Larger throttle bodys? worth it?

[Bennetts22@aol.com]

I have a S52 obd1 that i have pretty much every bolt on already. is a larger throttle body/ silicone intake hose worth it? whats a good one? several company's sell them from vac 399.00 to treehouse 700.00. has anyone tried any of these and was there any gains?

TIA Brandon

[hoveringuy]

It will make a very small difference.

On the M54 I went from the M50 TB to a larger M54 sized one, flow area was around 15% greater but I saw 0 gains on the dyno with some small decrease in perceived driveability at lower rpms.

S52 has a better head so I think you would see more than zero but i don't think it would be much more.

[328ijunkie]

S52 head>M54? ORLY?

[nando]

there is a relatively simple way to measure if you need a larger TB or not. You need a MAP sensor/vac gauge hooked into the intake manifold. Read ambient atmospheric pressure (depending on where you live, it will be 101-80kpa). read pressure at WOT. if WOT pressure is significantly lower than ambient, your throttle is causing a pressure drop. if they are the same, then upgrading the throttle will do nothing.

[hoveringuy]

S52 head>M54? ORLY?

Yep, the exhaust ports on the M54 are restrictive. S52 definately flows better (although the M54 dual VANOS is better)


Brady went from a 67.5mm TB to 72.1mm on a cammed motor with headers over at e46fanatics. His results were mostly inconclusive and at best he gained 3hp.

http://forum.e46fanatics.com/showthread.php?t=736943&page=4

there is a relatively simple way to measure if you need a larger TB or not. You need a MAP sensor/vac gauge hooked into the intake manifold. Read ambient atmospheric pressure (depending on where you live, it will be 101-80kpa). read pressure at WOT. if WOT pressure is significantly lower than ambient, your throttle is causing a pressure drop. if they are the same, then upgrading the throttle will do nothing.

Concur. I used the standard GM MAP sensor that I got for like $5. It ouputs a 0-5V signal that integrates easily with my datalogger.

[e30rapidic]

wait a tick...aren't the heads the same casting number???

[hoveringuy]

wait a tick...aren't the heads the same casting number???

M52 and S52 are, but M54 is way, way different.

[e30rapidic]

M52 and S52 are, but M54 is way, way different.

too much calculus studying. the M5FOUR part didn't register.