Are headers worth it???? (2 Viewers)

[Perfect Obsession]

[quote author=Rice link=board=1;threadid=8866;start=msg76920#msg76920 date=1071685045]
...So someone putting internal mods into a SBC (heads, valves, intake, cam, carb) is not realizing the potential of those additions if they don't run headers ... in that case you can find it costing more than 30 or 40 HP (i.e. ~10%) for the average street engine. For an engine such as a F/2F the gains are much smaller.

The hot air condition is still the same. Sucking hot air into an engine will cost both torque and HP. Always find a way to pull air from outside. Otherwise the addition of a nice carb can be undermined by where the air comes from.
[/quote]

I agree with your comments.

Just to quantify your comments, I runned some simulation sequences witth a sophiticated engine simulation software. Starting with 2F specs and similar torque/HP curvature from 1000 to 3800 rpm range, I got:

- Calibrated header (two separated lenghtly three-to-one headers) increases torque by 2% over the full range with possibility to over the engine since the max HP rev is higher. If you drag racing that's good but ...

- Intake Fresh not-heated air (instead of production-type heating)s increase the volumetric efficiency and, trerefore, the torque by 8% over the full range, particularly noticeable in the low-end part.

- Increase intake and/or exhaust CFM, by as much as possible, increase the torque only at high rev (noticeable over 2500 rpm) compare to stock system.

- Calibrated intake manifold (similar to 4runner: tuned-ram primary with plenum) increases so much that it was too beautifull to believe but the tuned-ram length was prohibitively long to increase volumetric efficiency at 1800 rpm.

Note #1: For an identical targetted rpm, considering exhaust/air sound speed ratio at about 550/350 (metric system!) and intake/exhaust valve durations about the same, the intake ram length should be 11/7 times the exhaust primary length and therefore to 49 inches header correspond 77 inches primary ram. Therefore, well tuned intake ram shall use upper harmonics to reside under the stock hood.

Note #2: These tries was for personal experiences and these should not be interpreted and/or used to conlude truth.

But, IMHO, I would say that next modification my Fiji will experience is breath fresh cold air. Take a deep breath!

 

[drohweder]

IDave:
Guess since Fords are a piece of s$*t then driving one might help one to do the same ! Lactulose! Have you ever tasted that stuff? Kinda cruel to expect people to drink that nastiness! I tried it once just to help me be "empathetic" with others-lesson learned, my rx pad now has an empathy bypass circuit . jk

 

[drohweder]

Sorry fellas, that wasn't appropriate for the tech section. "click" empathy switch back off. I'm out.

 

[IDave]

P.O.
If I follow you correctly, the hot air/ cold air issue is paramount. My 71 F engine's stock air cleaner takes air right out of the front of the engine compartment next to the radiator. What do you think about the effect of insulating the air cleaner from the engine compartment as well as a simple extension to the very front of the compartment? Maybe worthwhile?

Dan,
There is only so much empathy to be dispensed. Lactulose trials mean nothing for those who have no indication. Better to test it out on inlaws who are FOS.

 

[drohweder]

Good thought! I actually may try to sneak it to some other residents while on a call night !! Oh yea, I am going to make some friends.

 

[IDave]

Yeah, well, who will end up doing their work when they go home "sick"?

(Yes, this is a technical LC question).

 

[Pin_Head]

[quote author=DenverCruiser link=board=1;threadid=8866;start=msg76888#msg76888 date=1071678520]
How exactly does a ignition kit give you more power? I am assuming it sends more power to the spark plug but I wouldn’t think that this would create that much better of a combustion. ??
[/quote]

It doesn't.

I'm not trying to be contrary, but years of experience with street racing during my formative years showed me that ignitions by themselves have no effect on power when you measure it objectively on a dynomometer or in your 1/4 mile times. The way it works is that if you increase the compression, the fuel/air charge and the operating RPM, then you need a high performance ingition to reliably ignite the charge, but you are not going to encounter this sitation in a stock 2F.

If you are replacing a worn out, malfunctioning distributor with one that works properly, then yes, you will notice a performance gain, but this is not related to the different ignitions per se. That doesn't mean that electronic ignitions aren't good: They are very reliable.

Save your money if your distributor is good.



The cost effective way of getting a real performance increase is to swap in a 350 TBI or TPI.

 

[Poser]

Pin head:

I must respectfully disagree.

If you take out a points ignition system, and replace it with an HEI unit, you will burn more fuel, period.

