Hot take: Turbo + manual = slushbox

[brages]

So...

I'm a fan of manual transmissions; I find they are more enjoyable to drive and I believe that they are more durable and economical than autos. I have heard the today's new automatics are great, but I drive older (cheaper) cars, so it will be a few years before I can agree or disagree. At least by then, we will have a good picture of the durability of today's wonder-automatics.

Anyway, one of the reasons I like manuals is the instant response. I can anticipate a corner or opening in traffic and be shifted into the right gear. Then, when it's time to GO, just mash down the gas pedal and the car goes, no torque converter slipping, no waiting for a kickdown in gear.

Recently, I bought my first turbo car, a Volvo S40 T5 with a 6 speed manual. Now, this car has a fairly large displacement engine (2.5 5-cyl) for its size and has a fairly small, low-pressure turbo. So you would think it would spool up quickly, and the lag at low RPM's wouldn't be too bad. And it's not a peaky power delivery; it's a flat torque curve that comes on at low rpms, 1500 to 2k.

BUT, what I'm coming to realize is that the turbo lag is giving me a similar sensation to a "slushbox" automatic. Instead of hitting the gas and getting an instant response, I press the accelerator pedal, wait just a bit for the boost to build and then accelerate. And, yeah, it's kind of a fun sensation to feel the boost hit, but it's also annoying... instead of power output being just a function of rpm and throttle, now it's a function of rpm, throttle, and time.

So I'm wondering if anybody else has a similar feeling. Does turbo lag take away from the instant throttle response that makes manuals fun to drive? Does it just seem like turbos work better with automatics anyway, because the time to kick down gives time for boost to build? It seems like more small cars are going the turbo route these days. And everybody says they have "eliminated lag" but I am skeptical...

 

[UG_Passat]

I still prefer turbo + 6-speed manual vs turbo + Aisin 6-speed automatic.

If you I need to immediately speed up, I downshift on a manual, just like an automatic would, and spin up the turbo in the process while rev-matching.

 

[maxdustington]

The turbo lag combined with what I assume to be torque management during shifting my auto trans can cause my car to seemingly take off sometimes. I notice this a lot on left turns at lights, my car will rev up and hit boost right at the end of turn. The auto trans can downshift and hit boost at times when you don't want it to.

 

[edyvw]

Originally Posted by brages
So...

I'm a fan of manual transmissions; I find they are more enjoyable to drive and I believe that they are more durable and economical than autos. I have heard the today's new automatics are great, but I drive older (cheaper) cars, so it will be a few years before I can agree or disagree. At least by then, we will have a good picture of the durability of today's wonder-automatics.

Anyway, one of the reasons I like manuals is the instant response. I can anticipate a corner or opening in traffic and be shifted into the right gear. Then, when it's time to GO, just mash down the gas pedal and the car goes, no torque converter slipping, no waiting for a kickdown in gear.

Recently, I bought my first turbo car, a Volvo S40 T5 with a 6 speed manual. Now, this car has a fairly large displacement engine (2.5 5-cyl) for its size and has a fairly small, low-pressure turbo. So you would think it would spool up quickly, and the lag at low RPM's wouldn't be too bad. And it's not a peaky power delivery; it's a flat torque curve that comes on at low rpms, 1500 to 2k.

BUT, what I'm coming to realize is that the turbo lag is giving me a similar sensation to a "slushbox" automatic. Instead of hitting the gas and getting an instant response, I press the accelerator pedal, wait just a bit for the boost to build and then accelerate. And, yeah, it's kind of a fun sensation to feel the boost hit, but it's also annoying... instead of power output being just a function of rpm and throttle, now it's a function of rpm, throttle, and time.

So I'm wondering if anybody else has a similar feeling. Does turbo lag take away from the instant throttle response that makes manuals fun to drive? Does it just seem like turbos work better with automatics anyway, because the time to kick down gives time for boost to build? It seems like more small cars are going the turbo route these days. And everybody says they have "eliminated lag" but I am skeptical...

You will always have turbo lag. BMW N55 engine has 300 lb-ft at 1,200rpms, yet you still feel turbo lag.

 

[DriveHard]

Good thing you were not driving turbos 20 years ago...the lad could be measured in full seconds if managed poorly.

I have also noted that I believe some of the lag may be intentional, as to maintain decent combustion temps, and keep knock in check. There is also the dreaded fuel enrichment delay mandated by the government that makes the problem that much worse. Get a downpipe, and a tune, and many of your problems will be if not solved, improved.

 

[Virtus_Probi]

Might be a totally unrelated engine, but I test drove a "hot" Volvo wagon way back around 2006 and it had brutal turbo lag. I really felt like I would hit the gas, nothing would happen for a second or more, and then it would take off like mad. A second doesn't sound like a lot, but if you're talking about a car with a 5-6 second 0-60, that's a pretty good chunk of that time.
My FXT definitely doesn't jump when I hit the gas like my RAV6 did. I have read that this is partly due to the CVT and that the WRX with a manual and a very similar 2.0l DIT engine launches much better and that even the WRX with the CVT is not as laggy as the FXT.
I will say that the FXT really pours in on once it gets going and takes a long time to quit, I felt that one weakness with the RAV6 was its sorta crude 5 speed auto and it would often seem to get a bit lost after taking off. I turn left going up a somewhat steep hill once I get down the really steep hill when leaving my neighborhood and the RAV6 would often respond poorly once it hit that upslope...the FXT just takes off every time with no hesitation. I guess the RAV6 was still more fun to me overall, too bad Toyota stopped offering the 270HP option for the RAV...

