michael Posted February 19, 2004 Share Posted February 19, 2004 So many questions recently.... apologies! I'm just wondering if anyone knows if there are any major differences between the UK and J-Spec manifolds other than the bolt pattern at the turbo and exhaust end? Is the actual manifold itself the same kind of design internally etc? Quote Link to comment Share on other sites More sharing options...
eyefi Posted February 19, 2004 Share Posted February 19, 2004 its the same design, cast log, but whether the ports r the same size?. i have some rubbings of a jap manifold ports which i can scan in if someone has a uk to compare to. Quote Link to comment Share on other sites More sharing options...
dandan Posted February 19, 2004 Share Posted February 19, 2004 Isn't there some sort of bypass pipe or something on the Uk that is not present on the jap one? Relates to the better boost control issue of the uk wastegate design. Not seen one in person but that's what i thought?? Dan Quote Link to comment Share on other sites More sharing options...
michael Posted February 19, 2004 Author Share Posted February 19, 2004 eyefi - I'd love to see a scan of your rubbings dandan - Can you remember your source for this info, if I do go ahead with the swap I certainly don't want to be downgrading anything to a lesser spec, you have me worried now! Quote Link to comment Share on other sites More sharing options...
dandan Posted February 19, 2004 Share Posted February 19, 2004 I'll have a look around see if i can find anything useful. Someone may come along who's had the two side by side and can explain the real differnces. I think that once you've got the hybrids, boost control will be fine on a J spec manifold anyway as the wastegate will no doubt be enlarged slightly. Quote Link to comment Share on other sites More sharing options...
eyefi Posted February 19, 2004 Share Posted February 19, 2004 there's no bypass on the manifold. look here for a comparison of the two side by side. bear in mind the usa log shown is ported, so the question still remains about the size. Quote Link to comment Share on other sites More sharing options...
dandan Posted February 19, 2004 Share Posted February 19, 2004 The pipe i was talking about is visible on the sixth picture on the US assembly. I don't think this is present on the jdm type is it? Edit: Look at 4th pic...no pipe on jdm. Dan Quote Link to comment Share on other sites More sharing options...
eyefi Posted February 19, 2004 Share Posted February 19, 2004 yeah, thats the exhaust bypass pipe that's used to prespool no2, but i thought he was on about the manifold differences. i wasnt saying there was no bypass, just nothing on the manifold. Quote Link to comment Share on other sites More sharing options...
michael Posted February 19, 2004 Author Share Posted February 19, 2004 So this here prespool pipe then.... is this a UK spec only feature that is likely to be present on UK hybrids too or one of those things they leave out when building them? This J-Spec hybrids route seems to be riddled with potential obstacles but I seem to be overcoming most of them, I just don't want to end up with something important missing or compromising power / response for the sake of a pipe or two.... Quote Link to comment Share on other sites More sharing options...
dandan Posted February 19, 2004 Share Posted February 19, 2004 To be honest I don't know if this prespool pipe makes any difference to spool time, response, boost creep or outright power. Also I do not know if a set of jdm vs uk hybrids (of equivalent spec) will produce different results. This is something I have always wondered about, whether to source a full uk assembly to "hybridize" or just use my J specs. Any idea if one manifold is better suited to mild porting? Anyone have any good info regarding this? I guess you're hoping there's no real difference (which is probably true). Quote Link to comment Share on other sites More sharing options...
eyefi Posted February 19, 2004 Share Posted February 19, 2004 the pipe is nato spec, but the system is not. the jap turbo elbow is a different design that uses a slightly different method of prespool. the nato spec uses this pipe to allow some exhaust gas through the no2 and dumps it into no1's exhaust. it cant dump to no2's exhaust cos thats closed during prespool by the exhaust gas control valve. i think the turbo elbow designs are not the best, but very good for the sequential job they have to do. stock, the uk turbos have a bigger a/r for top end, the jap turbine housing has a smaller a/r for response. u can change the a/r by changing the turbine but u cant change the turbine housing (without custom manifold). im not sure what differences the respective turbine housings have. at the end of the day u'd need to get the complete assembly from engine to the first cat. r u getting a really good deal on the jap hybrids? the uk manifold looks a bit bigger to me in them photos, but that could just b an illusion (ooo, ooo, ooo, ooo, ahhh, illusion ). mike, i have a jap one off the car if u can get a uk to check against. Quote Link to comment Share on other sites More sharing options...
MONKEYmark Posted February 19, 2004 Share Posted February 19, 2004 look at eyefi the manifold king michael would it not be easier to get a standard set of uk turbos? ibrar has some. but if you going for more power on hybrids, what sort of power increase would you get from hybrids? and eyefi what you up to on your custom one off job? Quote Link to comment Share on other sites More sharing options...
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