I was told that the throttle body off a 5 liter will fit my Buick 3.8 vr commodore.. Is this correct as I don't know the size off a 5L's TB. And if it is installed the same way. Thanks
The first question to ask is: Is the throttle body a restriction to airflow? Maybe try the following: With a VR you already have a MAP sensor. Measure the Voltage out of that - off the top of my head, I think it's the green wire, in the centre of the connector or pick it up at the PCM - using a DMM, with the ignition on and engine off and then again with the engine under load, as in WOT up a steep hill. There won't be much difference between the Voltage readings but then you can move on to figure out where the difference is; air cleaner box, air filter, duct or TB. To measure where in the intake system any restriction is you will need to make more measurements. You can do this by removing the MAP sensor hose from the manifold (and plugging the nipple in the manifold - hose, hose clamp and bolt) and connecting it to various points tapped into the intake - plastic garden irrigation fittings and Blu-Tack to seal are OK for this - and measure the Voltage under the same conditions as the first test. You'll probably want to have replacement parts available so you don't have to plug the holes but those parts are cheap enough used. (With the MAP sensor disconnected, at least one fault code will set and the car will run using the TPS as the load signal. It won't run as well as it does with the MAP connected but it is OK for the purpose of testing, particularly at WOT. Some engine management systems always operate using the TPS as the load signal.) If you don't like disconnecting the MAP sensor, you could source a MAP sensor used and arrange a 5V signal and earth to it for a stand alone vacuum gauge. Actually, doing that makes a very useful diagnostic tool. (It can be connected to the car electrical system or run off battery power - your choice.) There are heaps of circuits for regulated 5V around (= search). Ideally you would use vero board to mount them on but even thick cardboard - like the back of a notepad - can be made to work for something temporary. (How do I know? ).
. The only reason you would want to swap a Throttle Body is to reduce any restriction to airflow (at WOT) it causes. Restriction in the intake system will show up as a lower pressure in the inlet manifold (at Wide Open Throttle) relative to local atmospheric pressure. ^ is an inexpensive and easy way to measure the inlet manifold pressure (at WOT) and where the pressure drop is occurring. If the TB isn't causing much pressure drop, there's little point in replacing it.
Still doesn't answer the original question the OP asked though. Just miles and miles of boring as batshit text.
Haha it's alright. I've just heard people say bigger TB, bigger TB. more power and I was unsure, and I was told to put One in my car.
You could bolt 4 of the TB's on your car and it would made 3/5th of fark all difference... The amount of air getting in isn't the issue at all and allot of people think it is, in fact its a design flaw with the actual inlet manifold. So attaching a bigger TB is nothing but pointless and a waste of money. If you want more power from air intake mods, look at a larger inlet manifold with twin TB's which is more suited to your needs...
Funny....Made perfect sense to me. Basically using the MAP as an electronic vacuum gauge to test vacuum at various point in the inlet track.
it shifts the torque curve a bit and improves throttle response, cylinder airflow is much the same. This is on stock with intake/exhaust/extractors.
Speaking from personal experience. Had a 5 litre throttle body. Noticed a little sharper response nothing to write home about. Found a cheap 70 mm response was a lot better and picked up speed easier. Coupled with a Mace tune it turned a boring family car into a tyre spinning menace.
