Car is running at its best at the moment. The air straightener has smoothed out the idle and acceleration is a lot smoother, no more head slamming on the back rest.

Went on our cruise up a mountain and temps hovered around 80 to 90c with a/c on and on the highway it dropped to around 70c with ambient around 18.

If our winter gets any cooler I may need to block off one of the oil coolers.

Waiting for BHR coils to arrive then back to the tuners. At the last tune they retarded the timing so I may now look into advancing it a bit to see if we can recover some of the lost power.

 

Checked my spark plugs and they looked good. Light brown powdery soot along the spark plug edges that was easily cleaned with a rag. Looked into the spark plug hole with a torch and the rotor did not have any carbon deposit.

So the tune must be spot on for it to be running so well.

 

Went to the track today and it started well. Unfortunately, I think the car is running very lean. I believe that the tune was based on the aeromotive pump and now I am back to stock so this could have somehow effected the tune.

The exhaust tips looked very white after the first run...usually it takes a while for the carbon to burn off. I also started to experience hesitation under heavy load. During my third run I ended up with a code P0037 which indicates a dead rear o2 sensor. I believe it was caused by the car running lean and the exhaust must have overheated.

The oil temps where in check as it did not exceed 100 deg

 

Nice to hear~!

 

BHR coils have arrived so the car will go back to the mechanic for installation together with new Walbro pump, new O2 sensor and a retune.

I also remembered that I had installed a new catback as well so it could have also been a factor in the lean condition at the track.

Another observation after the track day was that I am getting far less blowby into the catch can. I wonder if cleaning all the carbon off the rotors has helped improve seal performance.

I am quite surprised by the resilience this motor has shown despite the punishment it has faced.

 

I had a bit of oil leak after the track day last week as well as running lean.

The oil leak seemed to be coming from the around the omp side of the engine so I decided to investigate. To my surprise I found that the vacuum line going to the omp had come off and it was quite evident that oil had leaked from the exposed line.

Does anyone know if the oil would have come from the OMP or the possible blowby from the vacuum line?

 

Drove the car to work and it cannot hold idle and runs really bad below 3000rpm. Keep getting the P0037 code and the odd lean code.

I will have to reinspect my vacuum lines again. Surely the burnt out 02 sensor could not be responsible of such a poorly running engine. I will also check the plugs .

 

I took the vacuum pipe out of the omp vent as it was causing major issues on the drive to work. Drove to work today and it runs better with the vacuum pipe disconnected with next to no vacuum at idle so that pipe needs to get connected somewhere.

Also noticed an exhaust leak near the cat so I will investigate this tonight.

 

Drama over, it turned out that there was a boost leak from the intake plenum. The vacuum hose that popped off was supposed to go into the OMP breather.

I am not keen on vacuum and boost applied to the breather pipe so I may look at getting this eliminated and blocking off the vacuum pipe. Hopefully this will prevent a repeat of this pipe popping off at the track.

The vent pipe from the OMP needs to be plumbed back into the intake as per the stock configuration as you do not want to dump metered air to the atmosphere.

The Walbro pump has been installed and seems to run well. It makes a bit of noise at start up however, it is not noticeable at other times. This is the first time I have heard the pump at work. The stock and Aeromotive where quiet in comparison.

Engine shows over negative 12lb vacuum at stock idle which is the best reading I have had for a while. Another strange discovery was that the rear O2 sensor had a dent and the post appeared to be bent. This indicated it has been hit by something at high velocity while I was at the track. this caused the P0037 cell and now that the sensor has been replaced the cell has disappeared.

The motor has sustained a lot of abuse from track and boost leaks however, it is still going strong. Would have loved to get it back onto the dyno to check the tune, unfortunately it was not possible as they dyno was busy with other jobs.

I will take some logs and check it myself.

 

OMP vacuum pipe removed and now plumbed to vent on oil filler neck, second vent on oil filler neck now to intake.

