Dissapointing performance
- Thread starter Dusterguy
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His are 1 5/8" tubes with a 2" collector though...
Lustle
Well-Known Member
Except when they look like this:
That's his "headers". 1-5/8 tubes into 2 inch collector. Tubes are different lengths, eliminating any scavenging effect. Hi Pro 340 manifolds have a bigger collector. So yes. They are worse than headers or manifolds. In my opinion.
I dont want to start arguing with you how headers work, but I say that they dont need to be equal length. Firing order is not equal in left and right cylider banks, so making equal lenght primaries is waste of time. This info is directly from David Vizard.
Biggest problem with my headers is that primaries are too short. Collector is 2.5 not 2.0 like you said.
Biggest problem with my headers is that primaries are too short. Collector is 2.5 not 2.0 like you said.
BigBlockMopar
BigBlockMember
Someone should tell Chrysler they screwed up their exhaust on the SRT and Hellcat Hemi's making such lousy performance... ;)
Except when they look like this:
That's his "headers". 1-5/8 tubes into 2 inch collector. Tubes are different lengths, eliminating any scavenging effect. Hi Pro 340 manifolds have a bigger collector. So yes. They are worse than headers or manifolds. In my opinion.
We build custom headers. I would run these Dusterguy headers over a stock cast iron header any day.
Collector is 2.5 that tapers fast to 2. I did it that way because my exhaust size is 2". Now when I update to 2.5 exhaust pipe, I need only cut inch out of collector and weld 2.5 flange, then collector is 2.5 and exhaust pipe too.
This conversation is exhausting...
Coronet 500
Well-Known Member
Less talky, more worky!
Wouldn't it be hilarious if this keyboard warrior didn't even have a car and was sitting in his Mom's basement.
Wouldn't it be hilarious if this keyboard warrior didn't even have a car and was sitting in his Mom's basement.
Lies don't help your argument....
So are we supposed to imagine the exhaust is 2.5", the carb is a 750 DP, you have a 3k convertor and 3.55 gears too when we respond to you???
Louie70Dart
Southern IL. Complete opposite of k-town
No you didn't......
L4staero
Well-Known Member
I dont know how much of this thread got misunderstood due to the op's scandinavian way of English.
I dont see his headers being that terrible.
Ive made 375hp on a mild 318 through block huggers with a 2.5" collector.
I dont see his headers being that terrible.
Ive made 375hp on a mild 318 through block huggers with a 2.5" collector.
Lustle
Well-Known Member
I wouldn't. 1-5/8 primaries to 2 inch collector? On heads that flow enough to support 500 horse? I think between that and the manifold. It would be a wash.
So it's 2". Like I said.
As for Vizard, he's a genius and what not. Don't get me wrong. But I think you really need to study how the Otto cycle engine works. The right and left bank have nothing to do with each other if you don't have a cross over of some sort and have nothing to do with each other when headers are concerned. The idea behind headers is that exhaust gas is not "bumping" into each other as they run the exhaust. Causing back pressure. Hence the equal length. So that each exhaust "pulse" if you will travels directly behind one and in front of another. Like cars merging on the highway. That when the exhaust merge's it flows faster, allowing for scavenging. Something you really need to look into if you want to build high horse engines. Scavenging's affect on performance is huge. The cross over (whether H or X depending on style of engine) then comes into play past the headers and collectors. It also has an affect on scavenging. Allowing for one bank to help the other bank scavenge better. By allowing exhaust from the right bank to pull the left and vice versa.
But, it seems like once again you're just going to do what you want. So power to you.
Someone should tell Chrysler they screwed up their exhaust on the SRT and Hellcat Hemi's making such lousy performance... ;)
Hahaha it is lousy performance! In all actuality guys have seen gains of 40+ WHP with headers and exhaust on them. Some serious gains for something so simple. Shows that the stock exhaust definitely left room for improvement.
Yes I did...
Lars
Well-Known Member
You want to do burnouts? Do what I did, 3K stall converter, 4.10 gears, and I can do burnouts for days. This is with my 360 wheezing through small valve unported J heads with a 268XE cam.
15 pages and counting. all for some tire smoke. hum we had some traction issues with the 3 on the tree /6 dart. we took some power out and added caltracs.
Lustle that is one of the best explination of how long tube headers work
Lustle Wrote:
As for Vizard, he's a genius and what not. Don't get me wrong. But I think you really need to study how the Otto cycle engine works. The right and left bank have nothing to do with each other if you don't have a cross over of some sort and have nothing to do with each other when headers are concerned. The idea behind headers is that exhaust gas is not "bumping" into each other as they run the exhaust. Causing back pressure. Hence the equal length. So that each exhaust "pulse" if you will travels directly behind one and in front of another. Like cars merging on the highway. That when the exhaust merge's it flows faster, allowing for scavenging. Something you really need to look into if you want to build high horse engines. Scavenging's affect on performance is huge. The cross over (whether H or X depending on style of engine) then comes into play past the headers and collectors. It also has an affect on scavenging. Allowing for one bank to help the other bank scavenge better. By allowing exhaust from the right bank to pull the left and vice versa.
