Larger Throttle Body
Banned
Joined: Jan 2006
Posts: 1,139
Likes: 2
From:
RE: Larger Throttle Body
Typically, a big TB is used in combination with big head ports, and high lift cams. The bigger TB really shines when everything gets moving ( Mid to high rpm ) if you go too big, it can actually reduce intake velocity and hurt torque down low. Steve, you could probably gain a few HP, and maybe not lose any TQ, but if you gain, say, 5 HP, would it be worth 300 bucks? I got my SE TB for $189.00 because my builder bought it for an '03, and it only fits an '06. If it was full price, I probably would not have one.....
nogood o~`o
nogood o~`o
Road Master
Joined: Dec 2006
Posts: 1,058
Likes: 6
From: Omaha Nebraska
RE: Larger Throttle Body
Some things that have not been mentioned, the larger you go the more your throttle grip becomes morelike an on/off switch, more difficult and less fun to drive. Too large and you will be at full power before you are at full throttle. Often cruise control will surge because a given throttle movement over/under shootsits intended speedtarget.
One method that I have used to determine if a TB is too small, is to do a WOT pull to redline with aaccurate,dampenedvacuum guage monitoring intake vacuum. If it stays under 1 Hg, don't go larger, the bestinduction systems that I've seen are around .5 Hg. Works best if done on a dyno unless you can datalog it, for example with SERT.
Watch out if aftermarket TB suppliers merchandise how much extra HP it will provide. Often they take the highest HP engine they can get their hands on, put a stock, then thier TB and advertise that number. Not really representative of what most engines are on the street.
One method that I have used to determine if a TB is too small, is to do a WOT pull to redline with aaccurate,dampenedvacuum guage monitoring intake vacuum. If it stays under 1 Hg, don't go larger, the bestinduction systems that I've seen are around .5 Hg. Works best if done on a dyno unless you can datalog it, for example with SERT.
Watch out if aftermarket TB suppliers merchandise how much extra HP it will provide. Often they take the highest HP engine they can get their hands on, put a stock, then thier TB and advertise that number. Not really representative of what most engines are on the street.
Grand HDF Member
Joined: Feb 2005
Posts: 4,307
Likes: 9,428
From: Twin Cities Minnesota
RE: Larger Throttle Body
ORIGINAL: maineultraclassic
LOL..............you guys and your 3.37 gearing.
How about nitrous oxide...........will that accelerate like 3.37 gearing?
Steve
LOL..............you guys and your 3.37 gearing.
How about nitrous oxide...........will that accelerate like 3.37 gearing?
Steve
Ahhh Nitrous.....let's say a nice 30 h.p. kit from Edelbrock....I think my bike NEEDS it.
[sm=nxsmile.gif][sm=thanx.gif]
Grand HDF Member
Joined: Feb 2005
Posts: 4,307
Likes: 9,428
From: Twin Cities Minnesota
RE: Larger Throttle Body
ORIGINAL: geargrinder
Some things that have not been mentioned, the larger you go the more your throttle grip becomes morelike an on/off switch, more difficult and less fun to drive. Too large and you will be at full power before you are at full throttle. Often cruise control will surge because a given throttle movement over/under shootsits intended speedtarget.
One method that I have used to determine if a TB is too small, is to do a WOT pull to redline with aaccurate,dampenedvacuum guage monitoring intake vacuum. If it stays under 1 Hg, don't go larger, the bestinduction systems that I've seen are around .5 Hg. Works best if done on a dyno unless you can datalog it, for example with SERT.
Watch out if aftermarket TB suppliers merchandise how much extra HP it will provide. Often they take the highest HP engine they can get their hands on, put a stock, then thier TB and advertise that number. Not really representative of what most engines are on the street.
Some things that have not been mentioned, the larger you go the more your throttle grip becomes morelike an on/off switch, more difficult and less fun to drive. Too large and you will be at full power before you are at full throttle. Often cruise control will surge because a given throttle movement over/under shootsits intended speedtarget.
One method that I have used to determine if a TB is too small, is to do a WOT pull to redline with aaccurate,dampenedvacuum guage monitoring intake vacuum. If it stays under 1 Hg, don't go larger, the bestinduction systems that I've seen are around .5 Hg. Works best if done on a dyno unless you can datalog it, for example with SERT.
Watch out if aftermarket TB suppliers merchandise how much extra HP it will provide. Often they take the highest HP engine they can get their hands on, put a stock, then thier TB and advertise that number. Not really representative of what most engines are on the street.
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