306 Turbo Tuning - to increase fuel efficiency

Soldato
Joined
7 Aug 2004
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11,309
From this article:

http://www.club-306.com/guides/306_turbo_tuning

By using lower boost pressures you will get higher torque, which means quicker acceleration and better fuel economy.

How easy is this ? what sort of MPG increase would I see? Would running a lower pressure 'break' the engine vastly quicker?, would there be problems ?

I only ask as obviously cars leave the design board setup and specced for a certain way, and peoguet know a lot more about cars than mwah :D so would me ******* with it not really help things?

Logically I cant see how it would do anything 'wrong' as its running a lower pressure, thus less strain on the engine, thus in theory it should be fine and infact last longer.......bar the apparent increase in torque on the gear box (how does that work if its getting less air-->fuel ?), which wouldnt be ideal, but I wouldnt accelerate like a nutter, I drive like a grandad nowadays. As said I only have basic ideas of engines........ anything you car genious's could answer would be fantastic :)
 
The usual screw-mod/stage 1 tune on the 306 actually increases the boost, never heard of reducing it.

Not heard of improving the fuel economy either, it's more a matter of trying to make it "less bad" after tuning.
 
Don't meddle.

Messed about with my 205 1.8DT and it never ran the same again. Unless you really know what you're doing then go ahead but if you're unsure don't touch.
 
its worthwhile.

but ask on pug306.net, will get a far more useful responce than on here as...

1. they hate diesels

2. if it ain't german, gtfo

:p
 
How would lowering the boot increase torque

sounds like nonsense. If you want a decent mpg setting stick it back to standard as they run lean from the factory.
 
Please read the whole article in context, it does not say that lowering the boost from stock will give you more torque!

What it is saying is that you will get better torque by not going mad with raising the boost after increasing the fueling. Raising the boost substantially means the tiny turbo is not operating efficiency and is mostly heating up the air and providing more of a restriction to the exhaust.
 
Considering the same tiny turbo can take the engine from 90bhp to 130bhp with the right tune, bosch pump and decat exhaust it clearly has plenty of potential beyond heating the air
 
However, if they could find some way of getting that warmed air inside the car, it would be lovely :)
 
Considering the same tiny turbo can take the engine from 90bhp to 130bhp with the right tune, bosch pump and decat exhaust it clearly has plenty of potential beyond heating the air

The point being that turbo diesels run with plenty of excess air (i.e. effectively lean) from the factory, so you can get good power gains without touching the boost. I don't want to argue, but if you have raised the boost significantly I suggest you check inlet temperatures! The top mounted intercooler on the XUD is nearly as useful as a chocolate fireguard, so it doesn't take much extra boost pressure to starting seriously heating the air, at which point you are better off with lower boost.

Sorry for daring to suggest a "screw modded" 306 isn't the fastest thing on 4 wheels...
 
Sorry for daring to suggest a "screw modded" 306 isn't the fastest thing on 4 wheels...

I've never claimed it is, I've owned better cars.

However the 130bhp was done on the top mount. JAC who tunes these cars on Pug306.net will tell you the top mount isn't as bad as it's believed. It's like most other top mounts such as the scooby and Pulsar, once on the move they do work sufficiently.

Also I entirely agree, when I screw modded my car I didn't touch the waste gate arm at all. The boost went from 14 psi to 16.5 just simply as a result of the extra fuel. There really is no need to increase the boost pressure further :)
 
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