|
|
|
|
Thread Tools | Display Modes |
06-07-2020, 02:26 PM | #451 | ||
NASIOC Vendor
Member#: 198281
Join Date: Dec 2008
Chapter/Region:
MAIC
Location: Virginia
Vehicle:2005 WRX/STi WRB of course |
Quote:
The further you go in the direction of inefficient design, the more difficult it will be to match those peak numbers, and the more disparity there will be in the rest of the power curve. Quote:
A crappy header design doesn't 'limit power' it limits performance. There's a difference. You can get a barn door to fly if you put a big enough rocket on it, but that doesn't mean it will fly well Turbines are ALWAYS most efficient when exhaust pulses are delivered with consistent energy from each exhaust event. Just like the bend plots above going from 0-90 shows ideal flow-to-poor flow, as you deviate exhaust pulses from perfectly spaced, turbine performance deteriorates. Not even getting into how UEL has a negative effect on the engine's Volumetric Efficiency: Cylinder Scavenging, Intake Charge Fill, AFRs, EGTs, etc., etc...
* Registered users of the site do not see these ads.
|
||
06-07-2020, 04:22 PM | #452 |
Scooby Newbie
Member#: 432734
Join Date: Oct 2015
Chapter/Region:
South East
Location: Savannah, GA
Vehicle:2016 WRX Premium Crystal White Pearl |
"But you're still not getting the big picture..." - NighthawkSTI probably
|
06-07-2020, 08:20 PM | #453 | |||
Scooby Newbie
Member#: 495630
Join Date: Dec 2018
|
Quote:
Quote:
Quote:
|
|||
06-07-2020, 08:49 PM | #454 |
Scooby Guru
Member#: 50586
Join Date: Dec 2003
Chapter/Region:
BAIC
Location: Chiraq
Vehicle:64 Impala |
Nighthawk really getting that post count up in here lol
|
06-07-2020, 08:53 PM | #455 |
Scooby Specialist
Member#: 504432
Join Date: Jul 2019
Chapter/Region:
Tri-State
|
Full of sound and fury, signifying nothing.
|
06-08-2020, 08:12 AM | #456 | |
Scooby Guru
Member#: 428511
Join Date: Aug 2015
Location: philadelphia
Vehicle:2016 STI |
Quote:
scroll back and re-read the 47 posts where this is simply stated. You really need KillerB to repeat for the 48th time what a twin scroll does and how headers are designed to optimize it? |
|
06-08-2020, 09:55 AM | #457 | ||
Scooby Specialist
Member#: 498642
Join Date: Mar 2019
Chapter/Region:
Tri-State
Location: our wrx IS the family sedan
Vehicle:'19 WRX Ltd 6M dgm '08 Mustang GT (the toy) |
Quote:
There's just something jarring and rackety about that sound that is at odds with any notion of smoothly-running machinery. Quote:
You say you hear "ping ping ping ping" from a VW - well, so do I. Are you saying you can't pick up a deeper-toned version of that same sound (let's describe it as being something like pung pung pung pung) coming from your Subie? It still beats me why you care so much about what the FA WRX sounds like when you already have the WRX sub-model that has the right sound for you. I know if I had an STi and liked its rumble I wouldn't have gotten involved in this discussion in the first place. Probably wouldn't have even opened up this section's list of topics. Then again, I suck at fishing, and going out in a boat on somebody else's pond and throwing a baited line over the stern would be a waste of too much time . . . Norm Last edited by Norm Peterson; 06-08-2020 at 10:06 AM. |
||
06-08-2020, 11:23 AM | #458 | |
Scooby Newbie
Member#: 495630
Join Date: Dec 2018
|
Quote:
you re-invent ways to say how much you hate the UELH Subaru boxer sound in every post LOL. The LEGENDARY Subaru signature sound of the UELH on their boxer engines will always get more attention than the raspy high pitched ELH...that are only relatively more efficient. I'd say CONSERVATIVELY that the UELH sound is more bad ass over the exhaust leak sound of ELH by 5-1....and again I think that is a fair but conservative estimate. You cant stand the boxer UELH sound, more than I have ever seen anyone hate anything LOL. You hate the UELH sound so much that you will compare it to an Air cooled V.W which is basically an lawnmower engine....and then go on in a hate fueled UELH rant to say that the STI is a "sub model" to the WRX LMAO. Hasn't been since 2015 separated them. The STI is the flagship performance car of the Subaru line up. Your a funny guy. |
|
06-08-2020, 11:29 AM | #459 |
Scooby Newbie
Member#: 495630
Join Date: Dec 2018
|
Its no where near close.....in that RPM range you referenced there are stock LS1's that record 80-100 Ft lbs more torque than a stock FA2.0 turbo Subaru.
