2000 Buick Sleeper build - 2nd engine trashed!

[Blue85]

I went to an exhaust shop and they assured me there are no leaks. I took the guy for a drive and he agrees there is a noise, but even under load and with rags in the tailpipe, we couldn't find any leaks. So I picked up a different flex joint and have to decide whether to MIG it in myself or take the vendors advice and have them TIG it. Apparently there have been several cases of only the outer ring getting burned in, with the braid and inner flex not connected, so it comes apart.

I also replaced this 18" bullet resonator with a 24" monster:

The car seems quieter, but I will have to drive it for a bit to know if it will need a different muffler. I will probably end up replacing the tailpipe, but I'm not sure if I want to buy a bunch of mandrel bends to make my own, or just have a muffler shop do it in an hour. I also found a shop online that can do custom pieces with multiple mandrel bends in them. I may hit them up for a quote.

EDIT: the giant resonator really tones the car down. It sounds deeper and meaner, but quieter. There is still a little drone with converter locked at 1500 RPM, but I can barely hear the engine on the freeway.

 

[Blue85]

I really dug into a big project today. I decided to swap the flex pipe and clean up the exhaust installation. I had to pull the header out from the bottom by removing the sway bar and the crossover pipe. Fortunately after a lot of work, the cat did come free from the header outlet - otherwise I would have been making the first cut from underneath the car. I think the piece after the cat is part of the stock exhaust. You can see how it necks down just before that pointless flange. Also notice the partially welded clamp. Those pieces have the little slots cut in them and they weren't engaged far enough to cover the slots, which must be why they welded them.

That piece necks down to about 2.25" at the outlet.

Getting welded clamps off and cleaning stuff up enough that it can be reused is not easy. I wanted to save the cat even though it's not stainless, so it will be clamped in with these same band clamps again, but done a little differently.

So here's the $800 headers I need to cut up.

The new flex is about 1/2" longer than this one, so I can just cut the weld off the outlet. The inlet is more of a challenge. Here's what the SLP flex looks like:

To weld all 3 layers of the new flex, I stuck a short piece of 3" stainless tube in the end and made a first pass at low current to tie the inner interlock layer to the outside of the tube. You can see that the mesh layer tends to get melted in without even trying, so no need to focus on it.

The second pass was with more current, grabbing the outer ring, the first bead and the tube together. I had a lot of trouble with the welder today. The roll of stainless kept jamming like it had been wound up wrong.

The header collector outlet was actually necked down a little under 3" since their flex had a ring-type part on both the inside and the outside. The ZZP flex is just a little bigger in diameter, so after cutting off the whole upper weld I gained probably 1/8" from the stock SLP design. The short piece of tube was tucked into the collector and a bead welded around. Then I burned both of those welds together like stainless wire is cheap. Here's the finished header:

To reuse the 3" band clamps, I had to take the hardware out of the 2.25" band clamps I removed from the crossover pipe. Right now I'm thinking to weld that piece with the 2nd O2 bung to the resonator, since that resonator will be in there for good. That piece will clamp to the cat outlet. Then I'll weld the hanger hooks to the resonator inlet. I'm moving the cat forward about 1" and the bung forward about 2", which will get the O2 in the clear. Previously, the rubber "O" hanger was pressing against the O2 sensor.

 

[Blue85]

So I got the rest of the exhaust together, started it up and found leaks at both ends of the cat and the front of the crossover pipe. I fixed the crossover and I guess I'll order more of those preformed stepped band clamps for the cat.

EDIT: Here's what I did for a new hanger and rear O2 location. You can see what my secret ingredient for sealing is:

But the good news - the stupid ticking sound is completely gone! If that was just the flex joint all the time, it's a wonder SLP was ever able to sell these things. Now the first thing I notice when I'm on the throttle is the supercharger whine, as God intended.

Also put new rotors and ceramic pads in the back. One side was obviously hung up, but I dealt with that. Brakes are pretty much acceptable at this point.

 

[Chevy305]

Those clamps are worthless, never could get one to seal. I usually mess with them enough until I'm so fed up I say F it and weld it tight.

 

[Stomis]

Those clamps are worthless, never could get one to seal. I usually mess with them enough until I'm so fed up I say F it and weld it tight.

Ive never had any luck with getting those butt clamps or band clamps to seal. Standard exhaust clamp, weld it, or go bling and do vbands.

 

[Blue85]

The one V-band in the system is leaking, so it doesn't encourage me to run out and spend big bucks on more. You know, I didn't even try standard U-bolt clamps on those joints, but they might work because the little slits are completely covered. The pipes just aren't perfectly round anymore, so some of this stuff just doesn't work. I don't want to weld everything together in case I need to pull the header or exhaust in the future - there has to be a joint somewhere.

I order 2 of these, since I had success with them on the crossover pipe. Should I rub them with copper silicone or something when installing? I've had some luck with that on collector flanges.

I wasn't expecting it, but the car is running a lot better. Somewhere between removing that 2.25" point and "back-blowing" the cat out, the throttle response is much improved. I did find some little metal pieces in the cat. I don't know where the rest of the piston chips went because the rear header was still partly welded to the cat when I got the car.

