ken, question about big throttle bodies

[gunter96ws6]

you osaid with my mods i could not benifit from a 58mm throttle body, what kind of mods would i need to benifit from that?

[Injuneer]

Just a reference point or two.... my 381ci stroker, turning in excess of 7,000rpm and making 500HP was only using 77% of the flow capacity of the 58mm Holley throttle body. That is confirmed with engine dyno testing. GM puts the same 48mm TB as the LT1 on their RamJet 502ci/502HP crate engine.

Here a link to an interesting thread where someone dyno's a 48mm vs. a 58mm TB on a realtively stock setup, and lost HP.

48mm vs 58mm TB Dyno

[wolfdogs]

fred said it best my friend.

untill you do heads, cam..and all that stuff.... stay TB O.E.

[JL8Jeff]

Plus, with the 58mm TB you would need to enlarge the openings on the stock intake to match the 58mm, they are only 52mm.

[gunter96ws6]

could i benifit from a 52mm?

[Kevin - Blown 95 TA]

could i benifit from a 52mm?

Maybe. Maybe not. It wouldn't hurt, but consider the following:

Do you get traction with the power you already have? If not maybe you could spend the $300 on suspension or chassis upgrades. A lot of guys let the engine get ahead of the chassis setup (see my 60' time ). In my case, I need to get traction before any more go fast mods... Just a suggestion to help you have a more balanced setup.

[markd79ta]

Originally posted by Kevin - Blown 95 TA
Do you get traction with the power you already have? If not maybe you could spend the $300 on suspension or chassis upgrades. A lot of guys let the engine get ahead of the chassis setup.

I REALLY agree with Kevin. I would first set up the suspension. That is what I am doing to my car. I went with all SLP, mainly due to cost...subframes, strut tower, and the level one package, and ZR1 wheels with 315/35/17s in back, but I will purchase the BMR adjustable parts when I pull the motor in a few years along with the front saddle and control arms. However, I am setting up my car mostly for autocrossing. I will probably put a 100-150 shot nitrous system on it now (for fun), and leave it until I decide to pull the motor and build it exactly the way on want it (with a blower to counteract the altitude loss here in Denver). I also agree with Fred and Ken, but there is a benefit to using a 52mm at high altitudes on a stock motor; if you are at sea level or under 2,000 ft, save your money. I wouldn't put a 58 on it unless you plan to use a blower, and get your intake machined to mach it along with some highly worked heads.

[KnightFire]

Just to throw another view into the mix

I bought a 58mm AS&M TB before I started this 355 build-up I'm currently undergoing, but I did have a LT4 setup at the time and did not loose any HP but the gains were minimal.

NOW, I did know that I would be going bigger and badder than the LT4 had to offer so it was room for growth to me and I have to be honest, the darn thing just looks SO nice in there, LOL.

So if you plan on going with aftermarket heads and a nasty bump stick...then knock yourself out...if you don't plan on going more radical than a LT4 setup...stick with the stocker or no larger than a 52mm, the mod money could be better spent else where.


Just my .02


KnightFire