Boost curve for TVS?

[drh_5.0]

Sorry if there is a thread on this, at work don't have time to go looking!

How does boost work with a TVS? Is it like a centrifugal still in the fact they both gain boost with higher RPM's...

OR

Does a TVS give peak boost instantly on throttle (WOT)?


I would think they both need to rise as RPM rises but I don't know... I hear some people say the Centri's dont show boost until 3500-5k RPM?

Say if I were to just be cruising at under 3k RPM, would I be in boost with a TVS?

 

[mebcop]

If I go WOT at 2500rpms I have about 7psi of boost and I'm up to 8.5-9psi by 4000rpms and hold that to redline. Can timing in the tune can effect your boost though, just so you know.

 

[Scott8583]

Your not running boost unless your under load... I don't use a boost gauge, but boost is almost instant. I launch at the track at 1500rpm (automatic) & it pulls hard!

 

[drh_5.0]

If I go WOT at 2500rpms I have about 7psi of boost and I'm up to 8.5-9psi by 4000rpms and hold that to redline. Can timing in the tune can effect your boost though, just so you know.

Awesome, good info there. Thanks! Yeah hoping to not have to much cam timing changed unless it needs to be!

Your not running boost unless your under load... I don't use a boost gauge, but boost is almost instant. I launch at the track at 1500rpm (automatic) & it pulls hard!

That's what I like to hear. Is it the bypass valve that keeps the car out of boost until under a load? I bought a boost gauge and will be installing that very shortly after the S/C...want to be able to monitor boost levels

 

[corepwn]

Awesome, good info there. Thanks! Yeah hoping to not have to much cam timing changed unless it needs to be!

That's what I like to hear. Is it the bypass valve that keeps the car out of boost until under a load? I bought a boost gauge and will be installing that very shortly after the S/C...want to be able to monitor boost levels

The tvs will make full boost immediately once the bypass is closed. The only thing that changes this so that it might be lower is how the cam timing is setup for a particular tune.

At low throttle the bypass is open and you're not in boost.

So the curve is basically full boost at any room at WOT

 

[drh_5.0]

The tvs will make full boost immediately once the bypass is closed. The only thing that changes this so that it might be lower is how the cam timing is setup for a particular tune.

At low throttle the bypass is open and you're not in boost.

So the curve is basically full boost at any room at WOT

Does the bypass close only during WOT?

 

[cb900f]

Does the bypass close only during WOT?

No it will do it about half throttle ish.

 

[mebcop]

No it will do it about half throttle ish.

I think it depends more on how your tuner sets up your throttle sensitivity/ delta throttle/ etc tables in your tune.

 

[drh_5.0]

Didn't even think about that! That sounds like how it would work...tune dependent. I think of when I had just N/A mods and BAMA tunes in the beginning...and the street tune was very different from the race tune. Race seemed like half throttle was WOT...while street was pretty much a stock throttle feel.

 

[mebcop]

Didn't even think about that! That sounds like how it would work...tune dependent. I think of when I had just N/A mods and BAMA tunes in the beginning...and the street tune was very different from the race tune. Race seemed like half throttle was WOT...while street was pretty much a stock throttle feel.

Exactly.

I think that when u get a tune, sure you gain a little tq/HP, but the power delivery difference you feel is more from a more sensitive throttle. You hear guys all the time "after my tune my car is so much more responsive", well ya, because when you go half throttle with the tune, the ecu might be commanding 3/4 throttle at the TB.