When does the turbo kick in?

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Old Feb 14, 2008 | 10:01 PM
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When does the turbo kick in?

I took a test drive of the RDX but didn't really get a chance to test its limits because the sales person was with me. In fact I hardly got it above 30mph. From what I could tell the turbo never kicked in.

At what point (RPMs) does the turbo kick in during normal driving situations? I'm not too heavy on the peddle and would hope it doesn't come on all the time during regular driving (this would be my first turbo - can you tell?) Obviously there are days I will like it and therefore will want the turbo to kick in but on a regular day to work where I have regular city driving I would prefer it doesn't kick in unless I floor it.

Thanks in advance for any feedback. I think I need to get another test drive...alone...next time.
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Old Feb 14, 2008 | 10:15 PM
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Actually if your heavy on the throttle then yes it will spool up quite a bit.

btw sales people don't give a rats ass about how you drive the car, I test drove a tsx a while back and the guy is like floor it.
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Old Feb 15, 2008 | 03:27 AM
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yeah - you're bad for not pushing the envelope...i'd go back and drive it again. You don't spend $35k for a high performance vehicle and don't get it over 30 during the test drive...

I had my sales guys ears pinned back on my test drive.

I've got an 07, but the turbo is definitely pretty lively if you have a heavy foot. I've learned how to drive it in traffic and through town so that I can minimize the turbo boost for MPG sakes, but even then it will kick in now and then.
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Old Feb 15, 2008 | 05:22 AM
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You can tell the turbo kicks in by the boost meter


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Old Feb 15, 2008 | 08:24 AM
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Turn off the Stability control and floor it.
It will be obvious. ;-)

It seems to start spooling up between 2500 and 3K.
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Old Feb 15, 2008 | 08:29 AM
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Talking are you serious?

30 mph? What did the salesman only let you drive in a parking lot? Did you get out of first gear? The RDX has a nice little power and torque band. Trust me you will know when the turbo kicks in!
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Old Feb 15, 2008 | 09:15 AM
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Did you have the parking brake on?
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Old Feb 15, 2008 | 12:36 PM
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Originally Posted by RENARELLO
Did you have the parking brake on?
ha ha no I'm in Boston so it was a lot of city driving. Can't really get up above 30-40mph when you're on city streets. But I'll probably take it for another drive to try and push it some more. Ideally by myself.
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Old Feb 15, 2008 | 01:14 PM
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Originally Posted by phoward_15
I took a test drive of the RDX but didn't really get a chance to test its limits because the sales person was with me. In fact I hardly got it above 30mph. From what I could tell the turbo never kicked in.

At what point (RPMs) does the turbo kick in during normal driving situations? I'm not too heavy on the peddle and would hope it doesn't come on all the time during regular driving (this would be my first turbo - can you tell?) Obviously there are days I will like it and therefore will want the turbo to kick in but on a regular day to work where I have regular city driving I would prefer it doesn't kick in unless I floor it.

Thanks in advance for any feedback. I think I need to get another test drive...alone...next time.
It seemed to me, one test drive only, that the turbo was brought online immediately with only the slightest level of acceleration required. Obviously it cannot provide any significant level of boost until "spool-up" and even with the light weight low inertia RDX turboes that means some level of noticeable delay.


see:

https://acurazine.com/forums/showthread.php?t=2264
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Old Feb 15, 2008 | 01:54 PM
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Originally Posted by phoward_15
ha ha no I'm in Boston so it was a lot of city driving. Can't really get up above 30-40mph when you're on city streets. But I'll probably take it for another drive to try and push it some more. Ideally by myself.

Dude, got to Peabody Acura and look for Bill M-something. He was my sales guy, he's a car guy, and he let me beat the bag out of their demo RDX. It was great.

Fwiw, the RDX turbo can spool up quite quickly and low in the rev-range, which is great.
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Old Feb 15, 2008 | 10:28 PM
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Salesmen don't know much about cars, but they do know how to identify a buyer's "targeted interest features" and continuously redirect toward those.

Just tell him you are interested in acceleration and handling. If he was paying attention at the sales retreat, he will emphasize this throughout the drive.
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Old Feb 16, 2008 | 04:57 PM
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I took my salesman on a hell of a ride..LOL we took an infinite like 5 times, tires squealing all the way through after the first 2 laps...drove back to the dealer and signed some papers.
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Old Feb 16, 2008 | 07:27 PM
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Agreed...

That does seem like a newbie salesperson. I guess my experience mirrors what other buyers had. Our salesperson wouldn't let us leave without showing off all the acceleration and traction capabilities. While we were deciding, it rained one day, and he called us up "Hey, this is a perfect time to see the traction control in action" and we drove the hell out of the demo car there. High speed braking from highway speeds, quick back and forth to try and unsettle the car in the rain, etc. From a complete stop, full pedal down acceleration with no slippage. Fantastic.