 

[Blue85]

I installed a new muffler tonight. The old was a Dynomax, which was straight-through with perforations and packing. It had been mounted very close to the rear bumper and pretty low. The old tailpipe was like 6' long with an S-curve that raised it 4" to put it in the factory exit location.

The new muffler is a Dynomax VT (moving parts in the exhaust goes against my better judgement, but it seems to be the only proven drone killer for these cars besides restrictive stuff). I mounted it higher up and further forward, basically in the stock location. The new tailpipe is straight 3", about 12" long. It is so much quieter - almost stock sounding at idle. I will report back after some extended driving.

BTW, those muffler mounting pins are a scrapped set of caliper slide pins off the Yukon.

The system is also leak free now, according to my stethoscope, so I'm good to go for tuning.

 

[jekquistk5]

Are you doing the tuning? Or are you taking it to a shop?

 

[Blue85]

Sooner or later I will probably end up with a tuning tool. I've been looking for a used one, but they tend to sell in 1 day. I probably should have bought one like 8 years ago. I tuned the K5 Megasquirt from total scratch, so I'm sure I could figure out how to tweak the existing tables on this car.

Right now the plan is to just drive over to ZZP, as they are local, have done hundreds of 3800s and have a Dyno. This way the tune can be like 95% dialed in an afternoon, instead of weeks or months trying to log over all loads, speeds, etc. on public roads. Plus I can get a dyno sheet. I'll have them do the CASE Learn and pull the ABS codes while I'm in there.

 

[jekquistk5]

Yah they go quick. My buddy used to tune his GSX with HP tuners. Was pretty easy but there were some things that were not right. Getting it 95% there sounds good to me

 

[Blue85]

After working on the car for 3 months, the week I finish is the week they are moving the dyno!

 

[Blue85]

Decided to get a little creative tonight and modified an IAT sensor. This is located in my lower intake, underneath the intercooler. The LIM is pretty warm - like 180F while running and the intercooler and supercharger are cool - I can hold my hand on them. The heat exchanger is basically at ambient, so it seems that my real intake temps with no boost should be close to ambient. However, with 50F air, the IAT is reading about 100F. Basically the more air is flowing through the engine, the cooler it reads.

So I decided to extend the IAT out so that it sits under the intercooler outlet instead of a corner of the LIM:

 

[FAB454]

How did the extension work out?

 

[Blue85]

How did the extension work out?

Oh yeah - it was a fail. It doesn't quite fit in the manifold. It would have to bend a little and I would surely break it during installation. Looking at a stock manifold, I see that this sensor is actually directly in the path of #1 cylinder.

Although my temps are running 50 degrees over ambient, they seem to get cooler the more I open the throttle. The intake manifold is basically at coolant temp and it must be heating the air. The intercooler and blower are just warm after a long drive, while on my non-intercooled car they are coolant temp (maybe more after a hard pull!). Since I'm only using low throttle so far, it's inconclusive. The real question is how hot it gets at large throttle and high boost.

 

[Blue85]

If you remember my issue with torque converter bolts, I came up with a solution weeks ago. I couldn't find another stock bolt, but I found basically the same thing at a hardware store. They didn't sell the right length, so I had to cut it and dress the end of the threads. The stock ones are on left and right, the new one on the top and Dorman one at the bottom. I swapped this in tonight. I hadn't seen any issues, but figured I should do it before high rpms (it's only seen 4000 so far).

Tomorrow it goes on the dyno!

Then...burnout ?

 

[Chevy305]

 

[Blue85]

It blew up today. I'm thinking to fill it with lead or pour gas on it and light it on fire.

Don't know when I'll post up again.

 

[Chevy305]

That's a shame

 

[Stomis]

It blew up today. I'm thinking to fill it with lead or pour gas on it and light it on fire.

Don't know when I'll post up again.

Holy wtf?!

 

[Blue85]

OK, I'm calmed down enough to post some information.

The car has been running fine, but I haven't been over about 35% throttle. When we got it on the dyno, the guy said the tune was pretty good and he did a quick pull to about 5500RPM. The car stayed at 11.5:1 up there and made about 275WHP/360WTQ. There was no knock retard (the enemy of L67/boosted builds), so he started adding timing and upping the shift points to hit about 6200RPM. About 20 more HP were expected, but didn't appear, so they were scratching their heads, but said to go ahead and swap the smaller pulley on since there was no knock retard and it wasn't even quite 8psi of boost at that point. When it started up again I inquired about the noise I was hearing. We turned off all the fans (to cool the car and dyno) and there was this distinct tapping sound, just like bottom end noise.

The tuner was sure it was due to the dirty engine, that the bearings must have been damaged even before I got it and the whole thing was just a time bomb. The logs showed good AFR the whole time, no signs of knock or detonation. They say that when the bearings start to go, they eat up power and that's why the power didn't come up for the 2nd pull. I posted pictures of that dirty engine on 3 message forums and not 1 person ever piped in to say it was a big risk.

The car did make it 30-some miles home and the oil I changed last night (Valvoline + WIX) clearly has something dark in it. I do need to check the torque converter bolts.... I just can't stand to look at it right now.