Gain extra benefits by becoming a Supporting Member Click here find out how!
Silver
Gold ***Platinum***
deek01BigDogSS (6)jk56chevy (11)WarrenL (2)Jens (10)
edad2000Custom_Deluxe_20VetteGyrl (2)JohnB (2)
speedygman (7)rickityfiftyMafo971Clifford Lao502drfleetline
Jud Leowish Non-synchronized
gary635g (6)
johnhem (10)
axmaker (3)
socalarch (3)
usmile4 (8)
Classic Performance Products Classic Parts
Ciadella Interiors American Auto Wire Art Morrison.com
Exile® Battery Keeper™ 6/12 volt charger w/ LED battery monitor
Low priced Genuine GM Auto PartsHarbor Freight
Hellwig Products IncPerformance Rod & Custom
Impala Bob's Bob's Chevy Trucks Bob's Chevelle Parts Bob's Classic Chevy

Recent Hot Topics
Current Quote
"I've gotten my money's worth many times over. I don't know how people managed to get anything figured out on their old cars before the internet.
This site's the best!"
~ Supporting Member
Recent Topics
Join the Community today







 Page 1 of 2 12
Username Post: Dyno results - headers vs rams horn manifolds        (Topic#256915)
dcairns 
Frequent Contributor
Posts: 1881
dcairns
Loc: Orange CA
Reg: 11-07-03
02-02-11 08:58 AM - Post#2040891    

I had my newly built, mild 383 run on a dyno. It is going in my 64 Impala, so good torque was important as was keeping the idle civilized enough for power brakes and air conditioning. Given those constraints and the stock block, heads and intake manifold tow work with, it came out rather well.

YouTube Video of some of the dyno runs


One of the things I wanted to test was the headers vs stock rams horns exhaust manifold topic that seems to come up from time to time. Since this engine is made of stock castings, overall breathing ability is rather limited. So the headers never really get a chance to show much advantage at the extreme top end. The rams horns are reproduction 2.5 inch manifolds that have the correct casting numbers on them. They were mildly ported and the anti-reversion bumps removed.






I have to say, that in my test conditions, using the rams horns is a no brainer. Why deal the disadvantages of headers for such a small gain?






What made a bigger impact on performance was adding the 2.5 to 2 inch reducers to the pipes, to simulate what actually happens at the muffler on the stock exhaust system on the 64 Impala. It also points out that an all 2.5 inch exhaust system would be an advantage.






And just for fun I did a run with the stock air cleaner and filter in place, along with the 2.5 to 2 inch reducers on the exhaust (trying to simulate how it will be once installed in the Impala). On a 64 Impala the air cleaner horn has a remarkably small opening and I was expecting it to really cause a hit on the performance.





Surprisingly, the air cleaner/filter had little impact. This is probably highlighting how restricted the intake manifold is. I am thinking it might be worth porting the intake a bit to pick up some more power higher up the RPM range. I don’t think a mild port would have much if any effect on idle quality, since it is a 383 breathing through a 327’s intake.



- Dave
1964 Impala 4-door sedan

_________
/ --------------- \
_/ /___________\ \_
/_________|_________\
|OOO ___________ OOO|
\______|====|______/
|_|------------------|_|




 
greg_moreira 
Very Senior Member
Posts: 3264

Reg: 10-06-03
02-02-11 09:43 AM - Post#2040909    
    In response to dcairns

Id say thats typical.

However....I'll also comment that it looks like the headears are worht about 10 FT/lbs through a large part of the rpm range(pretty consistantly around 10 all through the midrange) and 20 horsepower at peak. I think you would notice those kind of gains more than you think you would.

Realistically...this is the kind of gains seen with a cam swap up to the next size up cam in the "series"(like going from a 270 duration to a 280 duration), but with more low speed response as well. Couple hundred more rpm ability and about a 20 HP gain and mid range gains...but you also found additional low end that the manifolds didnt produce.

Its clear that the manifolds didnt kill it and will still run well and be strong, but I think that as much as this is a successful argument that a good manifold such as yours can do a good job....its also a pretty good argument for headers, that even in a mild app...its worth a noteworthy gain.

