[johnwohl]

tl;dr What is the right base ignition timing for a d16a6/y8 setup, and how much percentage fuel to I need to add to the p28 base map to avoid bad things happening with the 11:1 compression?

long version:

I've working with a d16a6/y8 mini me combination with an adjustable cam gear and I'm having a rough time figuring out exactly what is the correct cam position (no advance/retard).

I am starting out with the index marks on the cam gear lined up with the deck. The height is different on the two heads or something so the belt is off by half a tooth. I fixed this by just moving the cam ring over half a tooth, not actually moving the cam.

If I'm not mistaken, that should the cam where it needs to be and I shouldn't need to adjust the cam itself anymore should I?

Here is where my problem comes in. With the cam at that position my ignition timing is massively retarded. I would guess it's at maybe 8 or 12 degrees and no amount of advance on the distributor will get it much closer to the 16 degrees mark.

I also understand that since the y8 obd2 setup runs a knock sensor, it's base ignition timing is 12 instead of 16. I get all screwed up right about here. Do I need to move the cam to get the base ignition timing closer to the 16 degrees, or do I leave the cam alone and add 4 degrees to my timing maps in crome? Or is 12 degrees base timing just fine considering the 11:1 compression?

Also, as a side note, I'm wondering how much additional fuel I need to add as a base tune to avoid hurting anything. I was thinking maybe 5 or 10 percent added to the standard p28 base?

 

[transzex]

What cam gear do you have?

 

[hatchaddict]

what is the adjustable cam gear for cause the y8 cam gear index key is a hlf tooth different then an a6 or z6 http://www.d-series.org/forums/engine-building/41363-y8-cam-w-z6-sprocket-z6-cam-w-y8-sprocket.html

 

[johnwohl]

It's a generic ebay d series cam gear, so yeah, it's probably not indexed for the d16y8.

so do I need to advance or retard it 4 degrees after lining it up with the deck?

thanks for the help btw, i appreciate it. this has been giving me fits.

 

[johnwohl]

Warning: I have no mspaint skillz.

If I'm getting this right, I need to advance the d15/16 cam gear by 4.5 degrees to account for the offset key on the y8 cam.

Just to make sure I got this, i drew a diagram. The left drawing shows an adjustable cam gear made specifically for the y8, with the offset key. The right drawing shows what I think I need to do to get the timing right with the d15/15 adjustable cam gear with no key offset.

Am I on the right track here?

 

[Lukefsi]

Do you have the stock y8 cam gear? You can use that for refrence when lining up your cam.

 

[johnwohl]

I did think of that, and unfortunately I can't find the stock cam gear to save my life QQ

 

[Lukefsi]

Do you still got the A6 cam gear? If your adjustable one has different tdc marks then your a6 gear then its most likely the y8 one, if they're the same then is a a6 one.

 

[johnwohl]

its definately not a y8 cam gear. the 12 o clock mark is right on the tooth, rather than between teeth like on the y8 cam gear.

 

[91dohccivic]

I had the d15b2 bottom end with a z6 top end with the y8 cam gear. I ened up having to set the y8 cam gear on tooth back to get my timing right. just try advancing your gear one tooth if that dosnt work good then go back one tooth make sure you turn your engine over by hand before you try to start tho. dont want to bend any valves.

 

[johnwohl]

Well... I tried retarding it 4 degrees and it lost power but felt pretty smooth. I tried advancing it four degrees and it seems like it gained a little top end but bogs down REALLY bad at low rpm. So it seems like maybe I'll just leave it where I had it until I can get it on a dyno.

Maybe it was right when I had it retarded 4 degrees but I needed to add ignition timing or something?

Any ideas?

 

[Lukefsi]

Are you redoing the ignition timing when you move the cam gear?

 

[johnwohl]

So for anyone who wants to know, here's what I ended up doing.

I found out that the y8 cam gear has a key offset of 4 degrees retard on the cam (8 degrees crank), so I set the z6 adjustable cam gear with the timing marks lined up with the deck, crank at tdc, and then retarded the cam 4 degrees. Now the cam and the crank are where they should be in proper mechanical relation to each other. It's hard to verify this with a timing light because the ignition timing is so screwed in the first place.

Due to several factors including deck height, the cam offset, the belt that you have to use for the mini-me, etc. the ignition timing is just fucked up at this point. If you try to run it with a stock p28 or p30 rom, the ignition timing will at like 8 degrees advance, and the car will run like ass, if at all.

What I did was got ahold of a rom that somebody made that has the p2p fuel and timing maps on a p30 rom, and started with that. Those timing maps may work with a stock d16y8, but for my purposes they were garbage, not to mention that they are a minimum map which on the p2p are adjusted by the knock sensor and other things which my car does not have. The fuel maps work well though.

I got out the timing light and the ostrich, and just started adding 4 degrees advance to both high and low ignition maps in crome until I got my ignition timing at 16 degrees BTDC. The timing map expects the mechanical timing to start out at 16 degees advance but with this setup, once the mechanical timing is right, you will start out no where near that, so you will end up with a pretty scary map, with like 28 degrees advance at idle, but since it's all relativeto where I started in the first place, who cares.

This was quite a large pain in the ass to figure out. I wish I would've just gotten a z6 head like everyone else but nooooo. I had to have the higher compression with the oddball y8 head. But now at least I have it running off a good basemap until I can get some dyno time. It rips around pretty well on just this basemap, so I'm very excited to see what kind of numbers I can put down with everything optimally adjusted.

Once I have everything nailed down, I'll post a setup specific basemap and a tuned map in a couple of places in case anyone else is dumb enough to try this crap. Geez, talk about a headache.

So, in conclusion:

d16a6 d16y8 mini me, DONT DO IT BRO. go the easy route and stick with the z6.

 

[DocHudson]

I'm hoping these will somehow closely resemble what you have done so far...

I came up with these two maps from a past and a current setup.
The P2P was used with a A6/Y8 setup with a crower2 cam.
The ZC map is currently used with the same cam, head and block except for P29 pistons.

Most of the attention was on lowcam cruising driveability and not so much on hicam wot performance as you will notice low timing maps there.

The timing maps do look scary but IMO it's really how a Y8 map should look like on a P30.

In case you try these, may I ask if you can PM me your feedback or post em here. Whichever.

28 degrees idle timing you say? hmmm..
I'm gonna give that a try someday...i figure it'll bring the dizzy towards the middle more with a MUCH scary-er looking timing map across the board. LOL
Mine's pushed almost all the way to the firewall side with only ~21.75* to ~22.75* respectively on each map.

 

[fireant]

This turned into a very informative thread... I hope to hear more from the results.