It's mid upper 90's here most of the time. I came across something on the net about electric pumps and pressure. As the pressure in the system goes up, the electric pumps supposedly start to die down and lose flow unlike mechanical pumps. I'm wondering if that's the case here. I know it pumps well with no pressure but it may not be pumping well under pressure. Makes one wonder. The same radiator kept the engine cool before so I don't think the problem is there. I believe it's in the pump possibly or it's in need of a restriction similar to a thermostat.
1969 Dart Street/Strip (Re)Build
- Thread starter clinteg
- Start date
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It's mid upper 90's here most of the time. I came across something on the net about electric pumps and pressure. As the pressure in the system goes up, the electric pumps supposedly start to die down and lose flow unlike mechanical pumps. I'm wondering if that's the case here. I know it pumps well with no pressure but it may not be pumping well under pressure. Makes one wonder. The same radiator kept the engine cool before so I don't think the problem is there. I believe it's in the pump possibly or it's in need of a restriction similar to a thermostat.
Second TnT day over the weekend didn't go all that well. Made a couple passes on the MT drag radials and just smoked the tires every pass. Tried 21 lbs, then down to 18 lbs. No go and only getting mid to low 11's @ 120-122 mph with 28 degrees total timing. Very hot out, very humid too.
So I got a set of slicks mounted on some Weld draglites a little bit back. The lug tolerance on these wheels are apparently very tight. On the Billet Specialties I've been running, the wheel has a thinner thickness and some of the lugs are tight, but they work. With the Welds which have a deep thickness to them at the lug, the nuts won't start. This is because when the studs were tack welded to the axle, the shop got them crooked. This angularity issue prevented me from even getting the slicks on the car. VERY pissed about that. One solution would be to get another set of axles with 3" studs that are actually straight. That will allow me to use spacers as well and not have any issues with tech. It gets through tech now with the current wheels, but it technically shouldn't with the Welds because the studs are short for those wheels and don't protrude out.
So I lost a lot of time messing with the wheels and then went back to the MT radials. I was trying to find where I was getting my best mph with jetting and note that particular A/F ratio, but the consistency didn't seem to be there. I had it fat, I had it lean, mph varied between 120-122, regardless of what jetting I changed on the carb. Fat was running around 12.9-13.1 (80/84 jetting), two jet sizes down to 78/82 and it was lean (ish) at 13.5-13.7. I wanted to go back 1 jet size to 79/83 but ran out of time. That will probably be the jetting that will be close to optimal, depending on weather conditions. When I start advancing my timing, I may end up starting to fatten it back out too since it was only set at 28 degrees. I know it needs more timing but I was trying to change one thing at a time and it was taking too much time to get many runs. I got 5 passes in with a best of 11.24 @ 122 mph. 60 ft's were terrible. I got into the 1.7's once but was staying mostly in the 1.8's and 1.9's. Had the 60ft's not been so bad, I would have started touching back into the 10's again, but the conditions just weren't there.
So I got a set of slicks mounted on some Weld draglites a little bit back. The lug tolerance on these wheels are apparently very tight. On the Billet Specialties I've been running, the wheel has a thinner thickness and some of the lugs are tight, but they work. With the Welds which have a deep thickness to them at the lug, the nuts won't start. This is because when the studs were tack welded to the axle, the shop got them crooked. This angularity issue prevented me from even getting the slicks on the car. VERY pissed about that. One solution would be to get another set of axles with 3" studs that are actually straight. That will allow me to use spacers as well and not have any issues with tech. It gets through tech now with the current wheels, but it technically shouldn't with the Welds because the studs are short for those wheels and don't protrude out.
So I lost a lot of time messing with the wheels and then went back to the MT radials. I was trying to find where I was getting my best mph with jetting and note that particular A/F ratio, but the consistency didn't seem to be there. I had it fat, I had it lean, mph varied between 120-122, regardless of what jetting I changed on the carb. Fat was running around 12.9-13.1 (80/84 jetting), two jet sizes down to 78/82 and it was lean (ish) at 13.5-13.7. I wanted to go back 1 jet size to 79/83 but ran out of time. That will probably be the jetting that will be close to optimal, depending on weather conditions. When I start advancing my timing, I may end up starting to fatten it back out too since it was only set at 28 degrees. I know it needs more timing but I was trying to change one thing at a time and it was taking too much time to get many runs. I got 5 passes in with a best of 11.24 @ 122 mph. 60 ft's were terrible. I got into the 1.7's once but was staying mostly in the 1.8's and 1.9's. Had the 60ft's not been so bad, I would have started touching back into the 10's again, but the conditions just weren't there.
younggun2.0
Well-Known Member
I have heard that its best to find optimal timing for your combo FIRST. as it effects air/fuel mixtures. I know that advancing my initial timing leaned my car way out at idle. what was your air/fuel # at the top end of the track? I have my wideband set up and will be making passes friday. my car idles right now at 12.9-13.1 and at WOT up round 5000rpm im 13.9-14.1
You're probably right about the timing. I'll probably try that first next time. It's much easier to change that than jets. It sounds like your WOT is very lean. From what I've read, you want to be closer to 13.0-13.5 ish depending on the motor at WOT. That's where I was aiming. I was 12.9-13.1 at WOT and when I dropped a couple jet sizes it went to 13.5-13.7 so it was went to the lean side. Didn't get any changes in after that. At the moment I have idle at 14.7, cruise at 2K rpm it's around 13.7. I've been changing air bleeds like crazy trying to get it leaned out to at least 14.0 at crust and idle whilst getting mid low 13's at WOT. Before, it was 11's anything off idle which is why I get 5 mph. Going to change that.
