Pleeaaasssseeee sticky this. Great information .

 

So would it be safe to assume that a 13B making 350-400 whp would benefit from the Autolite "X" plugs in that they increase heat transfer taking heat away from the plug area?

 

"So would it be safe to assume that a 13B making 350-400 whp would benefit from the Autolite "X" plugs in that they increase heat transfer taking heat away from the plug area?"

yes.

other Autolite options are the traditional, gappable ground strap AR3932 and a step warmer similar plug w a resistor... AR3923.

and of course there are other large ground strap NGK options.

i am going w Autolite.

howard

 

Looks like I'm going with the AR3923 as a starting point. I may just order the "X" versions anyways and see what kind of differences I can feel. You can never have enough plugs laying around.



Edit: Oh I forgot, what about the trailing? Are we just using these in the leading only or both?

 

Rotary Gospel, Preach.

 

yesterday we ran 205 MPH on the dyno w the AR3932 plugs.

no plug issues at 8650 RPM in 5th gear at 26 PSI.



howard

 

Howard, I am interested to know how your EGT trends on your pull through all the gears at WOT all the way to 5th gear at 8600 RPM. Does it level out,or continue to rise? If it continues to rise as mine does at WOT, what was your top number after that long duration pull?

 

you can see his EGT right there on the bottom graph, looks like a high of 1500 F at the 6000 rpm lean spot, down to 1350 F for the rest pf the pull until the end where it creeps a little to 1400F

 

I saw that, but I am not sure I am understang it since is below 1500F . Kind of figured it would be much higher than 1500F after a continuous 1st gear to 5th gear pull at WOT. Perhaps it was only a 5th gear pull and not a pull through all the gears.

 

here's your answer, 2nd thru 5th to 186 mph



part of what we did yesterday was enable the gear based features of the V88.

the motor will blow the tires off in 1st, second and almost all of third around 25 psi.

Luke lowered the boost in the shorter gears...

second is 20.4 psi and top egt is 1553

third is the same boost and top egt was 1613

4th is 24.6 and was 1618

5th is less boost 23.2 1505 egt w rich AFRs as it is for 3/4 of a mile. rich AFRs lowered EGTs

so EGTs did not cumulate.

BTW, just bought some additional 3932s at NAPA for $3.49 each....

howard

 

Cheers!!

 

I'm not sure if I missed your reply or not but, are you running these plugs in both leading and trailing?

 

sorry i missed you t-von.

i am running them in all four holes.

 

Picked up a set this weekend since my greddy plugs decided they had enough of my pump+water injection setup (23 pulls on the dyno + 5k miles). They are smooooth. No hiccups, loss of power or any other indication of problems. Clear up to 8200rpm @ 22psi on my t04z setup. This is running the stock coils with a twin power.

 

After reading what you wrote about the knock headphones...What are your thoughts about something like this? I am overly concerned about blowing my fresh motor while tuning it myself.

Could we utilize the factory knock sensor, and use this kind of system to detect knock?

 

I just purchased a set , and I'm curious what Gap are you running if you dont mind me asking , since its an FD , I have no idea what to use as a reference for the gap LOL

 

i do think the gap setting is something that should be determined by the setup and application.

we set our gap at .02 so as to discourage exterior (under the boot to ground) discharge. we were losing the RPM signal due to electrical interference on the dyno.

as soon as we tightened the gap to .02 we had signal to 9000 w no problems. we also had no misfires and good power.

the same exact plugs that we used on the dyno from August thru the Texas Mile are currently in my motor. i don't mean the same type of plugs, i mean the the same plugs. they look perfect.

my guess is that if you aren't in the 500+ area power-wise the stock gap, which i think is around .03, would work fine.

BTW, the AR3932 is the largest selling plug within the Autolite Racing plug line...

hc

 

If you're losing spark externally, you have an issue with the boot, wire, and/or lack of dielectric grease, not the plug.

 

wow that is some cheap plugs!

the standard bur9eq here in sweden is like $50 each!! :P
so have bought them on ebay all the time

but now running t04s at 20psi with pumpgas getting 480hp in the engine... should I go with the X version or the regular you think?
you were saying 350-400rwhp could have the X, and higher,550+, should hade the normal style?.. at 20psi I run 435rwhp... so in between?

have the bur9's on leading and ngk sd11a on trailing now without signs of any trouble yet.. but these is cheaper and seems like a good choice for next years track days

 

just noticed this post. You could run such a system, or other microphone-based setup. It still comes down to judgment call of what the signal means. Heavy knock is easy to judge, no knock isn't too hard to judge at lower engine speeds, but "borderline" conditions are very much open to interpretation.

 

I just set up a system like this. I am not listening to it live with headphones as yet, but I record/log with a pc based sound recorder as I do pulls and play it back afterwards. I could then compare it with the ecu data log for analysis. Basically, it just sounds like the engine reving I cant say that I have heard any unusual knocking though. I also used a wrench to tap the engine but I did not hear it on the recording. I use the actual knock sensor signal for the input. Testing is on going.

Does anyone else use setups like this?

 

there is an opportunity for someone to design/build/sell and knock system. they work. BTW, if you hammered the block and didn't hear anything you need to do some additional work.

i believe the CPS/HZ you are looking for is 3500 on the rotary.

i recommend the AR3932 rather than the AR3932X as they offer adj gap.

howard

 

Yes, need I need to filter the signal. That should have read 'I could not hear the sound with the motor running'. With the motor off I can hear the tap of the wrench on the recording.

Will put any additional info in another thread.

 

The stock sensor has an integrated band-pass filter. If you're not creating the correct frequency with your hammer, you won't hear it. Further, proper knock sensing needs to incorporate crank angle windowing. Without this, noise, outside of the narrow window of crank position where knock can actually occur, is interpreted as knock and counter measures are employed. Most systems do not employ this strategy and are therefore of limited value.

 

building a knock system for our cars is probably an opportunity for someone and yes it could be a separate thread.

i do have an active internal knock system in my ECU. current settings: