IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEADERS



IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEADERS

Postby grumpyvette » June 11th, 2010, 8:22 am

ok you want you car to perform well and you've heard all your adult life, that you need a low restriction exhaust and that a good set of long tube headers out performs shorty's, headers,
you might have researched a bit deeper and found formulas that indicate the ideal length of the collectors and header primary, you might even be the one guy out of 20 that actually took the time and effort to run a flexible tape measure thru each primary and out the collector and found that about 90% of the factory headers use pipes and collectors that are far too short to produce the ideal power range, now what?
AND be aware that there's strait and angle plug, SBC heads and BIG BLOCK HEADS with raised exhaust ports ,and there's round and square exhaust ports, and its smart to check with the manufacturer as to what style heads the headers are designed too fit correctly or you could have major clearance issues.
[color=#FF0000]ITS extremely important that you ask questions and get accurate answers , BEFORE purchasing headers about what style cylinder heads the headers are designed to fit, below is pictured a set of headers obviously designed for factory strait plug heads but bolted to a set of angle plug heads making spark plug access and wiring a clearance and heat , destroying ignition wire nightmare

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http://forum.grumpysperformance.com/viewtopic.php?f=52&t=2712&p=7032&hilit=angle+plug#p7032

http://forum.grumpysperformance.com/viewtopic.php?f=70&t=840&p=9944&hilit=angle+plug#p9944
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Once you get much past the headers, the pipe size has little to do with the power curve unless you're choking the exhaust at high rpm's.
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I have got to agree here,its been my experience on many muscle car engines that a large displacement ,high compression performance engine, thats been specifically camed and geared correctly to maximize the exhaust scavenging will be easier to demonstrate this with than a low compression, mid sized v6 or v8 thats camed to run in the 1500rpm-4000rpm band like most factory transportation type cars are. but the exhaust behind the headers will be less critical than the headers dimensions and collectors design and collector length which can be critical to getting the engine to produce good power over a wide rpm band, but past that you feed both collectors into a correctly size (X) pipe with about 20" on each leg past the (X)and as long as the exhaust system past that point is not restrictive sound levels may change but power tends to be fairly consistent. i usually get that DEER IN THE HEAD LIGHTS STARE when i ask what the exhaust back pressure actually reads with a GAUGE, at the collectors, (X) PIPE and about 12"past the (X) pipe, at peak rpms under load , simply because most guys have never hooked up a guage and watched it as the car ran thru the 1/4 mile lights at top speed
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you might be surprised at what a few tests show you and how much time and money you can avoid wasting.
diam. of the pipes is not as critical as the exhaust BACK PRESSURE the engine sees in the mid and upper rpm ranges, a 2.5" pipe has ABOUT 5 square inches of area a 3" pipe ,about 7 square inches of area so, if you swap from a set of 2.5" exhaust pipes to a 3" dual exhaust , in theory youve reduced the resistance to exhaust flow by 35%-40% which MAY result in some gains if you were previously restricted, adding an (X) pipe adds a further reduction in the restriction to exhaust flow.
knowing a few constants in engine pressure and flow helps, Im always amazed at how few guys bother to measure exhaust temps, exhaust back pressure and fuel/air ratios.

an engine usually requires approximately 2.257 cubic feet per minute per horsepower to maximize intake flow and exhaust flow at about 115 cfm per square inch

so assuming your building a 500 hp engine / 2 (divided by 2 as there's normally two header collectors on a v8) we have 250hp per header collector, (open header collectors) multiply that by 2.257 cfm and you see you need 565 cfm and divide that by 115/square inches and we see we need a 4.9 square inch minimum exhaust collector pipe, per side (open header collectors), or if using mufflers this of course assumes a very low restriction muffler.
its a rule of thumb or rough guide on the expected combined potential max exhaust port flow rates of the exhaust primarys, taken from an observed average of hundreds of recorded dyno results, and not taking into account any flow loss or restriction,and calculating some heat expansion ,its basically worthless except as a way to figuring what size exhaust pipe size thats likely to work, or what size will be restrictive to flow.

