Is it possible to use a diesel turbo in a petrol engine? I know that in the past the heat was ment to be too much, but heard that nowdays most diesel turbos can cope with a petrol engine.
With diesel turbos pushing 150+ hp from 2l engines, more if chipped I cannot see the exhaust temps being much lower.

Of course there is the issue of the compressor maps, different rev range etc.

Darren

is there something that requires doing for the wastegate ? as they are slightly different to petrol units

Most modern units have varible vane technology - effectively like swiching the turbine fitted on the fly. I guess they might not cope well if the temp is much higher.

I think there are sill a lot of normal wastegate types as well.
Darren

[Edited on 10/6/10 by turbodisplay]

I don't think it's viable as they are all a bit small, they can push the pressure out alright but only really for an engine requiring 5Krpm max, when you're on about 7k and maintaining the boost level they can't cope.

You should see the size difference between my tdi unit (approx 3.5"diam) making 1.63 BAR and my workmates Celica GT4 unit running 1.35 BAR (approx 6" diam) !!

And they are both on the limit as far as boost goes

I guess if it was a low boost app though it might work, but it's to do with CFM IIRC

HTH

Stott

You could run them as twins but longevity would still be an issue

my mate is supercharging a rover v8. The supercharger is a massive turbo from a very large mariene engine. It must be about 200mm in diameter

Regarding heat I can see that he higher compression ratio of a diesel will reduce exhaust temps, but the rich mixture of a petrol turbo should lower temps.
It would probally require two 2l diesel turbos to power a 3l petrol engine.

Darren

First of all, twins are pointless. Find a single turbo to suit your application.

With ref to temps, variable vane geometry is generally accepted not to stand u to the heat. Its not CR and mix related, diesel just burns cooler than petrol be a couple of hundred degrees.

I looked at it because the most suitable turbo for what i wanted (160bhp) tended to only be available on diesels. If youre fitting to a 3l, why would you want to use one? use one of the many commonly available petrol turbos in that size range!

Turbos are rated by efficiency, limited on flow and pressure. a bigger engine will consume more air and therefore the pressure will drop at high rpm if the turbo cannot flow enough to meet demand (this is how most OE engines are setup) a bigger turbo (selected correctly) will make more boost high up and if correctly controlled a more linear torque curve

I am planning on a sequential setup as I really hate lag, my 2l turbo just is too slow until it gets going, thinking that a diesel turbo will give me boost quicker through the lower reve range.

As far as temps go burning 1 mole of diesel will produce a similar amount of power as 1 mole of petrol, so the difference in heat must be the thermal efficiency of the engine. As the compression ratio is higher, more energy is absorbed from the gas before being released.

Darren

quote:

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Originally posted by turbodisplay
As far as temps go burning 1 mole of diesel will produce a similar amount of power as 1 mole of petrol, so the difference in heat must be the thermal efficiency of the engine. As the compression ratio is higher, more energy is absorbed from the gas before being released.

Darren

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At full throttle isn`t the lambda ratio about 1? I`ve seen some chipped diesels that pour smoke when the throttle is opened. Also seens a narrrowband lambda sensor on a diesel also pointing to lambda 1 being used at some point in the cycle.

Darren