On a side note though...who knows how much the additional airflow from the headers changed carb and jetting requirements. In other words....did you jet for optimum results each time?

The gains could have either been larger yet....or actually smaller if both combinations were tweaked for max performance with the given parts you were using.

So as is...its a good argument for what a decent set of headers does even on a mild build, but it just may not be 100% apples to apples depending.

And...were these dyno headers? The operator may very well have a set fabbed up that are better than the "typical" passenger car header....so that also could lessen the gains seen with a header.

Concerning porting...yes there are large gains that can be realized. There are areas in the ports(head and manifold) that can be touched that will have virtually zero negative impact on response or idle quality, yet allow for better performance overall.






 
Rugratman 
Contributor
Posts: 461

Loc: Maryland
Reg: 09-15-10
02-02-11 10:02 AM - Post#2040917    
    In response to greg_moreira

Great Info...thanks.
doing a 383 with Horns myself.
Just Learning as I Go Here...


 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 16197
grumpyvette
Age: 66
Loc: FLORIDA USA
Reg: 03-16-01
02-02-11 12:05 PM - Post#2040985    
    In response to Rugratman

thats very impressive info,thank you for taking the time and posting your results, but I must point out, BEFORE you go thinking rams horn exhaust manifolds are almost as effective as headers,.....you need to remember that its the complete combo, not just the swap from headers from rams horn exhaust manifolds alone that can maximize the results keep in mind a great deal of what you can expect to gain from use of headers is dependent on having the exhaust headers tuned to scavenge the cylinders and thats dependent on both the header primary length , diameter,and collectors length and diameter,being correctly matched to the engines displacement, compression and cam timing, and having an exhaust system that has LESS than 1 PSI in back pressure, the best headers in the world feeding into an exhaust system with significant back pressure will result in little gains if any over a rams horn manifold.
Id also point out that when you see a dyno torque curve on a 383 sbc like that that falls rapidly from only 3500rpm, the cam used was very obviously too low in duration for the application and/or the exhaust was restrictive and hurting power (probably the case here) because theres a rapid drop in torque as the engine rpms build , thats almost always an indicator of a restricted air flow rate, it can be because the cams not allowing the intake ports to flow to their full potential but it can be because as the rpms build so does the volume of exhaust gases which increases the effect of any restricted exhaust, because of the rapid build-up in back pressure


your engines torque curve is almost always a good indication of the engine volumetric efficiency



http://forum.grumpysperformance.com/viewtopic.php?...

http://forum.grumpysperformance.com/viewtopic.php?...

http://forum.grumpysperformance.com/viewtopic.php?...

http://forum.grumpysperformance.com/viewtopic.php?...

http://forum.grumpysperformance.com/viewtopic.php?...

http://forum.grumpysperformance.com/viewtopic.php?...

" " IF YOU CAN'T SMOKE THE TIRES FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK !"


 
dcairns 
Frequent Contributor
Posts: 1881
dcairns
Loc: Orange CA
Reg: 11-07-03
02-02-11 08:30 PM - Post#2041263    
    In response to grumpyvette

Thanks for the comments. Down the road after I have recovered from the cost of this restoration, I will probably play around with a ported intake manifold and see how that compares. But first I will be running it on a chassis dyno with the engine unchanged to see what the losses are. People say it should be various percentages, but I will able to measure my own as well as get a fine tune on the carburetor. The dyno operator thought the existing jets were a bit rich, but not far off. In his opinion there was not much point in jetting it for the engine dyno, but rather it was best done on the chassis dyno.

The headers used were the dyno shop's headers, so I have no idea how well suited they were for my engine. They did look plenty large and not particularly practical in that they went straight out from the exhaust port quite a bit more than most cars would have room for. And in my case header makers have to be a bit creative to get around the X-frame design in a 64 Impala.





