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Discussion Starter #1
Has anyone removed your undertray? If so, why?

I know it would make it easier for oil changes, but are there other benefits - like less heat in the engine bay, or just negatives - like more dirt/debris in the engine compartment?

The reason I ask is because I was talking to AWDtuning about maybe installing ELH's, and they said I may lose the undertray.
 

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Mine doesn't fit because of ELH and my Killer B oil pan. I'm in talks with TBW about running their tray but haven't been able to get confirmation that it will fit. If it doesn't my buddy owns an aluminum shop and we will be making a custom one for my car this summer.
 

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Discussion Starter #3
Mine doesn't fit because of ELH and my Killer B oil pan. I'm in talks with TBW about running their tray but haven't been able to get confirmation that it will fit. If it doesn't my buddy owns an aluminum shop and we will be making a custom one for my car this summer.
Why do you feel like you need one - just want it, or some other reason?

BTW, how do you like the ELH? Do you think it's worth the price? Did you notice much of a difference performance-wise?
 

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Has anyone removed your undertray? If so, why?

I know it would make it easier for oil changes, but are there other benefits - like less heat in the engine bay, or just negatives - like more dirt/debris in the engine compartment?

The reason I ask is because I was talking to AWDtuning about maybe installing ELH's, and they said I may lose the undertray.
Removing the undertray would probably put more heat in the engine bay, or at least less air through the radiator. Temperatures under the hood don't matter as much as people think, the cars have fresh air intake and it's a liquid cooled engine to start with. All you really care about is the water and IC temp.

The air immediately under the bumper is a higher pressure zone and the undertray makes sure that the bay doesn't open up until further rearward so the air can draft through the bay and exit. Exposing the air underneath the tray to the engine bay adds turbulence to the airstream and slows it down, raising the pressure under the car and reducing airflow through the radiator and intercooler, while also adding drag.
 

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^ ^ ^ ^ ^

And the cars I have see without em have comparatively more rust at engine front - like our Bugeye.
My STI is wrapped ELH with no issue whatsoever.
 
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Discussion Starter #7
Ok, so keeping the undertray in place is a no-brainer.

Now, what about the ELH? For some reason my gut wants me to go for it, but I've had two nationally known tuning shops tell me the gains are not worth the price if you're under 600 AWHP. :confused:
 

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Ok, so keeping the undertray in place is a no-brainer.

Now, what about the ELH? For some reason my gut wants me to go for it, but I've had two nationally known tuning shops tell me the gains are not worth the price if you're under 600 AWHP. :confused:
ELH is also very beneficial if you decide to upgrade to a twinscroll turbo. aka the wrx engine
 

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I'm going with an ELH on my 2016 (with several other parts, finally only a couple weeks away!) for the safety/reliability benefits it provides.
 

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Ok, so keeping the undertray in place is a no-brainer.

Now, what about the ELH? For some reason my gut wants me to go for it, but I've had two nationally known tuning shops tell me the gains are not worth the price if you're under 600 AWHP. :confused:
ELH should improve the VE of the engine a bit and normalize cylinder temps somewhat which can make a little more power on any build for a given boost pressure and help turbo spool speed a bit but it does add a bit of weight and piping to the car and you lose the UEL sound obviously, so if you like that don't do it.

I'd consider doing one with a downpipe if I go the modding route but it comes down to personal preference.
 

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Why do you feel like you need one - just want it, or some other reason?

BTW, how do you like the ELH? Do you think it's worth the price? Did you notice much of a difference performance-wise?
Car was designed to run one, keeps the air flow how it's designed to be and provides protection.

For the headers, they are always worth it, but I did mine with a full build this winter so I don't have any UEL to EL direct comparison to make.
 

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ELH should improve the VE of the engine a bit and normalize cylinder temps somewhat which can make a little more power on any build for a given boost pressure and help turbo spool speed a bit but it does add a bit of weight and piping to the car and you lose the UEL sound obviously, so if you like that don't do it.

I'd consider doing one with a downpipe if I go the modding route but it comes down to personal preference.
I agree with everything said here except the ELH adding weight. I saved 12 lbs. compared to the stock ones when I switched. The stock headers are cast and have a lot of heat shielding which makes them heavier.

