If this has been discussed before, just point me to the previous posts. Do shorty headers offer gains worth the price on 4.6L S197? If so, what brand? All I have is CAI, X-pipe, tune, and Flowmasters. Thanks.
4.10 gears will come first anyway, I was just wondering about the shorties. I went to Test 'n' Tune at Atlanta Dragway in Commerce last night. First time on the strip for me. Had a hell of a time. Best ET was 13.906 at 103mph on street tires. I didn't have a helmet, so after I got the 13.906, they told me to park it. They told me in Tech that anyone 13.999 or lower must use a helmet. I heard Silver Dollar in Reynolds, GA is the same. Looks like I need to get a lid...
Shorty headers do give you a gain below the curve but as a net or max hp gain expect very minimal. I like my FRPP shortys but if I had to do all over again it would be Kooks long tubes! The shortys are no easier to install then long tubes so just go long unless in CA.
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2006 Mustang GT Automatic with C&L CAI, FRPP Shorty Headers, FRPP Hot Rod Cams, Delete Plates, TILLMAN 93 Street Tune, Yukon 3:73 Rear Gears, Bassani Axle-Backs. Suspension: Vogtland Springs, BMR - LCA, Adj. Panhard Bar with Support, A-arm Brace, Progress Technology front and rear sway bars, Steeda - frame rail and torque box brace, adjustable upper 3rd link, bump steer kit, front control arm bushing kit, Tokicko D-Specs, & FRPP Strut Brace.
14.99
To prevent radiator overflow from leaking onto the track, NHRA requires an overflow can of at least one pint in volume. This can be as simple as routing a radiator overflow tube into a windshield washer reservoir.
All cars should also be equipped with a proper battery hold-down, even when the battery is in the stock location. Factory stock hold-downs are acceptable in this case. Otherwise, bolts of 3/8-inch diameter must be used to retain the battery. Lug nuts are another area of concern, especially with aftermarket wheels. NHRA recommends all cars be equipped with open-ended lug nuts to allow the inspector to verify the length of thread engagement.
Obviously, all lug nuts and studs must be in place.
NHRA specifies no more than a total of 12 inches of rubber fuel line in the fuel delivery system. This includes the rubber line between the pickup and an external fuel pump and also between the fuel pump and carburetor. In the case of an accident, rubber line is susceptible to damage that could cause a fire.
13.99
NHRA requires a DOT, SNELL or SFI helmet for any car quicker than 14.00. There are a number of different specs so you should check with your local tech inspector.
For cars that run e.t.s between 12.00 and 13.99, all of the above requirements apply along with the addition of a driveshaft loop. A new-for-95 rule exempts cars running 13.00 and slower when equipped with street tires. Since traction is the key to going quick, this places more strain on the driveshaft. To prevent the driveshaft from breaking at the front U-joint area and perhaps coming into the interior of the car, or digging into the track and pole-vaulting the car, NHRA mandates that a steel loop be placed just behind the front U-joint of the driveshaft. A universal driveshaft loop is available from Lakewood that bolts to the floorpan. A rollbar is required in this e.t. bracket only if the car is a convertible. 11.99
By the time a car is capable of running between 11.00 and 11.99 seconds in the quarter-mile, safety requirements are especially important. Up until this point, factory seatbelts are acceptable, but in the 11-second-and-quicker time zone you need a quality safety harness. The minimum requirement is a 3-inch-wide, five-point harness meeting SFI spec 16.1. The 1995 National Hot Rod Association Rulebook outlines the proper way to mount the shoulder harness and belts.
An NHRA-legal rollbar is also required in the category. Recent rule changes have reconfigured what NHRA classifies as a rollbar. The classic four-point bar is no longer acceptable. The new standard is mild-steel tubing of at least .120-inch wall thickness (most chassis companies, like Art Morrison, use .134-inch wall tubing) that includes a forward-running side bar from the main hoop past the driver’s shoulder. This bar is only required on the driver’s side, but most systems include both sides for a six-point rollbar. An SFI-approved scattershield is also necessary in this e.t. category. NHRA requires the scattershield to have an SFI aluminum-foil sticker. According to Red Roberts of McLeod Industries, older bellhousings can be certified by sending the scattershield and block plate to the original manufacturer. The company will inspect the housing and if it passes, it will receive an SFI 6-1 certification. Most SFI certifications are good for five years. Contact your manufacturer if you're not sure.
