Suzuki GSX-R Motorcycle Forums Gixxer.com banner

1 - 10 of 10 Posts

·
Registered
Joined
·
52 Posts
Discussion Starter #1
Hi Guys
Recently browsed through the tips and tricks section and saw how to make your own ignition advancer.
Two questions if any of you learned gentlemen would be so kind.

1. I am at altitude +-1400 metres above sea level, does that affect the ignition timing,and how (dont you need to retard instead of advance)??
2. The guy in the article says its located under the right hand engine cover, is that the right hand side when sitting on the bike?
Thanx
Joe
 

·
YAAFM Mod
Joined
·
3,016 Posts
Yes its as you sit on the bike. As for retard or advance it should be advanced but as I do not run a stock Ign system (Dyna 2000) I would not know how far to advance you stock system.
Bones
 

·
Registered
Joined
·
3,895 Posts
I'm basically at sea-level, and I have individual filters, jet-kit, and a Hindle 4-2-1 pipe, and 3-4 degrees gave me the best numbers on the Dyno. 5 degrees was too much (although I usually use 87 octane, so I could prolly get away with it if I stopped being a cheapskate and used the 92 octane stuff). I honestly have no idea how altitude affects timing, but I *know* that the air isn't as dense up there so it *does* affect jetting. The way I understand it is that you should run as much advance as you can without pinging or pre-ignition.
 

·
Registered
Joined
·
52 Posts
Discussion Starter #4
Thanx all

Does anybody know if 38 mm Mikuni flatslides is a good choice for our bikes (only got a pipe motor otherwise standard)
 

·
Registered
Joined
·
3,895 Posts
Originally posted by TheHun:
Thanx all

Does anybody know if 38 mm Mikuni flatslides is a good choice for our bikes (only got a pipe motor otherwise standard)
<font size="2" face="Verdana, Arial">I dunno `bout the 38's... I'm getting 131HP and 84 ft-lbs out of mine with the 36's, paired filters, and Hindle 4-2-1.
 

·
Registered
Joined
·
17,099 Posts
Originally posted by FastCat:
The way I understand it is that you should run as much advance as you can without pinging or pre-ignition.
<font size="2" face="Verdana, Arial">you can lose power advancing the ignition too much even if you don't get detonation.....if peak combustion pressure occurs as the piston is still rising, energy is wasted as combustion works against the engine. in the end, you lose torque (and thus horsepower).

so it's not about how much you should advance ignition timing to get maximum power, it's about how to time ignition events to get maximum power.
 

·
Registered
Joined
·
3,895 Posts
Originally posted by jeff:
you can lose power advancing the ignition too much even if you don't get detonation.....if peak combustion pressure occurs as the piston is still rising, energy is wasted as combustion works against the engine. in the end, you lose torque (and thus horsepower).

so it's not about how much you should advance ignition timing to get maximum power, it's about how to time ignition events to get maximum power.
<font size="2" face="Verdana, Arial">...makes sense to me... I never did *hear* any pinging on the dyno, (inside a building, and wearing earmuffs) but the best numbers I got were at +3 and +4... I just assumed that "pinging" was what was stealing power when we went to +5. I'm certainly no "pro" when it comes to tuning; I was under the impression that going to higher octane fuel slows down the speed of the flame inside the combustion chamber, and thus allows more advance... since this is a streetbike, and I'm gonna be running 87 octane in it, that's the way I tuned it on the dyno.

So if I understand you correctly, going to higher octane fuel won't necessarily allow more power to be gained from additional advance? I'm happy with the way everything's working for me, I just like discussing (and learning) all the nitty-gritty about what happens inside the engine... I'm kinda a nerd that way.
 

·
Registered
Joined
·
448 Posts
Originally posted by FastCat:
So if I understand you correctly, going to higher octane fuel won't necessarily allow more power to be gained from additional advance? I'm happy with the way everything's working for me, I just like discussing (and learning) all the nitty-gritty about what happens inside the engine... I'm kinda a nerd that way.
<font size="2" face="Verdana, Arial">A higher octane will allow more timing, but more timing does not always mean more power. Only a dyno will tell you how much of a gain you are really recieving if you run higher octane/more timing.
 

·
Registered
Joined
·
17,099 Posts
Originally posted by FastCat:
makes sense to me... I never did *hear* any pinging on the dyno, (inside a building, and wearing earmuffs) but the best numbers I got were at +3 and +4... I just assumed that "pinging" was what was stealing power when we went to +5. I'm certainly no "pro" when it comes to tuning; I was under the impression that going to higher octane fuel slows down the speed of the flame inside the combustion chamber, and thus allows more advance... since this is a streetbike, and I'm gonna be running 87 octane in it, that's the way I tuned it on the dyno.
<font size="2" face="Verdana, Arial">the problem is, detonation is not always easily audible, so the power loss may or may not have been attributed to detonation....



So if I understand you correctly, going to higher octane fuel won't necessarily allow more power to be gained from additional advance?
<font size="2" face="Verdana, Arial">correct....if we were to, say, run 130 octane fuel that would allow us to advance ignition timing 20 degrees (just pulling random numbers out), this doesn't mean that doing it would give us maximum power. power would likely drop well before that point even if there is no detonation.

the older oil cooled gsxr's do seem to have an ignition advance sweet spot around 4 or 5 degrees, although i'm not sure i'd want to run that with 87 octane fuel.

for whatever it's worth, i had a vance & hines power pak on my old '86 that had a selectable 'dragrace' ignition timing curve that was +7 or +8 across the entire rpm range. the instructions specifically warned that this was not suitable for street use and was meant only for short runs. apparently they were right.
i tried running this curve once and fouled the plugs after about 5-10 minutes of street riding.



I'm happy with the way everything's working for me, I just like discussing (and learning) all the nitty-gritty about what happens inside the engine... I'm kinda a nerd that way.
<font size="2" face="Verdana, Arial">there are a lot of factors that come into play for 'optimum' ignition timing......factory's got some interesting info on the subject:

http://www.factorypro.com/Prod_Pages/rtrhon804.html

http://www.factorypro.com/tech/ignition_timing_tech.html

[ 04-26-2002, 12:25 PM: Message edited by: jeff ]
 

·
Registered
Joined
·
52 Posts
Discussion Starter #10
Thanx all
Jeff, addressing the altitude question, it would seem to me that you should be able to use more advance than at sea level, coz you have poorer combustion at altitude??? How about the "38's", anyone using them?? I'm not a motor engineer,so please pardon some of the dumbass questions.
 
1 - 10 of 10 Posts
Top