In the 90's when I had one of my other GT's I remember hearing that you could increase performance by polishing (may not be best word) the inside of the factory air intake manifold. Is this something that helps or is/was even done? Or did I hear it from one of the voices in my head? If so did it help any?
It helps by smoothing the airflow. Yes, it helps and it should only be done on manifolds that carry only air. If it carries gas, it needs a little texture to keep it in suspension. Are you thinking of the Extrude Hone process? You can even have the heads Extrude Honed too.
Not sure of the process term, but I was referring to the air intake only. How much does it really help on HP on the stock manifold? And is this an easy process or would it just be better to get a CAI kit. But I have asked my dealer about adding the CAI package to my new order if they will honor the warranty. But if they will not I wanted to look at other options that leave all stock parts for now.
That's what I was talking about too. If you wanted it honed, you'd have to ship it to them and wait to get it back. It usually adds about 20-25 hp and really works but if it's a stock '87-'93 upper, the power drops off FAST around 5000-5200. What it does is force an abrasive dough through the ports and smooths every surface. Worth the money in my opinion.
I think...but have not really checked ... the stock intake is plastic so this cant be done... someone please correct if wrong...
I think you guys are taking two different things. The heads (aluminum) can be ported & polished but I think Radtexas is talking about the intake manifold (the black piece that sits on top the egine), which is made of plastic. Item on the right of this pic: http://i5.ebayimg.com/02/i/04/96/88/9e_1_b.JPG
Yes I was referring to what you have pictured here. Guess they have changed a little since I owned my 1991 5.0 GT. Thanks for clarifying.
i am sure that i read somewhere that the composite intake can NOT be ported, but i cannot remember why. i want to know when someone is going to make an aftermarket intake MANIFOLD for the 3V engines.
Polishing The intake manifold is plastic so I am not sure that you could polish the inside. You could try to polish the stock throttle body. I know on C5 vettes it was good for about 5-10 hp. All you need is some patience and very fine sand paper. A dremel tool would help.
I'm sure someone will make one sooner or later. But given how long it took for the first 4.6 intakes to hit the market. I would say it's going to be later. Possibly a lot later.
polishing a plastic intake may be somewhat pointless. some reasons they are produced in plastic aside from cost, is it flow characteristic (really smooth casting) and weight reduction for fuel consumption, of course. on top of that personally i would not want to dremel or sand that throttle body. i know on the older throttle bodies ford coated the inside with a clearcoat that helped keep deposites and sediments off of the aluminum. it may not be worth the time to sand it down for the possibility or some power. i know that on the older tb's if the finish was comprimised you it would sent the IAC motor crazy and let the idle jump. im not too sure about the new tb's but being a drive by wire integrated throttle body, things are only getting more complex. its up to you. if anyone knows anything else about this let me know.
I am hoping for someone to design an intake manifold too, I bet there is some power left to be found. For a small fortune. HA
