Jump to content
SAU Community

Recommended Posts

  • 1 month later...

New result to share. This is an ATR45SAT ball bearing bolton turbo running of an external gate from factory exhaust manifold. Car is an R34 GTT with a freshed up Rb25det NEO engine. Car made 420rwkws @ 25psi of boost E85 fuel, 240rwkws @ 4000RPM, Nice and responsive. 

spacer.png

 

spacer.png

 

 

  • Like 2
  • 2 weeks later...
New result to share. This is an ATR45SAT ball bearing bolton turbo running of an external gate from factory exhaust manifold. Car is an R34 GTT with a freshed up Rb25det NEO engine. Car made 420rwkws @ 25psi of boost E85 fuel, 240rwkws @ 4000RPM, Nice and responsive. 
power.jpg&key=91cf0f95b9a5de09e3b2e49c223b7f9ad46c620075f2242c13768e6310ac984a
 
boost.jpg&key=14d9ac558f5b9d5cbe0f19f7ed5fb73d4d02474e4b18df3990160d2729303606
 
 



Is there a twin scroll housing that would fit this turbine?

I can supply a .84 rear housing in twin scroll. It won't be as responsive. If you have a twin pulse twin gate manifold, you can use the .63 single housing with an ATR45SS-1 to make 450rwkws+ while still have similar response as above. 

I can supply a .84 rear housing in twin scroll. It won't be as responsive. If you have a twin pulse twin gate manifold, you can use the .63 single housing with an ATR45SS-1 to make 450rwkws+ while still have similar response as above. 


Have you tested it with the .84 twin scroll rear on a true twin scroll twin gate manifold?

I would be genuinely surprised if it was less responsive [emoji848]
4 hours ago, LaurelPWR said:

 


Have you tested it with the .84 twin scroll rear on a true twin scroll twin gate manifold?

I would be genuinely surprised if it was less responsive emoji848.png

 

Same thought, a true twin scroll and proper divided setup would be more responsive than a single scroll.

  • Like 1
20 minutes ago, Dose Pipe Sutututu said:

Same thought, a true twin scroll and proper divided setup would be more responsive than a single scroll.

Interesting thing happened around here recently, a guy with a 2litre Subaru running a twin scroll manifold and a open housing .63 GTX3076R decided he was happy with the power he was making but wanted more spool so swapped to a .61a/r divided hotside - using the same exhaust manifold, but changing the up-pipe to suit the twin scroll housing.  The car improved spool by a couple hundred rpm and lost around 50kw @ wheels.

After going through a bunch of diagnostics and deciding there were no other issues or changes other than the housing/flange setup he tried changing to a .83a/r twin scroll housing and it got back within 20kw of the .63 housing, but was also no better spool than with the open housing option.


Again, after further head scratching and messing around he decided to swap back to the original up-pipe and .63a/r housing and boom!  Back to the same power and response he had before trying the divided path.   Definitely not what I would have expected, but it's a thing that happened - unfortunately I am not directly involved so I have no more detail than what I've shared here, I wouldn't count out the possibility there is some other variable at play but realistically the options are pretty minimal... especially when it came back to "full power and response".   The car is definitely performing overall better with the .63 hotside.

  • Like 2
3 minutes ago, Dose Pipe Sutututu said:

Only thing I can think of with the EJ, is the turbo manifold of equal header lengths or is it the usual unequal length business?

The twin scroll turbo manifolds are equal length, which is why a lot of the later Subarus don't sound like 5-cylinder RBs :)

  • Like 2
18 minutes ago, Lithium said:

The twin scroll turbo manifolds are equal length, which is why a lot of the later Subarus don't sound like 5-cylinder RBs :)

Interesting nevertheless, hopefully my selection of parts will work.

Car is coming out of fab work this week.

  • Like 1

Why should twin scroll exhaust manifold and housing make slightly better response. It very dependent on the design of the actual exhaust manifold and of course the firing sequence of the engine. Lets take Rb25det with firing sequence of:

1 5 3 6 2 4

Stock twin pulse log manifold consist bank 1 of: CYC 123, and bank 2 of: 456. 

So the split plus ensures the combusted air shoots straight into turbine housing rather then towards the other side. I've seen customers drilling out the center divider of factory exhaust manifold result in lose of response and power. I'm currently using a merged pulse external gate on a factory exhaust manifold, and by doing that I have lose about 300RPM of response, I think it would partly contributed the this problem and the extra volume external gate plumbing has made up.

Same principle apply to a spaghetti manifolds, but I found its not as tangible as the runners are separated that ends up in a collector. So there will be a bit of a differences assume a properly made twin pulse, twin gated exhaust manifold used on the right size twin pulse turbine housing. 

The advantage of twin gates giving extra flow would mean you can use a smaller housing on a turbo that makes the same top end as a big housing while avoiding the lag. 

