This thread has been born,cos i dont really have an understanding of how to get an accurate power test performed for my car and im even more confused since i followed the recent threads about it on LOC and other forums.I followed a link from Jays thread which was in relation to a Dyno centre in Bristol.After reading the guide i started to understand a little regarding the prep etc and what to expect .Since then i spoke to a guy on another forum,after forwarding the link to him and he sent me a response about it,also talking of another tuner that was also involved in the discussion.his response is below with the link from the bristol dyno centre.If someone who is either an expert or someone that has a good understanding of how to perform an ideal test,could you please tell me if he is correct in his assesment of the bristol dyno centre or is he wrong.Also which is the best dyno company to use?what i mean is,who is regarded the best in the country?would it be a tuner that deals with race teams etc or a tuner that deals with road cars,or would it make no difference?cheers in advance

http://www.bristoldyno.com/info/procedure.htm




the nice chaps response below--

Hmm,
I am not declaring to be an expert and would welcome comments from others to correct any errors... BUT.
I work as an acoustic engineer and design bespoke packages. I have designed a rolling road cell based on information provided by Dyno Dynamics WRT airflow etc. This required me to select the fans, construction of the dyno cell and ducting/attenuation as required.
I have mapped cars both on road and on a dyno (my own personal track toys) I do not do this bit for a living or claim to know all there is about it but have some experience.
That Bristol Dyno setup is pretty poor IMHO. His fan is totally inadequate for any high power application over a sustained period. Thorney use 2 fans blowing & 2 fans sucking with a claimed 130,000 CFM (I suspect it results in a maximum of 65,000 CFM of airflow through the actual dyno cell as they are in a series-parralel arrangement). From memory Dyno Dynamics suggest a minimum of 45,000 CFM and this is quite difficult to achive with 2 fans of sizes approximate to Thorney's (hence my cooment that 65,000 CFM is most likely- which is more than adequate).

Sorry off topic a bit there...

Bristol Dyno seems to be a rolling road operator not a tuner/mapper. This may be suitable for a race team where you bring your own expert along but for the average Jo it is pointless. I am not a fan of the inertial type dyno he has, it does not allow enough control of conditions to correctly map or for varying power vehicles. Try running a turbocharged car on a dyno with little resistance and you will not get full boost or boost will not come in until very late.
His text is OK but even for a power run I would always want AFR plotted (to check it is fuelling correctly) and det cans used (to check for detonation) as I would want to know it is running as it should and more importantly it is running safely!

As a guide for things to do before you go to a dyno:-
1) Ask yourself what you want from it. Bragging rights, diagnostic, Tuning/mapping.
2) Adjust/check tyre pressures (personally on a dyno I run 50psi - not reccomended for the journey there)
3) Check all fluids & ignition components (includes checking for leaks as oil on the rollers tends to offend & ruin the day)
4) Check your car has no issues, suspension misalignment , worn wheel bearings/CV joints, brake binding, clutch dragging/slipping can prevent you running.
5) Fill up the tank with fresh, highest qulaity gas ( running out of fuel mid way through mapping is a PITA) Fresh gas will also typically have a higher opctane rating.

As a general guide:-
Select one trusted dyno and repeat the dyno run after a modification to compare with original. (Thorneys comment that before & after figures are most important is 100% correct.) Ideally compare power at the wheels with power at the wheels IMHO (reduces any fudge factor & who cares if your car is 100bhp more powerful at the flywheel when you have less at the actual wheels to accelerate you along).
Running your car against similar cars (with/without additional modifications) will only allow you to evaluate how your car fares against others to see the typical gains from modifications (or if your car is poorly!). Don't get excited/ downhearted if you are above or below the magic no. you expected.

A chassis dyno is a tool to gain more performance but can be used to make your ***** bigger.

Sorry if I waffled...

Excellent write up and rather intriguing.

Thank you for that

Jamie

tbh jamie im majorly confused and my car is being dropped off monday morning for SC and i havent even got a true reading of what its making now-i feel that is important,otherwise the results of the supercharging will be pointless.Im gonna have to get it done before i drop it off and although the tuner im using perform power runs all day long,i decided its pointless unless i get it done independently.sorry to drag the amount of info on but he has since wrote back with the following response,and im still trying to work out where is the best place to take it-no one seems to know the answer to that on every forum ive been on,and ive been on about 6 with this discussion.






A) I would want someone to check the revised map (have the ability to re-map if required too) immediately before I drove off. (ideally I would trailor it to a respected M3 tuner with Dyno) I have not seen a great deal of info on this setup but I have seen quite a few "plug & Play" maps being way out on fuelling.

I would want a dyno operator/mapper who understood the limitations of the specific engine components to identify any problems before they arise. Also what the engine likes WRT AFR & timing for a good safe power. (this is an experience thing )

C) If they are a professional mapper they should have at minimum - wideband Lambda analysis equipment, Means of checking the timing is safe (Det cans ideally as the ear is teh best sensor for this! unless BMW has installed the new type knock sensors per cylinder?)

D) Personally I feel road mapping is a mugs game - look for a good quality chassis dyno, it is quicker, more accurate and repeatable. (fancy someone doing 8K rpm in 3rd & 4th gears on the road?)

Personally I think you need to look for good & trusted mappers - not necesarily dyno's. You can buy a good dyno but experience & knowledge you either have or don't. I like Dyno Dynamics dyno's as seem do almost all companies that are making any investment in mapping these days. Dastek may dissagree....
.