Mad Dart
Nothing to see Here!
You are fat at idle big time and very lean at WOT. Be careful with that.
younggun2.0
Well-Known Member
Would jetting up 2 sizes on secondaries be a quick fix? You think 14.0 is way lean on top end? Sounds like need to up secondary and go down on primary.
Sorry for hijack but I am only 3/4 turn out on all 4 air bleeds Would the primary jet cause rich idle?
Mad Dart
Nothing to see Here!
1) this is your 383 right?
2) What carb ?
3) Initial timing ?
4) Total timing?
More advance on initial timing could fix the idle readings. Some would prob start with disconnecting the secondary's " butterfly & acc pump " then dial in the primary's first on jetting. Then re connect the secondary's & do the same thing until you get your A/F in the 12.8 range at WOT.
Remember timing first then start messing with the carb. Idle circuit, primary, then secondary.
I just bought EFI for the Scamp that is supposed to self tune. Converting to e85. I am hoping it works well and I can get away from the carb tuning stuff for good. A procharger will be up to bat after its installed & dialed in. I will be posting play by play as usual on my Scamp thread.
Oh yeah, 14.0 is way lean up top. I would fix that before you run at the track. Primary jet won't have anything to do with idle. It will only affect cruise and WOT. Are you running a Holley? If so, there's a lot of info out there on how to get them right. I can send you info if you want. Moving the idle circuit air bleeds from the top of the metering block to the bottom and get those bleed sizes down would be a place to start for idle. You should be around 1.5 turns out on your idle screws. On mine, I've done that and blocked one emulsion hole in the metering block and changed the air bleeds in the main body. Will probably end up blocking 2 of the emulsion holes since I'm still on the fat side at cruise, but it's a lot better. The aim is to keep the front main jets as small as possible so you're not fat as heck at cruise and then getting the right power valve for WOT operation aiming at 13.0-13.5. For tuning purposes, I've blocked the PVCR's and plugged the PV as well so it's nothing but low end operation. Without a power valve and having small jetting in the front mains, it will lean out like crazy so no WOT when doing this. Once that is worked out, then the PV is the last thing to get that WOT correct. THEN you'll move to the secondaries if needed. I haven't got that far yet. So far every little tweak is helping idle and cruise quality. I was always double footing it at stop lights and now I'm not even having to touch the gas hardly at all to keep it idling.
Got my dad, aunt, and uncle in the car over last weekend. My uncle had funny some facial expressions while my dad and aunt laughed about the whole time! They had a lot of fun. Check out the ride
[ame]http://youtu.be/7xGMALoMf5c[/ame]
[ame]http://youtu.be/7xGMALoMf5c[/ame]
rayer:way kewl
mopowers
Well-Known Member
What a cool video! Thanks for sharing. Your dad cracks me up. I love how your aunt wouldn't stop giggling. Such a cool video, man. That's what this ****'s all about.
Priceless =D>
Love theese rides
Love theese rides
bkd
No more Scoops
Love it, That was out standing Fantastic! Thanks for sharing
SpeedracerX
Still on this side of the dirt member
Dude that video was awesome!!! Your uncles faces were cracking me up... You need to mount a go-pro on the outside of the car as well (like on the quarter panel) to get some exterior shots to edit in lol.. Your videos are outstanding... and the Dart... Just plain badass!!
Alex5280
74' Duster
Loved the video! So darn cool!
66340SEDAN
FABO Member #3649
x2!
Your uncle is funny in that video.
junior636
Well-Known Member
I had to watch the video a few times, your uncle cracks me up. Can't wait till i can scare the crap out of some family lol.
My uncle thought the camera was facing forward so he didn't know it was video taping us. I would like to get another GoPro that I could put somewhere else for another view like outside the car looking back, forward, whatever. I haven't convinced the wife that I need the second GoPro yet. I see the "need", she doesn't lol.
Your Uncle is a character! Lol. Great video.
SpeedracerX
Still on this side of the dirt member
let her read these comments... the need is real my friend LOL ... I am already looking forward to your next video
Another little vid I put together. A friend Bill and I went for a cruise. He's a member here but not on much. This was our first time out cruising together. Traffic was heavy so not a lot of craziness.
Oh and his is a 440 car.
[ame]https://youtu.be/EGO3oLYfCKs[/ame]
Oh and his is a 440 car.
[ame]https://youtu.be/EGO3oLYfCKs[/ame]
SpeedracerX
Still on this side of the dirt member
nice!!
That RUNS HARD... absolutely love it!
I tell you what, it's tough not to drive this car every time I take it out. It loves rpm!
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