Throttle body question....
02-08-2003, 04:04 AM
#1
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Throttle body question....
I did a search and could not find answer. Does anybody have or heard if a overbored throttle body will have any effect on a S/C Runner.
02-08-2003, 06:29 AM
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No one really knows. You would have to do a before and after dyno test to tell.
If the throttle body is the point of most restriction at full throttle out of the entire intake track then it may be of a benifit, if not it is a total waste.
I read an article in SCC Mag where they tried to figure all this out. They did before and after dyno tests, and before and after driver's testing keeping the dyno result from them using several different ricer cars.
All the driver's swore that there was a definate improvement and there was no question about it. Then the dyno results were made known to them. ZERO GAIN. Not one car, from stock to modified had a gain on the dyno. None of them could believe it.
In an effort to try to explain this the idea was that the larger bore and throttle plate induced a more rapid opeing of the throttle valve for the same pedal movement, AKA throttle responce. It felt more snappy, but in the end there was no real gain. The same result can be gained simply by opening the throttle faster.
They concluded that the throttle body was not the most restrictive part of the intake track. At some point there is no additional benifit of opening the throttle further since it is no longer restricting the air flow available.
Well, all that made absolute perfect sense to me, and then I started thinking...
Since I had already opened up my intake track a very long time ago with a my airbox mods, larger Supra MAF, and removing the resonator boxes, I thought that maybe I would benifit from a larger throttle body. I pulled that puppy off and sent it to RC Engineering. It is hard to remember, but I think it came back about 3mm larger. RC Engineering does really nice work.
I installed it and well, I wish I could say there was a noticable difference, but there was not. There may or may not be a slight difference, but it would take a sensitive dyno to show it.
Is it worth the cost? I can not say it is.
If you do decide to proceed with this modification, be very careful. From what I have learned there are pretty much two shops on the left coast that do this work. Many shops sell it, but in turn send it to one of these two shops to do the actual work. One shop does great work, and the other's work is not as good.
I have gotten emails from several people that had their throttle bodies screwed up having this work done. I have learned that of the two shops doing it that RC Engineering is the best and they charge accordingly. I have refered each of the people that had problems with their work to send them to RC Engineering to see if they can fix the other shops botched job. In about half the cases they could. The other half resulted in the throttle bodies being replaced.
The shops that sell the work will not tell you where they send the throttle bodies, but you can get an idea where by the price they charge. The ones that are charge a lot more are probably sending them to RC Engineering.
So, if you really want to have it done, get RC Engineering do it for you.
Gadget
www.GadgetOnline.com
If the throttle body is the point of most restriction at full throttle out of the entire intake track then it may be of a benifit, if not it is a total waste.
I read an article in SCC Mag where they tried to figure all this out. They did before and after dyno tests, and before and after driver's testing keeping the dyno result from them using several different ricer cars.
All the driver's swore that there was a definate improvement and there was no question about it. Then the dyno results were made known to them. ZERO GAIN. Not one car, from stock to modified had a gain on the dyno. None of them could believe it.
In an effort to try to explain this the idea was that the larger bore and throttle plate induced a more rapid opeing of the throttle valve for the same pedal movement, AKA throttle responce. It felt more snappy, but in the end there was no real gain. The same result can be gained simply by opening the throttle faster.
They concluded that the throttle body was not the most restrictive part of the intake track. At some point there is no additional benifit of opening the throttle further since it is no longer restricting the air flow available.
Well, all that made absolute perfect sense to me, and then I started thinking...
Since I had already opened up my intake track a very long time ago with a my airbox mods, larger Supra MAF, and removing the resonator boxes, I thought that maybe I would benifit from a larger throttle body. I pulled that puppy off and sent it to RC Engineering. It is hard to remember, but I think it came back about 3mm larger. RC Engineering does really nice work.
I installed it and well, I wish I could say there was a noticable difference, but there was not. There may or may not be a slight difference, but it would take a sensitive dyno to show it.
Is it worth the cost? I can not say it is.
If you do decide to proceed with this modification, be very careful. From what I have learned there are pretty much two shops on the left coast that do this work. Many shops sell it, but in turn send it to one of these two shops to do the actual work. One shop does great work, and the other's work is not as good.
I have gotten emails from several people that had their throttle bodies screwed up having this work done. I have learned that of the two shops doing it that RC Engineering is the best and they charge accordingly. I have refered each of the people that had problems with their work to send them to RC Engineering to see if they can fix the other shops botched job. In about half the cases they could. The other half resulted in the throttle bodies being replaced.
The shops that sell the work will not tell you where they send the throttle bodies, but you can get an idea where by the price they charge. The ones that are charge a lot more are probably sending them to RC Engineering.
So, if you really want to have it done, get RC Engineering do it for you.
Gadget
www.GadgetOnline.com
02-08-2003, 07:15 AM
#3
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Well Gadget as always you make sense. I guess I will just go with my fuel mods and save my money for something else if there is not going to be a great gain by getting an overbored throttle body. Thanks again Gadget
02-08-2003, 08:02 AM
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Re: Same for normally aspirated?
Originally posted by Cebby
Does the overbored TB offer no improvement on non-S/C'd vehicles either? I'm speaking of the 3.0 V6 specifically.
Does the overbored TB offer no improvement on non-S/C'd vehicles either? I'm speaking of the 3.0 V6 specifically.
http://media-north.com/4wd/tbintake.htm
They did my 22RE's t-body and I was pretty happy w/ the results.
02-08-2003, 08:11 AM
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Originally posted by Gadget
All the driver's swore that there was a definate improvement and there was no question about it. Then the dyno results were made known to them. ZERO GAIN. Not one car, from stock to modified had a gain on the dyno. None of them could believe it.
In an effort to try to explain this the idea was that the larger bore and throttle plate induced a more rapid opeing of the throttle valve for the same pedal movement, AKA throttle responce. It felt more snappy, but in the end there was no real gain. The same result can be gained simply by opening the throttle faster.
All the driver's swore that there was a definate improvement and there was no question about it. Then the dyno results were made known to them. ZERO GAIN. Not one car, from stock to modified had a gain on the dyno. None of them could believe it.
In an effort to try to explain this the idea was that the larger bore and throttle plate induced a more rapid opeing of the throttle valve for the same pedal movement, AKA throttle responce. It felt more snappy, but in the end there was no real gain. The same result can be gained simply by opening the throttle faster.
There are really no significant gains that you can notice on the dyno. 
sux but you do gain the response. Unless you're planning to do alot of racing i'd prob suggest trying spending the $ elsewhere and come to this mod in the end. Figure you'd be able to spend the valuable $ on mods that will help you.NOTE: also if you do plan to do this mod, make sure that you match port your intake manifold. If you don't, then just boring out your tb is useless because when it gets the manifold there will be that overbored area will not match w/ the intake manifold. (hope this makes sense)
RC engineering will probably be the best place to take your tb tho. They are very reputable and I would definitely recommend then
gl
Lance
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