Loved it, it definitely helped close the deal with us.
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Old Feb 17, 2008 | 09:36 AM
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I have an 04 NBP TL and i went to acura yesterday to test drive the RDX and i will say i was very surprised on the performance. The power matched up nicely with the TL and im actually convincing my father to buy it.... its a great car really fun to drive and the has a nice turbo in it i hope that we will be adding this car in my family
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Old Feb 17, 2008 | 01:29 PM
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i was told here are the keys, the speeding tickets are mine...haha i had a good test drive.
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Old Feb 17, 2008 | 05:37 PM
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Originally Posted by neo1738
i was told here are the keys, the speeding tickets are mine...haha i had a good test drive.
Yeah the more I look back on my experience and read posts on here the more I realize the sales guy I had was a newbie. And he was horrible too. Maybe that's why it wasn't the best test drive experience. I liked the ride overall and thought it was pretty smooth. Just didn't get to test the engine.

I know the turbo starts spooling up around 2K-3K rpm but wanted to know at what RPM does the valve open up and it actually kick in....at 4500rpm, higher, lower? I was just trying to get an idea based on my style of driving how often I would use the turbo.
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Old Feb 18, 2008 | 09:59 AM
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there is no valve that opens up on turbos. It spools/spins up and forces compressed air into the engine, that's it. If it's spooling up, it's "working".
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Old Feb 18, 2008 | 10:16 AM
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Autoblog did a pretty good writeup on the engine recently:

http://www.autoblog.com/2007/11/22/l...ne-on-display/
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Old Feb 18, 2008 | 10:18 AM
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Originally Posted by JGard
there is no valve that opens up on turbos. It spools/spins up and forces compressed air into the engine, that's it. If it's spooling up, it's "working".
Not true in this case:

http://www.acura.com/index.aspx?init...owTurbocharger
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Old Feb 18, 2008 | 12:12 PM
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Originally Posted by oasis3582
Thanks Oasis this was really helpful. I knew the turbo had a valve on it.
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Old Feb 18, 2008 | 01:32 PM
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Originally Posted by oasis3582
What I said is still true! This valve you're referring to is merely for the exhaust that's propelling the turbo and allowing it to spool up more quickly than it otherwise would.

So as long as the turbo is spooling and you see the boost gauge working, which it's generally always doing if your foot is on the gas pedal and the RPMs are above 2,000RPM, then the turbo is "kicking in".

A turbo is not binary, either. It's not either all or nothing. Turbos can spool a little and still create a slight positive pressure inside the intake manifold.
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Old Feb 18, 2008 | 02:30 PM
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Originally Posted by JGard
A turbo is not binary, either. It's not either all or nothing. Turbos can spool a little and still create a slight positive pressure inside the intake manifold.
I am guessing this is why the boost gauge is analog then
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Old Feb 18, 2008 | 03:35 PM
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Originally Posted by JGard
What I said is still true! This valve you're referring to is merely for the exhaust that's propelling the turbo and allowing it to spool up more quickly than it otherwise would.

So as long as the turbo is spooling and you see the boost gauge working, which it's generally always doing if your foot is on the gas pedal and the RPMs are above 2,000RPM, then the turbo is "kicking in".

A turbo is not binary, either. It's not either all or nothing. Turbos can spool a little and still create a slight positive pressure inside the intake manifold.
Ahhh that's very helpful. So I'm assuming that since the turbo is almost always on it's burning more fuel than if it wasn't. I'm amazed at some of the mpgs people are getting if that's the case (i.e. I've heard of 23+ mpgs).
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Old Feb 18, 2008 | 03:47 PM
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well, again, it's neither on nor off. It's always spinning. Whether or not it's spinning fast enough to create positive pressure inside the manifold is another story.

My RDX has only 800 miles on it still and I'm barely seeing 20mpg combined...but I also floor it...a lot. I have noticed that if you cruise on the freeway around 55-60mph, there's rarely boost and gas mileage is pretty good. However, if you want to cruise around 80mph, there is almost constantly boost and fuel consumption is not so good (from my experience, about 19mpg).

Most people report that they don't see their best fuel economy until a few thousand miles into the life of their car, though, so it could be way different for other folks.
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Old Feb 18, 2008 | 04:37 PM
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It would be highly unusual for an exhaust gas driven turbo to NOT have a wastegate to bypass the turbo's incoming exhaust "charge" once maximum boost level is reached. The pictorials show two vacuum motors, one for the variable vane actuation and the other, I suspect, for the wastegate.

Assuming there is a wastegate it would be extremely unwise not to use it to bypass the boost level at times when the ICE torque is more than adequate to move the vehicle along briskly at any reasonable, constant, cruising speed and with a "tow".

But on the other hand given the unusually low FE being reported of the RDX maybe even if it has a wastegate it isn't being used to bypass boost at low torque demand levels....

But IMMHO the whole thing is a "can of worms" design to begin with.
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Old Feb 7, 2024 | 08:29 AM
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"But IMMHO the whole thing is a "can of worms" design to begin with."

Haha, this aged well...
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