WS6FirebirdTA00

iTrader: (33)

here is my ve, down low is pretty close to being set, this is with no smoothing done. also higher rpm ranges are done, but here is the dip

HumpinSS

iTrader: (1)

Same dip i had with my 13 with the X4 the dip got deeper

Rick@Synergy

iTrader: (5)

This is common on out VE graphs and you will find this common why you get on a dyno as well. Remeber one thing....your VE table always represents your TQ graph. They go hand in hand. You will find most cams dip in that spot. Your doing just fine.

Rick

bowtieman81

iTrader: (35)

Thanks for the replies fellas. Patrick, good suggestionm. I am running near stock timing; 23-25 degrees down low and 23 at idle. I will try turning that up and see what happens. I was under the assumption I needed to dial in the VE table then work on timing

WS6 and Gman thanks for the pics, but Gman the link doesnt open to any album when I click on it.

I will do some experimenting with these variables and let you guys know how it works out.

Now for

Why do we need so much timing at idle/low rpm with a cam? I would just like a brief tech explanation if anybody knows?

WS6FirebirdTA00

iTrader: (33)

i would think the more timing is needed because iwth the cam it takes more time for the mixture to burn. high overlap cams can keep some exhaust gases in there that dont help speed things up at all.

Patrick G

iTrader: (14)

Because a cam with lots of overlap dilutes the cylinder charge at low rpm and it needs more spark advance to have a more complete combustion process. Think of it as a dirty combustion stroke. Velocity (airspeed) is low which mimicks a poorly designed cylinder head. Just like old school motors with poor cylinder heads, you need to run more advance down low. Basically, the motor is a turd at lower rpm, but some extra timing will help out immensely!

HumpinSS

iTrader: (1)

the extra timing will also add the pep back in the cars step and if it smells it will help clean some of it up

Bink

So that's why my Stank is Less!!

My car is much better since I bumped idle timing advance ( both closed throttle tables) to 31*. You guys were talking about 32* being a big help with Idle - I tried 32* but it surged a little as IAT went up. Maybe it's the Electronic Throttle Control??

Anyway it helped alot and the stink is MUCH less.....I took a 175 mile trip and I didn't stink after the drive.

BTW/FWIW......my cam has 33* overlap @.050". The PCM/EFI does wonders for idle and part throttle response.

bowtieman81

iTrader: (35)

Thats awesome, the wife doesnt like the smell too much (I admit I dont like it either). Thanks again.

Rick@Synergy

iTrader: (5)

The important one is how much overlap at .006? Thats your real overlap.

Rick

bowtieman81

iTrader: (35)

OK, added some idle timing (up to 28 degrees)and some timing in the 2000 rpm and lower cells in main tables (basically took stock table and bumped it up 3-4 degrees in that range).

Results: idle is much smoother now . The rpm doesn't "hunt" nearly as much now. I like.

Low rpm driving shows more response and is smoother now. Definite improvement, but have not eliminated the bucking totally. I think I am on the right track, and will keep tweaking this weekend.

A question: I bumped up timing in the .16 - .36 g/sec area of the main timing table (from 800 rpm - 2000 rpm range).

Should I bump up the timing in the ranges more than .36 g/sec?

WS6FirebirdTA00

iTrader: (33)

go for a ride and log, try to note where the bucking occurs, in what timing cells.

bowtieman81

iTrader: (35)

OK, will do.

But, my question is in general if a cam like ours needs more timing at low rpm, low g/sec to run better does it need more timing in the higher g/sec range (like .36-.52 range)?

I am just trying to determine if, and how much, I should up the timing in the 800-2400 rpm range.

WS6FirebirdTA00

iTrader: (33)

it needs more in the idle range, and from there it needs about 3 deg more or so, just a little more outside of idle range, but not as much as the idle area was increased

Rick@Synergy

iTrader: (5)

Always keep in mind one thing. If you are looking for the perfect ride, put the stock cam back in. So if your cam has slight bucking still and you dont see anymore improvment with other methods, then your good.

You can add timing where you feel you can get away with it. Some things I have others do with their cars when they ask what to do with their table is I ask them to do a compression test. Figure out what your cylinder pressure is, figure out the heat range of the plugs and so forth. This will help the whole combo come together.

Rick

bowtieman81

iTrader: (35)

Thanks WS6 and Rick.

For me I am really after the power this cam can make. My problem currently is 2-fold: I have a decent amount of bucking/stumbling and the powerband is soft in low rpm. If I can get eh power straightened out and reduce the bucking I would be happy. Like I said, I think I am on the path thanks to you guys.

FWIW, my cylinder compression is 200-215 psi in all 8, and I just switched from NGK TR55 to TR6 plugs. The tr55 were showing signs of running to hot. My compression ratio is stock 10:1.

Rick@Synergy

iTrader: (5)

send me your Hpt file to rick@synergymotorsports.net

Rick

WS6FirebirdTA00

iTrader: (33)

Rick knows his ****. I just put some colder plugs in my car, colder than the TR-6. My VE was damn good but I was still getting some knock. The last log I had today, even with heavy engine load, I only saw 2 spots of knock, all under 1*. I run the BR7EF now gapped at 0.045" and my cranking pressure is over 230 psi at 10.2:1 CR. Shoot me your bin if you would like and I can compair ours. Once I get in the power band of the cam its pretty sick. Of course with the stock gearing it doesnt help much with bogging but none the less, still pulls strong.

WS6FirebirdTA00

iTrader: (33)

or just send it to him lol he helped me out with some of my timing issues

Rick@Synergy

iTrader: (5)

Glad you like it now. Should be alot more responsive.

Rick