Thanks a lot for the review and the video. Just to be helpful about the design criteria, having too much flow is a bad thing for this kit. My fitting is custom and not off the shelf because I spent a lot of time testing different internal diameters. Too large of a diameter causes low heater core flow (even more than these kits already produce), reduced balance and flow to the other cylinders and the oil cooler. The hose is a very high temp and expensive silicone hose with a tighter allowable bend radius than other hose on the market. Made in the USA. The hose clamps are all very high grade stainless clamps. Made in the USA. The worm clamps are stainless, non-perforated, SS, embossed, rolled edge clamps. Made in the USA. The fitting is custom made, anodized, 6061 aluminum. Made in the USA. The T is Stainless, but made in Poland. (The VEMS T is just coated mild steel). The kit was made to create a good balance in the cooling system and the internal diameter is what dictates that. A Y would be too much flow as well. Lastly, at the very end, you showed the hose connected to the T incorrectly. On your setup, you should be cutting the hose down to the size shown on the instructions. Thanks again!

@SubaruONLY

4 жыл бұрын

Thanks for taking the time to add all this great detailed info Dom! And thanks for putting this kit together in the first place. Sounds like I missed a lot of great technical info when making this video, sorry about that. But overall, it’s clear to me your kit is far superior to anything else on the market! I also love that all your parts are manufacturers here in the US, nice job man. Maybe we do a SubaruONLY Podcast - You interested? Would give you a chance to walk through all these details and share any other cool things you are working on. Cheers buddy! 👊

@bradleehill9662

4 жыл бұрын

Your amazing dom one day I will make the trip to Washington to shake your hand

@GetaDomTune

4 жыл бұрын

@@bradleehill9662 look forward to it

@bdubblu

4 жыл бұрын

Getting Dom’s kit after C4 detonation flattened my rod main bearing. I’m surprised that the big shops don’t even mention this mod. I’d make it a serious note on all EJ builds... like as serious as the oil pickup.

@802Garage

4 жыл бұрын

Just want to say it's nice to see you give feedback without slinging any mud! Awesome info. :)

Support the guy who originally brought us the product (dom acia)

@bobbytwotone9429

4 жыл бұрын

All the jdm v8 ej207 have this bypass from factory so I think dom just copies it good idea tho wish I thought of it

@tflo9543

3 жыл бұрын

@@bobbytwotone9429 That's definitely not true. There is just a plug there like the usdm EJs. Same with the v9.

@SubaruONLY

3 жыл бұрын

Yea, think you are right. How about the twin turbo JDM Legacy models? I think those use this coolant route too.

@tflo9543

3 жыл бұрын

@@SubaruONLY I can't honestly say with the twin turbo 205, never seen one in person. As for the version 8-9 ej207s, I can definitely verify they are just like usdm.

@SubaruONLY

3 жыл бұрын

Got cha. Thanks!

First, Thanks for taking the time to make this and your other 75 videos. I have no idea why this is labeled reverse cooling, it doesn't reverse the cooling design at all. Most importantly though, too much flow through the back of the head negatively impacts cylinder 1. ie. Moves the problem. We optimized the orifice size on the dyno while testing coolant temps coming out of the back of each head to get them as equal as possible. We designed a custom fitting but found the specific Phenix fitting we use was within 0.010" of our optimal size and provided a delta of only 2 degrees F between the heads, so why complicate things, add increased lead time and increased cost? The only client of ours that had installed a GDT kit had to wire tie it away from the steering shaft. With the AN fitting you can route it away from the steering shaft upon installation. That's not apparent for you yet though since it's on an engine stand. Also, please dont use RTV on threads. If anything, use thread sealing compound, but that's not required when you use a crush washer.

@SubaruONLY

4 жыл бұрын

Guys - just saw this comment now (I guess it got pushed to potential spam folder. I approved it, as you’re seeing now, sorry for the delay). Ok - thank you for taking the time to clarify and add the background on the R&D that you guys performed. I owe you a follow-up review video to share this additional information on the VEMS kit! Your logic about moving the problem to cyl #1 makes a lot sense. And choosing to select the orifice size based on balancing the temps exiting the back of each head seems very logical too. One last question, using this kit effectively pulls the heat out of the #4 cyl head area and transfers it into the coolant, have you done much testing under more severe driving conditions like track days, to confirm that OEM Subaru cooling systems can keep up with the extra heat this puts into the coolant system? Do you think a larger, more efficient radiator is needed at some point? Thanks guys! Luke S.

