DOH! MATH ERROR!



So it comes to 5 watts total at 100% duty cycle. Sorry about theat...

At 60% you're within spec (and it actually takes ~ 1ms for an injector

to pull max current)



That being said, you _might_ get away without resistors on the secondaries,

but it's risky.

 

83,



Mike's fuel pressure was rock solid. I watched a fuel pressure gauge during each run because this was something I was concerned about. If the pump was going beyond its volume capacity his fuel pressure would roll off at high rpm as the volume requirement increased (or not increase with each lb of boost)



The supra pump is rated at 225+ L/hr at 70psi at 13.5v.

At 85% duty cycle with a total fuel pressure of 70psi (15psi boost+40+15 line restriction) that is enough fuel for more than 480rwhp with headroom. If anybody is unsure of this, use Maxcooper's fuel system calculator. I did this and looked at the pump dyno sheets before deciding on the supra pump. It's one of the best pumps you can get for this car. It significantly outflows most of the walbro pumps at equal fuel pressure. Bottom line is Mike has the capcity for 480rwhp.



Given that he is running into problems at 350rwhp@13psi when, according to the test data by RC engineering his pump has enough capacity for 490rwhp at more than 15lbs of boost AND

his AFRs are extremely rich AND

his fuel pressure is holding at the set valve, AND

there are several people producing a lot more hp using the same fuel system without any problems, I would be extremely surprised if his problem was fuel related.



The injector resistors could be an issue, but again, there are many people using these injectors with resistors (myself included). Mike has gone through two sets of injectors with two different kind of resistors and it has had no effect on his problem. What are the odds of what is described to be an intermintent problem at best occuring every single time the car is boosted to 13.5psi on the dyno with two different sets of injectors?



Step back and look at all the INPUTS and OUTPUTS

INPUT:

timing: the map is conservative, I've checked and rechecked for anything funky such as negative split.

Fuel: fuel pressure has been confirmed, the injectors have been flow tested, the harness is new

Boost: 3 seperate boost gauges confirm the MAP sensor is accurate.



OUTPUT:

afrs: 10.2-10.8. The car was actually stumbling at times because it was so rich. We know the plugs for each rotor look the same and are both WET.

egts: ???

Timing: verified all the way to redline-the motor is getting the timing the ECU is set at



Conclusions/items that I for good or bad have ruled out:

Fuel: The car is setup to run rich and the outputs indicate that it is in fact running rich.

Timing: The timing appears to be accurate



What's left

-extreme oil temp: doubtful given that the problem seems to correspond to BOOST and the dyno runs are short. Also, according to Mazdatrix high oil temps cause chatter marks on the housings, which Mike does not have.

-lack of oil metering: Maybe the metering pump is worn and cannot fight against the positive combustion chamber pressure at 13.5psi to meter oil in. However, I've spoken to several drag guys that don't meter oil in or run premix. Apparently, it wears down the housings but doesn't have much of an impact on the seals.

-bad seals: doubtful because he's used both 2 and 3 piece mazda seals.

-clearancing: I don't know much about this so I can't say

-exhaust porting: too wide?-again not my area of expertise

-bent E-shaft? a track guy I spoke to suggested this

 

I think the problem has something to do with the ported motor because the problem did not start until he got the motor ported. He lost a few motors under the supervision of KD before that, but they weren't losing compression on the dyno, they were detonating and at higher boost. The last stock motor he put in got off the dyno without a problem and then blew a rear seal on the street a few weeks later at around 16lbs of boost. As Ito mentioned, this was probably due to the fact that KD wired up the crank angle sensors wrong. Remember, Mike was making 400rwhp with the stock motors (about 50 more than he is making now) and didn't have any fuel related problems. Ito obviously knows how to build a motor and has a good track record, so I tend to think the cause is a defective part rather than worksmanship.

 

Air/water/fuel temp sensors and wires okay? Just a thought.

I know you covered "what happens without metering oil", but I'm wondering if

being that overrich is washing oil out of the motor and causing problems? (like

the crankcase pressure)

 

Ito mentioned 0.002" - that's perfectly fine.



Resistors on fuel injectors shouldn't affect anything.

If anything, reaction time (or fuel injector dwell time) induced by the resistors should not affect fuel injector capability with much significance. We've messed around with fuel injector crossover phase-in, and the engine can absorb a slight lean condition (easily seen on any O2 sensor - narrow or wide) without much fuss. If you do not see a lean drop on the wide-band, I doubt anything weird is happening.



Now, this leads up to the "1600's"...

I got a heads up from Paul Ko @ K2RD that some of these 1600's are blueprinting at very widely ranging flow rates. I've heard anything from 1100 to 1800! The dual EGT set-up will confirm this right away. The "cheap" way to confirm this is to send them out to get flow-benched.





-Ted

 

Interesting, but do you really think this could happen on both sets of 1600s?

 

Also, why didn't the non ported motors fail the same way with the same injectors producing more HP?

 

Where is fuel pressure being measured? You might want to try checking it

just before the regulator, in case there is an obstruction in the line. (I'm assuming

it was checked sort of upstream, given the 15 psi system loss noted).

 

Fuel pressure is being measured on the regulator. Also if there is an obstruction Wouldnt the Wideband show the lean Air/fuel ratios? Also the car NEVER detonates.

 

We only run this rich now due to the Cars problems. We originally ran in the low to mid 11-1 range for air fuels with same issue. Also car has a brand new factory harness before this last motor was dynoed. Wires are all new.