What is a Japanese manifold? Topic is solved

[j-dawg]

This recent discussion about exhaust manifolds is informative http://volvospeed.com/vs_forum/topic/17 ... ison-test/

That thread hurt my brain to read.

There's a huge amount of folk science in automotive performance tuning, and as a collective audience we, the enthusiast community, are embarrassingly gullible. Someone reads something in a fluids textbook about minor losses and writes on a car forum about it, then everyone's falling over himself to spend $400 on a part with "less bends" because "bends restrict flow". Meanwhile, nobody does real analysis, with math, of the actual application, nobody does a dyno test, everyone's got an opinion, and the world is a little dumber. Examples: "reverse intercooler piping" kits, the obsession with mandrel bends in exhausts.

A flow bench test could demonstrate that one can put more gas through a manifold, but it would not demonstrate that that capacity is being used to any benefit in an exhaust system. I don't think anyone could conclusively put the question of whether a particular manifold helps performance without doing two dyno tests. But I don't doubt that people will continue to have strong opinions about which is best.

[abscate]

Applying the east coast translation guide to this....' Folk science' becomes "' idiots'

Idiocy isn't not knowing stuff, it's not knowing what you don't know.

[erikv11]

This recent discussion about exhaust manifolds is informative http://volvospeed.com/vs_forum/topic/17 ... ison-test/

That thread hurt my brain to read.

There's a huge amount of folk science in automotive performance tuning, and as a collective audience we, the enthusiast community, are embarrassingly gullible. Someone reads something in a fluids textbook about minor losses and writes on a car forum about it, then everyone's falling over himself to spend $400 on a part with "less bends" because "bends restrict flow". Meanwhile, nobody does real analysis, with math, of the actual application, nobody does a dyno test, everyone's got an opinion, and the world is a little dumber. Examples: "reverse intercooler piping" kits, the obsession with mandrel bends in exhausts.

A flow bench test could demonstrate that one can put more gas through a manifold, but it would not demonstrate that that capacity is being used to any benefit in an exhaust system. I don't think anyone could conclusively put the question of whether a particular manifold helps performance without doing two dyno tests. But I don't doubt that people will continue to have strong opinions about which is best.

Maybe you mean: we're participating in internet forums, keep that in mind.

For me the take-home from that thread is that any performance advantage of the R manifold is unclear. But what's clear is it doesn't crack as much.

[jimmy57]

Manifolds often are sourced from turbo manufacturer on many makes. Carmakers L O V E packaged parts supply deals. caliper-rotor-master cyl-booster-abs are almost always single source any more as one example (R models excepted due to Brembo wheel brake parts but the same hydraulics and ABS).

[beigg]

Most go with trendy parts just for simplicity. Not everyone is aiming for record setting achievements, just more performance at tried and true things on the market.
For these volvo's, I will say I find myself spending more time seeing what can fit versus what will provide the most performance, just because I dont want to deal with it again later because it caused issues with something else later on. [sarcasm] Good thing the tuning aspect hinders the ability to really dig into the performance! [sarcasm]

[Sommerfeldt]

I've got a 921 on a shelf as well... would be fun if that VS thread actually lead somewhere with actual numbers from a dyno. But it looks like it stalled out. Needs more flow...or maybe it's all hot gasses... [ba-dam-tss]

- G

[beigg]

that thread did run outta steam. What a waste to a potential gateway for flowing information ... just prematurely dumped.

[erikv11]

Haha and I thought the VS posters were harsh!

To be fair, swapping exhaust manifolds and testing both setups is a pretty tall order when everyone acknowledges the differences are likely small at best. But hey, maybe it's not always important to be fair.

[beigg]

Measure of performance can be trumped by effort, at least from what im told.

In all reality, a tuned header just isn't feasible for a daily commuter that needs to remain street friendly.

[tryingbe]

The picture in that thread is dead. Any way to revive that image?

Three manifolds for T5. I don't remember the year exactly.

94-2000 crack(s) at the collector is usual.
01-04 (Japanese) casting seems cleaner, and usually no crack
05+ (R manifold) used by R and non R cars, 2 lbs lighter, I believe, usually no crack.

https://www.matthewsvolvosite.com/forums ... hp?t=55616

Just look in there.


Soon...