Individual PW adjustment.

I know that my car is too rich at 11.5:1, turbine is too big, and compression is too low, but this is another reason to not tune cars at 12.0:1 AFR.

 

How did you calculate this?

 

724 is 3.37% lower than 749. 3.37% more than 11.5 is 11.88. I was seeing wideband readings of around 11.8 or so all weekend, and I've said several times before that anything leaner than 12.0:1 is detonation city in my experience.

Spooky, if there was detonation on the dyno, nobody heard it, including Oscar Jackson Sr (some of you may know the JRSC, Jackson Racing SuperCharger) who was standing next to the engine bay for several of the high-boost pulls. I'm sure the timing contributed to it, since removing timing will cure detonation in most cases , but I don't think there was any on the dyno. Once the IATs jump up, probably caused by trying to stuff 22psi from a 2871R through a 22x6 eBay core, that very slight lean condition is the last piece of the detonation puzzle. Like I said, all the other cylinders look essentially perfect, but number 3 is thoroughly trashed.

 

I'm tuning for 11.2 and keeping it that way.
When is the rebuild starting?

 

Starting? It's pretty much done. Some things changing, some things staying the same.

2002 longblock/head, 83.5mm 8.6:1 Supertechs (1862cc), M-Tuned rods. Bringing my '99 oil pump over with the BE gears, as well as my ARP head studs. Also switching to an AEM EMS for the knock sensing and individual trims, as well as VVT control and trigger wheel capability. That's all pretty much done, just waiting for the ECU, injectors, and tranny to arrive. I went through my 6-speed as well, replaced the reverse gear/synchro and the 5/R shift fork and bushing (damage from my 130mph 5-R shift at Willow a few months ago). This is all to make the final Miata Challenge event.

Once that event is done, I'm going to pull the head back off and go through it. +1mm valves (possibly inconel exhaust valves), port&polish, coat the chambers and whatever else should be coated, and do a set of springs. Cams will probably stay stock to start with, but I do want to play with some high-lift stuff so I may have the head clearanced for more lift while it's apart. I also want to do an intake manifold. I have an extra '01 lower IM in my garage which I'm going to cut the flange off of to graft it onto an Edelbrock B18 piece. I'll start with that and then in the spring Tim and I want to play with something a little crazier than that, to see if we can match/beat the Edelbrock flow up top and pick up a little mid-range too. I haven't decided where to go with the water injection, either direct port or something right after the IC to keep IAT in check.

ECU will get a quartet of EGT inputs and I'll rewire the injectors and coils to enable individual cylinder spark/fuel trims.

Once all that is done, I want to go through the fuel system and do a full E85 conversion. Cooler combustion temperatures means lower EGTs and lower CLTs, which I like quite a bit. I think I'll end up with a ~95 octane map for track days at 14psi and ~300whp, and an E85 map at 24psi or so for competition events.

After headwork, an intake manifold, and E85, 400whp shouldn't be an issue at all.

 

Emilio got to you, eh? Me too.

 

It's not something I can do all the time, since a full tank of fuel every session would get old really fast. But the benefits can't be ignored for comeptition events where I need 400whp to be in the ballpark.

 

Nice writeup, make sure you document the process for us al here

 

I don't want to belabor your thread with an argument of the benefit/detriment of E85, but I am glad that the overall sentiment on here seems to be shifting with respect to it's use. Whether people think it's good or not, there are two undeniable benefits which are well documented: it lowers EGTs by around 200*F, and it's high octane rating combats det in a performance engine. You can reach mbt before onset of det within reasonable cr and boost levels, reasonable being pretty much what any of us run on this board in our engines. The obvious down side is fuel consumption (40% more on the conservative side).

Sav, I'd be interested in how you are managing the switchover from pump gas to E85. Will you be running an FCS and scaling your two maps from inputs from the % of E85, or just pumping out and uploading your different map when you switch over? I'm thinking of trying to source a qr port to put in the engine bay to make pumping out a little easier. Still a hassle, but may be worth it.

I'm sure you've done the calculations, but for the rest who may be thinking of running E85, my (not even on the back of a napkin) calculations say that for 400 to the wheels, you will need 1200cc injectors running 70psi at the rail, and will absolutely need something like a 255lph HP Walbro or similar. I will be using 1000cc injectors with the 255lph HP for 300whp, the 190lph HP was not quite big enough even for this. The fueling requirements when running E85 can't be underestimated, and you are probably right on about using almost a full tank in a 20-30 minute session on track. You'd have to bring a drum of fuel to last the day!

Anyway, good luck with the build, and keep us posted with results.

 

The AEM EGT inputs are NOT compatible with standard thermocouples. If you want to use standard thermocouples, you will need an interface box (I explained this in a thread which minime started). You will also need to modify the AEM circuit board. BTDT.

The AEM knock sensor input is NOT compatible with the 99+ factory knock sensor. It is compatible with GM "tuned" knock sensors (e.g. Saturn), but those knock sensors are NOT tuned to a frequency which the miata motor knocks at. To connect the 99+ factory sensor to the AEM, I posted an interface circuit, which is tuned to the 13 kHz which my motor knocks at, in the ECU section. (built motors may knock at a slightly different frequency)

 

Webby, I'll be draining the tank and switching maps via PC when I switch between E85 and pump gas.

Jason, I know the AEM won't take standard K-types - from what I've read the box will take RTD-type, or so I think. I'm using a Bosch sensor which I assumed could be tuned using the 2D rpm filter map - am I barking up the wrong tree here?

 

Bosch sensor is wideband and needs to be filtered at ~13 kHz.

How much are those RTD type sensors? I heard they're fragile.
May be cheaper and better to use an adapter circuit.

 

How do I determine exactly what frequency my motor knocks at?

 

It is a calculation based on the bore of your motor. Try this link.

 

..which is not as good as recording the actual knock waveforms from a wideband sensor.

Having said that, the bandpass I built is good for 12.5~13.5kHz. I can't imagine the knock frequency being outside that.

 

A valid point good sir. Real measurement > Estimation

 

When you say wideband, are you referring to a 'non-resonant' sensor like the modern-day Bosch stuff?

 

I am no expert on E85. I've only been running E85 on 2 track days. I had it dyno tuned at Shawn Church (himself drives an E85 S2000 daily, even though he has to drive 30 miles to get it). he claim, and I concur with limited experience, it is 10% more fuel at light load, and 30% more at WOT.

I am also running richer than required. 11.9 - 12.3 AFR. E85 can tolerate up to 13.

I am running 550c injectors, and made 232whp on Kraftwerk's dyno (same dyno Savington ran). so may be 750cc injector for 300whp ? I also pulled a bunch of timing (kind of negate E85's advantage), because we were worried that it is too much on my stock motor.

 

There is an E85 station about 5 miles from where I work, but it is on an Air Force Base and thus I think I cannot use it. Dang it. The next closest one is too far to be practical.

 

The only one in long island is at JFK, and it's not for civilians either. Bogus.