djdevon3

Stainless Header & Downpipe M2

34 posts in this topic

I know I am digging up an old thread here, but there may be some new relevant info that could be helpful to me.  I've decided to improve the mid to top range power on the 626 LeMons race car. 

 

Currently, I have the original tubular stock exhaust manifold with 2.00" exhaust pipe, no cat, and three glass packs in series to keep noise down.  I've also advanced the ignition timing about 1.5-2 degrees.  The current setup is rather quiet at race rpms and seems to create noticeable back pressure.  The low to mid range power is good, but top end is totally flat.  The car is making peak power by about 4.5K to 5K rpm.  We have been shifting at 5K rpm.  This tune was intentional to improve mileage, extend our driver stints, and maximize reliability.

 

However, we are racing a faster series now and the team is asking for more power so we aren't driving in the mirrors so much.  Therefore, I will be retarding the ignition timing back to 12 degrees btdc, ditching the old exhaust from collector back, replacing it with a 2.5" exhaust with single racing muffler (no glass packs), and possibly replacing the stock tubular header with an aftermarket header.  I know this will wake the car up.  Before our first race, we tried a 3" exhaust with a single glass pack.  The setup was obnoxiously loud, but it made noticeably more top end power.  The mid range felt a little flat, but I suspect that was due to the healthier top end.  I ditched that setup before our first race due to the sound and the likelihood that my team would over-rev the motor.  Now that we want more power from the same motor and we are gonna have to rev the motor some more.  I expect I will bump the shift point from 5K rpm to 6k rpm for the next race.

 

At this time, there are two choices for a header on the FS-DE, the cheap e-bay header and the Bosal.  The cheap e-bay header has an 2" outlet diameter at the collector.  I don't know what the size of the Bosal is.  I suspect it's the same.  The stock tubular header that I have has about a 1.85" outlet diameter at the collector and shorter individual runners.  It's a pretty good looking 4-1 setup with equal length runners into the collector.  The runners are longer than the cast header but shorter than the 4-2-1 e-bay and Bosal headers.  So I assume it's tuned to scavenge at lower rpm than the e-bay and Bosal headers. 

 

Does anyone have relevant information or opinions to share about the current ebay and Boral header specs, performance, fitment, and quality?

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Bosal makes the OE spec replacement downpipe that I went back to after my ebay header fiasco.  That's all I know about Bosal.  Just make sure if you do go with Bosal that you aren't switching out an OE spec for an OE spec.  It would be pointless to waste money on getting the same exact part that you already have.

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I am considering the Bosal header, not the down pipe.  I've seen the down pipe and it won't fit my tubular factory header.

 

The Bosal is a 4-2-1 design.  You linked this same pic of it earlier in this thread.

 

bosa_111-252.jpg

 

My factory tubular header is a 4-1 design and looks pretty similar to this ebay header for the FS-DE Protege (the runners on my factory header are slightly shorter than this one).

 

HDB-MP01.jpg

 

This Protege aftermarket header is likely an option as well.  I expect it would fit since I am hanging a completely new exhaust from the header back anyway.  However, it has a 2" outlet like the Probe/MX-6/626 ebay header and appears to be very similar to what I got.  So I would expect it to perform not much better.

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Bosal are good stuff, but i think they are not produced anymore?

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So necro post here but these things are still floating around cheaply it seems.

http://www.ebay.com/itm/MAZDA-MX6-FORD-PROBE-2-0L-BASE-STAINLESS-EXHAUST-CHROME-HEADER-GASKET-O2-SENSOR-/170723497468?hash=item27bfe9d5fc:g:C9MAAOSw3xJVW5gu&vxp=mtr

It looks the same as earlier in the thread, any reason why it won't fit a 98 with federal emissions? I have just one cat under the car and only 2 O2 sensors, I ask because my flex section is starting to leak and has no outer mesh left on it at all and I had a very positive experience with a similar ebay 'header' on my old 93 Toyota. The whole ebay header is about $30 cheaper than the factory replacement 'J' pipe so I figure why replace when I can upgrade.

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17 hours ago, Bitter said:

So necro post here but these things are still floating around cheaply it seems.

http://www.ebay.com/itm/MAZDA-MX6-FORD-PROBE-2-0L-BASE-STAINLESS-EXHAUST-CHROME-HEADER-GASKET-O2-SENSOR-/170723497468?hash=item27bfe9d5fc:g:C9MAAOSw3xJVW5gu&vxp=mtr

It looks the same as earlier in the thread, any reason why it won't fit a 98 with federal emissions? I have just one cat under the car and only 2 O2 sensors, I ask because my flex section is starting to leak and has no outer mesh left on it at all and I had a very positive experience with a similar ebay 'header' on my old 93 Toyota. The whole ebay header is about $30 cheaper than the factory replacement 'J' pipe so I figure why replace when I can upgrade.

I believe it will fit, but you will be missing the O2 sensor in front of the cat unless it's the one right by the engine, and then just one with the cat. Either way the engines should be very similar and the block itself is identical afaik. So I believe you would be fine.

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I bought one of those this past year and installed it on my '93 626 MTX.  The down pipe was about 1" too long.  It would not fit without cutting an inch out of the pipe.  Others here have had a similar experience.  So if you get one, plan to spend a little money with a local muffler shop to cut and re-weld about an inch out of the down pipe or the pipe on the other side of the catalytic converter.  It should be an easy fix for any muffler shop.

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Awesome. I'll order it when I get back from vacation.  Any difference in sound or difference in highway drone or (I doubt it) difference in power?

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I just stole one for $30.99 with free shipping, I'll update when/if it's installed. I'm really bad about getting back to projects or updating them.

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