AFCrain Posted April 21, 2011 Share Posted April 21, 2011 Now I know there's some info on here regarding this, but patience is limited when you're tired and you're eye's are sore from staring at a screen for hours. Here's the question. It's common knowledge that a stock turbo exhaust manifold is great for moderate power ratings, to bad they're ugly. If I were to use a turbo header with a twin scroll turbo would my engine be noticeably effected by turbo lag? I understand the variables involved with the turbo size, header length and size. I'm looking for personal opinion rather than technical advice. Thanks guys! Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted April 21, 2011 Share Posted April 21, 2011 Depends more on the turbo you choose, than the use of a header. I don't know what else to say. The question is to broad.... Quote Link to comment Share on other sites More sharing options...
LoneStarS30Z Posted April 21, 2011 Share Posted April 21, 2011 From my experiences with my previous car I would I would say no, lag wouldn't be worse, but better. On my SR20, I went from the stock log manifold, much like the L has, to a tubular manifold from Tomei and spool came on much faster and power was increased. Luckily, that was an SR, and prices were reasonable and easily attainable. L series tubular manifold seem to be much rarer and definitely more expensive. From what I've seen, you either have to be patient and wait for a HKS manifold to pop up, or have a custom manifold made, which be my latter choice just as its almost guaranteed to be more expensive for a quality job. If you look it up though, someone here was selling a single turbo manifold for around $800 if I remember correctly, if I had the funds available, it would've been mine long ago. Quote Link to comment Share on other sites More sharing options...
AFCrain Posted April 21, 2011 Author Share Posted April 21, 2011 (edited) @RB26Powered~ I realize it's a fairly broad question. I wasn't to worried about exact details, just personal experiences. I've known people who swear by headers and some who strongly believe that it drastically changes the performance just because the tubes on a header are longer compared to the ports/chambers on a manifold. @Lonestar~ Thanks for the input. It is a different engine, but the dynamics should be similar enough too consider the info. I'm not terribly worried about finding a header for sale. I used to be a welder before I joined the military and it's like riding a bike in my opinion. I have some rough plans floating around in my head, hopefully they'll find their way to paper soon though. I'm also going to fab my own intake since I'd like to run a throttle body in 60-80mm range. I'm also strange and like to push my limits with projects like that. I've gotten a lot of great info on custom intakes from browsing around on here. If I feel less adventurous at the time I may end up just modifying a Greddy RB plenum and fitting it to the L series flange. We'll see, I've got nothing but time right now. Edited April 21, 2011 by AFCrain Quote Link to comment Share on other sites More sharing options...
Tony D Posted April 21, 2011 Share Posted April 21, 2011 "It's common knowledge that a stock turbo exhaust manifold is great for moderate power ratings, to bad they're ugly." Yes, I guess if 750HP is 'moderate' and you are planning on building a 1500HP Turbo L28, then by all means go with a header. I would think the breaking point would be in the 800 to 900hp range. Stock or ported US/JDM Spec Log seems to be no hindrance to 638HP, Euro Log well above that point, haven't reached a 'strangle' point there yet it's interior is considerably larger than the US manifold, equivalent to and even slightly larger than the tubular SFP header sold some time ago... Jet Hot makes rusty castings look grand, BTW. And it doesn't cost you $1500. I guess it's more a ricer thing for appearance, eh? Functionally it doesn't seem to matter. Quote Link to comment Share on other sites More sharing options...
Tony D Posted April 21, 2011 Share Posted April 21, 2011 BTW, there once was a magical porter out gate three in Chibana... he did wonderful things with the L-Head, and many of the top racers on the Japanese Mainland sent their heads to him for work. They had an old one-eyed man there that did wonders on flat metal sheets with only a hammer and anvil. I could watch him for hours... Quote Link to comment Share on other sites More sharing options...
260DET Posted April 22, 2011 Share Posted April 22, 2011 All things being equal, a twin scroll will spool quicker and deliver slightly more top end power, definately a good thing. A properly designed equal length fabricated manifold will also improve performance, note the 'properly designed' bit. Quote Link to comment Share on other sites More sharing options...
Tony D Posted April 22, 2011 Share Posted April 22, 2011 Quantify the performance gain versus dollars spent... There was a paradigm that says you 'have' to use a header. But with numbers like posted above...really what kind of gain will you realistically get? And at what cost? There are far too many 'theoretical' rules regarding turbos. People repeat them without much regard to real-world payback. Proper engineering should always balance costs against performance gained. A lot of this stuff really seems to add up to 'incremental' improvements with costs far higher than other things you could do. Quote Link to comment Share on other sites More sharing options...