The clutch and flywheel must also be SFI certified. The main consideration in this area is to avoid using a cast-iron flywheel. According to Roberts, sometime in the mid-’70s most of the new car companies began using nodular iron flywheels that are much safer. Most, if not all, current high-performance aluminum and steel flywheels are safe when used in conjunction with an approved scattershield, but the rules state that the pressure plate and flywheel need an SFI certification number. Roberts says the best plan is to record all your SFI numbers in a logbook. This makes it easier for the tech inspector and it shows the inspector that you understand the importance of the inspection process. This e.t. level also requires steel valve stems in all wheels, along with arm restraints for open-cockpit cars like roadsters.
10.99
Cars running between 10.00 and 10.99 need all the above-mentioned safety equipment, plus driver’s protective clothing, aftermarket axles and an SFI-approved harmonic balancer. The driver needs to have at least a single-layer, SFI-approved jacket such as those sold by companies like Diest, Simpson, RJR and others, as well as long pants and approved driver’s gloves.
The aftermarket axle requirement also extends to installing a C-clip eliminator kit in any rearend that uses a C-clip to retain the rear axle, such as the GM 10- and 12-bolts and the Ford 8.8-inch rearends. While the current NHRA axle rule does not include an SFI spec for axles, experienced axle manufacturers such as Summers Brothers, Mark Williams, Strange and others offer axles intended for this kind of abuse. Harmonic balancers first became a subject of concern on blown cars that placed enormous loads on the balancer driving the supercharger. Now, any car running quicker than 10.99 needs an SFI-approved harmonic balancer to be legal. Companies like Vibratech, TCI, BHJ and others can supply the necessary legal part.
A new NHRA safety rule change for 1995 states that cars running between 10.00 and 10.99 must have a rollcage unless the car has an unaltered firewall, floorpan and body (except for wheeltubs). This means if you have a street car with a stock floorpan and firewall but have tubbed it for bigger tires, all you need is a five-point rollbar until the car runs quicker than 10.00. Of course, a rollcage is perfectly acceptable if you wish to install one.
9.99
Significant improvements must be made to the car in order to step into the 9-second zone. Foremost among these is a rollcage. The cage must be constructed of mild-steel tubing at least 15/8 inch in diameter, with .120-inch wall thickness. It can also be chrome-moly tubing of .083-inch wall thickness with a total of eight attachment points. These eight points refer to the placement of the cage surrounding the driver, including the two rear support bars. NHRA does not require bars that run forward to the front suspension, although many cage designs include them. All cars running 9.99 or quicker must have the cage certified by NHRA and have the NHRA certification sticker attached to the cage.
Attached to the cage is a window net to keep the driver's arms inside the car. The driver must also wear a neck collar and fireproof clothing meeting an SFI spec. Additional requirements include an NHRA competition license, an external electrical shutoff and a flexplate/automatic transmission shield. If your car can run over 150 mph in the quarter, as many of these cars do, then NHRA also requires a parachute to help slow the car down.
If this has been discussed before, just point me to the previous posts. Do shorty headers offer gains worth the price on 4.6L S197? If so, what brand? All I have is CAI, X-pipe, tune, and Flowmasters. Thanks.
4.10 gears will come first anyway, I was just wondering about the shorties. I went to Test 'n' Tune at Atlanta Dragway in Commerce last night. First time on the strip for me. Had a hell of a time. Best ET was 13.906 at 103mph on street tires. I didn't have a helmet, so after I got the 13.906, they told me to park it. They told me in Tech that anyone 13.999 or lower must use a helmet. I heard Silver Dollar in Reynolds, GA is the same. Looks like I need to get a lid...
Exhaust flow is fairly irrelevant in the sense that stock manifolds, shorties and long tubes will all flow plenty of exhaust through them. They are by no means a restriction. But with exhaust you are not trying to “flow” exhaust. There is no exhaust flow in the literal sense. There are exhaust pulses (which are little columns of “flow” if you want to get technical) which if timed correctly can be used to increase momentum (scavenging) of the exhaust gases. A simple way of thinking about it is if an exhaust pulse from one tube reaches the collector right as another tubes exhaust valve opens it will create a kind of vacuum in the collector which will help the just created exhaust pulse move faster. Consequently if the timing of the pulse is off a reverse pressure wave can be created that will bounce back against an exhaust pulse and therefore slow down the exhaust gases.
