Jump to content
SAU Community

Recommended Posts

Anyway of comparing torque figures from 2 different dynos?

See attached images. Old graph (Dyno Dynamics), with higher power and lower torque was done 3-4yrs ago using SAFC and SITC.

The only change, new graph on Mainlne, was a Nistune, so I could have some proper off boost/part throttle behaviour and smooth out that torque dip (through controlling the inlet butterflies properly).

Is there any way to compare the very different torque readings wit the info at hand? 

Cam.thumb.JPG.19ac6512cfead26d97f8cc93b12b6b38.JPG

 

 

received_469312163404959.thumb.jpeg.b6529dae1e9cd21c20f29da9f23d168f.jpeg

received_469312170071625.thumb.jpeg.24a343999129b10d94628550a06caac1.jpeg

Just back calculate a torque number from the power using the normal formula.  It won't be numerically correct, but because it comes from the only thing that actually matters (power at the roller) at least you're starting from the same basis* and can draw graphs to compare.

 

*of course, excepting the different dynos, operators, tyres, years in between, etc etc etc.

I have torque numbers from both dynos. They are very different (360Nm vs 550 or so). 

I know power is just a function of torque vs revs, but given these dynos do various corrections to get their numbers, I have no idea how to apply anything to either number to find something meaningful between them. 

 

 

 

It's because the operator on the Mainline didn't use an inductive pickup OR setup the derived RPM via syncing RPM.

Once that is enabled you can select show 'Derived Torque' 

/Thread 

Even when plugging figures into calculators with known RPM, the output is not like either graph. 

All smoke and mirrors. 

Oh well, see how it goes Sunday and will just hope that a smoother graph means a better car to drive (yes i know graphs can be smoothed also).

Also the power diffence is sfa when considering its 2 differnt dynos on 2 different days, I'd love to see the boost plot from the dd run as a tiny overboost would explain the hump around 4g on the dd graph

Also the 550nm mainline number in this case would definitely be the bs number as with out a rpm trace there's no way it can give torque reading with reference to the engine

 

  • Like 1

If you are not measuring the same car on the same dyno on the same day a good way of telling the improvement is to compare say 80 to 120 km/hr times - too late for you now of course. Does the car feel better to drive now?

1 hour ago, Scott Black said:

Also the power diffence is sfa when considering its 2 differnt dynos on 2 different days, I'd love to see the boost plot from the dd run as a tiny overboost would explain the hump around 4g on the dd graph

Also the 550nm mainline number in this case would definitely be the bs number as with out a rpm trace there's no way it can give torque reading with reference to the engine

 

Boom! Someone that knows :)

Quick report from track day. 

Car felt gutless, no surge of torque when it comes on boost. Also a little bit pinging somewhere up in 3rd, was not logging so cannot tell. Had a few misses/hesitation when cornering (car has surge tank setup) though tuner did note fuel pressure was fluctuating quite a bit with temperature. 

Despite the car feeling gutless and less powerful than I remember it (a few years ago) the max top speed down the straight was identical and the lap time was within 1 tenth of the previous PB 0_0

 

 

Given the max top speed was the same, I'd say so. 

Though I need my old phone to look at the Race Chrono data and see if the corner exit speed onto the straight is the same to be sure. 

Not after seeing GT-Rs "economy" on e85 and the fact I can't get it here. Annoying enough bringing back 80L at ta time for the GTR (which ate 140L at winton...) 

Silvia wouldn't be as bad, but still. That means injectors and a full retune on e85, or additional e-flex sensor then really should go to proper boost control etc etc. 

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

    • To expand on this to help understanding... The bigger/longer the block is, the more it's going to work to sit on your far away high areas, and not touch the low stuff in the middle. When you throw the guide coat, and give it a quick go with a big block, guide coat will disappear in the high spots. If those high spots are in the correct position where the panel should be, stop sanding, and fill the low spots. However, using a small block, you "fall off" one of the high spots, and now your sanding the "side of the hill". Your little block would have been great for the stone chips, where you only use a very small amount of filler, so you're sanding and area let's say the size of a 5/10cent piece, with something that is 75*150. For the big panel, go bigger!   And now I'll go back to my "body work sucks, it takes too much patience, and I don't have it" PS, I thought your picture with coloured circles was an ultra sound... That's after my brain thought you were trying to make a dick and balls drawing...
    • Oh I probably didn't speak enough about the small sanding block for blocking large areas.  In the video about 3 minutes in, he talks about creating valleys in the panel. This is the issue with using a small sanding block for a large area, it's way too easy to create the valleys he is talking about. With a large block its much easier to create a nice flat surface.  Hard to explain but in practice you'll notice the difference straight away using the large block. 
    • Yep I guessed as much. You'll find life much easier with a large block something like this -  https://wholesalepaint.com.au/products/dura-block-long-hook-loop-sanding-block-100-eva-rubber-af4437 This is a good demo video of something like this in use -    You have turned your small rock chip holes into large low spots. You'll need to fill and block these low spots.  It's always a little hard not seeing it in person, but yes I would go ahead and lay filler over the whole area. Have a good look at the video I linked, it's a very good example of all the things you're doing. They went to bare metal, they are using guide coat, they are doing a skim coat with the filler and blocking it back. If what you're doing doesn't look like what they are doing, that's a big hint for you  
    • The odometer does go up when driving.  Does this tell it is an issue with the speedometer itself?    Where can I look for replacement cluster? Or speedo? I can likely do the repair.. Will ER34 cluster work on HR34? Or do I need a HR34 20GT S2 specifically lol   
    • Mine's a bit bigger at 70x150mm roughly. The spots are flat, just can feel the edges if I dig my nail into it. I did fix some other other ones by both using my finger to sand that small spot (I'm a bit wary of doing this and creating hot spots and a bigger mess) and I also did sand over it flat and others, but this also worried me a bit because if I create an overall low spot on the panel on paint that is good.  Correct me if I'm wrong but as long as it's flat even if I can feel the edges, I can put filler because it will all be level once I sand it? I can see myself going in a circle after sanding guidecoat with 320 grit if for example the panel is flat with my hand but because I sanded the guidecoat I could have created a low spot again somewhere. Unless where I'm going wrong is what I mentioned previously where I didn't go low enough on the grits. It's 1 step forward and 2 step backwards here haha. I'll probably need to experiment with it more. Last time I go back to bare metal lol.
×
×
  • Create New...