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This article was first published in 2000.
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It was a sad day for Georgina when she decided that parting with her Nissan EXA turbo was necessary. She had loved it but when the doortrims were removed to test speakers, and when the wastegate hose was removed to test engine longevity, and when the exhaust fell off - well, there are some things that only an elephant can bear. Elephant? Yup, the buyer was none other than Edward the elephant.
Wow! Edward had never had a turbo car before. The shrill whistle of the turbo, the roar of the exhaust, the orange day-glo instruments - this was a car suitable for a macho elephant indeed. But Edward hadn't been driving the car for more than few hours when he realised that something was very wrong. That piece of pipe lying on the driveway back at Georgina's house must have come from
his car! The exhaust wasn't loud because this was a turbo car; the exhaust was bellowing because it stopped halfway along under the floor. That muffler that could still be seen at the back of the car
wasn't even connected to the engine!!
And not only was the exhaust terribly loud - loud enough to hurt an elephant's large and sensitive ears - but it was probably also horribly illegal. And the last thing that a law-abiding elephant wants is to be pulled over by the police... Edward thought he'd better check, and got out his SPL meter. With help from his lady elephant (no you can't see her - she looks the same as Edward but she doesn't have an, er, trunk) he measured the SPL at the back of the car while Florence revved the engine to 3000 rpm in neutral. 92dB(A)! Aaaaagh, no wonder his big flappy ears were hurting.
But how hard did his turbo powerhouse go with only the front part of the exhaust in place? Edward pushed the wastegate hose back onto the turbo (whatever had that Georgina woman been thinking of when she disconnected it?) and drove the car to an empty stretch of road. He carefully put his AC22 Performance Meter on the dash and launched at 3000 rpm. Hmm, he nodded his elephantine head, hmmmm 9.83 seconds. Elephants want to make sure of these things so he turned around and ran another time in the other direction. 9.71 seconds, this time.
So Edward needed a new exhaust - urgently. But what could he do? He'd given that nasty Georgina all of his money - and she'd sold him a defective car! A new exhaust would cost him heaps - how on earth could he pay for one? Being a methodical elephant, he sat back and pondered the problem. And then after a while he opened another bottle - and then another - and pondered further. "The EXA has as standard 77 kilowatts," he sipped. "That's not very many" - for a moment his head lolled back as he thought dreamily of the WRX he would one day own - "so surely I can get some mufflers off another, more powerful car - and use them?" After all, out the back of Exhaust Technology he'd recently seen a whole heap of discarded original equipment mufflers!
Time to make a phone call. Edward dialled 8272 7500 (or 08 8272 7500 for interstate elephants, or + 61 8 8272 7500 for Indian or African elephants) and spoke to the friendly Mr Mark. "Mr Mark," said Edward. "Can I came along and test some of the mufflers you have out the back? Please?" - for Edward can be charm personified when he sets his mind to it. Mr Mark was obliging and so Edward started thinking about flow testing techniques. How would he test the mufflers? The last thing he wanted was to get a secondhand restrictive muffler fitted to his EXA.....
Edward walked around his house, confiscating several items from the outraged - then petulant - Florence. He grabbed a vacuum cleaner (which had a www.autospeed.com sticker on the side - God knows what that means, thought Edward), some clear plastic hose, an empty Coke bottle, some masking tape and a piece of old wood. Showing again his careful, methodical nature, Edward also collected a pen and paper before he set off in what he now thought of as the outrageously loud EXA.
Mr Mark - and Mr Mark's helper, Mr Ed - greeted Edward effusively, making all of those old elephant trunk jokes that he had come to expect: such irreverent blokes, these. Sidetracked on the way in by the electronic games machines placed invitingly in the waiting room, Edward kicked some virtual butt before remembering that while he might live for ever, these mere humans needed to get something done every day of their lives - and he was there as their guest. So he collected all of the gear from the EXA and strolled out the back.
Wow! Look at all of those mufflers! Mufflers piled here, mufflers piled there, complete exhausts even! Edward sorted through the stacks, looking carefully for mufflers that had pipe diameters of at least 40mm (1.6 inches for Imperial elephants). While he didn't expect to use a pipe diameter quite that small, those little mufflers would give a good comparison. Edward sorted and selected, ending up with eleven mufflers and two further complete car exhaust systems. What fun this was!
But how was he going to test the flow of his new finds? He scratched his head, flapped his ears and abstractly snuffled his trunk at a passing female elephant. What had his idea been again? Then he remembered! He filled the Coke bottle with water, right to its brim. He inserted the piece of wood into the vice of an old woodworking bench that happened to be there (good thing the back of Exhaust Technology adjoins a demolition yard, he thought happily) and carefully positioned it so it was angled just a bit above horizontal. Edward then attached the clear plastic hose along the length of the wood, holding it in place with masking tape. One end of the hose he stuck into the Coke bottle, the other end he attached to the pipe leading to the vacuum cleaner nozzle. Using his trunk, he blew the bubbles out of the hose and then he turned on the vacuum. Oh, this was wonderful! When he blocked off a bit of the open vacuum cleaner nozzle, the water level was drawn up the hose. Uncover the nozzle and the level went back to a point Edward called the baseline. Now he could measure the flow restriction of all of these mufflers!
