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

[Cowboy1600]

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.

[Tangles]

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

cheers

[Cowboy1600]

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!

[hypergear]

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.

[some_cs_student]

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.

[hypergear]

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.

[jet_r31]

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

[GTScotT]

im curious to see one of these on an rb20

[hypergear]

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.

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.

[some_cs_student]

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

[PM-R33]

Well that is definetely different

[paulr33]

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

[hypergear]

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.

[GTScotT]

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

[Just_Rb]

would this setup have any clearance issues for models with abs systems?

[HtwCHACtkh]

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.

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

[shibby69]

i have an rb 20. i want one!!

how much will 1 of these bad boys set u back.

will it still be stupidly responsive on a 20?

[buzzboy]

any more updates?

[hypergear]

Nope. Unless Variable A/R turbine housing is made to work, this turbo is too small for a RB engine.