Drock

hi there.. just curious some feedback.

in my area there is someone selling never installed set of OBX long tube headers..

first off.. i dont know much about OBX.. i assume its a cheap brand like Megan etc..

anwyays aside from that..to my understanding long tube headers is basically running catless.. which would give up alot of back pressure..

I am currently running a vortech setup with OEM headers, Berk HFC, ichiba ypipe and tanabe exhaust..

so im wondering if long tube headers would be a good replacement..by removing my oem headers and Berk hfc's..

but at the same time.. may not be good.. cause may lower boost from less back pressure etc...

so thats why im looking for some insight.. if anyone runs with long tubes with a SC.. or if its something you just dont do with SC setup..

thanks
TOny..

mafoor

iTrader: (17)

IMO keep the hfc's and get a set of dc headers if u really want to do headers. I had crawford headers and megan racing resonated test pipes with an AAM Y-pipe and AAM 3" single on my vortech and it was LOUD and raspy as hell. I switched to the Motordyne xyz pipe with the hfc and it sound sooo much better.

juicinjake

iTrader: (6)

im going centrifugal blower with longtubes. id snag the PPE's if you are gonna do it. thats what i did. they have proven gains and are reported to sound good by existing owners. u have to realize though, a lot of cars rasp with longtubes... I should have my set pretty soon and will let you know how they sound with a motordyne TDX2.

Drock

hi..

yes sound/rasp would be a concern.. cause with my current setup car sounds amazing..

but my concern is a reduction in boost.. due to less back pressure.. by using long tubes..

yes im running on a vortech setup..

so im surious if there are others with Vortech setup.. and using long tubes. or if its not recommend..

juicinjake

iTrader: (6)

take any other engine, any other make, like the lsx and mustang guys for example... serious and max effort guys are using longtubes with centri's. vq35's aren't any different. loss of boost pressure isnt an issue so long as power doesnt drop. its always a good thing when you increase flow to the point you make more power with less boost. you wont know if that's the case until you try it. that said, if you do end up loosing enough boost for it to cause a drop in power, raise it back up with pullies (a bigger crank pulley would be preferable as it would give you more wrap. once you get back to the same boost level as before you will no doubt have more power.

binder

iTrader: (8)

boost means nothing. The ricers of the world have destroyed people's brains with the thought of "boost pressure=hp". Boost pressure just means backpressure or resistance. If you run say 10lbs of boost and you put a free flowing exhaust you will reduce backpressure (boost) but you are NOT going to lose power.

Another example: you run a 62mm turbo at 18psi of boost pressure. Now run a 67mm turbo with 14psi of boost pressure. The larger turbo has more flow but less resistance so more power is made at a lower boost pressure. So all boost pressure numbers are not equal and it doesn't directly relate to power. All things perfectly equal then more boost means more power. As soon as you start changing things then it's not directly related. Therefore bench racing between racers is just pointless. "i run 18lbs of boost and you are only 10lbs of boost so i'm faster" yet they forget that the 18lbs of boost is on a an evo with stock turbo and the 10lbs is on a big block chevy.

There are benefits of long tube headers but at stock block power doing headers with test pipes will yield essentially the same power as long tube headers. So you can just get rid of your cats for test pipes and get nearly the same results.

mafoor

iTrader: (17)

Its been proven that vortech setups like some back pressure

https://my350z.com/forum/forced-indu...g-results.html

juicinjake

iTrader: (6)

just to clarify, what i am referring to here is the effect lowering back pressure due to the removal of a RESTRICTION. this is different than losing backpressure due to over-sized tubing killing exhaust velocity, which i talk about below.

