Lars...Will this really increase mpg
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
1st
if lars wanted to, he would have tried the 4 holer weeks ago(maybe years ago, or decades ago). HE IS NOT INTERESTED! GOT IT!
.
First map out the pinging.
What rpm? WOT?
accel from cruise? all rpm's or just some.
Then plot the advance curve w/timing light, no vac advance.
.
Myself, I'd want to do a quick mpg check, so i'd just turn the dist CW and see if it stops pinging and runs fair enough for a mpg test. Precise tuning will add 1-2 mpg, but why bother today, when all the fun is the mpg?
if lars wanted to, he would have tried the 4 holer weeks ago(maybe years ago, or decades ago). HE IS NOT INTERESTED! GOT IT!
.
First map out the pinging.
What rpm? WOT?
accel from cruise? all rpm's or just some.
Then plot the advance curve w/timing light, no vac advance.
.
Myself, I'd want to do a quick mpg check, so i'd just turn the dist CW and see if it stops pinging and runs fair enough for a mpg test. Precise tuning will add 1-2 mpg, but why bother today, when all the fun is the mpg?
Well to be honest I'm not here to bash anyone. I'm trying Matts idea so that shows I am willing to try, but I also need timing help and I know Lars is apprently the go-to guy for timing.
I really don't care who makes the suggestion on what I should run, I just want the suggestion
I really don't care who makes the suggestion on what I should run, I just want the suggestion
You could try leaving your initial where it is and disconnecting and plugging off the vac adv. to the dist-that should stop the pinging.Take a milage check with it disconnected and then reconnect and back timing down and recheck milage again.
In the end I would think you are going to want to tune for power and then find a vac can that will work without pinging unless your primary concern is fuel milage.I realize we are talking milage but not sure how much perf. your willing to give up.
Last edited by ...Roger...; Nov 28, 2007 at 12:39 PM.
Racer
Joined: Mar 2004
Posts: 292
Likes: 2
From: Plumas Lake CA
defsegx, your motor is probably going to need a little less than 36 deg total (excluding vacuum advance) with those efficient TF heads and 11 to 1 compression. Efficient heads like that probably only need 32 deg or so. You are a prime candidate for a dyno tune now. You need to determine wether it's pinging from being lean, or from too much total timing.
IMHO, you could double check how much vacuum advance your're getting now. If your total (vac plus initial plus mechanical) is much over 52, I'd adjust the vacuum adv down - especially if it's pinging under light load. Then, I'd start backing down your initial a couple of degrees at a time to determine the best static setting. I'm guessing around 32 deg (intial plus mechanical). Basically, timing it per Lars' papers but with a lower "ideal" timing setting to compensate for your more efficient heads/stroker.
IMHO, you could double check how much vacuum advance your're getting now. If your total (vac plus initial plus mechanical) is much over 52, I'd adjust the vacuum adv down - especially if it's pinging under light load. Then, I'd start backing down your initial a couple of degrees at a time to determine the best static setting. I'm guessing around 32 deg (intial plus mechanical). Basically, timing it per Lars' papers but with a lower "ideal" timing setting to compensate for your more efficient heads/stroker.
Race Director
Joined: May 2006
Posts: 16,528
Likes: 53
From: Dayton, Ohio
looking at pic #2, once u put a 4 hole plate on it, there appears to be only 1 place of ~1/4" at each butterfly for air to sneak across. Just enough for vacuum acc. like PB etc. That is excellent, must seal up 70-90%.
I would NOT epoxy the last little bit, not at this time, on a qjet.
I would NOT epoxy the last little bit, not at this time, on a qjet.
Race Director
Joined: Oct 2000
Posts: 15,013
Likes: 79
From: central FL, near the beach.
1st
I'm not bashing lars; he is a great guy! But, if lars wanted to, he would have tried the 4 holer weeks ago(maybe years ago, or decades ago). HE IS NOT INTERESTED! GOT IT? His tuning is VERY successful as long as u don't demand top mpg.
.
First map out the pinging.
What rpm? WOT?
accel from cruise? all rpm's or just some.
