Audi A8 D4 4.2L FSI V8 retrofits

Architex_mA8tey · #1 26th November 2020, 11:55 AM

Am I right in thinking that the LPG conversion is different for FSi?

I understood that there are several important reasons why normal sequential gas injection systems are not suitable. Initially, the petrol injector nozzles will clog & overheat if not used, while running on gas.

I was led to believe that you need a system that will dual-fuel both petrol and lpg simultaneously, so the system runs 75% lpg and 25% unleaded.

Good work so far on it all, enjoying this thread!

steamship · #2 26th November 2020, 02:10 PM

Quote:

Originally Posted by Architex_mA8tey

I was led to believe that you need a system that will dual-fuel both petrol and lpg simultaneously, so the system runs 75% lpg and 25% unleaded.

That's what I was told when making enquiries about the FSi engines. The petrol injected is used to cool the fuel injectors to stop them being fried.

An interesting build this especially with the LPG, so intrigued to see the work to fit the LPG injectors.

v8quattro42 · #3 26th November 2020, 03:42 PM

Quote:

Originally Posted by Architex_mA8tey

Am I right in thinking that the LPG conversion is different for FSi?

I understood that there are several important reasons why normal sequential gas injection systems are not suitable. Initially, the petrol injector nozzles will clog & overheat if not used, while running on gas.

I was led to believe that you need a system that will dual-fuel both petrol and lpg simultaneously, so the system runs 75% lpg and 25% unleaded.

Good work so far on it all, enjoying this thread!

Yes you right.

There is two different lpg system on a market I know

One is Prins
Secound is Stag

Prins lpg installation cost €2500 and you running on lpg only using modify high pressure pump it’s supply for lpg and using petrol Injectors

Very difficult to have software to set up everything together

Stag cost me at this stage £700-£750 and I s likes standard sequential lpg system using separate injectors.
As you said it’s mix lpg and a petrol to cool down injectors nozzles but is not mix together both fuels. Is for 10 cycles using 7 times lpg and 3 times petrol that’s how it works.

I did use stag before on my A6 V8, v-class V6 and others. Never have any problems. Once I fit I already forgot I have lpg on my cars.
Never replace any parts after fitting and I did lots of miles. Just filters and fill up that’s all.

I have enough equipment to program lpg ecu than I’m not worry about that.

Then as you see it’s to big difference between both system to think about this expensive option. Even if I gonna spend total for parts £1k still it’s better for m STAG.

v8quattro42 · #4 26th November 2020, 03:48 PM

Few photos from today. I’m very close to fill up a lpg tank maybe I will do that tomorrow. We will se how much I can fill up. I think it will be around 50l, space for a lpg tank it’s not massive I’m afraid