Diesel Turbos vs Petrol Turbos

[HARDCORE]

Sorry if this a stupid question (a lot of my threads seems to start with that ;D) but are there any differences between turbos for petrol engines and turbos for diesels engines?

I have a turbo I'd like to put on my Audi dizzle but it's originally from a petrol..

Thanks!

[1980escort]

I'm sure somebody with more knowledge will be along to inform you better but I always thought diesel turbos were smaller as the work at different levels of boost and compression than petrol turbos

[OVY871]

There is a thread along the same lines as this one here.
If I remember rightly though I don't think you can swap them between, but read through the thread in case I'm thinking of something else.

[dude]

Should be no problem at all, as long as it's not too small, which will make it overheat and blow hot air, or too too big and make your car boring to drive due to massive lag.

If it's cheap and you need a turbo just go for it. If it's of a petrol it's usually big enough, but when using turbo's scrounged from diesel engines for a petrol engine you usually want the diesel engine to have quite a bit more displacement.

[DavidB]

I was told diesel turbo's aren't recommended for use with petrol engines because of the temperature differences - I was going to do the same but someone managed to heat the turbine and casing up enough to make it fail and enter the engine.

[dude]

Oct 27, 2012 18:35:52 GMT DavidB said:

I was told diesel turbo's aren't recommended for use with petrol engines because of the temperature differences - I was going to do the same but someone managed to heat the turbine and casing up enough to make it fail and enter the engine.

Tell that to everybody running holsets on everything from 220hp volvos to 1000++ v8's, 2jz and the likes

Sure, if you rip the turbo of a 110 hp 1.8 diesel and attach it to a 2 litre petrol engine i'm sure you'll run into a bunch of trouble, but if you spend 15 minuts googleing the turbocharger in question i'm sure you'll come to a conclusion if it fits your application or not.

[mdh]

EGT in a petrol are higher than a dizzel so turbos can suffer if they're not up to it.

Other way round shouldnt be a problem.

[chairchild]

only thing to really watch out for, is that as above, the EGTs on a diesel, are FAR lower than on a petrol. As a result, there's less volume of gas to flow through the turbine, meaning the turbines on diesel turbos are far smaller than the equivalent capacity petrol turbo

[TurboDieselWeasel]

I've been told the EGT is only a real problem when using a VTG turbo of a derv on a petrol engine

[chairchild]

Yups - the heat of the petrol EGTs are far beyond what the vanes were expected to have to endure, so they *could* expand too far, and seize solid. It's also more damp than a diesel exhaust, so slight surface rust can build up, and kill it also

Apparently Porsche have made some petrol-specific VNTs? But they cost a LOT more....

[DavidB]

Oct 27, 2012 18:51:07 GMT dude said:

Tell that to everybody running holsets on everything from 220hp volvos to 1000++ v8's, 2jz and the likes

Was an Isuzu1.7TD on a Vauxhall 2.0 8v

[HARDCORE]

Interesting readings, thanks!

The swop in question is the standard T2 (on my Audi IZ 1.9 TDi) for a T25 (from a Saaaaab turbo petrol) - if I've read the right things that's a direct replacement, but max flows around 400cfm, compared to ~300 for the T2.