edlebrock, summit brand, BBK, throttle bodys.... any good?
06-09-2008 | 04:45 PM
#21
TECH Senior Member
iTrader: (3)
Joined: Oct 2006
Posts: 7,564
Likes: 4
From: Decatur, TN (N-W of Athens)
"if" you feel a larger TB is required check out ASM (arizona speed marine).
the most common problem with "aftermarket" TB's is idle/surge issues. The "fix" is to drill a hole between the blades (same place as on the stock TB). BEFORE you do this you must first scan the car for IAC and TPS counts. You can use a volt meter to read TPS (.67 vdc closed and 4.5 vdc full open) but a scan tool to read IAC (idle air control) wants to be about 32 (30-35) with motor at operating temp.
Your tune is set up assumeing the IAC and TPS counts are 'right" and when they are not the IAC is going ape shiat trying to settle causeing idle up/down issues. Aftermarket TB's do not provide the air inlet hole for the IAC to read.
cracking the blades open will result in the TPS being off. Some do it this way and then "notch" the holes on the TPS to "trick" the PCM because you can then position the TPS off angle from stock.
IMHO the drill mod is the 'right" way. You do need to have the PCM adjusted for a larger TB for a A4 car. line pressure needs to be bumped up or tranny failure will occur. generally stock motors do OK with just a 52 mm without and hole drill...but a stock motor really will not benefit from a larger TB.
for 'plug & play" a bored stock unit, IMHO, works best and does not have the driveability issues with most aftermarket units.
having been down the BBK path and doing the drill mod on it i found the idle OK most of the time but the blade fit to the casting left little to be desired. It was a 'cast" body vs a "billet" one. it is the loose tolerances of the cast unit on the BBK that typically causes the "whistle" between it and the blades at idle.
the most common problem with "aftermarket" TB's is idle/surge issues. The "fix" is to drill a hole between the blades (same place as on the stock TB). BEFORE you do this you must first scan the car for IAC and TPS counts. You can use a volt meter to read TPS (.67 vdc closed and 4.5 vdc full open) but a scan tool to read IAC (idle air control) wants to be about 32 (30-35) with motor at operating temp.
Your tune is set up assumeing the IAC and TPS counts are 'right" and when they are not the IAC is going ape shiat trying to settle causeing idle up/down issues. Aftermarket TB's do not provide the air inlet hole for the IAC to read.
cracking the blades open will result in the TPS being off. Some do it this way and then "notch" the holes on the TPS to "trick" the PCM because you can then position the TPS off angle from stock.
IMHO the drill mod is the 'right" way. You do need to have the PCM adjusted for a larger TB for a A4 car. line pressure needs to be bumped up or tranny failure will occur. generally stock motors do OK with just a 52 mm without and hole drill...but a stock motor really will not benefit from a larger TB.
for 'plug & play" a bored stock unit, IMHO, works best and does not have the driveability issues with most aftermarket units.
having been down the BBK path and doing the drill mod on it i found the idle OK most of the time but the blade fit to the casting left little to be desired. It was a 'cast" body vs a "billet" one. it is the loose tolerances of the cast unit on the BBK that typically causes the "whistle" between it and the blades at idle.
Also, while driving (haven't check idle) my IAC Counts are like 52 >_> I've never really asked what the appropriate step count is while cruising (cruising being 45mph~).
You can PM me if you feel like it, but I figured I'd keep it here since it is related to TBs.
As for TS&M, they're great but a bit pricey from my recollection.
