Jump to content
SAU Community

Recommended Posts

And I still have not gotten an answer to whether you guys will accept Mainline dyno numbers.

We will....but here's the problem. Dynos do measure power, but the different brands and models have all got different relationships between the amount of power delivered to the tyre/roller interface and the number that gets spat out of the software after measuring at the retarder. That much is obvious. But I will elaborate.

So here in Australia the dominant brand is Dyno Dynamics, and the accepted relationship between what they report as "measured at the wheels" and the engine is close enough to 80%. And there has been a lot of argument about whether FWD or RWD or AWD have different losses based on the efficiency of the driveline....but in reality the majority of the 25% difference is lost at the tyre/roller interface. And that is a seriously wobbly loss, because you can change it by tying the car down differently, using different tyres etc etc.

Dynos with 2 rollers each wheel probably lose a different amount to dynos that sit the tyre up on a single larger diameter roller. The way the power is transmitted from the roller to the final measuring cell will differ from dyno to dyno. So there is no wonder that the relationship between "measured at the wheels" and true engine power will vary. Now, Dyno Dynamics don't claim that the relationship for their stuff is 75%. That's just a number that has come out of concencus from dynoing cars where the engine power is actually known. And DD do not attempt to tell you what the engine power is. They just report the power they measured, such as it is. Other brands of Dyno in Australia may choose to "calibrate" their dynos to report numbers that will more or less agree with DD in order to align with the majority recognised numbers. Some do. Hub dynos are a complication that we shouldn't talk about here.

Now to the core of the matter. What is the old dyno brand that seemed to be dominant in the US? Was it DynoJet? Something like that? Anyway, from what we could tell from here in Australia, it looked as if that brand was set up to measure the power at the rear and then scale it up to output a number that was supposed to be representative of the actual engine power. Certainly the "losses" seemed to be no more than 10%. And 10% is actually a far more reasonable number for real driveline losses compared to the 25% that a lot of people actually thought was the real loss here in Australia. This led to US dyno numbers looking silly here, as has been alluded to in posts above already. Now....it seems to us that the old "scaled up" approach (which is more flawed than a lot of the other possible approaches, courtesy of the reasons outlined in my second paragraph) has become the dominant method in the US, and a lot of people seem t have forgotten how it got there.

Factor in that the internet has turned everyone into a bunch of e-wankers trying to outcompete on raw power numbers instead of on actual vehicle performance and you get a tendency for people to want to see the higher number, then treat it as gospel, instead of it just being a tuning tool. All a chassis dyno is really suitable for is tuning, not fuelling the e-wank fest.

So a Mainline dyno in the US could still have a different calibration compared to what we might expect here in Oz, and so our willingness to "accept" the numbers is still subject to the bullshit I described above.

The e-wankers are also on the other side of the playing field, don't forget.

Pretty sure this started with "is this the new record for -5's".

Besides the point. Do you have a video of the final power run for this car?

Interested to see how it hussyle

Ps ausi blokes love a good stir and seppos are known for getting but hurt when their 700hp car gets hosed by a ausi 500 hp car so your an easy target

Sadly you joined in the fun and didn't get all America rules the world which is odd... Sure your American ?

  • Like 8

Ps ausi blokes love a good stir and seppos are known for getting but hurt when their 700hp car gets hosed by a ausi 500 hp car so your an easy target

Sadly you joined in the fun and didn't get all America rules the world which is odd... Sure your American ?

Not only that, but I am Texan!!! ;)

I am off work in a few hours so I will be back when I have some time to sit down and go through all of this.

  • Like 3

The e-wankers are also on the other side of the playing field, don't forget.

Pretty sure this started with "is this the new record for -5's".

Besides the point. Do you have a video of the final power run for this car?

Interested to see how it hussyle

FWIW this build has been 1.5 years in the making. During that time I did a lot of research on this site. I've always said that this set up was going to make 550-600 hp. When it made 700 we both thought wow wonder what the record is. I've never seen any -5s that high so I posted it asking what you guys thought. I went with -5s because I was happy with hp in the 550 range.

