I would love to see that article. Can you scan it and post it up. I agree if your talking about log-style because the themal expansion causes the manifold to move horizontally which stresses the welds whereas in the pentroof design, it just doesn't have this issue. Can anyone show me a link to where pentroof's have cracked?
Got a link or Do you a pic and size etc and yes if smooth and bigger internal could be the go? Any link to website or pics? I take it they are cast iron like factory so won't crack?
Would we really need a set to copy? These MS manifolds will be at least a thousand bucks, not light either so another $200 freight... and a slight chance they'd be pinged duty. So a minimun of about $1,600AUD. Or near $2,000AUD if they get pinged. We could port the crap out of a stock set. (to a stage they were too thin and would crack) and cast these and simply make them a bit thicker perhaps. or cut up an OEM manifold to use for the casting. Would be cheaper then buying and copying. Less of course someone's going to get a set and perhaps do an aus300zx service before they fit em and allow a casting. Egg
Well if we get 10 or so peeps interested enough, which dosen't seem likely! we could have a draw, wining number get the ms mannies seens fair! But i also like your idea off using stock mannies for a template, much cheeper, and it just might work.
that could be very good... port the stock ones until they get holes in them, and then use that as a template for the cast ones, just beef it up a bit so that the holes get filled and strengthened edit: actually if you look at the pics, the MS ones are so much bigger than stock that it looks like you couldn't port the stock ones enough to get the kinda opening that the MS ones have... qn: when they cast a 3D shape like that, how do they get the centre bit hollow? is it cast into pieces and then stuck together somehow?
I have a set of very heavily ported stock ones here now I finshed a while ago. regardless of what we do. They will never have the ID the MS ones do. I doubt it is going to be anywhere near $2000 to bring em in Paul. I am guessing $1500 if they cost USD $1000 ex Z1. That is cheap for a pattern IMHO. Do you have any idea of the cost of a pattern for these? A lot more than that I can tell you. Lets start another thread about this and move on it. GJ
Cost a bit These MSP ones look the go although bit expensive and are they are not extrude honed and match ported? They probably would not ever crack either? Anyone bought some as we can get them flow tested. I would like to see live or at least a pic of the middle one as this is the most restrictive and where heat starts showing on dyno. They should be better if larger ID than stock but also if smoother and middle runner points towards the turbo so not shoot too much at the opposite wall, then do the turn towards turbo. Do they come with stickers, so if not so good at least you can get a sticker for the huge money paid? Plus get to put on your website an overseas brand name which is snazzy. For the money spent thought they would want to be worth it or may not be any better at all than properly ported and extrude honed factory ones. What power do they flow or flow tests or dyno reading links? They are on the right track though same as the Gibson R32 GTR's back in early 1990's at Bathurst had custom cast manifolds larger ID than factory and had custom exhaust manifold studs.
read last months hpi.. pentroof didnt use them themself in their own freaking zed coz they said they will crack and they wanted the car to be street driven, not so much an issue for a race car as the engine is out every other week for something
But do they? Like to see that and they could but bigger but rough inside they may flow worse and would not be suprised if they were worse btu extrude honed they would probably be beter although who needs more than 450rwkw or has the engine and set up to handle and require this. Although they may make the power with less boost so less heat and stress which is good. Bigger is not always better, such as some Jap cast alloy intake manifolds don't necessarily work better than stock. I know a lot of the after market stainless manifolds flow worse than stock, especially on SR20 motors which the stock ones not even tickled and stock are fairly good. Both flow tested and on dyno.
see this link on ttnet - unfortunately the pics aren't working, but the reaction is very good from the people that did see it late last year http://www.twinturbo.net/net/viewmsg.aspx?forum=general&msg_id=1608783&forum=general&dtSearch=1
ok let's do this i'm taking andrews ported stockies to a foundry near my workplace in my lunch break tomorrow they are going to take a look at the basic manifold for our car and see what's involved in the pattern making etc if it's not going to be a cost blowout, then that means it's feasible, then i'll start shopping around to get competitive prices etc obviously a large component in the cost is the setup costs, so i'm gonna base the feasibility on 20 sets of manifolds :zlove:
Does anyone have last months hpi? To lend or to scan or even just post verbatim what they said? I'm finding it hard to believe that a manufacturer that pretty much guarantees their manifolds NOT to crack would say they are afraid of using them on a street driven Z because they think they will. When kuah was selling them, I believe he said that if anyone cracked them, that he would back his product and was almost positive that he would either get them repaired, replaced, or heavily subsidised and was willing to stand by anything he sold. Also, let us remember that A often gets turned into B in magazine articles eh? Anyone have a link to someone who has cracked them?
ive got it.. tis where i read it.. i think the assumption that they didnt use as they will crack would have come from the writer of the article.. but why would they not have used the manifolds??
Cost? Different objective in mind? I don't know. I just don't get it that they wouldn't use them for fear of cracking, since they pretty much guarentee them, and I can't find a single instance of them cracking and that's not for lack of trying. Here's a few quotes I like: "Also Log manifolds suffer from alot of expansion which tends for them to crack. Also here is something of interest on a log manifold, the temp at the front of the manifold will run many hundred degrees different from the front of manifold versus the back of the manifold (towards the turbo area). The end result is that rear cylinders will run hotter than the front." "I think the quote was "Pentroof has made over 100" And has had none crack yet. So I think that is well proven. I forget I asked Kuah this question before." Carlos Ramirez Not all of the advantages of pentroof style manifolds are increased flow.
cost? haha.. they make/sell the things.. if anyone can afford them they can.. they wouldnt cost them much (probably alot less than porting stock manis) also staino manis dont only crack from heat.. but the weight of the turbo and the vibrations.. SS gets very brittle when welded.. mild steel doesnt suffer this problem
Kuah asked Pentroof about making their manifolds in 321 instead of 304. Their reply was that they higher strength of 321 actually made them more likely to crack. The 304 allowed the pipe sections to take some of the stress through deformation, while the 321 wouldnt, and would concentrate the stress at the welds. Stainless manifolds certainly shouldn't be used for log style manifolds. They simply expand too much. For log-style the currently used materials are cast iron, or inconel. I would love someone to be able to copy the pentroofs, or design similar style manifolds with cast iron, but I think the close precisions required means its gonna be difficult to find someone with the skills. Flex joints in the exhaust should help with the vibrations, and supports for the turbos. The cost/benefit ratio for pentroofs certainly isnt there for most design objectives, but not everyone wants peak hp.
Matt, waste of time just taking the ported Manifolds in to be copied. Unless they increase the bore size of the log by about 8-10mm it will be a waste of time. The turbo outlet flange has to be moved out 10mm to accomodate the bigger log size. It will all still fit. Now if you did those mods via a new pattern then we would be cooking. I think you will find the pattern cost very expensive. But the unit cost quite reasonable. I would say under $100 a pair.
