I have a few questions for the masses out there.

1. On the J30A1 engine, I believe that the TB is 45mm. Can anyone confirm this?
2. Has anyone changed the TB on a V6? Noticible gains?
3. What is the best size for this engine??? I've heard that 48mm is ideal, but why not larger within reason, say 50mm or 55mm?
4. I've found TB's at 70 & 75mm for this engine. Thoughts?

Thanks for the help!!!

 

The throttle body is not 45mm....the F23's is 58mm


Find a spare or send yours to www.maxbore.com and with about weeks downtime you'll have your new bored out throttle body.

 

It would make sense that it would be larger. 45mm is just a number that I read somewhere. Do you know the stock bore for a J30A1? $160 for maxbore to do the work is a steal! Thanks for the heads up on them!

 

Thinking out loud.

Is the mass air flow sensor (MAF) part of the body?? If it is not would the MAF reading be incorrect due to different area? The experts will know.

Tally Ho

 

copied from Wikipedia:

Automotive mass airflow sensors A mass airflow sensor is used to determine the mass of air entering an electronically fuel-injected engine. The air mass information is necessary for the engine control unit to calculate and deliver the correct fuel mass to the engine. Air changes its density as it expands and contracts with temperature and pressure. In automotive applications, air density varies with the vehicle's operating environment, and this is an ideal application for a mass sensor. (See stoichiometric, ideal gas law, and density.) There are two common types of mass airflow sensors in usage on gasoline engines. They are the vane meter and the hot wire. Neither design employs technology that measures air mass directly. However, with an additional sensor or two, the engine's air mass flow rate can be accurately determined. Both approaches are used almost exclusively on EFI (electronic fuel injection) engines. Both sensor designs output a 0 - 5.0 volt signal that is proportional to the air mass flow rate, and both sensors have an IAT sensor (intake air temperature) incorporated into their housings. When a MAF is used in conjunction with an exhaust gas oxygen(EGO) sensor, the engine's air/fuel ratio can be controlled very accurately. The MAF sensor provides the open-loop predicted air flow information (the measured air flow) to the engine's ECU, and the EGO sensor provides closed-loop feedback in order to make minor corrections to the predicted air mass.

 

aka --- the oxygen sensor should pick up the differance. If it's too much for that to work, I could also retune the AF map, but I don't think that will be necessary just yet. I have other plans that will require remapping though.

 

has anyone done this yet? in theory it sounds like a good idea, then again so does comunism

 

I haven't seen it done on a J30A1, but bored throttle bodies are very common. I found a 70mm & a 75mm bolt-on for my car, but I can't find it right now.