LT1 throttle body question

[graphicjunkie]

I'm looking to purchase my needed 58mm throttle body for my LT1 engine.

Not having ever dealt with this before, I'm a little confused. I see prices anywhere from $250 to well over $500 depending on brand. Now if this was a carb, I could see where there could be differences in models. Correct me if I'm wrong, but the throttle bodies only deliver air. No mixing, no nothing...just a flippin 'door' to regulate how much air is delivered.

 

So my question for you guys with throttle body knowledge is this: Is there any advantage to buying the $500 unit over the $250?

I'm simply looking at the models that Summit is offering.

 

Or maybe there is a model most recommended.

 

This is for my 1995 LT1 if it matters.

 

Thanks.

[jbc3]

I have had a BBK for over 12-13 years and it's just fine still. Of course back then there were no options.

Holley, you're paying for the name and the $500+ unit has the nitrous jets. Hell, I'd probably try the Summit unit if it was available back then.

 

Jody

[grumpyvette]

save your money!

swapping to a larger 58mm tb on a mildly modified LT1 won,t do much but make your wallet lighter. the stock tb easily supports 550 PLUS hp

if you want to boost hp get a better cam installed, its will do alot more for the money spent in hp that results.

 

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=641&p=859#p859

Edited April 21, 2009 by grumpyvette

[deja]

I was thinking about getting one for my LT1 build but everything I have read on F-body message board confirms what grumpyvette says. Unless you do radical things (better heads, big cam) your stock throttle body will be just fine.

[graphicjunkie]

Well, I was told I had to get the 58mm, because a have a heavily ported/matched set of heads and intake manifold that require it. I'm still trying to figure out what cam I want to get. I have a set of roller lifters as well. Gotta match all that up. But you're saying that it will support over 550?!

 

I guess I need to know what will happen if I throw fire to this thing and I'm not getting enough air? IE, if I don't get the 58mm can it cause harm? I don't believe so, if anything, it would make it run rich? I don't know. This stuff is all kind of new to me.

 

I plan on getting the air foil for the TB too....or is that a waste of money as well?

 

THANKS!!

[deja]

With all that work I would get an upgraded throttle body too. All I'm changing is the a GM hot cam with 1.6 rockers.

[grumpyvette]

math doesn,t seem to be a strong point here is it!

 

look a 383 spinning 6400rpm

(WELL OVER WHAT A HOT CAM WILL PROVIDE AS A PEAK POWER RANGE)

could in theory pump 697 cubic feet of air thru its cylinder,s but the truth is that youll seldom exceed 90% volumetric efficiency even on a race engine at over 5000rpm with a sbc,ESPECIALLY WITH STOCK HEADS ANDASTOCK EXHAUST, but lets say your at 90%, thats roughtly 630 cfm the engine could be useing with a 383, given the fact your even thinking about the hot cam or any cam in the 225-235 duration range youll never come close to those figures. thatswhy the stock tb. will work just fine and why a 58mm won,t do much but reduce the crispness in the throttle responce

 

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=641&p=859#p859

Edited April 24, 2009 by grumpyvette

[graphicjunkie]

K...don't be so ...grumpy... on those of us that are still learning. C'mon. :burnout:Gotta learn somehow, somewhere.

 

I'm ASKING if it's something I really need at this point. I thought it was, so I was going that direction. But if it's not, that's something I am all ears about.

 

I'm planning on going with a big cam. But what I have to do first is find out the deck clearance on my heads with pistons and all...which I also haven't figured out what I want to do. I currently have some 11:1 compression pistons @ 20 over that I have been planning on using, but I'm not sure now. I would prefer a larger cam that has a higher RPM/later response. Less power off the line to help with launch (less being a play on words with that much power in a light car...)

I might go with 30 over, and lower compression. Either way, I am waiting to get my heads back so I have those numbers and can calculate compression.

 

As far as exhaust goes, I plan doing side pipes, and am still trying to figure out if headers or the ramshorn w/ the larger pipes would be better. So stock cam and exhaust are definitely out for me.

 

And on a side note, thank you for the input/education.

[deja]

I certainly bow to your engineering expertise, its way more than I really understand. That and what I read on the F-body sites is why I'm NOT getting a bigger throttle body.

BTW I did notce the LT4 still used the 48mm throttle body even with the better heads and intake.

 

math doesn,t seem to be a strong point here is it!

 

look a 383 spinning 6400rpm

(WELL OVER WHAT A HOT CAM WILL PROVIDE AS A PEAK POWER RANGE)

could in theory pump 697 cubic feet of air thru its cylinder,s but the truth is that youll seldom exceed 90% volumetric efficiency even on a race engine at over 5000rpm with a sbc,ESPECIALLY WITH STOCK HEADS ANDASTOCK EXHAUST, but lets say your at 90%, thats roughtly 630 cfm the engine could be useing with a 383, given the fact your even thinking about the hot cam or any cam in the 225-235 duration range youll never come close to those figures. thatswhy the stock tb. will work just fine and why a 58mm won,t do much but reduce the crispness in the throttle responce

 

http://forum.grumpysperformance.com/viewtopic.php?f=55&t=641&p=859#p859

[grumpyvette]

even the BIG BLOCK 502 cubic inch ram jet engine still uses the 48mm tb