I've been trying to think about where the ideal location for the muffler would be. I don't think it should go in front of the O2 sensor, for somewhat obvious reasons, but I can't move the O2 sensor forward in the stream unless I want to sample from only one bank, which isn't ideal. Between the O2 sensor and the elbows just in front of the first muffler is maybe only 14-16", so not much room to put anything meaningful except for a cat, and that might be too far back for the cat to properly light off and stay lit (even the O2 sensor is too far back, but at least it's heated so it works). Cats can't go in front of the O2 sensor, though that would be the best place for them - in the downpipes just in front of the merge.

The REAL problem is that I used too big of a main pipe. Good header design suggests that the total combined primary area (inside diameter) should be between 1.15 and 1.75 times the collector area. Mine is around 1.25x. Going on the same proportions, the two 2" pipes should dump into a 2.25" pipe, not a 3" pipe (which I had a lot of, which is why I used it). 2.5" would even be a little overkill for this car. I think that to fix the problem, I'd use 2.25" pipes and rearrange the Y section a little to get a cat up front a bit sooner, and maybe make my own muffler that takes up all the space between the rear bulkhead and the suspension. The original idea was to make it as smooth flowing and even left-to-right as possible, damn the noise - full speed ahead!

In any event, no... I haven't sold it yet Rabin.

Or you could supercharge it and make use of the 3" exhaust as is. I've always like the Rotrex ones. http://www.rotrex.com/Home.aspx

I'd agree on the 2.25 - That should support a good 250 HP no problem. I wonder if you could use something like this in the system to quell the rasp: http://www.dynomax.com/mufflers.php?muffler=vt

Review here: http://www.motoiq.com/magazine_articles/articletype/articleview/articleid/2142/dynomax-vt-muffler-dyno-test-does-quiet-mean-slow.aspx

Rabin

Is there any area right behind the bumper? 2.25 sounds about right to me, if you're going to do some cam swaps and playing then maybe 2.5 would be more right. Why not put a resonator at the back and a couple of oval straight through's up stream of them?

There are mufflers currently in both of the conventional muffler spots. There isn't much room within those areas for more, unless they were custom built. I wonder if there's a forum for custom mufflers? A single 2.25" is good for over 200 hp and I doubt I'll get much above there with the stock fuel system and my configuration, no matter HOW good the DMC cams are. And I'm not even sure I'll drop the $600 on them and then modify things so that they'll work in an evenfire configuration.

Bean - ummm, never heard of those. Interesting. The C30-80 looks like it would fit the bill nicely, but if it were my dollars and money I'd use a turbo. I did notice the VT when I was looking at mufflers but I don't trust the spring-and-flapper design to stand up to heat & vibration. Maybe it will and maybe it won't but I'll wait and see. I'd rather something without any moving parts... I haven't driven it enough in the current configuration (around the block, basically) to know how I feel about it anyway, so no sense in spending money just yet.

I was suspicious of the flap longevity as well, but it is used in OEM's, and it is a stainless muffler so in theory it should be decent. Functionally I think it'd be perfect for restricting or damping exhaust gas velocity without a major change to your system. Muffler is pretty cheap so not really a lot of investment to experiment and it'd be dead easy to install.

I only suggested Rotrex with the engine staying in a stock configuration. "High" compression low boost (~5-7 psi maybe) set up with the engine totally stock. I also like that it's very linear in it's boost so much easier not only on engine internals, but great for drivetrain too.

Turbo is definitely the way to go if you're going for big power, but then you have to redesign the headers and do the downpipe, and you'd have to build the bottom end to go for decent psi.

Mostly spit balling ideas though - it's fun to have good discussions with enthusiasts that build some really well thought out set ups.

Rabin

Yeah but...

With 5-7 psi you are as hard on the bottom end with a turbo as with a super (just as much, or as little, need for beefier internals). With a turbo you have wonderful midrange torque to go along with the top end (centrifugal superchargers are all about top end power and sometimes make LESS bottom end due to near-zero boost to offset the drag on the engine) With a turbo I'd build up a Y pipe between the manifolds, a downpipe and a new midpipe, and it's done. With a turbo all I have to do is tap into the engine oil supply, and don't need to plumb in a secondary oil supply/cooler for the super. I wouldn't have to build a bracket to mount the super rigid and square to the engine, sacrifice air conditioning for space to mount, it or re-work the whole front end for a serpentine belt. With a turbo I don't have to change the cam like I would be tempted to for a super and it's need for much greater exhaust flow. And mostly: I could choose from the 4 or 5 turbos I have on hand, rather than drop a couple grand on shipping a supercharger "system" to me. And remember, I'm not exacly starving for space behind this engine - up front is another story!

