shrike Posted July 8, 2022 Share Posted July 8, 2022 1 hour ago, kpr said: So does it just get run open from the back of this or is Roman going to need to tie it into a resonator/muffler/ further exhaust? @Roman are you going to run this daily or only for the drags/track, do you need a cat for Wof purposes? Wondering how loud its going to be lol Quote Link to comment Share on other sites More sharing options...
kpr Posted July 8, 2022 Share Posted July 8, 2022 Will work as is, but will be extremely loud haha. lt will also work pretty much the same, with the correct exhaust/ mufflers after it 1 Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted July 8, 2022 Author Popular Post Share Posted July 8, 2022 Yeah so the cat converter rules are interesting. You could have one 2005 car that needs it, and one 2005 car that doesnt. Because it depends on the year the car was imported. In my case, no cat converter required. 14 Quote Link to comment Share on other sites More sharing options...
RUNAMUCK Posted July 8, 2022 Share Posted July 8, 2022 You know that a good straight through muffler makes more power than a straight bit of pipe? Because the perforated inside has less surface area than a straight bit of pipe, so theres less drag on the gas. 2 1 Quote Link to comment Share on other sites More sharing options...
kpr Posted July 8, 2022 Share Posted July 8, 2022 Yeah, flows more. but kinda means your exhaust is too small if makes more power. After the end of that pipe, idea is to simulate no exhaust. biggest straight through glass pack can fit straight after it. the rest of exhaust just needs to make it quieter, while adding little exhaust pressure as possible So yeah echo with 3" exhaust 5 2 Quote Link to comment Share on other sites More sharing options...
yetchh Posted July 8, 2022 Share Posted July 8, 2022 14 hours ago, RUNAMUCK said: You know that a good straight through muffler makes more power than a straight bit of pipe? Because the perforated inside has less surface area than a straight bit of pipe, so theres less drag on the gas. So really we should be running one 3" hotdog all the way from the manifold? 4 Quote Link to comment Share on other sites More sharing options...
RUNAMUCK Posted July 8, 2022 Share Posted July 8, 2022 Bigger isnt always better. If you read the exhaust thread, (If you can find it) a poster there said they found through extensive dyno testing to make more power with a slightly smaller diameter pipe. (Speeno decried it as BS because it contradicted his beliefs, but the same dyno should provide accurate data on the same vehicle) too big a diameter pipe, and the gas cools down/loses its velocity. On a turbo engine, the dump pipe off the turbo cant be too big. The bigger the pressure drop off the back of the turbo the better. As everyone knows, turbos aren't spoiled by gas flow, but by the residual thermal expansion of the gas. So having a gigantic pressure drop straight off the turbine wheel allows the gas to expand, and transfer that energy into rotational energy in the turbo shaft. A 3" pipe on say an SR20det, or a 4g63t makes sense. I'd honestly expect diminishing returns on an NA 1500cc engine. I'm happy to be proven wrong. 3 1 Quote Link to comment Share on other sites More sharing options...
Roman Posted July 8, 2022 Author Share Posted July 8, 2022 47 minutes ago, RUNAMUCK said: Bigger isnt always better. If you read the exhaust thread, (If you can find it) a poster there said they found through extensive dyno testing to make more power with a slightly smaller diameter pipe. (Speeno decried it as BS because it contradicted his beliefs, but the same dyno should provide accurate data on the same vehicle) too big a diameter pipe, and the gas cools down/loses its velocity. KPRs dyno testing shows exact opposite of all this on a variety of 4AGE combinations. 3" pipe gains power everywhere, over a smaller pipe. And actually surprisingly picks up the most gains in midrange. Then headers only makes slightly more power than that. About the gas losing its velocity, I've heard that mentioned a lot but I dont think this makes sense. Because if you double the rpm, you double the velocity of the gas in the pipe. So if this held true you'd expect a 3" pipe to gain top end when the airspeed is higher again, and lose midrange. But it doesnt happen, the opposite does. 5 Quote Link to comment Share on other sites More sharing options...
