Jump to content
SAU Community

Recommended Posts

Just now, Birds said:

Power is directly related to torque, son. These engines aren't different enough that if producing the same power there will be a large difference in peak torque. You'd be talking ~50nm at best. The 25 will bring on the torque and power earlier and that's about it. Hardly cog-stripping material. Unless he's button clutching it with a locker and slicks he'll be right.



Tell that to a 7L V8 in an old ute that only makes 200kw but can tow a GTR on a trailer behind it without breaking a sweat. 

RB20s are junk, and their gearboxes are even bigger junk. There is a large difference in low down torque, stop looking at dyno sheets for proof and go test drive the engines back to back. How many people have you seen say that they need to ring a 20's neck above 5k to get it moving. Considering you have a high flow and brag about its response.. I don't think you could live with a 20 even though its "only ~50nm at best" 

If you're gonna convert it to 25, which you won't because you've already made up your mind, buy the box... otherwise whatever.

Completely different engine. Let's keep the comparisons sensible shall we...given we're talking about two engines that, all things equal, are 500cc different. That is why I'm happy to generalise that, with similar power levels, one won't be smashing cogs over the other.

FYI...I have driven RB20s and RB25s, back to back. I agree the former is a piece of shit that takes forever to make power, but this fact is largely irrelevant, because when it does make that power it is nearly the same peak torque being transferred through the gearbox. Load and peak torque are what smashes gears, not where in the rev range that peak is...which is ultimately the difference between a 20 and a 25.

And if we're going down the path of experience...well...I've fitted countless 20DET gearboxes to modified vehicles, from VLs and 31s to S15s and 25DE+Ts. Done a lot of 25DET gearboxes too. It is the far superior gearbox, but as long as you're not smashing synchros and dumping button clutches with slicks, you're unlikely to break the 20DET box with less than 250rwkw in a 25.

Anyway, I can't see Pat putting in a 25, as he doesn't want to overcapitalise on a 5k(?) car. Hence the garden variety detailing jobs.

  • Like 1

Quick question for the IT dudes in here. Revolution IT did the load testing on the Census website and ran it at 150% of the expected users to login at the same time. They charged the government $500,000 to run these tests. Does that seem exorbitant? I can imagine they'd have a powerhouse of a computer and server system but god damn that's a lot of money for something that still failed anyway...

well they failed so yes exorbitant.

 

to load test something that they expect 10 million hits in a couple hours...well you have to replicate millions of users, honestly to do it properly I would expect it to be more.

 

 

 

Completely different engine. Let's keep the comparisons sensible shall we...given we're talking about two engines that, all things equal, are 500cc different. That is why I'm happy to generalise that, with similar power levels, one won't be smashing cogs over the other.

FYI...I have driven RB20s and RB25s, back to back. I agree the former is a piece of shit that takes forever to make power, but this fact is largely irrelevant, because when it does make that power it is nearly the same peak torque being transferred through the gearbox. Load and peak torque are what smashes gears, not where in the rev range that peak is...which is ultimately the difference between a 20 and a 25.

And if we're going down the path of experience...well...I've fitted countless 20DET gearboxes to modified vehicles, from VLs and 31s to S15s and 25DE+Ts. Done a lot of 25DET gearboxes too. It is the far superior gearbox, but as long as you're not smashing synchros and dumping button clutches with slicks, you're unlikely to break the 20DET box with less than 250rwkw in a 25.

Anyway, I can't see Pat putting in a 25, as he doesn't want to overcapitalise on a 5k(?) car. Hence the garden variety detailing jobs.



I agree with everything in this post

I was tempted to see what would happen if deliberately inducing lag by ramping boost late (like a centrifugal charger) would be a way to get 400+kw from a R33GTST box.

Would be interesting to see what the torque curve would be like if you run say 14psi at 4k then ramp it slowly to 25psi at 7k. May be a way of keeping a box going. Should result in a big flat line for torque as opposed to a massive spike then it falling off.

12 hours ago, emts said:

well they failed so yes exorbitant.

 

to load test something that they expect 10 million hits in a couple hours...well you have to replicate millions of users, honestly to do it properly I would expect it to be more.

 

 

 

Pretty much this.. I'm not in the webhosting business so can't explain HOW they'd actually test millions of users at the same time accessing their server(s) I'd guess they'd have a bunch then just use math to multiply the load up to however many users.. 

Lets not forget the failure could be due to hackers etc attacking 'for the lulz'

And also that there's a lot more underlying than just server load.. you've got to have enough network infrastructure and bandwidth to flow all that traffic which I reckon is where it would have failed. Like the Monash. 