I guess I had the impression that headers were good for a lot more than what I saw. For my situation, where stock appearance trumps all, so headers are out of the question, and I am just pleased I am not paying too high a price to keep the exhaust looking stock. I also do not doubt headers pay off more on a more aggressive engine build, but my constraints with stock appearance and good manners limit things that can be done.

For me, the interesting thought is what the gains were in keeping the pipes at 2.5 inches, and keeping them free flowing. Changing the tail pipes and muffler to 2.5 inches would help in that regard, but I am not sure how much that would cost me in noise.


Mild cam that was used:


- Dave
1964 Impala 4-door sedan

_________
/ --------------- \
_/ /___________\ \_
/_________|_________\
|OOO ___________ OOO|
\______|====|______/
|_|------------------|_|




 
MikeB 
Senior Member
Posts: 9479
MikeB
Loc: Plano, TX
Reg: 08-28-03
02-03-11 07:06 PM - Post#2041699    
    In response to dcairns

Dave, did you play with carb jetting? That's your 300hp 327 AFB, right?

Also, you might want to consider 2.5" exhaust back to and including the mufflers, and then go out the back with 2.25" tailpipes. Much of the exhaust energy is dissipated as heat by then, so I don't think the 19% loss in area will hurt much, if any, back there. And the smaller diameter pipes are probably less restrictive than 2.5" mufflers.

One more comment: If those headers have 1-3/4" tubes, I think you'd see more torque with 1-5/8" tubes.
Real Hot Rods have a Clutch!

1955 210 2dr: 327, Brodix IK180 heads, Jones cam, M20, Wilwood front brakes

1982 C-10 SWB pickup, 250 six, 3-speed

My car pictures



Edited by MikeB on 02-03-11 07:13 PM. Reason for edit: No reason given.

 
dcairns 
Frequent Contributor
Posts: 1881
dcairns
Loc: Orange CA
Reg: 11-07-03
02-03-11 07:38 PM - Post#2041714    
    In response to MikeB

Actually we didn't change the jetting. First off, that is an AFB for a 64 409, so it is not far off out of the box. Second, the Allan figured the jetting would need to be changed again after the engine was installed with the complete exhaust. Third I had been using it on my old engine, a 350 based 383 and it was working.

Yes this whole experiment has me thinking about doing a full 2.5 inch stock exhaust. I seem to recall that the tail pipe would need to be ovaled to clear the tires. It is fairly close as it is. I would also want to see if I can find out how much that would affect noise. I really don't need more noise.

I will have to ask what size the headers were.
- Dave
1964 Impala 4-door sedan

_________
/ --------------- \
_/ /___________\ \_
/_________|_________\
|OOO ___________ OOO|
\______|====|______/
|_|------------------|_|




Edited by dcairns on 02-03-11 07:44 PM. Reason for edit: No reason given.

 
IgnitionMan 
Valued Contributor
Posts: 2713

Reg: 04-15-05
02-03-11 08:50 PM - Post#2041746    
    In response to dcairns

Header sets aren't designed correctly. To do it right, two factors need to be built into the pipes.

The head pipes should be tapered larger as they travel away from the exhaust port

There should be an anti-reversion cone set at EACH exhaust port/header flange/tube, at the flange

The dyno testing Jim Fueling and I did years ago, when we developed the anti-reversion headers for Cyclone, showed these two factors really woke headers/engines up, all the way through the rev range.

 
dcairns 
Frequent Contributor
Posts: 1881
dcairns
Loc: Orange CA
Reg: 11-07-03
02-03-11 09:15 PM - Post#2041757    
    In response to IgnitionMan

Just for fun, I took dyno data from GM archives of the 1964 Impala 327/300, the 409/425(dual quads) and my dyno data and charted them together.

I don't know how meaningful the comparison is, but it is a bit of fun. I wish I had remembered to tell the dyno operator to start recording data from lower RPMs. The old 409 sure did perform well at higher RPMs. I would think those bigger manifolds (intake and exhaust) have something to do with that. I wonder how it did once hooked up to the stock 2.5 to 2.0 inch exhaust system (same as the 327/300 of the day).




