Autobahn88 header write up
 

Here in New Zealand, Racing Beat and other US brands are quite expensive to import. Here's an alternative header that represents great value for money.

I found the Autobahn88 header while looking for a budget option on ebay. It was shipped from Zena Racing in Australia. Looks to be a budget AutoEXE copy. I selected this over other cheap ebay options as the O2 bung is located on the collector, not on a primary. Collector internal diameter also matched my midpipe for smoother exhaust gas flow. I installed the header several weeks ago and have been for a few good drives on it since then. Very happy with this mod so far.

Installation
I used the publicly available Racing Beat header installation instructions. Props to RB for the clear instructions. Pretty lengthy install, but straight forward. Jack up the front of the car as high as possible. Don't need to jack up the back. Remove the front right wheel, 3x undercar braces, midpipe (Use silicon spray on the rubber midpipe hanger). Jack up the engine using some wooden blocks across the underside of the oil pan to remove weight from the right side engine mount. Remove the engine mount and engine mount bracket (between mount and block) and remove 6x 14mm manifold bolts. Trace the AGR pipe from the manifold up into the engine bay. It attaches to a large EGR valve. Undo the 10mm bracket bolt under this valve to provide some play on the EGR feed tube that connects to the header so it can easily be moved out the way. Use CRC/WD-40 on all bolts if you haven't taken these off before. I had issues with the WBO2 sensor removal, so completely unbolted OE manifold and carefully rotated it so I could get an adjustable spanner onto the sensor to undo it. The sensor cable should be long enough to do this , just take care not to break it. Be careful not to get the O2 sensor dirty once removed. Treat yourself and use high temp anti seize grease on all bolt threads before reinstalling. If you have a hot girlfriend/wife and she's wearing a short skirt, when you're 2 hours into the job ask her to help by passing some tools while you're under the car. Wrenching has never been better.

Edit (03-06-2014): Use the OE manifold gasket as the one that comes with the header deteriorates due to heat over time and will result in an exhaust leak requiring a 3 hour re-install of the header. :cussing: The rear gasket to the midpipe that is provided with the kit can be used as temps are much lower there.

Fitment Issues
Had to cut down one of the small EGR flange mounting bolts as the bolt hole on the header fouled with the header EGR horizontal collector tube that runs across the top of the header. The EGR horizontal collector tube also fouled against the top of the engine bracket by about 1mm, which was by far the biggest fitment issue. I ended up using a rubber mallet to persuade the engine mount back onto it's bolt protruding from the block. Hoping this won't impact too much on longevity of the header welds. You can see on the AutoEXE header that they've done the right thing and cutaway a section on the top side of the EGR collector tube to clear the engine bracket. If I take the header off again I'll get at it with some tools to flatten it out a bit.
Rear mounting bracket (near flange to midpipe) had the incorrect thread on the bolt welded onto the header, so I couldn't re-use the OE bolts. Not a big deal. For reference I think it uses an M10x1.5 thread on the header bolt, where OE bolts are M10x1.25. I've left the bracket off in the short term, though this will need to be mounted correctly very soon to avoid broken welds. I'll drill out the header bolt thread and use a nut and bolt to rectify.

I'm willing to accept these fitment issues for the money I saved on the product. All of them pretty easy to overcome.

Driving Impression
My car is currently running the AEM CAI and BHR midpipe (res & CAT) with OE catback and OE tune.
I'm not a big fan of loud exhausts - drives you nuts after the first few weeks. With the new header fitted the noise level remains unchanged during normal cruising due to the OE catback. It's definitely louder when you romp on it at higher RPM. The tone is very nice - slightly more crisp without being raspy. It makes you want to drive it hard more often just to hear it. I love the sound quality and volume.

