mrgee2jz Posted November 14, 2010 Share Posted November 14, 2010 (edited) Hi there everybody, I've been running a garrett gt4094r for a while now which has a twin scroll housing but I've been using it with a xspower single outlet manifold, ive now changed it to a greddy twin scroll manifold, now as far as I'm aware I should have less lag but I feel as if I have more and it was boosting up a whole 1k later. Also the boost felt more progressive:blink: I did test it in the rain so granted racelogic could have being playing a part in this but it just felt a bit wrong, does anyone have any input in this? Edited November 14, 2010 by mrgee2jz (see edit history) Quote Link to comment Share on other sites More sharing options...
davej705 Posted November 14, 2010 Share Posted November 14, 2010 Have you tested in dry yet? Quote Link to comment Share on other sites More sharing options...
jevansio Posted November 14, 2010 Share Posted November 14, 2010 IMHO you need to do things a bit more scientifically than a bum dyno, a propper data log before & after fitting would have been much better Is your manifold twin wastegate? Quote Link to comment Share on other sites More sharing options...
Jake Posted November 14, 2010 Share Posted November 14, 2010 Have you had the mapping adjusted to correct for the different manifold? Quote Link to comment Share on other sites More sharing options...
Swampy442 Posted November 14, 2010 Share Posted November 14, 2010 You'll need a twin scroll manifold to make the most of a twin scroll housing. Also theres been plenty of horror stories over the interwebsz about running a divided housing on a non divided manifold. Quote Link to comment Share on other sites More sharing options...
dandan Posted November 14, 2010 Share Posted November 14, 2010 In theory the boost should build more progressively and smoothly so that part of your bum dyno is not unbelievable. What's the A/R of both turbo housings? What is the bore diameter of the runners on your old XS manifold and the new Greddy manifold? I suspect the Greddy will be bigger. Also, are the runners a lot longer on the new Greddy manifold? I have seen some where they very very long. Quote Link to comment Share on other sites More sharing options...
Terminator Posted November 14, 2010 Share Posted November 14, 2010 Have you had the mapping adjusted to correct for the different manifold? Quote Link to comment Share on other sites More sharing options...
mrgee2jz Posted November 14, 2010 Author Share Posted November 14, 2010 Ok firstly 1. Single wastegate but 2 pipes go in to 1 further down 2. Not been re-mapped yet, but the engine feels a lot smoother on idle 3. I have heard those horror stories too, but my twin scroll housing was perfect, nothing melted at all, I suppose that's because of the good mapping 4. Exhaust turbo housing hasn't changed, a/r 92 or 90 somthin, always been divided 5. Runners look the same diameter but I will measure when I get out of bed..... 6. Greddy runners ARE longer but not verry long but that's what I was worried about. Also my xs was wrapped. Well half wrapped, the rest fell off... it's been mapped by RyanG on torque developments hub dyno so I have the previous Dynograph @ 641hp wheels and around 740 & crank It will be re-mapped again very soon Quote Link to comment Share on other sites More sharing options...
mrgee2jz Posted November 14, 2010 Author Share Posted November 14, 2010 Have you had the mapping adjusted to correct for the different manifold? Can it make that much difference? Quote Link to comment Share on other sites More sharing options...
mrgee2jz Posted November 14, 2010 Author Share Posted November 14, 2010 couldnt do any more bum tests today as it was raining all day Quote Link to comment Share on other sites More sharing options...
mrgee2jz Posted November 16, 2010 Author Share Posted November 16, 2010 (edited) Ok i did some more tests today, bum tests that is, and i found the turbo spooling up as low as 2k which is great, but the reason it felt soo laggy is, yes it starts boosting lower down but takes longer to get to full boost, it runs .5bar at 3k and i think full boost by around 4 to 4.5k. Like you guys said, i think it can do with a bit more mapping now and it should be positive results old manifold dyno http://www.facebook.com/photo.php?pid=4919599&l=7d8696a45d&id=512096710 Edited November 16, 2010 by mrgee2jz (see edit history) Quote Link to comment Share on other sites More sharing options...
Wez Posted November 17, 2010 Share Posted November 17, 2010 A proper twin scroll setup should spool quicker than single scroll Quote Link to comment Share on other sites More sharing options...
jevansio Posted November 17, 2010 Share Posted November 17, 2010 As it's a single wastegate manifold, this is't a true totally divided setup though? Quote Link to comment Share on other sites More sharing options...
dandan Posted November 17, 2010 Share Posted November 17, 2010 How long is the runner to the wastegate and over how much of that length does it stay divided? Quote Link to comment Share on other sites More sharing options...
mrgee2jz Posted November 17, 2010 Author Share Posted November 17, 2010 How long is the runner to the wastegate and over how much of that length does it stay divided? its about 5 inches and 2 of those inches are actually divided, but its a greddy manifold, surely they know what they are doing, right? Quote Link to comment Share on other sites More sharing options...
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