Will this make a big difference? I am thinking about getting it. Ebay Item

 

bump I was wondering the same thing...

 

Well, considering that the only difference between the vortec 5.7L v8 throttle body and the vortec 4.3L v6 throttle body is the diverter on the throttle blade, I would say it's a waste of $170. I would just cut down the diverter. I wouldn't suggest removing it completely, but cutting it down to match the 5.7L diverter (~3/8" tall - stock for the 4.3L is ~7/8" tall).

I have mine completely removed and I am going to be getting a replacement. When I removed my diverter, I had no change in WOT performance as seen by my scans of runs up to 70mph. Only change that I noticed was throttle tip in. The pedal is MUCH more sensitive now at low throttle positions. But I will say that everything else is stock on my vehicle so maybe if you have an aftermarket CAI and headers, you may gain more by trimming down the diverter.

And I will say that the diverter has a purpose. It is meant to even out the flow of gasses from the EGR valve to all of the cylinders. You could create a rich condition in the front cylinders while causing a lean condition in the rear cylinders. All of which would even out by the time that the exhaust gasses got to the O2 sensors. I actually am slightly seeing this in my Bravada now. I pulled the plugs about a month ago and that is what prompted me to get a replacement throttle blade.

 

would you have to bore out the intake manifold if you got that?

 

Most likely, Yes. Then you may have issues with the o-ring seal, etc. In reality, if a 350 v8 can use the same bore (75mm) with a smaller diverter, why would a 4.3L v6 need a 78mm one.

 

I learned this the hard way. I have a 27 foot Bayliner express cruiser, with a Vortec Marine 350 V8 in. I, tinkering around with ways to create more power, decided to remove the diverter. Well, it ran great for a season, I had modified the exhaust a little (can't do too much with it but I modified the exhaust bellows for a straighter run and and got a better performing set of manifolds and risers) until one afternoon, I was 20 miles off the coast of NJ, heading back for shore, moderate cruise at 3400 rpm, when...BLAM!!! The engine was hurt, I cut the throttle back and let it die. Turns out piston #8 blew, due to lean mixture in the back of the engine, and it overheated, something the engine temp gauge would never show you. These were supposedly hyperutectic pistons, which should resist heat and wear like forged, yet are much lighter in weight. I really suspect it was a regular cast piston, but anyways it sent a chunk of that piston through the bottom of the pan and blew out the side of the engine block as well, oil and water everywhere needless to say. Well, bought another longblock, and I had to order another throttle blade, and learned my lesson on tinkering with that, especially in marine applications. The marine longblock was expensive, and to tow me back to the marina cost almost $800....Ouch!!

 

hyper pistons are actually pretty sensitive to lean conditions and will burn through. in race engines with hypers its reccommended to run a few jet sizes richer as a safety...


i'm with swartlkk. its a waste of $, unless you have made signifigant mods to necessitate more airflow into your engine. your current throttle body is probably flowing all the air your engine can handle, increasing that capability isnt going to do a thing unless your engine actually needs it.

 

not worth it- i will be porting my own maf and TB- but i wont port the TB to much even when running 10+psi. theres no point. i will be getting a cfm-tech TB blade though. besides i hope to have a 6.0L LQ9 with a ford 8.8" and 4l80e in the blazer bye next summer (keeping the rearmount turbo but upgrading to a T70 w/ .81a/r.

 

This mod only makes sense if you plan on running at 4 thousand rpm or more. Sustained . and if you have a power booster of any sort (supercharger, turbo), Headers, free flow intake air system, and free flow exhaust if you dont have at least any of these items forget it! You will have to reflash your ecm , you will get codes, and yes you will have to enlarge your plenum. It will cause driveability problems such as lurching upon take off. The origanal throttle body is more than adequate. Just do as everyone is telling you remove the restrictor plate. And once you add power booster's then look at it again.