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Old 05-21-2013, 06:16 PM   #1
blehhh
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Default Will an ELH increase strain on turbo & engine?

So, I know running 20psi on a stock motor & stock VF52 is not exactly a recipe for reliability as it is, but my tune is running very well, and I'm now considering an ELH for the added low-end torque & lower spool rpm.

My question is whether or not an ELH would make my engine & turbo even more likely to blow? (Similar to how running a turbo swap on a stock motor is almost an eventual guarantee)

It's hard to figure out, intuitively, because it would be increasing torque, it would make the turbo spool very low (making it nearly impossible to stay out boost when the car is cold) and it might flow too much for the IWG, (meaning I'd be inclined to port the turbo).

On the other hand, it smooths out the exhaust pulses, so there's less impact on the blades of the turbo, and maybe the lower restriction actually means less stress on the engine, even though the torque increases?

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Last edited by blehhh; 05-22-2013 at 08:22 AM.
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Old 05-21-2013, 09:13 PM   #2
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no
it's better off because of flow linearity and a lack of unequal pressures at each valve
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Old 05-21-2013, 09:20 PM   #3
blehhh
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Originally Posted by eg33GC View Post
no
it's better off because of flow linearity and a lack of unequal pressures at each valve
Ah, so it makes a difference at both ends of the system.

And the increased torque @ given RPM is had without the cost of added stress though, because it's merely a function of lower rpm spool, not altered exhaust manifold pressures or anything like that like.

I basically just don't want to get greedy and start asking too much of the stock motor, (like a turbo swap).
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Old 05-22-2013, 07:28 AM   #4
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Originally Posted by blehhh View Post
Relevant Mods:

Torqued Performance Stage III @ 20psi, 91oct
Did you talk to Eric about this already?
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Old 05-22-2013, 07:42 AM   #5
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It should only benefit your engine if tuned correctly. The current UEL header on your car causes exhaust temps to be higher in runners 4 and 2 because they are longer than 1 and 3...guess which 2 piston ringlands are the most commonly cracked (4 and 2).

An EL header will ideally result in lower EGTs for those 2 runners.
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Old 05-22-2013, 07:50 AM   #6
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Did you talk to Eric about this already?
Not yet, just dawned on me that I could do a header relatively easily and see big gains. I'd likely have Eric re-tune it, or I'd get a pro-tune and throw in injectors as well.
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Old 05-22-2013, 09:39 AM   #7
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Originally Posted by blehhh View Post
Not yet, just dawned on me that I could do a header relatively easily and see big gains. I'd likely have Eric re-tune it, or I'd get a pro-tune and throw in injectors as well.
Ask him about it, and if you're going to do injectors he'll do it if you have a wideband that you can hook up to ATR and log with.
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Old 05-22-2013, 10:25 AM   #8
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The current UEL header on your car causes exhaust temps to be higher in runners 4 and 2 because they are longer than 1 and 3.
An EL header doesn't shorten the 2 and 4 runners, it lengthens the 1 and 3 runners to be just as long as 2 and 4. So your argument doesn't make a lot of sense. By that logic, you should be saying that an UEL header makes 1 and 3 safer than an EL by shortening their runners.

OP - it's all about flow linearity, not EGTs or anything else. And people make all the fuss in the world about the horrid atrocities of UEL, but at the end of the day, a similarly designed aftermarket EL and UEL have been shown to make basically the same amount of power on the dyno, both of which significantly higher than stock. So go with what you want and safely ignore the EL nazis.
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Old 05-22-2013, 10:28 AM   #9
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Originally Posted by the suicidal eggroll View Post
An ELH doesn't shorten the 2 and 4 runners, it lengthens the 1 and 3 runners to be just as long as 2 and 4. So your argument doesn't make a lot of sense. By that logic, you should be saying that an UEL header makes 1 and 3 safer than an ELH by shortening their runners.
I was thinking the same thing, but he could still be right about the temperatures dropping IF the equal length aids the flow of the entire system so much to the point that back pressure inside the 2 and 4 runners is reduced.