Then plot the advance curve w/timing light, no vac advance.
i'll take a guess at 17 base 32 total.
i'd set the base at 20, and set the weights for another 15, that's 35, and i figure it will ping, but u won't know until u try. turn the dis CW-clockwise, until it stops pinging, or rarely pings slighty.
DISCONNECT the vac advance for ping testing.
CLUE: sometimes it is causing the ping and the can has to be changed.
Myself, I'd want to do a quick mpg check, so i'd just turn the dist CW and see if it stops pinging and runs fair enough for a mpg test. Precise tuning may add ~1-2 mpg, and better drivability, but why bother today, when all the fun is the mpg?
I'm not bashing lars; he is a great guy! But, if lars wanted to, he would have tried the 4 holer weeks ago(maybe years ago, or decades ago). HE IS NOT INTERESTED! GOT IT? His tuning is VERY successful as long as u don't demand top mpg.
.
First map out the pinging.
What rpm? WOT?
accel from cruise? all rpm's or just some.
Then plot the advance curve w/timing light, no vac advance.
i'll take a guess at 17 base 32 total.
i'd set the base at 20, and set the weights for another 15, that's 35, and i figure it will ping, but u won't know until u try. turn the dis CW-clockwise, until it stops pinging, or rarely pings slighty.
DISCONNECT the vac advance for ping testing.
CLUE: sometimes it is causing the ping and the can has to be changed.
Myself, I'd want to do a quick mpg check, so i'd just turn the dist CW and see if it stops pinging and runs fair enough for a mpg test. Precise tuning may add ~1-2 mpg, and better drivability, but why bother today, when all the fun is the mpg?
i type slow and it can take time to finish
Pro
Joined: Oct 2007
Posts: 587
Likes: 0
From: Overland Park Kansas
Hollly crap. Ok I just went and played with the timing a bit. I had to drop the final down to 27 to stop it from any noticable ping. That dropped my initial down to 7. I forgot to test drive it with the vac disconnected though, i reconnected it before I went driving.
I'm really a newb to timing, is it horrible to have the idle timing at 7?
I'm really a newb to timing, is it horrible to have the idle timing at 7?
Race Director
Joined: Oct 2000
Posts: 15,013
Likes: 79
From: central FL, near the beach.
i'm confused,
27 no vac advance, then u connected it? has to be disconected at first.
tuning can be a long process for a newb
i'd expect it to stall at idle at 7; is that why u connected it?
fill out your profile. i just looked to see what rear and trans u have. stall speed?
don't expect me to remember it, i need it where i can find it.
27 no vac advance, then u connected it? has to be disconected at first.
tuning can be a long process for a newb
i'd expect it to stall at idle at 7; is that why u connected it?
fill out your profile. i just looked to see what rear and trans u have. stall speed?
don't expect me to remember it, i need it where i can find it.
Last edited by Matt Gruber; Nov 28, 2007 at 07:32 PM.
Pro
Joined: Oct 2007
Posts: 587
Likes: 0
From: Overland Park Kansas
Maybe I can explain better. I set it to 16 base, 36 all in and then connected the vac and drove it. It was pinging, so I retarded it until it stopped. When I got back and checked it, it was set at 7 initial and 27 all in.
Rear is 3.55, trans is auto w/2800 stall.
Rear is 3.55, trans is auto w/2800 stall.
Last edited by neuroclast; Nov 28, 2007 at 07:50 PM.
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Pro
Joined: Oct 2007
Posts: 587
Likes: 0
From: Overland Park Kansas
Well I haven't done anything else since last night, but I can tell you it feels a lot slower from the seat of the pants. I don't know if it's because I had to retard the timing so much or what, but it feels weird to me.
Still waiting to see on MPG, but right now I'm sitting at 110 miles on half a tank and I've got on it pretty hard a few times.
Still waiting to see on MPG, but right now I'm sitting at 110 miles on half a tank and I've got on it pretty hard a few times.
