tommis85

Although because my Cat does't have a flange plate at each end I'm gonna have to drop a whole chunk of the exhaust and run it off the dumps That RB melody hehe

That would be the plan

Gents, thanks for the replies I've been doing some more reflecting and have remembered another little detail that would back up the excessive back-pressure theory: When I drive off, it is very quick to make about 4-5psi before it just goes spongy and boost level creeps up with RPM. I'm thinking that this would be because of how the back pressure builds up in the front pipes / front portion of exhaust before the cat etc. There's enough flow to ramp the turbos up quickly to that 4-5psi and then they have to start pushing fumes down the exhaust harder and harder. It would seem to me that so far it's only the ceramic turbos that have been able to survive in this high backpressure environment because they don't need much flow to make boost. I mean hell, they were able to make 14 pounds with the stock exhaust system haha. Really hoping this theory is right

Haha yeh guys stop scaring the &^%$ out of me! The ones I got are the direct bolt ons with part number 707160-5009 and I got them with 15.6 pound actuators (and they sure feel like it but should probably test their psi). Regarding the timing - I'm thinking that Mercury would have checked all this Hopefully... I've done all my turbo installs myself and all the gaskets match the pipe inner diameters. However, I do have one question for you guys - what's the general consensus on split dump pipes? I'm using a set of x-force ones....and I'm about as suss of those as I am of my apparently clogged up cat. It would be nice to see exactly what sort of airflow happens inside those pipes - I bet it's turbulent as fark lol. ....ah the long process of ruling things out

Haha no worries...well, first order of business will be to replace the cat then. Second order of business would probably be a larger cannon muffler that matches at least the internal dia of the piping. Those two things should really help improve the situation!

Ah ok fair enough...well mines a locally made 3.5" mild steel job. I sure hope they didn't weld any restrictors into it! Also, while we're talking restrictions - I do believe that the intake of the cat could be smaller than it's exit...what Mr Stabby was referring to.

Yeh from what I know the -9's shouldn't be too much later than the -7s (which I nearly ended up buying btw). However, there's quite a big difference with 16psi by 4000 and maybe what, 8-10psi by 4000? Shocking! I could check the actuators however I'm running very firm ones - they should be at least 1 bar from memory. They're definitely not cracking open prematurely..

Thanks guys, looks like we all agree where I need to start. Mr Stabby - yep, I'll get it booked in ASAP because for all that I know that thing could be completely blocked up (judging by all the crap that I wash of the rear of the car) Nismoid - yes it must be something like that. The most narrow part of the exhaust would be inside the straight-thru canon though...everything else should be ok (apart from cat) although the system does have some unnecessary bends in it.

Yeh it probably is the culprit or one of them. But the spanner in the works is that my ceramics were venting into that very same system with the same cat and were maxing out But then and again...ceramics can work well in a restrictive system being stock spec and all. Maybe the new turbos need to be totally free'd up?

Hi all! Thought I'd throw my question up here for all the experts out there. My story is that I've just had my brand new GT2860-9 turbos tuned on my R33 GTR only to find that they didn't meet any expectations. Infact, the car makes no more power than with the ceramics even though a massive amount of boost was dialed in! The car made no more than 250kw / 340hp at 18 pounds although it has all the minimum upgrades that all the cars in the "dyno comparsion thread" have on here. http://www.skylinesa...l-dyno-results/ The average power that one is meant to achieve with -9's (or GT-SS turbos) is about 300kw/408hp with approx 18 pounds (that's taken from the spreadsheet in the above-mentioned thread) The turbos made full boost by an excruciating late 5500-6000rpm which is absolutely shocking by any GT2860 standards. The throttle felt like it was made from rubber and all the prior ceramic turbo response is gone.....ie, full boost by no later than 4300 or so. If any one could offer some feedback on past experiences with GT2860 turbos that would be great. Please don't rub in your figures tho - trust me, I've probably already read them in the comparisons / results thread Here are my basic mods: Haltech E11v2 ecu tuned by Mercury Bosch intank blah blah Nismo 600cc squirters Splitfire coils Xforce split dumps with divider taken out because the -9s have their own 2.5" front pipes 3.5" main system with old cat (i'm suspicious of this and how much flow it's blocking) Normal canon at rear Pods Adjustable cam gears (that they weren't able to do much with power gain wise) If anyone could give me some feedback on what might be going on here that would be great. Please note that my car made about 330-350hp with the ceramic turbos on the same exhaust setup (minus injectors and cam gears) and also made 375hp with a set of used R33 N1 turbos. It's these past figures that make the new ones with the -9's seem so frustrating!