|
06-08-2020, 11:37 AM | #460 | |
Scooby Specialist
Member#: 170780
Join Date: Feb 2008
Chapter/Region:
SCIC
Location: Orange County
Vehicle:2018 Type RA #350 2021 Honda Civic Type R |
Quote:
Sound, 100% aside, it's been stated and or proven that the UELH is an inferior design to the ELH header. No one thinks your motor will give up because you changed to a UELH, but it's going to have to work harder and ultimately give you less. If a tuned, well modified, WRX ultimately lost power and ended up with more lag - that's obviously not ideal. You can make power on a UELH header, when it's designed to run it like the STi is - granted we know an ELH will make more power. There's no real "hate", it's the mentality of modifying a vehicle to produce less power, more lag and ultimately leaves the "gains" to "sound" that are being questioned. If you want to praise the UELH, go for it, just know the ELH will probably make more power on a Subaru platform. |
|
06-08-2020, 12:05 PM | #461 | |
Scooby Newbie
Member#: 402552
Join Date: Sep 2014
Location: Canada
Vehicle:2016 WRX |
Quote:
Let's be clear, I have never once even considered getting these unequal length headers. It makes no sense to me, I appreciate the advantages of equal length headers and it would be silly to change that. BUT, I do like learning new things about engines, so I am interested to learn about the affects of using an unequal length header on a twin scroll turbo. I haven't been able to find much on this specific subject, so if you know a link with some good reading feel free to share it. ........Can anyone tell me why people come to a car forum to talk about cars and then get annoyed with people when we talk about cars too much? Isn't this the point of forums? I understand the anger over mis-information, but if you are tired of reading about headers, maybe stop clicking on this thread. Last edited by Comikazi; 06-08-2020 at 12:14 PM. |
|
06-08-2020, 12:15 PM | #462 | |
Scooby Guru
Member#: 428511
Join Date: Aug 2015
Location: philadelphia
Vehicle:2016 STI |
Quote:
Twin scroll: 2 hot side impellars, headers oriented for pulses arriving exactly 25% of cycle time apart to alternating ports. Results: Faster spool Take away equal length. . .reduced spool due to less than perfectly even pulse spacing. That's it, seriously, there's nothing more to it. People talking about scavenging are making statements out of context. The length just changes the optimal scavenge RPM, not the scavenging in general, so yes, each cylinder has a different ideal rpm. splitting hairs at this point. Nobody is annoyed about talking about cars too much, but let's be honest, this thread is 500 posts and counting and Nighthawk and Norm have honestly argued the same points 30 times in a row now. I'm almost sure they aren't going to agree at this point. |
|
06-08-2020, 03:22 PM | #463 | |
NASIOC Vendor
Member#: 198281
Join Date: Dec 2008
Chapter/Region:
MAIC
Location: Virginia
Vehicle:2005 WRX/STi WRB of course |
Quote:
There are two primary locations scavenging happens. In the primary; determining factors include length and diameter. If you have a small diameter 2" primary, your primary's scavenging capability will be terrible as the exhaust gasses have nowhere to go. If it's too long, there is no scavenging effect that is times correctly for the next exhaust event. Somewhere in the middle is where magic happens. The other area that can produce a beneficial scavenging effect is the merge collector. This is where the passing of one or more exhaust pulses can improve scavenge from other primaries. In a symmetrical order and maximum separation produces ideal results. Secondary size, collector design, and other factors play a role here too. |
|
06-08-2020, 03:33 PM | #464 |
Scooby Specialist
Member#: 448622
Join Date: Jun 2016
Location: Vancouver, BC
Vehicle:2019 STI SportTech CWP |
Sigh. He hasn't provided 'actual facts and proof'. He didn't give false statements either.
