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Best Dyno for Tuning #1428328
20/05/2013 23:25
20/05/2013 23:25
Joined: Dec 2005
Posts: 554
Nottingham
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Cyclone Offline OP
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A friend has a 20VT and is looking at tuning options, it is currently just running an uprated turbo / chip. I have advised him to stick to one Dyno to get a base reading and then keep re-using this dyno as the mods are applied.

As I don't visit the forum that often and have lost touch my question is;

is there a dyno of choice in the Coupe world, one where most Coupes have ran for comparison purposes, or should I just recommended a tried and tested source such as SRR?

Cheers Jules

Re: Best Dyno for Tuning [Re: Cyclone] #1428332
21/05/2013 00:00
21/05/2013 00:00

B
Barbz
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Barbz
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Go to SRR, the most accurate so far, as proven at the last meet.
smile

Re: Best Dyno for Tuning [Re: Cyclone] #1428392
21/05/2013 09:39
21/05/2013 09:39
Joined: Jan 2006
Posts: 3,034
Sweden
Per Offline
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Sweden
Was wondering too, have had big problems with my boost not maxxing because of the rollers being too light. On road the max boost is 0.2bar higher. (yes I have OE ECU controlled boost - which I love in every other sense)
Result: I STILL don't know exactly if I have sufficiant fuel at top whack..
Is there a certain type I should look for?

Re: Best Dyno for Tuning [Re: Per] #1428411
21/05/2013 10:45
21/05/2013 10:45
Joined: Dec 2005
Posts: 12,293
Sandhurst
Begbie Offline
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Originally Posted By: Per
Was wondering too, have had big problems with my boost not maxxing because of the rollers being too light. On road the max boost is 0.2bar higher. (yes I have OE ECU controlled boost)
Result: I STILL don't know exactly if I have sufficiant fuel at top whack..
Is there a certain type I should look for?

Exactly the same problem everytime I have been to the dyno mentioned above by Barbz. Both times the boost has been lower than what I generate on the road.


Originally Posted by Jonny - After being taken out at Spa
Your car is Usain Bolt with wellies
Re: Best Dyno for Tuning [Re: Cyclone] #1428412
21/05/2013 10:47
21/05/2013 10:47

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Biggenz
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That's cos you run a girl's boost. laugh

Re: Best Dyno for Tuning [Re: ] #1428413
21/05/2013 11:16
21/05/2013 11:16
Joined: Oct 2006
Posts: 1,829
kidderminster
nick_d Offline
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Agreed!! smile



368bhp @ 1.5 bar
Re: Best Dyno for Tuning [Re: nick_d] #1428422
21/05/2013 11:47
21/05/2013 11:47
Joined: Dec 2005
Posts: 12,293
Sandhurst
Begbie Offline
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Originally Posted By: nick_d
Agreed!! smile

You run the same as me! rofl

First time I ran on SRR it was 1.4bar on the road and 1.2 on the dyno.
Last time on SRR it's 1.5bar on the road and 1.35bar spike then running 1.3bar on the dyno

Both times loosing 0.2bar


Originally Posted by Jonny - After being taken out at Spa
Your car is Usain Bolt with wellies
Re: Best Dyno for Tuning [Re: ] #1428440
21/05/2013 12:50
21/05/2013 12:50

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Barbz
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Biggenz's boost was pretty cock on, but the heart breaker for him, 60hp down from his Dastek figure. tongue

My target boost was set to 2.15bar but only saw 1.9bar at Surrey, still only 35hp down on JDM's figure recorded at 2.15bar. wink

I'm happy with 500hp ish, its all about the torque and spread of power for me laugh

Re: Best Dyno for Tuning [Re: Cyclone] #1428444
21/05/2013 13:00
21/05/2013 13:00
Joined: Feb 2008
Posts: 1,725
London
kj16v Offline
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SRR has a Dyno Dynamics dyno. When I tune, I use one of three different dynos, depending on the car and availability: I use a Dyno Star, a Dyno Dynamics and a Dastek.

For mapping it doesn't make a bit of different which one you use because, when mapping, you set the load to whatever you need. However for making power runs, dynos use a different mode -To keep this short I won't go into the details of the modes.

I personally find that The Dastek and Dyno Dynamics are better for power runs on N/A vehicles, wheres the Dyno Star I use tends to over-read on N/A cars (well - on Clios at least).

However, I prefer the Dyno Star for doing power runs on turbocharged vehicles. It loads the engines in a very similar way to they are on the street, so yo get an accurate boost "profile". It also manages to spin up quite quickly, so it cuts down the amount of time the engine spends under heavy load, which I like. I've compared

I stress the word "personally" above, because choices of dynos are somewhat a matter of personal taste. What I say above is what I've found in my own experience in my years of tuning. (I add this disclaimer because one or two people like to beat their chests about this sorts of things, lol!)

