[RobJ]

Hi,

I keep reading that you only get the true benefit of using higher octane fuels if your engine is tuned for them.

How much benefit will i see if i get my motor re-tuned for 95 octane fuel?

And what is involved in the re-tune itself?

[Rusho]

Just an advance in the timing I think? I'm sure someone will chime in and correct me if I'm wrong.

[want33s]

Retune is as simple as cranking up the timing a bit.
Adding good quality spark plugs will help too.
Benefits of higher octane fuel:
Easier starting.
More timing advance means more power is possible.
Better economy if driven sensibly. More power means you can short shift gears.

[31zook]

short shifting is awesome

also, if you time it forward you then shouldn't run normal fuel btw, not sure why just heard it.

[RobJ]

Is there a noticeable difference to top speed and/or acceleration? Is it worth the effort?

Also, if you run a lower octane fuel than your engine is tuned for you will get engine knocking i believe.

[Rusho]

RobJ wrote:

Is there a noticeable difference to top speed and/or acceleration? Is it worth the effort?

Also, if you run a lower octane fuel than your engine is tuned for you will get engine knocking i believe.

yes and possibly yes

[RobJ]

Do you know whether i will be better off doing it for 95 octane or should i consider 98.

I wouldn't imagine a 1.3lt '92 motor will be able to reap enough benefit from the difference between 98 and 95 to justify the price difference at the pumps will it?

[Rusho]

Personal preference. Mine loves the 98.

[31zook]

dead set to tune it for 95 or 98 is borrowing a timing light and undoing a nut then moving the dizzy across a pooftenith then tighten her up, a 1min job.

[Lokidog]

You may also find after doing the higher octane, newer plugs, adjusted timing etc… You fuel economy and power will progressively increase over time.

Also something else brought up in another thread…

want33s wrote:

:oops: Correction...
It says BP5ES on the sticker under bonnet but with unleaded and higher octane the BP6ES is the plug to use.

This explains the heat range thing....
http://www.ngksparkplugs.com/tech_suppo ... p?mode=nml

[burls]

What degrees should it be for 95 and 98?

[Ben_Sierra]

burls wrote:

What degrees should it be for 95 and 98?

As far as you can advance it without it pinging...

[Brett]

you can tune it to 95 but it wont make a difference you will feel, unless it is running really bad. you might get a extra 5 hp at the engine if your lucky.

just give it a good tune up. make sure you get the right plugs, the gaps are right and you leads are in good nic. then filters and a oil change in everything.

also make sure your carby is opening up all the way most carby cars i have worked on the carby hasn't opened all the way

[Brett]

o and for tuning for a higher ron fuel the dizzy spark curve should be changed. most people just turn the dizzy and end up with a car that is very doughy down low

[v.w.dave]

on 98 i get about 50ks more. I have found a noticable differance in the bush. On 98 it is more responsive and better on angles. I tuned mine on 95 but i made it 1 mark advanced. To do a good adjustment you really need to run it on a few tanks of 98 then adjust it.

[bakerboy]

why go to a cooler plug when you up the rating?

[Brett]

because it burns the fuel better. colder plugs take more comp before the tips burn out. but if your plug is to cold it can some times not fire under heavy load.

i'd only every go one maybe 2 steps colder on a na engine

[SuziBlu]

Can you explain this better please, I have never heard of it, nor can I begin to understand what you mean.
Colder plugs are just shorter.

I run 98 on my 1.3 and have the timing set at 13°

[Brett]

put it like this one or 2 steps colder in a plug with 98 wont do much, you would only do if if your after every little bit you can get after a very good tune. gaps sizes are nor important then heat range on a stock engine.

you normaly run a colder plug when you change a cam, shave a head, stroke or boost a engine and get more comp. when you have more comp you have more heat so you need a colder plug so you don't burn them out.

ooo and a colder plug has a higher number not lower as most people think.

[bakerboy]

no only ngk do that, bosch are a smaller number for cold, higher number for hot

[v.w.dave]

hahaaahaha you all do realise we are talking about a 1.slow suzuki engine that runs a relatively low compression that even the best tuning by the best suzuki tech and without doing anything internal at best you will get mabey if your lucky 10 extra hp. You are getting way over the top getting into spark plug temps. Its a fuck suzi put what fuel you can afford in it and drive.... Next thing you know you will be talking about the different atomization value of you piston tops. As is my same argument with oils, suzuki made and designed there motors using a certain plugs or oil and they spent a few $$$ on making them run with that plug why change. But i am sure you know more then the enganeers so do what you wish.

[want33s]

v.w.dave wrote:

hahaaahaha you all do realise we are talking about a 1.slow suzuki engine that runs a relatively low compression that even the best tuning by the best suzuki tech and without doing anything internal at best you will get mabey if your lucky 10 extra hp. You are getting way over the top getting into spark plug temps. Its a fuck suzi put what fuel you can afford in it and drive.... Next thing you know you will be talking about the different atomization value of you piston tops. As is my same argument with oils, suzuki made and designed there motors using a certain plugs or oil and they spent a few $$$ on making them run with that plug why change. But i am sure you know more then the enganeers so do what you wish.

Been drinking Dave?????
Suzuki designed and built the G13 almost 30 years ago..... Quite a bit has changed in fuel quality/blends as well as spark plug technology...
If you are happy to live with what the manufacturer said was good 30 years ago then good for you but most of us would like to take advantage of the improvements that have been made by upgrading plugs and timing specs...
If you can't add constructively... Don't.