Burning Brakes
Joined: Sep 2005
Posts: 832
Likes: 0
From: Sarasota Florida
Matt, i'm sorry this is totally off track from where this thread is heading now...but i never understood what to do as far as filling in the gaps on the carb because it blocked the pcv and brake booster. then i divided it so the pcv get vacuum on one side and the brake booster on the other. there was some kind of pressure building up in the pcv because it would slowly push it's way out of the valve cover.
Race Director
Joined: Oct 2000
Posts: 15,013
Likes: 79
From: central FL, near the beach.
Matt, i'm sorry this is totally off track from where this thread is heading now...but i never understood what to do as far as filling in the gaps on the carb because it blocked the pcv and brake booster. then i divided it so the pcv get vacuum on one side and the brake booster on the other. there was some kind of pressure building up in the pcv because it would slowly push it's way out of the valve cover.
Pro
Joined: Oct 2007
Posts: 587
Likes: 0
From: Overland Park Kansas
No vacuum on the interior, i have one but it's a mityvac. And it idles at about 700.
new problem now though, think either my diffy is screwed or a ujoint is toast, back wheel locking up and bad noises
new problem now though, think either my diffy is screwed or a ujoint is toast, back wheel locking up and bad noises
Burning Brakes
Joined: Sep 2005
Posts: 832
Likes: 0
From: Sarasota Florida
Race Director
Joined: Oct 2000
Posts: 15,013
Likes: 79
From: central FL, near the beach.
.
I don't use a pcv valve. i hook the breather to the center of the air cleaner bottom. works better than any pcv valve. i use mopar breathers that take a 5/8" hose. Thanks for trying the mod
Burning Brakes
Joined: Sep 2005
Posts: 832
Likes: 0
From: Sarasota Florida
without a pic i'd just be guessing. Did u check the vacuum before hooking it up?
.
I don't use a pcv valve. i hook the breather to the center of the air cleaner bottom. works better than any pcv valve. i use mopar breathers that take a 5/8" hose. Thanks for trying the mod
.
I don't use a pcv valve. i hook the breather to the center of the air cleaner bottom. works better than any pcv valve. i use mopar breathers that take a 5/8" hose. Thanks for trying the mod
Race Director
Joined: Oct 2000
Posts: 15,013
Likes: 79
From: central FL, near the beach.
ANDY
yes! hook it to the manifold; unlimited flow there. Only catch is, usually there is only 1 port; so u'd have to drill & tap the other plane; too much work, so i'd try PB from manifold, pcv from the carb; try switching the 2.
i'd guess the epoxy is blocking the flow some.
yes! hook it to the manifold; unlimited flow there. Only catch is, usually there is only 1 port; so u'd have to drill & tap the other plane; too much work, so i'd try PB from manifold, pcv from the carb; try switching the 2.
i'd guess the epoxy is blocking the flow some.
Burning Brakes
Joined: Sep 2005
Posts: 832
Likes: 0
From: Sarasota Florida
ANDY
yes! hook it to the manifold; unlimited flow there. Only catch is, usually there is only 1 port; so u'd have to drill & tap the other plane; too much work, so i'd try PB from manifold, pcv from the carb; try switching the 2.
i'd guess the epoxy is blocking the flow some.
yes! hook it to the manifold; unlimited flow there. Only catch is, usually there is only 1 port; so u'd have to drill & tap the other plane; too much work, so i'd try PB from manifold, pcv from the carb; try switching the 2.
i'd guess the epoxy is blocking the flow some.
Race Director
Joined: Oct 2000
Posts: 15,013
Likes: 79
From: central FL, near the beach.
i didn't use epoxy. i used a cork like material that fit very snug. i though about running the PB from the manifold. i could just put a T by the one port. i'm just not too sure about the PCV idea. anything's worth a try though, i guess. i'm definitely not going to drill my manifold lol.
Have u tried the 4 holer by itself, no cork?
Burning Brakes
Joined: Sep 2005
Posts: 832
Likes: 0
From: Sarasota Florida
there vacuum wasn't strong enough for the PCV. I think the brakes still worked fine though.
So if I were to run the PB off manifold vacuum and close the other port on the carb, will it take vacuum away from the other things on the vavuum port?