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http://www.harborfreight.com/fuel-pump- ... 93547.html
viewtopic.php?f=56&t=1503

viewtopic.php?f=56&t=185

viewtopic.php?f=56&t=1166

viewtopic.php?f=56&t=495


if you look closely youll see the major difference is how easily exhaust flow pulses can move into the adjacent pipe to balance flow, the (H) pipe requires two 90 degree turns while the (X) pipe can easily balance with only part of a pulse expanding as it passes the (X) PIPE) merge point, the ease in balancing pressure, and reducing restriction greatly favors the (X PIPE DESIGN)

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notice the X pipe design has several variations, the type above is more effective than the type below at blending and equalizing the pulse volume from either side but even the more restrictive version below still works well.
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heres a good example showing why an (X) pipe is very efficient at equalizing and blending exhaust pulse flow rates
viewtopic.php?f=56&t=1166

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well most header manufacturers will produce what they feel is a decent compromise between performance and ease of installation, while keeping their cost to manufacture as low as they can, and since a shorter headers easier to install and costs less to produce in materials, and its less likely to have clearance issues far more of the commercial headers are much shorter than the ideal length.almost all header manufacturers need and do find a compromise between building the best possible headers , with the widest potential power band,and the most cost effective design they can build that still functions reasonably well, and fits as many similar applications as possible, and while a longer header tends to produce more low and mid rpm power, the ratio of power gains are reasonably small compared to the added expense of building true custom headers that fit, each possible application, due to clearances, and additional materials, and producing a header that may only fit a single year , with a single engine or type of cylinder heads,or maybe only limited to several years of production, and the cost difference between lets say a 32" and a 36 " header primary design, limiting the market potential, makes producing headers with the ideal measurements cost prohibitive.
the the additional gains are there to be had, but unless your willing to build a custom design that may only fit a few cars, and are looking for every possible gain, it may not be worth the extra effort, if it costs you an additional $200-$300 dollars to build a header that produces an extra 10-15 ft lbs of torque ,(or in some cases noticeably more) most header manufacturers would much rather opt for a less expensive option

there ARE EXCEPTIONS
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and some simple fabrication work to graft on collectors like these
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to common headers like these
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usually results in gains in performance, at a reasonable cost to the few guys willing to take that extra effort



well the more advanced guys, and racers have found that that making longer headers out of short factory designs is far less work intensive than building headers from scratch, and its fairly quick process to correct, with longer collectors or primary pipe extensions like pictured below,
but that usually requires some minimal cutting and welding to produce a decent , semi custom header, so if you don,t have the skill or tools many guys avoid doing it!

yes its usually well worth the cost and time and effort, most guys who have never had a car with headers of the optomum length have never seen how effective true tuned headers can be or heard and felt the difference they make over the crappy store versions with the much shorter tubes
you can usually use a band saw or cross cut saw to cut of the usually pathetically short factory collectors and weld on an extension giving you noticeably more low and mid rpm torque, that the factory supplied version.
collectors, like those pictured below that transition from 4 primary too two secondary to one collector usually produce better mid and low rpm torque without sacrificing much if any peak hp over the 4 into one collectors, and the smooth merge collectors that are usually far less restrictive can sometimes provide very noticeable improvements in the upper rpm range.
naturally if you match any header to a restrictive exhaust, or use mufflers that restrict flow your effectively killing off a great deal of its potential, just as a restrictive intake system will restrict the headers ability to scavenge the cylinders or if your using a cam that's not designed to run in the same rpm band as the headers and intake are designed to flow efficiently in, so it pays to take the effort to measure back pressure and include an (X) pipe and low restriction mufflers if you do run an exhaust system, and match all the engine components to a single intended power band, and, Id point out that having cut outs to further reduce restriction for on track use can at times help.


