Will larger throttle body/injectors help?
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From: Prague. the Czech Republic
Will larger throttle body/injectors help?
I am riding '08 SuperGlide Custom 103ci, KB forged domed pistons, Wood TW6-6 cams, stock heads,SE Heavy Breather intake and Bassani RoadRage 2-1 exhausts (and PCIII). Dyno chart shows resulting 95HP and 157Nm of torque (=116lb-ft) - see attached pic.
I am interested in further increase of torque, especially in lower RPM section (2000 - 3500revs). I was thinking of using larger injectors, larger throttle body and possibly some headwork. But results seen on different pages seem not to show enough increase of torque to justify for the effort.
Could you share your opinion on what would be the best way to further increase torque in specified range, please?
I am interested in further increase of torque, especially in lower RPM section (2000 - 3500revs). I was thinking of using larger injectors, larger throttle body and possibly some headwork. But results seen on different pages seem not to show enough increase of torque to justify for the effort.
Could you share your opinion on what would be the best way to further increase torque in specified range, please?
Last edited by MonteW; Dec 31, 2010 at 10:21 AM.
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From: la
Cost wise the TB isn't worth the small gain for a mild build. A 30T pulley would give you more bang for the buck. How much compression do you have?
Last edited by paul s; Dec 31, 2010 at 09:05 AM.
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From: Union Bridge, MD
you are running stock heads with this setup?
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From: Northwest
larger throttle body does not = more torque. For more torque, you actually want to have a higher velocity column of air coming into the head. If you increase your diameter, you slow the velocity.
Clean up the heads.. remove restrictions in flow ( but don't increase the diameter or volume of the intake area very much). Install a thinner ( .030 Cometic ) head gasket or consider shaving enough off the head to bring your CR up to about 10:1. ( have the heads cc'd to know how much to shave ) the increased CR will really help out that cam.
After that "I" would consider the SE-255 cams, ( but lookout for the fall-off after ~4200 or the 30T front belt pulley (which might be the better solution for you, if you want to retain some upper end.
Clean up the heads.. remove restrictions in flow ( but don't increase the diameter or volume of the intake area very much). Install a thinner ( .030 Cometic ) head gasket or consider shaving enough off the head to bring your CR up to about 10:1. ( have the heads cc'd to know how much to shave ) the increased CR will really help out that cam.
After that "I" would consider the SE-255 cams, ( but lookout for the fall-off after ~4200 or the 30T front belt pulley (which might be the better solution for you, if you want to retain some upper end.
Tourer
Joined: Dec 2010
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From: Frisco TX
That is a good running 103, the only way to get more low end then you have would probably be to go with a bigger engine, 110, 113, 120. On a couple of my 103 builds in the quest for more power, larger throttle bodys cams etc just lowered the low end torque. Injectors just need to be sized for the needs so they are not more then 80% duty cycle. Unless yours are sized wrong there is no power to be had there. Most builders think that the stock injectors are good for 100HP.
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Thread Starter
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Intermediate
Joined: Jan 2009
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From: Prague. the Czech Republic
That is a good running 103, the only way to get more low end then you have would probably be to go with a bigger engine, 110, 113, 120. On a couple of my 103 builds in the quest for more power, larger throttle bodys cams etc just lowered the low end torque. Injectors just need to be sized for the needs so they are not more then 80% duty cycle. Unless yours are sized wrong there is no power to be had there. Most builders think that the stock injectors are good for 100HP.