can you post some details on how to do this? It's new to me. Maybe a link or something?

About the throttle hanging open at high rpm, mine probably does that too. When I shift from drive to od, then the rpm hangs there until it engages od even though my foot is off the gas.

 

So you're definitely dealing with a closing issue. I responded to the earlier post while signed on using L98's account.

I know Insanity's car used the mono blade without issues and Phil Tobin also used it. Don't know of any issues in either case, but both were NA apps.

I'd be looking over the shaft real closely. With the unsupported width, I don't think it'd take too much to bend it from a pressure surge when the throttle is snapped shut under boost. Hell, the heavier spring might even need to be enough to "straighten" the shaft and blade and get the amount of bypassed air down. Tony's thoughts on the BOV's are sounding right on.

The 90 mm and larger throttlebody's need to be setup with a cam for the throttle actuation. Making the opening progressive adds greatly to around town driveability. GM's gone to the bigger throttlebodies because of the flexability of drive by wire.

The throttle follower stuff I was talking about is a stategy that opens the IAC valve as the throttle is opened. As the throttle is closed the IAC follows behind to help keep the motor from stalling. The different computers out there use different strategies in how they go about this so there's not one general site to point you to.

 

Well I have exhausted all discussions with ASM (even talked to them again today). I had reached the point where I told them I was bolting the twin 58 back on. They concurred that there are some FI/high vacuum applications that just will not work with the MB (it is like a big wing/airfoil in the air stream).

The only thing that has kept me working at this, is there is one person (and only one that I have found to date; Tony) that is using the MB successfully in a FI application. Persistance has paid off (at least partially). I found a piece of 1/4" vacuum line that is "T"ed into the PB line that goes forward to the emissions canister. I had replaced this line when I changed the manifold and installed new vacuum line from O'Reilly. This vacuum line is very smooth and hard. It not only slipped easily on (and off) the T, but also slipped easily off the metal line near the front of the engine compartment. It even had clamps (factory plastic ones) that did not hold it tight. I could slip the hose off the metal line with the clamp installed snug.

I installed new "soft" 1/4" vacuum line on this location. Well, lo and behold, the throttle does not seem to be sticking. It was too dark to do any full boost runs, but I did take it up to 10 psi and this thing is just nasty fast. Maybe the very small vacuum leaks just wreak havok on the MB applications. We will see full boost tomorrow!

I still have not tuned the package with the new intake. AS&M has my powder coated TB, but I am running the painted unit (the colors are near exact).



Thanks to all of you who have provided assistance.
Aaron

 

You make a good point.. I do run braided steel lines for all of my crucial hoses. Maybe you had a bad connection, a hariline crack, or perhaps a collapse..?

 

The key to all of my difficult problems is to step away for some "soak" time. A few weeks ago, I started adding a 31.5' x 16' covered back patio onto the house, with absolutely no work on the vette. After two weeks of no work and just pondering my options, I decided to check/fix some concerns.

Eventually, all of these things work out. Tonight is cruise night.

Thanks for the help,
Aaron

 

hmm... I'll have to check out mine. I actually am having similar problems, but I don't have the monoblade (I thought I did), but rather a ASM manufacture 5/95 stock style throttle body. I drove the car last night and it was still doing it. I'll check my vaccuum lines too.

 

The saga continues as the MB continued to stick.

I swapped back to the dual 58MM billet, and the sticking is totally gone, but so is so much low end torque. I am going to the dyno soon, and plan to take the MB with me (nicely wrapped to protect the finish) and see if the shop has any thoughts.

Damn, the low-end torque is significantly down w/out the MB.
Aaron

 

Yep, mine stuck again the other day. Obviously a design flaw.....I thought I had it figured out, but I don't. I think I will try some kind of helper return spring that doesn't provide and resistance until I open the throttle at least half way.

 

Mine has the big helper spring on the MB and for that matter now the 58MM. I would just really like to be able to run the MB, as it seemed to make a "noticeable" difference in SOTP torque. It feels like I am "ckoking" the car just cruising.

One thing I will say is that the 4BBL design that bolts directly to the intake flows similar numbers and has none of these BS characteristics.
Aaron

 

I do not know why the Arizona Speed and Marine MB design has all of this trouble. There are many other Mono blade throttle bodies out there that seem to work fine, of course they are not a bolt-on item for our cars.

 

I'll be interested to see if you are actually losing bottom end torque with the twin 58 vs. the monoblade or whether it's just a matter of needing more throttle movement with the 58.

On another note. In the latest Hot Rod there's a pretty through write up on one of the Nelson Racing Engines twin turbocharged 427's. It has a custom Hogan sheetmetal intake with a Mustang twin 62 mm throttlebody. With some work you might be able to rework your hat to work with it.

Just throwing some throughts out there.

 

Well my tuner did not seem concerned with the issues of the MB and said he could tune "around it". Well after nearly 2.5 hours, the MB still sticks. But what was interesting is that at 6200RPM, the throttle only hangs about 30-40% open and the RPM pretty much stays at the WOT level. He was having one of his guys push the throttle back shut after each run.

On one dyno run, the throttle hung at 6300 and then the inlet tube blew off. Immediate throttle closure! So it is definitely related to the boost. Without boost, the throttle snaps right shut.

His advice was to get my money back from AS&M. He thinks the liability risk is too great.

Thoughts?
Aaron

 

My thoughts would be right with the tuner's. Try to get your money back. The results from blowing the hose off would be enough to convince me.

 

[QUOTE=
His advice was to get my money back from AS&M. He thinks the liability risk is too great.

Thoughts?
[/QUOTE]

Honestly I think your tuner is right..... Mine seems to hang open mostly in first and second gear. The first time it hangs open in fourth or fifth under high boost... it's gone... I'll then have to figure something else out. I'm not taking "The Trip" because of a bad design...