At this point i think it's all mostly a matter of semantics (in terms of what is fact and what is theory), so I personally won't really bother. Carry on... Last edited by F1EA; 06-08-2020 at 04:47 PM. |
06-08-2020, 04:09 PM | #465 | |
Scooby Specialist
Member#: 448622
Join Date: Jun 2016
Location: Vancouver, BC
Vehicle:2019 STI SportTech CWP |
Quote:
But the actual loss coeff also depends on the type of bend... short radius vs long radius... Also depends on the temperatures, the pipe diameter, etc. A aftermarket pipe will change all 3. So gotta look at it as a whole system. Either full calibrated CFD models of the 2 systems or... a simple hp/toque comparison of the stock header and the aftermarkt UEL (same car, same dyno, same day) if one only cares about the end result. |
|
06-08-2020, 04:09 PM | #466 | |
Scooby Guru
Member#: 428511
Join Date: Aug 2015
Location: philadelphia
Vehicle:2016 STI |
Quote:
Seriously? 2" primary is too small for 1/2 liter cylinder? Ever heard of a 572 big block? What do you think they have on them? Three inch primaries? You couldn't even physically fit that in place. I don't even have 2" primaries on my 6.2 liter supercharged V8. Underlined. . . .totally false If it's "too long" then it will be timed for a lower rpm. So when you say "too long" you mean it won't be timed for "x" rpm. Ok fine, so what rpm do you want it timed for? Because whatever you pick you will get, and every other rpm won't be timed right. So like I said, if you have unequal lengths then each cylinder will be timed differently, making the net result generally ok, but it won't be dead nuts optimized for say. . . .low rpm peak torque. So again, the 'scavenging' references are all out of context because they are stated kind of like you just did where you imply scavenging disappears with UEL when it does not, it just doesn't happen at the same time for each cylinder. |
|
06-08-2020, 04:58 PM | #467 | ||
Scooby Newbie
Member#: 495630
Join Date: Dec 2018
|
Quote:
Quote:
Lets see actual engine stand dynos of an FA with both headers back to back with pressure readings at the points of flow in the pipes..being discussed here. That would answer a lot of debate....at least on the flow end. A 2 horsepower difference is negligible in actual application....torque shifts can be compensated for by modulating RPM and shift points with a 6 speed manual. if an automatic/CVT were the only transmission available for the FA2.0 the torque curve shifts would be more critical for drivability and response. Clearly this is a discussion that needs much more data way too many variables to say that just because the "sound" of an UELH reveals stacked pulses that it will limit power potential on a FA 2.0 turbo. I really dont see why it would...the pulses are still entering a twin scroll turbo from relatively short distances from the exhaust ports in either scenario, and UELH have supported HUGE horsepower and torque outputs on Subaru boxer engines. Its an air pump..more air and fuel that goes in with mods will be happier with an aftermarket performance header that removes restrictions in the stock castings whether uel or el to the collector/turbo...UELH have proven to give enough margin if flow capability that they are overkill on a lot of builds, as well as aftermarket EL headers. If either supports the output that the builder sets as a goal that's all that matters. |
||
06-08-2020, 06:16 PM | #468 |
Scooby Newbie
Member#: 504042
Join Date: Jul 2019
Chapter/Region:
SCIC
Location: SOCAL - Sothern Cali
Vehicle:2018 WRX ISM |
It would be funny if the new 2021 STI come stock with an ELH.
|
06-08-2020, 07:59 PM | #469 | |
NASIOC Vendor
Member#: 198281
Join Date: Dec 2008
Chapter/Region:
MAIC
Location: Virginia
Vehicle:2005 WRX/STi WRB of course |
Quote:
If you have a small diameter, 2" LONG primary... I was giving example extremes to make the point... which I obviously did not do a good job of, lol Last edited by KillerBMotorsport; 06-08-2020 at 08:10 PM. |
|
06-08-2020, 08:09 PM | #470 |
NASIOC Vendor
Member#: 198281
Join Date: Dec 2008
Chapter/Region:
MAIC
Location: Virginia
Vehicle:2005 WRX/STi WRB of course |
Its truly interesting how some of you are trying to minimize the role of proven design principles because it's not speaking directly to THESE headers; like they are exempt from the rules of physics somehow.
|
06-08-2020, 08:18 PM | #471 | |
Scooby Newbie
Member#: 495630
Join Date: Dec 2018
|
Quote:
We need an actual measured test on THIS engine to put this to rest. |
|
06-08-2020, 08:28 PM | #472 | |
Scooby Newbie
Member#: 495630
Join Date: Dec 2018
|
Quote:
The extreme example of the physics involved simply doesnt translate to this application from what I have seen so far....the physics reveal a relatively less efficient scavenging but that's about it. Last edited by NighthawkSTI; 06-08-2020 at 08:36 PM. |
|
06-08-2020, 08:38 PM | #473 | |
Scooby Guru
Member#: 50586
Join Date: Dec 2003
Chapter/Region:
BAIC
Location: Chiraq
Vehicle:64 Impala |
Quote:
|
|
06-08-2020, 08:47 PM | #474 | |
NASIOC Vendor
Member#: 198281
Join Date: Dec 2008
Chapter/Region:
MAIC
Location: Virginia
Vehicle:2005 WRX/STi WRB of course |
Quote:
Please don't say there just one plot and log. Not that a source can't be reputable, but validating results means they are proven to be repeatable. |
|
06-08-2020, 09:45 PM | #475 | |
Scooby Newbie
Member#: 495630
Join Date: Dec 2018
|
Quote:
|
|
Thread Tools | |
Display Modes | |
|
|