use these calculators and measure your current headers and youll find that about 90% of the time they are far to short to provide the ideal power curve
keep in mind the idea behind running headers is to significantly increase cylinder scavenging increasing the width of your power band by increasing the rpm range the cylinders fill efficiently



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if your headers primary and collectors are too short, your engine may never reach the rpm range where its providing much help to your power curve

http://www.pontiacracing.net/js_header_length1.htm

http://www.wallaceracing.com/header_length.php

http://www.carcraft.com/techarticles/11 ... ndex2.html

http://victorylibrary.com/mopar/header-tech-c.htm

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http://www.summitracing.com/parts/FLO-C134218234/

http://www.summitracing.com/parts/HED-14044/
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IF YOU WELD STAINLESS EXHAUST PIPE without a back flush you can get weld crystallizing or SUGARING , an ARGON back flush and taping both ends to exclude oxygen helps reduce this significantly as will tig paste


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http://www.solarflux.com/Pages/Productinfo.html
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a well thought thru design on an (X) pipe and cut outs
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viewtopic.php?f=56&t=495

viewtopic.php?f=56&t=1166

viewtopic.php?f=56&t=1303&p=16831#p16831
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEA

Postby grumpyvette » September 30th, 2013, 10:35 am

S.D.C. wrote: grumpy, I like the way side exhaust headers look on my corvette, but my mechanic swears they will not allow my engine to put out nearly as much power as a good under the car exhaust system would,my old side exhaust is getting old and rusted and the inserts are falling apart, I obviously will need to install a new exhaust system and the new side exhaust will be about $1300 vs about $800 for an under the corvette exhaust after pricing both out any ideas?




well the truth here depends on how your going to measure the horsepower and what components are used, both the under the car exhaust and the side exhaust can produce very good power, but personally i prefer the side exhaust, but I will point out that there's factors you must consider, a good side exhaust is generally lighter in weight and more efficient in my experience but its also usually strangled by the use of restrictive baffle inserts, its those inserts and the potential for you to burn your leg exiting the car on a hot exhaust that makes the side pipes less appealing, to many people..
inserts like these significantly reduce noise but Ive seen dyno tests where the insert removal was worth 90 plus hp, and it would more than likely be more if the car was tuned to take full advantage of the headers with the insert removed.
Ive seen custom inserts that were designed from preforated metal baffles that both reduced noise and significantly increased the power the side pipes produced, but I think theres such a limited market potential that not much research is going on,nor are there many options in over the counter side pipe insert baffles available.


inserts like these are what most side pipes come with and while they lower noise they hurt power over about 3500rpm in most applications
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Ive always like the look of corvettes with well designed a side exhaust
but they get a bad reputation from guys who have girl friends burn the back of their legs exiting the car on hot side pipes, or guys that insist on running extremely restrictive inserts to reduce the noise who then bitch about the resulting loss of power

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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEA

Postby 87vette81big » September 30th, 2013, 12:32 pm

Grumpy, I have a set of Flowmaster Weld on Merge collector extensions.
The 4 into 2 into 1. I think 1-3/4 or 1-7/8 and collector exhaust outlet is 3" .
They were given to me with a set of homemade Pontiac Ram Air 4 round port GTO headers.
Slip on extensions with weld tabs.
Forgot I had them.
New never used.
I have Hooker Super Comp Headers for the 87 Corvette.
Plan on using with my 410sbc for now till I can afford Stainless custom made headers or Take time to fabricate big tubes with a friends help.
Thinking now of using the Flowmaster 4-2-1's with Hooker Super Comps.
They are real short primary tubes as you recall.
Old school but bought at decent price & lightly used.

What is the correct orientation of the 4-2-1 collectors ?
Does Verticle position give bottom end torque ?
Does hornizontal give midrange & top end power ?

I can make it slip fit or weld fully myself.

The Stahl headers were best ever made.
Tried to have them custom make a set a few years back.
Economy forced them to shut down.
The Stahl 180 degree headers shown are a work of art & Performed like none other.
Legendary. With Pontiac Trans Am owners too.