 

Edited by hypergear
6 hours ago, hypergear said:

Why should twin scroll exhaust manifold and housing make slightly better response.

So the split plus ensures the combusted air shoots straight into turbine housing rather then towards the other side. I've seen customers drilling out the center divider of factory exhaust manifold result in lose of response and power. I'm currently using a merged pulse external gate on a factory exhaust manifold, and by doing that I have lose about 300RPM of response, I think it would partly contributed the this problem and the extra volume external gate plumbing has made up.

The advantage of twin gates giving extra flow would mean you can use a smaller housing on a turbo that makes the same top end as a big housing while avoiding the lag. 

The theory on split pulse is pretty well discussed these days, reduces the collisions between high pressure pulses and keeps them separate until they are meant to drive the turbine.  I suppose you could say that it should reduce turbulence and as such keep velocity up.

In regards to people removing the divider in the stock manifold, I think of that more like a turning vane than a split pulse - without it there is nothing to make the exhaust flow think that it should just head straight to the other cylinders due the shape angles required to head to the turbine.  I am not sure that has so much relevance in the twin scroll/split pulse discussion, aside from the fact that the only reason that is at all a workable design with a straight 6 is that you have alternating pulses on front and rear three so it makes it less likely to cause bizarre lean outs on certain cylinders.

In terms of the twin gate advantage meaning that a smaller housing can flow like a bigger one, I could be missing something or misinterpreting  - so how do you mean?   

At face value it seems like you are saying that having more gate means you will reduce exhaust manifold pressure, but just having a second gate won't increase the turbine's ability to drive the compressor for a given amount of exhaust gas, so there is no reason for it to open more... the only reason the wastegate would flow more is if the turbine needs less exhaust energy to do it's job.   It's pretty easy to tell where more gate is an advantage, you get boost creep as you aren't relieving enough exhaust gas.   If you relieve more exhaust gas then you lose the energy you need to drive the turbine and you don't hit target boost.  

Apologies if I've misunderstood what you said, keen to hear what you mean or where you are coming from with that one.

Edited by Lithium
  • Like 1

I was referring to stock rb25det manifold.  

The twin gate setup, I found its dependent on  the types and shape of turbine wheel as well as size of housing used. I will conduct some experiments later in the year and upload results.

 

 

Edited by hypergear
  • 3 weeks later...
  • 4 weeks later...

Further development in R33 21U high flowed turbochargers. Latest model made 342rwkws fItted to an unopened R33 Rb25det engine as a bolton turbo with FMIC, 3 inches metal intake pipe, 3.5 inches turbo back exhaust, fuel system and programmable ecu.

front.jpg

342rwkw.jpg

boost.jpg  

 

Further development in R33 21U high flowed turbochargers. Latest model made 342rwkws fItted to an unopened R33 Rb25det engine as a bolton turbo with FMIC, 3 inches metal intake pipe, 3.5 inches turbo back exhaust, fuel system and programmable ecu.
front.jpg&key=caaeb2150ace5ab8b3b06e4e35294e2ad8ab539f439990224ac44dee9dfd5c88
342rwkw.jpg&key=0efdb1717652166f679d618c0fcb8f80aeb601c16903e7615b2e875fb27482d8
boost.jpg&key=55370b7ecdcc31a1415905d79e1348c58ce331d99f09daca69f585907f58ec6c  
 



I’m guessing that’s on e85?
Have you done many test with 98ron?
6 hours ago, hypergear said:

Yes that is on E85. I don't have result of this version on 98 yet. it would be sitting pretty close to 300rwkws on that car. 

by the looks of the graph did the boys at G7 Adelaide do the install in tuning ? if so It looks like ill be giving them a visit! Great stuff Tao!

