Jump to content
SAU Community

Recommended Posts

Hi everybody

Looking to upgrade the inlet manifold on my rb30dett and just wanting to know if there's any options beyond hypertune out there that might fit my requirements. Specifically:

1) I definitely will be retaining the 6 x ITBs.

2) I want to run a 100mm/4" inlet diameter, in anticipation of going to a full 4" intercooler and turbo outlet system once I convert to a single turbo.

The last time I looked into this hypertune seemed to be the only item that could meet these requirements but I thought that since then something else might have entered the market. I basically want a nice big plenum with a quality, machined face to bolt on, seals properly, that flows nicely and distributes flow to the rear cylinder. The hypertune price range would be the upper end of what I'm hoping to pay and if anyone can recommend a good Australian distributor that I can chat to that would be great.

Also, are there any issues I might have particularly with a deck height that is now +38mm, eg: clearance with clutch mcs etc - I'm already assuming I may need to go to an r33 style clutch mc. I am currently running the factory fuel rail with 1000cc injectors but all the ones I've seen have factory mounts for the rail as well. But any other tips on clearances and fitment etc would be greatly appreciated. Thanks in advance.

4 inch intercooler pipes? Man... What's wrong with the 80mm?

Am currently running 22-23psi on a set of HKS 2530s. It has a built rb30 bottom end and big cams, so when I go to a single turbo (around t88 size or so) I will be upping the boost considerably.

EDIT: this is not intended to be a street/daily driver car.

Edited by dorifticon

Also, at what power level do ITB's become a hinderance over single?

CPC, custom plenum creations do plenums. So do RIPS in NZ. Both would make what you want.

Or modify the stock plenum, don't quote me, but RACEPACE did/do that?

The ITB's will always disturb the airflow and create a pressure drop across the port compared to a single TB manifold.

If you just want to make big power and less pressure drop through the system putting a single TB on the stock plenum is the cheapest way out.

If you are serious, a much larger volume plenum (which helps with distribution of flow) with a 100mm TB like you want is probably better and big piping, no flow restriction!

  • Like 1

The more boost you run the smaller the piping needs to be. Unless you are chasing over 600kw I would leave the stock piping in place.

Currently on 385kw or so (at the treads) but turbos are way undersized for my application. Would ultimately like to get into the 600's once fuel system (including switch to ethanol) is sorted.

The ITB's will always disturb the airflow and create a pressure drop across the port compared to a single TB manifold.

If you just want to make big power and less pressure drop through the system putting a single TB on the stock plenum is the cheapest way out.

I don't want to lose the off-throttle response or the effect of the brake booster on sudden switch from throttle to brake. It's one of the things I like most about the rb. I realise it makes tuning a PITA and may limit power, but have driven a single throttle and it's not for me.

Thanks for all the names/etc so far, will continue the research.

Currently on 385kw or so (at the treads) but turbos are way undersized for my application. Would ultimately like to get into the 600's once fuel system (including switch to ethanol) is sorted.

I don't want to lose the off-throttle response or the effect of the brake booster on sudden switch from throttle to brake. It's one of the things I like most about the rb. I realise it makes tuning a PITA and may limit power, but have driven a single throttle and it's not for me.

Thanks for all the names/etc so far, will continue the research.

That quote about smaller piping wasn't right, I am not sure what Scotty meant?

In any case, you can upgrade the piping but the biggest restriction will probably be the ITB's, in which case, the money spent upgrading pipe work is best done elsewhere. Unless you do change it anyway to go to a big single turbo then by all means upgrade to larger piping, but you will most likely on get a small gain in flow (less pressure drop) through piping.

That quote about smaller piping wasn't right, I am not sure what Scotty meant?

Have seen 500kw through the stock piping, now he is going for 600kw. I will let you know how he goes.

After seeing 350kw through 2.25 inch piping, 80mm should therefore easily flow 600 by my books. Just letting you know as most workshops would have upgraded it at much less power. The more you compress the air the smaller the pipes need to be, that much is obvious yeh?

perhaps the word boost should be replaced with air volume in this topic? since there are so many things changing in this setup (turbo, intake manifold, intake piping, power output) throwing around estimations and requirements for boost levels is pretty irrelevant.

no one is doubting 2.25 inch piping wont flow big numbers, i think the question should be 'is 4" piping worth it?' smaller piping flows less (or requires more boost) and dissipates less heat. probably not worth the effort to fit 4" though especially if it limits your plenum choices.

If the turbo outlet is only 2.5in why would the rest of it need to be 4in?

The turbo outlet is only 2.5" because the size of the compressor housing is such (diameter, thickness) that you couldn't easily make the outlet bigger. On top of that, centrifugal compressors basically work by turning air velocity into static pressure. The velocity in the compressor housing is very high, and you want that to slow down as gradually as possible (hence the shape of the volute of the housing). If you tried to take that same compressor housing out to, say, a 3" outlet, then you'd either have to be less gradual or make it a lot bigger (longer in the outlet). This would make for poor performance on the one hand and poor packaging on the other. I think we should ignore for the moment the fact that most such turbos then get installed with a nasty elbow directly off the outlet.

But the velocity in the 2.5" outlet is probably too high for good pressure drop characteristics if you were to keep the pipework at 2.5", so it make sense to go up to 3" or whatever is needed to get the air velocity back into a more reasonable range. And of course people will argue about what a sensible velocity range is and they will argue about what power level = what boost = what airflow without paying any attention to the type or size of engine or turbo. But we'd best ignore that too!

