Throttle body

[Kid Racer]

Hey guys how does a throtyle body give you more hp..I now a stock one on 3rd gen camaro are 52mm and you can buy a 58 mm but I just dont under stand. Why is a 58mm better the a 52mm...

And on intake runners I am looking to get a set of slp runners.. I have been looking at some and they say that they add more hp to, how do they add hp and all..

[black95maro]

bigger tb=more air=more power

[Kid Racer]

Okay how much more power would you say, I mean is 350 bucks worth it and what about the intake runners...

[The Fixer]

Originally Posted by black95maro

bigger tb=more air=more power

Right. However, on a TPI car, a bigger TB is not gonna give you more hp, especially on a stock motor. The stock throttlebody size can support 300hp. Even the 330hp LT4 used a stock 48mm throttlebody. Once you dig into the motor and REQUIRE more airflow (better flowing heads, more agressive cam) then the bigger throttlebody is a worthwhile investment. A heads/cam car would see a nice improvement with a 52mm TB; I put one on my car and the butt-o-meter says my ZZ4-cammed 355 needed it. A 58mm is pure overkill, unless you've got forced induction or a ridiculous cam and head combo.

The SLP runners work on the same principle. Better airflow = more power. The tubes are bigger diameter than stock, and are also siamesed at the top of the runners to aid in flow.

[Kid Racer]

okay thanks guy you have helped me alot..

[Pampered-Z]

How they work, think if an engine as a big pump, it pulls in air/fuel, ignites it, then pushes out the waste. The engine having to pull in the air and push out the exhaust takes away power that would otherwise be applied to moving the car. The more air you can more easily feed the engine, or restrictions you remove (intake track or exhaust) , the more of the power made can then be applied towards the wheels. A TB or runners help get more air into the engine, likewise headers, free flow exhaust reduce the effort to push the exhaust out. Use the old example of trying to run while breathing thru a straw, you can't run very well because you can't get enough air in or out. use a bigger the straw, you can get more air in/out. Engines work the same way.

But there is also a limit, bigger is better and too big can actually be a bad thing. Part of the process is volocity on the intake, and back pressure on the exhaust. The volicity helps keep the air flowing into the engine or scavange the cyclinders on the exhaust time. So too big actually can hurt the engines ability to make power.

Unless you have the mods = Heads/Cam/headers etc. then putting on a 58mm TB is more likely to hurt your performance. The Computer meassure the air in the intake and adjust fuel timing accordingly, also the volocity of the air moving into the intake plays a part in how the engine runs. a 58Mm Tb is really for a engine making in the 400+HP range.

That being said, on a stock internal engine a 52mm will give you a bit more power, a 58mm can actually cost you power.

Just so you know what to expect, the TB and runners will only add a slight amount of power as you are still restricted by you cam and the airflow of your heads. Don't expect a big jump in power. But those mods pay off if you do internal mods later, where the stock TB and runners would then be the restriction.

Dang TPI Monte! You beat me on my responce. I guess I took to long typing!

[Kid Racer]

So I can go with the 52 mm and a set of slp intake runners and be okay...And not loose anything like hp....Because the car has headers and exhaust already on it....

[Batman]

You may lose low end torque with the SLP runners, although they are probably the best average of the "Long runners". There is always a swap and with stock internals if you go for the higher HP of longer intake runners it can push the powerband up in the RPM range. Without a cam to go with the runners the only place you will see a noticeable gain is at the track. It will most likely be a little slower to take off ont he road.

[The Fixer]

Originally Posted by Kid Racer

So I can go with the 52 mm and a set of slp intake runners and be okay...And not loose anything like hp....Because the car has headers and exhaust already on it....

If you're talking about a TPI 350 car, then yes, those parts will probably help, especially if you upgrade to a bigger cam someday. I doubt they will make any difference on a 305 car; if anything, they'll hurt performance. My buddy Jay has a mostly-stock '92 TPI 305/5-speed Z28. He put a set of SLP runners on his car, and he really didn't see any improvement at the track; in fact, I think he lost a little bottom end torque because his short times were slower after installing the runners.

Originally Posted by PamperedZ

Dang TPI Monte! You beat me on my responce. I guess I took to long typing!

Sorry, I have speedy fingers!

