Dyno Results

[John_W]

I've decided that it's high time we had a thread devoted to dyno results, as I feel it would be useful if people shared dyno data.

Having fitted a large (2-1/4") exhaust to my car, I performed some dyno runs yesterday (http://www.wallaceperformance.co.uk/home.html) to acquire data to answer the question of whether or not a big exhaust is worth it. (I do notice a difference on the road.)

So far the only similar published data I know of is from Philbo (http://www.informatica.zen.co.uk/elan/Exhaust.htm) where he reports gains of 40 bhp and 30 lb/ft from fitting a Paul Matty exhaust (225 bhp from BBR + exhaust - http://www.asnu59.dsl.pipex.com/elan/gr ... torque.jpg). This compares with my own results of a 21 bhp & 11 lb-ft gain (215 bhp from an older V3 version of the Everest chip + exhaust), and more impressive gains when using the standard chip (because the exhaust induces overboost). I have not yet tested the latest Everest chip (V4.2), however I expect even more impressive results.<br><br>I performed two dyno passes, one with the standard and one with the (old version) Everest V3. Values are "at the flywheel", having performed "rundown" back to idle with the dyno and car free-wheeling to measure transmission losses. Results are displayed on the graphs:




I logged ElanScan during the dyno runs. It never ceases to amaze me how useful this brilliant piece of software is. Several interesting things showed up, as can be seen by the following annotated graph from the session.



http://www.asnu59.dsl.pipex.com/elan/gr ... _25feb.jpg

Some points to note are:

• The Everest boost goes up to 0.88 bar.
• The standard chip develops greater than standard boost owing to boost creep attributable to the 2-1/4" exhaust. Boost can be clearly seen increasing from the standard 0.6 up to 0.8 (then falling off). This shows that power can be increased by fitting a big exhaust (but only if you wait for the creep to take effect).
• Data I collected supported those collected by Philbo. The new exhaust was worth it:<br>Flywheel power with the standard chip was up from 155 @ 6000 RPM at the flywheel to 202 @ 7000 RPM (194 @ 6000 RPM). <br>Power from the V3 Everest was up from 194 @ 6000 RPM to 215 @ 7000 RPM (199 @ 6000 RPM). This seems like a big increase to me from just fitting an exhaust.
• The air/fuel mix at full throttle is way too rich (measured by a lamda sensor in the exhaust pipe). The dyno owner thought the car would benefit from some revision of fuel mapping, and I believe him.
• I was impressed by the dyno and workshop and will go back (to test the Everest V4.2).

I am still puzzling over the very high power and torque levels and over comparisons with my previous dyno run data and those collected from others. Once I've had a think and checked them, I'll post my conclusions.

I hope this has been useful and that you will all post your dyno results.

John  

[Sy V]

Do you mean compared to last time? if so...<br><br>Could the answer to the puzzle be ambient climate temp John?

[John_W]

[quote author=Sy link=board=upgrades;num=1109454348;start=0#1 date=02/26/05 at 23:41:49]Do you mean compared to last time? if so...<br>Could the answer to the puzzle be ambient climate temp John?[/quote]<br>Sy,<br>Yes, I do mean that I'm trying to reconcile the current dyno results with ones I took in August 2004 while I had my standard exhaust fitted. <br><br>You're right, part of the difference between them will be caused by the difference in air density between 16 dec C in August and 6 deg C in February. However another variable is the dyno used, and it's that which is causing me to puzzle. <br><br>In August I used a Sun dyno of the old style where "at the wheels" data points were acquired individually at each RPM station (10 data points from 2000-6500 RPM). It took time to rev to the desired RPM and maintain the rate while a reading was taken at each station. It also meant that substantial cooling time at idle had to be allowed between each data point.  Correction to "at the flywheel" values was done by applying an empirical 0.85 conversion factor.<br><br>On Friday I went to a 6-months-old state-of-the-art dyno where all data were acquired in a single continuous pass from idle to 7000 RPM. This was a very impressive piece of kit. It was computer controlled and (once calibrated to the Elan's RPM using the ElanScan values to avoid rev-counter inaccuracies) data were acquired very swiftly. Correction to flywheel values were performed by measuring transmission losses during a "freewheel" back to idle once 7000 RPM had been reached. <br><br>My intention was to avoid introducing this variable of different measurement systems by doing a calibration run with my current setup on the old Sun dyno. Unfortunately this establishment seems to have gone out of business, so I'm left with two independent datasets without any means of cross-calibration, which is exactly what I was trying to avoid.   <br><br>John  :-/

