Maintaining Turbo Speed During Shifting?

[Nevada_TDI]

I have heard one of the tune providers puts into the tune to prevent the turbo from spinning down during shifting. Has anyone heard of this? Would it make that much actual difference reducing RPM loss between quick shifts?

 

[Mongler98]

So what happens when you want to come to a stop?
I'm extremely sceptical of suck a tune and how it would work and not run the engine away or destroy gears and clutches. Must be a drag track sort of thing you could not use on the streets.



Learn how to heal toe in corners
Learn how to rev match shifting.
No need for craziness to do it otherwise.
You're clearly looking for faster times around the track. That means its 100% driver. Get better until your 100% confident you cant push your car any faster.

If your not on a track, stay away from such pipe dreams unless your this far down the rabbit hole or don't care how deep your wallet is.

And honestly, the solution is not in the turbo, it's with the trans. Manual shifting is for chumps on a budget in the racing world. Dual clutch paddle shifting autos can shift 1,000x faster than you can and do a better job too at trasnfering power.

My take away, forget it.

 

[Nero Morg]

Literally have never heard of heel toe driving until I came onto the forums here. Still don't do it. Definitely try to rev match though. As for tunes, I know Malone tunes will actuate the turbo to keep the tubro spooled during deceleration and shifting. I actually asked about it one day cause I noticed on decel I was getting 7psi boost still, but as soon as I gave it any throttle, it went down.
As for short shifting, depends on what you're trying to achieve. Remember, turbo gives most boost starting at about 2k, so if you're racing... Keep them RPMs up.

 

[jhax]

Yeah, you don't need to even use the clutch if you rev match. Smiley face

 

[roadlust]

So the turbo can spin without exhaust going through it?

 

[ToxicDoc]

So the turbo can spin without exhaust going through it?

Exhaust is always going through the turbo if the engine is on

 

[Fix_Until_Broke]

There are deceleration maps in the tune that control how fast the engine will decelerate as well as being able to vary the vane position and injection timing at high RPM/low load conditions (between shifts) to help keep the turbo spooled.

Ever hear a monster truck or other race engine blip the throttle and it almost immediately both increases and then decreases RPM back to an idle? Ever have a "normal" car do that? Usually it takes a second or two (or three) to come down - this is in the tune to prevent the engine from dying upon sudden throttle removal.

To echo Mongler98's opinion - it's an unnecessary "feature" for 99.999% of the time.

With a properly tuned variable geometry turbo, you won't have much/any lag.

 

[Nevada_TDI]

Thank you for the responses, I did not want to mention Malones name just in case it wasn't them.

 

[Mongler98]

FWIW, this is actually done with high performance F1 and other extreem type race engines. they use a massive electric motor bewteen the hot and cold side and use batteries to power it to make boost at whatever the tunner wants at 100% of the time if needed, downshifting can actually charge the batteries.
ive always had wet dreams of putting one of these on a car, even a TDI lol. the last time i priced one out was about $14,000 give or take, thats with the Li batteries too and the controller.

 

[[486]]

I dunno, maybe it's just being used to driving cars with larger junkyard sourced dinosaur-tech turbos

lag just isn't an issue
if you shift up where you're making power the turbo's gonna come back up in a second or less
if you're short shifting it for economy, you're obviously not trying to go fast so who cares if it takes 2 or 3 seconds for it to lug back into boost

 

[MATPOC]

FWIW, this is actually done with high performance F1 and other extreem type race engines. they use a massive electric motor bewteen the hot and cold side and use batteries to power it to make boost at whatever the tunner wants at 100% of the time if needed, downshifting can actually charge the batteries.

This is why they call it power unit, used to be KERS when they only harvested electricity conventional way from the drive motor, now they harvest from the turbo to recharge faster, and I guess keep the boost up. F1 tech is just silly, but some of it does trickle down to us plebs

 

[Pat Dolan]

E turbos are not F1 tech, they are available for production cars (not yet aftermarket). Garret is in the lead, but every major turbo manufacturer either has in development or has available electrically assisted turbochargers - even for very, VERY large marine engines. There are also pure electric centrifugal supercharges (essentially the compressor side of a turbo) that supplement the turbo side only by almost completely eliminating boost lag - bot of course not able to recover any energy - as well as what Mongler posted with a electric motor/generator in the bearing section (I think one design has it on a shaft with motor/gen outside on the cold side). Most run at IIRC 48 or 60 VAC but there is an voltage change box to interface with 12V (and I hope somewhere soon 24/28VDC - as one of these could eliminate the alternator, alternator drive, and the scavenging blower and drive for 2 cycle diesels)

KERS systems work by being driven from the gearbox from rear axle decel loads that are stored in batteries (to be released into a motor driving the crankshaft) or flywheel (released mechanically back to the rear/drive axle). I am sure the engine management system plays with the turbo a lot, and it IS possible they now use e-turbos (not sure, don't follow F1 any more).

 

[MATPOC]

KERS systems work by being driven from the gearbox from rear axle decel loads that are stored in batteries (to be released into a motor driving the crankshaft) or flywheel (released mechanically back to the rear/drive axle). I am sure the engine management system plays with the turbo a lot, and it IS possible they now use e-turbos (not sure, don't follow F1 any more).

F1 definitely harvesting power from the turbo shaft now, it might be short lived but AFAIK current
KERS was original system from 2008(?) when they harvested on the braking and were limited to 80hp for like 8 seconds a lap, I think they used some crazy capacitors
Next up was MGU-K (Had to look it up) some updates but essentially same system, more power
Current system is MGU-H and it's using e-turbo, been few years, all boring Merc domination, but still worth watching, especially when the alternative is watching my cat polish his balls

 

[Mongler98]

well, at least its not that really stupid compressed air system those old geysers made. Storing 2 80 gallon 2000 PSI scuba air tanks in the trunk just to eliminate a "parasitic power adder" their words, was by far the most asinine way to waste money, increase weight, reduce handling and look like an idiot for trying to make old tech work just a little bit faster/ better
but it did one thing very well, it definitely eliminated any lag!

I can't seem to find the video i was looking for but im sur eyou can search and find what im talking about, maybe people have added air tanks to give the turbo a direct shot of air to eliminate spool lag. NOT BOOST LAG. 2 completely different box of frogs so .... still not a very good idea, but i salute them for trying

 

[racerxtdi]

You need Anti Lag!!! But then again this a VW TDI not a Rally Car. Try a ball bearing turbo.

 

[TDIMeister]

The ECU map can simply be tuned to close the VNT vanes during throttle lift instead of opening them, which gives the characteristic "howl."

 

[MATPOC]

You need Anti Lag!!! But then again this a VW TDI not a Rally Car. Try a ball bearing turbo.

That bang-bang can be achieved on a NA car with a tune, I think they call it "crackle and pop", you basically pay money to make your car sound like **** every time you lift...

Antilag can be easily achieved with valve and ignition timing, cutting power at WOT but still producing "cold" exhaust gas flow. F1 teams were doing it to generate downforce with "Blown Diffusers" (I'm not making this up, link here http://www.formula1-dictionary.net/diffuser_blown.html ) so when the driver lifted in the corner, right when you need most downforce, engine still produced a lot of exhaust flow by manipulating valve lift, and timing as well as fuel and ignition. Same can easily be done with variable cam timing on a diesel, but you still burning some fuel so MPG suffers

 

[racerxtdi]

Yeah the video basically explains that. That b******* Crackle Pop that ricerss tune for is a joke.

There are bypass systems in place as well as Injecting fuel in the turbine housing. All these things cause extreme wear. Not really for a street car.