I have read that once the engine is stopped the remaining oil in the turbo will cook and reduce turbo life..

I currently have an IHI VH22 turbo which is in the same family which comes on the Suburu WRX. This makes purchasing the coolant adapters/lines somewhat easy to obtain. Problem is, how do you integrate it into the 14's cooling system? and could it exasperate and engine which already runs somewhat hot? I have the 2 fans with auto and switch control and run engine ice.

Just wondering if running coolant to the turbo could extend the life and maybe reduce EGT's?

Thanks,
rick

sorry for the duplication....

Anyone? I have this question on turbo coolant. I had question about max oil pressure.... nothing but crickets. Guess I'll just figure it out my own.

This forum used to be very useful, but it's gone way downhill. Seems like all the turbo experts have moved on.

Last post for me, take care guys.

Soooo I'm no expert and never played one on TV however I have both a turbo 14 and Busa. That being said I've looked at and used the expertise of whom I consider experts. Richard Peppler, Rick Romans and Scott Davis in no particular order. I've not seen them incorporate coolant lines to any of their builds. I think the oil coking issues were prevalent when turbos were running on bronze bushings before they incorporated roller bearings. I see it as added weight and sources for leaks. I do run the liquid to air intercooler on the 14 to cool the air charge and earlier on they used water injection which can still be used though again you're adding weight and also have to keep the tank full.

I don't know if activity here will be like the early days ever again. It's the old days now and has been for some years. I encourage everyone to stick with the group. If you need to look outside of the forum for info, please report it back here. Hell, I even have asked ZX-14 questions on Hayabusa.org and come back to report! If Kaw makes a ZX-15, there will be a revival here.

Good answer Fordtech.

I have had three turbo vehicles and have never ran the coolant lines on any of them, bikes or cars, and have never had any oil cooking issues. As long as you let it idle for a bit after a long pull in boost you wont have to worry about oil cooking in the housing. Its one reason I prefer a slightly larger turbo than the common 47mm GT28s though - I dont want to ALWAYS be in boost, and with a larger turbo you can cruise around normal at low partial throttle positions and still be in vacuum and get roughly factory MPGs and less strain on everything. We dont really need the turbo down low anyway, 14s make plenty of TQ :). *edit, wrong forum LOL

* Last updated by: Puck on 1/27/2026 @ 6:21 PM *

Motorcycles have the benefit of air cooling on pretty much every part in addition to oil or coolant regulating temperature. The turbo sits in the front of the bike and will always get cooled once you start moving.

The term you're thinking of is 'coking'. When the oil gets boiled in the turbo and gums up the bearings/feed/drain lines. I wouldn't worry too much about that on these bikes. Adding antifreeze cooling to the turbo will just complicate things.

In theory it could help with life, but I doubt it would be a measurable amount. I don't think I've heard a story of someone's turbo going out from normal use and proper librication. Usually if the turbo dies, it's from the old electrical scavenging pumps failing. RCC offers mechanical scavenging pumps that eliminate that threat. Just change your oil often.

I have a diesel that's all upgraded and whatnot. EGTs probably reach 1400F every time I take it out, it just has a little oil line going into it. Stock turbo lasted 173k miles. You're overthinking it. And if you want peace of mind, just make sure you idle the bike for about a minute or two when you're parking before you turn it off. That will let the turbo cool off and prevent coking.

Thanks Guys.. that’s the info I was looking for… I am running an IHI VF22 turbo, same family as what the Subaru WRX runs. So, I have been reading their forums and info says coolant is a must. But, I do understand the turbo on the 14 receives some clean air when in motion. It wud be interesting to read EGT’s with coolant and without to see the delta.

Just reiterating that I am no expert. Especially with Surabrus. I do my best to stay far away from those things. I already have an unhealthy relationship with Audi's that I am not interested in expanding. I know a lot of subi guys. I actually happen to know the builder/owner of the fastest EK in the world, unless that record has been beaten. Just the number of engines it took to get there keeps me away. LOL

Here is something you can try- The easiest way to run coolant through the turbo is to delete the oil cooler with a delete plate. This leaves you with an unused bottom right nipple on the radiator and an unused nipple on the thermostat outlet. These are designed to cool the oil, but could be used to cool the turbo. You are not able to run an oil filter relocation kit or a low-pan with this strategy however.

* Last updated by: danmin on 1/27/2026 @ 3:21 PM *

Late to the party but I missed the "Subaru" part and FWIW I am running a subaru turbo as well, an upgraded TD05, and its been fine so far with ~6k miles and no coolant lines connected. I know thats not a ton of miles buts a true daily so it sees traffic and all weather and hasn't had any heat issues.

From what I gather, journal bearing turbos are more resistant to running with no coolant lines since they have huge tolerances for oil to fill for the shaft to float on, so are less likely to have issues from coking when you shut down too quickly after a pull. Bearing turbos are more sensitive to the burnt oil debris clogging them and causing the bearings to skid, and its recommended to keep the coolant lines for them.

I am now looking at the new breed of oil-less grease fitting turbos so I can delete the scavenge pump and oil lines for a cleaner install (and theoretically a little more power since I have the mechanical setup), but the smallest available are GTX30 sized which is a hair bigger than even my upgraded TD05 so spool would suffer (its a ~550hp turbo vs 450). On3 makes one that only needs coolant lines and no oil lines for $1200, and Comps are fully air cooled so no oil OR coolant lines which is awesome but they are like $1700 for a similar, but again slightly larger version.

The special high temp/waterproof grease tubes for them are ~$130-$175 but they supposedly last ~25-30k miles with the recommended 3k refill frequency so thats not bad at all, even a frequently ridden daily would get ~two years out of a $130 tube of grease.

Just debating whether I should try it now, or if I should wait for a rebuild when I up the displacement to counter act the later spool and can actually make use of it. Would kind of be a waste since I'm far from maxing out my current turbo, so it would mostly be an upgrade for convenience and to clean up the oil lines and stuff and would require a new header or at least a new flange welded on.