@josesanchez4470

4 жыл бұрын

Soo ill say for a regular person that not a nascar driver vem seems to have the orifice size of coolant moving. For track days, Dom been slightly bigger is made to move more.

@sezwo5774

4 жыл бұрын

@@josesanchez4470 All of this information makes a case for installing a higher flow thermostat. MotorRad makes some of these for Subarus. Has anyone tried a high flow thermostat? Do they make a difference? Maybe it would be better to drill a few small holes to improve flow in an OEM part. Of course It would NOT selectively address or fix cylinder 4 problems just hopefully be a small improvement to flow (if the combined area of the diameters of internal passages, holes in the head gaskets, is not smaller than the thermostat opening and not the primary obstruction to faster flow in the system (?)). If I lived in Hawaii, southern Florida, southern Texas, or maybe San Diego I would be very tempted to delete the thermostat completely.

@SecretSauceyjuice

4 жыл бұрын

@@josesanchez4470 No. The larger diameter would only help if both cylinder banks had a larger diameter outlet hose from the engine back to the pump. You'll just burn up cyl1 with a big ass diameter tube on just the 2 & 4 side.

@802Garage

4 жыл бұрын

Just want to say it's nice to see you comment and only provide info with no negativity. Nice addition guys. :)

Never heard of this mod till now and it is absolutely genius. I think that will make a nice little weekend project

This was done by Subaru OEM in many JDM engines, the exact same result can be achieved for about $15 in hose and fittings. You can buy an OEM plug with a hose Barb that fits the rear of the cylinder head, and then you just need some hose and an Amazon T fitting (or even better, a Y fitting).

@SubaruONLY

3 жыл бұрын

good home hack for sure!

Was getting ready to do a timing belt on my wifes wrx soon. Thanks to you i will now be adding this to the job. Awesome! Thanks!

Excellent and very well put together review, cleared up a lot of questions i had. Thank you!

Very glad I found your channel, thanks for all the help!

so its a m20 but whats the tread pitch

I'm so thankful for this channel! You are an excellent teacher

@SubaruONLY

3 жыл бұрын

Thanks man - much appreciated!!! 😁😁😁

This is gold information... completly free!

@danspeed7039

4 жыл бұрын

It comes stock on some ej turbo engines

@STR00Z

3 жыл бұрын

@@danspeed7039 false

Just a note: in the test fit you installed the T fitting incorrectly.

@The2004STi

4 жыл бұрын

Noticed this as well, even though it's a mockup, I think it's important to be accurate. I also don't think a "y" fitting would work well either. I think it's made to not only let coolant enter the heater hose flow, but the coolant in the heater hose will inherently pull the cyl 4 coolant into the fluid stream... Having the straight part of the T fitting being the heater flow would allow that to happen whereas a Y fitting might allow some coolant flow from the heater to try to enter the cooling mod hose.

@The2004STi

4 жыл бұрын

Side note, are you T3h Clap from the write-up threads on Nasioc and IWSTI?

@josesanchez4470

4 жыл бұрын

That's when you know he works for dom

@SubaruONLY

4 жыл бұрын

Thanks and good catch.

@SubaruONLY

4 жыл бұрын

I don’t work for Dom. But I think the guy is a cool dude that I support 100% 😁😁😁

I have a non turbo 2011 Impreza 2.5i, and I drive full time for Uber and Lyft. I have the understanding that this is more geared towards modified turbo cars, but with the long hours my car is running is this something I should consider for my NA car as well?

Hey bud thanks for the comparison. Went with the VEMS kit for the reasons of the fitting not needing a gasket RTV that if serviced will need a full cleaning and reseal that you may not have time for, the hose doesn’t need to crimp even if it still keeping the ID of the hose correct bending the GDT kits hose it’s freaking silly but it gets me. I do think the GDT kit should have AN option for a tier price and both should use those non marring type hose clamps for the heater core hose you cut instead of the worm drive like a fuel hose clamp but Dom in his latest video stated that even the worm drive clamps are really hard to get never mind stainless quality ones. Just my two cents as I don’t have any degrees in engineering so hats off for figuring this mod out. I gave you a shout in my video as I went over the nuances of the VEMS kit with a rough install of the components on my 04 STi.

