The dyno margin of error made that not the porting for there is no way that makes a intake runner handle more air nor the cylinder volume larger.

Besides the intake manifold alone has surplus air volume, cylinders hold grams of air/fuel while intake maintains many times more then that.

Consider a C6 now has a 90 mm TB and has 100 HP less then my 99 which still uses the 75 mm TB and engine never is starved for air and thats a fact.

 

You can get as technical as you want but I dyno'd before and after with no other changes and I stand by it not to mention how many poeple have has similar gains.

 

I would use a carbide cutting bit to get it down a bit then switch to sanding drums..

Just like you would a head.

DO NOT USE ANY TYPE OF STONE. you don't grind aluminum, not only does it not work well its actually dangerous.

To think a better flowing throttle body will not help and actually hurt is rediculous.

 

so basically I want to sand it until it is smooth right? How about the thing tbyrne sells? VR velocity stack? Seems good to me, $50.00 not a bad price, but is it worth it? Can I hurt anything by porting myself? I'll take some sandpaper and sand it down gladly, but worried that if I don't sand evenly i may mess something up and make airflow worse.

 

another thought is a 90mm throttle body any better than a say 70mm throttle body? What is stock size? Thanks.

 

hmmm... a lid doesn't make the intake runner handle more air nor does it increase engine size. however, there are dyno numbers that prove that they increase power.

i think that a crappy tb port job will definitely cause tuning problems and hinder performance, though. i know that there are LOTS of ls1 cars out there with a ported tb, no tuning problems and fine running cars.

 

A lid is not increasing ariflow its allowing a bit cooler airflow that reduces intake air temps which is a colder aircharge which is fine.

Mucking around with the shape of TB does not do that and its common sense that the smallest diameter of a path restricts the total path just as using a 3 inch exhaust system and then using a muffler with a 2 1/2 inch inlet.

Sure you can muck with porting but all it does is cause PCM to readjust the calibration and in most cases causes less performance.

 

I think you should learn alittle more about ls1's then check out ls1tech and learn about ported tb's. If you still want more proof I can find as many threads as you want with dyno results.

 

so what do you guys think of the vr velocity stack???

 

Chassis dyno results are useless, you can make them have any results as you want. They do not give exact results and dyno pull 3 will have better results then the 1st pull and thats without porting anything.

Learn the basics, hmm, tell me if a cylinder can only hold a maximum 1.2 grams of air/fuel then how do you pack more int that volume just because someone sands a bit of a TB ?

Porting a MAF or TB has only one effect, making a vendor richer.

 

Team: This is why I was inquiring about porting it myself. It doesn't look like I will bother if it is a huge hassle.

 

Mike contrary to what he is saying you have been to nedyno I did before and after pulls with my tb and gained 7rwhp and 11 rwtq you know they don't play with the settings to change what it should read. Take it how you want.

 

"A lid is not increasing ariflow its allowing a bit cooler airflow that reduces intake air temps which is a colder aircharge which is fine

um...dude...a lid does NOTHING of the kind!! it has nothing to do with cooler air intake temps. that would be the FRA or a SSRA/ftra or similar. the lid has less restriciton on the inside by elimintating all those useless "fins", and also has a bigger less restrictive outlet towards the maf. none of that has anything to do with intake temps

a lid is all about restriction, or eliminating it, which is the same concept behind porting the TB, making the engine work that much less to suck in air. this increases the efficency therefore increasing hp.
how much will the TB help...well that's arguable...i honestly find 7hp a bit much. like i posted earlier...maybe 2-3hp.

 

i dunno about that. an aftermarket lid has a LOT more volume under it than a stock lid as well as being a good bit smoother inside. if what you are saying is true, then why would anyone bother cleaning up and polishing cylinder heads? using your exhaust analogy, a 2 1/2" restriction in a 3" system will slow flow down at that point, to be sure. however, if you have a poorly designed 2 1/2" restriction, it may very well flow like a properly designed 2" restriction at a particlular volume that is being passed through it.

as for the pcm- if a ported tb is causing calibration changes, then obviously it is causing a change in flow. like i pointed out, i don't think that anyone here is going to argue that a bad port job won't adversely affect performance or cause tuning problems. however, properly done, smoothing of the air intake path is a good thing at higher rpms

 

alright guys, just ported throttle body, in middle of oil change now so we'll see how it goes. I also did the bump stop mod. I just took my air tool with those wire brush wheels, and grinded away on the inside. Smooth as glass. I'm impressed with how easy it was and how nice it came out. Wish me luck. I'll let you guys know how it rides.