stepped headers

[Celica RA45]

has any 1 seen any web pages that talk about 4 into 1 stepped headers at all thinking of going to the dark side

[AJPS]

People need more info glen!

[70XIN]

I wondered if anyone would ever bring this up :)

http://img192.imageshack.us/img192/694/4agheader.jpg

*sorry for the big picture guys, but you wouldn't really notice the 'step' without it this big*

JSPfab in the US has been making all kinds of 4A/F20C/etc headers for a while, has remade the genuine TRD headers etc etc. His new lot of headers are stepped, and have made more power than any of his previous headers. I really haven't read much on the web that's very helpful, it seems most people keep their info close to their chests *waves fist around*.

http://www.jspfab.com/catalog/i63.html

[Celica RA45]

well i have been trying 4 into 1on the dyno with slip joints and have made more power and torque than the trd pipes but the hp justs flattens off at 7600 and its still making the same power at 9000

[Frak]

Do a search I have some dyno runs done on an ST using std headers then stepped headers, they were 4-2-1's but were stepped primary pipes.

[lolwat]

those headers are the SEX!

[khoala]

jesus those are a work of art! but i heard they're only worth it if you're running huge cams as you'd lose torque in the low/midrange with stock or mild cams?

[xero]

I wondered if anyone would ever bring this up :)



*sorry for the big picture guys, but you wouldn't really notice the 'step' without it this big*

JSPfab in the US has been making all kinds of 4A/F20C/etc headers for a while, has remade the genuine TRD headers etc etc. His new lot of headers are stepped, and have made more power than any of his previous headers. I really haven't read much on the web that's very helpful, it seems most people keep their info close to their chests *waves fist around*.

http://www.jspfab.com/catalog/i63.html


when i was looking at them john was saying that for the first section they are 1.5" then step up to 1.75" with a 2" collector and then a 2.25" pipe off that.
they are basically the same style and shape they were running on the formula atlantic cars.

the stepped headers im sure would provide that extra little of flow up top, but the hardest thing i reckon would working out where to enlarge to the next step and how big to make it.
i agree toxin a lot of people hoard that sort of information, and again looking at websites reading info you can sort of only get bits and peices which you then have to put into some sort of order. i can understand that if your trying to get the edge over the guy next to you, but if your no longer racing or involved people should really share what they have learned.

[Gunner]

when i was looking at them john was saying that for the first section they are 1.5" then step up to 1.75" with a 2" collector and then a 2.25" pipe off that.
they are basically the same style and shape they were running on the formula atlantic cars.

the stepped headers im sure would provide that extra little of flow up top, but the hardest thing i reckon would working out where to enlarge to the next step and how big to make it.
i agree toxin a lot of people hoard that sort of information, and again looking at websites reading info you can sort of only get bits and peices which you then have to put into some sort of order. i can understand that if your trying to get the edge over the guy next to you, but if your no longer racing or involved people should really share what they have learned.

From what I have been told by the "older" generation, they use a mix or pyro's and pressure measurements. One particular oldie, explained how its all about gas expansion, and by measuring the exhaust gas pressure, and temps, you can calculate where the gas slows down and causes the restriction, in turn by flaring or expanding the pipe, you can allow gas velocity to remain constant, as it cools on its way through the exhaust system. How true, I don't know, as xero said old school racers don't like giving up much info.

[xero]

yeah, when i had my exhaust done recently i was discussing this with the owner of the shop. he was saying that as the gasses cool down and increase in desity you step up the next 0.25" IE 2.25 at the collector, stepped up to 2.5" after the cat, until the rear muffler. he was saying this is good for constant flow but ends up with a really boomy and blaring exhaust (think FWD lancer/pulsar/corolla/civic with a cannon muffler) and is not fun on the street. race car no worries as its usually just a straight through pipe, street car usually leaves you deaf after driving it.

the calculations idea is a good one, except im a bit slow in the maths dept. so it would have to worked out the hard way. i forgot to mention the 1.5" section was for the first 10-12" (250-300mm) and 1.75" section length was around the 12-16" length (300-400mm) then into the collector.
rough sizing didnt have them physcally much bigger than the TRD copies, but with a bit more work into them.

just going off the top of my head i would say running a 1.5" primary for 400mm them stepped up to 1.75" for the remainder 500-600mm with a 2.5" collector should make bulk power at the top, whilst still providing low end pressure and torque. i reckon by the time the exhaust gases are halfway down they would be losing their temp and would need to expand some where, also the actual length of the primaries would play a part as well. long primaries would reduce heat quite quickly as they would have much much greater surface area than if you ran shorter ones, and as such the longer the headers the faster the gases would be moving by the time they hit the exhaust system itself so would necessitate a step up into the main exhaust pipe.

well at least that make sense in my head..

