Blazer Forum - Chevy Blazer Forums - TBS Or Intake Or Both

Ah sorry, in your other post, I thought you meant throttle body, not TBS... Well, if you want a TBS, do yourself a favor and have a machine shop just cut on a chunk of aluminum exactly like the underside of the throttle body. They should be able to pull the dimensions pretty quick. Only thing you'll have to deal with is the lower support for the throttle & cruise cables that mounts to the lower intake. When I was in college, I had 100 TBS kits made up for the Intrepid 3.5L & 3.3L v6s and sold them on DodgeIntrepid.net. I had a set I had bought on my car with the fru-fru swirls inside. About all they did was create an annoying whistle sound at about 2700rpm. With my spacer, not only did the car pull better off the line, the whistle was gone. Only difference between mine and the purchased ones were that mine lacked the swirl'd bore that inpinged upon the incoming air flow.

A TBS works by effectively increasing the intake runner length. By doing so, the torque curve gets shifted lower in the RPM band. As a result, the peak torque occurs at a lower rpm. So say the peak torque is at 3000rpm, a half inch spacer may bring the peak down to 2700rpm. The rest of the torque curve will just shift causing more torque off the line, but less torque at higher rpms. So if you are racing around town all day at 4000rpm, then a TBS is not for you. But if it is just your daily driver, you could see as much as 1-2mpg increase and better throttle response.

Onto the intake. Compared to other vehicles, the air intake on the 4.3L is pretty free flowing. Another good thing about it is where it draws in its air. It pulls air from behind the headlight outside of the actual engine compartment. The problem with so many of these eBay intakes is that they throw a cone filter into the engine compartment and pull in hot air. Hot air is much more of a performance killer than the little restriction of a paper filter. Best bang for your buck would be to put in a drop-in K&N (making sure that it isn't over oiled) until you can build your own cold air box around a cone filter. It also wouldn't hurt to replace the accordian tubes with smooth walled tubes. I'm mostlikely going to be replacing my 2 accordian tubes with thin walled aluminum tubes at some point and just use the stock airbox with a K&N. Most cone filters don't really have all that much more area than the stock flat filters do anyway and many actually have less area. It is true that the cone filters provide a better air flow scenario (as far as how little the air has to turn to get where it's going), but to take full benefit of it, you really need to have a box around the cone to pull outside air in.