throttle body upgrade - wow!
Thread Starter
Launching!
Joined: Sep 2005
Posts: 270
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throttle body upgrade - wow! Wasn't expecting that from the many debates about the issue...but damn does adding that 58mm make a difference. The car definantly throws you back harder... the performance is definantly noticeable... I dont' know how much, but the car feels much more livelier.
Throttle response will be improved even if power is not. This is because say 20% throttle is now allowing a whole lot more air in. Your car may not be any faster at the track or make any more power on the dyno. Then again how much time do we spend on the track or dyno, if a mod genuinely feels good and helps you enjoy the car more then GREAT.
Thread Starter
Launching!
Joined: Sep 2005
Posts: 270
Likes: 0
I have a few goodies 
But probably not enough for the 58 to make a difference under internet claims. Yes I ported the intake as well... but the improvement from the 58mm feels like more than just a throttle response...actually that part feels about the same, but power wise, It feels like someone turned on a light switch or something. I definantly reccomend trying this mod. I haven't been WOT on the street yet.. because the car pulls pretty hard and that's just asking for a ticket. But after the TB install the car is definantly hauling it a little harder now. The engine feels like it has more power all together. Hasn't felt this good since the switch from ST's to the LT's. It's like a stronger engine now... I just hope I don't suck any CRX's or Miatas up into my intake with this thing.
I will say that I installed the 58 without porting the intake at first...and I didn't notice not one thing different...but after I opened the intake up and made the proper adjustments... I now see I got my moneys worth. I should have saved this one for the dyno... but I'll never know if it added anything... because I added a bunch of stuff onto the car and haven't been to the track in 2 years almost. Plenty of street battles though
I just don't understand why swapping TB's and adding pullies onto the LT1 get such bad raps... because after doing both of those did I notice quit a difference in performance, as where I've done other HP gainers and didn't notice a thing.
looks cool.
But probably not enough for the 58 to make a difference under internet claims. Yes I ported the intake as well... but the improvement from the 58mm feels like more than just a throttle response...actually that part feels about the same, but power wise, It feels like someone turned on a light switch or something. I definantly reccomend trying this mod. I haven't been WOT on the street yet.. because the car pulls pretty hard and that's just asking for a ticket. But after the TB install the car is definantly hauling it a little harder now. The engine feels like it has more power all together. Hasn't felt this good since the switch from ST's to the LT's. It's like a stronger engine now... I just hope I don't suck any CRX's or Miatas up into my intake with this thing.
I will say that I installed the 58 without porting the intake at first...and I didn't notice not one thing different...but after I opened the intake up and made the proper adjustments... I now see I got my moneys worth. I should have saved this one for the dyno... but I'll never know if it added anything... because I added a bunch of stuff onto the car and haven't been to the track in 2 years almost. Plenty of street battles though
I just don't understand why swapping TB's and adding pullies onto the LT1 get such bad raps... because after doing both of those did I notice quit a difference in performance, as where I've done other HP gainers and didn't notice a thing. looks cool. Trending Topics
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Originally Posted by buffman
Personally from what I've read I believe the stock throttle body becomes a restriction over 4800rpm.
Matt
Matt
Where did you get that information? I shift my car at over 7000 rpm on the 2-3.
Daren
Originally Posted by GIZMO
Where did you get that information? I shift my car at over 7000 rpm on the 2-3.
Daren
Daren
I put a 58mm TB on mine this year after the engine build, and it also made a huge difference on mine. Some say the 58 is overkill, but the way I feel, is all power is in an engine is the ability to move and burn more air/fuel, so the more air you allow in, the more fuel you can feed it. Just like exhaust, the more air you can get out, the more you can feed in.
Ive been hearing there really is no need for a new TB unless you have a **** load of goodies. Ur not going to need one if you have a C/B, but im sure for some cars a TB works well and on other setups its a maybe.
Originally Posted by brandboZ28
Youre making enough power to be shifting above 7k rpm and youre using a stock tb?
We have no choice but to run the factory pieces. My first LT1 went 11.3's with a cam, valve springs, open headers, and DFI. The LT1 is actually a lot better than most people think. With the factory cam I was running 7.9's in the 1/8th!