[Kid Racer]

Yeah my car has a 350 tpi in it....Okay so a cam. slp intake runners and a 52mm throttle body.....Right

[JL8Jeff]

You'd probably be better off with the Holley Stealth Ram intake and a 52mm TB. The TPI runners will limit flow. The stealth ram intake is similar to the LT1 intake. Do some research and shop around. There are different models of stealth ram for the various engines so make sure you find the right one. They pop up on Ebay a lot. Here's a good article for you.

TPI Holley Stealth Ram

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[edpontiac91]

I know from personal experience that the 58 mm throttle body(on a STOCK internals) will cost you about 2 tenths at the track and about 1-2 mph. I have ALL the BOLT ON goodies on my 350(SLP runners-Air Box/Edlebrock headers and intake/MSD//BORLA/Air Foil/prom chip/160 stat and more. I was running 13.9 to 14.0 @ 99 mph. After I put in the 58 mm throttle body, the car was running 14.1 to 14.2 @ 97 mph. Needless to say, in went the STOCK throttle body. You WILL need the SLP fresh air box plus a 160 degree stat and a Hypertech 160-172 degree fan switch to keep that heat sink cool.

[Kid Racer]

what is slp fresh airbox

[The Fixer]

Originally Posted by JL8Jeff

You'd probably be better off with the Holley Stealth Ram intake and a 52mm TB. The TPI runners will limit flow.

-

Jeff is right. If you want a cam/head combo that pulls to well over 6K RPMs, the Stealthram intake manifold is the way to go. You'll trade some bottom end torque, but gain big-time upper RPM horsepower over a TPI manifold. Even modded TPI systems (bigger runners, ported plenum, bigger TB, etc.) run out of air around 5500 RPMs, so using a cam that makes peak HP above that is useless. If you decide you want a really torquey motor that won't see above 5500 RPMs, then keep the TPI and modify it with the bigger runners and TB.

[sinistr]

you can also port out your stock throttle body slightly and smooth out the bar/bracket on back of the blades to increase airflow slightly ... i cant see you needing to much more throttle body

[edpontiac91]

Originally Posted by Kid Racer

what is slp fresh airbox

Instead of getting your air from your stock air cleaner assembly, this unit bolts to an area(on your pass.side)right alongside of the fender. It now draws the air from an opening that runs down to the front of your lower front air dam, so that when you are moving, it pulls in fresh OUTSIDE air, and not the HOT stuff under the hood.

[Kid Racer]

oh i see

[Fast92RS]

On Camaro's IIRC the SLP kit forces you to relocate the battery to the trunk.

[NightRydaSS]

How about for an LS1 car, i have the SLP 80mm MAF, would a bigger TB inprove power? I see a lot of 90mm ones but i kno that is prob over kill on my stock internal. suggestions?

[Mike]

Originally Posted by NightRydaSS

How about for an LS1 car, i have the SLP 80mm MAF, would a bigger TB inprove power? I see a lot of 90mm ones but i kno that is prob over kill on my stock internal. suggestions?

ported stock tb will do you good

[bubba428]

Originally Posted by NightRydaSS

How about for an LS1 car, i have the SLP 80mm MAF, would a bigger TB inprove power? I see a lot of 90mm ones but i kno that is prob over kill on my stock internal. suggestions?

I've heard people say they lost power with the 90mm.

[NightRydaSS]

Originally Posted by cbrrmike

ported stock tb will do you good

about that, how do u do that?

[Batman]

Originally Posted by NightRydaSS

How about for an LS1 car, i have the SLP 80mm MAF, would a bigger TB inprove power? I see a lot of 90mm ones but i kno that is prob over kill on my stock internal. suggestions?

A ported stocker o any of the nice 78MM T/B's is plentyfor you. A 90MM will bog your engine down so bad it will run like crap. I wouldn't recommend a 90MM on an LS1 for anything less then heads/cam set-up a forced induction car over 500 engine HP.

[Kid Racer]

Hey guys do you guys now if edelbrock makes a tb. for a tpi motor...

[Tru2Chevy]

Originally Posted by Kid Racer

Hey guys do you guys now if edelbrock makes a tb. for a tpi motor...

I don't know if they make one, but unless you have a big host of mods planned, you don't need one.

- Justin