[86coupe]

Er, gases contract when they cool. Maybe the fundamentals of the universe have changed since the exhaust shop guy went to school :P

You're 100% right about 2.5" being no fun on the street.

[Gunner]

no, gasses become more dense as they cool, dense gas is heavier, harder to shift, hence the restriction.

[slide86]

Er, gases contract when they cool. Maybe the fundamentals of the universe have changed since the exhaust shop guy went to school :P


no, gasses become more dense as they cool, dense gas is heavier, harder to shift, hence the restriction.

you are both right

as a gas cools it becomes more dense, convection (?)

as a gas cools it contracts ie gas in a ballon contracts, has less pressure, hense the ballon contracts in size

[blinded]

^^ Going off that then, is the reason for the step up to compensate for the increased density of exhaust gases, thus requiring a larger diameter pipe to effectively flow the same amount of dense gas compared to a smaller diameter pipe with hot/less dense gases?

Not sure if that makes sense as I am tired as lol! Either way, it is quite interesting stuff, something I had never really considered before.

[Gunner]

that is correct dude, as far as i know it is anyway.

[--Redwork--]

If your ever going to go to the extreme 10 10ths of chasing every last missing horse just contact burns stainless... http://www.burnsstainless.com/
Tell them EXACTLY what you engine specs are... are you will need to know EVERYTHING.. not just cam size and compression.. ect..
They will want to know what cfm your head flows, duration and lift of your cams.. also how you have them dialed in and lob centers. every consevable parameter of your engine they will ask you.
And then.. they will work it all out and tell you EXACTLY how to build you headers. pipe sizes, distance from flang to each pipe size increase. the size of the increase. what size you collector needs to tapper down to befor it tappers back out to the size of exhaust they will tell you to run.. even the degree of tapper required...
And i have seen dyno runs from a burns designed header vs the best aftermarket headers available. NO contest Burns is miles ahead of the next best..
One example is saw was on a built FWD sr20... burns vs ???... the burns only made 10hp more peak.. but through the mid range made over 35hp more.. thats a massive improvment on and engine only make 220hp peak power.

[xero]

Er, gases contract when they cool. Maybe the fundamentals of the universe have changed since the exhaust shop guy went to school :P

You're 100% right about 2.5" being no fun on the street.

yeah i re-read it steve, it was me who had i backwards...
blame it on caffiene wearing off, work shitting me, almost lunch time, planets werent aligned, second coming of jesus etc etc..

[KENut]

^^ Going off that then, is the reason for the step up to compensate for the increased density of exhaust gases, thus requiring a larger diameter pipe to effectively flow the same amount of dense gas compared to a smaller diameter pipe with hot/less dense gases?

Not sure if that makes sense as I am tired as lol! Either way, it is quite interesting stuff, something I had never really considered before.

I would have expected that in the primarys the gas is still expanding, because for a 'proper' air/fuel burn excess fuel is supplied, and unburnt fuel exits into the exhaust. Kinda like a two stroke expansion pipe perhaps.
And then a reduction in pipe size at ~ diff, due to gas cooling and increasing density, to keep the gas speed up

Not saying I'm right or anything

[Sam-Q]

I thought the step was for an intermediate harmonic reversion wave?

[af300e]

I thought the step was for an intermediate harmonic reversion wave?

That's what I thought. Similar to a 2 stroke pipe (but different phasing).

[Gunner]

You guys are probably right, but I don't know enough to be able to comment.

WHats your theory sam?

[Celica RA45]

thanks guys have got all of my info now will be making a set of 1and 3/4 inch then step up to 1and 7/8 and see how that goes
these are for a 3sge motor red line is 9600 rpm

[Sam-Q]

that size for your modded beams? sounds very small in diameters for your secondaries

[Celica RA45]

these are 4 into 1 sam ,so doesnt have to be as big need air speed and beams head is big inlet ports

[Sam-Q]

a 1 7/8" final pipe size!? also what does the inlet have to do with it

[Celica RA45]

stepped header is 1st is 1/34 then about 8 inches further away is steps up to 17/8 and then merges together tapers down to 21/4 and then tapers up to 3inch

[xero]

that actually sounds like it should flow very nicely, keep us updated with the results if possible.

[MAGIC MAN]

the black art of stepped headers, adam i would have started with 1 5/8" on yours to let the gas expand out of the cylinder head then gone upto 1 3/4 to the collector. Gone down to 2 1/4 than upto 2 1/2 to the cat then 3 from there to the back. But thats me lol.

My old 20v ran 1 3/4 out of head upto 1 7/8" to the collector. 4 into 1 down to 2 1/2 then upto 3" to the back of the car.