Daren
Want to see if it is a restriction check WOT vacuum, oldschool carbed wisdom was more than 1.5" at WOT meant a street car could use a bigger carb for race they used .5". This of course only indicates an intake restriction, it is going be be up to you to evaluate the rest of the intake and decide if it is the TB that is the restricion.
Originally Posted by GIZMO
All Stock Eliminator LT1's have to run the factory throttle body. Some guys are running low tens with them! Woodro ran a 9.88 at Rockingham with one last year in Top Stock.
We have no choice but to run the factory pieces. My first LT1 went 11.3's with a cam, valve springs, open headers, and DFI. The LT1 is actually a lot better than most people think. With the factory cam I was running 7.9's in the 1/8th!
Daren
We have no choice but to run the factory pieces. My first LT1 went 11.3's with a cam, valve springs, open headers, and DFI. The LT1 is actually a lot better than most people think. With the factory cam I was running 7.9's in the 1/8th!
Daren
Originally Posted by 96capricemgr
Want to see if it is a restriction check WOT vacuum, oldschool carbed wisdom was more than 1.5" at WOT meant a street car could use a bigger carb for race they used .5". This of course only indicates an intake restriction, it is going be be up to you to evaluate the rest of the intake and decide if it is the TB that is the restricion.
yeah dwayne hit the nail on the head. Checking to see how much vacuum you have @ WOT would give a good indication that there is an intake restriction. I think the general rule of anything over 2" represnts a good restriction on the intake tract. While it might not be your TB, it's likely it could. I'm not saying you're going to get huge gains from swapping TBs but if you're seeing a restriction you will.
I do believe the article was written by David Vizard. I forget in which book though
Last edited by buffman; Oct 16, 2005 at 05:58 PM.
As Chris96WS6 said on LS1LT1.com, Changed my mind on the matter,:
(Disregard first to Paragraphs, Applied to a different question on CAIs)
Good points Bawls. Remember the stock engine can only suck in so much air. You could create an intake that flows 200% more air but it doesn't mean all that air is going to make it into the engine.
Same thing with air filters. It only has to flow so much.
The main thing you're doing with the CAI is eliminating restrictions. Ideally at WOT you want the pressure inside the intake manifold to be = to atmospheric pressure. There's going to be some pressure drop through the throttle body, etc., but you want to minimize it.
That's why I'm an advocate of larger throttle bodies even on lightly modded cars. Some folks say because the math says the stocker flows enough to support 450hp that its all you need.
Well, yes, under ideal conditions it flows enough to feed 450hp, but its unquestionable IMO it will take less effort to suck 500cfm through a 58mm tb than through a 48mm tb and there will be less pressure drop in the process. The 58 is going to therefore allow a bit more air into intake plenum, and then when the intake valve opens there's going to be a little more pressure forcing air into the cylinder.
You can measure this yourself by doing data logging at WOT 48mm vs. 58mm and looking at the kPa differences in manifold vacuum. 100kPa is atmospheric. I was seeing 93-95kPA at WOT with a 52mm and when I went to the 58mm I get 98-100 consistently.
(Disregard first to Paragraphs, Applied to a different question on CAIs)
Good points Bawls. Remember the stock engine can only suck in so much air. You could create an intake that flows 200% more air but it doesn't mean all that air is going to make it into the engine.
Same thing with air filters. It only has to flow so much.
The main thing you're doing with the CAI is eliminating restrictions. Ideally at WOT you want the pressure inside the intake manifold to be = to atmospheric pressure. There's going to be some pressure drop through the throttle body, etc., but you want to minimize it.
That's why I'm an advocate of larger throttle bodies even on lightly modded cars. Some folks say because the math says the stocker flows enough to support 450hp that its all you need.
Well, yes, under ideal conditions it flows enough to feed 450hp, but its unquestionable IMO it will take less effort to suck 500cfm through a 58mm tb than through a 48mm tb and there will be less pressure drop in the process. The 58 is going to therefore allow a bit more air into intake plenum, and then when the intake valve opens there's going to be a little more pressure forcing air into the cylinder.
You can measure this yourself by doing data logging at WOT 48mm vs. 58mm and looking at the kPa differences in manifold vacuum. 100kPa is atmospheric. I was seeing 93-95kPA at WOT with a 52mm and when I went to the 58mm I get 98-100 consistently.
<---- LT1 with 58mm 