We will....but here's the problem. Dynos do measure power, but the different brands and models have all got different relationships between the amount of power delivered to the tyre/roller interface and the number that gets spat out of the software after measuring at the retarder. That much is obvious. But I will elaborate.

So here in Australia the dominant brand is Dyno Dynamics, and the accepted relationship between what they report as "measured at the wheels" and the engine is close enough to 80%. And there has been a lot of argument about whether FWD or RWD or AWD have different losses based on the efficiency of the driveline....but in reality the majority of the 25% difference is lost at the tyre/roller interface. And that is a seriously wobbly loss, because you can change it by tying the car down differently, using different tyres etc etc.

Dynos with 2 rollers each wheel probably lose a different amount to dynos that sit the tyre up on a single larger diameter roller. The way the power is transmitted from the roller to the final measuring cell will differ from dyno to dyno. So there is no wonder that the relationship between "measured at the wheels" and true engine power will vary. Now, Dyno Dynamics don't claim that the relationship for their stuff is 75%. That's just a number that has come out of concencus from dynoing cars where the engine power is actually known. And DD do not attempt to tell you what the engine power is. They just report the power they measured, such as it is. Other brands of Dyno in Australia may choose to "calibrate" their dynos to report numbers that will more or less agree with DD in order to align with the majority recognised numbers. Some do. Hub dynos are a complication that we shouldn't talk about here.

Now to the core of the matter. What is the old dyno brand that seemed to be dominant in the US? Was it DynoJet? Something like that? Anyway, from what we could tell from here in Australia, it looked as if that brand was set up to measure the power at the rear and then scale it up to output a number that was supposed to be representative of the actual engine power. Certainly the "losses" seemed to be no more than 10%. And 10% is actually a far more reasonable number for real driveline losses compared to the 25% that a lot of people actually thought was the real loss here in Australia. This led to US dyno numbers looking silly here, as has been alluded to in posts above already. Now....it seems to us that the old "scaled up" approach (which is more flawed than a lot of the other possible approaches, courtesy of the reasons outlined in my second paragraph) has become the dominant method in the US, and a lot of people seem t have forgotten how it got there.

Factor in that the internet has turned everyone into a bunch of e-wankers trying to outcompete on raw power numbers instead of on actual vehicle performance and you get a tendency for people to want to see the higher number, then treat it as gospel, instead of it just being a tuning tool. All a chassis dyno is really suitable for is tuning, not fuelling the e-wank fest.

So a Mainline dyno in the US could still have a different calibration compared to what we might expect here in Oz, and so our willingness to "accept" the numbers is still subject to the bullshit I described above.

Off course even dynos of the same brand will have some sort of variance. I think that is why the USA likes the dynojet stuff because it seams to be the most consistent and there is no way to artificially inflate the HP that it reads other than putting a hair dryer or something on the weather station. But you would still see that in the run conditions.

We work with primarily Chevrolet any more. Started out in the import world. Just an FYI, we see anywhere from 15-20% losses on most cars from their rated crank HP. Any thought on this?

Does anyone one happen to know what any of the factory chevy products are putting down on your dynos?

We have a mainline dyno ordered that should be with us when we move from out current 4500sq/ft facility to our new 18,000 sq/ft building that we have built. So what if we were to just take the dyno out of the crate and run the car? Any reason those numbers would not hold up?

Still want dyno video

Dont have one at the moment

Edited by Jc052685

I must correct one item in my last post. Where I said the DD relationship was 80%, I actually meant 75%. I have no idea how I managed that slip.

And that difference (between our accepted 25% loss and the 15% sort of number bandied around in he US) has often been the source of the inflated flywheel numbers we hear from the US.

As to you setting up a fresh Mainline and giving it a run.....you could ask on here for contacts to a couple of trusted dyno shops here in Oz that use Mainlines to discuss settings to try to make sure you get as close to what they've been doing. Might be worth the effort involved for the comparison.

As to factory Chev stuff here.....not much. There's a few Camaros and 'Vettes running around. Our Commodores use LS engines, but they all have a local tune, so you'd need to take possible difference there into consideration. But there are going to be billions of dyno threads on those cars on other forums. Just be prepared for a higher level of stupidity than you have ever experienced before if you go looking for it.