With all that being said, I do like the idea of superchargers (never driven one) and the centrifugal would protect the bottom end by not building boost down low. Supers put drag on the engine but with the right camshaft they can be very efficient. If I'm going through the hassle of forced induction, remapping the FI and ignition, and all that, Turbos still get my love.

So with the whole "turbo vs. SC" thing started..

I read Dynomax's literature (or was it that article) where it said that the flap was used in OEMs, but that doesn't really thrill me either. I may be baselessly cynical but I believe the OEMs will do things that work long enough to last most of the way through a 3 year lease, and that's about it. Most people don't notice gradual changes, and if the spring in the exhaust starts to soften up as it ages with heat, I'm betting that nobody notices unless they park their car next to something identical, and then they probably say "mine sounds better!"

But the sound clips of the ultraflow welded sounds awfully familiar, aside from the whole V8 thing. At least you can GET a big VT, not that I have much space to fit it.

I agree with all your points. All depends on budget, time, fab skills, and your build goal.

When and why - are up to the owner to determine what works best. For me if I wanted to add some extra power to stock motored car, then the SC gets my nod. I drove a 1.8L Miata with a SC and was astounded with the instant throttle response and the "v8" power delivery. I've wanted a SC car ever since.

That said - I'm way more of a turbo guy myself and am really wanting to upgrade my 505 turbo with the new Borg Warner EFR6258 - it's a really nice bit of kit. I've got a T3/T4 built by forced performance - but I'm a torque junky that wants as close to instant spool as possible. Big high end power is nice too - and the new EFR turbos are pretty darn good for rapid spool AND can still put out decent power. Just a fast road build - so having super fast spool is my biggest priority while still not running out of air at redline.

VT muffler - at it's price point I figured it might be worth a gamble just to see. If you can find a solution with no moving parts though - that's obviously the way to go. Something like this maybe after the "Y": http://www.sweet-thunder.com/chambered_general_main.html

Pretty sure others make it - but that was the first link I found that described what I had seen before.

Rabin

Okay, so anyway, on to the A/C work.

When I got it, the car had all the A/C stuff except for the compressor, dryer, and the low-pressure hose from the dryer to the compressor. I'm not sure where they got to or why they were removed, or for how long they were missing, but I tied down the high-pressure hose, and ran it like that for a few years. Since then I collected a used dryer and evap-dryer pipe and a new dryer-compressor hose. Dale's red car donated the compressor... I think. I'm not sure where mine came from really but I had a couple and this was the best of them. I got a new dryer, a new R12 orifice valve, and a R12-R134 retrofit kit from FCP Groton, and forgot about them for at least a year.

This winter one of my only tasks was to finally get the A/C working. I'd decided pretty early on that I was going to use Dura-Cool for simplicity, and I gave a list of reasons for the decision earlier in the thread. Here are some details of what I've done:

The first step was to clean everything. Brakleen was recommended by Art at Cool Earth, as it's cheap, has great cleaning properties, and is a hydrocarbon so any residue is not going to mess up the system. I had a pretty good sized bottle on hand, so I went to town:





I scrubbed away at all the hoses, the silencer, and cleaned off all the sealing surfaces. I flushed out all the hoses and the silencer with brakleen and then blew them out a couple times.

Then, after removing the orifice and hooking the HP line back up to the evaporator, I filled the evap through the LP return nozzle and blew it out with shop air. This blew the brakleen through the one hardline I couldn't easily remove, through the condenser, and out of the fitting that would drop into the silencer once it was reassembled.





I used about half of it. I was getting some nasty looking fluid in my catch pan:



But I kept going until it came out clean. I then blew it out for 5 minutes straight, hoping to get all the residue. I reassembled the system using the new orifice, dryer, and all new seals except for the one that I couldn't get to without removing the front bumper.

Following Art's instructions, I poured 2 oz of Dura-Cool's Oil Chill lubricant into the dryer, 2 oz into the evaporator, and 3 oz into the HP line coming out of the compressor (which pools in the silencer just before running through the evaporator. His rule of thumb was 2 oz for each of the exchangers, 2 for the dryer, and 1 oz for each 10 feet of hose. Then the compressor went on and 6 oz of Oil Chill was poured into it: 2 or 3 oz into the inlet fitting and the rest into the reservoir. There isn't much magic here apparently - it'll all equalize is what he told me.

All buttoned up:





Oh yeah, and I scrubbed away at the compressor pretty good too. I pulled off the clutch assembly and painted it up while I buffed the compressor body with a progression of scotchbrite roloc discs. No fancy polishing here, just some good mechanical cleaning.

Because of the mix of Eagle and Volvo parts, I was forced to do some fabricating when it came down to the bracketry. The Eagle has a different way of mounting the compressor, since it uses a serpentine belt arrangement, but because I foolishly used the Volvo V-belts, I needed to come up with some form of tensioning device. It was pretty simple - a tensioner from a Ford A/C system and a bodged together slider strut. It's all solid as a rock and lined up properly so I'm pretty confident that it'll go the distance. I failed to take any pictures of this so far.

