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Originally Posted by sleeper7
(Post 11467536)
Never said waste spark is absolutely junk. It's only bad if the trigger system is not accurate. And the FC is not as good as the FD. Waste spark does has it's place but when trying to make power, going sequential ignition is the best. There's a reason why most of the high HP cars are not running waste spark. And if they are there trigger set up is spot on. I have personally seen how far the FC timing can move around. It is crazy. If the senses is you have to have a split greater then 6 degs to prevent trailing firing before leading. is it the trailing of leading timing that is moving around???? Another thing to think about when making big power and waste spark, your sparking the waste spark just before the apex seal travels over the plug. if the plug does not cool in time it will ignite the incoming chamber. There is a reason why Mazda made the trailing plug hole so small. compression and eliminating as much fuel entering the plug area. There's more but.
10 14 years ago this guy was hurting motors on waste spark. E6#. FD. the only thing that help was to eliminate the waste spark. everything else was left alone. And he has one of the fastest FD in the country. Waste spark IMO is for fuel economy. And E85 does help with turbo spool. Seen it done it! |
Said IF they are running waste spark with big power. I cant say everyone is making power is running direct fire ignition. Have no idea what's out there. Know for sure everyone I've talked to and seen at the track is running direct fire ignition. Waste spark is past it's time.
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i don't much care for waste spark either but many people are stuck with it depending on their initial choice of ECU.
it's not just for gas mileage/emissions but it was also an effort to save cost when building the cars that the ECU manufacturers just adapted to, since it was there. ideally you have both plugs jumping gaps in the same direction versus one jumping plug chassis to electrode>electrode to chassis on the next. the mileage benefit is minimal for a high power car, you probably won't even notice its absence. but it still works, regardless. about 75% of my work is with FCs and out of hundreds of builds only 1 was almost strictly built for drag racing(and was also the most problematic build). the rest are all built for street driven applications and need reliable ignition for many many miles and i rarely run into blown engines from questionable ignition related issues. |
Originally Posted by driftxsequence
(Post 11467570)
Hmmm so it sounds like replacing the CAS is more beneficial than the coil setup.
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Interesting thread in the naturally aspirated section about coils. A few guy feel waste spark is holding them back at higher rpms.
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Originally Posted by sleeper7
(Post 11483554)
Interesting thread in the naturally aspirated section about coils. A few guy feel waste spark is holding them back at higher rpms.
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another thing about waste spark being bad, the waste spark fires so close to the on coming chamber that if the plug does not have enough time to "cool" it will ignite the on coming chamber. Higher rpm and hp creates more heat. With direct fire the plug has enough time to cool and the coil has enough time for a complete charge.
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sleeper 7 i seen a video of your car and what gas are you runing.
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E85
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another thing to think about when the waste spark happens. actual engine timing is not the same as the timing on the front pulley. So waste spark happens really close to or almost on top of the apex seal. And if the waste spark spark plug does not cool in time, it will ignite the on coming camber. Then add a little timing drift and your asking for trouble.
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IMO Waste spark should only be used for low boost application and for NA or higher boost levels direct fire all the way. What's the most HP reliably anyone ever seen on waste spark?
P.S I love the smell of E-85! I think if more turbo rotary cars were E-85 they would last longer. I blew one motor on E-85 but it was a timing issue but wont and don't blame it on the fuel but mechanical error instead. |
1 Attachment(s)
My engine popped an Apex seal last weekend while running a mixture of E85 / 93. Flexfuel sensor was seeing between 45-49% Ethanol in the mixture. I don't believe the failure was caused by the fuel, but more of a general wear and tear of a tired engine. Was just getting into tuning the AFR's for positive pressure before the seal popped. Did a good clean 3rd gear pull and once we made it back to cruising RPM under vacuum the seal had popped. Here's a pic of the log.
Attachment 663864 Was tuning to 198 kPa (just under 1 bar) |
"My engine popped an Apex seal last weekend"
do you have knock data? |
What seals?
Am I reading your log right? the afr in the mid 12s at max boost? I also hurt a motor when running 50/50. But the boost was allot higher then yours. |
Originally Posted by sleeper7
(Post 11483554)
Interesting thread in the naturally aspirated section about coils. A few guy feel waste spark is holding them back at higher rpms.
the simplest fix, is just to go direct fire, as you instantly get twice the charge time. however you could also run a more powerful coil, so that even if its not charged fully it can still ignite the plug, or you could increase the voltage, which will charge the coil faster. the important thing is to have enough ignition power, and it just happens that the stock FC coils are very powerful, so its cheap and easy to just direct fire them, vs finding some other solution. |
post your timing maps
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Originally Posted by sleeper7
(Post 11483726)
another thing about waste spark being bad, the waste spark fires so close to the on coming chamber that if the plug does not have enough time to "cool" it will ignite the on coming chamber. Higher rpm and hp creates more heat. With direct fire the plug has enough time to cool and the coil has enough time for a complete charge.
Virtually all of the heat in the spark plug comes from exposure to the combustion process or heat conducted from the block. The arc introduces so little heat into the plug that it is negligible; in the noise. I would not expect it to have any role in the scenario you've described above. (unless, of course, you're using a 1 kiloton ignitor :lol:) |
Originally Posted by Howard Coleman CPR
(Post 11550082)
"My engine popped an Apex seal last weekend"
do you have knock data?
Originally Posted by sleeper7
(Post 11550121)
What seals?
Am I reading your log right? the afr in the mid 12s at max boost? I also hurt a motor when running 50/50. But the boost was allot higher then yours.
Originally Posted by arghx
(Post 11550460)
post your timing maps
Here's a link to download the Link basemap with all the configs: https://docs.google.com/file/d/0BwlQ...it?usp=sharing and a link to the log: https://docs.google.com/file/d/0BwlQ...it?usp=sharing Other thing to mention is I was pre-mixing about 3/4 ounce per gallon using Klotz Benol. |
Don't let Pettit Racing hear all this shit......LOL
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Originally Posted by Speed of light
(Post 11550589)
Virtually all of the heat in the spark plug comes from exposure to the combustion process or heat conducted from the block. The arc introduces so little heat into the plug that it is negligible; in the noise. I would not expect it to have any role in the scenario you've described above. (unless, of course, you're using a 1 kiloton ignitor :lol:)
Your correct about the waste spark not producing allot of heat or energy. My question is how much heat in the spark plugs does it take to ignite the oncoming chamber as the seal passes over the leading plug? Very little. Compression is very low at this point the in the compression cycle and that make it the easiest time to ignite the chamber. |
hey chuck watched your videos car sound sick,
u gona make me drive to dragmania to see it run :) I have a set of rotor housings that are in great shape except the trailing plug hole its enlarged to 1/4 inch. Will that cause problem plug getting hotter and preigniting the afr mixture with direct fire ignition on e85? not sure if I should use them |
Wildman:
what's w your ignition angle? it shows 40 degrees and is probably not? maybe an offset? i don't see a problem w your AFRs. howard |
Originally Posted by howard coleman
(Post 11554471)
Wildman:
what's w your ignition angle? it shows 40 degrees and is probably not? maybe an offset? i don't see a problem w your AFRs. howard |
Originally Posted by RXTASY57
(Post 11467459)
Well, it looks like you can blow it up on E85, just takes a lot to do it!
Given the propensity of easily blowing up the rotary engine, I don't understand why more rotary enthusiast's don't use E85? I feel like it is the holy grail for our cars! |
I'd love to go E85....I feel like I'm just flipping a coin in terms of dealing with some of the maintenance that comes with it though. The last thing I want is an injector getting stuck open or filling up the tank only to find out it's still a winter blend.
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