well, figured out what was causing me to struggle to make boost on the Chevelle. It was not the intercooler, although it's on the small side for this engine/turbo config. I was seeing 5-6 psi drop from the turbos (17 psi) to the intake (11-12 psi after the intercooler). So when Gerhard at Bell Intercoolers said my core was much too small and even guessed the pressure drop without me telling him, it all made sense.
You guys who said to drop the exhaust and see what happeens were on the right track. The car has a custom built 3" mandrel bent system to the rear of the car, with a pair of Stainless Works 3" turbo mufflers. I've noticed that the car is
very quiet, so I pulled the exhaust apart at the muffler inlet and found that instead of the straight-through style I thought they were these were the chambered muffler. So I bought a pair of Magnaflow straight through 3" mufflers, same size as the SW units I had on the car, and swapped them out yesterday. I did it for more tone, and had a local car show today to try them out.
I drove out this morning, liking the new tone (not loud, pretty mellow), and never put my foot in it. On the way home I had to pass some slow moving traffic and rolled into the throttle.................. holy crap, the car is totally pissed off now.
I immediately glanced at the boost gauge in time to see it fly past 20 psi and pulled my foot out of it. I experimented just rolling into the throttle and the boost comes up lightning-fast, way too much though for this combo.
I'll pull the extra springs out of the wastegates, and dial the boost controller back now. Evidently there must have been massive back pressure in that exhaust with those mufflers, because with that single change the car is completely different. Reminds me of the yellow car as far as power, but much smoother in it's delivery.
The only bummer was the car caught on fire about a block from my house.........
I couldn't stop on the street, ditches on both sides, nowhere to pull over, no water to put the fire out. Turns out there were two fires going on; my fuse block was on fire, put it out with a water bottle after cutting the voltage at the battery. Also, the ps pump had spit some fluid out and it hit the downpipe, so small flames there. Let me say, I should have listened to Steve Rupp when he made a post recently about fire extinguishers. The car will not be driven without one from now on.
No damage to the paint or underhood, but the fuse block will have to be replaced. No car show next weekend like I planned, but at least the car makes boost now...........
Jody