90TT 80000Km 14Psi

Is it just me or do all of u get between 10-12MPG. No matter how I drive it,Does running it @ 14Psi make a great difference in Mpg, or is there something failing apart from the coolant sensor.

I have also got a 4.9L 928S4 Which I get 18-22Mpg, Someone must know the secret to driving a Zed economically..

Yeah....running at higher boost will definitely affect your mpg....yours does seem bloody low though (mpg, not boost!!).

 

Have a look at the general forum...there was a recent thread on 'expected mpg'.....I run a 1990 UK Auto TT......standard turbos, mongoose type cats back exhaust and K&N filter.....I usually get around 18-22.

i get about 22mpg running 1 bar boost. 12mpg is looow. If you drive the car real hard you can get that figure. Check for fuel leaks/smells. Check your maths. A "Which Car" report in 1990 when the cars came out over here got a 12 mpg figure in their test. But i would say there's a problem. Try driving the car a lot easier for a while and see if the mpg improves. if not there's a problem somewhere? Has it been chipped? That might cuase the problem if it's not done properly.

Sounds similar spec to mine, and similar performance. I'm finding that if I'm a bit leadfooted around town (meaning non motorway stuff) I'll get this, with slightly more if I'm really gentle (not worth it though!).

 

By contrast if I put it on a motorway and cruise between 100 / 120 it's superb - almost doubling the mpg.

 

The reason your Porch is better is because it's normally aspirated / high compression. By definition turbo cars are crap at economy cos they are either running low compression (off boast), or at 1 bar they are effectively using twice the air (so you you should be doing the math on a 6L engine.

 

Is it worth the expense though?

By definition turbo cars are crap at economy cos they are either running low compression (off boast), or at 1 bar they are effectively using twice the air (so you you should be doing the math on a 6L engine.

 

not strictly true, anything that raises the volumectric efficiency of an engine will to a certain extent, help fuel consumtion.

 

forced induction enables the cylinder to quickly fill with air, compressing it to give a high oxygen content to allow an efficient burn. hence the extra power.

 

the down side is, the more you boot it, the more air goes in & more fuel with it!!

 

 

 

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I feel the need, the need for speed!