Ok so im in the process of fabbing up my turbo plumbing. The combo info in on my build thread but heres a quick snapshot....... gen 3 coyote twin turbo with ford controls pack.

Ive read multiple threads but have not heard a solid answer to a couple questions.

1st. since i will not have a full exhaust (just down pipes after the turbos) can i get away with only using the upstream sensors? if so should i place them inbetween the header and the turbo or after the turbo in the down pipe? what setup is most tunable?

2nd. MAF sensor. can i utilize the stock sensor? If not, which one do i need? How far from the throttle body is best place to get an optimal reading?

thanks
steve

 

My 2nd gen control pack only uses the upstream sensors... did yours come with 2 pairs? Either way yes, the downstream can be disabled in tune, they primarily emissions monitoring.

You can use the stock MAF, although you will probably need a larger housing. It can be something as simple as a 4 or 5" tube with a maf adapter welded to it. Then you scale it in the tune.

 

perfect. Thanks

 

Only use the two o2 sensors between the engine and turbo(s). Use a blow through MAF.

 

upstreams in downpipe . Don’t know if the o2s can handle the heat preturbo for long

 

Mine do…

 

May not be the best practice. The pressure and the heat isn’t the best for o2s . Look at all the oem turbo cars o2 sensors are mounted in the downpipe near the turbo .

 

Wideband O2 is pressure and heat sensitive. It should be mounted in a location approx 3-4 feet from the turbine where EGT is reduced to perhaps 800*F or so. High temp will skew the O2 of some sensors to reading rich which of course may lead to engine failure. Ive personally seen it happen on the dynojet comparing dynojet wideband tailpipe sniffer to the in car wideband. Not sure what temp it gets bad but best practice to keep it cool.

MAF I do not recommend blow-through for a variety of reasons. I recommend a MAP sensor instead. MAF is a fickle bitch. I've tuned hundreds of maf turbo cars and I rarely see them setup properly before I got there. In turbo applications typically a maf sensor will be placed in front of the compressor wheel with as much straight plumbing before and after as possible. It will also need a recirculated bypass valve between the maf and compressor inlet for proper control of compressor surge without having to fudge the fuel map trying to keep from washing down the cylinder walls with fuel when the bypass opens.

 

Thanks for the reply. Havent really considered swapping over to MAP. Is it just as straight forward as installing a MAP sensor and then retuning?

 

The ecu needs to support a map sensor. The fuel map has to be compatible with map sensor. You must use the exact correct map sensor calibrated to match the ECU expectations. Each map has its own voltage profile and offset.

MAP is more difficult to tune in general. The air temp variation creates density variability in the tuning depending where the air temp sensor(s) are located and how they respond. Also the engine heating itself is part of the adjusting values, not just air temp. Therefore the tuning is particular to conditions- tune for the most common conditions and tune for wandering conditions. It depends on the ECU and map sensor how much extra work is involved. Some computers lack finite tuning features which make MAP sensor tuning more general. The sensor itself just like the MAF needs to be properly used (grounded, placement, temperature, &c), connected to a good spot in the manifold, connected with a dedicated source line, no leaking or bad wiring that gets hot or interference from EMI etc...

Your question could be a general one or a very specific one. If the ECU takes a 0-5v signal then technically you can fudge any map sensor in there just by empirical testing- computers don't care what they 'think' all that matters is the values on that a/f gauge. For example if the map says 2psi but the real pressure is 15psi , the computer 'thinking' is irrelevant all that matters is the fuel map tuned properly for the condition. But that is 'wrong' and there may be some linearity issues or situational problems which arise unexpectedly, you need experience to know what you can away with. If you are new best to keep the computer in the loop of what is going on and not fudge anything.

 

On a coyote? No, its not straight forward. Not if you are using the Coyote PCM. You would have no way to define it in the strategy, and no company that I am aware of makes a controller that can handle all of the coyote features (dual injection, VCT, IMRC, you know... the stuff that makes a coyote make power) and use a MAP.

There is no reason to anyway, it would be a step backward. You can make incredible power with OEM level driveability, the factory computer on these is powerful, the sensors work, and tuning them is not that hard. You can get maf tubes up to 120MM and make a larger one if you could find the need.