Thanks Grumpy.

Brian R.
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Re: IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEA

Postby grumpyvette » September 30th, 2013, 1:51 pm

some simple fabrication work to graft on collectors like these, is required Ive generally installed them, indexed as the picture shows due to slightly better cross member and frame clearance considerations, I doubt it makes a great deal of difference because your not going to get a true equally spaced exhaust pulse config on both headers no mater how they get indexed, on most standard commercial headers, but what you do get is usually a noticeably wider rpm band torque curve
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if you do the measuring, of the commercial headers and then do the math calculations and compare both, youll frequently find commercial header primary tubes are 4"-10" shorter than the calculations indicate would be ideal
IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEA

Postby 87vette81big » September 30th, 2013, 2:13 pm

grumpyvette wrote: some simple fabrication work to graft on collectors like these, is required Ive generally installed them, indexed as the picture shows due to slightly better cross member and frame clearance considerations, I doubt it makes a great deal of difference because your not going to get a true equally spaced exhaust pulse config on both headers no mater how they get indexed, on most standard commercial headers, but what you do get is usually a noticeably wider rpm band torque curve
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if you do the measuring, of the commercial headers and then do the math calculations and compare both, youll frequently find commercial header primary tubes are 4"-10" shorter than the calculations indicate would be ideal


Thanks Grumpy.
I will measure.
When I recieved my lightly used C4 Corvette Hooker Super Comp's Headers I couldn't believe how short the Primary Tubes & collectors are.
The Hooker Super Comps Round port RAM AIR 4 Headers are way longer.
Long collector. The TA always had a very wide powerband.
2,000-7000+. No matter how radical the cam profile was used.
Credit to the nice header design & true dual 3 inch exhaust I installed.
The Vette I may use an X pipe layout.
Flowmaster 4-2-1 about 12-14 inches long I recall.

Thanks again Grumpy.
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Re: IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEA

Postby 87vette81big » October 1st, 2013, 7:05 pm

So I tried out The Wallace Racing Header calculators Grumpy.
In theory I need about 30"inch long primary tube length.
1.92" inch ID primary tube diameter.
3.3" Collector diameter.

Or 30" primary length. 2" Inch primary tubes.
And a 3-1/2" collector.
Assuming 100% Volumetric efficiency. 410 cubic inches.
7000 Rpm Redline.
Right on target what I wanted original for my 1987 C4 Corvette.
I figured 28"-30" collector original.
Same specs as my 1970-1/2 TA round port Ram Air 4 headers are.
Just no one makes them.
Only Kook & Lemon Headers will make. Fork over $2000-3000.

Every C4 Corvette owner is getting screwed with aftermarket headers supplied current.

Will stick a tape measure down my C4 Hooker Super Comp Headers.
Get a Mean measurement.
Recalculate. 1St estimate......headers 10-12" inches too short for my 410sbc.

Also the Pontuac Ram Air 4
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Re: IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEA

Postby 87vette81big » October 1st, 2013, 7:07 pm

Also the Hooker Super Comp Headers Pontiac Ram Air 4 a perfect match on the 462ci - 455poncho as is.

Go figure. C4 Corvette guys get screwed.......crap.
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Re: IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEA

Postby grumpyvette » October 1st, 2013, 8:17 pm

I know from experience that adding those longer header extensions after very careful measuring and cutting and welding changes the sound , feel and effective torque curve , yes at times they will need to be angled or slightly shorter, or have the collector section angled or curved due to clearance issues
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Ive generally tried to get a 36"-39" primary tube length as I find thats about the best result for a street/strip SBC
look take a 383, install a crower 00471 roller have about 10.5:1 compression

http://www.wallaceracing.com/header_length.php

if you take a 383 with about 10.5:1 cpr and a crower 00471 cam and 1 3/4" headers (remember to add 15 degrees to the .050 lift duration to get valve seat timing)
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http://www.crower.com/index.php/chevy-2 ... -7041.html

http://www.crower.com/index.php/searchr ... 71&x=0&y=0


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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEA

Postby 87vette81big » October 1st, 2013, 10:34 pm

I removed the Flowmaster 4-2-1 exhaust collectors tonight Grumpy from the homemade GTO headers.
Cut tubing off with my Sawzall few inches ahead.
Few tack welds to grind off in the morning.
23 inches overall length.
The C4 Hooker primary tubes measure 24-32"
All over the board.
Advertised as 26" primary length.

