Joseph Davis

I'm dealing with an 12.5:1 CR D16; A6 block with Y5 head.

With engine correctly timed (ignition) there were noticeable pingies below 1500 rpms with timing at maximum retard of 6 ATDC. I retarded the distributor and fudged the maps a bit and the low rpm pingies went away around 9 ATDC, set timing to 11.5 ATDC in that area until I dyno it next week.

Plugs (ZRF6E-11) look great, piston crowns have formed a healthy carbon coat and exhibit no signs of detonation. Get this - 40.1 mpg off the first half tank, includes the blasting around to seat the rings, a number of WOT pulls to set AFRs, and an average cruise speed of 75-80 mph.


Does anyone have practical experiece with 87 octane? I'm particularly curious about it's knock limit as I am considering a 50 shot.

JDogg

usually when i have a car that has too much compression for the gas we have it takes a big cam to keep it from pinging at low rpms. normally pulling all the timing out makes the car really sluggish and overall unplesant to drive. And instead of a flat timing map that most hondas like i have to pull timing up top. Playing with cam timing can help, although im not sure how much on a single cam. I end up tuning cars for these kids who think its cool to put CTR or the 8cc wiseco pistons in an ls/vtec with a gsr head and stock cams and expect it to run good on pump gas.

i ran 87 in my old gsr motor, it was fine on 87 unless i beat on it for a while.. the 87 ended up killing the exhaust valves, they were pitted and leaking after about 20k miles of 87 and me beating the crap out of it.

Joseph Davis

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">usually when i have a car that has too much compression for the gas we have it takes a big cam to keep it from pinging at low rpms. normally pulling all the timing out makes the car really sluggish and overall unplesant to drive. </TD></TR></TABLE>

In my mind that's primarily due to suction and compression losses from the high CR, single intake valve action, stock short duration cam. Octane not so much... although any time the mix has to be fired off at 9 ATDC my window of best timing is super narrow, exactly as if pushing up against knock limit. Like you say, there probably isn't as much power to be had in that area as if I wanted to pony up the $ for real gas, due to the nature of the setup.

The car has a ZC/Si gearbox, the lower gearing seems to work pretty well and I haven't noticed any loss in power in that region compared to the old EM1-slayer D15B7 drivetrain.

Any $0.02 on a 50 shot? The car's not fast, but it wouldn't take much to hurt the local WRX guys feelings.

JDogg

adding octane will help, but you're right.. the small stock cam is the primary cause

i have only had one setup want the timing atdc.. that was an LS/vtec with 8cc wiseco's a gsr head and stock gsr cams. Once we put the pro2's in the pinging went away and it picked up a TON of power.

as for the 50shot.. i dont do much with nitrous... soo i dont know what to tell you there. i wouldnt try it

Joseph Davis

Wouldn't try it? Bah, you're no fun. You're supposed to encourage me to try these things.


Thanks for the $0.02

JDogg

ok, let me rephrase.... lol

I'D do it.... i would not encourage my customers to do it !


this is why i have a [freak]pwnd h23 from my old prelude... 240k mile h23 with a 150 shot.. made 130 hp na, then 260 on spray, for 2 dyno pulls and about 3 miles.. i never laughed so hard in my life

Joseph Davis

Well, this is my engine, but it is also shiny new and supposed to last a while. I'll spend some time comparing power/timing/etc in the low rpm range where octane is having the biggest effect, and make a judgement call based on that.
I can also start smaller than a 50 shot

Joseph Davis

Got some free time today so I could actually use the dyno for my own car.