 

[Pelican]

Never been a fan of turbos for this and other reasons, but I am a fan of superchargers, you don't have lag and you have all the power at low rpms (torque) but it's more expensive to manufacture if it is (as it should) incorporated into the block. So the manufacturers take the easy way out aided & abetted by the customer's ignorance on the subject.

 

[BMWTurboDzl]

Ya, you have it about right, although it really comes down to adjusting ones driving style to the car rather than the other way around. Even during sporty driving lag should never be an issue because rpms should remain well into the optimum range (>1k).

Other than moving off from a dead start, lag in today's' engines and their tiny turbos should be nonexistent.

BTW some of the ATs of today do not slip as in they're in full lockup the majority of the time.

 

[Trav]

Twin charging takes care of that problem and interestingly 7 psi boost on both units does not equal 14 psi its much more but its very difficult to implement properly.

 

[BMWTurboDzl]

Originally Posted by Pelican
Never been a fan of turbos for this and other reasons, but I am a fan of superchargers, you don't have lag and you have all the power at low rpms (torque) but it's more expensive to manufacture if it is (as it should) incorporated into the block. So the manufacturers take the easy way out aided & abetted by the customer's ignorance on the subject.



All true but one stills has the parasitic drag of having to turn the supercharger. Both have their pros/cons.

 

[Bottom_Feeder]

Maybe there's a mechanical issue with it? Leaking hose somewhere or some other problem?

 

[Srt20]

Smaller turbo, get rid of intercooler, plumb right from turbo to intake. Lag almost gone.

 

[ecotourist]

I had a Volvo 740 Turbo with a 4+1 manual transmission. It had the same problem. There was always a significant lag followed by a whoosh as it took off in a great rush.

At least I knew it was turbo lag. I've driven turbos with an automatic, where if you floored it at low speed there would be lots of roaring accompied by a similar lag, but where you couldn't tell what was happening - some combination of turbo lag, downshifting, torque converter slippage, and maybe even wheel spin - a totally unnerving sensation.

Where the Volvo excelled was highway driving. The turbo was always spooled up a little (or at least there was lots of exhause flow) and an upslope or a sudden need for passing power would be no sweat. And fuel economy was quite good for the era and considering the size of the car.

 

[RooflessVW]

It's not lag! You are under boost threshold and improperly driving the car. Try shifting down a gear before putting your boot in it.

 

[DaRider34]

Doesnt properly sized twin scroll turbos help make lag almost non existant

 

[Pelican]

Originally Posted by BMWTurboDzl
Originally Posted by Pelican
Never been a fan of turbos for this and other reasons, but I am a fan of superchargers, you don't have lag and you have all the power at low rpms (torque) but it's more expensive to manufacture if it is (as it should) incorporated into the block. So the manufacturers take the easy way out aided & abetted by the customer's ignorance on the subject.



All true but one stills has the parasitic drag of having to turn the supercharger. Both have their pros/cons.


There is always a price to pay one way or t'other

 

[skyactiv]

My wife owns an Audi A4 and I own a GTI. Both have a turbo and both cars have a stick. The turbo lag is a lot less than a WRX I once owned. My mom has a 2016 Audi A3 quattro with a DSG automatic which feels like a rocketship.

 

[LotI]

My GTI is my first turbo and there is definitely lag. Peak torque is rated at 1800rpm but there is no response there. Going on and off the throttle at low rpm results in nothing.

There is a need to keep it above 2500rpm when response is needed. Too much air volume between the turbo and inlet because of the intercooler is my guess.

 

[ls1mike]

Malibu is the 2.0 LTG Turbo 259hp and 295ft/lbs of torque. It has a twin scroll turbo charger and I was surprised at how little turbo lag there is.
My buddy has a 2006 WRX and lag is WAY more in that then the Malibu. Malibu is a slush box and the WRX a manual.

I remember the days of my old Turbo Dodges...you want to talk about lag? Those cars had TONS of it. New cars can't even compete.

 

[Linctex]

I have always hated automatics in any performance car until I started building & running drag cars with the right torque converter in them.

I can tell you this.... nothing compares to the sensation of going from 1st to 2nd in a "firm" shifting automatic with 850 lbs.ft of torque at FULL TURBO BOOST (24+ psi) .

In my drag car, the only things absorbing the torque was a tiny bit of tire spin (10" wide slicks) but not a lot spin at all, the torque converter handled/absorbed some of it,

.....but most of that power was absorbed by getting launched forward. HARD.
Oh, and the chassis flex was just unreal.
I didn't know a car could flex that bad - until it's having to cope with so much torque.