe am i right?
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Old 04-10-2003, 02:31 AM   #21
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They have a cat available for the header. I wouldnt weld an aftermarket cat anywhere, Id bolt it up.. That way if it goes bad, order a new one and slap it on..
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Old 04-10-2003, 03:28 AM   #22
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would it be at all possible for someone to post or link to a sound clip of an exhaust system with the twe headers?
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Old 04-10-2003, 11:40 AM   #23
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From a price/performance standpoint, how does the TWE stack up against MRT?
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Old 04-10-2003, 11:52 AM   #24
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well, a few things...

1) the TWEs are ceramic coated
2) TWE customer service is fantastic
3) I dunno how much thought MRT has put into this, but the TWE headers are equal-length and have true scavenging.

I'm itching for the local 4wd dyno to finish, so I can put out some #s for everybody.

Don
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Old 04-10-2003, 12:23 PM   #25
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Quote:
Originally posted by wistful
well, a few things...

1) the TWEs are ceramic coated
2) TWE customer service is fantastic
3) I dunno how much thought MRT has put into this, but the TWE headers are equal-length and have true scavenging.

I'm itching for the local 4wd dyno to finish, so I can put out some #s for everybody.

Don
MRT are more equal length than any headers on the market, and the only one w/ the H pipe that helps equalize pressure...

I have no doubt the TWE are good, but MRT are the original designer of NA only headers...
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