- Dave
1964 Impala 4-door sedan

_________
/ --------------- \
_/ /___________\ \_
/_________|_________\
|OOO ___________ OOO|
\______|====|______/
|_|------------------|_|




 
octanejunkie 
Contributor
Posts: 466
octanejunkie
Loc: Los Angeles area
Reg: 11-12-09
02-04-11 06:03 AM - Post#2041843    
    In response to dcairns

Interesting thread, thanks for sharing!
'59 Chevy 3100 Stepside
0.040-over 350, mild (214/224 @ .050) 112 LC cam,
vortec heads, air-gap, 600cfm carter, 2-1/2" rams horns,
built 700R4 w 2200rpm stall, 3.42 posi rear on top of 31.5" BFGs


 
rumrumm 
"13th Year" Silver Supporting Member
Posts: 1893
rumrumm
Loc: Macomb, IL
Reg: 10-18-01
02-04-11 07:31 AM - Post#2041873    
    In response to octanejunkie

Thanks for sharing--interesting comparison of headers and ram horns. As far as your last graph comparison, hp was figured differently in the 60's than it is today, so the actual figures for the 327 and 409 are probably 5-6 per cent lower.
Lynn

"There's no 12-step program for stupid."


383 sbc, Eagle, AFR, SRP, CompCams, Edelbrock, Sanderson. Dyno #'s: 450 hp @ 5700, 468 ft. lbs. torque @ 4300.

http://photo.net/photos/Lynn%20Johanso n


 
MikeB 
Senior Member
Posts: 9479
MikeB
Loc: Plano, TX
Reg: 08-28-03
02-04-11 04:09 PM - Post#2042057    
    In response to rumrumm

  • rumrumm Said:
As far as your last graph comparison, hp was figured differently in the 60's than it is today, so the actual figures for the 327 and 409 are probably 5-6 per cent lower.


Actually, a dyno run today in an engine shop is pretty much like the way the factories used to do it, which is called Gross Horsepower. That's when they dynoed engines with no air cleaner or belt drive accessories, maybe even no mufflers.

Then sometime in the early 70s they went to Net Horsepower, with all those parts installed. Seems like that was about the same time they lowered compression, so power number appeared to drop more than they actually did.

Maybe I-man can chime in here.
Real Hot Rods have a Clutch!

1955 210 2dr: 327, Brodix IK180 heads, Jones cam, M20, Wilwood front brakes

1982 C-10 SWB pickup, 250 six, 3-speed

My car pictures



 
64cv 
"6th Year" Silver Supporting Member
Posts: 716
64cv
Reg: 06-05-08
02-04-11 08:00 PM - Post#2042146    
    In response to dcairns

Dave,

Thanks for posting all this stuff; it's really rare. Not too many people spend the time comparing the stock manifolds with headers.

Brad
Life is an optimization problem; make the most of it!

'64 Impala Convertible, Blueprint 383, Tremec TKO 5sp, 4-wheel disc brakes.


 
HAL_396 
Member
Posts: 2944
HAL_396
Loc: Austin, TX
Reg: 11-16-06
02-04-11 08:35 PM - Post#2042160    
    In response to 64cv

I put 2.5 rams horns on my engine just so I wouldn't have the hassle of dealing with headers. I haven't had one issue since I installed them in 07.

Of course this is on a street driven car. Headers will be installed on my track cars when the time comes.
1955 Chevy Custom
1966 Biscayne
1966 Caprice Drag Car Inwork
1966 Caprice parts car
2004 Silverado
2007 Impala LS
2009 G5


 
dcairns 
Frequent Contributor
Posts: 1881
dcairns
Loc: Orange CA
Reg: 11-07-03
02-04-11 09:26 PM - Post#2042181    
    In response to 64cv

  • 64cv Said:
Dave,

Thanks for posting all this stuff; it's really rare. Not too many people spend the time comparing the stock manifolds with headers.

Brad



One of the frustrating things about learning about engine performance is how much people rely on "seat of the pants" and "bigger must be better" or "what some performance guru said". Not to put down the people who through years of experience know just what to do. Those are the folks who have the real knowledge, it just makes it harder for me to learn when there are no facts and figures attached. Just the way my head works I guess.