I think a lot of problems people have with boost on dynos comes from boost control. I think a fair few people (tuners included) really "get" boost control. One thing I see very, very often is people trying to hold high boost levels with inadequate wastegate springs. A weak wastegate spring will never hold high boost, no matter what type of boost control you use - MBC, EBC, sourcery, etc. Not saying that's definitely the problem with you guys above, but it is something I see a lot.

I personally like to keep boost control simple, use an actuator spring that's closest to the maximum boost I wish to run only use minimum boost control to make small adjustments (up to psi). For example, on my 16VT I use an external wastegate with a 1.5 bar spring rate - and that's it. No boost controller. I do have a bleed valve for small adjustments, but to date it remains closed. The result is the turbo spools as quick as physics will allow and the car makes 1.5 bar everywhere; on the road and on any dyno, from DD to DS.

Also, I'm not a fan of stock ECU boost control - never seems to control boost reliably under all conditions. - some situations but not others, some dynos, but not others...

Re: Best Dyno for Tuning [Re: Begbie] #1428446
21/05/2013 13:04
21/05/2013 13:04
Joined: Feb 2008
Posts: 1,725
London
kj16v Offline
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Originally Posted By: Begbie
Originally Posted By: nick_d
Agreed!! smile

You run the same as me! rofl

First time I ran on SRR it was 1.4bar on the road and 1.2 on the dyno.
Last time on SRR it's 1.5bar on the road and 1.35bar spike then running 1.3bar on the dyno

Both times loosing 0.2bar


Yeah and me! Some of us just make better use of the boost we got! tongue biglaugh

Re: Best Dyno for Tuning [Re: kj16v] #1428460
21/05/2013 13:59
21/05/2013 13:59
Joined: Oct 2006
Posts: 1,829
kidderminster
nick_d Offline
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kidderminster
Benders!! smile
I actually run 1.65-1.7 bar.....
Difference is my turbo in comparison to yours (Smegbie & gay jays) smile
Is quite abit smaller and is on its knees at around 1.7 bar.
Where as your monster compressors haven't even whiped the sleep from their eyes at a miserly (but very safe/Gay) 1.5 bar!!

Anyway back on topic.... My car Never reaches peak boost on any Dyno... 1.5 on Fleas dastek... 1.45 on Dyno jet,
I would say that the Dyno jet graph seemed more accurate to how the car drives on the road with peak torque at between 3800-4000 revs then slowly falls as boost tails off (tiny turbine wheel).

The Dyno jet did have a feature/component called "Eddy Retarder" which when altered between 1st & 2nd runs allowed peak boost to rise from 1.3 to 1.45... Maybe if he'd have adjusted a little more we may have got my "on road" peak boost?

Nick

Last edited by nick_d; 21/05/2013 14:00.


368bhp @ 1.5 bar
Re: Best Dyno for Tuning [Re: kj16v] #1428506
21/05/2013 16:48
21/05/2013 16:48

B
Barbz
Unregistered
Barbz
Unregistered
B



Quote:
SRR has a Dyno Dynamics dyno. When I tune, I use one of three different dynos, depending on the car and availability: I use a Dyno Star, a Dyno Dynamics and a Dastek.

For mapping it doesn't make a bit of different which one you use because, when mapping, you set the load to whatever you need. However for making power runs, dynos use a different mode -To keep this short I won't go into the details of the modes.

I personally find that The Dastek and Dyno Dynamics are better for power runs on N/A vehicles, wheres the Dyno Star I use tends to over-read on N/A cars (well - on Clios at least).

However, I prefer the Dyno Star for doing power runs on turbocharged vehicles. It loads the engines in a very similar way to they are on the street, so yo get an accurate boost "profile". It also manages to spin up quite quickly, so it cuts down the amount of time the engine spends under heavy load, which I like. I've compared

I stress the word "personally" above, because choices of dynos are somewhat a matter of personal taste. What I say above is what I've found in my own experience in my years of tuning. (I add this disclaimer because one or two people like to beat their chests about this sorts of things, lol!)

I think a lot of problems people have with boost on dynos comes from boost control. I think a fair few people (tuners included) really "get" boost control. One thing I see very, very often is people trying to hold high boost levels with inadequate wastegate springs. A weak wastegate spring will never hold high boost, no matter what type of boost control you use - MBC, EBC, sourcery, etc. Not saying that's definitely the problem with you guys above, but it is something I see a lot.

I personally like to keep boost control simple, use an actuator spring that's closest to the maximum boost I wish to run only use minimum boost control to make small adjustments (up to psi). For example, on my 16VT I use an external wastegate with a 1.5 bar spring rate - and that's it. No boost controller. I do have a bleed valve for small adjustments, but to date it remains closed. The result is the turbo spools as quick as physics will allow and the car makes 1.5 bar everywhere; on the road and on any dyno, from DD to DS.