^^ I'm up for this

Ah ok mate, I'll let you know if I end up needing one when I put the terbs on

Hey, I'm assuming you make these for both the R32 and 33? It looks as though the ends where rubber hoses slip over look a bit different etc

Ah that's the way peoples....looks like the -9's are the turbo of choice for a mildly modified GTR hoping to break the 400hp mark. Yeh it's the falling over in the top end that makes the car perform so pitifully once you're past 1st and 2nd I'll be putting these in with a set of cam gears and injectors (already have computer, pump and coil packs along with zhorst etc...so all the basics) As for the TT pipe mod, I'll see how I go first and then go from there as a lot of people have said on here that there shouldn't be shuffle with these. Some say there will be some but they're also running much better/higher-flowing intake plumbing / hard pipe setups (i think...from memory). I'll be running all stock plumbing for now so see what happens. Will have to enter my results into the turbo upgrade thread on here ;-) Leviboy, you wouldn't happen to recall by how much you changed your intake/exhaust cams by with the gears??

Good good

Those are some pretty impressive figures too! Is she still a 2.6? Just wondering tho - how would you compare the response of the -9's to the standard ceramic terbs? Mine are in the post now and am hoping that they're not going to be too big for around town driving...

That's the way, so I take it that it got rid of it completely? I'll be sure to be back on here in a flash if I get some suffle ;-)

I did it on a dead flat concreted area...and even did it on another area just to double check. But then, when jacking the car up she's noticeably heavier on the front driver corner. Yeh you gotta love them...I have mine set to about 15/30, so medium setting and she's good around town....could even soften her a little more but that means taking the parcel shelf out again

Yeh I went around and measured each corner from 3 points on the car till I finally got front level and rear level....took ages man! Yep I did get one but it didn't improve things much - there isn't much to adjust on and a stock GTR steering setup =/ They were able to change general alignment and toe but when it comes to castor and camber corrections there's not much that u can do

Yeh they look quite fun on the video....bed she pulls pretty hard in 2nd

Hey mate, thought I better post up in this one instead of the shuffle thread ;-) I see that you put some BC's in her - I got some of those the other day too and put them in on the weekend. Just wondering if you had any issues with getting the car to sit level at the front seeing that the things a lot heavier on the driver's side?? When I installed mine it started to want to pull to the left and now I'd probably need some adjustable castor arms etc to correct it. (or put it up a bit higher again)

Ooh a build thread nice work! Yep agree with what you said in it - always more fun in a threesom ;-) You still happy with your -9's? I'm assuming they leed a shuffle-free life??

So do you think the new tune made it go away or was it the TT pipe mod?

Ah ok, I'll will have to have a look. If I do get some shuffle I'll have to look into that TT pipe mod as well - there seem to be a couple guys on here who've nutted out some pretty good designs.

I concur with ya there....that's definitely the BOV's - I can make that happen with my stockies....especially when you're driving over a long crest and you gentle let of the gas to maintain constant speed. If you're running a bit of boost you can make it go on for ages... From all that I've read now....and what people have kindly submitted on this thread, you definitely SHOULDN'T be getting with -7's and factory intake piping, turbo-to-cooler piping and stock, plumbed in BOV's.