AFCrain Posted April 22, 2011 Author Share Posted April 22, 2011 "It's common knowledge that a stock turbo exhaust manifold is great for moderate power ratings, to bad they're ugly." Yes, I guess if 750HP is 'moderate' and you are planning on building a 1500HP Turbo L28, then by all means go with a header. I would think the breaking point would be in the 800 to 900hp range. Stock or ported US/JDM Spec Log seems to be no hindrance to 638HP, Euro Log well above that point, haven't reached a 'strangle' point there yet it's interior is considerably larger than the US manifold, equivalent to and even slightly larger than the tubular SFP header sold some time ago... Jet Hot makes rusty castings look grand, BTW. And it doesn't cost you $1500. I guess it's more a ricer thing for appearance, eh? Functionally it doesn't seem to matter. Touche, Tony D! Even after all the time I've spent here it was my impression that the stock manifold was good until 350-450hp range. Which just so happens to be my desired goal. And I guess you'd consider old school JDM ricer? I know I don't have may pics, but that's the overall look I'm trying to achieve, with of course some modest new age upgrades. I'm a fabricator at heart so I love to play with metal and see what my limits are. BTW, there once was a magical porter out gate three in Chibana... he did wonderful things with the L-Head, and many of the top racers on the Japanese Mainland sent their heads to him for work. They had an old one-eyed man there that did wonders on flat metal sheets with only a hammer and anvil. I could watch him for hours... You mind parting ways with the name of this guy? I don't have much time left before I'm off to the sandbox...again Thanks again for all the info, guys! Quote Link to comment Share on other sites More sharing options...
Tony D Posted April 22, 2011 Share Posted April 22, 2011 It was RS Okinawa, any L-Gata guy on Okinawa can send you to him. I never knew his name, I never had work done by him. I just waited for the scrap heads to be loaded on the truck and followed them to the scrap yard. Then I bought the damaged heads for scrap value (about 1000 yen each at the time) and have since resurrected three of them with bills well under $250 each---most for welding repair of dropped spark plug electrodes and some water jacket perforation when porting! Old School JDM (which I lived through firsthand) also included an eerily stock looking HKS Cast Manifold Log of Stainless Steel and external wastegate configuration. The turbo and manifold is hidden under the ITB's and Surge Tank anyway. Unless you got an RHD that can take one of the old takeoff R32 Turbo manifolds...and as we all know that is mostly a 'rice' addition as a single is just as efficient in that horsepower range. You really need to look at JeffP's Extreme 280ZXT Page on Anglefire, he was at 450 to the rear wheels on the stock manifold, and since then has far surpassed that point. You can spend $1500 on an old manifold that wont get you anything in terms of performance (RICE RICE RICE) or spend that same ammount on nice new CLASSIC JDM OLD SCHOOL looking 15X8 or 16X10 Watanabes.... I know where I'd spend the money: Wats all the way. The manifold is really a red herring, you really can spend your money on things which will give you far more payback. Hell, that $1500 could get an ITB setup out of Australia (or darned near close to it!) That would be far better than the old header. See you in the Sandbox... Das Island is on my schedule. Moldy shower, stained sheets, and no water before 1200... Gotta love camp living eh? And you thought you would get away from it when you left the war! LOL AFSC? or MOS? Quote Link to comment Share on other sites More sharing options...
LoneStarS30Z Posted April 22, 2011 Share Posted April 22, 2011 Tony, happen to know if those guys are still open there in Oki? I'll be there in June and hopefully the Z later in the year, would LOVE to just be around the guys and learn some stuff and let them take my money. Never heard of a stainless steel log manifold, sounds interesting. Quote Link to comment Share on other sites More sharing options...
Tony D Posted April 22, 2011 Share Posted April 22, 2011 ain't been there in 26 years, I got no clue dude... Quote Link to comment Share on other sites More sharing options...