I had street tuned the car last week, and simply took large blocks of the ignition map and pulled timing in 4 degree decrements until all audible pinging went away. Survey says: I took out way too much. Today I started out tuning on 87, and adding timing in two degree increments. The baseline run almighty V-Tech was set at 3000, after seeing the huge dip I raised it to 3500, then 4000, then later 3900 to smooth things. Here's baseline, +2, and +4:



Notice everything looks like ragged ***? At 6 degrees advance the graph started to smooth out, here's baseline vs +6:



At this point I was giggling a little. I ended up at ten degrees advance from baseline ignition before I hit near-peak power, and started losing power in some areas. Here's +6 vs +10. Notice where power pinches off at ~3400, I went back and massaged those areas accordingly:



I played around with cam timing a bit but it either caused a significant power loss across the powerband, or dramatically shifted the powerband downward. So, fully massaged 87 octane tune:



At this point it was time to play with octane. I had ~2 gallons in the tank and dumped in 5.6 gallons of 93. I guess the resulting blend was in the ~91 octane range, I could care less about doing the math. Here's back to back 87 vs "93" octane pulls, the only thing changed between the runs was the addition of the 93 octane gasoline:



Joey is soooo not impressed.

I added 2 and 4 degrees timing for some 2 whp and 1.2 wtq gains. The +4 pull made the best power of the day, despite audible pingies throughout the entire powerband. Go figure.



Here's what +6 timing did to the "93" octane tune, notice how the output isn't smooth at all. It did make noticeably more power below 2500, even though it was pinging there too:



I never expected a stock cam D16 to make that sort of power, but to be perfectly honest I think the only other person I've heard of who builds D16 with quench is Mike Belben; he likes to modify PM3 units to suit D16Y chambers. I believe the piston-head combo is where the voodoo comes from; the only time people play around with these engines they run domed (P29) pistons which creates no quench worth noting. If more people start running GX/PDN pistons with D16Y heads I am certain my power figures will be replicated.

0mtber

iTrader: (2)

That is more power then I would expect :-)
Throw a cam at it & see what happens!

Did you ever figure out your sub 1500 rpm pinging solution ?

Joseph Davis

Yes, I did. Timing takes a sharp decline below 1000 rpms when at WOT, at 700 rpms it sits at -11 degrees aka 11 ATDC.

If I bog/stall the engine I end up getting a quick rap or two of spark knock before the engine shuts itself off... I am not sure if I can remedy that, but since it's a stock clutch and easy to drive maybe I can learn to not stall the car out.

JDogg

nice.. looks like its not nearly as octane limited as i imagined.

if you load it up in a high gear does it ping since you put all the timing in it on the dyno?

thats pretty sick, 137hp. i got my hands on an NA single cam last week, it was a y8 motor with a crower cam and p29 pistons with shitty everything else, it made like 125hp or so and pinged its *** off. the timing map had to come down pretty sharply around 1/2 throttle and pretty much leveled out till wot and the same as yours, there was a big decline at low rpms.

Joseph Davis

The only pingies I have had on the road since the dyno is from going parth throttle to WOT or near-WOT in the 2200-2800 rpms range. I smoothed those out on the drive home, this setup is very particular about what timing it wants in the middle of the map, it falls off quite sharply from the timing plateau you cruise in.


Thanks for all the input guys, even if nobody else has done it I like hearing different viewpoints from those in the know.

JDogg

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Joseph Davis &raquo;</TD></TR><TR><TD CLASS="quote"> it falls off quite sharply from the timing plateau you cruise in.
</TD></TR></TABLE>

thats what i was trying to say in my post before.


what kind of dyno do you use?? how do the numbers compare to blueridge's or RLZ's? just out of curiosity.

Joseph Davis

This is Blueridge's dyno. I tuned a stock B16 w/ I/H/E that laid down 142/119 thirty minutes before we strapped my car.

No idea about RLZ's/your old dyno, I've never had a car that was on theirs then BRMS or vice versa. I know what Aaron Lail's MD-1100SE and the WNC Speed Dynojet read for comparison purposes.

mar778c

iTrader: (1)

I know your busy being a "light hearted source of bitterness" but this is very interesting research. Most people won't push the limits of octane like this.

Do you have any plans to do a tear down to inspect the bearings, pistons, and rings?

Oh yeah, thanks for sharing some real tech.

