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DP Intake, my observations...

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Ronbo
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DP Intake, my observations...

Post #1 by Ronbo » Fri Nov 18, 2005 5:15 am

I've had the thing on my truck roughly three years now with a holley 390, both were brand new out of the box. I'm running hooker headers also.
1. No matter how well you tune the holley you cannot get an even mixture across all cylinders. With number one burning good, numbers 5 and 6 run lean and 3/4 are rich.
2. I've always had a stumble, its not always there but wait a minute and its going to come back. I believe this is due to carb orientation.
3. It has great bottom end and I cant comment on the top end because I think my stock cam runs out long before the intake/carb hits its full potential.
4. You need to have a hot water spacer if the temp drops into the 30s or if you have high humidity conditions and low temps (ie Georgia).
5. It is a bear to keep the headers and intake sealed. On the forum there is a solution using chevy studs and washers. I haven't tried that myself but others commented it works well.
6. As far as fuel economy goes....Whatever I do to it I get 10-12 mPG, flogging it, babying it, carrying a load, towing, changing timing and power valves it just doesn't seem to matter. So I just keep the hammer down and enjoy the fact that my six is catapulting a 3000lb brick through the air! 8)
Just my observations.

Ron
2017 F-150 Lariat ECO Boost
2011 F-150 Lariat ECO Boost
68 Mustang, power drums/steering, AC, single outlet coated header, Holley 350, DS II w/Accel super coil
80 Goldwing (half the Mustang :))

Seattle Smitty

Post #2 by Seattle Smitty » Fri Nov 18, 2005 3:02 pm

Does your manifold have the hot water spacer or any kind of hot spot under the plenum?

Ronbo
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Post #3 by Ronbo » Sat Nov 19, 2005 6:32 am

It has a finned radiator sort of thing. I guess it is supposed to collect heat from the exhaust manifold/headers but the water heated spacer is a better choice, I didn't need it when I was in AZ but here in GA you need it!
2017 F-150 Lariat ECO Boost
2011 F-150 Lariat ECO Boost
68 Mustang, power drums/steering, AC, single outlet coated header, Holley 350, DS II w/Accel super coil
80 Goldwing (half the Mustang :))

Seattle Smitty

Post #4 by Seattle Smitty » Mon Nov 21, 2005 2:13 pm

It is supposedly a general rule that a "hot spot" under the carb will tend to even out the cylinder-to-cylinder fuel distribution. This rule would predict that you'd have seen somewhat better fuel distribution in Arizona summers than you do in Georgia winters. Did you see this actually occur?

As far as the fins on the bottom of the manifold picking up heat from above the exhaust manifold, how effective do you find that to be? On my '66 Econoline 240, the iron intake manifold got VERY hot. But it was bolted directly to the exhaust manifold (with a laminated gasket between them). There was a temperature controlled bafffle in the exhaust which directed heat to the underside of the intake during cold starts. In my van, I disabled this feature by wiring the baffle shut, but enough exhaust gases leaked around the edges of the baffle to keep the intake amazingly hot at all times. I planned to fabricate exhaust and intake manifolds that were better separated, but never did, and sold the van.

mepr

Post #5 by mepr » Tue Nov 22, 2005 2:30 am

i was way more than pleased whith my Clifford stuff on my 82. My only gripe whith em is that it took a month and a half to get the parts. But i have never had problems whith them leaking or whith cold startups. And the clifford stuff has a water passage through the bottom of the intake aswell.

Ronbo
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Post #6 by Ronbo » Tue Nov 22, 2005 4:54 am

S.S.- In Az/Tx I never noticed a problem with it. When I got here and my mileage went to heck and I started having trouble keeping it running I starte4d digging. Makes sense though, when the temps started dropping the problem occurred. The intake isn't nearly as hot as summer.

mepr- I like the idea of a water passage. I'll just have to scout around for a spacer with one.
2017 F-150 Lariat ECO Boost
2011 F-150 Lariat ECO Boost
68 Mustang, power drums/steering, AC, single outlet coated header, Holley 350, DS II w/Accel super coil
80 Goldwing (half the Mustang :))

