Malitude's boost issues solved
 

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. :wow: 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......... :faint: 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........... :thumbsup:

Jody

Good to hear. And I've learned to never run chambered mufflers on a turbo application. I guess you've shown why. That sucks about the fires though. Hopefully they didn't do too much damage. If you need any info on the good extinguishers, let me know. There are a couple good ways you could go. Either way, look at getting Halon.

I would have never picked chambered mufflers for anything, especially not forced induction. This was the exhaust that was on the car when I bought it.

Jody

Jody....you would have been the last guy I would have thought would drive with no extinguisher. I am glad to hear you got lucky.:yes: For the rest of you guys.....don't drive your damn car without one unless you want a total loss. Listen now of pay alot later.

Wow what a post ... Killer fixed the problem!! Then oh I had a couple of fires....:wow:

Glad you have boost and some thing still left for boost.

:cheers: :cheers: :cheers:
rick k

I guess he no longer needs to re-engineer the intercooler.

makes me wonder what the old combo would have dynoed with decent mufflers................... ;)

Jody

I carried water, does that count??????????!!!!!!! :D Yeah, actually have three regular extinguishers in my shop, but wanted something not messy like halon for the car, and hadn't picked one up. Could have been ugly for sure.

Jody

Don't mean to beat on you but you know how it is. Once people see your car and my car caught on fire maybe we can talk em into a little safety. Glad to hear you figured out your boost problem and you can enjoy it!!!! :cheers: And any extinguisher is better than nothing.