Trembling with excitement, he put the first muffler on the flowbench. (Because that's what Edward had started calling this collection of junk - a 'flowbench'!). He sealed the vacuum cleaner nozzle to the muffler pipe and switched on. The water level in the inclined manometer (cos that's what Edward reckoned this part of a flowbench was called) rose to 970EU (that's 970 elephant units). Hmmm, thought Edward, that's not very good. He picked up the muffler and looked at it more closely. It was designed for 42mm pipe and had 'Daihatsu' written on it. Prob'ly a Charade muffler, Edward thought.
Edward selected another muffler. This one had 'Mitsubishi' stamped into its sheet metal and used a larger 53mm cast inlet pipe. The manometer reading was 800EU - 170EU lower than the Charade muffler. This muffler was flowing lots better! Slowly and carefully, Edward worked his way through the mufflers, testing each one twice in case the baseline was changing as the vacuum cleaner warmed up. One problem did concern Edward, though. As the guys inside the workshop switched on grinders, Edward's big, flapping ears could hear the vacuum cleaner note changing, as it altered in speed slightly. So Edward made readings only when the grinders were off.
After about half an hour of testing, Edward had the results for all eleven mufflers. Unfortunately a lot of them he couldn't identify - what did an 'M' stand for, he puzzled? But anyway, it didn't really matter what the new muffler for the EXA was from, as long as it flowed well and was quiet. And what factory muffler isn't quiet? Edward asked himself rhetorically. The industrious elephant's table of results now looked like this:
| Edward's Muffler Number |
Tube Diameter (mm) |
Flow Restriction (EU) |
| 1 |
49 |
590 |
| 2 |
42 |
970 |
| 4 |
47 |
660 |
| 5 |
51 |
900 |
| 6 |
45 |
790 |
| 7 |
47 |
760 |
| 9 |
48 |
590 |
| 10 |
53 |
650 |
| 11 |
42 |
800 |
| 12 |
58 |
550 |
| 14 |
63 |
550 |
The lower the number of Elephant Units, the less restrictive Edward knew the muffler was. So he looked with particular attention at mufflers #12, 14, 1 and 9.
But what about testing a complete exhaust? The EXA was so noisy that Edward wanted an exhaust that was really quiet - so quiet that not even Florence's big ears would be able to hear him coming home. And Edward figured that meant using a resonator as well as a rear muffler (Edward's EXA is pre-1986, so doesn't need a cat converter). When he'd been doing his digging through the piles of discarded mufflers, Edward's trunk had snuffled out two complete exhausts. One 47mm system was from a Nissan 180SX fitted with the 2-litre turbo (Edward was sure of that cos there was one such car in the workshop at the very time he was doing his flowbench work!) and the other? Well, it also looked Nissan and used an even bigger tube size - 65mm. Edward flowed both systems and found that the stock 180SX system had a figure of 535EU while the other (larger!) system was much worse at 880EU. Hmmm, the stock SR20DET 180SX exhaust (resonator, pipework and muffler) flowed better than many of the mufflers tested on their own! And wouldn't it be nice, mused Edward, to have a Nissan-branded exhaust on his Nissan EXA? Of course new pipework would need to be made, but still....
Edward shuffled in to see the nice Mr Mark. Could a humble elephant have the 180SX exhaust? he asked. But Mr Mark frowned, and said something about the system being good for temporary replacements on cars fitted with yellow stickers. Hmm, thought Edward. What about this one then? He pointed at another complete exhaust, and Mr Mark nodded his head. Yes, Edward could have that. Edward could have hugged Mr Mark - but he didn't cos he didn't want everyone thinking that he was a kinky elephant. Plus Florence could always amble by at the wrong moment... The selected exhaust was one with 'Holden' stamped on it, and Edward guessed that it was from a late-model Commodore. Edward had in fact already flow-tested its components (the exhaust pulled apart at a slip-joint) and had found that both the muffler (shown here) and the resonator had only teensy-weensy restrictions. In fact, they were #12 and #14 in the table above.
Oh joy of joy - Edward had found his mufflers. He packed up the vacuum cleaner and other paraphernalia and rushed home to tell Florence the good news! But he found her sweeping the carpet, a cross frown on her normally beaming face....
Next week: Edward the Elephant supervises as Mr Mark installs the new system on the EXA.
Contact:
Exhaust Technology
(08) 8272 7500
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