Hi Guys, On my 95 LT-1 A4, Iv'e been trying to finish up getting the last couple of bugs worked out on my car after the LE-2 heads and cam swap along with several other motor and drivetrain mods.......the problem Im having has been touched on by a few others on this, and other forums, but not in exact detail(that I found)........The problem: after opening the throttle blades a little the car is idleing very well at about 850 to 900 RPM's in neutral & park.......but when the car is put into gear(with my foot on the brake) ,or when slowing down from a roll, the idle drops too low....It dosn't stall , but sometimes it comes pretty close.....After reading some of the other posts on this pretty common issue with head and cam cars, im assuming that the IAC is a little too slow to react to the low vacuum conditions at times...please correct me if im wrong..... I understand some have had good luck with drilling or enlarging throttle body holes (I think in the throttle blades themselves or somewhere in the throttle body itself conected to the IAC port(Im not sure which)......"THE QUESTION":.can someone please point me in the right direction where the EXACT best place would be to put this hole, (or holes)..........thanks a lot in advance............by the way, other than this super small problem, the car is an absolute animal........much props to Lloyd Elliot for his top quality work and endless help during the process ..............Joe Buttacavoli

 

..any help or suggestions would be greatly appreciated

 

hope that helps- ive had similar problems with mine since my build so did a lot of research.. in the end i got lazy and now ive just gotten used to it. Cant expect to do these mods without sacrificing some drivabillity

good luck - let me konw how it works out for you if you try.

 

Thanks Kingman........I had also found those posts during my first long search, but I was thinking more people would chime in with what mod they did for similar idle drop problems after their larger cam installs.......It's seems some are drilling the Throttle Blades themselves, and some are drilling the hole in the center near the IAC.........I guess I'll just start with the center (existing hole) near the IAC, and mabe make it slightly bigger.........I also had an aftermarket airfoil that was almost fully covering that area, mabe that was limiting the airflow in that area......I'll try removing that first.....If I get it figured out , I'll post exactly what size holes, and where, cured it for my engine combo..........and yea I agree that after mods you get some little problems here and there with drivability, but this is way too much of an annoying problem for me to get used to, and not look for the fix........Iv'e had cars with cam's in the 270's @ 50 that diddn't have this problem, so there's a way to get it to completely go away............Joe

 

no prob - now that i think of it i got an SLP airfoil in place right now... should check to see if its blocking the passage at all. Can get embarrasing sometimes going through a parking lot and it looks like i cant drive standard.

 

We'll, I have the problem about 99% corrected, it's plenty fine to live with now, but I'll probably mess with it some more .......come to find out, my TPIS airfoil, was not allowing enough air to be taken in thru the IAC bypass hole directly behind the lower portion of where the airfoil goes....the TPIS airfoil "does" have a small opening at it's bottom to facilitate some airflow behind itself to the IAC bypass hole, but clearly not enough for my engine requirements......just removing the airfoil fixed much of the problem.......I then brought the existing hole behind it up to a 13/64th drill bit size, "from" the 1/64 size it was from the factory.....and this took care of the rest of the idle drop problems......after the hole is inlarged , the throttle blades may need slight adjustment to lower the higher idle......I then reinstalled the TPIS airfoil after I had enlarged the hole to the above size, and "still" some of the problem returned, so I have to assume that the IAC hole gets air much better, with a ram air effect on it, without the airfoil in it's way.....I have it Idleing in park at about 900 rpms with a nice healthy chop to it and instead of it dropping down way, way too low when pulled into any of the drive gears, it stays at about 800 and sounds even meaner, but perfectly steady....also no more idle drop while braking......the slight idle surge it had under light load conditions is also gone........

 

Great to hear- looks like ill be giving that a chance soon as weather permits