open exhaust

i currently have full header and yosh pipe on my kz 1100 b1 (81 gpz) i was wondering if i had a custom bent straight pipe to put on from the collector back,would this run it to lean??? or is it still in the EFI parameters..or should i get an AFPR.

I think it would probably exceed the ECU's ability to compensate and it would run to lean.
In my opinion a AFPR (Adjustable Fuel Pressure Regulator) is not the answer, the real solution is an aftermarket EFI controller.

I think you can buy a aftermarket EFI controller for ~$350 now, or you can spend ~$150 for a MegaSquirt kit and assemble it yourself.

Just realized you have an 81 GPz1100, and I believe that has the Mass Airflow Sensor on it, which makes things more difficult as far as aftermarket or MegaSquirt controllers go, so I'd suggest forgetting the idea of a straight pipe (and I won't get into the noise issue).

I think this really belongs in the carb forum, so I'll go ahead and move it there.

Post edited by: steell, at: 2006/10/10 08:57

the 82 may be adjusted to accomodate.

On the 81, you should be able to do it by faking out the MAF or if it has a TPS by adjusting that. Idle is a different circuit and IIRC it's got a pretty wide range of adjustment on the 81.
Never had an 81 so haven't studied it carefully. A look at the FSM will show you what you can do.

well this will be more of a because i like the sound more than performance thing...and my yosh pipe will be on like 95% of the time, but for when i want it on (like heading out to the beach) i will slip er on...So what i may do is play with pipe diameters, just go down in size a bit from the collecter back and see what happens..(it actually ran pretty well for the minute i had the muffler right off) so if i play around with pipe sizes i may just get it right...

about the MegaSquirt:
the mass airflow sensor has to go, and you need a real throttle position sensor. The '81 FI merely has a Throttle Wide Open sensor and a Throttle Closed (idle) sensor, all other fuel calculations used the MAF. Further, the stock injectors won't flow enough, they were already maxed out (100% duty cycle) at "stock plus header" configuration.