Does "Boost" affect "Spool"?

[Redlined]

Got my STI cat back installed. Looking for a catless downpipe to put in. but Ive noticed, even with just the cat-back, The turbo spools alot easier... 2500-2700 rpms at 1/4 throttle instead of 3000 RPMs at 1/3 throttle. Needless to say, the turbo spools up every damn time i accelerate the slightest bit, so i drive around sounding like a freight truck instead of a sport machine.

I find it annoying and it brings up questions of economy, parts wear, etc. Anyways. I don't like it. So I started thinking. Reducing back-pressure allows the turbo to spool quicker... what If I put on a manual boost controller and gave it a touch more boost? Seems to me, more boost requires more pressure to spool the Turbo, and therefore, would require more throttle/RPMs for the Turbo to spool.

Any input would be appritiated.

[evolutionmovement]

No. That would only give you more power by opening the wastegate later. The mass and geometry of the turbo don't change, so the exhaust gases spin it the same. What you could do is reduce boost - you'll still start to spool up at the same engine rpm, but maximum power would be lower, so less fuel use. You want some boost anyway for better efficiency as running low compression on its own is pretty inefficient.

[Adam West]

Isn't most of what you are hearing is the wastegate opening? Since upping the boost will keep the gate closed longer = less sound???

R. Dave, BTW, that is a GOOD sound that people pay major $$$$ to hear. <grin>

Cheers,
AW

[93forestpearl]

You don't really hear the wastegate at all. You hear the turbo's CHRA spinning at 100,000+ rpm. Plus some induction noise depending on your intake setup.





Get a big turbo. They don't spool up so easy.

[Adam West]

Ah yes, you really hear the boost actuator...

[Redlined]

Thanks for all the info! I'm learning things all the time from you guys. (( this is why I hang out here ))

Bigger Turbo is in the works. Not sure on designations and such but thinking about a TD05-16g (seems to be a popular choice without being overkill). But thats on the horizon still. Need a catless down pipe, the turbo Silencer Delete (in the works as we speak) and set up a TMIC and all its trimmings first. then ill worry about a Turbo. No sense in putting the cows out to pasture if there is no grass.

Turning down the boost.... eh. Ill just live with the sound for the time being. maybe put the snorkus back in if it grows to irritating.

[Adam West]

All that will make it louder...i.e. silencer/resonator delete. But it's a good noise. Not one for grandmas but good for enthusiasts. Good luck!

[Bane]

catless downpipe? then you'll want to squeeze in an intercooler... sound will definitely jump up a notch or two... but completely in a good way

i look at it as... if the wife had something important to say, she should stop saying it under her breath because if she's not almost shouting at me, i can't hear her at WOT

lol

[BAC5.2]

I'd focus your mind on other mods.

Invest in a turbo blanket and some Dynamat. Cover the passenger side firewall and the transmission tunnel in dynamat.

That should help damp the noise quite a bit.