Log style manifolds (stock) have no “timing” in them and they are effectively very short tubes dumping into a big plenum. And they don’t even have a “collector” to speak of. Stock manifolds, if they create any sort of scavenging effect is purely by accident. Stock manifolds are so simple that they can only be defined by their “flow”. It’s a good thing they have an abundance of it. The stock exhaust manifolds have proven to be a very small restriction to supercharged motors which don’t rely on scavenging like a naturally aspirated motor does. You can make a lot of power with a supercharged motor while still retaining the stock manifolds.
Unequal length shorty headers probably don’t have a flow advantage over a log style stock manifold and if they do have some scavenging effect it is by accident again and minimal. What they do have is a collector. I could go on forever about collector design and why some designs work with some combos better than others but the basics are that a collector should help the individual tubes to merge the gases together in an orderly, smooth and in some cases timed fashion to increase exhaust velocity. The collector is about the only measurable advantage that an unequal length header will have over a stock manifold. I have yet to see concrete dyno results that show unequal length shorty headers offer an hp advantage over the stock manifolds. I have seen a few dyno tests but the testing procedures were sloppy at best and the gains claimed within the standard un-repeatability of chassis dyno’s. Any result from a chassis dyno under 15hp can be easily attributed to inconsistent testing conditions. Simply getting the differential and transmission fluids up to temperature will show as much as a 5hp gain. And that is only one example of many possible variables. The lack of articles about shorty headers and their “gains” is also a big clue that they don’t offer much of a gain if any. If there was a set of shorty headers out there that made even as little as 10hp and 10tq the manufacturer would most certainly be going WAY out of their way to organize a test for one of the magazines to report on. A PROVEN 10hp gain from a set of shorty headers would assure that manufacturer a truckload of sales. And to add insult to injury shorty headers are only about 1.5lb lighter than the OEM manifolds so there isn’t a big weight savings either. In my opinion unequal length shorty headers are a complete waste of money unless you think the money spent is worth how much better they look than the OEM manifolds. I want to want some. They are relatively inexpensive, easy to put on, and may sound a bit better. But the lack of PROVEN hp gains makes them a dumb buy.
An equal length shorty again will “flow” the same amount of exhaust gas as an unequal length shorty and not much more than a stock manifold but by equalizing the tubing lengths there may be a slight advantage in scavenging effect because of exhaust pulse timing. But the primary tubes are way too short to be able to take advantage of exhaust pulse timing. F1 Motors use very short headers, but not as short as a set of “shorty” headers and the F1 motors rev to 18,000+rpm’s! They of course also have a collector which will help a little with exhaust gas velocity. The collector design has everything to do with how well that works though and the only nice equal length shorty with a good collector design I have seen are the JBA ones. Just like the unequal length shorty headers the equal length ones have not been proven to make power over the stock manifolds and for all the same reasons. Technically the equal length shorty header should out perform the unequal length shorty headers but if the unequal length headers are only worth 2hp, which is entirely probable, the equal length ones could be 50% better, which would be a lot and still only be worth 3hp. The equal length shorty headers are a colossal waste of money just like the unequal length ones are. There are literally hundreds of ways to spend your money smarter.
Now long tube equal length “tuned” headers are the cats a$$. Now the primary tubes are long enough to start timing exhaust pulses correctly (or most efficiently) and since they are so long the collector design can be very good because a long smooth merging collector is the most efficient. I’m pretty sure the optimum length for a long tube header on a 4.6L is 32” or there a bouts, that’s what I mean by tuned length. The length dictates the timing of the exhaust pulses and when they get to the collector. If everything is perfect every exhaust pulse helps the one behind it and it will actually start to “suck” the following exhaust pulse (scavenging) behind it. Tuned length and the timing of the exhaust pulses is the key to making a header work. There is a lot of Voodoo in the design of a great header. Take a look at some NASCAR headers sometime, they are incredible.
Other factors in exhaust performance are the heat inside the tubing. The hotter the gases inside the tube the faster they will flow. That’s why ceramic headers or heat wrapped headers are an advantage, they keep the heat in. On some motors, and I don’t know if the 4.6L is included will see a massive exhaust gas pulse timing advantage by taking one primary from each side of the motor and running them over to the other sides collector. This is a product of the firing order of the motor. Windsor motors are like this. This style of header is a “180 Degree” header. You don’t see them much outside of pure race cars because obviously packaging is a nightmare. Strangely enough the X-pipe design came from someone (Dr. Gas) who was trying to mimic the 180 deg style of header. X-pipes help with exhaust timing and balance. It can almost be looked at as a third collector. H-pipes help with balance only.
