Well, I'm already pretty sure I know the answer, but I'm gonna ask anyway.
With a turbocharged engine, when running at freeway speeds (70-80mph) and RPMs (2500-3000), and when using a small turbo, like a T3 Super 60, is there any boost pressure built up? I know you hook a vacuum line to the bypass valve to open the valve when a large vaccum forms (like when getting off the throttle quickly), but would the bypass valve also be open during steady-speed high-speed cruising, since this is also a time of high engine vacuum? I'm just wondering because I'd really like to bump my car to an acceptable power output and not sacrifice freeway gas mileage and unnecessary strain on the engine when it's not needed.
So, if somebody could set my lame ass straight, it would be greatly appreciated
Well for starters a Super 60 isn't really a small turbo. You wont really spool fully till you hit close to 3200rpm's. I have a T3 50 trim and i don't spool till close to 3500rpm's. But even when i am spooling on the freeway i still get very good gas mileage. I wouldn't be too concerned about gs mileage till you are at full boost.
Veritas Aequitas
Even with a small, fast spooling turbo you can easily cruise around town or on freeways out of boost and get good gas mileage. Whether from a dead stop or with the car already moving, when you get into the throttle more and put a decent load on the engine is when the turbo will spool.
The blow off valve will only open when the vacuum spikes when the throttle closes. There's more vacuum when the throttle's fully closed at idle than when you're actually driving the car, and the valve stays closed at idle, so it'll stay closed when your driving the car with the throttle slightly open.
_________________________________________
450WHP Turbo Ecotec swap in the works...
In my car my turbo helped my gas mileage. I was getting 34mpg on the highway with just the hahn stage 2 bolted on.
Darryn
2004 Cavalier coupe, 5 speed, White
GO
Hahn Stage 2, Eagle rods, Wiseco 8.9, SS Valves, Dual valve springs, valve job, Ti seats and retainers
spec stage 3, Fidanza 7.5lb flywheel, Short Shifter
Slotted and dimpled rotors, EBC green stuff
SHOW
VIS EVO CF hood, KOBE KAM 5 17", Nexxen N3000, Ebay Black tails and filler, 5% tint
Gold line springs, Tokiko D-spec struts
ELECTRONICS
Kenwood in-dash DVD and Navigation, single Kicker CompVR
http://www.cardomain.com/ride/2974835
My mileage went down a touch... but it probably doesnt help that i kind drive like a dumbass now. i like going fast what can i say
Veritas Aequitas
Brown Eye wrote:Well, I'm already pretty sure I know the answer, but I'm gonna ask anyway.
With a turbocharged engine, when running at freeway speeds (70-80mph) and RPMs (2500-3000), and when using a small turbo, like a T3 Super 60, is there any boost pressure built up? I know you hook a vacuum line to the bypass valve to open the valve when a large vaccum forms (like when getting off the throttle quickly), but would the bypass valve also be open during steady-speed high-speed cruising, since this is also a time of high engine vacuum? I'm just wondering because I'd really like to bump my car to an acceptable power output and not sacrifice freeway gas mileage and unnecessary strain on the engine when it's not needed.
So, if somebody could set my lame ass straight, it would be greatly appreciated
Most gas related issues are going to be related to how well it is tuned. Given its a jbody, there is probabally room for improvement when it comes to that.
___________________________________________________________________
Mitsu TD06-20g |3" Downpipe w/ Cutout | 61mm Bored TB |
HP Tuners | Innovate WB02 | Spec Stage 3 | TurboTech Upper | Full Addco Sways | Sportlines & Yellows |
My bov kinda whistles at a certain throttle position when cruising. But I do have it set kinda soft so thats prolly why.
