i don't know the specifics, but you have to install a jumper to trick the ecu into adjusting the base timing.

 

traveler,

Are you refering to the UNICHIP piggyback? I'm probably going to install one on my car as soon as I pick up some headers. This unit seems to have the functionality of a complete stand alone. I've done my research but, I have yet to find a 3rd gen Protege with this piggyback. The nice thing is that you get a full refund if you aren't happy with the unit.

 

dude, i think you have to stick with driving and not mechanics. every timing light i've used tell you what your ignition timing is set at, NOT the cam timing. the cam timing is constant (on our engines) and determined by the timing belt or chain.

 

To more closely address what Jesse said, I think you're saying that this is not a conventional "piggyback" computer. The conventional type (APEX'i Super AFC, Venom 400) intercepts the sensor outputs and feeds fake information to the *input* side of the Mazda ECU, which will not work because of the closed-loop WOT mode.

I have heard of computers that intercept the ECU *output* and use the stock ECU injector outputs to time its own injector signals, allowing you to tweak the A/F ratio. Are you describing this type of computer? I have heard of these being used on other types of cars, and that they're typically a lot more difficult (and expensive) to set up than a "conventional" piggyback, which seems to agree with what you said

Just curious. Lemme know how well it works

 

From my understanding, The reason why there wasnt much of a hp gain from the run w/ no muffler. You want as little back pressure as possible, but you need a little back pressue with an NA car. Turbo cars on the other hand dont handle backpressue at all, thats where you would find the most gains out of removing the muffler, just from what I've heard.

 

backpressure=typical hot rodder tale. backpressure, like APC is the enemy.

 

Just checked today. Yes, it's the Unichip by Dastek. The owner of the shop with the dyno got hold of them this morning. The thing they need to know is what kind of crank trigger we have, and what the cam position sensor is seeing. They need to know if it's just once per revolution, or if there are multiple points on the cam it picks up. I've looked at the pulleys, and there look to be 2 points that the magnet would pick up on. As for the crank trigger, we can check output with an oscilliscope or simply take it apart and count the teeth. There should be an odd number and then a gap between them. I'll check when I take it apart again to do the exhaust cam.

Dastek says that with that info they are sure they have a unit that will work. They've done all the other Mazdas including the FS engines in 626's and probes and are sure that they can make it work on the Protege. By the way, the WOT setting is considered open loop not closed. Closed is when the engine adjusts constantly, open is when it goes to fixed values and ignores the sensors. This is what can be adjusted by the Unichip. Also, it can adjust the spark advance anywhere in the RPM range. Once I get the shop owner the info, then he'll call Dastek and get them to recommend a module.

So, the WOT settings are open loop and this can be overcome. The part throttle stuff can be adjusted with a Unichip, but the stock computer will just change settings until it sees what it wants. And yes, this setup changes the outputs to the engine but only at certain times. It can be set up to always modify the spark but it only modifies the A/F at WOT. Fortunately you can tell it what RPM you want it to take affect at so if I do this we will start to cut it in at 3500 RPM since that is where the stock ECU seems to want to pull timing out and put fuel in.

 

One thing I almost forgot to mention. There is a possibility that changing only the intake cam may be one of the causes of the too rich WOT condition. The exhaust cam should be here today or tomorrow and I'll probably install it over the weekend. Then, I'll dyno it again and see what the A/F is doing. If changing the exhaust cam bumps the A/F back at least somewhat closer to what it should be, I would recommend doing the cams only as a pair. I'll know for sure when I get it dynoed again with the exhaust cam in.

 

Traveler, once again, thanks for the great info on the Unichip and your dyno testing. I wouldn't think the FS-ZE intake cam would be the cause of the engine running rich at wide open throttle. Once the ECU goes into open loop mode and provides fuel based on a preset matrix, the additional airflow from the cam should make the mixture leaner, not richer right? The MazdaSpeed exhuast cam was developed for a special edition Sport 20 in Japan which didn't much additional HP, if I remember correctly. It also had the lighter flywheel (3 lbs), and slightly higher compression pistons (10.7:1 vs. 10.5:1).

 

The thought here is that while we might be getting more air to the engine, we aren't helping it get out. This also happens on V-8 engines that don't flow well out of the exhaust ports. With those you use a split duration cam (longer on the exhaust side) to try to overcome bad port flow. What I've done with the J-spec cam is increased the duration of the intake without any corresponding increase on the exhaust side. It acts about the same as having a poor flowing exhaust port. That's the reason I did it this way was to see what each individual cam would do and what affect it had on the overall engine performance. If it doesn't help out to put the exhaust cam in, then I'll try the Unichip. Basically I'm trying to build a database on what works and what doesn't. Both of the techs that were supervising and running the dyno said the same thing. Get the A/F up to 12.5-12.7 and advance the timing a few degrees and we'll have an immediate 15 HP.

 

hey, i had a little time so i plotted the numbers that were posted. (i averaged the values since there wasn't much deviation)

 

ah the strength of the F-series engine, pretty flat torque curve for an NA engine!

 

very strong indeed! the only thing i don't like about this engine is that the torque drops more than 15 ft-lbs between 4500 rpm and 6000 rpm. (and the redline is at 6500 rpm!) if there was any thing i could change about this engine it would be this: to make the torque stay above 100 ft-lbs. (at the wheels through-out the rev range) if this were the case, the power at the wheels would be close to 120 hp! (not the 105 as seen)

 

The Unichip looks very promising. Almost as good as a stand alone while not altering the vehicle nearly as much. Cheaper too, if Traveler is right about the $595 figure. It sounds like a must for anything other than simple bolt-ons with the Mazda ECU. Check out these sites for more info:
http://www.dastek.co.za/
http://www.racersgroup.com/theprogram_unichip.html

Interesting quote from the Dastek site:

"Torque on the wheels doesn’t mean much because a slight difference in tyre profile will show up as a major difference in torque on the wheels. (The power on the wheels will remain about the same). If we take two similar cars with only slightly different profile tyres and run them on a chassis dynamometer we should see that the power is very similar whilst the torque will be radically different. If we test these cars on the road we will find that the power will be an indication of how they perform against each other and not the torque. (Realise that torque on the flywheel is not dependent on gear ratios, tyre profiles etc and has true meaning.)"

 

Damn you Eric! I've been talking about Unichip for a long time now! What does a guy have to do to get recognized around here. LOL

just kidding