iWon

iTrader: (13)

So I've got a 58mm BBK on my car currently, but I'm interested in getting a Holley tb because they look so much nicer and would go with the rest of the engine. I found a great deal on a 52mm one.

So is there really much of a power gain between the 52mm and 58mm on a H/C car? Should I wait for a 58mm?

iWon

iTrader: (13)

Added my build to my sig...

RamAir95TA

iTrader: (2)

Slim to none. If you have money to burn go for it. Alot of the time aftermarket 58mm throttle bodies have IAC, TPS range and idle control issues., but I didn't have any of those issues.

Having said that, I went with a Holley 58mm on my 383 with minor issues, easily fixed. I ran a Holley 52mm for 6 years prior though.

iWon

iTrader: (13)

Yeah my car is still idling very high, almost 1000 rpm and I haven't been able to figure it out.

97Z28SS

iTrader: (5)

Hey RamAir what minor issues did you have with your Holley 58mm tb, cause I have one for my new combo and I'd like to know what needs to be fixed, thanks.

RamAir95TA

iTrader: (2)

At WOT, the throttle blades would go past perpendicular, setting a TPS voltage high code, which throws the transmission into a type of "limp" mode where it won't shift. I just had him program out the code and all is well.

BOLO

iTrader: (40)

LT1 and bolt ons=NONE

LT1 w/ heads and cam= YES and of course w/ the intake opening opened up to match the 58mm TB

Just my personal opinion.

hitmanws6

iTrader: (20)

I made sure to get my AS&M for this build, never had any issues with it

WS Sick

I have had the AS&M for about 10 years now with no issues.

Z28Camaro30Ann

iTrader: (15)

I have a Professional Products 58mm with no issues

Spiers

iTrader: (7)

If your search, there is a thread where a guy did a dyno comparison between the two. He had a mild H/C setup and put down high 300's. Peak numbers were slightly more with the 58mm but the graph showed gains of up to 20ft/lb under the curve.

iWon

iTrader: (13)

Guess I'll stick with the 58mm then, power is more important than looks for me

nitrous2fast

iTrader: (2)

It depends on what power level you are at. If your build isn't past 500 then I wouldn't worry about it.

CamaroRacing12

iTrader: (5)

imho it dosent matter the power level, more flow both intake wise and exhaust wise is always better.

but thats just my personal opinion

WS Sick

Since the thing doesnt meter the fuel its just an air door...bigger door cannotbe bad.

wrd1972

iTrader: (12)

I ran some in depth tests (MAF air flow) between the 52 and 58 on mine: see sig.

The 58mm provided 2 KPA less at WOT compared to the 52mm which will net maybe 4-6 HP gain. That was about it. No big numbers with the bigger TB.

CamaroRacing12

iTrader: (5)

attention to detail. that 4-6hp could mean the difference between winning a race and losing a race.

wrd1972

iTrader: (12)

Fair enough but for the average street car that never goes to the track, hardly worth the $300 or so investment IMO.

iWon

iTrader: (13)

Wait you're saying he gained up to 20ft/lb tq with the 58mm over the 52mm? Huh?

gregrob

iTrader: (8)

Yes. This has been dyno tested... there ARE gains to be had.