@SubaruONLY

3 жыл бұрын

All good points. Makes sense to me. Cheers!

I just picked up the RCM street cylinder 4 cooling mod for 33 bucks. Excellent quality for the price.

@SubaruONLY

2 жыл бұрын

Hell yea!!! Nice 👍

Awesome video mate thanks 👌👍

@SubaruONLY

3 жыл бұрын

😁👊

You mention to use grey RTV on the VEMS adapter with a crush washer. It should have an o-ring or bonded washer. The adapter is a male metric pipe to JIC, also called AN. The metric side is designed as an o-ring boss connection with metric threads. The thread is related to manufacturer and country of origin. Japanese and automotive tend to use more metric than imperial. The imperial US version is commonly known as UNO or ORB for o-ring boss in the US. There is a British pipe parallel (BSPP) thread o-ring boss which is commonly called British Port. British threads and US threads are imperial but are mostly not interchangeable. Each of these thread types have a different size seal interface between the adapter and the receiving port. The internal diameter of the adapter can be the same but a different thread interface will have a different o-ring size seal. The adapter is designed to seal with an o-ring at the base as it is compressed to the receiving port. Looking at the surface of the receiving port, you should be able to see a continuous chamfered edge. The adapter will have a non-threaded space next to the hex shoulder where the o-ring should sit. A second option is to use a bonded washer to seal between the adapter and the port. The use of an o-ring or bonded washer are not optional. Using sealant on the threads might work but the interface is not designed to seal at the threads. A national pipe thread fitting (NPT) and British Pipe (BSP) have a taper and threaded to the base or hex shoulder. The tapered threads mash into the female port to seal. Thread tape is a lubricant because the seal is made when deforming the threads and port to make a seal. It is a best practice to use an adapter and convert a NPT port to a different seal connection such as a JIC (joint industry council also called an AN or Army Navy), O-ring face, or other common connection. You'll notice it is difficult to clock a male NPT connection and O-ring Boss unless it is a female swivel with cone on a male nipple. British Pipe Parallel is designed this way with a swivel nut compressing a cone onto a male pipe nipple. Lastly, when designing a hose assembly, it is best to use a swivel connection and to have no more than one end angled. This means if the connection path requires two angles to complete the path then it is best to use angled adapters so the hose assembly will have straight hose tails. Next best would be a straight and an angled adapter with the hose assembly having a straight on one end and an angled fitting on the other. Based on design, I like the Vems except I would rather see a hose T with a JIC middle connection. Reason is the JIC male on the adapter to block and the JIC male on the T can be capped if the hose between fails.

Would you also suggest adding small hood risers to help cool the engine down even more? I have a 2017 Forester if you are wondering

Cool video (No pun). Subscribed.

So what if you're running an oil-cooled turbo and not using the water port near cylinder 3 anymore, would you repeat this mod for that side? Seems like you'd have the same issue with cylinder 3 once you close that coolant port...

Getting geared up to fix my 0 compression cyl #4 issue and will implement your fix... Much obliged!

Nice kits. I'm definitely going to do this mod, when I build a spare EJ207 for my V5 RA.

@danspeed7039

4 жыл бұрын

Brendon it comes stock on some subies. Tashs cars got it already done. Ill show ya bro

Just put the DOM kit on an 04 FXT build. Great quality and there is a visible drop in where the temp needle rides

@SubaruONLY

2 жыл бұрын

Awesome. Like to hear it. Cheers!!!

What size wrench is the nut on the 45 degree AN fitting? I wanna build my own kit but don’t want the pinch point of the straight hose. Thanks

Thanks but why isn’t this already done to the OEM set up on an STI?

I put this in the reply to T3h_Clap but... I also don't think a "y" fitting would work well either. I think it's made to not only let coolant enter the heater hose flow, but the coolant in the heater hose will inherently pull the cyl 4 coolant into the fluid stream... Having the straight part of the T fitting being the heater flow would allow that to happen whereas a Y fitting might allow some coolant flow from the heater to try to enter the cooling mod hose.