- Dave
1964 Impala 4-door sedan

_________
/ --------------- \
_/ /___________\ \_
/_________|_________\
|OOO ___________ OOO|
\______|====|______/
|_|------------------|_|




 
IgnitionMan 
Valued Contributor
Posts: 2713

Reg: 04-15-05
02-04-11 10:27 PM - Post#2042197    
    In response to dcairns

Both Ford and Pontiac used cast iron "headers", heavy, but, they dampened the harmonics inside the head pipes, and retained consistent heat all the way down the "tubes", and, that helped a lot.

A lot of people that claim they are saavy about stuff, just ain't, like those who build steel tubing headers, then state that the heats needed to keep the exhaust parameters working the right way, aren't important in any way.

When we did the two stroke expansion chambers, we found that they ran too cold to keep the harmonics right, and had to wrap them with heat wrapping to get them to work right. Same happens to steel tube header tubes, they run too cold, the header system doesn't work right. We even messed around with water jackets around the head pipes on some applications, with as hot a water inside that system as we could get.

On a separate note, earlier today, I went into town to do some errands, and one of our local disaster car (farm implement, hammer, chisel) shops had moved to the front of the building they were in, and set up a showroom, what a hoot. Anyway, they have a Chevy small block of some kind on an engine stand in the showroom, and, it has a Deadbroke Air Gap manifold on it. I took a really close look at the setup, and saw just how problematic adding a water stove under the plenum would be. There is room for one, but, it'd have to be square tubing, if the two supports for the valley pan weren't removed.

A stop gap way to get some heat into the plenum would be to use some closed cell foam, as others now do, and stuff all the open areas closed with the foam, but, letting the area just under the plenum remain open. There would be the opening under the water transfer/thermostat housing, the area just behind it, and the two open areas on either side of the plenum area to head sealing rail that would need stuffing closed.

I better understand now, just why the air gap stuff doesn't work well on the street, and at lower speeds, the things just run too cold for sustained street operation, FINE for a 1/4 mile run, but, NOT ON THE STREET WITHOUT SOME SORT OF HEAT IN THE PLENUM, and, optimally, in the runners as well, but, that isn't really practical.

Edited by IgnitionMan on 02-04-11 10:34 PM. Reason for edit: No reason given.

 
MikeB 
Senior Member
Posts: 9479
MikeB
Loc: Plano, TX
Reg: 08-28-03
02-05-11 06:58 AM - Post#2042263    
    In response to dcairns

  • dcairns Said:
One of the frustrating things about learning about engine performance is how much people rely on "seat of the pants" and "bigger must be better" or "what some performance guru said".


One of my favorites is the old wives tale that a car will accelerate faster if you can feel the vacuum secondaries kick in. Holley says all you're actually feeling is a momentary bog, which means they're opening too soon.

Another is Harvey Crane saying something like "My customers always seem to want a bigger cam than their engines do."
Real Hot Rods have a Clutch!

1955 210 2dr: 327, Brodix IK180 heads, Jones cam, M20, Wilwood front brakes

1982 C-10 SWB pickup, 250 six, 3-speed

My car pictures



Edited by MikeB on 02-05-11 07:09 AM. Reason for edit: No reason given.

 
Pistol 
"12th Year" Silver Supporting Member
Posts: 3654
Pistol
Age: 68
Loc: Terryville, Ct.
Reg: 11-11-02
02-05-11 03:38 PM - Post#2042423    
    In response to IgnitionMan

  • Quote:
I better understand now, just why the air gap stuff doesn't work well on the street, and at lower speeds, the things just run too cold for sustained street operation, FINE for a 1/4 mile run, but, NOT ON THE STREET WITHOUT SOME SORT OF HEAT IN THE PLENUM, and, optimally, in the runners as well, but, that isn't really practical



So what your saying is that a air-gap manifold is a waste of aluminum, what would you feel is a better manifold for the street?
Pete
Awl speeling misteaks r myn
57 BelAir 2DRHT My-Pics