On my Land Cruiser, I could not get over 30 MPH with my 2F and 42's at five-to eight psi. Changing nothing other than removing the Non-USA vac advance points ditrib, and installing a DUI unit, gapping the plugs to .055" as per the instructions, I am able to drive at any speed and accelerate, even going up hill. 15x42x15 swampers aired down, rob a substantial amount of power from any engine.

Somewhere, somehow, that HEI unit, providing more spark, is making more power, period.

I know of two other 2F powered 40's running 38.5x14.50's, and one using 36x12.50 SX Swampers, who all claim the same thing, a massive increase in power.


But hey, perhaps these are isolated cases that are outside the realm of reality, and are providing results that are not typical..

Good luck!

-Steve

 

[IDave]

Steve,
Did you seem to be running rich: carboned up tailpipe, anything to suggest that before the DUI you were incompletely combusting?

 

[Poser]

[quote author=IDave link=board=1;threadid=8866;start=msg77544#msg77544 date=1071794025]
Steve,
Did you seem to be running rich: carboned up tailpipe, anything to suggest that before the DUI you were incompletely combusting?
[/quote]

I am fairly certian that it was a little, but even when installed on a vehicle that wasnt, there was a significant gain in power, you can feel it in your ass, so near as I can figure, if you put more spark into a hole, and really burn all the fuel that is in there, you are going to make more power. Color me crazy, but I think that it makes sense...

-Steve

 

[IDave]

Well, that's the only thing that makes sense to me, too. SO, doesn't that also suggest that the DUI corrects for either: imperfect timing, or, imperfect mixture, or low current. If so, then, are there other ways of doing the same thing?

 

[Pin_Head]

[quote author=Poser link=board=1;threadid=8866;start=msg77539#msg77539 date=1071793228]
Pin head:

I must respectfully disagree.

If you take out a points ignition system, and replace it with an HEI unit, you will burn more fuel, period.

On my Land Cruiser, I could not get over 30 MPH with my 2F and 42's at five-to eight psi.
Somewhere, somehow, that HEI unit, providing more spark, is making more power, period.

-Steve
[/quote]

Maybe you had a bad distributor?

There is no such thing as more spark; either it sparks or it doesn't.

Put it on a dyno before and after and then we can talk.

 

[Poser]

There is always more than one way to skin a cat Dave.

What would you suggest as remedies to these?

 

[Poser]

[quote author=Pin_Head link=board=1;threadid=8866;start=msg77576#msg77576 date=1071798104]

There is no such thing as more spark; either it sparks or it doesn't.

[/quote]


Please explain for the thinking impared...


A more powerfull spark does not equate to anything? Then what is the reason for increasing the gap on a HEI plug over a point system? What was the reason to go to that system in the first place? Certinaly could not be reliability, because there are many magnetos operating not only aircraft engines, but many older tractors, and pony engines, and they are points.

I only have the on and off road time in the truck, both with points, and with the HEI, and noticed a marked improvment. I do not have accsess to a dyno, and it really is nothing that I feel I need to spend the cash on right now. It is not that big of a deal to me. I just know that it made a real difference in the performance of my 2F. Was the distributor bad? I do not think so. That piece was only nine years old, and was new on install.
Bad coil? Ran too well for that. Bad points? Ran too well for that.


Please share some of that knowledge.

-Steve

 

[Perfect Obsession]

[quote author=IDave link=board=1;threadid=8866;start=msg77572#msg77572 date=1071797317]
Well, that's the only thing that makes sense to me, too. SO, doesn't that also suggest that the DUI corrects for either: imperfect timing, or, imperfect mixture, or low current. If so, then, are there other ways of doing the same thing?
[/quote]
Out of others malfunctions, I would suggest that thermal primary and secondary effects could perturbate non-electronic distributor. Just the pickup coil is advantageous, IMHO. I am not suggesting that pickup coil, at 2F rev range, increases engine power, just that pickup coil is steadily reliable. Period.

[quote author=IDave link=board=1;threadid=8866;start=msg77426#msg77426 date=1071777776]
P.O., If I follow you correctly, the hot air/ cold air issue is paramount. My 71 F engine's stock air cleaner takes air right out of the front of the engine compartment next to the radiator. What do you think about the effect of insulating the air cleaner from the engine compartment as well as a simple extension to the very front of the compartment? Maybe worthwhile?
[/quote]
I don't know where is McCall, ID, is it cold or not, but... Is your '71 have better low-end torque when breathing cold air (engine near operating temperature with cold radiator)? I point out low-end torque since, upon the simulation, at idle, the 2F volumetric efficiency is about 60% and more easily increased with fresh cold air.