What happens if the cylinder 4 mod was connected to the silver line above the block and not the black line?

Anyone know what the typical thread size for that plug is?

Hey Luke thanks for the video. Also a hydrogeologist with Barr Engineering. I own a 2011 STI with an IAG stage 2 short block - I'm thinking I need to do this mod. I'll add you to LinkedIn!

Should this be installed on the new Subaru Assent model SUV

I ordered the vems kit. It was on back order,and the vendor offered me a substitute kit. I declined and waited for the vems kit to arrive. Glad I did after seeing the alternative kit.

So what ties on to the top of that T fitting?

What is the thread size of that 20mm piece?

Can you use this mod on ej2.5 soch?

Luke, got links to sourcing these kits or you got them in your amazon store?

Thank you sooo much!

@SubaruONLY

3 жыл бұрын

Glad it helped - cheers buddy!

Witch one is the one we should buy

Is this also for the Wrx? 2015 Wrx to be specific

Nice vid again. But i dont see egts results in cylinder temps at 400hp that show a concern. I dont track my car thou, just drag and daily. Reckon i will do this mod anyway but i will use the smaller outlet size just to promote a little better water flow at back of block.

@SubaruONLY

3 жыл бұрын

Prob better to be safe. Don't think it would hurt in any way.

I did this mod and my heater core blew only hot air. I also didnt have air conditioning so i put it back to stock

Can this be installed without removing the intercooler? I'd rather do the install from the bottom if possible. If you know, cool, if not, I'll have to try it myself.

@SubaruONLY

4 жыл бұрын

Hi. Yep, these can be installed from under the car. I think Dom (from get a Dom tune) has a video showing this too, fyi.

Many thanks for posting this vid (among all your others ! ) . Just found out about this mod the other day and was dumbfounded by the cost. Thank you for measuring the plug size ! Wanted to make my own but could not find the size anywhere ! Is it possible to have you verify the pitch of the thread as well ?

@dankcincy

2 жыл бұрын

If you you don't want to support the person who took the time to develop this and release the info to the public..... Just take your plug to the store with you and compare.

@owensharp8568

Жыл бұрын

@@dankcincy Where I live I'll probably pay twice the mod cost in shipping to get one here, so I'm taking my plug out and finding a fitting for myself at the local hardware :P

Luke thanks for explaining the reason why #4 is heating more than the other but is it really necessary for a stock engine to stall this? Will this affect the warranty. Subaru should have known this defect since the 90’s right.

@SubaruONLY

4 жыл бұрын

Great question buddy - And to be honest, I can’t say with certainly. Overall, if you are running 100% stock and not using your car for any extreme driving, just changing the fluids is the biggest thing you can do for reliability. Also, any time you add complexity (ie this kit), you open the door for unintended negative outcomes, however, that being said, if you install this kit correctly, it can only help and may end up having some real benefit over a couple hundred thousand miles. On that note, even stock motors that were never raced always need to have the heads surfaced when replacing the head gaskets around 150k mi. That means there’s most likely uneven heating and cooling across Subaru heads, which is what causes them to twist slightly over time. In theory, keeping your heads uniformly distributed with heating and cooling cycles would help them from tweaking over time and needing that resurface. So, overall I think this is a good mod for anyone - as long as it is installed correctly. Good luck and thanks for dropping the question. Cheers buddy! 😁

@kogiekobayashi3421

4 жыл бұрын

Thanks Luke, overall the benefit is greater than the negative outcome. Will install it before summer comes.

This guy was works with Dom..

$90.00 ? I assume that includes "installation" ;O) But really GR8T description of how it all works. Thank you. Thumbs Up!

The measurement tool you used @ 6:40, where can I buy that? -Thanks

@SubaruONLY

3 жыл бұрын

Got it from a small local hardware shop many years ago. Prob could find one on Amazon or eBay tho. 👍

Beatrush I believe is from Japan made by Laile.

This solved my anxiety for tomorrow....

@SubaruONLY

3 жыл бұрын

nice...

What do you connect the 3rd port of the "T" fitting to?