Don;t call these guys Hackers, thats giving them way too much credit, it is script kiddies doing a Ddos via a zombie network. (if it was an attack)

 

It's that easy even Birds could do it.

http://www.symantec.com/connect/blogs/renting-zombie-farm-botnets-and-hacker-economy

 

the funny thing is load testing is a very similar process, get a whole bunch of boxes and start loading/posting data to the site. monitor.

 

What is interesting is that this might not actually be a DDos attack just a crappy scoping exercise.

so apparently they estimates the traffic at max 1 million users per hour, so the load testing at 150% would be 1.5 million users.
now lets say there around 10 million users submitting online.
I would guess around 1/2 would have sat down in the evening and gone ok Fk it lets do it.
so 5 million in 2ish hours or much more than they scoped.

they could have Ddosed themselves with legit traffic.

 

that also said doing it in the "cloud" is meant to mitigate this as they can just virtually throw more CPU's at it till traffic is gone. 

 

 

 

3 hours ago, Kinkstaah said:

I was tempted to see what would happen if deliberately inducing lag by ramping boost late (like a centrifugal charger) would be a way to get 400+kw from a R33GTST box.

Would be interesting to see what the torque curve would be like if you run say 14psi at 4k then ramp it slowly to 25psi at 7k. May be a way of keeping a box going. Should result in a big flat line for torque as opposed to a massive spike then it falling off.

Keeping all the bad parts of a turbo and getting rid of the good is a Mohsen spec idea.

Might as well fit a smaller turbo that will deliver the same boost and power much earlier on. The reason you'd be getting 400rwkw from the box is that the engine is seldom going anywhere near that and you've effectively dulled your turbo to perform like a small one, but with more lag. If the box can't handle 400rwkw, the day you take it to that peak is likely the day it will break. Unless the box weakness is its input shaft, 4th gear being a 1:1 is less likely to strip cogs.

Think of it this way - a chair is rated to seat 100kg. Someone 140kg sits down on it, quick or fast, that chair is eventually going to break under their weight. You can break it with 80kg if you jump on it (ala dumping clutch).

A turbo ramping up fast isn't quick enough to snap teeth; only the torque limit of the box or a sudden surge from standstill will do that.

2 hours ago, UNR33L said:

Pretty much this.. I'm not in the webhosting business so can't explain HOW they'd actually test millions of users at the same time accessing their server(s) I'd guess they'd have a bunch then just use math to multiply the load up to however many users.. 

Lets not forget the failure could be due to hackers etc attacking 'for the lulz'

And also that there's a lot more underlying than just server load.. you've got to have enough network infrastructure and bandwidth to flow all that traffic which I reckon is where it would have failed. Like the Monash. 

Oh I forgot to...carry the 1

tumblr_lkhcjft2j91qztjn5o1_500.png

  • Like 1
16 minutes ago, Birds said:

Keeping all the bad parts of a turbo and getting rid of the good is a Mohsen spec idea.

Might as well fit a smaller turbo that will deliver the same boost and power much earlier on. The reason you'd be getting 400rwkw from the box is that the engine is seldom going anywhere near that and you've effectively dulled your turbo to perform like a small one, but with more lag. If the box can't handle 400rwkw, the day you take it to that peak is likely the day it will break. Unless the box weakness is its input shaft, 4th gear being a 1:1 is less likely to strip cogs.

Think of it this way - a chair is rated to seat 100kg. Someone 140kg sits down on it, quick or fast, that chair is eventually going to break under their weight. You can break it with 80kg if you jump on it (ala dumping clutch).

A turbo ramping up fast isn't quick enough to snap teeth; only the torque limit of the box or a sudden surge from standstill will do that.

That's the thing though, most dynos have *peak* torque at ... I dunno, 4k? Usually when the car hits full boost, middle of the range.

If you backed power off in that range, your torque would not look like that. Instead of being 620nm at 4k then bleeding off to 500, you could have it peak at 500 and stay at 500 the whole way through the rev range.

Look at most people's dyno sheets, the max power figure is not where the most torque is.

At least in my car having huge power at 4k only rips tyres anyway. I'd probably result in a car which is faster through being easy to drive, and won't smash gearboxes. I am aware that losing traction means driveline stress wouldn't happen anywhere near as bad, but usually 33 boxes die from stripping gears. Under load. Usually 3rd. Usually when cars are on full boost/torque and not losing traction anymore.

 

So my idea was simply to spread that out over the rev range instead of having it all come in hardcore when the turbo spools up.
Going a smaller turbo isn't an option for me, my car has the tendency to choke the living shit out of anything smaller than a GTX3582R. I had to run a GTX3076r with a limit of 5700rpm to avoid the car melting itself.

