پروژه ساخت هدرز دست ساز
پارامتر های مورد نیاز در ساخت هدرز :
Total Number Of Cylinders in the Engine
Cylinder Bore Diameter .
Stroke Length .
Engine Performance Specifications
Compression Ratio
Peak Engine Horsepower Measured at the Flywheel
Engine RPM at Peak Horsepower
Performance Factor
Exhaust System Characteristics
Exhaust Port Length in Cylinder Head in.
No. of Collected Primary Pipes in One header
با استفاده از همین نرم افزار به این اعداد میرسیم :
همونطور که از پارامترها مشخصه با پرفورمنس فاکتور 4، که روی قدرت در دورهای میانی تکیه داره و با اینحال خیلی هم از قدرت در دورهای بالا کم نمیکنه (دقیقا چیزی که شما دنبالش بودید) مشخصات از این قراره:
- هدرز 4 به 1
- طول لوله های اصلی، یعنی همون لوله هایی که به سر سیلندر متصل میشوند : 91 سانتی متر
- قطر داخلی لوله های اصلی، 3 سانتی متر
- قطر داخلی کالتور: 4.7 سانتی متر (یعنی قطر لوله ای که از جمع شدن 4 تو لوله اولیه بدست میاد)
- طول کالکتور: 33 سانتی متر
از اونجایی که لوله استیل با اون قطر پیدا نخواهی کرد، نزدیکترین قطر داخلی لوله های اصلیت خواهد بود 1 اینچ و نزدیکترین قطر داخلی لوله کالکتورت خواهد بود 1.5 اینچ.
بر اساس پیشنهاد نرم افزار در عوض هر 1/8 اینچ افزایش در قطر لوله ها، 1.5 اینچ به طول لوله باید اضافه گردد
بنابراین طول جدید لوله های اصلی خواهند بود: 86 سانتی متر
و به همین ترتیب طول جدید لوله کالکتورت خواهد بود: 28 سانتی متر
برای درک بیشتر موضوع از تصویر زیر استفاده کن:
لطفا قبل از شروع کار حتما نکات زیر رو بخون، ایده های بسیار خوبی بهت میدن:
[align=left]PRIMARY HEADER PIPES
1. Select an available primary header pipe size (inside diameter) closest to the value calculated by the Header Design Program. Use the Gauge of Steel Thickness Table to help calculate outside diameters, since pipes are sized by outside diameter. If the optimum size is halfway between standard pipe sizes, always select the smaller size pipe if part-throttle operation and throttle response are important. Select the larger size for racing.
2. Select or build primary header pipes to the length calculated by the Header Design Program. As a general rule, the primary pipe length tolerance should be as follows: +/- 0.5inch for primary header pipes less than 30 inches long, +/- 1inch for primary header pipes 30 to 40 inches long, +/- 1.5inches for primary header pipes over 40 inches long.
3. The primary header pipe length given by the program should be lengthened 1.5” for every 1/8” in diameter that the header pipe is oversized.
4. Match primary header pipes to exhaust ports in both shape and trajectory.
5. Use similar large radius bends for each primary header pipe. Avoid sharp bends near the exhaust port, if possible.
COLLECTOR REDUCER & COLLECTOR BODY
1. The overall length of the collector reducer (cone) and collector body should equal the collector length output value given by the Header Design program. If your primary header pipe lengths are too short, you should lengthen the collector to compensate.
2. The collector length given by the program should be lengthened 1” for every 1/4” in diameter that the collector pipe is oversized.
3. Select a collector body inside diameter based on the value calculated by the Header Design Program. Try to keep the ratio of the inside area of one primary pipe to the inside area of the collector body the same as that calculated by the Header Design Program.
4. If the optimum collector size is halfway between standard pipe sizes, always select the larger size collector pipe for 4-into-1 V8 headers, and 5-into-1 headers.
5. Running 6 or more primary pipes into a single collector is not recommended. Arrange primary pipes by firing order into pairs of 3-into-1 headers on I-6 and V12 engines. The specified collector body diameter will be flowing near capacity for I-5 and V10 engines with 5-into-1 headers, and for V8 engines with 4-into-1 headers.
6. Buy or make a collector cone that fits between the ends of the primary header pipes and the collector body. This piece should snugly fit the perimeter of the primary header pipes to promote smooth flow into the collector. Use a maximum 20degree reduction cone included angle.
7. If the design collector length proves to be too short to fit a particular application, as might be the case for small displacement high RPM engines, a tapered collector design should be used. This design will be done on an individual basis.
8. The collector can be lengthened beyond the value calculated by the Header Design Program. Some engines benefit at all RPM by lengthening the collector 1 to 2 inches.
9. As additional length is added to the collector, the engine’s torque curve will change shape and upper RPM power will generally decline. Optimum collector lengths determined by experimentation seldom exceed 24”, so test for low ET with length increases of 2” at a time.
H-PIPES, Y-PIPES, X-PIPES AND TAILPIPES
1. An H-pipe, X-pipe or Y-pipe must be used to connect the collector outlets of multiple headers on an engine when tailpipes are used. Locate the H-pipe just beyond the calculated length of the collectors. Size the H-pipe the same diameter as the collectors, and keep it as short as physically possible . Locate the junction of a Y-pipe or X-pipe at the end of the collectors as well. The change in area created at the end of the collector is very important to proper header function when open headers can’t be used.
2. The collector outlet on I-4 and I-5 engines, with 4-into-1 and 5-into-1 headers respectively, must empty into a purge chamber or race muffler body upstream of the tailpipe when an open header can’t be used. Use a chamber size of 8 to 10 single cylinder displacements. A long collector/tailpipe combination is not compatible with the Header Design Program, and may not provide optimum scavenging at any engine speed.
