Turbo surge

[Shirohige]

So when I was driving my s13 about a half year ago I heard a lot of compression surge. I drove the car for about 3 weeks, and the previous owner drove it for about a year. (Note it is the stock t25 turbo)

This week I had time to pull out my exhaust manifold along with the turbo. What I noticed was that in my intercooler piping there was a bit of oil on the sides.

Both wheels on the turbo are fine. They don't scratch the insides of the turbo and don't have any tolerance.

Before I will put a bigger turbo on my redtop, I want to know where I should start investigating this shit. I don't want my new turbo to have a lot of surge too.

[AlexN]

get a bov problem solved

[Shirohige]

Alright, hope that will make sure my next turbo wont have any surge!

[SoundEfx]

If you're seeing oil, that could also mean that your seals were going bad and might not have anything to do with surge.

Why did you blame the oil only on the surge?

I ask because the oil could also be cause due to too much oil pressure.

[Shirohige]

Originally Posted by SoundEfx

If you're seeing oil, that could also mean that your seals were going bad and might not have anything to do with surge.

Why did you blame the oil only on the surge?

I ask because the oil could also be cause due to too much oil pressure.

Aha. I don't know if it would be the motor oil though. When I took of the bolts attached to the engine for the turbo lines, there was a lot of coolant coming out of the engine. i think it was about 1,5 liters. Think that might have to do something with it? I heard that if you take of the bolts from the turbo lines it should give a little amount of oil and coolant. The oil that came out was maybe a full tablespoon

[Croustibat]

Originally Posted by Shirohige

Alright, hope that will make sure my next turbo wont have any surge!

Blow off valves can prevent surge when changing gear, but it does not prevent surge happening when accelerating. This can only be prevented by ... sourcing the right turbo (or using an electric wastegate actuator and opening it a bit when spooling).

If you have a redtop, you should already have a recirc'ed BOV. I suggest you keep it. Atm. BOVs usually leak and this does not work well with MAF based ECUs.

Anyway surge on a stock T25 turbo is not going to kill it. If there is oil at in/ex, it just means the seals are on their way out, which is not surprising at all considering it must be 2 decades old.

If you have some money around, get an efr6758. It is just at the limit of surging at low revs, but it matches SR20s perfectly. It also has an integrated recirc. bov and vband flanges, so easier plumbing and no leaks. Be sure to ask medium or hard spring in that actuator though (hard spring = 15psi boost pressure)

If you don't have much money to throw, good old gt2871r ar .86 is a cheap, solid contender. In between the 2, you can get a gtx2867r too.

[Shirohige]

Originally Posted by Croustibat

Blow off valves can prevent surge when changing gear, but it does not prevent surge happening when accelerating. This can only be prevented by ... sourcing the right turbo (or using an electric wastegate actuator and opening it a bit when spooling).

If you have a redtop, you should already have a recirc'ed BOV. I suggest you keep it. Atm. BOVs usually leak and this does not work well with MAF based ECUs.

Anyway surge on a stock T25 turbo is not going to kill it. If there is oil at in/ex, it just means the seals are on their way out, which is not surprising at all considering it must be 2 decades old.

If you have some money around, get an efr6758. It is just at the limit of surging at low revs, but it matches SR20s perfectly. It also has an integrated recirc. bov and vband flanges, so easier plumbing and no leaks. Be sure to ask medium or hard spring in that actuator though (hard spring = 15psi boost pressure)

If you don't have much money to throw, good old gt2871r ar .86 is a cheap, solid contender. In between the 2, you can get a gtx2867r too.

Aha, thanks.

I was so wrong about the compression surge. It was the stutter that made the sound. I am fairly new to these type of cars so it was a afwul mistake of me to assume it was surge.

Took the exhaust manifold out about a week ago with the turbo and the turbo had no shaft play at all. It was completely fine. No scratching against the housing. Just a really stupid of me to think it was compression surge.