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heres a pic of my new highmount manifold made from 316 stainless, it was designed and made from scratch and i think it turned out Quite well, the wastegate pipes still arent on... hopefully the design shall prove successfull and the car can run some good numbers..

on the subject what is the generall conscensese about how far the stock gtr ecu can go.. i have had mine remapped to suite 550cc injectors, but i still have stock afm's... i personally think this should suffice to aroun 320rwkw and thoughts??

cheers all..

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Hi S13Drifter, I don't think you can say the R32 ECU is OK for 299 rwk but not 301 rwkw. Their are simply things that you can't do, inlet air temp versus boost for fuel correction. Remapping the voltage ramp for larger AFM's, you can do it but it takes hours. Acceleration enrichment for rpm ranges. Ignition correction versus boost for engine temperature.

There are a pile of things that you have to start doing when the power gets up that you either can't do or it is uneconomical to spend the time doing it. What takes hours on the std ECU you can do on a Power FC in seconds. If you are paying someone $60+ an hour you can see how it quickly mounts up. If you are doing the mapping your self, it may be a different matter, I have seen one guy spend a whole weekend redoing the temperature correction. I have better ways to spend my time, but IT guys are like that.

I have never run an RB with a high mount on the std ECU. I have a rule of thumb that says if I am going to spend the time and money doing that, then it's time for an ECU upgrade. Particularly with the availability and prices of Power FC's these days I see no reason to delay it.

Hope that helps

Very nice looking manifold, have the welds been polished out, or did you have the sections mandrel bent to suit.

I assume you will be running twin wastegate outlets joining for the one wastegate? And good to see the manifold has been gusseted, as my manifold has already been ceramic caoted, i have made a hanger arrangement that supports the turbo/manifold off the head.

Oh and if you want some cheap RB20 AFMs then i have a couple in good order.

Nice looking manifold...

Does anyone know the firing order of the RB26? Is a 1-2-3/4-5-6 grouping for a twin scroll turbo going to work with the firing order of an RB26??

I dont think turbo engines are all that sensitive to all the acoustic/exhaust pulse/wavelengths etc etc tuning mumbo jumbo like NA exhausts/inlets.

Perhaps the packaging of trying to collect cylinders, say 1,3,5 & 2,4,6 offsets any possible gain thru additional bends or tighter bends, or longer tracts??? Maybe its a best case sceanrio thing???

I dont think turbo engines are all that sensitive to all the acoustic/exhaust pulse/wavelengths etc etc tuning mumbo jumbo like NA exhausts/inlets.  

Perhaps the packaging of trying to collect cylinders, say 1,3,5 & 2,4,6 offsets any possible gain thru additional bends or tighter bends, or longer tracts??? Maybe its a best case sceanrio thing???

Quite possibly :) I really have no idea, which is why I asked...

Two things though:

1. It may not affect a single scroll exhaust wheel like most, but surely it would have a detrimental effect on a twin scroll? :confused:

2. B-Man had problems with his exhaust manifold grouping and pipe lengths didn't he?

Andrew, if you are referring to the old (new) turbo, then no - it was the either the compressor or exhaust fin pitch. We just couldn't get any more out of the turbo. I don't think there was a problem with the manifold.

ie 14 PSI - 250rwkw, 19 PSI - 255 rwkw

I understand that the turbo has new wheels on it now, but I didn't want to be an R&D car.......

Should be a different story with the HKS & highmount now..... :yum:

thanks for the replies, i never really thought of the firing order, i cant see it as being paramount as you can use log manifolds and such with success on turbo cars, as this is what hks originally supplied with the t45s kit... any thoughts appreciated

ROY; yeah its all made from mandrel bends but the welds were polished out were the bends joined..

yeah when i read steves thread i got all scared and worried thats why im still unsure to the success i will have, not long now and we can see, SK thanks for the info, i know its true ive spent time and effort on this part i need to get all the auxilary systems up to the same standard... i always had plans of getting a powerfc (nearly ordered one last week), but lately i have heard lots of good things about haltech. i have used them before the only worrying factor is that they have never been widely used on gtr's theres only one gtr that uses one its in NZ..the ecu itself has stand out features so im unsure as what to do...

its a hks t45s, however stock those turbos came with a 1.12 ar rear housing which is far to big so i downsized it to a .87 ar, and i also had it machined to take a 70mm h trim garrett wheel instead of the 66mm ones they come with... just trying to make it more responsive yet have a good top end. it was a real dog when i got the car the log manifold that the kit came with was cast and had a small leak, and the turbo with the larger housing never saw boost untill 6000rpm and then we couldnt get more than 13psi from it due to the exhaust leak..

I dont think turbo engines are all that sensitive to all the acoustic/exhaust pulse/wavelengths etc etc tuning mumbo jumbo like NA exhausts/inlets.  

Perhaps the packaging of trying to collect cylinders, say 1,3,5 & 2,4,6 offsets any possible gain thru additional bends or tighter bends, or longer tracts??? Maybe its a best case sceanrio thing???

I personally believe that turbo engines benefit from measures such as tuned length extractors, well shaped and flowing heads, large camshafts etc. similar to a naturally aspirated engine. But since turbo motors produce ample power most people don't consider these things. Turbos can easily compensate for poor intake/exhaust design, low flowing heads etc, but unless you are wanting to extract more power (or the same level of power more efficiently) these "minor" issues don't get addressed.

s13drifter: the manifold i have just had built ive gone along the lines of what steve has said, to have short runners and make it speedway style in a sense

btw how much boost will u be running through the t45?

I personally believe that turbo engines benefit from measures such as tuned length extractors, well shaped and flowing heads, large camshafts etc. similar to a naturally aspirated engine. But since turbo motors produce ample power most people don't consider these things. Turbos can easily compensate for poor intake/exhaust design, low flowing heads etc, but unless you are wanting to extract more power (or the same level of power more efficiently) these "minor" issues don't get addressed.

Well when i got the new manifold i agree there was a big difference to how the car drove off boost and at light throttle positions, but just how differently would the car preform between the manifold setup i have( from memeoery its a kinda 6-2-1 setup), and the HKS style with equal length runners???

Back in my "Commodore Crazy" days, different extractor/exhasut setups resulted in sometimes lower torque :(

...your right, unless you are a mechanic with the equipment to do things, the effeciency thing is sometimes prohibitively expensive, easier to wind in a bit more boost and fuel, then to lower reciprocating mass, and preform head work.

Oh and s13drifter... are you going to do any coating, ceramic/HPC etc of the manifold. If mine ever comes off its going to get wrapped in some pyjamas to try and further drop temps, even with ceramic coating she gets warm in there. :)

kamakazie- im looking at around 22- 24 psi, this should be light work as the turbo is claimed from hks to be efficient to 32psi put that was in originall form with the huge rear housing!!

Roy: yes im goin to have it hpc'd eventually just not right now i cant afford it at the moment due to saving for a power fc. cheers all

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