My 8 year old grandson could understand that!
Lustle Wrote:
As for Vizard, he's a genius and what not. Don't get me wrong. But I think you really need to study how the Otto cycle engine works. The right and left bank have nothing to do with each other if you don't have a cross over of some sort and have nothing to do with each other when headers are concerned. The idea behind headers is that exhaust gas is not "bumping" into each other as they run the exhaust. Causing back pressure. Hence the equal length. So that each exhaust "pulse" if you will travels directly behind one and in front of another. Like cars merging on the highway. That when the exhaust merge's it flows faster, allowing for scavenging. Something you really need to look into if you want to build high horse engines. Scavenging's affect on performance is huge. The cross over (whether H or X depending on style of engine) then comes into play past the headers and collectors. It also has an affect on scavenging. Allowing for one bank to help the other bank scavenge better. By allowing exhaust from the right bank to pull the left and vice versa.
My 8 year old grandson could understand that!
that's not a header, it's a exhaust manifold. I didn't say cast iron! It's all about packaging when i come to the manufacturer.Someone should tell Chrysler they screwed up their exhaust on the SRT and Hellcat Hemi's making such lousy performance... ;)
RAMM
Well-Known Member
Me too, manifolds are terrible for performance. I wonder how many guys here know the diameter of the collector on a 500ci Pro-Stock? I bet not many. J.Rob
stixx
Well-Known Member
5 inches?
racerdan80
Well-Known Member
Those headers can be made to work. They may not be as ideal as long tube headers but they are still an improvement over original manifolds. Dusterguy has already stated he will be opening up the collector to 2.5" and upgrading his exhaust to match. Then when he upgrades the carburetor and hopefully the torque convertor the tuning can begin.
You have misunderstood how headers work. How you think race cars have scavenging effect on their exhaust when they dont have collector at all? (some drag cars dont have). Im not going to tell the whole story how they work its long story, but I give you a tip that you might want to read some books like "David Vizard's How to Build Horsepower" then you might want to change that theory how headers work. This subject is out of this topic original subject and im not going to talk about it anymore.
Lustle
Well-Known Member
I've misunderstood how headers work? Yet. I'm not the one who can't even do a burnout? Uh huh....
And lots of race cars have collectors. I should know. I've worked with them. I've worked with sprint cars (sportsman, ASCS 360 and 410 Outlaws), wissota late models, dirt stock, pavement stock, pavement late model, mini and micro sprint. Guess what those guys run? Oh right. Full length headers with collectors. Heck some even run mufflers. OH I've also worked with drag cars, alcohol, top alcohol, sportsman, door slammers. You name it. So yes. I'm well aware some drag cars don't have collectors. They run "zoomies". Which BTW you will LOSE power on. Seriously. Look it up. It's well known that street engines running zoomies give up power. The only reason dragsters run them is because they are already making so much power they aren't worried about the 50hp+ (yes, it's that much). Or they are forced induction and don't worry about scavenging because the blower is forcing air through so fast there isn't any time for scavenging and its affect. The fact is that, like you said SOME race cars don't. Some. Of the highest horsepower producing engines ever made. I know a guy that put's 1930HP to the tires. Guess what he runs? Full length headers with a full exhaust. On a street legal vehicle. Last time I checked he had no problem doing burnouts. With 33x16x15 tires.
You know who does worry about scavenging? NASCAR. Yes NASCAR. They run all these neat little tests on their exhaust, X pipes and everything else. To make sure they get the most power possible. Sorry, how many race cars have you raced/worked on again?
And I also own Vizard's build hosepower book. Along with his holley books. Oh and his porting and head book. What else.... Oh I also have how to make build big inch mopar small blocks. How to hot rod small block mopars. And many many other books. I think the difference is that when I read them, I seem to understand them.
Tell you what. Obviously you were right from the start. The heads are bad. You should put the old ones back on. Send me those ones there. I'm such a nice guy I'll even pay for shipping. Laws are a little more lax over here for throwing out used car parts. So I will take care of that for you. Nice and easy. I'm just that nice.
Oh but you can keep your tip. My car does burnouts easily right now. I wouldn't want to change that.
I bellieve that you have experience in things you said. I respect your opinions but I still disagree with you how headers work.
When exhaust valve closes then there is exhaust gas traveling trought header/primaries. The inertia of gas makes low pressure/vacuum to the combustion chamber and that low pressure/vacuum suck new air/gas mixture from intake to combustion chamber. Thats most important thing how headers work/makes scavenging effect. If you are dealing with 4 cylinder engine or flat plane V8 like Ferrari, then you can take advance of primaries lenght tuning. That is another thing how headers can make scavenging effect and it works different way than what I desribled. There is also collector length tuning thing but I dont understand it enough that I could talk about it.
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