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MY00 //// BRP 2.5RS coupe
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Discussion Starter · #1 · (Edited)
Alright guys, this is not about how to install it or a comparison.

Let me tell you guys what I think about it.

It does absolutely great and does what it is advertised to do on a street car.
It does an amazing job at seperating the air from the oil for street car use.

Street car use includes; you street racers, dyno users, and touge runners.


But if you plan to track the car, I have only one suggestion don't use it.

WHY???? you may ask, if it works so well on street cars.

Well first of all after each session at the track, I get HUGE amounts of blowby. By a lot, I mean if I shut off the car after a session to cool down then proceed start it back up right before next session starts, bellows of smoke with a blue tint (which mean burning oil) comes out for a while until it clears.

Before you say anything about a turbo car having blowby etc, I understand it will have blowby even stock on a turbo'd car on the track.

(keep in mind with the stock setup I did not get this much at all!)

Second of all the car's oil started to have lots of fuel mixing with the oil, it smelt straight like fuel.

The problem I believe is that the aos does not have enough capacity to separate all the vapors or the oil quick enough during constant high rpm and aggressive driving during track days with high cornering G's.


My car has nothing crazy done to the motor if anyone is wondering.

06 wrx ej255
Stock long block
Stock intake
sti tmic
vf39
aps hard inlet
pnp throttle body
pnp intake manifold
pnp tgv delete
3mm phenolic spacers
full tbe

I am running 18.5 psi for boost if anyone is wondering.


Let me know what you think, or if you have had similar events.

I am currently looking for more alternatives!
 

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99' Subaru Impreza 2.5 Rs
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3,712 Posts
Alright guys, this is not about how to install it or a comparison.

Let me tell you guys what I think about it.

It does absolutely great and does what it is advertised to do on a street car.
It does an amazing job at seperating the air from the oil for street car use.

Street car use includes you street racers, dyno users, and touge runners.


But if you plan to track the car, I have only one suggestion don't use it.

WHY???? you may ask if it does so great fro street cars.

Well first of all after each session at the track, I get HUGE amounts of blowby. By a lot, I mean if I shut off the car after a session to cool down then proceed start it back up right before next session starts, bellows of smoke with a blue tint (which mean burning oil) comes out for a while until it clears.

Before you say anything about a turbo car having blowby etc, I understand it will have blowby even stock on a turbo'd car on the track.

(keep in mind with the stock setup I did not get this much at all!)

Second of all the car's oil started to have lots of fuel mixing with the oil, it smelt straight like fuel.

The problem I believe is that the aos does not have enough capacity to separate all the vapors or the oil quick enough during constant high rpm and aggressive driving during track days with high cornering G's.


My car has nothing crazy done to the motor if anyone is wondering.

06 wrx ej255
Stock long block
Stock intake
sti tmic
vf39
aps hard inlet
pnp throttle body
pnp intake manifold
pnp tgv delete
3mm phenolic spacers
full tbe

I am running 18.5 psi for boost if anyone is wondering.


Let me know what you think, or if you have had similar events.

I am currently looking for more alternatives!
I'm running an 08 sti short block, 09' wrx heads, wieseco pistons, and a fp hta68 turbo. This set up has only been in my rebuilt for a month or so. Last weekend finished off my clutch on my first launch with the new set up and put in another clutch a couple days ago. Noticed a nice coating of oil in my intercooler. I was a little confused since this is one of the things it's supposed to prevent.

The worst part was this morning. After a little fun on the way home last night I got to my house and let it run to cool down for a couple min. This morning I went to start my car and with my exhaust facing towards the garage door that was open completley filled the garage with smoke. I literally thought I had an electrical fire. It ended up clearing up and I drove it to work. I'll keep an eye on it.
 

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MY00 //// BRP 2.5RS coupe
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3,369 Posts
Discussion Starter · #3 ·
Yea keep an eye on it especially with blocks if aftermarket pistons which naturally let by more blow-by then stock pistons!

I would hate to see my motor or anyone's motor go out because there is too much fuel in the oil or blow-by in the combustion chamber.
 

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99' Subaru Impreza 2.5 Rs
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Good news is it did it at lunch when I left but didn't do it when I left work at the end of the day or when I left for work this morning so I don't think it's an issue with the new turbo.
 

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'17 Impreza Sport, '15 OB 3.6R
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Edited the title a bit, for you. Correct spelling for GrimmSpeed and added the full AOS name in parentheses, for those who don't know.
 

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MY00 //// BRP 2.5RS coupe
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3,369 Posts
Discussion Starter · #6 ·
Good news is it did it at lunch when I left but didn't do it when I left work at the end of the day or when I left for work this morning so I don't think it's an issue with the new turbo.
That is good news.

It sure does work well for driving on the street!

Do you plan to go to the track anytime soon?




Edited the title a bit, for you. Correct spelling for GrimmSpeed and added the full AOS name in parentheses, for those who don't know.
Thank you sir!
 

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Yeah I have a couple trackdays coming up next year. Car is in the best shape it's been in for a while. By then I will be using a cosworth aos. If that does that from one spirited onramp I'd hate to see how bad that happens from a couple laps.
 

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MY00 //// BRP 2.5RS coupe
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Discussion Starter · #8 ·
Yeah I have a couple trackdays coming up next year. Car is in the best shape it's been in for a while. By then I will be using a cosworth aos. If that does that from one spirited onramp I'd hate to see how bad that happens from a couple laps.
I plan to run the crawford v2 as they fixed the sludge problem from oil cooling inside the aos.
 

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'06 LGT
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8,334 Posts
This has been a well known problem with the Grimmspeed units. The Crawford AOS' although much more expensive is a better product out there for those who are tracking there cars.
 

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MY00 //// BRP 2.5RS coupe
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Discussion Starter · #16 ·
I would see if you can find a unit that is a tad smaller or build your own.

Had a hell of a time fitting the crawford v2 aos
(still the lines are little awkward for my liking still)
 

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2000 White RS
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I talked to Cobb and they said the grimmspeed one is no good. There isn't a big enough chamber to get everything separated correctly. They said the grimmspeed is a knock off of a other companies product which also doesn't work so well. The recommendation was to get the Crawford performance AOS.
 

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MY00 //// BRP 2.5RS coupe
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Discussion Starter · #18 ·
I talked to Cobb and they said the grimmspeed one is no good. There isn't a big enough chamber to get everything separated correctly. They said the grimmspeed is a knock off of a other companies product which also doesn't work so well. The recommendation was to get the Crawford performance AOS.
Prova AOS I believe is the first one, but if the crawford one was a bit smaller it would be perfect
 

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2002 WRX WRB - STi
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I'll have to dig it up but some one on NASIOC did a technical review of grimspeed and Crawford and also changed the lines to see through one so he can clearly see what is going on. The conclusion is as the above stated, during high "g"s the grimspeed does not work at all. I use the Crawford and did not look back because of the review he did.
 
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