Where Has My Spool Sound Gone?

[CRSKmD]

SO over the weekend me and a mate upgraded the turbo on my RB20 to either an RB25 neo turbo or a VG30 (unsure what i ended up with. says OP6 on the rear housing)

anyway...

we replaced the turbo with the above

the stock front pipe with a 3" one

and the decat with a catco highflow cat.

drives fine, only running R33 waste gate actuator pressure (5.5psi or whatever).

before changing the turbo over i had a decent spool/induction noise.

now it sounds like a stock MK5 golf turbo. very quiet, high pitch whine. so what happened?

[GTSBoy]

No shaft speed = no spool up sound. The old RB20 turbo was running 10 psi and so was spinning harder. That sound is the sound of sharp alloy edges beating the crap out of air. Bigger compressor turning slower = less beating.

Boost it up and tune it and you'll be back to where you started (sonically) and about 30rwkW happier. Don't do this unless you have a good fuel pump etc etc etc. Wouldn't want you to destroy it.

[MBS206]

It's hiding behind the lounge.

[CRSKmD]

Hmmm see I thought that might be the case.

But even when the guage reads say 2-3psi on the old turbo there was sound.

Guess it could just be down to the turbo having a different sound.

Will have to just wait till I get a tune. Not keen on just winding up the boost. All supporting mods are there fmic fuel pump etc. but yeah

Edited April 10, 2013 by CRSKmD

[White_33]

Removed the actuator off your R32 turbo and put it on the R33 turbo -> instant 10psi.

[CRSKmD]

Had r33 gate actuator on my rb20 turbo. With a manual boost controller.