Cannonball89 Posted May 24, 2011 Share Posted May 24, 2011 On my N/A L24, the headers seemed to hurt performance at low RPM, but did help the top end a little. The thing I loved most about the headers was how awesome it sounded with my twice pipe exhaust. On a turbo motor, I figure that the sound will never be the same as an N/A with headers just because of the muffling effect of the turbo, so the only advantage I could see for a turbo street car making 250-400HP would be the look of a bundle of snakes going to the turbo, but on our L-series motors you can hardly see the turbo with the intake being over it, let alone the manifold going to it, so I don't see any justifiable reason for a turbo header on a car making moderate power, like Tony said. If our L-series engines had the intake and exhaust on separate sides of the engine like modern engines, then I might consider spending money for a turbo header for the look of it and the possible slight performance gain (because street cars will naturally be shown at car shows, I don't really consider it "rice", more like "showing off") I'll just be happy to be driving my car again, I'm so close to getting my car driveable again, just keep hitting minor roadblocks like my LC-1 crapping out making it impossible to tune... Quote Link to comment Share on other sites More sharing options...
letitsnow Posted May 25, 2011 Share Posted May 25, 2011 Has anyone(Tony or others) done any comparative or back to back testing with a stock manifold and a tubular/equal length/twin scroll/whatever header that they would be willing to share? I'm curious if there is any data to show a benefit to one or the other(ignoring the cost difference), more power at the same boost, change the shape of the curve, lower EGTs, etc. Quote Link to comment Share on other sites More sharing options...
cgsheen Posted May 25, 2011 Share Posted May 25, 2011 I'm also kind of interested since my sons know a designer/fabricator here in Phoenix that has expressed interest in designing a manifold for L28ET's. (He used to work at Full Race as one of their lead designer/fabricators) My youngest son and I (both with turbo swaps running) keep telling my oldest son that there's no reason to have him build us a manifold (which he would probably do for cost of material) because our stock manifold will handle the horsepower we plan to run. He says there are other benefits beyond horsepower and we're NUTS not to let this guy build us a manifold - but I don't really understand them. Are there other benefits like how and when the turbo spools? Are we crazy for not having this guy fab us up a manifold for what is likely to be very cheap? Or will it mostly be "all show - no real go"? We're probably never going to build our Z's past 300 horsepower or so... Quote Link to comment Share on other sites More sharing options...
Tony D Posted May 26, 2011 Share Posted May 26, 2011 Seriously, if you can make 700 on the stock manifold.....exactly what kind of performance increase (and it will have to be incremental) that you are willing to spend $1500+ to achieve? "Other benefits beyond horsepower"---have him spell that one out, put it on paper, and have him pay for the dyno time to prove it or give you your money back if it doesn't live up to what he claims it will give you. Other than his pocketbook... If you aren't going past 300 you aren't going to get any significant gains going tubular! Even if you are, until you are near 600 it's sketchy even then! If I had a stock L28ET, and wanted to spend $1500 on it to get SIGNIFICANT horsepower from a GTX35R Turbo I fantasized about putting on, I would spend it on HEAD WORK AND A CAM. If you don't have SERIOUS head work and a cam on your engine, putting a tubular header on your engine is just ricing it up, plain and simple. And even then, up to 600 someone would have to show me the gains. REMEMBER JeffP HAD a tubular header on his car and WENT BACK TO THE STOCK ONE when he found out it was STEEL and could be welded to accommodate an external wastegate! The Tubular header was more trouble than it was worth. There went $1200 down the drain and countless hours of rework, redesign, and rethinking this tubular header paradigm... Quote Link to comment Share on other sites More sharing options...
FricFrac Posted June 1, 2011 Share Posted June 1, 2011 Guys are running rear mounted turbos on various cars. Has anyone bothered running a N/A header on a turbo setup with a S30 or S130? Personally I'll be running a port matched stock log.... Quote Link to comment Share on other sites More sharing options...
Noddle Posted June 1, 2011 Share Posted June 1, 2011 If you don't have SERIOUS head work and a cam on your engine, putting a tubular header on your engine is just ricing it up, plain and simple. And even then, up to 600 someone would have to show me the gains. REMEMBER JeffP HAD a tubular header on his car and WENT BACK TO THE STOCK ONE when he found out it was STEEL and could be welded to accommodate an external wastegate! The Tubular header was more trouble than it was worth. There went $1200 down the drain and countless hours of rework, redesign, and rethinking this tubular header paradigm... http://www.angelfire.com/extreme/280zxt/page11.html I have this book marked, because it good. Nigel Quote Link to comment Share on other sites More sharing options...
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