MustangSix
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Post #7 by MustangSix » Tue Nov 22, 2005 2:32 pm

Ford carb spacers from several sixties models were water heated, like thi s one.
Jack Collins

Seattle Smitty

Post #8 by Seattle Smitty » Tue Nov 22, 2005 3:31 pm

A "hot spot" under the floor of the manifold should be much more effective than a water-heated spacer. If you're willing to remove your manifold, you could weld a short length of aluminum square tube to the bottom of the mainfold; cap the ends of the square tube, and drill and tap for hose fittings. When welding, bolt the intake to a spare head (borrowed from your machine shop. Grind the areas to be welded down to shiny metal. Preheat the parts to around 175-200F.

If you don't weld, you could still try doing the job yourself, using the aluminum "torch-brazing" rod they sell at hot rod shows (welding supply stores can get it). Make a generous deposit of this material, and pressure-test when it cools. I don't THINK you will get enuf heat radiating out from the exhaust manifold to melt your joints . . . but welding would be safer.

You might want to use this manifold heater all winter, but disconnect it for the summer for slightly better fuel economy (maybe). Or install a heater control valve in the line.

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DaGr8Tim
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Post #9 by DaGr8Tim » Tue Nov 22, 2005 3:39 pm

In addition to Smitty's post. I've seen cars (like my topaz) that had a tapped hole in the exhaust manifold. To that was bolted a flat plate with a nipple about an 1 1/2. Then a hose ran from the nipple to the air box. The air box had a flap that worked similar to a thermastat and the contracting metal (when it was cold) opened the flap. Once everything warmed up, the flap closed.

With the flap open, it blocked off all or most of the air from the outside. Although this setup may be difficult to do in a carrbed car with a round air cleaner.
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sundog
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Post #10 by sundog » Tue Nov 22, 2005 8:19 pm

The offy dp manifold has a provision on the bottom for bolting it to the stock exhaust manifold, which would be a good source for "hot spot" heating. I have efi duals, which have no provision for bolting to the intake. I made a plate with heater hose fittings to bolt to the intake in place of the exhaust manifold (you can find this in the tech section of the Inliners International website). Hot water will be slower to heat the manifold, but it will work all the same. I do not have the offy on my 300 yet, but will before the year is out. With lean primaries in the 4bbl and water heat to the manifold, I'm hoping for a mileage improvement if I can resist the anticipated extra available power.
'77 F250 stock 400m c6 dana60/3.54, it was dad's
'81 F250 4wd, 300, efi duals w/2.25 pipes, offy 360dp, holley 390, t18, 3.54s
'70 F350 stock 360, np435, d70 w/4.10s, grain truck w/hoist

Seattle Smitty

Post #11 by Seattle Smitty » Fri Nov 25, 2005 2:42 pm

I don't care for the old Ford six system of bolting the intake directly to the exhaust hot-box. Yes, it gives the quickest warmup, which is a very good thing. But after the bi-metal spring gets hot and closes the baffle, there is still enough exhaust leakage around the baffle (added to the heat radiated from the exhaust manifold) to keep the entire intake manifold quite excessively hot. I haven't seen Tim's hot-box-with-tube system; maybe that works better.
But most headers don't have the hot-box anyway, and good street headers are recommended by all of the experts here as a way to wake up the Ford sixes for both power and economy. So I prefer a localized hot-spot under the plenum using hot water, which you can shut off as desired.
To get a temporary cold-start source of heat, fabricate a sheetmetal cuff over the headers, and connect it to the aircleaner snorkel with flex-tubing per normal Detroit practice, with a hot-cutoff door in the snorkel. That cuff will have the added advantage of shielding the intake from radiated exhaust heat to some extent.

