Jump to content
SAU Community

Recommended Posts

anyone can feel free to correct me if im wrong but..

my understanding is that speed graphs mean you cannot really disguise a laggy setup,whereas displaying vs. rpm you can. if for instance the dyno run was done in 5th, you could have the car very very slowly pulling from 2000rpm all the way to redline, and this slow climb in revs would give a massive turbo time to spool by say 3-3500 rpm and by looking at the printout you wouldnt know. This same setup displayed as speed instead of rpm you would see that it was still only making massive boost because it was in 5th up round 200kph, not a useful track/street setup neccesarily.

By displaying in speed this fudge factor is taken out as the dyno tuners are forced to make runs in 3rd or 4th which shows us actual meaningful response times for the power delivery. By knowing roughly your gear ratios and comparing this to the speeds on the dyno chart you can tell what gear the run was done in and thus whether or not to take the responsiveness (or lack of) of the engine with a grain of salt....

Hope this helps

Sean

Link to comment
https://www.sau.com.au/forums/topic/298894-dyno-sheets/#findComment-4970587
Share on other sites

a lot of the time, the car's is calibraded against the dyno speedo. this will tell you the multiplier (diff) datio. if the car is in 4th (1:1 ratio)

if this is done correctly its a good indication on your actual speed. RPM is based off the same calculation of dyno to tacho and is quite often off by a few 100 rpm. that is why most operators leave speed as the reference.

its pretty easy to work out rpm from speed. all you need to know is the diff ratio. and as long as the tyres used are close to the correct rolling diameter you will be right.

sorry I hope some of this makes sense, my head is all over the place., might read it later and see WTF i ment...

Link to comment
https://www.sau.com.au/forums/topic/298894-dyno-sheets/#findComment-4970602
Share on other sites

They don't do it because it takes longer to set them up....that is all.

And it's not / 28 for all cars either. All of our cars run ratios from 3.9 to 4.11 to 4.375 and a few others as well. It gives you an idea but still not 100%.

If you ask your dyno op to hook it up vs rpm then they will. It will just cost you a little more.

Link to comment
https://www.sau.com.au/forums/topic/298894-dyno-sheets/#findComment-4970723
Share on other sites

They don't do it because it takes longer to set them up....that is all.

And it's not / 28 for all cars either. All of our cars run ratios from 3.9 to 4.11 to 4.375 and a few others as well. It gives you an idea but still not 100%.

If you ask your dyno op to hook it up vs rpm then they will. It will just cost you a little more.

TBH most of the guys ive talked to cbf'd doing the setup for each car, i don't have a choice with the dynapack as everything has to be calibrated (rpm matched to within about 5-10rpm) before commencing any runs, its easy and takes about 1min to do.

Link to comment
https://www.sau.com.au/forums/topic/298894-dyno-sheets/#findComment-4970750
Share on other sites

my understanding is that speed graphs mean you cannot really disguise a laggy setup,whereas displaying vs. rpm you can. if for instance the dyno run was done in 5th, you could have the car very very slowly pulling from 2000rpm all the way to redline, and this slow climb in revs would give a massive turbo time to spool by say 3-3500 rpm and by looking at the printout you wouldnt know. This same setup displayed as speed instead of rpm you would see that it was still only making massive boost because it was in 5th up round 200kph, not a useful track/street setup neccesarily.

Not true, the dyno controls the speed the car revs out... so it doesn't really matter which gear it is in, in that respect.

Link to comment
https://www.sau.com.au/forums/topic/298894-dyno-sheets/#findComment-4970752
Share on other sites

Not sure about the other dynos but i know on the dynojet it's just a matter of hooking up the pick up around the loop on the back of the engine for the rpm.

For example, it would just make life sooo much easier to see at what rpm the turbo is on full boost without having to do calculations if u know what i mean!!!

Link to comment
https://www.sau.com.au/forums/topic/298894-dyno-sheets/#findComment-4972796
Share on other sites

I don't see the point of comparing to RPM...

Torque VS Speed is going to be the real winner in a race.

Seeing that a car makes say an average of 500nm of torque across a 70KM range, is much more beneficial then seeing it makes 500nm across a 2000RPM range when you're comparing a vehicle on the track...

Link to comment
https://www.sau.com.au/forums/topic/298894-dyno-sheets/#findComment-4972995
Share on other sites

I don't see the point of comparing to RPM...

Torque VS Speed is going to be the real winner in a race.

Seeing that a car makes say an average of 500nm of torque across a 70KM range, is much more beneficial then seeing it makes 500nm across a 2000RPM range when you're comparing a vehicle on the track...

they are directly related so its a moot point.

Link to comment
https://www.sau.com.au/forums/topic/298894-dyno-sheets/#findComment-4973243
Share on other sites

Possibly be better if, say, comparing quite a few vehicles on one day.. Lots of different final drive ratios, if you kept the charts all referenced to rpm it would be easier to make a comparison?

btw, thats a question not a statement..

Edited by heller44
Link to comment
https://www.sau.com.au/forums/topic/298894-dyno-sheets/#findComment-4973345
Share on other sites

I don't see the point of comparing to RPM...

Torque VS Speed is going to be the real winner in a race.

Seeing that a car makes say an average of 500nm of torque across a 70KM range, is much more beneficial then seeing it makes 500nm across a 2000RPM range when you're comparing a vehicle on the track...

