juddz

Hey, guys -
I have been considering going to a larger TB lately. On E-Bay, I've seen a number of bored out TBs, 60mm I think. There is also a unit from Cork Sport, but I do not recall the diameter. Anyhow, I have some questions for you:

1) Are there any larger diameter Mazda MAF that will work on our cars (correct connectors, etc)? What does the Mazdaspeed, or JDM FS (the 170hp one) use? How about the MAF from 626 2.0L, Mazda V6, etc? I imagine there has to be some commonality in the design.

2) Has anyone tried out a larger TB, with no other modifications? Was there any difference, or still too much restriction to be noticeable? (I doubt that there will be any gain without taking out every restriction from MAF to increasing the plenum diameter, but I want to hear your experiences if you believe otherwise).

3) Has anyone done a larger TB, and gone all out - larger MAF, extrude honed (or alternative) intake plenum, etc?

There has to be somebody out there who has done this mod... I just want to know if there is a cost effective way to go about it.

juddz

... I take it nobody has done this?!

gcs118

As far as I know, there are no other MAFs that are plug and play, and it's generally been considered that a larger throttle body is useless. I don't remember the exact discussion, but I'm sure a search will reveal why (it has been discussed more than once).

juddz

Thanks for the input. I've actually come to the same conclusion, thanks to sources outside of this forum. From what I have seen, there is NO improvement in simply switching to a larger TB without addressing every restriction in the system. That becomes especially tough, given the curved geometry of our intake manifolds. While it is possible to hone it out (extrude hone), it's gonna be bucks, and there are likely cheaper ways to get hp from the car before going that route.

Still, it doesn't stop makes of larger diam. TBs from claiming hp increases, that they can't (or are not willing to) back up with real data.

JHew84

are you saying generally considered for the 2.0? or generally as in all cars?? i know lots of people who have bored TB on their 2.5's and defintly noticed an increase in power and speed... i just got done installing the jspec IM and bored TB on my 2.5 and there is a LOT more pull in the top end, and when i say a lot it is REALLY noticble, and it holds the power really well all the way up to redline, granted the manifold is going to help as well, but i'm pretty convinced that the TB is performing like it is supposed to...

gcs118

When I said generally I was referring to the 2.0 FS-DE, yes. The Jspec intake manifolds are less restrictive as well, but the TB alone on a stock FS-DE is not uesful.

JHew84

alright cool, i really dont know a terrible amount about the FS at this point, but soon enough i'll know just as much about it as i do about the KL ...

DonSVO

throw your car on a dyno and see what it makes.

butt-o-meters dont go far for a paying customer.

you could get the same or better top end pick up by going with catless 2.5"/bigger exhaust, or just bolting a K&N directly to the MAF.