I initially had the vacuum pipe capped and the vents on the oil filler pipe capped off and the engine did not like this at all. If caused excessive pressure build up and oil was leaking from around the supercharger due to excessive pressure.

I think I should stop fiddling with the car now as I may end up breaking something.

Car is running perfectly now.

 

Can you share some details regarding this construction?

Something you made yourself, or did you buy it finished? If so, where did you get your parts?

My screen is torn you see

 

My air straightener was purchased from Treadstone here is the link: HoneyComb MAF Mass Air Meter Airflow Straightener- TREADSTONE PERFORMANCE

The honeycomb air straightener slides in and I had mine secured with superglue or you can use a sealant.

 

Google finds that MazdaManiac says OEM intake diameter is 3.375". When I click on link, the same text does not appear.

Did you use the 3.5" option?

 

the 3.5" version of the treadstone part actually has a 3.38189" ID making it Very close to the stock piping ID. Epoxy some honey comb pre and post MAF and it would be a good option.

 

if you are using a honeycomb like the treadstone part, having one piece before the maf should be sufficient enough due to its thickness. Two would be overkill.

 

Paimon... you know me better then that by now. Everything i do is overkill.

 

lololol

side note: for model wind tunnel simulation here, we use a ratio of 6:1 (diameter : length) on a 1/8" cell tubular straightener with no measurable turbulence. The larger your cells, the smaller your ratio needs to be (i.e the longer the straightener needs to be).

side note 2: dont worry about having to 'crush' in the edges to make it fit, it will not affect flow, only the thickness of the boundary layer (very very very slight drag)

 

I had the omp vented to atmosphere after removing the vacuum line. Now, I have attached a line to the intake as per OEM configuration.

I think this will be my last change for now.

 

Car is running well with all the changes.

I have noticed that boost transition is a lot smoother when I add a couple of drop of oil in the bypass valve. The bypass valve is spring loaded piston like mechanical device. I also notice that the boost gauge shows a slightly higher and sustained boost level when lubricated.

I am guessing that the spring may need to be lighter so it can maintain sustained boost. at the moment I get a rush of power which appears to decrease as boost drops off until I change gear.

I know I did not want to fiddle anymore however, I am itching to give this a try.

 

Gave the bypass valve a good clean. I found a spring that was wider so it should distribute the force more evenly across the diaphragm. The new spring has slightly less tension and same height when fully compressed.

After a couple of WOT runs I found that the car stays in boost longer and but dyno seems to indicate more power. I think the bypass valve was not allowing the car to go into full boost.

The earlier dyno runs also showed a drop off in torque after reaching its peak.

 

Photo of disassembled bypass valve. The new spring is on the far right. The spring sits on the round brass plate which is screwed onto the piston.

 

Little things like that are what make the difference between a great setup and an ok setup .....

 

hmmm where did you get the spring?

 

It was an absolute fluke. I looked at my box set of spanners and saw a spring on the swivel joint. So, I took the spring out and measured it against the spring in the bypass valve and it had the same compressed height albeit with a slightly less tension. It was also wider, which is what it wanted to apply even force across the diaphragm.

So, this saved me from having to look for the spring from hardware stores as my original plan was to take the spring out and go shopping.

 

Decided to move the pod filter into the engine bay so I can run a larger filter for better air flow. I have kept the piping in place to direct fresh air to the filter.

For now I have enclosed the factory air box to shield from radiant heat and it seems to work as the filter and surrounding pipe is cold even after driving through traffic with occasional WOT runs. The down side of this change is that the pipe work is a lot shorter and the distance between filter and MAF is probably too close. However, I have the air straightener in place so it should help with the readings.

Unfortunately, I am now getting hesitation around 4000 to 5000rpm. The last time I had this issue it was resolved with a water decarb so I will give this a go tomorrow. There has been a notable drop in power since this issue started. I have sprayed some brake cleaner into the two LIM nozzles and will leave this to soak overnight.