Jump to content
SAU Community

Recommended Posts

Can't wait to see how a 35 hotside fairs up against a 30 hotside.

What size rear housing is that @hypergear? I've got a 1.01 twin scroll on mine.

Took it out for a squirt this morning and it was running a bit leaner, had to fix up the map. Then started to feed in boost and then it started to misfire lol...

Went home and looked at my logs, nothing out of the ordinary then it occurred to me, I've gone R35 coils lol.. running the stock OEM dwell would definitely be the issue, so pumped in more dwell.

Will be taking the car out tomorrow and seeing how it behaves, fuel is also 6 months old lol.. 

5 hours ago, hypergear said:

Just a quick note, the ATR45SAT you had was a 5 years old unit, current model is different, result has been updated to dyno section. More developments are underway.

And result to share:

GTX3076R Gen 2 maxed on a built Rb25det Neo on 26psi of boost, externally gated on E85 fuel.

 

59709273_1791193424315303_3772521770397990912_n (1).jpg

I'm curious, why the drop in rpm and hence power/torque on the graphs? 

It's like you back off after starting the run and then hit it again yet your torque/power never gets back up there.

It's a solid drop in 25kw from what I can make out when it does it.

28 minutes ago, MBS206 said:

I'm curious, why the drop in rpm and hence power/torque on the graphs? 

It's like you back off after starting the run and then hit it again yet your torque/power never gets back up there.

It's a solid drop in 25kw from what I can make out when it does it.

That's the dyno having trouble keeping the ramp under control , happens when turbos come on really abruptly.

  • Like 1
Just now, Ben C34 said:

That's the dyno having trouble keeping the ramp under control , happens when turbos come on really abruptly.

Is the rpm reading coming from a calculation on the roller speed or a sensor off the engine? 

The only time I've encountered an issue with ramp rate and having issues was actually that the dyno couldn't keep up with the tyres, at that point power just dropped as the tyres were wheel spinning on the dyno. 

When this happened neither the retarder or the engine rpm dropped like the graph is showing happened. I understand it giving the jittery issue above that, but not a drop in rpm. 

17 minutes ago, MBS206 said:

Is the rpm reading coming from a calculation on the roller speed or a sensor off the engine? 

The only time I've encountered an issue with ramp rate and having issues was actually that the dyno couldn't keep up with the tyres, at that point power just dropped as the tyres were wheel spinning on the dyno. 

When this happened neither the retarder or the engine rpm dropped like the graph is showing happened. I understand it giving the jittery issue above that, but not a drop in rpm. 

This is a hub dyno, so no wheelspin. That's probably why I have only seen it on other dynapack graphs.

Thats in .82 rear housing. Power curve is in response to boost curve, unfortunately I don't have a boost reading.

I've dynoed way more powerful cars on that particular dyno there's not issues with it. The only time I had similar power outline was a boost spike. Might be a delay in ext gate response, boost spiked around 4000RPM, then dropped back to norm. Could be waste gate springs are too hard, gate is jammed, hoses connecting to the external gate is too long or parameters in the EBC not 100%. 

Edited by hypergear
14 hours ago, MBS206 said:

If it's a hub dyno, are you saying the dyno is forcefully slowing the rpm of the engine after a power spike? 

No, it would be the boost spike causing power to rise very rapidly then the response of the controller actually pulls more boost out of it than it needed to and the output drops below where it was and takes a moment to get back - and in that moment the dyno pull has proceeded up the rpms a bit more and you get hole in the curve. It's all about the PID tuning.

1 hour ago, GTSBoy said:

No, it would be the boost spike causing power to rise very rapidly then the response of the controller actually pulls more boost out of it than it needed to and the output drops below where it was and takes a moment to get back - and in that moment the dyno pull has proceeded up the rpms a bit more and you get hole in the curve. It's all about the PID tuning.

If that's the case, you'd get a drop in power as RPm increases. 

This has a drop in power AND rpm meaning it had to slow, right? RPM is measured, graph trace left to right is increasing, to get a loop, rpm had to go right to left, meaning it dropped.  That's what I don't understand. 

17 hours ago, Ben C34 said:

That's the dyno having trouble keeping the ramp under control , happens when turbos come on really abruptly.

Not entirely.  There may be a SLIGHT bit of dyno control issue there but it will mainly be because there was a boost spike and drop from what I can tell looking at it - boost control isn't brilliant and I suspect the dyno would have been trying to ramp up resistance to oppose the rapid increase in torque as the torque was spooling, but then suddenly the boost dropped while the dyno was "anticipating" further torque increase so it may have dragged the rpm down for a split second before it adjusted it's resistance and that would cover the slight loop

1 minute ago, Lithium said:

Not entirely.  There may be a SLIGHT bit of dyno control issue there but it will mainly be because there was a boost spike and drop from what I can tell looking at it - boost control isn't brilliant and I suspect the dyno would have been trying to ramp up resistance to oppose the rapid increase in torque as the torque was spooling, but then suddenly the boost dropped while the dyno was "anticipating" further torque increase so it may have dragged the rpm down for a split second before it adjusted it's resistance and that would cover the slight loop

That explains it more for me. 

