Temporary overboost is a thing of the past ?

[Tmoose]

An online acquaintance claims "Temporary overboost is a thing of the past."

I know a friend's 198X Chrysler Turbo had it.
I'm pretty sure I recently read that some Volvo was using "it" within the last year or so.
"It" being several psi extra boost for a relatively short time (on the order of 10 or 20 seconds) when full throttle is initially summoned, which is then dialed back for more sustained abuse.

Does anyone know of recent factory offerings ?

thanks,

Dan T

 

[MikeHalloran]

I hadn't heard of intentional temporary overboost, but it doesn't surprise me.

Ten-ish seconds is a couple time constants of typical turbo structure.
If you didn't limit the time, you'd have to use a more expensive alloy.



Mike Halloran
Pembroke Pines, FL, USA

 

[Tmoose]

Regarding the 1980s Chrysler system - this quote from Allpar is about as I remember the owner's manual describing it -
"The system allowed overboost during “snap acceleration” for up to ten seconds,

http://www.allpar.com/mopar/22t.html

Along with limiting boost in first gear for the benefit of the transmission, Which I beolieve is done by others much more recently.
=============

 

[RossABQ]

Ford Focus ST....

http://blog.athensofford.com/athens...s-st-features-factory-overboost-turbo-engine/

 

[SomptingGuy]

My understanding was that transient overboost (for diesels, at least) was allowed because conservative estimates of limiting temperatures were based on steady-state conditions. One company published a transient 30% torque bonus using this.

- Steve

 

[Tmoose]

Thanks Ross ABQ. that link (and a few additional ones if I find/receive them) will save un-necessary debate.

Hi SomptingGuy, would you happen to recall the manufacturer? I'd like to put that in the torpedo tube too.

Dan T

 

[GregLocock]

It is used by at least BMW, Fiat, Ford, GM, Mini in current production. It has been used by Lambo, Lotus, Mitsubishi and no doubt others in the past, if not the present.

Obviously there is little point in first gear for most cars, but in 3rd or 4th it is great.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[SomptingGuy]

My little Ford Focus diesel has it. Sometimes I'm reminded of my old RD350 when I floor it.

- Steve

 

[SomptingGuy]

An openly available document. Quite old now, but still very relevant.

http://www.ricardo.com/Documents/Do.../Papers/wave_matalb_concurrent_simulation.pdf

- Steve

 

[loki3000]

newish focuses, fiats etc. have it, but it's not much (maybe 10% in torque)

 

[TheBlacksmith]

My 2013 Focus ST has temporary overboost and temporary overrev. Just need to download the temporary tire hookup app.

 

[Tmoose]

thanks all.

The naysayer has become very, very quiet.