3. The combined cross-sectional area of tailpipes on an engine should not exceed the combined cross-sectional area of primary header pipes, even for race engines. For light-throttle economy applications this ratio should be about 45%. For street performance cars this ratio should be about 50%. For street-strip applications, this ratio should be about 60%.
4. High-flow catalytic converters and mufflers are available today that produce virtually no backpressure in the exhaust system if properly selected. The small amount of backpressure these modern units produce is of negligible magnitude when compared to the magnitude of the waves in the header. Avoid sudden changes in tailpipe area at the connections to cats and mufflers.
WHEN TO USE A STEPPED-TUBE HEADER
A stepped-tube header can be made by using one primary header pipe size near the exhaust port, and the next larger pipe size near the collector. The step is generally made one-half to two-thirds the way down the length of the header pipe. This detail is used to reduce pumping losses on the exhaust stroke, and generally improves horsepower at engine speeds higher than the peak torque RPM. This detail will also make the scavenging wave returned from the collector stronger and narrower. The compression wave following the scavenging wave will also be intensified.
When making stepped-tube primary header pipes, use the two available pipe sizes that have inside diameters closest to the pipe size calculated by the Header Design Program. Use a collector inside diameter that is closest to that specified by the Header Design Program. The following recommendations will help you decide when to use stepped-tube headers.
1. Do not use stepped-tube headers if low RPM torque and part-throttle operation are important. This includes essentially all street and street-strip engines, unless the exhaust port is very restrictive (flow bias 68% or less).
2. Large displacement, high RPM drag race engines will almost always benefit from stepped-tube headers. Launch RPM must be radical and shift points must be significantly higher than the peak horsepower RPM. Performance Factor must be 7 or higher.
3. Drag race engines with conservative shift points and launch RPM, especially automatic transmission equipped cars, may find no net benefit from the use of stepped-tube headers, even though top-end horsepower might be improved.
4. Dragsters of mild to moderate performance level, that race against their dial-in times, will probably have more consistent 60foot times without stepped-tube headers. This is especially true when using 3-speed transmissions.
5. Other race engines operated exclusively at engine speeds higher than the peak torque RPM should consider the use of stepped-tube headers. The decision will depend on the breathing ability of the exhaust port. The top-end horsepower improvement can range from negligible to substantial.
6. Race engines that operate at engine speeds in excess of 7500RPM will frequently require stepped or double-stepped primary pipes. The engine may completely fall out of tune in the lower mid-range with double-stepped headers because of exhaust reversion during the overlap period.
7. The decision to use stepped-tube headers on road race or low-banked short track engines will depend on the RPM required at the end of the straightaways. If the maximum engine RPM is well beyond the peak horsepower RPM, a stepped-tube header designed using a Performance Factor of 4, 5 or 6 may give best times. The ability of the racecar to put midrange torque to the track coming out of a turn will influence the full-throttle operating range of the engine, and therefore the required Performance Factor.
GENERAL TIPS
1. The use of bolt-on open header collector extensions will allow you to fine tune the collector length and diameter. The collector designed by the Header Design Program will generate a smooth scavenging wave of long duration. The entire length of the collector should act as an expansion chamber. When experimenting, evidence of hot-spots on the collector indicates areas of higher pressure.
2. Bolt-on collectors are especially convenient when switching from street hook-ups to open headers on race day. This might allow a smaller diameter collector for street driving, which will improve low-end torque and part-throttle performance.
3. Avoid any details in your headers and exhaust system that will inhibit the smooth flow of exhaust gases. Smooth flow promotes proper header functioning and maximum possible horsepower. Try to keep weld beads and spatter off the inside surfaces of the header pipes. They can cause significant turbulence and energy loss.
4. When making 3-into-1 and 4-into-1 headers, leave a triangular tab of metal on each primary pipe where they join together at the collector. Weld these tabs into a pyramid to eliminate the stagnant area between the pipes. This will improve flow into the collector. The taper angle of this pyramid should be the same as that of the collector reducer. A pinch merging detail can also be use instead of the pyramid. The primary header pipe ends are heated near the central void, then pinched together and welded, eliminating the stagnant area between the pipes,
5. If you suspect that your exhaust valve lift-rate is too radical, a venturi-type collector may provide improved performance over a straight collector body. Testing will reveal if this is the case.
6. Use mufflers and catalytic converters with sufficiently high flow ratings. An H-Pipe, Y-pipe, or X-pipe will greatly reduce the exhaust noise by averaging out the pulsing exhaust waves before they get to the muffler. The resultant smoother exhaust flow down the tailpipes results in less energy loss in the mufflers, and smoother operation of the engine at low speeds.
7. Use the smallest diameter tailpipes that provide sufficient flow capacity. Tailpipe sizes will be smaller than the collector body diameter when three or fewer header pipes feed one collector.
8. Pipes with ceramic coatings or insulation will maintain wave energy better than bare pipes because of the reduction of heat loss. The carbon layer that will form inside your header, exhaust port and combustion chamber is also an excellent insulator.
9. Ceramic-coated headers will help minimize the light-off time of your catalytic converters. Locate catalytic converters as close as possible to the collector outlet, but on the downstream side of the H-Pipe, X-pipe, or Y-pipe.
10. Dozens and dozens of emissions-legal long-tube headers are available, especially for Chevrolet cars and light trucks (See the Resources section). These headers will generally require Y-pipe collectors before the catalytic converter. Make sure the total header pipe and collector length, from the exhaust port to the Y-pipe junction, is correct.
11. The entire exhaust system must be free of leaks to operate correctly.
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شکل نهایی کار کاملا به سلیقه خودت بستگی داره، مهم اینه که این موارد رعایت بشه، به عنوان نمونه میتونی از فرمهای زیر استفاده کنی:
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