Because you are trying to see what your ENGINE is doing when you put it on a dyno, not how the car will perform. You have the track for that--and don't say suspension/tires don't allow for that, because you can look at mph and just how fast you went down the last half of the 1/4. The power vs. RPM dyno sheets look useless IMHO, and I think it's just the operator not feeling like setting everything up for an RPM reading. Just my opinion though.

Link to comment
https://www.sau.com.au/forums/topic/298894-dyno-sheets/#findComment-4973983
Share on other sites

Because you are trying to see what your ENGINE is doing when you put it on a dyno, not how the car will perform. You have the track for that--and don't say suspension/tires don't allow for that, because you can look at mph and just how fast you went down the last half of the 1/4. The power vs. RPM dyno sheets look useless IMHO, and I think it's just the operator not feeling like setting everything up for an RPM reading. Just my opinion though.

Did you mean Speed vs Power is useless. Or RPM Vs Power is useless. Coz you sound like you are disagreeing and then you agree? Im so lost

Link to comment
https://www.sau.com.au/forums/topic/298894-dyno-sheets/#findComment-4974037
Share on other sites

Because you are trying to see what your ENGINE is doing when you put it on a dyno, not how the car will perform. You have the track for that--and don't say suspension/tires don't allow for that, because you can look at mph and just how fast you went down the last half of the 1/4. The power vs. RPM dyno sheets look useless IMHO, and I think it's just the operator not feeling like setting everything up for an RPM reading. Just my opinion though.

Or if you actually do a full gearbox dyno pull you can see exactly where the perfect shift points are.

Can't do that with RPM... :D

Link to comment
https://www.sau.com.au/forums/topic/298894-dyno-sheets/#findComment-4974122
Share on other sites

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

    • I came here to note that is a zener diode too base on the info there. Based on that, I'd also be suspicious that replacing it, and it's likely to do the same. A lot of use cases will see it used as either voltage protection, or to create a cheap but relatively stable fixed voltage supply. That would mean it has seen more voltage than it should, and has gone into voltage melt down. If there is something else in the circuit dumping out higher than it should voltages, that needs to be found too. It's quite likely they're trying to use the Zener to limit the voltage that is hitting through to the transistor beside it, so what ever goes to the zener is likely a signal, and they're using the transistor in that circuit to amplify it. Especially as it seems they've also got a capacitor across the zener. Looks like there is meant to be something "noisy" to that zener, and what ever it was, had a melt down. Looking at that picture, it also looks like there's some solder joints that really need redoing, and it might be worth having the whole board properly inspected.  Unfortunately, without being able to stick a multimeter on it, and start tracing it all out, I'm pretty much at a loss now to help. I don't even believe I have a climate control board from an R33 around here to pull apart and see if any of the circuit appears similar to give some ideas.
    • Nah - but you won't find anything on dismantling the seats in any such thing anyway.
    • Could be. Could also be that they sit around broken more. To be fair, you almost never see one driving around. I see more R chassis GTRs than the Renault ones.
    • Yeah. Nah. This is why I said My bold for my double emphasis. We're not talking about cars tuned to the edge of det here. We're talking about normal cars. Flame propagation speed and the amount of energy required to ignite the fuel are not significant factors when running at 1500-4000 rpm, and medium to light loads, like nearly every car on the road (except twin cab utes which are driven at 6k and 100% load all the time). There is no shortage of ignition energy available in any petrol engine. If there was, we'd all be in deep shit. The calorific value, on a volume basis, is significantly different, between 98 and 91, and that turns up immediately in consumption numbers. You can see the signal easily if you control for the other variables well enough, and/or collect enough stats. As to not seeing any benefit - we had a couple of EF and EL Falcons in the company fleet back in the late 90s and early 2000s. The EEC IV ECU in those things was particularly good at adding in timing as soon as knock headroom improved, which typically came from putting in some 95 or 98. The responsiveness and power improved noticeably, and the fuel consumption dropped considerably, just from going to 95. Less delta from there to 98 - almost not noticeable, compared to the big differences seen between 91 and 95. Way back in the day, when supermarkets first started selling fuel from their own stations, I did thousands of km in FNQ in a small Toyota. I can't remember if it was a Starlet or an early Yaris. Anyway - the supermarket servos were bringing in cheap fuel from Indonesia, and the other servos were still using locally refined gear. The fuel consumption was typically at least 5%, often as much as 8% worse on the Indo shit, presumably because they had a lot more oxygenated component in the brew, and were probably barely meeting the octane spec. Around the same time or maybe a bit later (like 25 years ago), I could tell the difference between Shell 98 and BP 98, and typically preferred to only use Shell then because the Skyline ran so much better on it. Years later I found the realtionship between them had swapped, as a consequence of yet more refinery closures. So I've only used BP 98 since. Although, I must say that I could not fault the odd tank of United 98 that I've run. It's probably the same stuff. It is also very important to remember that these findings are often dependent on region. With most of the refineries in Oz now dead, there's less variability in local stuff, and he majority of our fuels are not even refined here any more anyway. It probably depends more on which SE Asian refinery is currently cheapest to operate.
    • You don't have an R34 service manual for the body do you? Have found plenty for the engine and drivetrain but nothing else
×
×
  • Create New...