One last factor to consider in exhaust performance is if you have FI. The scavenging effect or the desire for it isn’t nearly as critical as a NA motor. Why you ask? Because the exhaust pulses are being pushed out with a lot more force because the next piston that is getting its intake charge is being force fed which actually turns the intake stroke into a sort of mini power stroke in the sense it is helping move gases somewhere else in the motor. Now with a FI car the percentage of actual true exhaust flow goes up in comparison to exhaust pulse timing quite a bit because the size of the tubing can now become a restriction and since the exhaust pulses have something behind them pushing scavenging is not nearly as important. A good example of this is that a 325rwhp-ish NA car can pick up 20-25rwhp with some long tube headers and a solid tune. That is a 7-8%hp increase and it will be all the way across the rev range. Putting the same set of headers on a 450rwhp FI car will pick up about 15-18rwhp. That’s only a 2% hp increase. Clearly FI motors are not nearly as dependant on exhaust gas pulse timing, or scavenging as NA motors are. I imagine that if you sat down to design a FI specific full length header you would find that the tubing size, primary tube length and the collector design would need to be a lot different than the NA long tubes to be 100% efficient.
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Under Construction. Better, Stronger, Faster than it was before.
Well bottom line if you talk to someone who has actually put long tubes on a street car they will certainly tell you the car runs alot better, me included...I noticed big gains on a 5.0 and also my 4.6 Cobra...not to mention they sound biatchin'
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"Goose, Hollywood's fine, I want Viper"
1995 Mustang GT Cnv 347(427 stroker being built!) almost done!
1996 Cobra with Kenne Bell 2.1 Supercharger and every other conceivable part you can bolt on it...650hp upgrade in the works
2003 Infiniti M45 V8 340 hp...a methadone treatment for reformed Mustang drivers
Wait Sqidd...You didn't get into the effect of step headers
Well I just finished installing a customer supplied set of shorties on a his 2005 Mustang. He wasn't about the power, but getting rid of his "Ugly rusty manifolds".
I was (A) Not impressed by the quality of internal finish. Will NOT name the brand, but popular. The "collector" looked like that of an old 86 5.0L Mustang stock header.
Now with his off road H and Flowrattler mufflers it sounds weird to me, but he loves it.
Was an easy couple hour install, but I wouldn't bother if it was my car.
Hey J, how'd you come up with 32" for the primaries? You have the formula handy? I know it for a 2.3L Ford at 9200 RPM on methanol. 26"
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2006 Legend Lime GT: Samco, Metco, LPW, Brembo 6 pot brakes with floating rotors, Magnacharger with 8-Rib, LubeLocker, Royal Purple, FR500S front end, APR Performance Carbon Fiber Rear Wing, Roll bar, 10 qt upgraded oil system...Thank you Capaldi Racing for all your help! 2007 Mustang GT/CS : Wife's Car, Magnacharged too. 1966 Mustang GT-K Code Coupe: Restored
Hey J, how'd you come up with 32" for the primaries? You have the formula handy? I know it for a 2.3L Ford at 9200 RPM on methanol. 26"
Oh I can't remember. It was something that I got from another header designer.
On the subject of shorty headers and exhaust pulse timing. I was looking at a set of Formula 1 headers the other day and they had I would guestimate about a 18" primary. And it runs 18,000rpm. What do you suppose a set of 4.6L shorties are tuned for? 25,000rpm's?
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Under Construction. Better, Stronger, Faster than it was before.
What do you suppose a set of 4.6L shorties are tuned for? 25,000rpm's?
They are tuned for Parking lot brag drags, car shows and underhood pics
They may help slightly with NA, but for a little bit more $$$, go long tube and get your money's worth.
The amount of people I see add parts then remove them to make more power amazes me. After 4 years of modding S197s there must be tons of shortys, gear sets and CAI laying around
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2006 Legend Lime GT: Samco, Metco, LPW, Brembo 6 pot brakes with floating rotors, Magnacharger with 8-Rib, LubeLocker, Royal Purple, FR500S front end, APR Performance Carbon Fiber Rear Wing, Roll bar, 10 qt upgraded oil system...Thank you Capaldi Racing for all your help! 2007 Mustang GT/CS : Wife's Car, Magnacharged too. 1966 Mustang GT-K Code Coupe: Restored
Shorty headers on an S197 Mustang 