Quote:
Originally Posted by the suicidal eggroll View Post
OP - it's all about flow linearity, not EGTs or anything else. And people make all the fuss in the world about the horrid atrocities of UEL, but at the end of the day, a similarly designed aftermarket EL and UEL have been shown to make basically the same amount of power on the dyno, both of which significantly higher than stock. So go with what you want and safely ignore the EL nazis.
I always thought EL shifted the torque curve to the left by like 500rpm, (because of the lower spool)... Is that not necessarily true? Am I thinking of a twin scroll setup? I wish I could find more conclusive, direct dyno before/after comparisons of this.

This is also making me really want to go EL (even if this dude can't drive):


Last edited by blehhh; 05-22-2013 at 11:07 AM.
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Old 05-22-2013, 11:07 AM   #10
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I always thought EL shifted the torque curve to the left by like 500rpm, (because of the lower spool)... Is that not necessarily true? Am I thinking of a twin scroll setup?
You're probably thinking of a twin scroll setup. EL headers are praised for their top end power, not their spool. And tests show that their top end power isn't really much different than a well designed UEL anyway.

Quote:
Originally Posted by blehhh View Post
I wish I could find more conclusive, direct dyno before/after comparisons of this.
There was a big header shootout several years ago. It compared stock to Grimmspeed to multiple tubular EL and UEL. In the end, the Grimmspeed made about 10whp more than stock, and both EL and UEL made about 10whp more than Grimmspeed, with very similar spool and power curves as each other. Unfortunately the server hosting the images went down a while back, and I haven't seen anybody re-host them. I wouldn't mind hosting them if somebody had the original images, but that seems to be hard to find.
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Old 05-22-2013, 11:19 AM   #11
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Hmmm... maybe it's not worth it then.

Someone at the dyno day this weekend had a 2011 WRX, Cobb OTS Stg 2 93 oct map, Perrin ELH, Perrin TMIC, Perrin Pulley, etc. He put down 297whp.

My 2012 WRX, TP Stg 3 20psi 91 oct, PW TMIC, GS Pulley, etc put down 291whp, (I actually made more torque than him)

It must be my 20psi that even landed me anywhere near his numbers, but this torque curve is what really caught my eye, it was left of mine by a few hundred rpm.

Not trying to chase numbers or even another car, just intrigued about potential gains.

My carbon fiber driveshaft (whenever it shows up!) should be good for a couple-two-three whp on a dyno though lol.

Last edited by blehhh; 05-22-2013 at 11:27 AM.
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Old 05-22-2013, 11:27 AM   #12
the suicidal eggroll
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Keep in mind that my comments are referring to EL vs UEL, not aftermarket vs stock. There are still significant gains to be had (both top end power and often spool also) from an aftermarket header, but whether that aftermarket header is EL or UEL doesn't matter a whole heck of a lot.
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Old 05-22-2013, 11:34 AM   #13
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Originally Posted by blehhh View Post
Hmmm... maybe it's not worth it then.

Someone at the dyno day this weekend had a 2011 WRX, Cobb OTS Stg 2 93 oct map, Perrin ELH, Perrin TMIC, Perrin Pulley, etc. He put down 297whp.

My 2012 WRX, TP Stg 3 20psi 91 oct, PW TMIC, GS Pulley, etc put down 291whp, (I actually made more torque than him)

It must be my 20psi that even landed me anywhere near his numbers, but this torque curve is what really caught my eye, it was left of mine by a few hundred rpm.

Not trying to chase numbers or even another car, just intrigued about potential gains.

My carbon fiber driveshaft (whenever it shows up!) should be good for a couple-two-three whp on a dyno though lol.
So the car with the headers was running a Cobb OTS map?
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Old 05-22-2013, 11:35 AM   #14
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So the car with the headers was running a Cobb OTS map?
Maybe it was a perrin map? I was going off of hear-say from others.

I was still surprised to be so close in power with a stock header.
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Old 05-22-2013, 11:39 AM   #15
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Originally Posted by the suicidal eggroll View Post
You're probably thinking of a twin scroll setup. EL headers are praised for their top end power, not their spool. And tests show that their top end power isn't really much different than a well designed UEL anyway.