I have done 4-2-1's stepped headers on a few hondas to, a std aus spec k20a type r engine with standard header's, high flow cat and 2 3/4 exhaust,bigger throttle body and cold air produced 141kw at the wheels, the same car with stepped 4-2-1 headers produced !73kw, just from the headers. it also needed bigger injectors to as it was leaning out. but even bofore the injectors were fitted it made 160ish.

After the extractors, yeah there are gains to be made by stepping the exhaust but i preffered to run it the full size all the way, soley due to the temp issue, with how close most exhausts i made being to the floor of the car(s) i didn't like keeping the temp in the axhaust.

I need to find the pics but i have awsome pics of my old hatch on the dyno and the exhaust glowing all the way upto the diff. Fuck i punished that car on the dyno, but it did prove and dismiss many theory's

[xero]

after getting it back from the tuners recently beau with the new headers and exhaust, i couldnt be happier with it mate.
i didnt pick up any extra power from previous but torque, response and pick up all increased by a huge amount. i also got another 1500rpm in the top end too, this is still with the stock smallport cams, so hopefully when the cams go in i should pick up a heap more power.

when i get my licence back beau, ill try and make a trip down to show what i got otherwise you can view the headers in various locations on the internet...

[70XIN]

what size step/s were the K20A headers?

a 32 fwkw gain from just headers?

[fantapants]

well headers and bigger injectors and new tune im guessing?

[Celica RA45]

i just got me my new stepped headers 1 3/4 step up to 1 7/8 and taper down to merge 2 1/4 then taper cone up to 3 inch also new head with 575 thou lift cams or over 14mm of lift still using 1 tooth vvti and using my new curved ram tubes .will find out next wednesday how it goes

[Rice86]

will that be an efficient test to see out right power gain?...cause you have changed other bits of the car and not only the headers...
points back to the K20a test done, it got to 160 with just headers being changed or did it get minor tunes etc etc

just asking, not saying it wont be an efficent test lol

[Celica RA45]

have 3 sets of headers to try .the TRD 1s with shorter ram tubes .1 set of pipes for winton and the stepped set up with
curved ram tubes

.so will see what is better

also had to put on new head as cams wont turn on the other head ,we will see how it goes

[Rice86]

now that will be an interesting insight
good luck next wednesday !! =]

[assassin10000]

Yeah, pics/video please. Be cool to see what (if any :shocked:) gains from the stepped headers. Good luck!

Andrew

[Celica RA45]

also forgot to add that both heads flow with in 1cfm of each other ,same valves as well and both ported by same guy

[MAGIC MAN]

honda headers, were 1 7/8" to 2" down to 2 1'2 at collector then back upto 2 3/4" for catback. Yes the car did receive some tuning as it simply ran out of fuel and ran to lean. However instead of making the 140kw at 8400rpm it made it just above 6500rpm so there was a considerable gain there.

Adam the 1500rpm higher power band is due to the increased exhaust size mostly, On my old 20v's first dyno session with a 2 1/4" exhaust i didn't even make 100kw at the wheels, i think it was 96 from memory but it only made power to 7000rpm. That was with 1 5/8" 4 into 1 extractors primary length was 28" all equal length too. Second time round same headers, 2 1/2" exhaust this time the car now produced 105kw and power stopped at 7800rpm. Third time round, i ported the head some more, changed velocity stacks (same length just a bigger opening and better bellmouth) bigger headers and 3" street exhaust, the lil 20v pushed i think it was 121kw at the treads and power stopped at 8400rpm. Then i started breaking T series axles and centres, haha. Then i was curious how much power could i get out of the engine, the head came back off got some meat taken off it, a 0.8 head gasket went in. static comp was 11.8:1. Alternater underdrive pulley, electric water pump, and a race side pipe was made. And then the car came to life, the short exhaust made the car run leaner so more fuel was added, the electric water pump free'd up a lil bit more power. Now i never dyno'd this setup so i can't quote figures, and tuning was done by wide band and seat of the pants. But it was a noticable gain the car went from just spinning the tyres as i shifted into 3rd gear, to actually wheel spinning through third gear, so there was a definate torque increase. And the engine also was a lot happier to rev.

I know this has gone a little off topic but basically changing the exhaust size changes where the car makes it's power, ie, smaller exhaust dia power at lower rpm, larger exhaust dia power at higher rpm. And with an engine essentually being a big pump, every pump has a max efficiency rpm, so you need to match everything around that. even though i have gone down the honda path for my car i am still curious about the little 4AGE and i think well on paper and the good old desk top dyno program, i can't see why i shouldn't be able to make over 150kw at the wheels with a 16v and reliably too, one day i will try this

[Dongaz]

Considering the standard exhaust port sizes on the 4age 16v are around 34mm, why is it ok to step up straight away to 1.5" (38.1mm)? Would you not want to say use 1 1/4" for the initial 4" from the flange then step up to 1.5" primaries?
Supposedly having the first 4 inches straight helps, can't remember where I read that though.