[Sy V]

To paraphrase in a more succinct form then.<br><br>Meaningless data provided by too many variables = Loada bollocks.<br><br> [smiley=moon.gif] [smiley=oops.gif] [smiley=thumbs_down.gif]... <br><br>My tongue is very much in cheek mate!

[Nige]

John,<br><br>Nice results.  Sounds as though the Dyno you were on is similar to the one I used last September, certainly the power runs were done as a single run after calibration and transmission losses calculated from a 'freewheel' back to idle.  Out of interest what were your at the wheels figures?  As you know from the results from me that you have, your standard chip figures are close to my Everest chip figures.<br><br>Nige  

[Sy V]

Oh Nige<br><br>Did you have to put a sensible perspective back on the thread?   <br><br>John<br><br>Keep at it mate.  Horizon used the "aiming at completing next week" phrase yesterday.  So with a bit of luck and a fair wind I'll be able to add even more variables soon.<br>The with Alan's "bespoke" Stripey chips, I'll have even more data, over which you are more than welcome to mull!

[John_W]

[quote author=Sy link=board=upgrades;num=1109454348;start=0#3 date=02/27/05 at 00:22:01]To paraphrase in a more succinct form then.<br>Meaningless data provided by too many variables = Loada bollocks.<br> [smiley=moon.gif] [smiley=oops.gif] [smiley=thumbs_down.gif]... <br>My tongue is very much in cheek mate![/quote]<br>Sy,<br>yes.... I can see I'll have to put this more simply for some readers.  [smiley=moon.gif]<br>Let's see...<br>How about "Fit an Everest chip and a big exhaust and the Elan can go like sh1t off a shovel"? <br><br>I'm hoping that by acquiring more datasets, I'll be able to make some sense out of things (hence why I've been begging dyno data from people recently). If there is something wierd with my earlier data (which I suspect may be the case at low revs, as Elanman alludes to) I might be able to normalise them given more information.<br><br>Good news that Stripey is near rebirth  :D. If you do any dyno runs, I'd recommend going for the modern computerised dyno, and having ElanScan running during the session. And most important of all, post the results in this thread. ::)<br><br>See you at Donington,<br><br>John  ;D  

[Nige]

Sy,<br><br>If I typed faster I'd have got my sensible post in before your loadsa bollocks!  ;)<br><br>Nige

[M100 TWO]

John W were you using a single drum dyno setup also what was your transmission losses in bhp<br><br>   john

[stevo]

i put missy on the rollers in standard trim a year or two back and the transmissoin loss was 12%. i have been planning and promissing( :-[) to do another one for months but i've not had the time or the dollar. :-/<br><br>the plan is to do one run with the chip in and one without, the differance that my custom 2.5" exhaust will make can be judged from my standard trim results from the other year.<br><br>i'll get there in the end, honest. ::)

[John_W]

