Jump to content
SAU Community

Atr43ss-2 Prototype Initial Tune 250rwkws 18psi<2500rpm, Stupidly Responsive


Recommended Posts

All this talk of RPM vs load vs PSI is making me dizzy.

Here's one for the tuners out there with a dyno.

Strap a car car down and do a full power run through all the gears and post the results. I'd like to see power, torque and manifold pressure. It would help to paint a clearer picture of how a turbo car makes power in relation to boost, RPM and load.

Anyone willing and able?

EDIT: Im happy to donate my car for a few hours if required too - r33 GTST with FMIC, exhaust and pod - everything else stock.

Link to comment
Share on other sites

  • Replies 118
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Posted Images

All this talk of RPM vs load vs PSI is making me dizzy.

Here's one for the tuners out there with a dyno.

Strap a car car down and do a full power run through all the gears and post the results. I'd like to see power, torque and manifold pressure. It would help to paint a clearer picture of how a turbo car makes power in relation to boost, RPM and load.

Anyone willing and able?

EDIT: Im happy to donate my car for a few hours if required too - r33 GTST with FMIC, exhaust and pod - everything else stock.

Come on, someone do it!

Link to comment
Share on other sites

STAO - how would a pair of these go in a RB26dett? bolt-on.. possible? thoughts?

cheers

Naa they will be way too laggy to run as twin on a RB26det (1.3L / Turbo vs 2.5L / Turbo). We can high flow them with 2860RS cores. will deliver better result.

Link to comment
Share on other sites

Naa they will be way too laggy to run as twin on a RB26det (1.3L / Turbo vs 2.5L / Turbo). We can high flow them with 2860RS cores. will delivery better result.

Wouldn't that be the same as buying a 2860-9 or similar?

Or are the results different?

Apologies for hijacking the thread.

Link to comment
Share on other sites

Wouldn't that be the same as buying a 2860-9 or similar?

Or are the results different?

Apologies for hijacking the thread.

RS has different turbine wheel. Probably not much more in HP, but lot more torque. We've been using those 2x types of CHRAs in our 300zx turbo developments. Very noticeable amount of difference on road, The RS gives stronger pulling sensation while both turbos made within 2KWs difference.

Link to comment
Share on other sites

You will have to try the dual port actuator out for yourself.

I haven't personally used one, but my brother did on his Gt3040 turbo.

Sadly in his case it didn't work and he had to use a 1.5 bar standard style actuator to

get the 26psi he wanted.

turbo looks interesting, be good for a auto stagea maybe

cheers

darren

Link to comment
Share on other sites

You will have to try the dual port actuator out for yourself.

I haven't personally used one, but my brother did on his Gt3040 turbo.

Sadly in his case it didn't work and he had to use a 1.5 bar standard style actuator to

get the 26psi he wanted.

turbo looks interesting, be good for a auto stagea maybe

cheers

darren

I wouldn't thought this theory works as my actuator's spring pressure is already greater then intake manifold pressure. Obviously actuator's rod force is not based on the sum of both pressures, but only the strongest.

Based on the physics of: force = Pressure x Area

I've trailed it by reducing the "Area" which is the wastegate port size. This has worked. boost is holding at 18psi perfectly, I’ve also engineered it as adjustable suiting larger sized engines. I will find out the effects it has based on the end results next week..

How ever this is still not my main goal of stabilizing exhaust manifold pressure.

So I've made a rough model of have an external wastegate integrated into an internal gated setup.

1.jpg

2.jpg

3.jpg

4.jpg

If this works as expected it will be able to keep the top end steady while picking up another 10~15KWs. I'm not sure if this is counted as "Road legal" assuming this is some how internally wastegate.

Link to comment
Share on other sites

RS has different turbine wheel. Probably not much more in HP, but lot more torque. We've been using those 2x types of CHRAs in our 300zx turbo developments. Very noticeable amount of difference on road, The RS gives stronger pulling sensation while both turbos made within 2KWs difference.

Interesting, might be in touch once I save up some money...which could take quite a while :)

Link to comment
Share on other sites

i dont see the point of a ghetto external gate onto an internal gate turbo

isnt the point of an external gate setup

so that all of the flow/prssure on the exhaust side runs through the entire housing snail to give the best possible flow/veloicity and drive the compressor harder/quicker and when target is reached, the external gate releases back pressure to control flow.

vs internal gate

all of that flow/pressure runs through the smaller exhaust housing as it has to account for internal wastegate bypass

it's a reasonable expectation that an external gate setup always comes on boost quicker and has better response

but its also resonable to expect more cost involved

i see no value or gain in control of boost etc in an internal to external ghetto mod

Link to comment
Share on other sites

The Pressure is dumped out of the turbine housing and plumbed back into the exhaust side. Its not re-circulating back into the snail. Same setup as plumb back external gate.