Also, I'm not a fan of stock ECU boost control - never seems to control boost reliably under all conditions. - some situations but not others, some dynos, but not others...


Thanks for your input and experience. cool

Can dyno figures be exaggerated easily to serve a tuners marketing agenda?

Thanks
Barbz

Re: Best Dyno for Tuning [Re: ] #1428622
21/05/2013 23:55
21/05/2013 23:55
Joined: Feb 2008
Posts: 1,725
London
kj16v Offline
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kj16v  Offline
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Joined: Feb 2008
Posts: 1,725
London
Originally Posted By: Barbz
Thanks for your input and experience. cool

Can dyno figures be exaggerated easily to serve a tuners marketing agenda?

Thanks
Barbz


No probs smile

Yep certainly can. It's easy to get exaggerated figures out of a dyno. For example: the dyno software needs an rpm reading in order to calculate horsepower **bhp = (torque x rpm) / 5252** The tuner/dyno operator can take a direct reading via an inductive pickup connected to an HT lead. But more often they will use a reading calculated from the wheel speed; The car is held at 3000 rpm indicated on the dashboard tacho, then the dyno software stores the wheel speed at that point and uses it to calculate the rpm with reference to wheel speed. This is absolutely fine; it saves the dyno operator time getting to HT leads to connect to. Not to mention, some cars (like 20VTs) don't have HT leads.

However this does leave room for potential 'naughtiness'. An tuner could underhandedly (or just plain accidentally) set the 3k point too low. So the dyno thinks the engine is revving higher than it really is. So, say, your car's making 400 lbsft @ 5500 rpm, that works out as 419 bhp. However if the dyno thinks you're making 400 lbsft @ 6000rpm: ta-da, 457 bhp. Instant +38 bhp.

Another thing is being "selective" of which dyno results a tuner prints. Throughout a tuning session you'll usually do many power runs. Some of those will come out with wildly inaccurate results. For example due to wheelspin on the rollers, or heatsoak, etc, etc. It can be very tempting (I know!) to print the result with the lowest reading as your "before" reading and print the highest reading result as your "after" result, despite the fact they may not bare any relation to the actual trend of results throughout the tuning session.

A tuner can also be sneaky with the results graph itself, if they wish. If you've ever looked at two results graphs and wondered why one looks all jagged like a rocky mountain but the other is a perfectly smooth line, it's because the graphs have been "smoothed". Dyno software usually allows you different levels of smoothing, from light to heavy. The idea is that it makes the final printout easier for the customer to read.
This isn't necessarily a bad thing, but it is possible to hide a multitude of tuning sins by heavily smoothing the graph, eg. hiding flat-spots, or jagged torque lines due to (for example) poor boost control.

That's not to say that all smoothed graphs are hiding things, its just important to be aware of what you're looking at and to know that ALL dyno graphs are bumpy. The one's that are perfectly undulating have been smoothed to a lesser or greater extent - not because the tuner responsible for the graph is stupendously awesome!

I personally never use the smoothing option on a dyno printout. Mainly because it's no use to me as a tuner. The lumps and bumps can show up important issues, not only to do with the engine but in the drivetrain too. For example a flat-spotted or under-inflated tyre can sometimes show up on a graph. For me unedited graphs are tuning tools, whereas smoothed graphs are only useful as publicity tools.

Next time I'm on a dyno I'll have to see if I can print off some examples to illustrate what I mean.

Re: Best Dyno for Tuning [Re: Cyclone] #1428660
22/05/2013 09:27
22/05/2013 09:27
Joined: Dec 2005
Posts: 554
Nottingham
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Cyclone Offline OP
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Cyclone  Offline OP
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Joined: Dec 2005
Posts: 554
Nottingham
Some great info there, appreciate the feedback.

KJ16v, are there any other methods to trick the dyno, e.g. the way cars are strapped down and also running lower than quoted tyre pressures?

Jules.

Re: Best Dyno for Tuning [Re: Cyclone] #1428663
22/05/2013 09:37
22/05/2013 09:37

B
Barbz
Unregistered
Barbz
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B



Quote:
Some great info there, appreciate the feedback.


Yes, definately contributed something very informative to the Tuning area, where power figures seem to mean everthing these days. laugh

Re: Best Dyno for Tuning [Re: Cyclone] #1428680
22/05/2013 10:42
22/05/2013 10:42
Joined: Aug 2000
Posts: 9,729
Zele, Belgium
Kayjey Offline
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Zele, Belgium
The software can also receive some keyboard inputs, resulting in offsetting the power with a certain amount or percentage. Or play around with the temperature input (either manually or playing with the sensors), pull the handbrake on slightly on a four-wheel roller,... If a dyno guy wants to be unethical, he can. It's a matter of trust. I know a lot of stories, including exhausts receiving a little invisible piercing to get a more sporty 'tuned' sound.