right! i remember this post. based on the research ive done on this topic, it seems like a lot of it has to do with the actual exhaust section diameters (from headers to catback) and not necessarily the header configuration (short or long tube). anything that is going to hurt you in terms of excessive tubing cross section and therefore decreased exhaust velocity on an NA car would likely hurt the supercharged car for the same reason (i.e. a dual 3" exhaust on a stock DE). this is why tony has the TDX2 setup as a 2.5"->3" in the standard configuration (with dual 3" front section being available for the big power turbo guys only). its all about increased exhaust flow and scavenging. since the 1-3/4" non-stepped PPE's make equal low-end to the momentum headers and art pipes (which have been shown to gain over stock manifolds and cats) and then substantial gains from 4000-6500, i believe this makes them a prime candidate for a centrifugal blower build. this set of headers coupled to a TDX2 would be the ulimate setup imho. this is why i bought it and why i am recommending it. you are increasing exhaust velocity and scavenging with this setup, not killing it... and that is why it is going to work well!

Resmarted

iTrader: (2)

+1


This forum throws around ideas of back-pressure like a kid flings dirt. No sense, no logic just ideas and random crap.

Tube sizing and scavenging are what help make power in an NA or SC setup. Just like on an NA car, if you run too large of an exhaust on your SC car, exhaust velocities slow down. Heat has a part of this. You don't want an exhaust too small, but you also don't want one too big.
Longtubes will make you more power than a catted short tube setup (provided the pipes are properly sized and the collectors are of comparable quality).

There is more 'area' in the piping for longtubes but it works a bit differently. Primarily a greater exhaust gas velocity (and improved scavenging) are created because the exhaust pulses have more time separated before they crash into each other. A properly designed longtube system (and collector) will use the pulses to essentially pull each other out (aka scavenge). This can show a reduction in torque and move the powerband right in some cases and in others left. It's all varies greatly part by part.

OBX isn't complete garbage, but it isn't the best. Megan uses sched 16 and this isn't the thickest but it works and lots of cars run that thickness without issue. In fact from what i've seen, the stainless they use is actually pretty good quality, low magnetism etc. I assume obx is similar. Fitment would be the biggest question, and with something like longtubes that can be a big big issue. Longtubes are not easy to install, and are structurally more prone to breaking just by their design. So if the headers are properly shaped and fitted well you shouldn't have much to worry about, but if they're not you could have serious cracking etc issues down the road.

Voboy

iTrader: (58)

Long tube headers plus motordyne xyz with cat... Or just stock +art and xyz +cat. Tony has said sc's like a little back pressure compared to n/a and turbo setups. There is a thread on here with a guy that made decent numbers from an sc with the md setup

jerryd87

iTrader: (4)

people claiming sc like a little back pressure dont really know what they are talking about............ no engine likes back pressure its a misconception of people who think proper scavenging = back pressure but its not the case. more air out means more air in plain and simple.

like resmarted said the tubing needs to be sized correctly though or velocities will be down which results in less air out.

if anyone wants to argue go ask a drag car running a supercharger what they use for back pressure............. you will be immediately laughed at so hard you will wish to leave.

want to try and convince me other wise? produce a dyno comparing back pressure numbers(hook up a boost guage in the collector somewhere.) but i can tell you right now no matter the setup the lower the back pressure the more power you will make all else being equal.

if your loosing power its because your not running the proper sized blower and need to step up the boost for more power or the blower size to put it back in its efficiency island, its no different from a turbo there will be different efficiency islands for various impeller speeds and boost pressure. at worst you will reduce back pressure which results in lower boost pressure from the same airflow and loose efficiency but maintain the same power level from efficiency loss dropping it but freer flowing exhaust allowing more power negating each other.

if they liked back pressure then top fuel engines would weld in silencer cones into there zoomies.............. although the massive force they push out would probably destroy the mesh.

CoobcioPL

Power gaines after instaling OBX header in Procharger 9PSi setup (Engine power not WHP)

Z33Garage

iTrader: (3)

Am I stupid and reading it wrong or did both TQ and Flywheel HP go down with OBX?!?

0jiggy0

iTrader: (13)

Run 1 is with the long tubes.