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



  • Similar Content

  • Latest Posts

    • Thanks, I removed the fuse and the relay from the car and made my own circuit with them to test them with a test bulb.  I will look for the wiring diagram and go from there.
    • Jdm DC2R is also nice for a FF car compared to the regular hatches of the time.
    • Now that the break-in period for both clutch and transmission is nearly over I'd like to give some tips before I forget about everything that happened, also for anyone searching up how to do this job in the future: You will need at least 6 ton jack stands at full extension. I would go as far as to say maybe consider 12 ton jack stands because the height of the transmission + the Harbor Freight hydraulic platform-style transmission jack was enough that it was an absolute PITA getting the transmission out from under the car and back in. The top edge of the bellhousing wants to contact the subframe and oil pan and if you're doing this on the floor forget about trying to lift this transmission off the ground and onto a transmission jack from under the car. Also do not try to use a scissor jack transmission lift. You have to rotate the damn thing in-place on the transmission jack which is hard enough with an adjustable platform and a transmission cradle that will mostly keep the transmission from rolling off the jack but on a scissor lift with a tiny non-adjustable platform? Forget it. Use penetrating oil on the driveshaft bolts. I highly recommend getting a thin 6 point combination (box end + open end) wrench for both the rear driveshaft and front driveshaft and a wrench extension. These bolts are on tight with very little space to work with and those two things together made a massive difference. Even a high torque impact wrench is just the wrong tool for the job here and didn't do what I needed it to do. If your starter bolts aren't seized in place for whatever reason you can in fact snake in a 3/8 inch ratchet + 6 point standard chrome socket up in there and "just" remove the bolts for the starter. Or at least I could. It is entirely by feel, you can barely fit it in, you can barely turn the stupid ratchet, but it is possible. Pull the front pipe/downpipe before you attempt to remove the transmission. In theory you don't have to, in practice just do it.  When pulling the transmission on the way out you don't have to undo all the bolts holding the rear driveshaft to the chassis like the center support bearing and the rear tunnel reinforcement bar but putting the transmission back in I highly recommend doing this because it will let you raise the transmission without constantly dealing with the driveshaft interfering in one way or another. I undid the bottom of the engine mount but I honestly don't know that it helped anything. If you do this make sure you put a towel on the back of the valve cover to keep the engine from smashing all the pipes on the firewall. Once the transmission has been pulled back far enough to clear the dowels you need to twist it in place clockwise if you're sitting behind the transmission. This will rotate the starter down towards the ground. The starter bump seems like it might clear if you twist the transmission the other way but it definitely won't. I have scraped the shit out of my transmission tunnel trying so learn from my mistake. You will need a center punch and an appropriate size drill bit and screw to pull the rear main seal. Then use vice grips and preferably a slide hammer attachment for those vice grips to yank the seal out. Do not let the drill or screw contact any part of the crank and clean the engine carefully after removing the seal to avoid getting metal fragments into the engine. I used a Slide Hammer and Bearing Puller Set, 5 Piece from Harbor Freight to pull the old pilot bearing. The "wet paper towel" trick sucked and just got dirty clutch water everywhere. Buy the tool or borrow it from a friend and save yourself the pain. It comes right out. Mine was very worn compared to the new one and it was starting to show cracks. Soak it in engine oil for a day in case yours has lost all of the oil to the plastic bag it comes in. You may be tempted to get the Nismo aftermarket pilot bearing but local mechanics have told me that they fail prematurely and if they do fail they do far more damage than a failed OEM pilot bushing. I mentioned this before but the Super Coppermix Twin clutch friction disks are in fact directional. The subtle coning of the fingers in both cases should be facing towards the center of the hub. So the coning on the rearmost disk closest to the pressure plate should go towards the engine, and the one closest to the flywheel should be flipped the other way. Otherwise when you torque down the pressure plate it will be warped and if you attempt to drive it like this it will make a very nasty grinding noise. Also, there is in fact an orientation to the washers for the pressure plate if you don't want to damage the anodizing. Rounded side of the washer faces the pressure plate. The flat side faces the bolt head. Pulling the transmission from the transfer case you need to be extremely careful with the shift cover plate. This part is discontinued. Try your best to avoid damaging the mating surfaces or breaking the pry points. I used a dead blow rubber hammer after removing the bolts to smack it sideways to slide it off the RTV the previous mechanic applied. I recommend using gasket dressing on the OEM paper gasket to try and keep the ATF from leaking out of that surface which seems to be a perpetual problem. Undoing the shifter rod end is an absolute PITA. Get a set of roll pin punches. Those are mandatory for this. Also I strongly, strongly recommend getting a palm nailer that will fit your roll pin punch. Also, put a clean (emphasis on clean) towel wrapped around the back end of the roll pin to keep it from shooting into the transfer case so you can spend a good hour or two with a magnet on a stick getting it out. Do not damage the shifter rod end either because those are discontinued as well. Do not use aftermarket flywheel bolts. Or if you do, make sure they are exactly the same dimensions as OEM before you go to install them. I have seen people mention that they got the wrong bolts and it meant having to do the job again. High torque impact wrench makes removal easy. I used some combination of a pry bar and flathead screwdriver to keep the flywheel from turning but consider just buying a proper flywheel lock instead. Just buy the OS Giken clutch alignment tool from RHDJapan. I hated the plastic alignment tool and you will never be confident this thing will work as intended. Don't forget to install the Nismo provided clutch fork boot. Otherwise it will make unearthly noises when you press the clutch pedal as it says on the little installation sheet in Japanese. Also, on both initial disassembly and assembly you must follow torque sequence for the pressure plate bolts. For some reason the Nismo directions tell you to put in the smaller 3 bolts last. I would not do this. Fully insert and thread those bolts to the end first, then tighten the other larger pressure plate bolts according to torque sequence. Then at the end you can also torque these 3 smaller bolts. Doing it the other way can cause these bolts to bind and the whole thing won't fit as it should. Hope this helps someone out there.
×
×
  • Create New...