 
Brian HHP 
None
Posts: 977

Age: 38
Reg: 12-24-10
02-05-11 04:21 PM - Post#2042430    
    In response to Pistol

IMHO the Performer RPM would be a better choice for a Gen 1 smallblock.
Project Sublime - 00' Dodge Dakota, 355/4L60E swap
Co-owner and Engine builder for HHP


 
IgnitionMan 
Valued Contributor
Posts: 2713

Reg: 04-15-05
02-05-11 07:26 PM - Post#2042527    
    In response to Brian HHP

NOPE, the air gap style has its place, but, unless the plenum and runners are heated somewhat, utterly useless for daily driver and/or street use. Warm it up, with WATER HEATING, and it'll work a whole LOT better.

 
Brian HHP 
None
Posts: 977

Age: 38
Reg: 12-24-10
02-05-11 07:29 PM - Post#2042529    
    In response to IgnitionMan

  • IgnitionMan Said:
NOPE, the air gap style has its place, but, unless the plenum and runners are heated somewhat, utterly useless for daily driver and/or street use. Warm it up, with WATER HEATING, and it'll work a whole LOT better.



Keep in mind this only applies to carb'ed or TBI engines.
Project Sublime - 00' Dodge Dakota, 355/4L60E swap
Co-owner and Engine builder for HHP


 
IgnitionMan 
Valued Contributor
Posts: 2713

Reg: 04-15-05
02-05-11 07:53 PM - Post#2042538    
    In response to Brian HHP

Let's see, I( work on a LOT of the old Buick all aluminum 215, and later Rover 4.0/4.6 all aluminum engines, both EFI and carb. They all have divorced plenums, or, AIR GAP types. They ALL use heated engine coolant (water) to heat the plenums, and runners, and all of them work very well.

One older manifold that there aren't too many of for these engines is the Huffaker single plane manifolds, with fully isolated plenum and runners. These manifolds work well IN ROAD RACING APPLICATIONS ONLY, and, miserably in street use, NOT because they are single plane, gut that they run STONE COLD, NO heat of any form.

And, EVERY EFI setup I have seen uses some sort of heat, usually water from the "cooling" system, to HEAT the throttle body/air plenum/runners, to stop icing up of the system air inlet.

I ran a Holley throttle body EFI setup on my 1972 Vega with 310 cu/in, EFI, 5 speed street car. I learned the hard way that the throttle body and plenum DEMANDED some form of heat to work, not just properly, but not freeze the throttle plates. I found the icing when I modified the top of a regular air filter with a large hole, and clear plastic insert that held the cleaner down, and literally looked down through the plastic, observed the icing for myself. The first time I saw the icing was in July, in Southern California, on a 102 degree/F. day, idling, as the engine warned up. What was significant was, the icing didn't go away after the engine was fully warm. Installing a water heated carb spacer stopped the icing, and the engine ran a whole lot better.

 
Brian HHP 
None
Posts: 977

Age: 38
Reg: 12-24-10
02-05-11 08:00 PM - Post#2042542    
    In response to IgnitionMan

You are talking about factory EFI manifolds that are required to work in -25 temps all the way up. But, for 90% of engines out there, it's simply not needed. The proof is in the number of late model EFI engines that perform just as well with the TB coolant portion bypassed and even pick up HP (the LT1/LT4 engines are another example of this as bypassing the TB coolant ports drops air charge temps by several degrees and therefore making more power).

While with TBI EFI systems I would agree, with something say as a LT1 with a single plane manifold, it's simply not needed as the fuel and air mixture is heated enough by the heat in the cylinder heads. Which is why I said carb'ed and TBi setups still need it. It is why the LS1 guys can run large high-rise single plane intakes and daily drive them with zero issues.

MPFI setups do NOT need the heated plenums/TB's like carb'ed and TBI setups do.