What is the air path?
a) When cold, my Fiji takes air near the manifold exhaust to heat it up and facilitate combustion.
b) When hot, it takes air near the wheel well, under the hood .
c) In both cases, air goes through the air filter "cabinet" (over the engine in my case, and therefore heated by the valve cover)
d) Then, pass throught the carburator (which is heated up by the exhaust manifold upto a certain degree upon exhaust temperature via external thermo-spring control)
e) Then reach the cylinder via the exhaust-heated intake manifold. :-\

Your question: Is it good to cool "b" and "c"?
IMHO, "d" and "e" will continue to heat breathed air but the carb and manifold shall cooldown when colder air from "b" and "c" will go in. Like your question suggest and my simulations tend to conclude, I will, personnally, install intake extension (snorkel-like) and air-filter "cabinet" insulation, expecting a noticeable increase of engine volumetric efficiency.

On an other hand, header installation (the thread subject here) shall permit to install a heating plate under the intake manifold which shall be more controlable (manually or not) than the external thermo-spring control. This control shall permit to cooldown operating temperatures of "d" and "e". That's good ! Really good !

 

[IDave]

Steve, I don't know much about the Davis Unified system. I know those who sell it for the Chrysler say it increases horsepower substantially, and that the current is more than a standard coil produces. But I don't really understand how that is connected. How it works. It seems that once the gas is ignited, given a certain amount of fuel and oxygen in the correct proportions, the whole shebang should ignite. Either there is enough spark to ignite, as Pin_Head sez, or there isn't. A chain reaction occurs. And, either the ignition occurs at the right point of the engine cycle, or it doesn't. So once past a threshhold, more current won't cause more fuel/oxygen vapor to explode and release more energy.

I am not questioning your experience. I agree that it seems to be accepted that DUI will do the things you say. But I don't know enough to understand the why, and I was hoping someone could explain it to me.

 

[Pin_Head]

[quote author=Poser link=board=1;threadid=8866;start=msg77585#msg77585 date=1071799762]
Please explain for the thinking impared...


A more powerfull spark does not equate to anything? Then what is the reason for increasing the gap on a HEI plug over a point system?
-Steve
[/quote]

The spark isn't more powerful. The things that determine the spark voltage (and therefore energy) are: The compression, the air/fuel charge and the spark plug gap.

Having a high voltage ignition means that you can run a larger gap and therefore a higher voltage at the gap, but this doesn't mean spit for the amount of energy released. The reason is simple: The spark energy is .000001% of the energy that the burning fuel releases and the energy for the spark comes ultimately from the engine turning and generating electricity. Once you initiate the fuel burning you get the same amount of energy released no matter what the intensity of the spark.

The reason that all engines use electronic ignitions is that they are more reliable and lower maintenence, which is a good enough reason to have one.

They don't increase power or performance in the absence of putting more air/fuel mix in the cylinder.

When you increase the compression or the amount of air/fuel mix (like with turbo or super sharging) it requires a higher voltage to produce the spark to ignite it.

 

[IDave]

Bon Soir, PO
I believe I have followed what you said. One of the issues you bring up is the heating plate under the intake in the situation of headers. I have a "liquid heat riser" under my current header system. There is, of course, no way to turn it off the way it is set up. While I see that it would modulate the temperature somewhat, it seems that maybe a coil activated heatriser like the OEM would be a better method. Unless you have a way to switch off the liquid heatriser once the engine is warmed up, while it speeds warmup, it may also maintain higher temps at the carb once warmup has occured. Is that not so? Therefore, a properly functioning coil controlled heatriser, or a switched electric heatriser, plus the intake of colder outside air to cool the carb should improve the power the most efficiently. Do I understand correctly?

On the other note, I think you answered my question to Steve: the DUI provides more reliable, consistant current, thus there is less "missing" over the RPM range, thus more power. Correct?

McCall is cold right now. 10 degrees F in morning, 20 degrees F late afternoon. In the summer, 40 degrees morning, 70-80 degrees afternoon.

 

[Poser]

HI-JACK....HEI, SPARK, FUEL, and other fun stuff!!

Since this is now a complete HI-JACK-


How does incomplete combustion figure into any of this, ie, "running rich"?

And, if you do have incomplete combustion, what are the causes, and remedies?

Thanks!

-Steve

 

[Pin_Head]

Incomplete combustion is caused by having excess fuel for the air in the cylinder (eg "rich") such that the combustions products stop at CO (carbon monoxide) and do not get fully oxidized to CO2. The solution is to have your carb jetted correctly and running properly.