 

Ideally you'd just have a gearbox that can handle the torque. But rarely do we get exactly what we want in modding cars :P

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

    • Must have been an absolute nightmare to drive when the power steer was out, the rack ratio/wheel size/caster is all set up for power assistance
    • Welcome to SAU, what are you looking at buying?
    • I checked the injectors again (1 and 2, since they’re easiest to access) to make sure they weren’t clogged. Even though the entire fuel system had been cleaned, I wanted to be certain. Everything looked clean, so I reinstalled and connected everything. When I started the car to confirm everything was okay, it immediately revved up high, so I shut it off straight away. I checked to see if I’d missed a vacuum hose or something, but everything was connected. On the second attempt, the car ran without the high idle, but I noticed a distinct “compressed air” sound coming from the engine bay. Tracing the sound, I pushed injector #6 forward slightly and the noise stopped — it turned out it wasn’t seated properly, despite the fuel rail being bolted down. While holding it in place, the car idled steadily without stalling and ran for over 5 minutes. At this point, I pulled all six injectors out just in case I hadn’t seated them correctly or dirt had gotten onto the O-rings. Unfortunately, I discovered that I had damaged 3 out of 6 injectors (the OEM 270cc ones) during installation. So yes, this was my fault. Since only the pintle caps were damaged, I’ve ordered a Fuel Injector Service Kit from NZEFI to refurbish them. In the meantime, I reinstalled my new injectors – the car now idles fine for over 15 minutes without stalling. I have not attempted to drive it so far. It’s not perfect yet, as it hesitates when the throttle is pressed, but it’s a big improvement. Unplugging the IACV with the new injectors idles at around 800rpm, even with the IACV screw tightened fully. But this is probably due to tune.
    • I wanted to try and preserve the front bumper as long as possible, they're not cheap and are made to order in Japan. Taking inspiration from my previous K11 Micra build where I made an undertray for the Impul bumper, I did the same for this BN Sports bumper but a little slimmed down.  This time round I only made a 'skid plate' (if that's the correct wording/term) for just the bumper surface area, the Micra version covered the gap like an undertray. Starting off with a sheet of mild steel approx. 0.9mm thick 4ft x 2ft in size. I traced around the bumper, cut it out and cleaned the edges. Luckily I was able to get two halves from one piece of metal In the video I installed it as is, but I've since then I've removed it to spray and add a rubber edging trim. The rubber trim is suitable for 1-2mm and it's a really nice tight fit. The bolts had to be loosened due to the plates being too tight against the bumper, the trim wouldn't push on I used some stainless M6 flat headed bolts for a flusher finish (rather than hex heads poking down), I believe this style fastener is used for furniture too incase you struggle to source some. The corner's are a little wider, but this may be an advantage incase I get close to bumping it  The front grill got some attention, finally getting round to repairing it. Upon removal one fixing pulled itself out of the plastic frame, one side is M8 that fixes inside of the frame, where as the other side is M5. Not knowing I could get replacements, I cut down an M8 bolt, threaded it inside the frame along with a decent amount of JB Weld.  The mesh was replaced to match the bumper. One hole on the bonnet/hood had to be drilled out to 8mm to accommodate the new stud, once the glue had set it could be refitted. I think the reason the grill was double meshed was to hide the horn/bonnet latch (which makes sense) but I much prefer it matching the bumper Bumper refitted and it's looking much better IMO The Youtube video can be seen here: https://www.youtube.com/watch?v=bVZP35io9MA
    • The video for the servicing and fuel filter change can be seen here: https://www.youtube.com/watch?v=uLJ65pmQt44 One of the main jobs I wanted to do before the car officially went on the road, was to remove the awful looking blue silicone hoses. There's nothing wrong with having coloured silicone hoses, but I realise as I'm getting older I prefer monotone engine bays with a splash of colour on the engine cover(s). I cover this in a lot more detail in the Youtube video, so unfortunately there's limited photos of the process. The intercooler, upper radiator, boost vacuum and upper breather hoses were all changed to black silicone with mikalor clamps. The only blue left is a blanking cap at the back of the inlet manifold and the GReddy pulleys (which will be replaced for stock when the cambelt gets replaced) While the intercooler pipes were off I gave them a quick clean/polish too A before photo I do have a replacement air filter on its way. Fuse box covers were painted blue, they're now satin black Another job on the list while the bumper was off, is to add some mesh https://live.staticflickr.com/65535/54737966256_99b28bfa30_c.jpg[/img] I was hoping to use some thin wire to secure it, but it seems I've misplaced it and the wire I had was too thick to twist easily. I ended up using cable ties for the time being https://live.staticflickr.com/65535/54737131882_c2b7989dcc_c.jpg[/img] Was pleasant to see this https://live.staticflickr.com/65535/54737131627_8b2aab13b3_c.jpg[/img] The last thing to do was to fix the front grill and re-mesh that to match but I ran out of time The Youtube video can be seen here: https://www.youtube.com/watch?v=R4FsF6tgizE&t=23s
×
×
  • Create New...