Jump to content
SAU Community

Hypergear Turbochargers and High flow Services Development thread


Recommended Posts

I was a little worried it might have RB25 pistons, not RB25neo, but he tells me he ordered them from CP himself directly. Still, it seems to be the most likely cause to me, if all else fails.

The compression test came up 175 across the board which seems normal, but no.3 plug was definitely a different color, looked a little oily.

If it was just high compression the ethanol would have helped more I would have thought. Something is definitely up with it, knocking at 10 degrees isn't normal, unless you are turbocharging a KIA. :P

Link to comment
Share on other sites

hahahahaha. No man. KIA's taking 15 degrees happily.

Well RB25det pistons are lower in compression to Neo pistons any way. Should have helped in knocking prevention. hopefully the engine is all good.

Link to comment
Share on other sites

That's not how it works from what I have read, the neo head has a completely different combustion shape and will bump the compression sky high apparently.

The engine seems strong, and the torque graph was shooting skyward at an insane rate when I left, hopefully it's sorted soon before he burns the car. :P

Link to comment
Share on other sites

No it works the other way around , Neo 25Ts have a lower flatter piston crown to maintain the same 9.0:1 static CR with a smaller volume combustion chamber .

The R33 25Ts have a higher raised piston to get static 9.0:1 with a larger volume chamber .

So in theory if you put a Neo head on a 33 engine the CR is higher than a std 33 . Stick a 33 head on a Neo short block and the CR is lower than a std Neo .

Smaller chamber + flatter piston is the better std system , less chamber surface area to absorb combustion heat and 4 valve engines breathe better with flatter pistons .

If you remember high comp pistons in hemispherical (Hemi) chamber engines you know about the great chunk of piston partially obstructing flow between the valves , it has to be this way because the chamber volume is so big .

Aside from more valve area without big heavy valves part of the pent roof 4 valve chambers advantage is compact chambers so you can get CRs up without high piston crowns .

I'd be comparing the pic of that piston with pics of std 33 and Neo pistons .

A .

Link to comment
Share on other sites

Can confirm - RB25/26 Pistons will result in a HIGH compression ratio on a neo.

Source: my rb29 stroker kit with compatible pistons. (they aren't)

Also good to see the results of the ATR, given I was going to try something almost identical, (or a SS4-5 compressor) and 30psi.

If my car stops exploding.

Link to comment
Share on other sites

I'd be comparing the pic of that piston with pics of std 33 and Neo pistons .

A .

That's what I was led to believe, so 33 pistons in a 34 neo would raise the compression by a substantial amount I would guess...

*Goes to Google image search. :P

Definately a Neo Piston.

This is a Neo piston from my old stock engine

1620354_793268280687533_1972113988_n.jpg

Stock Rb25det piston from google

PIC01403.jpg

Link to comment
Share on other sites

Isn't everyone over east? :P

Stao only uses one casting of .82 internal gate housing for skylines as far as I know, I have asked him for an external housing a few times but it would obviously blow the cost out, as he is tooled up to cnc the internal. I can weld a gate to the housing easily as I have a jig and know where the gate will clear. You would need to organise your own screamer/plumb back pipe locally.

I have to jig up a stock manifold for a suitable gate position still, so I can't really make one until I have an rb25 on the hoist, and a spare manifold. I was hoping to get over to Stao's to check his out, but he is the other side of the city, and we are both too busy atm. Hopefully I could sell it as a kit eventually with the gate and screamer pipe, but is there much of a demand for this setup? I would need to set up a cash back on return system for the old stock manifolds.

Welding off the housing would be best for shipping purposes obviously, and there are so many cheap options out there for housings now, like the stainless Vband Tial copies I use on my car, which make turbo/exhaust swaps so easy compared to the 6 bolt Nissan.

Why u make so hard to choose!

I may just need to go of the housing for now then if its to involved atm to get done on the Stock manifold.

I personally want it because ill be keeping Low mount on my car and dont want the bling of top mount.

Could the below be done if Gate on manifold is to hard.

If i send the turbo to Stao to upgrade to SS2 and he can send to you, you can then put Gate on housing and weld internal.

( Stao can keep internal actuator as a present? )

On a crappy tight schedule aswell because of racewars :(

But i do still have till about 30th March.

Link to comment
Share on other sites

Yes Jarod, PM me about it if you like. We have done that recently and it worked quickly, other than shipping times... it isn't much work for me. He likes to check them after welding I think, just to make sure, but the last one was fine I assume Stao?

I would also need the gate, Vband preferably. Do you have a local fabricator that can do the screamer?

Link to comment
Share on other sites

Yes Jarod, PM me about it if you like. We have done that recently and it worked quickly, other than shipping times... it isn't much work for me. He likes to check them after welding I think, just to make sure, but the last one was fine I assume Stao?

I would also need the gate, Vband preferably. Do you have a local fabricator that can do the screamer?

I'm still waiting from Stao to send me back the housing, I was hoping to fit the turbo up this long weekend and send it to the exhaust shop during the week :(

Link to comment
Share on other sites

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

    • Did a little bit this afternoon and pulled the dump and turbo off so I could take the mani off to clean it up and give it a few coats of paint. Wire wheeled what I could get to and then got the sand paper out to get the tight spots. Gave it one coat so far, will do another two tomorrow and see if I can fit it in the oven to bake it for an hour along with the adapter and dbw.  Hoping the exhaust wrap I ordered turns up soon so I can wrap the dump and screamer. Ordered 30M so I'll wrap back as far as I can to help a little with temp next to the box and also the floorpan. 
    • Yeah I think overall I’m running the expected power I should be running for now and I’ll just enjoy it for the time being until I get some other parts. Thanks for the advice mate I appreciate it!
    • That's fair enough.  Might be time to just enjoy what you have until you sort the ecu/flex sensor situation. You can pretty much guarantee that you are knock limited and e85 is going to be the solution to more power. 
    • He didn’t provide that info to me but I think I’m on standard timing. And no we don’t have e85 on the petrol stations here but it’s widely available here from shops. I’m just planning on getting a better ecu before switching to e85
    • Seems bang on to me , g30-900 will make 900 crank on e85(on paper). Deduct ~25% for 98 and you are at 675 crank. Run that to the wheels and fact you are only running 26psi you end up about your number.  People forget how magic E85 is now that just about everyone is running it.   "Back in the day" you had to be north of 30psi on a 850+hp turbo to get 600 at the wheels on 98.   
×
×
  • Create New...