best headers towing a boat

[dunebashing toyota]

cool thanks guys for all the good info! im going to look into the urd fuel management system get a better fuel pump and go with the thorley headers. Whats the best performing cat back I could go with? because i dont want to go with a true dual system because that would have to be custom made at a muffler shop? and i bet would be exspensive.

 

[Stick Figure]

The real way to fix fuel issue is fuel pump, fuel injectors and URD fuel management system. If you are local to So Cal you can go to JET performance and they can custom dyno program your ECU for your mods. None of this is cheap so I hope you have deep pockets.

Problem is that only fixes his fuel issue not the timing curve problem he can't see. The MAF sensor is what the ECU bases both fuel and ignition advance off of. Making the pipe larger and lowering the signal makes the ECU inject less fuel and advances the ignition timing farther than it should be for the given amount of air.

This is the same thing that makes most of the cheap fuel controllers on the market suck. You install larger injectors and manipulate the MAF signal to "tune" the engine, but the changes to the spark timing can be enough to destroy the motor.

 

[Alabamaguy]

Don't worry about the FRP. The stock injectors aren't at the edge of their duty cycle with a stock motor so the ecm will compensate any extra fuel that you may need. I would go back to the stock MAF housing. You never want to mess with the MAF sensor or housing on a modern EFI engine if you don't absolutely have to. In the world of LSx cars (and most MPI MAss Air systems are the same) a CAI throws the tune off considerably. And without tuning software available in the 5vz world I wouldn't mess with it too much, especially something homemade. It's the same thing with headers. I've personally seen many cars lose HP from factory numbers with a set of headers before a re-tune.


Just my .02 sense but I've been in the performance world for a while.

 

[BigSkyMT]

The mass air flow sensor should be able to compensate for the larger intake? All it does is measure incoming air and alters fuel mixtures/ignition based on its readings. Did you disconnect/reconnect the battery after installing the intake? To allow it to relearn? I would think after several trips it would have relearned by now. But I have seen a few techs get burned by not disconnecting the battery or not resetting the ecu to allow it to relearn. (on other vehicles). Would drive horrible after replacing the MAF (similiar issues), and spend alot of time diagnosing other potential faults and it ended up being just needed to relearn. Just my 2c.

 

[Stick Figure]

The mass air flow sensor should be able to compensate for the larger intake? All it does is measure incoming air and alters fuel mixtures/ignition based on its readings. Did you disconnect/reconnect the battery after installing the intake? To allow it to relearn? I would think after several trips it would have relearned by now. But I have seen a few techs get burned by not disconnecting the battery or not resetting the ecu to allow it to relearn. (on other vehicles). Would drive horrible after replacing the MAF (similiar issues), and spend alot of time diagnosing other potential faults and it ended up being just needed to relearn. Just my 2c.

Yes if the MAF itself isn't altered. In his case increasing the diameter of the tube its sampling from recalibrates the MAF itself with out telling the ECU its getting a recalibrated signal.

Google MAF housing upgrades and read up. The LS400 housing in the MKIII Supra is a pretty famous upgrade as are the 2G DSM in the 1G cars, there are multiple GM and Mustang MAF swap upgrades from the past as well. All involve larger injectors usually at a close % increase equivalent to the diameter change in the MAF housing. Still doesn't fix the timing issues but usually raised the amount of head room on the top end to accommodate more boost/airflow.

 

[Alabamaguy]

The MAF is now in a larger housing so it's only measuring a part of the air moving into the motor.