[MAGIC MAN]

ok well the OD of 1 1/4" is roughly 32mm which is already smaller than the port but the ID is what your after so the ID of 1 1/2" tube is roughly 35mm which is closer and yes it is much better to come out of the head with straight pipe but not straight out of the head, i always tried to keep it at a similar angle to the port.

[xero]

thanks beau!
that actually confirmed a few things i was wondering about, so once cams are in (and i have my licence back) ill take you for a spin. i would be keen to get your input on it as well..

[Dongaz]

ok well the OD of 1 1/4" is roughly 32mm which is already smaller than the port but the ID is what your after so the ID of 1 1/2" tube is roughly 35mm which is closer and yes it is much better to come out of the head with straight pipe but not straight out of the head, i always tried to keep it at a similar angle to the port.

I forgot that if you are using buttweld fittings or what most people call steampipe you will have different ID's for the pipe.

1 1/4" tube (32NB) is 42.14mm, if you get SCH10 the wall thickness is 2.77mm so the ID will end up at 36.62mm and if you get SCH40 with a wall thickness of 3.56mm ID will be 35.04mm.

1 1/2" tube (40NB) is 48.26mm. SCH10 2.77mm wall = 42.72mm ID (This works out to be 1 5/8")
SCH40 3.68mm wall = 40.90mm ID.

Hope this helps anyone getting the tube and elbows. Atm I haven't figured out where they get the imperial sizing but it is based off the NB (Nominal Bore).

[70XIN]

He won't be using buttweld/steampipe for headers. He'll be using 1.2/1.6/2mm wall tube.

[MAGIC MAN]

i'm about to buy buy some burns stainless pipe and stuff for my turbo headers, ooh yeah

[Gunner]

buy me some.

[Frak]

i'm about to buy buy some burns stainless pipe and stuff for my turbo headers, ooh yeah

I've used their stuff before(collectors etc), expensive but very nice.

[Celica RA45]

the stepped headers worked well with power from 4000 all the way to 8600 rpm ,still need to sort the cams out ,it seems to run out of puff with these 14mm lift

[ke_70]

when do you throw it on a dyno if you havent already.

[Celica RA45]

i ran it up last wednesday week with new head on old 2 year bottom end

[xero]

the stepped headers worked well with power from 4000 all the way to 8600 rpm ,still need to sort the cams out ,it seems to run out of puff with these 14mm lift

is it right at the top glenn or and by puff is it plateau-ing in power or dropping a bit..?
maybe some slightly larger duration cams or and advance on them might help?

[Celica RA45]

these were a new set of cams ,i might go back to the super tourers that i have they keep making power till 9 and are only 535 thou lift another thing i put my trd set back on and power stopped at the same time.
but know i need longer ram tubes as my 30mm are 2 short and the 90mm are 2 short so im going up 25mm longer to see

[xero]

wow, thats really interesting.
so even though you put your old pipes back on it still stopped making power at the same time... i would have though with that much lift it would plenty in it, right up to 10000+ rpm.

at least you know the new headers make a difference under the curve!

[MAGIC MAN]

i'd say the limiting factor here is the intake, the actual throttle size maybe to small therefore limiting the amount of air the engine can take in or the head may not flow enough, and the bigger cams simply show this at a lower rpm,

[assassin10000]

Cam duration could also play a role. IIRC glenn limited himself to keep the VVT-i still working and instead started going to higher lift. To have power higher in the RPM band he may have to sacrifice even more VVT-i usability. It could be he's just reached that point... but it's kinda hard to tell from here.

Andrew

[Celica RA45]

so you guys think 50mm quad throttles might be 2 small and maybe the injectors are 2 small as well im using 440cc inboard and 1000cc out board ,im only joking ,these were new cams ,so will have to try something else '
throwing a std motor on with 48mm and 2stage this coming weekend .will see what this makes

[xero]

larger throttles might work?
as beau and andrew have said, it could be a number of things like you finally find the limits of VVTI?

a bit side ways topic here, but aaaaaaaages ago (at least 4 years) i was at a toymods wakefield day and there was a orange KE15 (or 25, or 35) coupe and was running a 3SGE (NFI if it was beams or not, didnt look like it..) it was doing testing. apart from other shit it was testing it was doing comparo's with ram tub lengths. it wasnt fucken rocket science, the basically had clamped a 50mm odd diameter tube (like you might find on a pool or something) to the throttles and then just taped a cut off funnel to each end.
i remember they were fucken long, like more than 300mm long and eventually were cut down to about 200mm long and were gonna poke the bellmouths through the bonnet or something...

/cool story hansel