Thanks

Don't really like using the Haltech log viewer because you can only see 4 channels at time, a bit shit house - but the playback function is quiet nice.

7 month old E85, tune a little rich lol (just dumped in extra 10%, seems like the new setup wants more fuel).

Because it's double demerits, these runs were done in 2nd, ignore the road speed - it's wrong, I need to configure the ratios.

1 bar ~4000rpm

image.thumb.png.6c553ad9ecd2e555268ad51a9a3fca6a.png

 

1.3 bar ~4300rpm

image.thumb.png.975c0044d6f0b4eb1c0b8dfe0ab3dd6e.png

Maybe after my trip in July, need to still tidy up a few things and see if I can get a 100mm Plazmaman cooler in there first. I suspect the 76mm eBay junk cooler isn't going to do justice.

Also it's developed a misfire when you put in more boost, I wonder if it's fuel related (7 month old E85, car was off the road since November).

Twin scroll is lyfe ?

I suspect loading up the car in 3rd would show more impressive data, however for 2nd gear pulls you can see why I'm impressed for what it is, especially on a pleb 2.5L stock displacement build with Tomei "Poocams" as some call it.

The reasoning behind the "Poocams" is the actual amount of lift for drop in cams. 260/9.15mm is more than anything out on the market that are drop in and support VCT.

Broscience sometimes works lol

37 minutes ago, Dose Pipe Sutututu said:

I suspect loading up the car in 3rd would show more impressive data, however for 2nd gear pulls you can see why I'm impressed for what it is, especially on a pleb 2.5L stock displacement build with Tomei "Poocams" as some call it.

The reasoning behind the "Poocams" is the actual amount of lift for drop in cams. 260/9.15mm is more than anything out on the market that are drop in and support VCT.

Broscience sometimes works lol

Yeah.  3rd gear absolutely would show much better than that, would fully expect it to anyway.  

In regards to RB25 cams which support VCT: https://www.kelfordcams.com/nz/camshafts/nissan/rb25-nvcs/246-a-camshaft-set.html

There are a few guys around here using various spec RB25/VCT Kelford cams and they've been pretty impressive, too.

Edited by Lithium

Oooo those might be new! When I looked at Kelford at the time, they didn't have VCT cams with decent lift.

After I get a new plenum and cooler, the cams might be something I revisit.

Don't think you'd be at a power level where a 76mm plazmaman would be overwhelmed, didn't have any IAT issues with mine doing 700 to the hubs last month. Might make packaging and purchase price a bit nicer

  • Like 1

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

    • Yeah, that's fine**. But the numbers you came up with are just wrong. Try it for yourself. Put in any voltage from the possible range and see what result you get. You get nonsense. ** When I say "fine", I mean, it's still shit. The very simple linear formula (slope & intercept) is shit for a sensor with a non-linear response. This is the curve, from your data above. Look at the CURVE! It's only really linear between about 30 and 90 °C. And if you used only that range to define a curve, it would be great. But you would go more and more wrong as you went to higher temps. And that is why the slope & intercept found when you use 50 and 150 as the end points is so bad halfway between those points. The real curve is a long way below the linear curve which just zips straight between the end points, like this one. You could probably use the same slope and a lower intercept, to move that straight line down, and spread the error out. But you would 5-10°C off in a lot of places. You'd need to say what temperature range you really wanted to be most right - say, 100 to 130, and plop the line closest to teh real curve in that region, which would make it quite wrong down at the lower temperatures. Let me just say that HPTuners are not being realistic in only allowing for a simple linear curve. 
    • I feel I should re-iterate. The above picture is the only option available in the software and the blurb from HP Tuners I quoted earlier is the only way to add data to it and that's the description they offer as to how to figure it out. The only fields available is the blank box after (Input/ ) and the box right before = Output. Those are the only numbers that can be entered.
    • No, your formula is arse backwards. Mine is totally different to yours, and is the one I said was bang on at 50 and 150. I'll put your data into Excel (actually it already is, chart it and fit a linear fit to it, aiming to make it evenly wrong across the whole span. But not now. Other things to do first.
    • God damnit. The only option I actually have in the software is the one that is screenshotted. I am glad that I at least got it right... for those two points. Would it actually change anything if I chose/used 80C and 120C as the two points instead? My brain wants to imagine the formula put into HPtuners would be the same equation, otherwise none of this makes sense to me, unless: 1) The formula you put into VCM Scanner/HPTuners is always linear 2) The two points/input pairs are only arbitrary to choose (as the documentation implies) IF the actual scaling of the sensor is linear. then 3) If the scaling is not linear, the two points you choose matter a great deal, because the formula will draw a line between those two points only.
    • Nah, that is hella wrong. If I do a simple linear between 150°C (0.407v) and 50°C (2.98v) I get the formula Temperature = -38.8651*voltage + 165.8181 It is perfectly correct at 50 and 150, but it is as much as 20° out in the region of 110°C, because the actual data is significantly non-linear there. It is no more than 4° out down at the lowest temperatures, but is is seriously shit almost everywhere. I cannot believe that the instruction is to do a 2 point linear fit. I would say the method I used previously would have to be better.
×
×
  • Create New...