A chassis dyno is a tool in that it is designed to maximise your fuelling and timing parameters to achieve the highest possibel power from the engine whilst being safe. It is not really designed to just eb used to give teh average punter a bhp number but it can and the market for thsi has grown so it makes sense for owners to reclaim soem of the purchase costs this way. Most trusted mappers do not care what the actual BHP no. is - there goal is to maximise the cars potential, be it 30bhp or 300bhp.

the company who is doing the work should have a dyno or have access to one. This could be used for the before & after.

From what they are doing to your car I'd hope they'd make sure AFR etc was all as it should be.

looking for someone independant Steve @ Charlesworth uses a chap for my work who is very good. I can also recommend TTS at Silverstone who have also done RR stuff for me. Abbey Motorsport are also really good. Hope this helps

I've read on Dyno day threads on other forums that the majority of M3's don't seem to make the claimed standard 343bhp. The average seems to be around 325 - 335bhp so it would be good if you could get a before run done from somewhere so you can determine your starting point correctly.

Good Luck.........exciting (and expensive!) times ahead

I think this has been the biggest problem on the forums
No one has really gone out and done a BASE LINE map of the car before they started to modify the car.
As i have said numerous times before... Just because TOYOTAS racing dev team got lots of HP, doesnt mean you will as well.
Alot of the time it goes on tuning, the Air Fuel Ratios, what kind of Dyno it is and who the tuner is.

You have to keep in mind (talking round figures) Toyota made the 1g engine with 160hp - from the factory, ofcourse depending on the engine and what kind of life it has had.. it may have dropped, if your a lucky bugger.. then it could have gone up.

Even looking at the factory figures of 160HP with a drivetrain loss of 22% (RWD has more losses then FWD), we should be getting 125HP to the back wheels.

Now looking at Superchagers for the IS200.
They are belt driven.. = some loss of orginal HP made by the engine..
so if we say TOYOTA recommend 0.5 as a safe limit for this engine, and every 0.1bar is 10HP (round figures, probably more like 8hp) 0.5bar = 50hp.

So 160HP+50HP = 210HP /22% drivetrain loss.
=164 WHP.


- alot of time how much POWER the car makes is how the car is fuel'd
Ie running rich will cost you HP.. running lean could loose you HP but more importantly it is more likley to damage your engine.. = BOOM.

Melted pistons.. bent rods, cracked blocks, damaged deads.

I would get your car on an AFR or a wideband monitor and look and see how it is running, remmber closer to 12:1 = better.
to be honest the guys who run the dynos should have someone who can look at a graph and give you pointers.
If they dont.. I wouldnt use them..

Guys if you are going to ... go down TURBO or SC, get a good Tuner, the Dyno isnt that important.. the Tuner iswho will make your HP!


My example of the.. Bristol Dyno link was not to.. show how incorrect the dyno procedure, ( the page is really old )
But just to show..

"Your vehicle can be tested in one gear, or in all of its gears. Theoretically, the results should be the same regardless of what gear is used because the increased torque in the lower gears is cancelled by the decreased speeds. In the real world, there are always differences between the gears, and the differences can be explained by a number of factors. Because of nasty things like friction and inertia, different gears always have different amounts of drag, and the greater the reduction or increase in the gearbox, the greater the drag. A low gear may fly the engine through the rpm range so quickly that it never has a chance to build up any helpful intake and exhaust resonance that those header engineers spend so much time trying to achieve. Fifth gear may be spinning your drivetrain so quickly that significant increases in gearbox drag are created. Third and fourth gears are usually favorites for finding your actual horsepower, and testing all of the gears is a useful method for discovering problems in your drivetrain. Many dynamometer operators go right for the gear that is the closest to a 1:1 ratio as it has the lowest drag in the gearbox and therefore the highest horsepower reading (usually) on a vehicle that is properly sized to be tested on this dyno. Of course, many cars don't have true 1:1 gear ratios, and many cars are not the exact proper size that the dyno was designed for, so blindly going for the gear ratio that is closest to 1:1 is not always the right answer. My dyno is sized for vehicles that are around 3000 - 3500 lb. A significantly lighter vehicle, even though it may have the same horsepower as a larger vehicle, will probably have a final gear ratio that is higher. Therefore it will seem to struggle a lot more than a heavier car. In such cases, the lower gears, like third, may give the highest horsepower reading.
"

The answer to all that Jibberish is ...
Yes you can dyno in any gear
Yes You will make more HP in a lower gear, if the dyno is not calibrated correctly.

Ive said my babble this moring,

Ofcourse these are purly my views, if any body has a diffrence of views, or thinks I am wrong..
Please do correct me

No one has really gone out and done a BASE LINE map of the car before they started to modify the car.

I do that

IS200 supercharger makes 0.3 bar

cool.

So i guess you wont mind making a diffrent topic and showing a dyno for your is200
Please sir!



right so the standndard is 0.3bar, so people who are running higher "bar" are using a bigger pullie.
I know me and stav have been having a little chat about this, and his plans.

when i get it back i will indeed (mine is turbo'd) at .76 bar i'm told it produced 276 bhp

Would apreciate it

as have i

done a rr before i got any engine work done to the car and have one after. they werent done by the same people but i hope to go back to the origional dyno center to get the car retested

ah but did you have the Batman exhausts that time?