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.

  • 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!

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.

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.

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.

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

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.

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 :)

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

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. :)

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

  • 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



  • Latest Posts

    • My dream is also to have a proper hoist, but I don't think it will ever happen. My quickjack is probably as close as I'll ever get, it really is very good though. 
    • Yeah we keep on in the dailies, it is pretty poor how many animals get hit and the driver leaves without checking....have saved a couple of little ones over the years. Bit of a gruesome job though, pouches generally need to be cut open because they are so tight and often the joey doesn't realise mum is gone so they are still locked onto the teat. I checked the modules in front of the DS wheel where an oil cooler should go.... There is the radar unit - that can go for race use) One of the 2 HX water pumps, the silver cylinder. That needs to be kept but might be able to be relocated But the bad news, the big computer mounted vertically in front of the wheel (blocking any potential air exit) is the electric steering computer. That is required until/unless i do a hydraulic steering conversion, and in CAD based modern car design it is not like I can just pop a big unit like that somewhere else (plus the loom would be too short anywhere else too). So, the passenger side is OK to clear out (just use a smaller washer reservoir, potentially elsewhere), but the DS no beuno
    • Well, all the best with the new camry It was interesting to hear about the UK process, it is generally a lot more streamlined here with a shipping agent looking after all the import side (noting the exact final price can still be a surprise.....) and I've used a few different brokers on the japan (or US) side, and never had any trouble with any of them....luck of the draw I guess. You mentioned you didn't get the auction sheet (understandable since you bought it from a dealer, not auction), but I always try and get hold of that because they are pretty thorough. I've imported 2x R grade vehicles over the years and both were fine, repairs in Japan are pretty thorough compared to here in Oz.
    • BTW I measured the jack I have, it is 70mm at the saddle but you only have about 700 until it returns to 150mm high at the cylinder so it is good but no magic bullet.
    • My experience with Rising Sun Exports Before agreeing to the sale I tried to do as much research as I could (obviously), his Facebook reviews are 98% and he goes Live at least once or twice a week. I contacted 2 people in the UK who had used him for their imports, both had positive feedback. His explanation and talk through of the import process was thorough, answering any query no matter how stupid it was. It felt as soon as the money was sent, communication dropped off. I asked for shipping updates every 2 weeks or so, not wanting to pester him, he never had any updates. I wasn't informed the car had been dropped off at the port, I only found out by his Facebook story. I asked for the photos taken at the port, knowing he would need some for insurance purposes. I received a few 5 second clips and that's it. When asked again, he said his staff had them. Weeks later I asked again, he tells me he doesn't have any, but does have 50 photos from the original advert. I never received them. I eventually got the documents sent via WhatsApp after I mentioned the port was requesting them. I purchased a CarVX report, to find out the vehicle is a Grade R with recorded accident damage, first recorded in 2017 when it was first auctioned. He never told me the grade, then again I didn't ask. His response was "Grade R means nothing, it wasn't chassis damage". Still, I would have liked to have been informed about it. Jon prides himself on being open and honest when it comes to inspecting cars, it's his main job doing so at the auctions for customers. When the vehicle arrived in the UK I noticed a few little cosmetic issues. It's a 21 year old car so it wasn't going to be mint condition. The side skirts are cracked on each corner and the sealant is failing. The front grill on the bonnet/hood isn't secured very well, mounting studs are missing. Both minor things, but again, it would have been nice to be told. During a Facebook Live walk around video of the vehicle, he mentioned it has a front Whiteline anti roll bar/sway bar. While on the inspection ramp, I noticed the stock item has been installed. When first questioned, his response was "the ARB? Switched? Since when, it never had them". Since sending video and photo evidence I've not received a response. I'm probably being over critical of the overall condition of an old car, but all I wanted was honesty (which he claims to have). I'm aware I wasn't his only customer, he's busy doing XYZ but other reviews praise him for great communication with regular updates and photos, I felt I didn't receive the same treatment. 
×
×
  • Create New...