@SubaruONLY

4 жыл бұрын

Coolant line.

@SubaruOnly, thanks for thi educational material. Wondering if this will work on a Subaru Forester 2001 EJ20 engine. It has a Turbo sti kit. Also, i seem to be getting lots of heat on the engine to a point where the reservoir tank is full n boiling when i stop.. cn you guide me..?

@SubaruONLY

3 жыл бұрын

Yes, would help on any EJ style block for sure. Especially if overheating issues occurring. Also, verify it’s not a head gasket, that also causes overheating. Good luck! 👍

@JohnKatiku

3 жыл бұрын

@@SubaruONLY i will try and order one asap. I have checked my head gasket seems to be ok. Oil is clean and enough, changed radiator cap, but i seem to be getting lots of heat. Today the coolant was drained a fter a short drive of about 1.5hrs. given i took abit in traffic and was goiing uphill. CN you guide me on what would be the issue..? Am afraid to take along drive now. Afraid the engine might brick due to heat. Is this normal behavior with subaru engines..?

@SubaruONLY

3 жыл бұрын

No, not normal behavior. Something is definitely wrong if that’s occurring. Verify no coolant leaks anywhere too. Old water pump? Bad thermostat?

5/8” Wye fittings in stainless seem to not be common and the one I found is $45 and isn’t barbed. I’m guessing the idea of using one didn’t slip the companies minds, More like they didn’t have that option

Does this only effect the ej series engines or all Subaru 4 cylinder power plants

@GetaDomTune

4 жыл бұрын

EJ only

@DrRyan82994

4 жыл бұрын

What about ej253's

@GetaDomTune

4 жыл бұрын

Yeah

I see you measured the thread diameter as 20m but what is the thread pitch?

@SubaruONLY

3 жыл бұрын

1.75 I believe. Cheers! 👊

Has anyone seen a drop on #4 EGT temps with this kit?

@SubaruONLY

3 жыл бұрын

Great question. I haven’t been able to find any data. If you find any, please share! 👊

Video was biased from the beginning, Didn't even show the VEMS kit installed. The AN fitting provides a much better hose angle for flow and clearance. After reading the comment, below, from VEMS, I will be purchasing their kit.

@SubaruONLY

3 жыл бұрын

Fair enough. Hope the video still helped in some ways.

👍👍👍

Have you got the link for me to purchase gdt kits

@SubaruONLY

3 жыл бұрын

Yes, just checked with Dom, here’s his site: Shop.getadomtune.com

Pretty sure you've got this before. Your videos are awesome but the audio on your non cut scenes is wicked low. Keep uo the good work sir.

Get it Dom Kit looks like it will crease from the bend when installing which I don’t like

@bbbugeye2744

3 жыл бұрын

You have to trim the hose. Trimming it will allow it not to bend.

@SubaruONLY

3 жыл бұрын

Yes, exactly. I should have made that more clear!

Where can I buy this kit… I already have the outlet. Doing a ej20 swap

@SubaruONLY

Жыл бұрын

IAG should have some good options!!!

@ianmsevilla

Жыл бұрын

Oh, IAG… my brother got his tuff 2 block from them. 600 hp on his STi

@SubaruONLY

Жыл бұрын

Nice!!! That’ll be fun!!!

Can this be done in the car?

@vemstuning6540

4 жыл бұрын

Yes, we install them in the car every time. Though if the engine is out we put the fitting in the head before we put the engine in the car for convenience but leave the other side for finishing with the engine in the car.

What about cylinder number 3 , it get enough cooling?

@GetaDomTune

4 жыл бұрын

yes. Most flow to least flow: 2, 3, 1, 4. 1 and 3 are very very balanced with just the extra flow to 3 because it has to feed the turbo.

@moshelevy9785

4 жыл бұрын

@@GetaDomTune ok thanks I didn't find this mod on ebay, where can I get it?

@GetaDomTune

4 жыл бұрын

@@moshelevy9785 www.shop.getadomtune.com

@moshelevy9785

4 жыл бұрын

@@GetaDomTune cheers

any issues doing this mod on NA engines?

@SubaruONLY

7 ай бұрын

It can, but it really shouldn’t be needed.

