156 tuning and knock sensor

Hi folks

I have been looking to get some better performance from my 156 having got rid of the 3ltr GTV. I don't have lots of cash to spend on mods however. A friend has advised me to avoid a 10-15 bhp chip mod cos' he seems to think I won't actually get 10-15 bhp; he thinks I will probably only get 5 bhp at best. He did suggest the chip with a new cam although that is getting a bit more expensive. So i guess first up, can I gather some opinions on my options? Also, does anyone know if a 2002 156 ts is fitted with knock sensors? Looking to run her on V-power... My friend reckons this is going to be the cheapest way for me to make improvements to performance. Also, any thoughts on "Sprint Booster"? Thanks all in advance.

what do you mean by a chip? a remap? you will only get approx 5bhp, and not a lot of difference in performance.

cams cost a lot, but they do make a difference, to get the most from them you really need a different exhaut and intake and them a custom made remap. total cost well over a grand, but you'll knock a second off your 0-60 time.

you have knock sensors but your ecu strategy can only adapt up to 95ron so there is no benefit to running on v power or any other higher octane fuel. this is explained on the shell website. you must have fully adaptive ignition timing (or an ecu map designed for higher octane such as any jap import) to take advantage.

sprint booster is a con, but you knew that already.



best thing to do is get a cat back exhaust (powerflow are cheap), a GSR silicone intake (or make your own), and an ecu remap (£250). combined that'll make a noticable difference without costing the earth.

or even better fit the gearbox from a 1.6TS, then you'll fly without any other mods!

or even better better, do both.

Sorry, you're right I meant remap. I saw that autodelta did a cam and remap for £950 or thereabouts. This and a new air intake and cat back exhaust is the way forward then? I gather then from your comments that the remap would then enable me to take advantage of the high octane cos I would then have advanced ignition?

I would change to a v6 or gta if my mrs would let me but she has poo-pooed that idea the moment I said about. If I make the changes to the current car she might not notice the changes and the money I am pouring into it! Hurrah!

Originally Posted by horseman

I gather then from your comments that the remap would then enable me to take advantage of the high octane cos I would then have advanced ignition?

it depends. all the prewritten maps are designed for 95RON. a 97 or 98 RON map would need to be custom made (even more advanced ignition timing) which costs more. i know people who have done it (even on crappy 1.2l cars wtf?!) and tbh the difference isnt noticable, a regular £250 remap will be just as good.

personally i wouldnt want to have a map that requires the higher octane, it means any time you use a regular 95RON fuel you will have almost constant pinking, which reduces performance significantly and causes damage as shown by the death of jap imports with foolish owners trying to save a few quid. the ecu will constantly try to advance ignition back to 98ron timing, but detect pinking before that happens and retard it again, and on it goes.

the price of fuel is going up and up, do you really want to be forced to use super unleaded all the time?

Originally Posted by jug

you have knock sensors but your ecu strategy can only adapt up to 95ron ...

It is actually a minimum of 95RON, not maximum.

Originally Posted by David C

It is actually a minimum of 95RON, not maximum.

trust me it definately isnt.

if it was min 95 ron explain how the car can still run on poor quality fuels with a lower octane without suffering from pinking?

the whole point is that the engine can run on lower octane fuels by retarding the ignition timing below the 95ron timing, but it cant advance it higher than 95 ron unless it is "fully adaptive", and the 156 isnt.

check the shell website, it tells you the facts. there is no point using higher than 95ron on our cars.

Originally Posted by David C

It is actually a minimum of 95RON, not maximum.

Originally Posted by jug

trust me it definately isnt.

From page 192 of my 156 manual:
"Unleaded petrol with an octane number (RON) above 95"

Originally Posted by David C

From page 192 of my 156 manual:
"Unleaded petrol with an octane number (RON) above 95"

exactly, thats the proof right there!

that is the recommend fuel to prevent pinking, obviously anything below 95ron will cause pinking, so the ecu must be set for 95ron. if it was able to adapt higher than 95ron the manual would recommend a higher ron to prevent pinking, not 95ron.

Originally Posted by jug

trust me it definately isnt.

if it was min 95 ron explain how the car can still run on poor quality fuels with a lower octane without suffering from pinking?

the whole point is that the engine can run on lower octane fuels by retarding the ignition timing below the 95ron timing, but it cant advance it higher than 95 ron unless it is "fully adaptive", and the 156 isnt.

check the shell website, it tells you the facts. there is no point using higher than 95ron on our cars.

Originally Posted by jug

exactly, thats the proof right there!

that is the recommend fuel to prevent pinking, obviously anything below 95ron will cause pinking, so the ecu must be set for 95ron. if it was able to adapt higher than 95ron the manual would recommend a higher ron to prevent pinking, not 95ron.

You seam to have contradicted yourself there...!

i cant see a contradiction in those 2 quotes, they agree with each other.

i think you're getting confused about adaptive ignition advance.

Originally Posted by jug

i cant see a contradiction.

Read closer:

Originally Posted by jug

if it was min 95 ron explain how the car can still run on poor quality fuels with a lower octane without suffering from pinking?

Originally Posted by jug

that is the recommend fuel to prevent pinking, obviously anything below 95ron will cause pinking,

if you read closer you'll see in the first quote i was asking you an impossible question as a way of showing you that you were thinking about it backwards. i guess you missed that. i hoped you'd try to answer it to yourslef, and then see for yourself that you were wrong without me telling you.

the answer to the impossible question is of course that the ignition timing adapts below 95ron, not above it, and that is why pinking wil not occur beow 95ron. it wouldnt occur above 95ron natually so there is no need to adapt.

use lower than 95ron and pinking will occur. that triggers the knock sensor, which causes ignition timing to be retarded, which stops the pinking. adaptive ignition timing really is that simple.

Another point worth remembering:
Normal Unleaded Petrol: EN228 RON min 95 max 100
Super Unleaded Petrol: BS7800 RON min 97 max 100


So you could have a random sample of "normal" unleaded that has a higher octane than a random sample of Super Unleaded.