LS-2 Throttle body spacer
Thread Starter
Instructor
Joined: Nov 2008
Posts: 114
Likes: 0
LS-2 Throttle body spacer
I saw an ad in a car magazine displaying performance parts. One in particular was a throttle body spacer claiming to add 2-3 hp. As I recall it wasn't too expensive. I thought it was cheap H.P. Do these work and upon what principle?
Thanks,
MR.G.
P.S. Happy New Year Everyone!!
Thanks,
MR.G.
P.S. Happy New Year Everyone!!
Burning Brakes
Joined: Jan 2006
Posts: 1,226
Likes: 45
From: Castleton VA
Cruise-In VIII Veteran
First, 2-3 HP is well within the error band of most any dyno when you're up in the 300+HP range, so it doesn't take much for a snake oil salesman to pick the "best" of several dyno runs to support an advertising claim.
Second, the original idea of throttle spacers was to effectively increase the length of (relatively short) runners from a carb to a cylinder, and to possibly reduce heat transfer from the intake manifold to the carb (hard to believe this does anything useful on a fully warmed-up carb'd engine). In the LSx application, the throttle body is miles away from the cylinders -- I can't see how the additional few mm of length added by the spacer could have _any_ measurable effect on HP. As as to heat, the throttle body is already mounted way out front on a low heat-transfer plastic manifold, so that's a non-issue in this application.
Finally, if your SOTP meter is sensitive enough to detect a <1% change in HP, your tail feathers are *far* more highly calibrated than mine.
$0.02 deposited, pot stirred
HTH,
Mark
Second, the original idea of throttle spacers was to effectively increase the length of (relatively short) runners from a carb to a cylinder, and to possibly reduce heat transfer from the intake manifold to the carb (hard to believe this does anything useful on a fully warmed-up carb'd engine). In the LSx application, the throttle body is miles away from the cylinders -- I can't see how the additional few mm of length added by the spacer could have _any_ measurable effect on HP. As as to heat, the throttle body is already mounted way out front on a low heat-transfer plastic manifold, so that's a non-issue in this application.
Finally, if your SOTP meter is sensitive enough to detect a <1% change in HP, your tail feathers are *far* more highly calibrated than mine.
$0.02 deposited, pot stirred
HTH,
Mark
Le Mans Master
Joined: Dec 2005
Posts: 6,993
Likes: 1
From: Vail, Arizona
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
UD pulley 9rwhp
Ported TB 3-4
porting an intake manifold: 10-15
Aluminum flywheel: 9-12hp
exhaust cuttouts (5-6HP...stock car)
electric water pump: 6rwhp
roller rockers:10-12HP
In the end people just raised the BS flag when Tony Mamo dyno'ed 490rwhp with AFR 205 heads and a 224 cam. Other guys skipping the not-worth-it mods got 460rwhp many times over. now you know why.
The down side to increasing plenum volume is a loss of throttle response.
a search produced many papers related to TQ and the like such as this one:
http://www.sae.org/technical/papers/2008-01-3007
Drifting
Joined: Mar 2007
Posts: 1,499
Likes: 5
From: Meadville Pennsylvania
The spacer increases plenum volume which does make some minor HP increases but every HP counts. Increasing plenum volume is one thing porting does on an intake manifold (small increase) and does work. The not-worth-it guys dont subscribe to a HP here and aHP there and thus dont get the total gains that one can get from all the few HP gains.
UD pulley 9rwhp
Ported TB 3-4
porting an intake manifold: 10-15
Aluminum flywheel: 9-12hp
exhaust cuttouts (5-6HP...stock car)
electric water pump: 6rwhp
roller rockers:10-12HP
In the end people just raised the BS flag when Tony Mamo dyno'ed 490rwhp with AFR 205 heads and a 224 cam. Other guys skipping the not-worth-it mods got 460rwhp many times over. now you know why.
The down side to increasing plenum volume is a loss of throttle response.
a search produced many papers related to TQ and the like such as this one:
http://www.sae.org/technical/papers/2008-01-3007
UD pulley 9rwhp
Ported TB 3-4
porting an intake manifold: 10-15
Aluminum flywheel: 9-12hp
exhaust cuttouts (5-6HP...stock car)
electric water pump: 6rwhp
roller rockers:10-12HP
In the end people just raised the BS flag when Tony Mamo dyno'ed 490rwhp with AFR 205 heads and a 224 cam. Other guys skipping the not-worth-it mods got 460rwhp many times over. now you know why.
The down side to increasing plenum volume is a loss of throttle response.
a search produced many papers related to TQ and the like such as this one:
http://www.sae.org/technical/papers/2008-01-3007
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Verdad Gallardo
Safety Car
Joined: Oct 2007
Posts: 4,269
Likes: 4
From: Mililani HI
Spin you are the best especially in explaining things. You really are what makes this board the best.
Happy New Years everyone.
On the post about the TB spacer warping, where did you get that information from? I have been running mine for about a year and have had no problems. I would say those that have had any warpage is from overtighting the TB bolts and not tighting the bolts evenly.
To my knowledge the only warpage was on the old Vararam CAIs which they corrected.
Happy New Years everyone.
On the post about the TB spacer warping, where did you get that information from? I have been running mine for about a year and have had no problems. I would say those that have had any warpage is from overtighting the TB bolts and not tighting the bolts evenly.
To my knowledge the only warpage was on the old Vararam CAIs which they corrected.
Melting Slicks
Joined: Jul 2007
Posts: 2,052
Likes: 14
The spacer increases plenum volume which does make some minor HP increases but every HP counts. Increasing plenum volume is one thing porting does on an intake manifold (small increase) and does work. The not-worth-it guys dont subscribe to a HP here and aHP there and thus dont get the total gains that one can get from all the few HP gains.
UD pulley 9rwhp
Ported TB 3-4
porting an intake manifold: 10-15
Aluminum flywheel: 9-12hp
exhaust cuttouts (5-6HP...stock car)
electric water pump: 6rwhp
roller rockers:10-12HP
In the end people just raised the BS flag when Tony Mamo dyno'ed 490rwhp with AFR 205 heads and a 224 cam. Other guys skipping the not-worth-it mods got 460rwhp many times over. now you know why.
The down side to increasing plenum volume is a loss of throttle response.
a search produced many papers related to TQ and the like such as this one:
http://www.sae.org/technical/papers/2008-01-3007
UD pulley 9rwhp
Ported TB 3-4
porting an intake manifold: 10-15
Aluminum flywheel: 9-12hp
exhaust cuttouts (5-6HP...stock car)
electric water pump: 6rwhp
roller rockers:10-12HP
In the end people just raised the BS flag when Tony Mamo dyno'ed 490rwhp with AFR 205 heads and a 224 cam. Other guys skipping the not-worth-it mods got 460rwhp many times over. now you know why.
The down side to increasing plenum volume is a loss of throttle response.
a search produced many papers related to TQ and the like such as this one:
http://www.sae.org/technical/papers/2008-01-3007
Thread Starter
Instructor
Joined: Nov 2008
Posts: 114
Likes: 0
T.B. Spacer
Thanks to Spin and others for such a good explanations. I do have a PPTB but I don't want to sacrafice any bottom end. Two questions have been spawned as a result. First, on the Throttle Body there is a honey comb bisquit on it similiar to those on the front of some MAS air flow meters. I PP the throttle body should that honeycomb bisquit have been removed? It seems restrictive. Second, what are exhaust cut-outs? I have an 05 Automatic 2:73 gears. Where or how can I acquire one for her?
Thanks,
MR.G.
Thanks,
MR.G.