Some time to plan & think things over.
410 has a 3.800" stroke.
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Re: IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEA

Postby 87vette81big » October 2nd, 2013, 5:36 am

Lets Review all available current headers for a C4 Corvette with a 23 degree cylinder head style exhast flange.
We want to build a Car to compete against a Race Machine on Yellow Bullet Drag Racing Forum.
Not a show & shine Puts around making noise Calling its fast when a bone stock 2012 Ford Cobra Supercharged Mustang will eat 99.9% of C4 Corvettes owners For lunch. At the 60 foot starting lne the Super Mustangs already long gone.
Good driver with Drag Radial Tires. He clicked off a Low 10-second Run in 1/4 mile.

Lets Review more.
550-600 HP. 410 CI. Custom ground Crower grind. Inverse Radius Profile.
Race grind. Not a street grind.
Safe lowball redline 7k.
Crower Rods. Other good stuff inside.
Engine was built by my late bud Bill to beat a 10-second Track Camaro that street raced at night.
Never made it into his 85 Corvette.

Built 700R4 to take 600Hp by me.
In my 87 Vette.

IRS Dana 36 going bye bye.
Wil never hold up.
Had a Dana 44.
Realized never hold either. Rebuilt it & Sold it.

Bought a Competition Engineering Pro Magnum 4-Link Kit.
Full 4130-4140 Chrome Moly. One of the very best made.
1957-58 Pobtiac Olds 9.3 Rear will be used.
Last edited by 87vette81big on October 2nd, 2013, 6:08 am, edited 2 times in total.
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Re: IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEA

Postby 87vette81big » October 2nd, 2013, 6:01 am

At least 2 3Rd members built. One with 3.64 gears Posi Street.
Track 4.10-4.88 gears Race Spool locked Axles.
28" tall tire. Drag Radials slicks. Nothing in driveline a weak link .

Current fancy C4 headers available.

Stainless Works. 1-5/8 inch primary tubes. Too small....
$1600 Waste of $$$.

Melrose headers. Stainless too. 1-5/8" primary tubes. Too small. again....
$1600 Waste of $$$$ again.

ARH or American Race Headers.
Stepped headers.
1-7/8" to 1-3/4". No primary length given. $1600 waste of $$$ again.

Leaves China copycats. We won't go there. Screw them .

Ok, Headman & Hooker Super Comps.
Old school.
Hookers known to fit good.
Very compromised design.

Want 2" primary. Can settle with 1-7/8".
3-1/2 Collector.
28"-30 " long primary tubes.
Nothing out there fits the Bill.

Only Hooker
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Re: IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEA

Postby 87vette81big » October 2nd, 2013, 6:03 am

Only Hooker Super Comps for a round port Trans Am.
Won't fit on a SBC.

SO WHAT'S A GUY TO DO GRUMPY ??
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Re: IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEA

Postby 87vette81big » October 2nd, 2013, 7:17 am

Hedman C4 Headers 1-5/8 primary tubes. No good also.

Hooker Super Comp 2151 has 1-3/4 inch primary tubes. Advertised 26" length.
3 inch collector.
Costed me used $125. Fleabay.
Dont feel so bad.....didn't waste $1600 on shiny stainless C4 headers that suck in design to begin with.
Its no small wonder to me Grumpy why C4 Corvettes have a bad rap for being slow........
Can't get high Rpm exhaust flow out with 400+ cubic inches.
They keep dinking with Factory IRS Rear too.
Never hookup & Pull a wheelstand with that......

