If i were to run a holley 52mm throttle body would i see gains? All my mods are in my sig below. What i'm concerned about is losing my bottom end (considering that's the edge LT1s have). I know buy running to big (diameter wise) of an exhaust system at times can take away the bottom end of the car.

So i'm worried by running too big of a throttle body might do something similar to over sized exhaust. Bare in mind i'm not to knowledgeable on throttle bodies. That's why i rather ask before going out and buying one.

Any advice is greatly appreciated.

 

Yes, in the form of better throttle response. And if you throw on some headers, that'll help more too since motors need to breathe, not only IN, but OUT. So the 52mm helps in, while the headers help with out.

I remember putting my 58mm on my TPI car and I noticed a ton more throttle response and all I had done was ported the upper plenum. Alls I had for exhaust work was a Flowmaster (might've been a dump at the time) and catless.

Since you're M6, you don't have to worry about a tune either. Once you get the headers though, I'd get a re-tune. Even with the 52mm you could change the VE table a bit.

 

You can get one but stay with a ported stocker. The aftermarket ones I have seen always idle funny and require some tweaking to get it right. Also you probably won't notice any power since the stock 48mm is fine for a bolt on car. I got a 52mm from ebay but I just did it after the cam since I really had nothing else to buy.

 

I have pacesetter LTs and a tune from madz28.com already. Ok so then this would be a good step forward for me thanks.




When you say stocker, do you mean buying a GM 52 or 58mm? Instead of a holley etc...?

 

No, he means a stock TB that has been bored out to 52mm from 48mm. I think the farthest a stock TB can be ported is 54. Our intakes are only 52mm stock anyways though.

And yes, I think it'll help your car breathe better.

What's that "slp flow booster"?

 

So should i talk to Brett Bauer? I heard he does ported throttle bodies right?





that's just an air foil that goes into the throttle body. I bought SLPs version.
http://www.slponline.com/view_product.asp?P=22100

 

Ah lol

I don't know how good Brett is. The ones on eBay people seem to be having good luck with and they only run like $100-$140. Some come with Airfoils already as well. Alternatively you can just send yours out to have it done. You might even have a local shop that can do it. Like me, I have TPiS just a few miles away

 

oh ok man, well thanks for the advice then, i appreciate it. I'll probably check to see if someone is local first.

 

Think i am going to go with a ported stocker, might as well have all the bolt ons anyways. For the price of a ported stocker it is not a bad deal.

 

Have any of you guys who are saying that they are seeing an improvement with a 52mm/58mm throttle body actually seen a gain on a dyno that also showed up on a time slip? The dyno session would have to include optimum tuning for both throttle bodies to be valid.

I know of at least one SS/IA LT1 Firebird that has run as fast as 9.713 with the stock throttle body (N/A).

I have a friend with an LT1 A/FI Stocker that has been 10.147 with the stock throttle body (N/A, stock lift cam!!).

I have had great results too.

Daren

 

No, I've never been to a dyno, but it was a clear as day throttle response impovement. There was also a bit of an accel improvement too, but that may just have been due to the already cranked up fuel pressure and the fact I ported the upper plenum too. But to be honest it wasn't a "Oh I think I feel something!" gain because you just installed a new part and are excited to see what it did.

 

A larger TB is not going to gain you any power on the dyno unless its already a restriction (if you have 500+ rwhp). People sometimes think it will because there can be a sotp difference that feels like a power gain, but in reality all that the larger TB is doing is putting you in the powerband quicker (since it lets in more air at a given throttle position compared to stock).

 

My 58mm TB only put 9rwhp to the wheels more then the airfoiled stocker on my H/C setup. A stock cubed smallblock just doesnt need that much more air then the 48mm can flow unless you are spinning 6500+ rpm. Of course the dyno was on different days, so it may not be entirely accurate. Not the best hp/$$$ ratio, but even so the tip-in from the bigger blades makes it a lot more responsive and fun to drive too. There was no gain at all until ~4.2k rpm. The runs looked almost exactly the same until around there. I'm sure a 52mm would have shown the same exact improvement over the 58mm, but I plan on going 383 next season and then the 58mm will pay off more.

Even though the examples you posted are true, I do not think those cars mentioned are really a great representative of real world use, since with the low lift/huge duration cams the engines use do not neccesarily need a big TB to breath in more air per intake stroke since they get their air by keeping the intake valve open for much longer then a street driven engine would. Of course its much more complicated then this, but since engines intake air in pulses and not streams, it is basically it is a longer(higher duration) but shallower(lower lift) breath instead of a shorter(less duration) but deep(high lift) breath to get the air it needs. My cam is relatively high lift for its modest 230's duration, so maybe that is why I see a benefit when full second+ faster cars with less lift do not?

Personally, even on a bolt on engine I would get one just because I like the snappy response off the line from a big TB. Of course it will not be used to its full potential cfm wise on a lower RPM/CI engine, but it will not hurt anything(assuming its tuned, i/e funky auto tranny problems due to TPS/road speed variations aside).

Like many other things it comes down to preference

It is flywheel horsepower, not rear wheel, that will determine if you need a bigger TB. My stalled auto dyno's much less then it would if it was a 6speed. It ET's better though, which is where it matters.

 

yeah I forgot the number specifically, basically just sayin you don't really need it until you get into the bigger mods like h/c.

 

Not one scientific response?

 

lol, it's been shown on a dyno that the stock TB is not a restriction until much higher hp than stock (400-500 etc).

 

I think he's pulling out the "Rule of the Internet" card. "Pics, or you're lying". Or in this case, a link with said dyno sheet/results. I'm not sure if ws6.com/org/net (whatever) has a TB dyno.

 

To make me a believer it would have to be back to back runs with as much detail as possible (coolant temp, A/F ratio, etc.). And no cooling fan running in front of the car.

 

I thought the big fan infront was to simulate driving conditions...

 

I live in Colorado, so I cant wait to get mine and actualy let my car breathe somewhat.