Defined Autoworks Header Install!

[NoDOHC]

I got a few minutes so I test-fitted the new set of headers that I just received from Defined Autoworks.

This is only a test fit, as I still need to port-match them to an exhaust sleeve and build a new exhaust system for behind them. It is my goal that the car will get quieter with this upgrade, as louder will not be a step in the neighborly direction.

I did consider starting the car to hear what they sound like (in spite of the neighbors), but it currently has no radiator or coolant, so I figured it was a bad idea.

Anyway, here are some pictures of the old Racing beat headers before they were removed. They have seen better days, but still functioned fine (except for not making as much power as I want).



The headers that I got (I should say bought, but I barely more than stole them) from Defined Autoworks have an O2 sensor and EGT bung in each header, allowing individual measurement (intended for correcting fuel injector trims to allow for more accurate tuning).

The new headers are almost as long as the old racing beat headers and the presilencer. These pictures give a pretty good idea of the size and the excellent build quality of these headers.




Then I installed the headers on the car. I had to tilt the engine to the passengers side slightly from where the Racing Beat headers had fit, but this only required loosening the nut on the two motor mounts. The transmission shifter barely changed position. Note the position of the stud from the rubber mount in the engine mount:


Other than tilting the engine, the headers fit beautifully. I was pleasantly surprised by how neatly they fit:




The dual oxygen sensors fit like gloves, the attention to detail is phenomenal, The O2 bungs are welded on the inside of a turn, 8 inches from the collector and in such a way that the sensor that must be near the other pipe is furthest away without sticking down and is also below the pipe (allowing better air flow past the sensor and freeing it from the natural convection air path when the car is stopped):


Also to my surprise, the collector actually lines up with the stock Y-pipe. I was not expecting this, as I had informed Logan of my intention to build completely custom exhaust. This is convenient, as I could stick a piece of test pipe in if I wanted to take the car for a quick test spin (which I would if I had a radiator):


The printer at the dyno was on the blink, but I did my baseline run last weekend. The best 4th gear power on the dyno was 218 WHp @ 6800 - 7300 rpm (flat), the best torque was 171 W Lb-ft @ 6000 rpm. I only ran 2 runs in 4th gear (one at the beginning and one at the end) as the engine kept overheating (hence the missing radiator). All tuning was done in 2nd or 3rd.

I am looking forward to the power gain. These headers should flow like a drainpipe.

[RICE RACING]

WTF is up with the BP drilling rig qty of oil leakage under the car???

[FC Zach]

^ ^ LOL, I thought the same when I saw the second to last picture.

Very nice craftsmanship from Defined Autoworks, I would love to buy one of those soon. Great advertisement, thanks!

[infernosg]

Very nice. I assume this is their "4-port" header? Was this "off-the-shelf" or did they make it to a specific length for you?

[project86]

ooh i likey

[diabolical1]

oh boy, i can't wait to see the results of the comparison when you finish putting it together.

[NoDOHC]

The oil in the engine bay was from blowing an oil cooler line, this happened while driving and I limped another 80 miles (stopping occasionally to add oil), so the entire underside of the car was coated. I just hope it helps to keep the rust down.

As far as I know, they built a jig for this header and all subsequent 4-port headers will be identical (Logan- please correct me if I am wrong).

[GoopyPerformance]

Very nice header, Keep up the good work. (Defined autoworks)

[NoDOHC]

Instead of port-matching the headers so that I could put them on the car permanently, I decided to start the car up to see how it sounded.

Now the headers are too hot to touch, although the car was quieter than I expected with open headers. I want to get a video, but the microphone on my camera is non-functional (I think that I forgot to reconnect it last time I had it apart), so it would be a silent video of the engine running.

Running the engine did turn the headers a nice shade of golden brown.


Hopefully pictures of port matching later.

[mazpower]

Beautiful headers, not trying to nit-pick, but your O2 sensors won't last long set up like that. WBO2 sensors need to be at vertical ideally, at least 3% above horizontal so they don't collect condensation.

[NoDOHC]

I had them weld the second o2 sensor bung in.

I have not had any trouble with wideband o2 sensors (other than innovate ones). I put 30,000 miles on my AEM one before it died. It was mounted horizontally (in the racing beat location).

If my O2 sensors die, I will have a good idea what caused it.

Logan: Maybe future headers (with the O2 bung in the collector) should have 30 degrees or so above horizontal.

Anyway: I finished Port-matching the headers.

At first I was going to try to port match to a set of spare junky housings that I had lying around, but this proved to be only a decent clue of what was needed, not really a good idea.

Here are a few pictures of what I found:


It was just about as hard to see what was going on in rear life as it is in the picture.

So I decided to build a cardboard template:



As the exhaust gasket clearly won't work:


I never ported the Racing Beat headers because they were beyond hope:


This picture shows the carbon traces from the brief time that these headers were attached to a running engine:


This shows the intended porting. As you can see, the headers have plenty of meat for porting, especially because the header tubes are inserted and welded at the outside, decreasing the risk of leaks from porting.


This is after porting the rear header:


Completely ported:




Turned out Ok! I suspect that this will help flow considerably.

[GtoRx7]

Looking good glad to see them fit well for you! On the o2 sensors, due to being needed that far back before collecting, there just wasnt any other spot to put them above vertical. I figured the widebands would be used only for tuning however, so moisture collection wouldn't be a issue.

[Mazdabater]

I have no real idea about this stuff, but I always thought on an n/a manifold it was important to have both tubes the same length?? Am I wrong here because the one with all the bends appears to be much longer? Not bagging them or anything just asking out of my own interest

[Silver86]

looking good! lovin that header!

[NoDOHC]

The front and rear headers are the same length, I wrapped them with super high-temp header wrap and I can assure you that they are the same.

I have some more info that I haven't fully digested yet, so before I post anything, I am curious if anyone has tested the exhaust backpressure on an open set of Racing Beat headers at 9,500 RPM. I hope someone has, because I can't find a good way to test mine without drilling holes in them, which I hesitate to do because I want to sell them.

I cobbed a $30.00 tractor muffler up to the headers in true ghetto ricer fashion (hanging down under the car) so that I could take it for a spin (I am still waiting for the mufflers that I ordered). My initial impression on my butt dyno was that I picked up an immense amount of low-end torque (below 2,000 rpm) over the racing beat headers. 2,000 to 5,000 felt about the same (although the tractor muffler is probably creating significant backpressure by then). I couldn't bear to rev the engine past about 5,000 rpm on the street (rotary engines laugh at the puny sound attenuation of tractor mufflers), so I don't know about the high end.

I am running 0.3 AFR leaner at idle and about 1.2 AFR leaner at 1,500 RPM WOT.
About 0.8 AFR lean at WOT at 2,000 RPM, 0.3 AFR lean at 3,000 RPM, about the same above that.

I suspect that I have my tractor muffler to thank for flow restriction at the higher speeds (choking the headers). I can hardly wait until my new mufflers come in.