[quote author=M100 TWO link=board=upgrades;num=1109454348;start=0#8 date=02/27/05 at 09:08:57]John W were you using a single drum dyno setup also what was your transmission losses in bhp<br>   john[/quote]<br>John,<br>I emailed the dyno owner to ask and received the reply below. I'm not completely satisfied with his reply and will have a chat with him next time I go to see what I can find out. <br><br>I'm maybe being simplistic here but I believe that if what you measure is at the wheels, then that's a number which should be reported as a "raw" figure in addition to the calculated or corrected figure in case you want to apply different corrections in future or even verify that the proper corrections have been applied.<br><br>I will also ask him for the diameter of the dyno wheel, how air pressure and temperature corrections are applied, and to which standard corrections are applied (BS , or SAE, or DIN or whatever).<br><br>Anyway, here's the reply:<br>This thing about power at the wheels is something I go through with everyone.  They all ask "what's my power at the wheels?"  The truth is, if I do the run in gear 2 the power at the wheels goes quite high but the transmission losses are a lot less but the flywheel power is the same regardless of the gear I use.  <br> <br>Also, as I showed you.  As the engine warmed up the power at the wheels went up (and would continue to go up) every time we did a run but yet the flywheel figure stayed pretty constant.  You cannot accurately measure wheel power due to all the variables in the engine hence we do not print this out.<br><br>We operate a twin roller system. I looked at a single roller system but they seemed very inaccurate + I could not get one for 4wd.<br><br><br>It's a Dastek dyno which was chosen for its 4-wheel drive abilities (http://www.dastek.co.za/ but it doesn't give many details). As you can imagine 4-wheel drive is very popular up here, and not just Land Rovers.<br><br>John   :-/

[Costas]

The most accurate by far Dyno machines especially for Whp are the ones that the wheels are screwed on it (steady) and not rolling on drums (?). The "Rolling ones" assume a power loss of about 10-15% and calculate the CHP and the WHP, not accurate at all and rather optimistic on results. The ones who have the wheels screwed on the Dyno machine are calculating EXACTLY the Whp with accuracy of over 99.5%. Just think of the difference of the braking (counter force) that a rolling Dyno can apply and what a steady screwed on wheels can. <br><br>I Dynoed the Sh4rk at his previous stage the same day at the same temperatures at 3 dyno machines. The 2 were rolling ones and 1 was steady one. <br>Results<br>R1 = 237hp<br>R2 = 235hp<br>S1 = 230hp and thats the real power I used to have.<br><br>I dont trust the rolling Dynos....<br><br>I know my tech Vocabulary is poor but I hope I made my point.<br><br>Costas

[John_W]

Aha!!!
here's the thread I was looking for. It was nowhere to be seen on the "Upgrades" menu, but I found it through the "search" function. Wierd.

Let's see if this little bump revives the thread and makes it visible on the Upgrades section.

[John_W]

Aha!!!
here's the thread.

Let's see if this little bump revives the thread and makes it visible on the Upgrades section.

YAY!!!

It worked. I have revived a thread . From nowhere to the top of the pile.

I have the POWER

John the computer-slayer

[robp]

just to keep it up there, i'll be taking mine along for a dyno run with an everest chip , and an unknown (alledgedly lotus racing) exhaust, some time in november. I dont have an elanscan cable at the moment, but am thinking it might be a plan. will then try again in the new year with a blueflame performance exhaust and manifold if they come up with one at the right price...

[delta]

Mine was tested 2 weeks ago.
Standard exhaust, cat and Everest chip. Dyno below shows HK ~ BHP, torque is in Nm. Don't know what that is in lb-ft. Do's somebody knows.?.

[John_W]

Delta,
thanks for the info. Your car seems to be going rather well.

If Hk is the same as the German PS, then your 185.1 PS power figure and 257.4 Nm torque translate to:
182.6 BHP @ 5571 RPM
189.8 lb-ft @ 4298 RPM.

My car gave the following figures when fitted with a standard exhaust and an Everest chip:
Peak power (flywheel) = 195 BHP @ 5500 RPM
Peak torque (flywheel) = 193 ft-lb @ 4000 RPM

Thus your power and torque are slightly down on what I found, probably attributable to your catalyst (mine is an SE with no catalysts). Your torque number in lb-ft is greater than the power figure in BHP, which is the other way round from any other results I've seen. Maybe that's a catalyst thing, or maybe my assumption of Hk=PS is wrong.

Now go and get a bigger exhaust and release another 15 BHP

John

[delta]

have just installed a 2½" stainless Steel exhaust, and looking forward to the next dyno........

[Doug]

[quote="John_W"
Now go and get a bigger exhaust and release another 15 BHP

John[/quote]

ah, John is a believer too :: spread the gospel my brother . . .