Installed modded TB on car last night...all sensors are working and no mechanical problems with the TB itself; however, the car makes a horrendous screeching at idle and there is incredible suction at the oil filler cap hole; the classic PCV issues.

Now here'* my guess...this little hole in the back of the TB that is filled with epoxy (circled in red below) is an air inlet to the cranckase, and part of the PCV system, right?


So, what do I need to do? Drill out that passage? Get a vented/filtered oil filler cap?

I do believe that is for th pcv.
I left that hole alone on mine and didn't have any issues.
Just drill it back out.

Got in touch with the original owner. He had this TB on a turbo setup with a separate crankcase breather.

I will drill or dremel the passage back open.

Nice work, Agra. I'm still intrigued by this misalignment issue... could there be a slight difference from year to year? I haven't installed my TB yet, but Doug claimed there were no issues with fitment. I'll have to report how mine fits when I get it on the car.

It'* interesting that you chose to keep the outlet of the TB round and mate it to the oval UIM. I'll be looking to see your impressions of that setup. Perhaps there is no shape-matching that needs to be done?

Does Doug have pictures? Maybe he has the same issue, but just doesn't see it as an issue. Maybe it'* not...I don't know. I just know I'd rather not have any gasket showing...especially at the bottom, where the coolant passages are.

I don't know if that'* going to turn out to be an issue, either. I guess if I experience any weirdness, like uncontrollable knock or leanness in one cylinder, I'll know.

A little work with a drill and here we are with the breather passage:




Reinstalled on car and no more banshee screaming or oil filler suction.

Maybe I'll get some scans tonight, after it cools down from our 105 degree F heat

Here'* the latest VE graph, after beginning to tune for the modded L67 TB:



This shows significant increase in VE across the entire band from 3200 to 5600 rpm, with monstrous increase above 4000 rpm. As with prior mods, I believe this TB is complimenting / synergizing with what'* already there.
Butt dyno is just loving it. I'd call that $40 well spent.

My calculations (which I'm beginning to seriously question---I MUST get real dynos!), now put me at:
Peak crank torque: ~285-290 ft lb at ~4200-4400 rpm
Peak crank hp: ~245-250 hp at ~5200 rpm

Haven't finished the MAF, O2 or spark tunes yet, but will report when finished. With stock 2001 MAF table imported and PE turned on, IPW'* are telling me I'm over 90% of injector duty cycle, so I'll need to upgrade injectors before doing any additional mods.

VE tapers off above 4400 rpm, and really drops off above 5200 rpm. Based on some further examination of L36 heads (which I'll update in this thread
http://www.bonnevilleclub.com/forum/...ic.php?t=77163
I think the heads are my upper-rpm range limitation now.

Wow... I wouldn't have guessed an L67 TB would benefit a mostly-stock L36 so greatly! I would really like to see 1/4 mile times or a dyno graph for this car now . I'm curious how your tuning and VE graphs translate into quantifiable numbers.

I gotta say, I'm loving all the research you're doing. I foresee it benefiting many members, including myself. Keep it up!

I second that as far as hard numbers, i would love to see some. Also i have to agree about helping members, this info will indeed help myself.

and myself this is very good info for L36 owner