tuning after NA to turbo conversion

[barryogen]

Can anyone tell me why cars aren't tuned on 91 octane gas after a turbo upgrade to a NA car?

wouldn't it make sense to do it that way(increased engine safety)?

I can see why tuning it for use on 98 would be good for getting better numbers, but with the dodgy gas that we get here, surely tuning for 91 would be a much safer option.

anyway, if someone can tell me, do it.

[Ae92typeX]

off the top of my head,more chance of detonation, unless you retard more, thus loosing power.

[Mr Revhead]

well on an N/A car youv got higher compresion so youll need the higher octane for starters........

its just as safe as tuning for 98..... a bad tuner can still kill it on 91.
so why not go for what is effectivly free horsepower? (other than the higher fuel cost)

you could tune it for 91, i imagine on some applictaions that will be a challenge.... but seeing as the aim of a turbo conversion is power.....

[barryogen]

[quote="Mr Revhead"]well on an N/A car youv got higher compresion so youll need the higher octane for starters........

its just as safe as tuning for 98..... a bad tuner can still kill it on 91.[quote]

sorry, I wasn't very clear, what I meant was tune for 91, and tell the owner to use 98, giving a 7 octane buffer to cut down the chances of killing it with too much boost(everyone gets boost happy at some point ).

[Punter]

So you think it would be good to detune a engine after a turbo conversion, If a car is tuned/built properly it won't just exploed randomly.

Why is less power good?

[barryogen]

Why is less power good?

usually safer if sitting on the edge.

either way I think I have had my question answered.
you could, but why, and it's not much safer if at all(although I thought bad gas{lower octane than meant to} has killed engines in the past).

[Ako]

Tuning for 91 would be like training for a marathon by going for a jog round the block. Why bother going through all the effort of going to a turbocharged setup, then crippling it by making it run on crap gas?

And if you get happy with the boost and crank it through the roof - AFTER having the car tuned at a certain level, of course its going to die eventually, even if you were running c16 you're going past what has already been deemed a safe tune.

[barryogen]

ok then, I think I get it.

so basically as long as the gas is always whatever it was tuned for you'll be fine.

So do people just hope to never hit a bad batch of gas?

[Ako]

In a nutshell, yep. A proper street tune shouldn't be right on the very edge of safety though, tends to be only race cars which run that close - mainly cause they can be assured that each batch of gas they use is the same, even then they still put in a degree of safeguard.

There's always a buffer... Or at least should be. If 1 or 2 octane points is the difference between a good engine and a dead one, the car shouldn't really be road driven.

[CozmoNz]

just ask for a very safe tune, with no amazingly large amounts of advance, and the tuner should do something within his margin for "very safe"