Hence another reason TBI is an inefficient and outdated form of fuel delivery on anything but mundane family cars, but that's another topic.
Project Sublime - 00' Dodge Dakota, 355/4L60E swap
Co-owner and Engine builder for HHP


Edited by 98Z714X4 on 02-05-11 08:03 PM. Reason for edit: No reason given.

 
greg_moreira 
Very Senior Member
Posts: 3264

Reg: 10-06-03
02-05-11 08:35 PM - Post#2042552    
    In response to IgnitionMan

  • IgnitionMan Said:
NOPE, the air gap style has its place, but, unless the plenum and runners are heated somewhat, utterly useless for daily driver and/or street use. Warm it up, with WATER HEATING, and it'll work a whole LOT better.



Just a clarification. The performer rpm(as mentioned in the thread right before this) does not have an air gap. The one that does is actually specifically named the "performer rpm airgap".

Just wanted to eliminate confusion.

Pete had asked if you are stating the air gap is a bad manifold for the street.

Then 98Z714X4 responded stating the performer rpm is the better choice for a gen 1 engine on the street. This would actually be the non airgap manifold(as I read it), which goes hand in hand with what you're saying Iman.

And I too agree that the non airgap(regular performer rpm) is the better choice.

FYI we tried the airgap performer rpm when it was pretty new. Put it on a 68 chevelle with a 355 small block running in the 12.6 to 12.8 range on the 1/4.

It did run a little better at the race track. You would never notice a seat of the pants difference, and the difference at the track was only minimal too(which may or may not be worth it to you). But it was harder on the street. In western pa we only get about 2 months of really hot weather(90 plus) all year. Thats about the only time it was nice to drive.

In any mild or cooler weather...it was harder to start all the time and didnt run as smooth for a long long while. Eventually everyything would heat soak enough that it would smooth out and idle/cruise well, but you had to log a good few miles before you got enough heat in it that it wasnt acting like you just cold started it and hopped in and tried to drive.

With the weather we have around here, I basically decided it would never be worth it for me to use one again on a driver.

 
Brian HHP 
None
Posts: 977

Age: 38
Reg: 12-24-10
02-05-11 08:38 PM - Post#2042553    
    In response to greg_moreira

Thanks Greg, I guess I should have noted I meant the classic RPM not the air gap.
Project Sublime - 00' Dodge Dakota, 355/4L60E swap
Co-owner and Engine builder for HHP


 
C10 Sleeper 
Valued Contributor
Posts: 3426
C10 Sleeper
Loc: Redding Ca
Reg: 03-17-09
02-05-11 09:45 PM - Post#2042574    
    In response to Brian HHP

I agree with Greg. I used an air gap weiand manifold that caused me nothing but headaches on the street. The same motor in the same heavy truck previously used a Victor Jr. I know some of the people on here will say a single plane on the street is a big fat no no and throw in a heavy 5000 pound truck and you are especially violating the paper pushers rules.

With the Vic Jr I might have been giving up a little low end. But it still smoked the tires at will up to about a 60 MPH rolling start so giving up a little low end wasn't noticeable. Either way I never had a problem until I switched to the air gap.

I believe the manufacturers and magazines promote these manifolds with half the truth in their stories. They make it out to be a miracle manifold that works on the street as well as on the strip where it works best. If you want a street manifold I suggest staying away from the air gap design.

I know the Vic Jr has a gap and worked well for me but why? I'm guessing it has something to do with the same reason a dual plane will need more carb than a single plane in the same application.
http://photobucket.com/C10Pictures


 
Brian HHP 
None
Posts: 977

Age: 38
Reg: 12-24-10
02-05-11 09:54 PM - Post#2042578    
    In response to C10 Sleeper

I think those that complain the most about using a single plane on the street are the ones who slap it on their engine changing nothing else, then whine about the loss of bottom end torque etc etc. With the right supporting modifications a single plane will work just as well on the street. I think a big part of it is guys are used to hearing things, and thinking it still holds true, look how many guys honestly believe a set of junk double hump heads are actually performance heads? One good thing with the newer Gen 3 engines is this whole argument is dead as they lose absolutely nothing using a monster single plane on the street versus a traditional street manifold.
Project Sublime - 00' Dodge Dakota, 355/4L60E swap
Co-owner and Engine builder for HHP


 
IgnitionMan 
Valued Contributor
Posts: 2713

Reg: 04-15-05
02-06-11 04:21 PM - Post#2042879    
    In response to Brian HHP

NOPE again, I am speaking about sonic air speeds past closed throttle plates, and the icing that occurs in ALL EFI manifold setups,. not your incorrect 90 whatever percent.