  • Like 1

no one is doubting 2.25 inch piping wont flow big numbers, i think the question should be 'is 4" piping worth it?' smaller piping flows less (or requires more boost) and dissipates less heat. probably not worth the effort to fit 4" though especially if it limits your plenum choices.

the piping setup in my 'R needs to be changed anyway, when I got the extra 38mm deck height from the rb30, I did a "temporary" hack and clamp job to extend the OEM rubber pipes and was never super happy with it. So this incremental cost of upgrading the piping (especially in light of everything else) should be not much. There's going to be a lot of pipe cutting and welding in any case for the single turbine setup.

In terms of whether it will be better or worse than the 80mm setup, I figure the stock power on a GTR was in the 200's, so upgrading the cross-sectional flow area by around 60% shouldn't be a bad thing if chasing power levels that are well over double the stock output.

Power should be slightly better if there aren't extra/tighter bends in it, and transient response will be slightly worse I imagine. Bang for buck it may be a waste, but that's for you to decide. Depends what you plan to use the car for.

Just remember stock boost is only one bar too, you will be running twice that most likely, so the pipes should flow around 50% more air from that alone, and the factory pipes were overkill for stock power.

Have seen 500kw through the stock piping, now he is going for 600kw. I will let you know how he goes.

After seeing 350kw through 2.25 inch piping, 80mm should therefore easily flow 600 by my books. Just letting you know as most workshops would have upgraded it at much less power. The more you compress the air the smaller the pipes need to be, that much is obvious yeh?

It will work, but it won't be efficient. Pressure drop through the pipe work alone might be 10psi at a random guess at high flows.

Assuming constant flow, the smaller the pipe will produce an increase in pressure.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Latest Posts

    • Hi, is the HKS  Tower Bar still available ? negotiable ? 🤔
    • From there, it is really just test and assemble. Plug the adapter cables from the unit into the back of the screen, then the other side to the car harness. Don't forget all the other plugs too! Run the cables behind the unit and screw it back into place (4 screws) and you should now have 3 cables to run from the top screen to the android unit. I ran them along the DS of the other AV units in the gap between their backets and the console, and used some corrugated tubing on the sharp edges of the bracket so the wires were safe. Plug the centre console and lower screen in temporarily and turn the car to ACC, the AV should fire up as normal. Hold the back button for 3 sec and Android should appear on the top screen. You need to set the input to Aux for audio (more on that later). I put the unit under the AC duct in the centre console, with the wifi antenna on top of the AC duct near the shifter, the bluetooth antenna on the AC duct under the centre console The GPS unit on top of the DS to AC duct; they all seem to work OK there are are out of the way. Neat cable routing is a pain. For the drive recorder I mounted it near the rear view mirror and run the cable in the headlining, across the a pillar and then down the inside of the a pillar seal to the DS lower dash. From there it goes across and to one USB input for the unit. The second USB input is attached to the ECUtec OBD dongle and the 3rd goes to the USB bulkhead connected I added in the centre console. This is how the centre console looks "tidied" up Note I didn't install the provided speaker, didn't use the 2.5mm IPod in line or the piggyback loom for the Ipod or change any DIP switches; they seem to only be required if you need to use the Ipod input rather than the AUX input. That's it, install done, I'll follow up with a separate post on how the unit works, but in summary it retains all factory functions and inputs (so I still use my phone to the car for calls), reverse still works like factory etc.
    • Place the new daughterboard in the case and mount it using the 3 small black rivets provided, and reconnect the 3 factory ribbon cables to the new board Then, use the 3 piggyback cables from the daughterboard into the factory board on top (there are stand offs in the case to keep them apart. and remember to reconnect the antenna and rear cover fan wires. 1 screw to hold the motherboard in place. Before closing the case, make a hole in the sticker covering a hole in the case and run the cable for the android unit into the plug there. The video forgot this step, so did I, so will you probably. Then redo the 4 screws on back, 2 each top and bottom, 3 each side and put the 2 brackets back on.....all ready to go and not that tricky really.      
    • Onto the android unit. You need to remove the top screen because there is a daughterboard to put inside the case. Each side vent pops out from clips; start at the bottom and carefully remove upwards (use a trim remover tool to avoid breaking anything). Then the lower screen and controls come out, 4 screws, a couple of clips (including 3 flimsy ones at the top) and 3 plugs on the rear. Then the upper screen, 4 screws and a bunch of plugs and she is out. From there, remove the mounting brackets (2 screws each), 4 screws on the rear, 2 screws top and bottom and 3 screws holding in the small plates on each side. When you remove the back cover (tight fit), watch out for the power cable for the fan, I removed it so I could put the back aside. The mainboard is held in by 1 screw in the middle, 1 aerial at the top and 3 ribbon cables. If you've ever done any laptop stuff the ribbon cables are OK to work with, just pop up the retainer and they slide out. If you are not familiar just grab a 12 year old from an iphone factory, they will know how it works The case should now look like this:
    • Switching the console was tricky. First there were 6 screws to remove, and also the little adapter loom and its screws had to come out. Also don't forget to remove the 2 screws holding the central locking receiver. Then there are 4 clips on either side....these were very tight in this case and needed careful persuading with a long flat screw driver....some force required but not enough to break them...this was probably the fiddliest part of the whole job. In my case I needed both the wiring loom and the central locking receiver module to swap across to the new one. That was it for the console, so "assembly is the reverse of disassembly"
×
×
  • Create New...