Truck Turbos?

[Howitzer]

The Scandanavians seem to be getting some rather good numbers by using massive truck turbos on their crazy Volvos.

Now considering the price a pair of turbos from a Scania would be, why aren't these being widely used in the UK yet? I'm tempted to try them on mine but wondered if there was any inherant weaknesses in using them? Are they just not designed for such high speed as I would have thought they would see more load in a truck than a car?

Dave!

[tribbles]

Isn't this the same thread as this one?

http://www.pistonheads.com/gassing/topic.asp?h=0&a...

?

ETA: Might not be exactly...

Edited by tribbles on Monday 1st October 19:32

[Howitzer]

Not really, but thanks for the heads up as I hadn't seen that one !

Dave!

[thong]

got a big turbo off a scania truck,if you want be quick before i put a can on the side of it and fire it up

[BB-Q]

Jens Gustaffson got 505whp on his 142 using a Holset HX50 on a 40 year old 2.0l pushrod engine using mainly stock internals(the kind of turbo you get on an arctic). It's a discipline that's slowly coming out of Scandanavia, yes.

[900T-R]

So - what kind of rpm does such a beastie need to provide positive boost on a low-compression 2.0 litre mill? And how long for it to get to that stage when flooring it from a trailing throttle? Sounds like one that's strictly for the drag racing crowd...

[chuntington101]

900T-R said:

So - what kind of rpm does such a beastie need to provide positive boost on a low-compression 2.0 litre mill? And how long for it to get to that stage when flooring it from a trailing throttle? Sounds like one that's strictly for the drag racing crowd...

depends on the turbo! normally i think you spec the turbo on the airflow it can diliver. all turbos are rated on that. diesel turbo are usually VERY small. they dont need to be massive as even the big stuff wont make much over 500bhp!

another good point to deisel turbos is there are designed to run at HIGH presures that the deisels like to run. this menas the turbos will take 35psi no problems.

thanks Chris.

PS andone got any data for the Holset turbo range???

[eliot]

chuntington101 said:

PS andone got any data for the Holset turbo range???

Ive got some holset maps, drop me a mail at eliot@ mez etc.. - they were off the internet, so they are about.

Diesel turbos tend to have large compressors and small turbines - and at least on some, the turbine isn't designed to take the heat of a petrol engine exhaust. Many dont have water cooling for the same reason.
And as chris said, they run at high pressures - so the compressor map sweet spot is at a higher pressure ratio.

[chuntington101]

eliot said:

chuntington101 said:

PS andone got any data for the Holset turbo range???

Ive got some holset maps, drop me a mail at eliot@ mez etc.. - they were off the internet, so they are about.

Diesel turbos tend to have large compressors and small turbines - and at least on some, the turbine isn't designed to take the heat of a petrol engine exhaust. Many dont have water cooling for the same reason.
And as chris said, they run at high pressures - so the compressor map sweet spot is at a higher pressure ratio.

will do mate.

thanks Chris.

[jacko lah]

The HyBRID turbo ? Centre Housing with water cooling and Big Crompressor wheel is the way to go for more Boost on a small petrol engine. I'll not discuss LAG.

Petrol Exhaust is 200 deg C hotter than Diesel. Hence NEED water cooling.

[eliot]

jacko lah said:

Petrol Exhaust is 200 deg C hotter than Diesel. Hence NEED water cooling.

The water cooling is to keep the centre section bearings cool, especially after shutdown to avoid coking the bearings.
A turbine that gets too hot (because its designed for a diesel) can suffer "mushrooming" whereby the whole turbine warps and then collides with the housing causing permanent damage.

[BB-Q]

I've had an email from Holset stating that their turbos are not capable of use on a petrol engine due to the higher exhaust temperatures.
I responded that Holsets are used on thousands of petrol turbo cars and also on a 7 second Volvo and the fastest street legal car in the world.



I'm still awaiting Holset's reply.

Someone who is in the know has told me that Holset are quite happy with their massive OEM commercial market and have no interest in the performance market, hence their denial in the face of massively overwhelming evidence to the contrary.

[Howitzer]

I've seen 700degrees C on a Tractor exhaust before and it ran reasonably happily.

Would such short stints at WOT really do that much damage, I mean a big power drag car is only at full throttle for 10 seconds or so?

Dave!

[BB-Q]

The EGT's on a well tuned turbo car should be around 700C anyway, so there really shouldn't be a problem.

Look at it this way- if you were constantly at full production levels, doing millions in trade with massive OEM contracts, do you concentrate your rescources on keeping that huge market happy or venture into unknown territory?

The fact that you've seen 700C EGT's on deisels means that Holset will have tested to that and beyond, so there's really nothing to worry about, in my opinion.

[chuntington101]

jacko lah said:

The HyBRID turbo ? Centre Housing with water cooling and Big Crompressor wheel is the way to go for more Boost on a small petrol engine. I'll not discuss LAG.

Petrol Exhaust is 200 deg C hotter than Diesel. Hence NEED water cooling.

as eliot said the point of water cooling the centre sections is to keep the bearings cool after shutdown more than anything. alot of the 'race' turbos dont bother with water cooling.

as others have said, holset turbo have been used on some very fast petrol cars!

also you cant just bolt a BIG compressor housing onto a small turbo. you need to match the the turbo to the engine size and the power you want to make. Garrett GT units can all take MASSIVE boost without problems (they are designed to).

thanks CHris.

[BB-Q]

But you'd be very lucky to get a GT in a breakers yard- can't say the same about a Holset

Actually, a friend of mine has just imported a GT28 from ATP Turbo in the USA. He bought the complete kit, with oil feed, drain, actuator, their own awesome wastegate, etc. With shipping (4 days) and customs charges it came to less than just the turbo would've cost here!