If YOU want the thing to run like dog, by all means, do it the way YOU wish, but, I prefer to do it the way it works RIGHT, not cob'd up under some tree in the back yard, and cold.

NOBODY, including me, is forcing anyone to do it right, if YOU don't want heat in the manifold, by all means, don't heat it, and suffer the consequences, you got what you wanted.

Same thing goes for headers vs cast iron exhaust manifolds, do it any way you like, but, there is a right way to do it, and the rest of the ways. I prefer to do it the right way.

Edited by IgnitionMan on 02-06-11 04:23 PM. Reason for edit: No reason given.

 
C10 Sleeper 
Valued Contributor
Posts: 3426
C10 Sleeper
Loc: Redding Ca
Reg: 03-17-09
02-06-11 06:07 PM - Post#2042910    
    In response to IgnitionMan

What is the right way to use headers? My next upgrade is an exhaust system including a set of long tube headers. If I can do it right the first time and get the most gain for my dollars I'm willing to try almost anything.

As far as my experience with the air gap manifold I didn't know anything about making a heater until it was gone. I don't know much and I learn as I go. I also really like reading ignitionmans responses and have learned a great deal from reading his do it right philosophy. I have benefited from his ignition advice and surely would have had better luck with the air gap manifold if I still had it after his advice. Now I am curious to hear some pointers about headers before starting my exhaust project.
http://photobucket.com/C10Pictures


 
Brian HHP 
None
Posts: 977

Age: 38
Reg: 12-24-10
02-06-11 08:24 PM - Post#2042972    
    In response to IgnitionMan

  • IgnitionMan Said:
NOPE again, I am speaking about sonic air speeds past closed throttle plates, and the icing that occurs in ALL EFI manifold setups,. not your incorrect 90 whatever percent.

If YOU want the thing to run like dog, by all means, do it the way YOU wish, but, I prefer to do it the way it works RIGHT, not cob'd up under some tree in the back yard, and cold.

NOBODY, including me, is forcing anyone to do it right, if YOU don't want heat in the manifold, by all means, don't heat it, and suffer the consequences, you got what you wanted.

Same thing goes for headers vs cast iron exhaust manifolds, do it any way you like, but, there is a right way to do it, and the rest of the ways. I prefer to do it the right way.



Well someone should go tell the thousands of guys over on LS1tech running non-heated single planes they are all wrong and that they are only thinking their engines run great.

Sorry, but your argument just doesn't stand, I don't really care what your experience with old school carbs and doggy TBI engines tell you. If TB icing was such an issue as you claim, it would be prevalent, or even an issue, which it isn't.

I respect your knowledge, but you're not the end all be all final word on the subject and practical real world experience proves you're wrong on modern EFI setups.

Unless you can show me otherwise with PROOF versus you talking down to those who disagree with you like you're jesus and we're the unwashed masses which has been your tactic for years when anyone disagrees with you.

As for cob'ed together, I can show you several guys running low 9's on the street that will be glad to beg to differ.


Project Sublime - 00' Dodge Dakota, 355/4L60E swap
Co-owner and Engine builder for HHP


Edited by 98Z714X4 on 02-06-11 08:30 PM. Reason for edit: No reason given.

 
 Page 1 of 2 12
Icon Legend Permissions Topic Options
Report Post

Quote Post

Quick Reply

Print Topic

Email Topic

21482 Views
FusionBB
FusionBB™ Version 2.1
©2003-2006 InteractivePHP, Inc.
Execution time: 0.148 seconds.   Total Queries: 17   Zlib Compression is on.
All times are (GMT -0800) Pacific. Current time is 12:40 PM
Top