- Kayjey -

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Re: Best Dyno for Tuning [Re: Cyclone] #1428686
22/05/2013 11:24
22/05/2013 11:24
Joined: Dec 2005
Posts: 5,405
Castle Combe
Flea Offline
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For a Dyno Dynamics, which measures wheel power only, it is very important to strap the car down correctly with correct tyre pressures in order to stop it lifting out of the dyno. They use small rollers so it must stay planted and in contact with both rollers to work correctly. You must also use the correct mode and gear, especially in shootout which is meant to lock things down. Incidentally there is no 5 cylinder mode, so technically it will always be wrong for a five pot engine. The weather station must also be located in a free air environment so as not to distort corrections. Finally make sure the car is in good order with no transmission issues e.g. binding brake, underinflated tyres, low gearbox oil, as this will cause wheel power to be far lower.

For a coastdown dyno that measures losses, well the primary way to distort flywheel figures is to put the brakes on during the coastdown when the car is in neutral. This will give bigger losses and inflate flywheel power, but it is easily observed as there will be a bigger percentage loss between wheel and flywheel power. We do not have to worry about tyres or transmission issues as the coastdown will allow us to still get correct flywheel figures, and also point out that there is a problem with the transmission.

Choosing the correct dyno mode is very important if you are actually trying to measure how the car performs on the road. The Dastek dyno I use has three different ramp rates according to an eddy load cell, this is great for steady state tuning but can be far too slow to measure accurate power figures without heat being a significant factor. Therefore for power runs, and especially high powered cars, I use inertia as this faster ramp allows the engine to behave much closer to how it performs on the road. How do I know this? Well all the data I receive correlates with the road much more closely with inertia, so I know that I am measuring the same thing. For modern cars that use very accurate mass airflow sensors, I can calculate the engine horsepower without the dyno usually within 5-15bhp depending on how aggressive the tune is. It is very interesting to observe the airflow being consumed by the engine on the road and then compare to the dyno as it will reveal exactly what is happening to the combustion cycle. On some cars I can see a 30-50bhp power drop between a loaded run compared to inertia, so which one is accurate? Well I only have to look at the airflow figures to see that they are both accurate. The difference being that the loaded run has induced so much heat within the engine that is far less efficient and does in fact consume less air. So what we have here is a scenario of having to choose the real power figures given that under both circumstances they are both true. This is where we revert back to the road, whatever the airflow readings are on the road, well that's what we should be measuring on the dyno so the correct mode to replicte this should be used.


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Re: Best Dyno for Tuning [Re: Cyclone] #1428721
22/05/2013 13:12
22/05/2013 13:12
Joined: Dec 2005
Posts: 554
Nottingham
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Cyclone Offline OP
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Nottingham
Really great info Guys, much appreciated.

Flea, on a Dyno Dynamics assuming the car is being in ran in shootout mode, then I am guessing it assumes a set tyre inflation rate? If you ran with lower pressures would this give a higher or lower power figure?

Jules.

Re: Best Dyno for Tuning [Re: Cyclone] #1428745
22/05/2013 15:29
22/05/2013 15:29
Joined: Feb 2008
Posts: 1,725
London
kj16v Offline
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Originally Posted By: Cyclone
Some great info there, appreciate the feedback.

KJ16v, are there any other methods to trick the dyno, e.g. the way cars are strapped down and also running lower than quoted tyre pressures?

Jules.


Yeah. As mentioned above, playing with the settings for atmospheric temperature, pressure and/or humidity can be used to 'tweak' bhp readings nicely, eg. changing the temperature setting to read hotter than it actually is will increase the final bhp calculation.

Running incorrectly inflated tyres will usually work against the dyno operator; if under-inflated, the the dyno wheel read lower wheel horsepower figures. if the tyres are over-inflated they might slip on the rollers, again making it read lower.

The Shootout modes on DD rollers estimate estimate flywheel figures based on DD's own calculations for the average transmission losses of different engine configurations. You can have the tyres inflated at whatever is optimal for the particular car. The important thing to get as repeatable and reliable figures is to inflate the tyres by the same amount every you use that dyno (same goes for any make of dyno really).

The shootout modes currently available are as follows:

Shoot_4 Naturrally-Aspirated 4-cylinder
Shoot_6 N/A 6-cylinder
Shoot_8 N/A 8-cylinder
Shoot_4F 4-cylinder forced induction
Shoot_6F 6-cylinder forced induction
_8F 8-cylinder forced induction
_2R N/A twin rotor Wankel engine
_3R N/A triple rotor Wankel
_44 4-cylinder all-wheel drive
Shoot_81 Very high performance eight cylinder passenger cars requiring higher ramp rates

Note there's no 5-cylinder option!


Last edited by kj16v; 22/05/2013 15:43.

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