Jon A

I think people over estimate the effectiveness of the whole IAC circuit. Split BL's usually come from a cam that's not stock. I had serious split BL problems at idle with my cam. With the stock TB. Enlarged the hole, closed the blades, etc...helped a little but not enough to keep me from running a PE idle.

With the AS&M 58mm TB, it's exactly the same. Unmodified, it acts exactly the same as the unmodified stock one did. With a tiny hole drilled (but not sealed to the cicuit--no tube or anything) it acts exactly the same as the stock one did with an enlarged hole. By exactly the same I mean split BL-wise, IAC count-wise, etc.

From datalogging, you couldn't tell which one is on the engine. So, it isn't exactly a problem for me.

And yes, the bores are offset toward the center of the manifold in relation to stock. You have to open up the holes anyway, you just take a little more off one side than the other.

sweetride45

Jon A: Interesting information. When you bored out, did you remove the whole thing in the middle of the intake (since the AS&M has the AirFoil built onto it)?

sweetride45

Also, the gasket doesn't have anything in the middle, so I assume you cut that all away as well.

Jon A

I left the stuff in the middle of the intake. I just made the holes big enough for the blades and slapped it on. I didn't see any benefit from removing that stuff. Also, even though the IAC circuit isn't perfectly sealed, the TB still feeds the air there so I'm sure it's still somewhat functional.

arnie

Either it is sealed as per oem, or it isn't.
Either it functions as oem intended, or it doesn't.

sweetride45

Why would aftermarket not drill the "pass thru" hole in the TB like the stock TB? They made it the way they did for a reason. To me, looking at the stock one, and looking at the AS&M, it looks like the AS&M design makes more sense. I can't see them making a TB that wouldn't "work"...

Not EVERYONE has a problem w/ idle, etc. w/ this TB. I can't see what the deal would be.

arnie

Have you forgotten about my original post already? To save you some time, I've included it here. I've even hi-lited the pertinent area. How do I know this? If I had not obtained this info from the 'horse's mouth', I would not have posted it...how many times in the past? HT really does H.

I wouldn't have bothered to post this reply, by I'm trying to catch Fred. (Injuneer)

sweetride45

Why do the other TB's then that ARE for LTx have the same IAC design?

arnie

Are/were they really? Why not ask....go to the source. When were they (TBs) originally designed?

Jon A

My point was I don't think the system functions very well "as intended" either. Nearly 15% more air going to the front cylinders than the back ones at idle is far from perfection in my book.

arnie

Actually Jon, I believe they ARE functioning adequately as intended/designed. They just were not designed for the LTx vehicle that you drive. Posted this elsewhere previously, but for clarification, these TBs were designed B4 the dawning of the LT1 engine. Well, unable to vouch for the others, as I am referring specifically to the AS&M. However, are the others any different?

sweetride45

Read it from the horse's mouth, eh?

http://www.azspeed-marine.com/58mmltthbo.html

"1993-1997 LT1 / L98 / LT4 58mm, 1050 CFM throttle body. Arizona Speed & Marine has stepped up it’s 58 MM throttle valve by CNC machining from a solid block of billet aluminum. Several new features have been incorporated. These throttle bodies are direct bolt-in for the LT-1 engines."

arnie

LOL Sweet. Again.......read PLEASE....my previous posts....ESPECIALLY the post that states.....ok, again to make it easier for you.
What does this imply? I've 'conversed' (on more than one occasion) with a 'prominent' individual in the AS&M organization. Anyone can read the info from their website. Anyway, because they (AS&M) refuse to redesign their TB to REALLY accommodate the LTx series of engine, I cannot in good conscience, recommend their product. HOWEVER, I DO respect their honesty/integrity for telling me, like/the way it is. They (AS&M) apparently, do not see a anvantageous cost to gain ratio, to compel them to redesign their TBs to truely include the LTx family. What they did was conveniently add the LTx series to their application list, when GM unveiled them. It would bolt up to the intake plenum, so why not?

sweetride45

I just wanted to let you know what I read. If it says it was made for a LTx on their site, one could only believe so. I'm not taking you for an idiot, I'm just showing you my reasoning.

So, if I did the brass tube trick and sealed it directly to the "iac circuit" on the intake, that should correct any problems, right?

arnie

If you go to LJ's (Jeff's) site, he will note (and I agree with, as others here have posted) it is NOT a cureall. It WILL however, take a major step in the right direction, to rectify the problem (BLM split). It is a pain in the rectal region, but a worthwhile mod nonetheless. Take care Sweet.

BTW, LJ does not run (what I consider) mild cam timing. Check out the site. It (the site) appears to have taken a respectable amount of time to setup, and periodically update.