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Discussion Starter #1
running a sbf 10-1 compression 88mm turbo a/w intercooler on c16

i think i had a spark blowout stumble going down track
couldnt really find anything wrong but got to thinking
maybe the plug is too cold

intake air temps start at 85 at start of run and down to 65 by end of run

had a stutter from the burnout box all the way to the traps

holley waste spark coils with msd wires
ngk r5671a_10 plugs
 

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That is a cold plug but shouldn't be your issue. What are you using for cam and crank sensors? Have you done a system log to verify that you aren't losing signal?
 

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Discussion Starter #3
yeah i did do a system log and didnt see anything dropping either signal
its not very violent of a miss
just one cylinder or so

any suggestion on a gap for that cold of a plug
 

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yeah i did do a system log and didnt see anything dropping either signal
its not very violent of a miss
just one cylinder or so

any suggestion on a gap for that cold of a plug
How much boost you running and a cold plug is better then a hole in a piston :p . What the plugs look like ? I'm guessing you need more timing
 

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yeah i did do a system log and didnt see anything dropping either signal
its not very violent of a miss
just one cylinder or so

any suggestion on a gap for that cold of a plug
.018" or thereabout should be ok... bigger gaps require more power to jump a long distance... heat range is the ability of the plug to dissapate heat before next compression cycle so colder = faster plug cooling. Not cool enough can touch off preignition and damage pistons faster than you can realize something just went wrong!

Try your gap first... go one step hotter if gap change didnt help and be sure you read your plugs right. avoid going too hot.

This guide may be useful if you're on the dyno or have time/space to pull over at test tune at the track... http://www.wallaceracing.com/plug-reading-lm.html

btw keep the simple stuff in mind like wire routing, chaffed wires and poor connections. And things as simple to fix as a poor crimp at an altenator connection can drive you nuts till you find it.
 

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Discussion Starter #7
Thanks man I appreciate it
One thing I noticed
I have msd wires and two of them weren't very difficult to pull off like the rest of them
I could hear them click but little less than the rest
I hate these multi boots from msd
Anyone have any feedback on moroso 40s ?
I'll drop the gap down to 18 before next time I take the car out
I wasted the supposed pro mod trans I have so now that's sucking up all my money at the moment
 

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Definitely drop gap down to .016-.018" wide gaps do not make more power and only cause problems. I would also recommend buying a quality plug gapper that uses a feeler gauge to set gap and squares up the ground strap in relation to the electrode.
 

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Discussion Starter #11
No oil in cylinders
I'll drop the gap and have to locate a good plug gapper
Now I just use a feeler gauge

Also
Does anyone know if moroso boots are a little easier to deal with then those msd multi angle
 

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If you use some silicone grease in the end of each boot they will be way easier to deal with. Snyder Motorsports sells a gap per like I use but be warned they are a bit pricey. You get what you pay for though. You may shop around and find one cheaper but at least you will know what you are looking for. Hope this helps.
 

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It was low on timing like 22 degrees and only 16 psi of boost
its not that low on timing, depending on the cylinder head chamber and piston shape etc etc etc.

Could be overly rich or the plug may be cracked.
 

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I would use q16 and turn timing up. That 10 plug is too cold for that boost level and motor probably lean if reading plug. Of coarse we don't know rest of motor or type of 88 turbo. I would use fire core wires those msd suck you could ohm the wires
 

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I would use q16 and turn timing up. That 10 plug is too cold for that boost level and motor probably lean if reading plug. Of coarse we don't know rest of motor or type of 88 turbo. I would use fire core wires those msd suck you could ohm the wires
You know absolutely nothing about how his engine behaves, inductive lag, chamber efficiency etc, don't go making that recomendation.

I have a fried with a SBF that makes gonzo power, with 16 degrees at 20 psi of boost.

don't assume what works for one engine will always work for another engine.
 

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You know absolutely nothing about how his engine behaves, inductive lag, chamber efficiency etc, don't go making that recomendation.

I have a fried with a SBF that makes gonzo power, with 16 degrees at 20 psi of boost.

don't assume what works for one engine will always work for another engine.
I said we need motor info but any sbf on that fuel at that boost 16 degrees timing way too low up top. Rpm would be a factor but you can run Damn near n/a timing on boosted motor depending on fuel resistance. Too many motors are under timed and too cold of a plug fact.
 

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I said we need motor info but any sbf on that fuel at that boost 16 degrees timing way too low up top. Rpm would be a factor but you can run Damn near n/a timing on boosted motor depending on fuel resistance. Too many motors are under timed and too cold of a plug fact.
Please don't give people tuning advice
 

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I would use q16 and turn timing up. That 10 plug is too cold for that boost level and motor probably lean if reading plug. Of coarse we don't know rest of motor or type of 88 turbo. I would use fire core wires those msd suck you could ohm the wires
Why in the hell would you send him off to a more oxygenated fuel, espeacially if there is a chance he may be running a tid lean???? "Gee run a hotter plug, more timing and more oxygen in the fuel bet it lights" that is piss poor advise and is an invite to a burndown...

Have any of us read his sparkplugs properly???

His issue sounds likely his plug gap is too wide... 10:1 compression and 16 lbs boost is a good amount of cylinder pressure. If not could be other ignition related issue... Wide gaps dont help... decreasing gap to .016-.018 often solves his type issue. BESIDES plug readings are the only way to ascertain if indeed mixture is off or if plug is too cold...

Unless you think fuel is contaminated you DONT change fuel to solve a missfire issue. Let alone change the fuel type!!!

C15 is formulated FOR boost apps... Q16 can work, but I wouldnt advise changing and tuning to it until problems are sorted on the c15
 

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Discussion Starter #20
sorry for delay on answering some of these questions, went to the pdra race yesterday to spectate since my trans is still apart

any ill try to catch up

the motor is 392 cubic inch sbf
diamond pistons at 4.076 bore
tfs-r heads cnc ported 60 cc chambers
the turbo is from chris at crt it is his dual 6 blade billet wheeled 88mm based off of the garret gt55

as for changing fuel thats not gonna happen i got alot of c16 and im not gonna switch to something that is not very friendly to sitting around

as for rotor phase im using a price motorsports cam sync set at 185 degrees btdc in accordance with the holley instructions
the crank trigger is set at 60 degrees before tdc and i have verified timing at idle and 3000 rpm with no need for a change on inductive delay

the plug gap is actually at .022 and ill attach some pics of the plugs

the car also seems to take a good bit of time to start up while cold which i was kinda attributing to the cold plugs

i have a few sets of plugs and its not a big deal to sway out to a hotter heat range
does the consensus say to drop one or two heat ranges ?

as for the wires my only gripe with them is the stupid multi angle boots and how much of a pain in the ass they are to get onto the plug and how ya cant really tell if they are all the way clicked on
are the firecore wires any better for this ?
it takes longer to put the plug wires back on then it does to change out all the plugs and gap em

heres some pics of three plugs
they all look like this




 
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