The truth about why you think the car is faster with a T/b

[Got Incon?]

This is for the people saying how much quicker the car feels with a T/B and how the throttle response seems much improved, yet they only dyno with a +2 hp difference.

I just wanted to let you know why since noone else has offered up a reason for this.


It amounts to, the bigger single blade throttle bodies let more air in faster in relation to their angle (hence pedal travel) than do the stock T/B. Hence you make more power at a certain pedal position because the T/B is more nearly fully open and free flowing than the same position with the stock T/B. I'm not saying that the aftermarket T/B don't flow more, but if you divide the airflow at any pedal position by the max airflow capable at WOT, the after market might look more like this. (THis is just an example, I haven't taken any data)


Pedal Position

0 25 50 75 100

Stock % airflow

5 22 45 75 100

Aftermarket % airflow

5 35 65 85 100


The reason for the 2 hp gain is that the two T/B in your particular combination at 100% flow are flowing about the same.

The reason for the big responsiveness increase is that at 25% throttle, the aftermarket is flowing ~12% more than the stocker. Therefore with the same pedal travel as before, you are already making 10% or so more power, and the car just "feels" stronger.

 

[03Sssnake]

You hit the nail on the head ! That is plus in my book, faster throttle response is good... Less effort, power comes on quicker...

 

[trey193]

I know theres a difference, I raced one with the Accufab setup this weekend against my stocker and he is way faster up top, and my car is no slouch!

 

[Fiveohdean]

Either that or it's the 17 RWHP I picked up on the dyno with the Accufab TB & inlet. If the search function ever works again you can look up my Accufab dyno results.

 

[Sinister04L]

It doesn't really matter to me what the hp gains are. All that matters to me is what makes it faster, and there's no doubt an aftermarket TB makes it faster!

 

[trey193]

No Doubt about that!

 

[JKD COBRA]

just like fiveohdean said, if what you say is true than how are people getting 20 or more hp at the wheels? I agree that the car will feel faster mostly because of the throttle response and having more airflow with less throttle, but. . .you can't deny the people who dyno (mostly with pullies) and show awsome gains. With pullies, the cars with an aftermarket TB usually dyno 15-20 more rwhp than the ones with the stock TB. If you look at all the people who made 500rwhp or more with a pulley/chip/exhaust, I think ALL of them have headers and a billetflow or accufab TB.

 

[OverToad]

I can dig the post. :thumbsup:

Makes me itch to get my TB on the car.

 

[JKD COBRA]

Here, I just posted these pics yesturday. The 2nd and 3rd pic show the stock and BilletFlow TB at the max throttle position. Notice how much the stock twin blades block airflow compared to the wide open BF? With this TB and some extra boost, the car will respond very well.

http://svtperformance.com/forums/showthread.php?threadid=34272

 

[slythetove]

Originally posted by OverToad
I can dig the post. :thumbsup:

Makes me itch to get my TB on the car.

Sly's Underground Garage is at your service... of course we need our other "tech" to get back from Houston with that voltmeter....

 

[OverToad]

Kev, I like the car as your avatar, but from what I've seen of your sig, I think I'd rather see a pic of your 03 :thumbsup:
Got any laying around?

 

[JKD COBRA]

Thanks OverToad Yep, I have some pics. What your email address, I will send some to you. I guess I should put a pic of my 03 in my avatar. I will have to take some pics with better quality, then I will size them down and if they look good I guess I will do it.

 

[Got Incon?]

Originally posted by KevinJKD
just like fiveohdean said, if what you say is true than how are people getting 20 or more hp at the wheels? I agree that the car will feel faster mostly because of the throttle response and having more airflow with less throttle, but. . .you can't deny the people who dyno (mostly with pullies) and show awsome gains. With pullies, the cars with an aftermarket TB usually dyno 15-20 more rwhp than the ones with the stock TB. If you look at all the people who made 500rwhp or more with a pulley/chip/exhaust, I think ALL of them have headers and a billetflow or accufab TB.

I never said they didn't flow more, I was explaining to the people who gained nothing because of their combo yet said that it felt faster.

On a near stock car, I think the TB is a waste.

 

[Got Incon?]

Originally posted by Fiveohdean
Either that or it's the 17 RWHP I picked up on the dyno with the Accufab TB & inlet. If the search function ever works again you can look up my Accufab dyno results.

Again to reiterate, I never said that you wouldn't pick up hp with a TB with the right combo.

 

[JKD COBRA]

True. Maybe not a total waste, but still true. Since its an easy mod I figured I would just put it on to help out with other mods that I will do, pulley, KB or whatever.

 

[Got Incon?]

Well if it is part of a total future plan than I don't see anything wrong with it. But as someones first mod I think theres money to be well spent elsewhere.

 

[wtw5974]

When it comes to T/Bs your should be ignoring HP gains (on stock setup) on the dyno and look at the differences in torque across the rpm range. With the increase in air flow as Got Incon? explained quite nicely, you would experience more tourq at lower rpm ranges. Compare stock dyno tests w/o the T/B and then with the new T/B and look at the difference. Don't forget, torque is what makes the car feel fast.

 

[03Sssnake]

Originally posted by slythetove
Sly's Underground Garage is at your service... of course we need our other "tech" to get back from Houston with that voltmeter....

I am a UNION wrench... I'll get around to it some time next month ... Just kidding... I pm'ed toad...anytime you cats are ready...except for friday-sunday I can do it....Gotta make one more trip to H-town this weekend...A weeknight is fine by me, if thats what you guys would like to do...

 

[larryc7777]

One thing that needs to be kept in mind is that the larger TB & plenum, coupled with a quality CAI, will reduce the intake air restriction that exists AHEAD of the SC. This, in turn, will allow an additional 1-1.5 psi of boost. Plus, unless the cause is belt slip, more boost should be retained at redline. This is most apparent to the guys running greater than stock boost. But, even the stock boost guys should be able to retain slightly more of their boost at redline.

 

[larryc7777]

I reread this post several times & I have a question about the single blade TBs. Do they have the exact same size throttle cam bracket as the stocker? If they do, then the PERCENTAGE of movement(in relation to pedal position) should be the same. However, the amount of air flow in cfm will be greater at each throttle position increment. For instance, if the stock TB was capable of 700 cfm & the BilletFlow was 1000 cfm(random figures), then you can see that the larger TB would surpass the flow capability of the stocker at about 3/4 throttle. As Got Incon? stated, this does cause more power to be available at less pedal travel.