Yowzer Posted July 8, 2022 Share Posted July 8, 2022 On a properly designed exhaust, all the magic happens at the header / collector, the rest is just to get it out the back of the car. I reckon move the engine into the boot. 6 1 Quote Link to comment Share on other sites More sharing options...
ThePog Posted July 8, 2022 Share Posted July 8, 2022 50 minutes ago, Roman said: KPRs dyno testing shows exact opposite of all this on a variety of 4AGE combinations. 3" pipe gains power everywhere, over a smaller pipe. And actually surprisingly picks up the most gains in midrange. Then headers only makes slightly more power than that. About the gas losing its velocity, I've heard that mentioned a lot but I dont think this makes sense. Because if you double the rpm, you double the velocity of the gas in the pipe. So if this held true you'd expect a 3" pipe to gain top end when the airspeed is higher again, and lose midrange. But it doesnt happen, the opposite does. Fucks sake, where is the graph? 2 1 Quote Link to comment Share on other sites More sharing options...
GARDRB Posted July 9, 2022 Share Posted July 9, 2022 On 08/07/2022 at 10:31, Roman said: Haha yeah, I guess that's also assuming you could get that 18psi to ambient air temp. My solution to the problem, and possibly all problems, is simply to keep revving it higher. Lets just disregard that this is also the cause of all my problems Larry from Endyn who builds the crazy Honda motors says that RPM stands for Ruins Peoples Motors 1 1 Quote Link to comment Share on other sites More sharing options...
kpr Posted July 9, 2022 Share Posted July 9, 2022 It depends what you are calling the "exhaust" There is plenty to be gained getting the sizing right after the merge. Lots of people hit me with "such and such motorbike or race car doesn't run an exhaust that big" In a motorbikes case, just happens the length of bike is about the right place to end exhaust. same deal with race car. either the car ends or not a full length system. Banging a 3" pipe on right where all 4 pipes join together will probably loose power yes. but going big at the right place onward, is the way to go. I'll place money that most of the gains roman will see, is in the midrange along with a bit of peak power 9 Quote Link to comment Share on other sites More sharing options...
smokin'joe Posted July 9, 2022 Share Posted July 9, 2022 On 05/07/2022 at 09:25, xsspeed said: seems too much of a coincidence, is that the 3pot HRE was building? Jack Hawkswood maybe ? , as he seemed a bit unimpressed with his new car, which is sister-car to McKenzies, i believe Quote Link to comment Share on other sites More sharing options...
Popular Post kpr Posted July 9, 2022 Popular Post Share Posted July 9, 2022 yep runners made and welded. that was the easy bit, about 3 hours work. there is over a day just in the collector. just gotta weld runners to flange and stick the collector on and hope they fit haha 32 7 Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted July 9, 2022 Author Popular Post Share Posted July 9, 2022 Far out, looks so good! It doesnt look so worryingly long now that the 4 pipes are on there haha. Looks more like it belongs on an F1 car than an Echo 13 Quote Link to comment Share on other sites More sharing options...
kpr Posted July 9, 2022 Share Posted July 9, 2022 going by the pic of your exhaust, you should be able to still fit a reso after that abortion of pipes ^ 5 Quote Link to comment Share on other sites More sharing options...
Yowzer Posted July 9, 2022 Share Posted July 9, 2022 That looks like it's gonna sound bloody impressive 6 Quote Link to comment Share on other sites More sharing options...
Popular Post kpr Posted July 10, 2022 Popular Post Share Posted July 10, 2022 Done. Now a @Roman problem haha I'll quietly leave the room now. can sense the growing anger, due to the lack of graphs 39 6 2 Quote Link to comment Share on other sites More sharing options...
Popular Post Roman Posted July 10, 2022 Author Popular Post Share Posted July 10, 2022 Far out. I can honestly say I never thought I'd have a fabricated exhaust manifold of this quality, on ANY car, and I certainly never imagined I'd have one like this on the Echo haha. Cant express how awesome this is. Cant wait to get it finished and fired up! 16 2 Quote Link to comment Share on other sites More sharing options...
RUNAMUCK Posted July 10, 2022 Share Posted July 10, 2022 Either can the rest of us following this thread! 1 Quote Link to comment Share on other sites More sharing options...
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