There was a big header shootout several years ago. It compared stock to Grimmspeed to multiple tubular EL and UEL. In the end, the Grimmspeed made about 10whp more than stock, and both EL and UEL made about 10whp more than Grimmspeed, with very similar spool and power curves as each other. Unfortunately the server hosting the images went down a while back, and I haven't seen anybody re-host them. I wouldn't mind hosting them if somebody had the original images, but that seems to be hard to find.
curious, were these cars making quite large numbers or more moderate numbers? I would imagine the difference would be progressive(progressively larger) and not linear as overall power increases, no?
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Old 05-22-2013, 11:46 AM   #16
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Maybe it was a perrin map? I was going off of hear-say from others.

I was still surprised to be so close in power with a stock header.
I doubt you'd see much for gains without a proper tune for them.
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Old 05-22-2013, 11:48 AM   #17
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curious, were these cars making quite large numbers or more moderate numbers? I would imagine the difference would be progressive(progressively larger) and not linear as overall power increases, no?
http://forums.nasioc.com/forums/show...8&postcount=18
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Old 05-22-2013, 11:56 AM   #18
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curious, were these cars making quite large numbers or more moderate numbers? I would imagine the difference would be progressive(progressively larger) and not linear as overall power increases, no?
I believe the car was making low 300s on the stock header.
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Old 05-22-2013, 11:59 AM   #19
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I doubt you'd see much for gains without a proper tune for them.
Sounds like I'd be into it for well over $1000 then for parts and a pro-tune. (Unless I had Eric retune somehow).

meh.... lol More $$$ than I thought for worthwhile gains.
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Old 05-22-2013, 12:00 PM   #20
the suicidal eggroll
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Good link, those are similar gains to what I remember the aftermarket UEL and EL headers making in the header shootout I was referring to above. I don't recall the midrange gains being that high, but the shootout was done on an older car without exhaust AVCS, which could have something to do with it.
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Old 05-22-2013, 12:04 PM   #21
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Good link, those are similar gains to what I remember the aftermarket UEL and EL headers making in the header shootout I was referring to above. I don't recall the midrange gains being that high, but the shootout was done on an older car without exhaust AVCS, which could have something to do with it.
Agree.

I'm going to do a before and after airboy and virtual dyno.

Before will be turboback, after will be ks tech intake, perrin el's and a 38mm ewg, and ID1000s. Car is a 2012 wrx.
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Old 05-22-2013, 12:21 PM   #22
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thanks, I've already jumped onto the ELH bandwagon though
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Old 05-22-2013, 12:42 PM   #23
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Originally Posted by the suicidal eggroll View Post

An EL header doesn't shorten the 2 and 4 runners, it lengthens the 1 and 3 runners to be just as long as 2 and 4. So your argument doesn't make a lot of sense. By that logic, you should be saying that an UEL header makes 1 and 3 safer than an EL by shortening their runners.

OP - it's all about flow linearity, not EGTs or anything else. And people make all the fuss in the world about the horrid atrocities of UEL, but at the end of the day, a similarly designed aftermarket EL and UEL have been shown to make basically the same amount of power on the dyno, both of which significantly higher than stock. So go with what you want and safely ignore the EL nazis.
I never stated that EL would shorten runners 2 and 4... I am well aware that an EL manifold lengthens 1 and 3.

My point was that the longer 2 and 4 runners cause the EGTs to be higher in cylinders 2 and 4.
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Old 05-22-2013, 12:45 PM   #24
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I never stated that EL would shorten runners 2 and 4... I am well aware that an EL manifold lengthens 1 and 3.

My point was that the longer 2 and 4 runners cause the EGTs to be higher in cylinders 2 and 4.
Yes, relative to 1 & 3, but does the elongation of 1 & 3 actually reduce the temperatures in 2 & 4?
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Old 05-22-2013, 01:05 PM   #25
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Yes, relative to 1 & 3, but does the elongation of 1 & 3 actually reduce the temperatures in 2 & 4?
This is where I agree with Eggroll and the flow comes into play. If all runners are the same length, then the exhaust gasses would have the same distance to travel and result in even temperatures/flow.

Contrast the stock UEL manifold where you have relatively cooler gasses from 1 and 3 colliding with relatively hotter gasses from 2 and 4 at the up pipe. This back-up/restriction prevents gasses from 2 and 4 from flowing through freely (causing subaru burble) and causes Temps to be higher in cylinders 2 and 4.

This is what I have gathered from all my reading If there is any other information or evidence, please by all means share it. I don't pretend to know it all
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