BR
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Re: IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEA

Postby 87vette81big » October 2nd, 2013, 6:29 pm

I took some photos of the 1987 C4 Hooker Super Comp Headers & Flowmaster 4-2-1 Collector Extensions I have.
Are they worthwhile using 4-2-1's Grumpy ?
Or just use the Hooker Headers as is ?

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Re: IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEA

Postby grumpyvette » October 2nd, 2013, 7:31 pm

I think the answer depends on both your fabrication/welding measuring and cutting skills and your desire to try too maximize the engines power potential, I,m my experience theres no question, that if its done correctly youll make a bit more power, but it will also take some effort and might or might not be worth your time for the power youll gain.
now that might be anywhere from 15 hp to 50 more hp, dependent on the combo those headers are matched too.
and I don,t see the process of carefully fitting,the headers on the car, measuring and cutting the headers and cutting , trial fitting and welding the extended collectors several times (from experience) taking less than 4-6 hours, at 15hp that may be a waste of time in most guys way of looking at the time spent vs value gained,but the gains in lower rpm torque usually make taking the effort worth while, at 50hp I think most guys will see it as a really good move, but you won,t know what youll get until your done testing,and a good deal depends on the level of flow restriction past the collectors and ideally youll use an (X) pipe to blend the exhaust pulses as that tends to add to the torque curve by increasing exhaust scavenging efficiency, and yes I fully admit in some cases clearances under the car make the modification and resulting under the car road clearance a total P.I.T.A., making you wish you were never involved so measure very carefully and think about your skill level with a welder and ability to make precise cuts well before you start cutting up your headers to add longer 4-2-1 collectors, and don,t ignore the road to collector clearance issues!, its a whole lot easier to do the mods on a car that has decent ground clearance like a 67 GTO than a 1985 corvette!

IF you shop carefully youll find you have dozens of options for a STAINLESS 3" exhaust for your muscle car, don,t just jump on the first exhaust you find, actually compare what you get and cost and try to look over instructions and pictures
remember stainless costs more up front but easily last 3-4 times as long.
and your never going to get a true high performance car to perform to its full potential with out a decent exhaust
If your swapping to a larger 3" exhaust with an (X) pipe, it has or will more than likely reduced your engines exhaust restriction this tends to lean out the fuel/air ratio, which can reduce torque ESPECIALLY if you still have shorty stock exhaust manifolds that don,t always scavenge the cylinders correctly at all rpm levels, you can generally get back the torque and add upper and mid rpm power with correctly designed long tube headers, but most engines with factory injectors and tuning run rather lean for passing emission testing. and most original cams are more concerned with mileage and drive-ability than torque and peak power.
every change you make effects the way the car runs, if you reduce the exhaust restriction it potentially allows the car to make noticeably more hp, but REQUIRES there engines are re-tuned to match the new conditions and having a longer duration cam and larger injectors , or increased carburetor jet sizes and long tube headers certainly helps take advantage of the lower exhaust flow restriction.


http://www.highperformancepontiac.com/f ... ntiac_gto/

http://www.magnaflow.com/07techtips/pdfs/15898.pdf
http://static.summitracing.com/global/i ... 15898_.pdf
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http://www.summitracing.com/parts/pye-s ... /model/gto
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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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Re: IM ALWAYS AMAZED AT GUYS THAT JUST SLAP ON factory HEA

Postby 87vette81big » October 2nd, 2013, 8:06 pm

I never lowered my C4 Like most have Grumpy.
The C4 convertible sits higher than the coupes.
The giant X brace has saved my fiberglass floor pans several times from road debris & steep driveways with a hidden potholes.
Still in the planning stages.
Most of parts bought for the 410 .
Common sense tells me to complete the solid axle conversion next.
So driveline is up to par for intended use.
I am not of afraid of fabrication or welding. As long as I planned ahead.
At least I won't lose HP & Torque.
I will use the 4-2-1 collector extensions.
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