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Old 08-02-2016, 03:25 PM   #321
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Does that mean Cobras sound like Ford Fiestas?
Are their exhaust systems built without a crossover pipe?

(Honest question- I know the original 60s era cars were, but I assume the newer ones defer to physics.)


I've only heard two "Cobras" in real life, both of which were replicas. One had a 427 side-oiler in it, can't remember the other. But they both had huge carbs and what their owners charitably refer to as "lumpy" cams, meaning that they sounded like **** pretty much all the time.
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Old 08-02-2016, 03:27 PM   #322
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Quote:
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Are their exhaust systems built without a crossover pipe?

(Honest question- I know the original 60s era cars were, but I assume the newer ones defer to physics.)


I've only heard two "Cobras" in real life, both of which were replicas. One had a 427 side-oiler in it, can't remember the other. But they both had huge carbs and what their owners charitably refer to as "lumpy" cams, meaning that they sounded like **** pretty much all the time.
Nope. Straight out the side.
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Old 08-02-2016, 08:29 PM   #323
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Guess it depends on what era you grew up in, lumpy sounding cams are sweet music to some ears.
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Old 08-02-2016, 08:54 PM   #324
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I guess... Personally, the sound of a turbocharged flat-plane V8 which idles like a Honda and yet makes all the torque gets my panties a whole lot wetter than something that sounds like four Harley engines tumbling around in a washing machine.
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Old 08-02-2016, 09:10 PM   #325
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So, is teh plan to cover all that up with a fairing, or...?
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Old 08-02-2016, 09:52 PM   #326
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What diameter pipe did you use coming out? 2 1/2? That's what I was planning. If the bends got to tight, I was going to fall back to 2 1/4. V8R's down pipe looks nice, but I can fab my own for much less than what they are asking. The problem was I couldn't find somebody who made the flanges in stainless, so it's going to be mild steel.

Looking at how to square the end of the pipe. Might be easier to crimp first and trim to the edge instead of crimping on the edge.
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Old 08-03-2016, 02:28 AM   #327
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What diameter pipe did you use coming out? 2 1/2? That's what I was planning. If the bends got to tight, I was going to fall back to 2 1/4. V8R's down pipe looks nice, but I can fab my own for much less than what they are asking. The problem was I couldn't find somebody who made the flanges in stainless, so it's going to be mild steel.

Looking at how to square the end of the pipe. Might be easier to crimp first and trim to the edge instead of crimping on the edge.
Material cost is naturally less than that of a fully produced part but if I was doing a traditional out-the-back exhaust I'd have used the V8R downpipes no question as it'd have saved me a good chunk of time.

2.5" on mine, I don't doubt that 2.25" would be completely adequate as well but I always try to future-proof things if possible, so I went on the larger end of the spectrum in case I get ridiculous with the motor down the road. Flanges are mild steel, I couldn't find them in SS either. Used 309 rod to weld the pipe to flange and the whole thing is going to be ceramic coated so I'm not too concerned (though the coating will probably wait until later this year).

It's a good plan to crimp just a half inch past the end of the bend instead of in the bend. The first side I did in the bend and took a good 3 hours to shape because the inside of the bend is seriously stubborn and has tons of spring-back. The second side I left a half inch or so past the bend to work on and it made it considerably easier.
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Old 08-03-2016, 02:37 AM   #328
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So, is teh plan to cover all that up with a fairing, or...?
Not entirely covered, but partially. The skirts will serve several aero functions as well as move air down the rocker to continuously pull exhaust heat away. An improvement over my last set of sideskirts, it's always an evolution
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Old 08-04-2016, 01:08 PM   #329
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damn, that's nice!
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Old 08-04-2016, 02:04 PM   #330
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^that photo belongs in one of those photo collections of OCD-satisfying photos.
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Old 08-04-2016, 08:50 PM   #331
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How much does the engine move around? My only concern would be the exhaust rattling around. Nice work though. Looks like you formed it by pressing it against the body. It reminds me of working with a aluminum fuel line. Just put it the corner, press it with you hand and thump it in with your palm. If only making exhaust were that easy.
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Old 08-04-2016, 11:46 PM   #332
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That's my question as well. That's all beautifully tetris-ed in there. What happens when the engine rocks? Is there a flex joint I'm not seeing somewhere?
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Old 08-05-2016, 03:02 AM   #333
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Everything is pending testing, of course. But, these engine mounts allow far less lateral motion of the engine than we're accustomed to with standard-style mounts. The exhaust bushings I chose dampen vibration but hold everything solidly in place, they don't allow movement anything like standard rubber hangers, which you wouldn't want for an exhaust like this where fit is tight. I can always make adjustments if necessary of course. If a flexpipe proves necessary, I have a plan for it's location but it would require some more clearancing of other parts to make it fit, which I'll be happy to avoid if I find it isn't necessary.
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Old 08-05-2016, 03:29 AM   #334
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I'm surprised by how little the engine rocks free-revving - like, less than a quarter of an inch at the top of the manifold. I think you have an 80% chance of getting away with it as is.
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Old 08-05-2016, 06:52 AM   #335
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any chance of some close up imagery of the exhaust mounts you have used?

Last edited by BEAVIS; 08-07-2016 at 05:46 AM.
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Old 08-05-2016, 05:51 PM   #336
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Link to the grommets at Summit: https://www.summitracing.com/parts/stw-exgro




This is my first time using them but I think they'll do just what I need. They're more of a vibration isolator than a traditional hanger that allows movement.

Also available on summit from the same brand are SS hanger tabs which use these grommets, but of course I made my own tabs. Word of caution, drilling out 5/8" holes in 0.125" SS is one of those exercises in supreme patience.
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Old 08-07-2016, 05:28 PM   #337
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So Ryan, when are we going to be able to hear it? Mine is a bit away from being started, since money constants. Even though I started mine before yours.
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Old 08-13-2016, 10:32 PM   #338
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Interesting, got any data on the intake flow? What is telling you the intake and/or throttle body are the restriction?

I won't be doing anything like this for now, need to get good baseline numbers before tweaking bits for any additional power. I have a few things in mind though.
It seems that after people with the V6 Camaro's are doing a ported throttle body they are gaining 10-15 whp, then the intake is a restriction.
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Old 08-14-2016, 12:03 AM   #339
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So Ryan, when are we going to be able to hear it? Mine is a bit away from being started, since money constants. Even though I started mine before yours.
No set date, I think the best way to approach a project of this size is to allow for taking one's time to do things right if you have the luxury of not needing to be done by a certain deadline. That said, I'm some amount of time on it almost every day so it is moving along at a good pace. Still have wiring ahead.
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Old 08-14-2016, 08:54 AM   #340
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The only thing I did for my driveline was the 8.8 conversion that a friend did for me for $200. But everything else is to just get over peoples favorite hurdle, Starting the Engine :-) .I got one more modification to do to my stock cross member and the engine will be in its home. I am not doing frame rail connectors either.
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