Its a prototype model, We'll find out if it works or not soon. :)

Link to comment
Share on other sites

im sure it will work, although turbulence might become an issue... i always regarded the exit point of the turbo as crucial, no expert here tho

Link to comment
Share on other sites

The Pressure is dumped out of the turbine housing and plumbed back into the exhaust side. Its not re-circulating back into the snail. Same setup as plumb back external gate.

Its a prototype model, We'll find out if it works or not soon. :banana:

So the internal gate is just sitting there? Not dissing your design at all just wondering; promising looking turbo.

I'm not too sure if the gate will work or is the best solution since I don't see how much different from an internal waste gate plumbing back like that other than the fact the external waste gate can probably accommodate for larger volume of gas but AFAIK it really shouldn't be necessary at this power range. And even then, you're just putting the gas back into the turbo housing again anyway? (correct me if wrong)

I think it's that the exhaust housing is too small to accommodate for the engine at the higher revs and boost in the current situation and therefore it chokes at the turbine side of the turbo. If you want to keep the responsiveness (which I definitely would like to see) then increasing the size of the rear housing is out of the question or really makes things much more complicated at least. Though, have you thought of methods of moving the air out of the turbo faster?

I mean, could it be as simple as a better front/dump pipe, cat, exhaust?

Dyno running with no dump pipe/front pipe just to test can confirm/disprove my hypothesis.

To add to the discussion regarding boost/power in earlier gears in the previous pages of this thread. My understanding is that an engine will suck up an amount of air equal to:

V_air / minute ~= Displacement x RPM x Absolute pressure

And proportionately an amount of exhaust fumes is produced. So no matter what gear you're in the turbo will behave the same.

It is true that a turbo might not be able to spool up fast enough in the lower gears though.

Also, from my understanding, gears ratio's smaller than 1:1 (engine:gear) you're multiplying the amount of torque (rotational acceleration) at the wheels.

This is why they dyno your car in fourth gear (1:1). So you can comfortably say when you have 200kw ATW, you have 200kw's + unknown amount of power lost due efficiencies at the engine. Without having to do a chunk of maths.

i.e.

ATW_Power = Flywheel_Power - (Work / sec)

Work in this case is the drive train.

What all that means is that it doesn't matter what gear you're in when it comes to the performance of the engine and consequently turbo.

My 1c

Link to comment
Share on other sites

  • 4 weeks later...
  • 2 weeks later...

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
 Share




  • Latest Posts

    • Unless there's something particular about the Greddy manifold's injector holes that I'm not aware of, those injetcors look to be totally wrong. They would absolutely want to be spaced up to get those long snouts out of the runner. Which, I think, is not usually the way that that problem is solved. I think the problem is solved by using the correct injectors, which would be much more like what Andrew posted.
    • Thanks for the reply, So i've continued playing around, and fitted the injector adaptors onto the injector, the fuel rail is not able to be mounted now as the injectors sit a bit further out. I suppose the point of the adaptors is so that the injector nozzle isn't so deep into the intake? I suppose 1mm extra on the o-ring would do it but still can't mount the rail onto the intake haha. Waiting on a reply from Aeroflow I'm sure there's something stupid that I'm missing...
    • EMJ33 or EJM33 - west end
    • I have a radium fuel rail on my Greddy manifold and used the supplied radium fuel injector to manifold adapters (The round green things pictured). I did always wonder if you could just go ahead and use the second lower hole like you're doing... Wouldn't thicker o-rings solve your issue?    
    • From what I've seen and experienced first hand with those powder extinguishers, they're good to use to break a window and escape the car, and half the time then do f**k all to stop a fire. You just need much more than 1KG worth of powder. Not to mention, half the time it's an engine bay fire, and you can't easily, and do not want to completely open the bonnet, so you're left pretending to be an American Infantry... Spray and Pray baby!   And then 100% that shit is really destructive afterwards!   Realistically, those little ones at a race track might help you keep the fire from growing and give the fire marshal / truck a chance to actually get to you with their multiple large bottles.   For a road car, these days, prepare to deboard as quickly as humanly possible, and move to safety. Allow insurance to fix replace it (unless it's like a rare classic etc, then do nearly everything possible to save it!) Keep the little extinguisher with you to help protect other things around you from burning while you stand there singing "How can we sleep while our beds are burning?"   Secondly, powder extinguishers I freaking hate for indoor use, (this isn't really relevant to a car) as you will get a powder fog around you, and it can be disorientating.   When I did fire training when at BlueScope Steel, they have (had?) their own fire brigade on site. We did all the training, and at the end we were told, "If it's an indoor fire, and you need to use a powder extinguisher, we as the fire brigade would rather you just exit the building, you're more likely to get lost in the smoke and powder fog than do much help, so just GTFO" And pretty much that was what they said for most other fires too, grab extinguisher, if it's much more than paper in a bin fire, use extinguisher to get you and others out of the building to safety...   Part of me wishes when my Skyline caught alight many moons ago, I let insurance sort it out, instead of putting the fire out... part of me now says "But I've saved a classic before it was a classic!"
×
×
  • Create New...