Hawk 137

52 mm throttle body on a ram air inyake system but a stock intake manifold. Will I get any gains or will I get turbulence and loose power?

Hawk 137

Also it shifts differently it feels less firm. I have an automatic tranny for the 95 Firebird do I need someone to tune the pcm for when it shifts?

Hawk 137

Haha I pushed the transmission perform button and its all messed up it does not **** right at all in that

hrcslam

You need to tune the car for that throttle body, especially automatics.

FWIW, I'm pushing 400+ rwhp on the stock TB and intake untouched.

96capricemgr

iTrader: (1)

Stock intake is pretty much THE choice, people INCORRECTLY ASSume that since there are upgrades for thfor the bigger TB. gen 1 and LS motors the LT1 intake must need replacement too and it doesn't.

as said the automatic tranny needs tuning

BALLSS

OP

larger than stock TB require PCM tuning to adjust line pressure for automatic tranny.....or tranny failure can soon follow

96capricemgr

iTrader: (1)

oh, and aftermarket throttle bodies usually need some mods and adjustment to the TB itself to function and idle right.

Hawk 137

I have a tps sensor and not a TV line

hrcslam

Yes, the transmission selects gear, line pressure (and shift speed) and shift points based on RPM, speed, TPS position, and MAP pressure. You need a tune with that throttle body.

Hawk 137

I can't get a tune in till next week is it possible to use the auto stick to shift at higher RPM's so I don't cause any damage

hrcslam

No. Line pressure is determined by the TB TPS and MAP sensors. Shifting manually doesn't change line pressure.

Put the stock TB back on until you get a tune.

BALLSS

your lack of understanding about what you are doing is going to cost you $ and net nothing in performance.

larger TB's have their place on larger C.I., H/C motors with the proper "supporting" mods

while the 52 mm won't hurt performance on a basic stock motor........ as you found out your transmission was not shifting properly. Your tranny is saying stop what the F you are doing until you do what is needed to install one.....assuming you even need one

Capricemgr also brings up another good point in that many aftermarket TB's require modifications to get them to idle right. No big deal if you know wtf you are doing, have scan software to read IAC counts the adjustments can be made. A stock TB bored to 52 will be way easier to deal with but you still need PCM adjustments for auto cars

Unless you have H/C, headers, larger injectors you really don't need a larger TB. If so fine but we don't know what other mods you have

lt1-xjs

I have ran across a few articles were people have ran actual tests on switching to 52mm throttle bodies. They have all netted 6-7 hp and tq.
http://www.superchevy.com/how-to/eng...-motor-part-2/

Fast350Z

iTrader: (2)

I have a stock TB bored to 52 mm on my Z28 with auto transmission and never had any issues with it. The car was never tuned and the transmission shifts the same as before I installed it. I always heard that the 58 mm throttle would mess with shifting on auto cars if not tuned.

hrcslam

What year is your Z?

Fast350Z

iTrader: (2)

Its a 1995 camaro Z28.

hrcslam

The 52mm TB on your car will effect the automatic transmission, whether you feel it or not. There's no way it doesn't. The way the computer selects its gears, shift points, shift speed, and line pressures are directly effected by the TPS and MAP sensors, the relationship between those two are directly effected by a change in TB bore.

I've seen it too many times where TB mods are done on an automatic car and the trans fails prematurely due to clutch wear. You don't always feel it, but it's happening.

BALLSS

^^^^^ this

Hawk 137

I switched back to original tb am I good or am I f'd

96capricemgr

iTrader: (1)

The problem isn't instant.
What happens is the engine is making a little more power for a given throttle position so at each shift it slips the clutches just a little more than designed. Can contribute to a slow death of a tranny.