When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
"Going to add a vband at the line in red so I can pull the downpipe without having to pull the radiator."
Why don't you weld a 3.5" vband at the end of your new beautiful elbow and continue the downpipe there (like a stock elbow+downpipe)? Maybe there is no room for the 3.5" vband?
no room due to ac compressor, but will look at options
In 4-cylinder applications with large tube manifolds I honestly don't think that 90* Placement would significantly negatively affect performance, it is seen quite often and I am sure it will work great regardless. The fab work looks very good considering the space you had to work with and there is very little "on the table" from what I see, thanks for sharing. My only other recommendation is that I would seriously consider getting it coated, insulation is a key aspect of performance.
Last edited by KingTal0n; May 2, 2019 at 04:33 PM.
Sorry, someone was confused regarding what I did for the oil drain. Although it may be hard to tell, in the pic below I have circled in red where the two pipes are not actually connected together and have ~1/8" gap between them. I will cut the tube coming from the turbo back ~1" (blue line in pic) and couple with a silicone tube to absorb small movement in the manifold.
Aluminum is brittle and it will fail, crack along the circumference, I see it in A/C lines fabricated all the time, even just from vibration. I like that you have included some spring-like damping/absorption, and I can appreciate the effort to make a custom 'hard line', however overall I feel that a simple hose clamped cooler hose works best, is typical OEM return line style because of reliability, is easy to inspect, immune to vibration related fracture, easy to replace (easier than AN fitting type deals), and superior in reliability even to braided hose which is not easy to inspect, can clog without warning, and tends to leak in oil return application for some reason.
Aluminum is brittle and it will fail, crack along the circumference, I see it in A/C lines fabricated all the time, even just from vibration. I like that you have included some spring-like damping/absorption, and I can appreciate the effort to make a custom 'hard line', however overall I feel that a simple hose clamped cooler hose works best, is typical OEM return line style because of reliability, is easy to inspect, immune to vibration related fracture, easy to replace (easier than AN fitting type deals), and superior in reliability even to braided hose which is not easy to inspect, can clog without warning, and tends to leak in oil return application for some reason.
In general aluminum is considered malleable, but the stress vs strain relationship of aluminum is dependent upon grade. Therefore, it is not accurate to say aluminum is brittle in general terms. Just because you saw an AC line crack along the circumference means nothing to me because that would actually suggest a filler rod issue. If I have a problem I will address otherwise I won't. Moving on to the compressor heat shield and adding the vband clamp to the front wastegate tube.
In reality, brittle or ductile is a state of the material, and a mode of failure. Allow me to quote a page from the book:
"Unfortunetely, there is no clear boundary between yielding (ductile type material) failure and fracture-dominant (brittle type material) failures. Indeed, classification of many materials as ductile or brittle is meaningless unless physical factors such as temperature, state of stress, rate of loading, and chemical environment are specified. For example, many materials can be made to behave in a ductile manner for given set of conditions, and in a brittle manner for another set of conditions. To be mmore precise, one should speak of a material being in a brittle or ductile state. "
-page 547 Advanced mechanics of materials
I am suggesting an aluminum oil return tube will behave as brittle in this example because it is exposed to a wide range of conditions which typically cause Aluminum to behave in a brittle manner. For example, the chemical environment both internally and externally (oil, acids, atmospheric content), effects of temperature over time (heating/cooling), modes of vibration. The Aluminum oxide superficial is also classified as "brittle" and crack forming with very little ductile strain, meaning a crack in the oxide will create a stress concentration, snowballing quickly to complete failure in a brittle mode (a sudden break, with very little bending or 'ductile behavior' evident)
Finally, an important distinction between ductile steel and ductile aluminum is the fatigue limit,
e.g. quote,
"Aluminun has no fatigue limit, constant exposure of aluminum to repeated loading will ultimately lead to failure, no matter how low the actual stress magnitude experienced for all practical purposes"
file:///C:/Users/TaliNg/AppData/Local/Temp/ProBoat-June-July-2012-Aluminum-Welds.pdf
An oil return is subjected to several types of stress, nearly all of them. It's loaded physically, vibrated, chemically attacked, etc... just a poor choice of alloy for the location IMO, given how easily a hose could be fitted.
I think it is safe to say that the OEM manufacturers are typically using steel with rubber oil return for these reasons. And that failure is going to be experienced eventually no matter what you do in this application.
It might also last a long time, who knows. Its just my super-cautious nature when trying to build a reliable car, if you start putting 'maybes' all over the place, one or two of them could turn into 'oops'. And an oil return drain is not a place to have an 'oops' when a $14 hose could have prevented it. $.02
May 2, 2019, 04:29 AM