And keep the undertray on your car, it affects underhood airflow as well as aero slightly. Here's some good reading on the subject if you're interested:
AutoSpeed - Undertrays, Spoilers & Bonnet Vents, Part 1
AutoSpeed - Undertrays, Spoiler & Bonnet Vents, Part 2
AutoSpeed - Undertrays, Spoiler & Bonnet Vents, Part 3
 

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Discussion Starter #13
I agree with everything said here except the ELH adding weight. I saved 12 lbs. compared to the stock ones when I switched. The stock headers are cast and have a lot of heat shielding which makes them heavier.

And keep the undertray on your car, it affects underhood airflow as well as aero slightly. Here's some good reading on the subject if you're interested:
AutoSpeed - Undertrays, Spoilers & Bonnet Vents, Part 1
AutoSpeed - Undertrays, Spoiler & Bonnet Vents, Part 2
AutoSpeed - Undertrays, Spoiler & Bonnet Vents, Part 3
I was scratching my head as well when he said the ELH were heavier than the factory.
 

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I was scratching my head as well when he said the ELH were heavier than the factory.
There is a review I found on the interwebs about aftermarket headers IRT the benifits of EL vs UEL, IRC the ELH were slightly heavier due to the extra length to achieve the equal lenght, both headers were the same brand.

The extra weight was minimal though, from the review it was determined that unless you are making some big power the difference wasn't worth the outlay.

There is alot more science (fluid dynamics) involved around header design than most people realize.

Exhaust manifold - Wikipedia

If anyone can supply information from the manufacturers of what their manifold is designed for IRT hp and rpm goals could they supply the link to the information.

I always find it funny when people remove undertrays, the science is simple.
 

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Ok, so keeping the undertray in place is a no-brainer.

Now, what about the ELH? For some reason my gut wants me to go for it, but I've had two nationally known tuning shops tell me the gains are not worth the price if you're under 600 AWHP. :confused:
Killer B headers are magical, i only hear good things about them
 

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There is a review I found on the interwebs about aftermarket headers IRT the benifits of EL vs UEL, IRC the ELH were slightly heavier due to the extra length to achieve the equal lenght, both headers were the same brand.
Pretty much it right here. You can't do ELH on this car with less piping than you can do UELH. Beyond that it comes down to the construction of each header, they can use lighter tubes than factory but then you're also keeping less heat in the headers and they may not last as long.

The weight penalty if any certainly isn't high but it's not like new headers are all that cheap either (not that anything really is).
 

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Pretty much it right here. You can't do ELH on this car with less piping than you can do UELH. Beyond that it comes down to the construction of each header, they can use lighter tubes than factory but then you're also keeping less heat in the headers and they may not last as long.

The weight penalty if any certainly isn't high but it's not like new headers are all that cheap either (not that anything really is).
321 stainless is the boss, the only other material I would use would be steam pipe.

304 is cheap and easier to fabricate, it may crack, and will lose heat.

321 is stronger, can be thinner due to its strength, which makes it light and it retains heat better.

Steam pipe is cheap, heavyish, but strong and it retains heat well.

So far from my looking around I can get a KILLER B 321coated for around $2460au + delivery or a fabricated one using S355 steam pipe to my specs coated for around $2000au.

Lots of cash for minimal gains, a Blouch 1.5 + injectors may be money better spent.
 

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But you can buy "decent" cheaper ELHs that cost a fraction of of that, get you 90+% of the benefits and last a few years. When I need to re-wrap I'll just buy a new one & I'll still not be close to $2450. No one is likely to have the car past that as it would have close to 300k on it by then.

My point was 90+% of the benefits at a fraction of the cost might be worth it on higher performance builds. Having spent over $12k in parts for a build/rebuild, I still didn't end up with
em even though I wanted em at the time. There were so many more important parts.. After the fact I decided it was the right choice under the circumstances which was a significant but not cost not object budget.
 

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Discussion Starter #19
Is the factory up pipe a 2-bolt design? I'm asking because Killer B has a 2-bolt option, but I'm not sure if that means it works with my factory up pipe.

The reasons I'm not considering the more expensive option with their own up pipe is because my tuner says installing the up pipe adds considerable time to the install and there's not really much benefit other than looking prettier...and it's more expensive.
 
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