New Honda GX160 T2 ignition coils - apparently a bit faster???....

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knighty

Member
Over here in the UK there is a new Honda GX160 ignition coil being fitted as standard, which is apparently "a bit faster".....personally I'm highly suspicious this is BS, but I was just curious if you guys in the US have noticed anything? and might possibly understand why its supposedly faster?

Please consider our engines are highly regulated, the ignition timing is checked regularly at post-race scrutineering, as is the maximum compression ratio, plus lots of other bits when heads and side plates are removed. My point being I dont think it changes the ignition timing.

I'm guessing its perhaps an electromagnetic change in the lamination's and magnets, therefore perhaps provides a more juicy spark?......any ideas welcome......
 
We don't think the spark is more enhanced, but we do see a different timing curve vs rpm. The new UT2 coils do not retard as much as the rpm is increased. Consider also that the coil legs to flywheel air gap have an influence on the timing curve and HP.

Steve
www.Bakerracingengines.com
 
Many thanks, now thats very interesting, so no change to the static ignition timing, but the dynamic timing remains advanced at higher rpm - trick......am I allowed to ask what this does to a typical power or torque curve.....from what you say I'm guessing its more relevant to the 5000-6000 and higher rpm region?......my point being are we talking 0.1hp or 0.5hp gain?
 
your advice is really appreciated......is there perhaps any guide or rule on air gap?........I will completely understand if you dont want to comment!
 
Some air gap data we generated a few years ago you might find interesting. As you can see from the timing curve the timing retards at elevated revs when using small air gaps.


Steve
www.Bakerracingengines.com
 

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Wow....this is really interesting, I will check all my T2 engines and see where they fit on your data......my deepest thanks for being so open and helpful.
 
Have you ever calculated these curves by percentage. Except for the numbers, the curves look very similar.

What's your theory on the timing advancing with a wider gap?

On the face of it, I would think just the opposite, but I guess I'd be wrong.
 
steve baker said:
Some air gap data we generated a few years ago you might find interesting. As you can see from the timing curve the timing retards at elevated revs when using small air gaps.


Steve
www.Bakerracingengines.com
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Thanks for sharing that information it is indeed very interesting. However, I am struggling to understand why having a bigger air gap would actually have the effect of advancing the timing. Please note I am not challenging your finding I am just curious.

Would this apply to a GX200 UT2?
 
I have updated 2 of my Gx160 T2 engines with the new T2 ignition coil and sure enough I can see a bit more power at higher revs, about 1/4 to 1/2hp more between 5-6000rpm, whereby before the power fell off a bit more noticeably......but I have since seen dyno plots of engines from the same race series on the same dyno, with much more power at the top end, and the peak power is made at about 5200rpm, whereby mine is at 4500-4800rpm.....my ICL for the 2 engines (standard cam) in question are set at 112 and 114Deg, and it seems the engine with 114Deg responded a bit better than the 112Deg motor......would I be right in thinking that the new coil, with more ignition advance offered at higher revs (from the new coil + bigger gap) will work with a higher ICL figure???......I'm thinking 116Deg is worth a try........any opinions would be appreciated.
 
knighty said:
I have updated 2 of my Gx160 T2 engines with the new T2 ignition coil and sure enough I can see a bit more power at higher revs, about 1/4 to 1/2hp more between 5-6000rpm, whereby before the power fell off a bit more noticeably.
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Just a query; do you/they employ an EGT on the dyno?
 
nope, but I could sure rig one up by having a thermocouple boss welded to the neck before the exhausts silencer box entry of a standard GX160 exhaust......what trends would I be looking for?......hotter or cooler = what?......you have got me thinking for sure!

My only experience of EGT's is on multiple cylinder engines where we were checking to see differences associated with air distribution in the inlet chamber due to a side feed system on an I4 engine.......so for a single cylinder engine I hadnt given it a thought......but your query intrigues me!......I'm all ears
 
knighty said:
nope, but I could sure rig one up by having a thermocouple boss welded to the neck before the exhausts silencer box entry of a standard GX160 exhaust......what trends would I be looking for?......hotter or cooler = what?......you have got me thinking for sure!

My only experience of EGT's is on multiple cylinder engines where we were checking to see differences associated with air distribution in the inlet chamber due to a side feed system on an I4 engine.......so for a single cylinder engine I hadnt given it a thought......but your query intrigues me!......I'm all ears
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Not sure what you're talking about, the gauges I've used, Digitron, had a probe that went into the exhaust header just after the port opening. About 3 1/2 inches from the piston face. The tip of the probe was positioned in the middle of the flow. The position doesn't really matter unless you want to compare your readings to someone else. In that case, you would want your probe positioned pretty much the same place as theirs. I'm pretty sure the data is gathered at the tip of the probe, thus the reason for positioning it (the tip) in the center of the flow.
 
Here is your chance to show everyone what you know after telling us we should be doing this. The guy is asking what information he should gather to use to determine the condition of his tune.
 
No Worries I think i have worked it out after a bit of googling around, the EGT is used as a means of how lean or ritch the combustion charge is in the exhaust system

Hot temps = too much wasted energy going down the exhaust, which is an indication of poor valve or ignition timing = less power.
Cooler temps = less burn in the exhaust therefore more combustion pressure is producing work against the piston = more power.

Its a far simpler way of understanding the air-fuel ratio, opposed to using a lambda sensor

I found this article about EGT's which was particularly interesting:

On a petrol engine, the EGT will normally be hottest around stoichiometry and cooler either side of that. If we add fuel at stoichiometry (this is where the air/fuel mixture is approximately 14.7 times the mass of air to fuel. Any mixture less than 14.7 to 1 is considered to be ‘rich’, any more than 14.7 to 1 is a ‘lean’ mixture) then we cool off the EGT due to excess fuel. If we lean off from stoichiometry we cool down the EGT due to excess air. Spark advance also plays a large part in the temperatures seen at the exhaust.

When the spark advance is at its optimum position in the cycle, the mixture is fired nice and early on in the piston’s power stroke and the heat generated is used to propel the piston down. Much heat is also lost into the cylinder head’s water jacket. The later we start this process the less energy is used to produce power and heat the water, which means more of it is sent out into the exhaust. As far as the ignition system is concerned, less advance (more retard) = higher EGT. It’s also worth noting that rotary Wankel engines run higher EGTs than their more conventional crankshaft-driven counterparts due to their inherent thermal inefficiencies.
 
knighty said:
No Worries I think i have worked it out after a bit of googling around, the EGT is used as a means of how lean or ritch the combustion charge is in the exhaust system
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While this opening statement is, in some ways, close to correct, the rest of the article is totally wrong. The person who wrote the "inserted part" absolutely does not know the purpose of, or the use of, the EGT with a two cycle engine. I'm not sure, if he's talking about a four stroke, if he's even close there. I've never raced a four stroke with an EGT so I can't speak with any authority with that usage.
 
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