Edit: The following section has been edited for clarification based on feedback..
Performance wise I was expecting minimal gains from this mod after reading many header posts on this forum. The main reason for this mod was to get the OE manifold off the car for a possible turbo project down the track. To set reader expectations for gains from this mod, I estimate around 2whp increase across the full range, with around 4-5whp in the 3.5-5krpm range, and gains tapering off above 8krpm. This doesn't sound like much (and it isn't compared to modifying other cars), but street driving feels a lot nicer as a result, probably due to mid-range gain. I am very pleased with the unexpected performance improvement. When comparing this header with the cost (and shipping) of other performance mods on my car, this is by far the best value for money for me so far. This may be different for owners outside of New Zealand/Australia depending on local shipping costs.

A couple of comments on header design
1. I believe performance gains from this header design can mostly be attributed to the larger internal diameter (ID) of the collector, rather than the tubular primaries. I.e. I'm speculating that a log style header with similar larger ID flange to the matched ID mid-pipe will probably produce similar gains.

2. As with many other rx-8 headers (including OE manifold) the exhaust ports on the header flange are quite a lot larger than the exhaust ports on the engine block. From memory I'm talking at least 2mm around the edge of each port. This "anti-reversioning" design has been used successfully on peripheral exhaust ports to reduce backflow of exhaust gas into the chamber as the port closes. Due to the side port nature of the RENESIS I don't believe this anti-reversion lip is required due to minimal backflow as the exhaust port closes. I'd be interested to hear comments from anyone with experience in port size matching between engine block and header flange on the rx-8.

Edit (11-27-2013): To make this thread easier to read I've removed my questions regarding EGR and turbo manifold design - these were never relevant to this header review, my bad. Thanks to those that responded all the same.

When you say EGR valve do you mean the air injection/pump inlet plate on the exhaust manifold? If so yes its safe to block off if you're not running a cat. Racing beat makes a plate specifically to block off/delete the air pump for those of us running aftermarket midpipes w/o cats.

It doesn't matter this whole endeavor will get you about 2WHP tops. Just use the RB block off plate or make your own.

^do some searching on headers for the rx8. There is A LOT of information posted here of what does not work and what does work. The gains are minimal.

Quote:

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Originally Posted by JimmyBlack (Post 4543898)

this post is relevant to non-turbo owners. I'm saying that this cheap header is excellent value for money compared to the cost/gain of my other mods

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Just highlighting this in an attempt to deter other folks away from commenting about how headers dont do anything.

His point isn't about gains, it is about how it is a cheaper alternative to other name brand headers.

We all know about the lack of gains.

Exactly. Thanks for clearing that up Paimon.

You guys crack me up though. Two turbo owners beating on the (lack of) gains from NA headers. I'm sure I could learn a few lessons from this...

Well actually he is...

When you make the statement:

You are definitely including performance with your assessment and endorsing the product by saying there is an improvement.

Both 9k and I are just saying whatever gain you think you feel is minimal at best. I cannot speak for 9k but the reason I boosted my car is because of wanting more power. There is not much to gain with NA mods. I have seen many configurations on the dyno and getting tuned with not much to show for it.

And yes there is lesson to learn here. Search as I suggested and you will find very detailed discussions regarding aftermarket headers for the RX8. There is a great thread by a professional racer that owns his own team that did extensive testing with the entire exhaust system. With very targeted testing with various headers designs.

when i got headers the gains was mid range power/torque rather then peak HP, it really showed on the dyno and you could feel it too, maybe this is what the OP is referring too.

Its not an egr but air injection from the air pump to ensure the cat doesnt fry on start up. Keep it.

The greddy kit has air injection on the downpipe

Some other header threads here:

boost-brothers-header
bought-obx-r-exhaust-header-had-some-trouble-but-its-working-now (with interesting design discussion)
header-advice

Good read may consider for a slight upgrade in note in my exhuast while using a stock cat.

that the RB blocking plate works wonderfully with :)

LOL...the airpump is actually designed to heat up the catalyst quicker on startup by providing more oxygen

So really it is to fry the CAT quicker :)

That is why it is a good idea to shut off the airpump if the car is flooded :)