Joseph Davis

I doubt I'll be recreationally tearing the engine down, but if anything ever happens to it I will post pics, and ask some of the local guys some questions. In the mean time you'll have to settle for:

- me peering at the carbon pattern on the tops of the pistons pretty frequently, so far it looks like a healthy fresh motor with good ring seal and tune.

- me checking the bearings by pulling the VTEC solenoid every oil change to look for bearing material, haha.


There's a small chance I'll replace this engine with something else, but that won't be until next summer at the earliest. I need this car to commute relaibly throughout the school year.

GSRswapandslow v2

weak
ricer
hippie
etc...

diaf, pls

JDogg

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Joseph Davis &raquo;</TD></TR><TR><TD CLASS="quote">This is Blueridge's dyno. I tuned a stock B16 w/ I/H/E that laid down 142/119 thirty minutes before we strapped my car.

No idea about RLZ's/your old dyno, I've never had a car that was on theirs then BRMS or vice versa. I know what Aaron Lail's MD-1100SE and the WNC Speed Dynojet read for comparison purposes. </TD></TR></TABLE>

blueridges dyno reads about 10hp higer than the dynojet here. I had alot of guys use their dyno at meets and such.

Aquafina

iTrader: (3)

Torque looks nice.

mike_belben@yahoo.com

if the flame travels fast enough detonation cant happen, so your 87 octane results being pretty much as good as the 93 octane results indicate a pretty lively cylinder.

if you havent already, try grinding back and deshrouding your spark plug ground straps, revealing more of the electrode to let the baby flame kernel get introduced to the fuel a little faster. might have a mild effect on your part throttle pings. if the flame grows faster from its initial spark its like advancing ignition without having to actually pay the efficiency cost of compressing more cylinder pressure nearing TDC.

if you really wanted to get crazy with low octane and high compression, dual plugs would probably be the cats ***. not so feasible, but one can dream.

Joseph Davis

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by GSRswapandslow v2 &raquo;</TD></TR><TR><TD CLASS="quote">weak
ricer
hippie
etc...

diaf, pls</TD></TR></TABLE>

&lt;3 you too, Rob.


<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by JDogg &raquo;</TD></TR><TR><TD CLASS="quote">blueridges dyno reads about 10hp higer than the dynojet here. I had alot of guys use their dyno at meets and such. </TD></TR></TABLE>

You really have to watch where they put the USB weather station widget, it has a direct effect on the STD/SAE corrections. When placed correctly, aka out of direct sunlight or not at a higher level than the car's intake when inside a shop, it reads equal to Aaron Lail's MD-1100SE at the ~200 whp level and is making Dynojet power by 5/600-ish whp.

The Blueridge guys are great with machines, but I guess I lose them with electro-babble. You know how it goes.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mike_belben@yahoo.com &raquo;</TD></TR><TR><TD CLASS="quote">bing!</TD></TR></TABLE>

Gotcha, will try the plug mojo.

ZeroTraction

Sick thread, nice tuning jd. D series are appealing

junkyard racer

so what kind of mpg did you get? same motor, right?

1.5Slowmatic

this build is going to be sick. I know quite a few guys with Stangs that were tuned by aaron Lail on the MD. He does some real good work. BTW what pistons in that A6, the Pm6's?

Uncle Dave

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mike_belben@yahoo.com &raquo;</TD></TR><TR><TD CLASS="quote">if the flame travels fast enough detonation cant happen, so your 87 octane results being pretty much as good as the 93 octane results indicate a pretty lively cylinder.

if you havent already, try grinding back and deshrouding your spark plug ground straps, revealing more of the electrode to let the baby flame kernel get introduced to the fuel a little faster. might have a mild effect on your part throttle pings. if the flame grows faster from its initial spark its like advancing ignition without having to actually pay the efficiency cost of compressing more cylinder pressure nearing TDC.

if you really wanted to get crazy with low octane and high compression, dual plugs would probably be the cats ***. not so feasible, but one can dream. </TD></TR></TABLE>
Mike what if someone was to use a CDI setup instead of the dual spark plug setup ?
Regards Uncle Dave