So I just got my 997.1TT Tip... literally yesterday... my first turbocharged car... sorry for the noob question ;-)

On the dash I set to view boost in PSI (number readout, not bar gauge). I noticed it reads 0 PSI normally when I'm driving (even in sport mode).

When I get on the highway and can floor it (very briefly ... for 1.5 seconds?) it climbs up to 5, 9 or max 12 PSI for about a second, then back down again to 0.

Basically it reads as 0 PSI unless the RPM is near to 4,000 AND I'm pressing the accelerator hard I think... and even with Sport Plus on, the Tip likes to shift before 4k RPM. I'm guessing the only way it holds a gear nearer to redline is when the accelerator is completely to the floor? Not easy to do in Chicago unless you go to a drag strip ;-)

Anyway I am just curious about everyone's experience with the boost.

1. Does my experience / car sound normal ?

2. Is there a particular RPM when boost kicks in?

3. Is it controlled only by RPM? Or is it a combination of RPM and how far down you are pushing the accelerator?

I know, I know, I need to get out the car's manual book. Just wondered if anyone had some real word tips on when the boost kicks in...

 

Sorry additional question

4) I am seeing 0 PSI 99.9% of the time when I drive my 997.1 TT Tip. Only time I see any boost (3, 5, up to 12 PSI) is briefly when I "floor" the gas and the RPM's hit 3,000 to 5,000. Might last a second or two then back to zero. Reading some other threads I'm beginning to wonder if this is an issue. Also wondering if maybe my car was modded; it does have a Fabspeed exhaust but was sold with 11 months of warranty on it. I don't think the dealer inspected the car much but I did insist they give me paperwork that stated the car had 11 months of warranty left. I might be making a mountain out of a molehill because besides wondering about this PSI gauge issue the car seems to drive good... smooth up when I take it easy and fast when I floor it!

 

OK last post ;-)

I found this thread helpful:

https://www.6speedonline.com/forums/...rbo-spool.html

Now I am wondering if I just am not gassing it enough (pressing down on the accelerator). Again, I live in Chicago -- potholes and crazy traffic everywhere -- very hard to get a few hundred years of "runway" to push this car.

Maybe the boost kicks in, as a function of how hard you press the accelerator? E.g if you never press it down more than 30% of the way down, the boost doesn't kick in?

 

I can only speak from experience in my 997.1TT Manual but boost only comes on when the engine is under load. I am not a technical person so excuse my description but the majority of the day I cruise around in my TT no boost is used at all. When I push the engine beyond what I think the 3.6L can handle on its own then the turbos spool up and the boost kicks in. If you only floor it for 1.5seconds it makes sense that the TT blows boost and dies off when you let off the gas.

Boost usually kicks in around 2800 rpm and under the "load" conditions.

I dont know if this even helps but everything sounds normal.

Good Luck. I am sure someone more savvy can chime in with a better answer.

 

Awesome -- thanks for the help!

> Boost usually kicks in around 2800 rpm and under the "load" conditions.

So from this tip from you, and from what I've read on the other threads... I can expect "non zero" PSI boost in my 997TT Tip when BOTH:

1. RPM over 2800
AND either
2a. Going uphill OR
2b. Pressing down on the throttle hard (maybe to the floor , or nearly to the floor)

?

As a side note. Still loving my new toy. But the above analysis makes me smile. I can barely get it into 3rd gear 2500 RPM in the city here and the turbo is rarely kicking in. Summing up the 997TT in two words:Hilariously overpowered?

 

That sounds correct to me.

Have fun and enjoy the ride.

 

Courtesy of Wiki...

"Turbochargers start producing boost only when a certain amount of kinetic energy (i.e. momentum) is present in the exhaust gasses. Without adequate exhaust gas flow to spin the turbine blades, the turbo cannot produce the necessary force needed to compress the air going into the engine. The boost threshold is determined by the engine displacement, engine rpm, throttle opening, and the size of the turbo. The operating speed (rpm) at which there is enough exhaust gas momentum to compress the air going into the engine is called the "boost threshold rpm". Reducing the "boost threshold rpm" can improve throttle response."

 

Try going 60 -> 80 on the freeway. You don't even need much gas to get some nice whistling in the back.

 

I only have experience with manuals, but I would think you should see higher numbers than 12 psi especially under sports mode? Get on one of the tollways, like 88 or 294 early in the morning and punch it for more than 3 sec. while cruising in 5th gear in sports mode and see what happens to the boost level.

 

Ha I don't want to sound like a dweeb, but wouldn't punching it for more than 3 seconds in 5th gear, get you to 100mph?

Is there any way to get the turbo boost working at lower speeds? Since it's partly a function of throttle pressure, maybe "flooring it in 2nd to 3rd gear" is the earliest you can get boost to kick in on a 997TT Tip, speed wise?

 

I can see how load testing may be difficult with Tip since it will just downshift when you floor it while in top gear.

 

Brake boost if you want it. Hold it for 2 sec at 3300+ and hang on. The 3.6 motor is a VERY good motor and adding boost as you stand on it is that much better. You really dont need boost for 0-35 unless you are doing 1.5 sec runs from light to light. Although you willl be going 80 before most cars are at 40

 

Turbos make intake boost from the exhaust gas turning the hot side of the turbo. You have to have some exhaust going to create boost. This is where the term turbo lag comes from. You will not begin to see boost until around 2200 or so rpm. However, if your car does not need the boost to do what you are asking, it will divert the boost pressure and not build boost. That is done through the wastegate and diverter valves on the car.

Being that you are hitting the throttle for only a short period of time, you are only going to see boost pressure while you are in need of it. Remember, the cars engine is a vacuum pump and has vaccum present until you are at or near wide open throttle. In a NA car, at wide open the vaccum drops to 0. The advantage of a car with a turbo or supercharger is that it can create a positive vaccum ( BOOST ) and give your. More air into the cylinders. Making you go zoom!

As for not seeing boost at lower speeds. Floor the pedal from a stop. You will see boost sooner. Just be careful, you sound like you may just be a little on the rookie side of things. The car will go very quick very fast. Ma,e sure you have room and know the road.

Lastly, excuse any poor spelling. The iPad keeps correcting me and I got tired of fighting with it...

Mike

 

As someone mentioned, some of your questions will be answered as you get more seat time and become familiar with the car. You may want to play with (toggle) various gears. Simple city driving in auto mode will result in minimal boost. Try putting the car in lower gears around town and downshift before throttling up. You'll begin to find it's really fun to drive that way and when stuck in traffic you can just leave it in normal auto mode. You'll also learn how the computer adapts to your driving habits. Hard driving in sport mode and the vehicle with holds gears longer and behave differently. Turn it off and it switches back.

 

Oh and the tip wont downshift till you press it to a certain point. Or you can hit the - button.
I know you are looking for max boost but to get it you will need to have a long straight road and no cops because when you get your max boost you are in felony territory.

There is almost NO LAG on a tt because of the Variable Vane Technology on the TT. You just need to push the fun pedal. Again, if you have short roads or limited area to do this you will run out of road fast. Remember the car goes 0-100 in under 7.7 seconds that is 100MPH and its going to be building speed. So while max boost would be really fun, you need the space and safe conditions to do it.