It's quite a balancing act, isn't it?! You need a lot of heat, for a short time, then a little heat, quite localized, but only during cool weather, and you have to choose among various heat sources, some of which are very controllable and others less so. But this is a FUN kind of car project, where you get to be creative, and demonstrate your shop skills, plus there's a dollars-and cents payoff thereafter. Win-win!!

cjbronco

Post #12 by cjbronco » Mon Nov 28, 2005 9:18 pm

Yeah im having the same problem. I live in NJ and its humid and hot in the summer and cold n dry in the winters. I have horrible warm up times. Takes a good 5-10 min and that right at freezing. My mileage is always 11-12 any way I drive. Im looking at maybe jsut running my hot water heater hoses through/around the intake to help slightly with warm up. Wrapping the ehaders w/aluminum. I may also go back to a stock airt filter setup with the flew metal heater hose that goes to the exhaust manifold and just incorporate it into my header some way. I've also heard of these in line block heaters. From what I understand it does in the lower rad hose...? Dont know more than that really. But I need some help quick w/winter coming soon.

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red(neck+truck)
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Post #13 by red(neck+truck) » Mon Nov 28, 2005 9:31 pm

highly recommend the lower radiator hose heater. im going into the tird winter with mine and have not had to ues the manual choke since i put it on
1976 f250 extended cab camper special 300 I6 stock intake 2v spacer autolite carb and efi exhaust. best
running combo yet
2007 kawisaki 500cc vulcan
2002 honda crv (the wifes car)

cjbronco

Post #14 by cjbronco » Tue Nov 29, 2005 7:36 am

does anyone know how this works or can someone explain to me exactly what it is or how it works?

Lazy JW
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Post #15 by Lazy JW » Tue Nov 29, 2005 8:46 am

It is just a small electric heater (120 volt ac) that fits in the lower radiator hose. Typically you have to cut the hose, insert the heating element, and put hose clamps on to hold it all in place. A 500 watt unit will do wonders for your warm-up time.
Joe
"The White OX" 1974 F-350 300-6, Stock single exhaust, Carter YF, T-18A, Dana70 w/4.11, Flatbed dually w/dump bed. "Where no oxen are, the crib is clean, but much increase is by the strength of the ox" (Proverbs 14:4)
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Post #16 by metalz » Tue Nov 29, 2005 9:28 pm

Hello

I live in Alberta where it gets to be -40, I prefer dual block heaters inserted in the core plugs (or frost plugs as they are sometimes called). I installed them one plug back from the front and one plug ahead from the rear. Takes 2 hours at -40 to have warm coolant.....oil is another thing. I shy away from the radiator hose heater due to the restriction imposed by the heating element in the way of coolant flow. This is not an issue in the winter, but in the mountains in summer (90+ degrees) it could be an issue.

Regards

MetalZ

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red(neck+truck)
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Post #17 by red(neck+truck) » Tue Nov 29, 2005 9:35 pm

the element has the same amount of flow as the normal hose. ive run my truck up hill at about 10 mph on a 100+* day and never had it even attempt to over heat
1976 f250 extended cab camper special 300 I6 stock intake 2v spacer autolite carb and efi exhaust. best
running combo yet
2007 kawisaki 500cc vulcan
2002 honda crv (the wifes car)

cjbronco

Post #18 by cjbronco » Tue Nov 29, 2005 10:00 pm

so what do ya think about a 60's t-bird water heated carb spacer for a 4bbl? Thats about the only other thing that seems I can do. The block heaters are no good to me b/c I have no outdoor outlets.

metalz
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Post #19 by metalz » Sat Dec 03, 2005 5:10 am

There is a circulating block heater that is fired by propane. Used up north where outlets are hard to find. I realize this is a little over kill and complicated, but I thought I would let you know.

Regards

MetalZ

cjbronco

Post #20 by cjbronco » Sat Dec 03, 2005 8:39 pm

but where to buy the refill of propane? Cant do that in NJ to my knowledge. not for automotive anywayz.

metalz
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Post #21 by metalz » Mon Dec 05, 2005 5:21 pm

Use a B.B.Q. tank.

Metal Z

cjbronco

Post #22 by cjbronco » Mon Dec 05, 2005 9:59 pm

I think the easiest thing for me to do right now is to use the heated carb spacer outta a early t-bird or somthing like that. Can find it for under $50 then I guess its worth it right?

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