Anyway, once it was all buttoned up I gave the compressor a bunch of turns by hand to make sure it wasn't hydraulically locked, per Art's instruction, and pressurized the system with shop air to see if it would work. And it did! Clicked on and off nicely, the compressor ran quietly, and all appeared to be working well. I left the system pressured up for a week and it did bleed down a bit, so I went over all the fittings with soapy water and found a slight trail of bubbles coming from the brand new R134 fill fitting I got in the seal kit! A quick twist of the schraeder valve and a bit more air pressure, and 3 days later no difference. Sealed!

I booked the car into Cool Earth's install bay (officially named My Automotive Shop... really!) and got them to pull a vacuum, purge the system, and pressure it up. I could have done this last part, but I'll keep my cans for top-ups, in case of any leaks too slow to detect over a 3 day period. Art pulled a vacuum for 2 full hours before his gauge bottomed out - you pull a vacuum to boil off any moisture in the system, which will freeze and collect in the orifice & render the system dead until it thaws out - and left it there for another couple hours to verify that it was still sealed up. All seemed well, so he purged it with inert gas (you'll want to start charging at around atomspheric, I believe, but you want to keep all oxygen out of the system) and then charged it with Duracool R12A replacement refrigerant. He ran it hard for a while to ensure system operation and no freezing, and he declared it to be in great shape. 38 degree outlet temps and a quiet compressor (and poorly hidden amazement that an '88 Volvo could look so good).

The vacuum/purge/refill cost me $190 after tax, but I'm happy about spending it there. I don't have the equipment to properly vacuum the system (it needs to go to about 28.5-29 inHg, the car's motor only pulls about 14" and the car coupled with a cruise control vacuum pump only pulled about 22") so at least I know it's done right, and have a more experienced eye tell me that the job was done properly.

Thanks very much for the write up! I've mostly thought of the AC system to be something I'd get done - but doing it this way seems pretty straight forward.

Please update as the summer progresses as I'm curious to hear how good it is on a hot da

Rabin

I believe I owe you some downpipe pictures too, don't I Rabin? I'll be swinging it into the garage for an oil change and minor attention this weekend, so I'll snap some shots.

The A/C is a pretty simple system, it's the lubricants and refrigerants that make it more complicated. If this Dura-Cool stuff is as compatible with R12 and R134 components as the literature says, I think that makes the choice pretty easy. If it performs as well as the literature says too, so much the better.

I did flick it on last night on my way home, just for giggles. It was still pretty chilly out but the system started blowing COLD air pretty quickly. But I'll tell you: in a 5300 lb, 265hp/350ft-lb truck, you don't notice the compressor kicking in. In a 3300 lb, 150hp/200ft-lb car, you do. I imagine it'll register on the old fuel economy...

Because my car is the Dark Side, he is charged with (ssshhhh) propane at the moment. My buddy Craig has a pretty good set up for doing A/C work in his garage. I know very un-tree-hugger of me, but after I paid Paul to re-charge it the system had leaked dry (due to my banging around A/C lines during engine work) and I wasn't about to do anything fancy. Who knows how long it will last, but it works great for now!

BBQ propane or Dura-Cool propane, Athal?

Pics will definitely be appreciated - thanks.

I found the local Dura Cool distributor in Regina but no idea if they actually do the purging and such. I wonder if the local AC shop is willing to use the Dura Cool stuff?

One could almost argue Propane is more environmental that refrigerant - but then discussion turns to safety. I don't really have any qualms with the safety aspect since the volume of gas is so minimal. For me it's much more important from both safety and environment aspects to make sure the system is leak free.

Matt - does your car have idle bump adjust for when the AC is on? Won't help with the economy hit - but should make it less noticeable.

Rabin

According to Greanpeace (apparently), hydrocarbon (propane) based refrigerants are better for the environment than R12 and R134. I'm not about to chase down the source of this, but it's what the Dura-Cool website states.

And Dura-Cool also states that the flammability aspect of their product is a non-issue, as R134 has a lower flash point than Dura-Cool R12a does. I don't know what the oxygen/fuel ratio tolerance of either is, though. But yes, one way or the other until and unless it gets out of the closed A/C system, either refrigerant is "safe".

The Volvo has a constant idle system. When warm the car idles at or around 750 RPM regardless of it being in gear, A/C on, or not. I can feel the power being sucked away when driving down the street, though, so whether or not the idle is consistent, it's still burning more fuel.

I guess the plus side is that it should still not be as bad as said 5300 lb, 265hp/350ft-lb truck on fuel even if the AC is on and you're down on power...

Rabin