Where can i buy this kit in Australia?

@SubaruONLY

3 жыл бұрын

Rally Sport Direct and IAG sell these kits, sure they ship to AU. Pick one up for sure! Cheers! 👊

Vems actually tested the flow to be equivalent to the odd pistons flows not too much not to little (Edit: I love your vids! I’d prefer the cheaper route anyway cuz a 90$ for a special fitting hose and three way isn’t my forte)

M20x1.50 right?

@GetaDomTune

4 жыл бұрын

yes.

You set up the T-fitting in the wrong orientation, used rtv where you shouldn't, and nitpicked the better quality kit for using sourced parts? That's a paddlin'.

Have a ea81 in a 83 gl wagon .hadnt seen any older vids ..come on now ...

Where does the T connect to after that? Lol

@kratic7696

4 жыл бұрын

The black pipe he mocked up is where you T into the coolant line.You place it like a T into that line, the bottom of the T goes into the new hose you just installed.

5:24 Sounds like GDT is paying you to say this lol

@SubaruONLY

3 жыл бұрын

ha. nope.

Thumbed it down because you did absolutely zero testing to confirm that you fixed a problem

@SubaruONLY

2 жыл бұрын

Fair enough. Respect that take.

Coolant reroute kits are available from other vendors for the Miata as well. My issue with these reroute kits is that they make claims of cooling the number 4 cylinder, but they don’t have any tests to support it. Yes the design in theory looks better, and for built performance race motors, sure go for it. I did the reroute on my built motor, but for the vast majority of Miata owners, this isn’t necessary. Do any of the Subaru vendors have any testing to show the benefits? I couldn’t find any.

@final3119

3 жыл бұрын

Both doms and vems have testing data on their websites.

MATE SOME EJ20T SUBARU COME 'STOCK' WITH THIS DONE!

@Mikey6048

4 жыл бұрын

Really? Whwre did you see this information?

@danspeed7039

4 жыл бұрын

@@Mikey6048 iv got 1 here. So its not 'information' the JDM 2004-2008 legacy with ej20y &ej20x has it stock.u can pick it up from scrap yard for 10bux Sorry to burst ur bubble

@mrsatangto

4 жыл бұрын

@@danspeed7039 Lets see a pic of it.

@dsxmotorsports

4 жыл бұрын

I run the oem one with out problems 🤷🏼‍♂️

My questions are Why is there a bung to begin with? A rather large one at that. And why hasn't Subaru figured this out?

@chrissheehan3033

4 жыл бұрын

The twin turbo legacy gt has twin turbos and used this port as a coolant return for the second turbo.

@dsxmotorsports

4 жыл бұрын

Subaru also used it to run through a water/oil trans cooler for the old 4eat. Pretty sure this was all jdm.

Neither of them kits are the best one. Torque solutions created the first kit and have the best kit on the market

85 dollars for a basic parts is just ridiculous, sorry, even with all the know-how

Neither kit is worth almost $100. I think you can make your own kit for less. I like the kit with the an fittings better.

@GetaDomTune

4 жыл бұрын

Neither of them costs 100.

@michaelhite1433

4 жыл бұрын

Dominic Acia still over priced for what it is, and I said almost a $100. Which price plus shipping is almost a $100.

@GetaDomTune

4 жыл бұрын

@@michaelhite1433 go have a custom designed 6061 fitting made and anodized, get a stainless steel 5/8 tee, high temp silicone hose, 4 304 stainless embossed clamps and come back with that price. I'll wait.

@michaelhite1433

4 жыл бұрын

Dominic Acia silicone hose is $5 a foot which I’m sure you get a deal on because you buy it in bulk, stainless clamps are a few bucks, a stainless tee $6 to maybe $15, which you also probably get in bulk, the fitting is the only unknown. Vems gets theirs from Phenix industries, which I’m sure they get a bulk price. Now of course you aren’t going to share how much you pay for this wonder fitting or where you get it.

@GetaDomTune

4 жыл бұрын

@@michaelhite1433 I have them machined by PYI. They are my design because the internal diameter is critical to proper operation of the cooling system. Going too large messes up all kinds of stuff.

they are both overpriced to a point which makes me angry!!