  • Like 1

Injectors, like others have said don't match the power

My 1250's are totally maxed out at similar hp on what some would say is a generous dyno (when I say totally maxed out they run over 120% duty haha)

pardon my ignorance, but how you open injectors for more than 100% of the time? is it calculating say a 36ms required pulse width when the cycle time is only 30ms, but in reality, the injector has saturated?

Edited by burn4005

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

    • Even more fun, leave all the ADAS stuff plugged in, but in different locations, hopefully avoid any codes!   And honestly, all these new cars with their weird electronics. Pull all the electronics out Duncan, and just shove an aftermarket ECU and if needed a trans controller in, along with a PDM. Make it run basic but race car styled!
    • To follow up a question from earlier too since I had the front bar off again (fking!) This is what is between the bumper and the drivers side wheel And this is the navigator side, only one thing but its a biggy! So basically....no putting coolers in the wheel arches without a lot of moving other stuff. Assuming I move to properly race prepping this car I'll take that job on and see how the computers respond to removing a whole bunch of ADAS modules
    • So I prepped the car for another track day on Wednesday (will be interesting to see coolant temps post flushing out and the larger reservoir, with a forecast of 3-14 being 20o cooler than last time I took it out). Couple of things to mention; since I am just driving the car and not taking a support vehicle, I took the rear seats out and just loaded the back up Team Trackday style. Look at all that space! To cover off removing the rear seat....it is weird (note the hybrid is probably different because it wouldn't have folding rear seats) Basically, you remove the lower seat base, very similar to a r series but it is a clip that pulls forward to release the base rather than it being bolted down. Easy Then, you need to remove the side section of the rear seat on each side. There is a 14mm head nut at the bottom of the side piece, the it slides upwards off a hook at the top to release; you also need to unhook the seatbelt from the loop at the top. Then the centre piece is weird. You need to release/fold the seats forward with the tab in the boot on each side From there, there are 2,x12mm headed bolts holding the rear of each seat to the folding bracket, under the trim between the rear seat and the boot (4x christmas tree clips there, they suck). The seat is out but you can see where the bolts attach to the bracket
    • As discussed in the previous post, the bushes in the 110 needed replacing. I took this opportunity to replace the castor bushes, the front lower control arm, lower the car and get the alignment dialled in with new tyres. I took it down to Alignment Motorsports on the GC to get this work done and also get more out of the Shockworks as I felt like I wasn't getting the full use out of them.  To cut a very long story short, it ended up being the case the passenger side castor arm wouldn't accept the brand new bush as the sleeve had worn badly enough to the point you could push the new bush in by hand and completely through. Trying a pair of TRD bushes didn't fix the issue either (I had originally gone with Hardrace bushes). We needed to urgently source another castor arm, and thankfully this was sourced and the guys at the shop worked on my car until 7pm on a Saturday to get everything done. The car rides a lot nicer now with the suspension dialled in properly. Lowered the car a little as well to suit the lower profile front tyres, and just bring the car down generally. Eternally thankful for the guys down at the shop to get the car sorted, we both pulled big favours from our contacts to get it done on the Saturday.  Also plugged in the new Stedi foglights into the S15, and even from a quick test in the garage I'm keen to see how they look out on the road. I had some concerns about the length of the LED body and whether it'd fit in the foglight housing but it's fine.  I've got a small window coming up next month where I'll likely get a little paint work done on the 110 to remove the rear wing, add a boot wing and roof wing, get the side skirt fixed up and colour match the little panel on the tail lights so that I can install some badges that I've kept in storage. I'm also tempted to put in a new pair of headlights on the 110.  Until then, here's some more pictures from Easter this year. 
    • I would put a fuel pressure gauge between the filter and the fuel rail, see if it's maintaining good fuel pressure at idle going up to the point when it stalls. Do you see any strange behavior in commanded fuel leading up to the point when it stalls? You might have to start going through the service manual and doing a long list of sensor tests if it's not the fuel system for whatever reason.
×
×
  • Create New...