Butty

iTrader: (2)

It can do

Banny - has that cone got a cold air duct feeding it?
I see your IT is only 2 deg higher than AT.

banny sti

iTrader: (68)

Yes it has a pipe running up to the air filter

Matty WRX

Now that would be nice! maybe then I'd not get the continual spanking from my local EVO bud!!!

sc_sjo

iTrader: (7)

If you're that desperate to get accurate figures (for why I really do not know) then put your engine on a controlled-environment engine dyno*.. perhaps if it comes within 5% of your rolling road numbers the nay-sayers could share the dyno costs between them

I wonder if anyone on either side of the fence is willing to put their money where their mouth is though......





* Yes, I know this still uses temperature compensation which can be fudged, but it allows repeatable tests and *if* used correctly, accurate numbers assuming the equipment is calibrated.

dynamix

iTrader: (3)

On a DD dyno the easy fudge to get high figures is to move the IT sensor (if it has one) closer to a heat source. The gap between AT and IT seems very high and could be 'over correcting' the figures.

Barometric pressure also seems high and this has an impact on the results but I am not sure which direction ..

AbbasSTI

iTrader: (37)

If I put a heater next to my air filter would it give me more ponies?
I've been on the look out for a good CAI kit, but now I am looking for a HAI kit

TonyBurns

iTrader: (3)

It could be, or the airflow in the engine bay is really bad, or the sensor is duff etc
I would go to a different rolling road (same type), see if the issue of the IT/AT is still there, but as I dont use dd rolling roads (bosch for me), its all corrected anyway, showing peng/ploss/pcorr etc.

Tony

Adam K

To all of those who is confused about the RR or any stationary torque-reader.
From what I've gathered here and earlier.
The RR or hub-reader (essentially a generator or a hydraulic motor) reads a torque. It simultaniously reads other factors, like IT, AT, some read rpm, etc. All this goes in to a computer who calculates, or fit these values into a table, to compensate for all variables of this particular power run and make the reading comparable to a run on another day, or with different tyres (RR's), etc. The computer then shows a calculated power figure.
I have experience of Rototest kits, 2 different ones, and on these you can get the figures before any calcuations, ie the hub-power. Even though the 2 ones I've seen both are Rototest, the operators came to very different conclutions regarding the engine power output (opinions on transmission losses being most important)

Now...
'D's outputs are to a fraction of a hp the same, this kind of proves that the RR computer comensates the values before it shows them, otherwise the result would be quite different. On the other hand it also shows that the calculations are quite good, since it's the same car, with the same setup, and should show a very similar figure.
So the result is already compensated! To whatever the system is programmed to, DIN or whatever.

I was convinced that 'D' would have gone to a different RR or hub-reader to get a 'second opinion', and is a bit surprised he didn't. The computer conclusion is higher than I have ever heard of a vf35 giving, and I would like to see readouts from the same RR on som other cars, preferably some stock STi's to get a feeling of how that particular RR is reading, generally.
I think it's a very capable output from a vf35 anyway and want to congratulate 'D' on a good job, be it 360 engine hp's or 380.

Edit: missed last inputs form last night and those from this morning, looks like what I wrote has been explained already

Tidgy

heres a list of the readings,

AT = Ambient temperature
IT = inlet temperature
RT = reference temperature
RH = reference humidity
RP = reference pressure
TN = inertia setting
RR = ramp angle
PL = power loading
CK = check reference

scooby-tc

iTrader: (2)

You should try it on Surrey Rolling road,Charlie knows all there is to know about DD rollers and you will get a far more accurate reading as Len is still learning how to use his rollers as they have only been in a few months

Big 'D'

I assure you the figures shown are not fudged in any way, the BP is perfectly normal too.

My IT, taken from the intake filter on the side of the filter furthest from any heat source. The crap design of my intake heatshield offers no protection from engine heat infact it creates a low pressure area compared to the main engine bay whilst there is air blowing into the front of the car, be it a dyno fan or forward motion on the road, due to this low pressure area hot air is actually attracted to my filter so the high IT is correct as it is my actual intake temp (FACT), the only reason the IT was lower on this run than the last one is due to Len kindly removing the rubber weather strip from above my drivers side headlight which allowed some of the fans cooling air to get directly to the filter.

The IT is correct

The AT is correct

The BP is correct

And the figures shown are corrected.

Out of interest to those who still doubt the IT AT figures, we ran the car with the intake temp sensor outside of the car so very close to the AT approx 3 deg higher (sensor was placed on the bonnet release catch), the car then ran approx 10bhp down on the graph, I think that this proves that by telling the dyno that my IT is 19deg when it is actually 33deg that the overall power shown will be lower, the opposite of having an IT of 17 and sticking the sensor somewhere hot and getting a higher figure. My IT is taken from the same place everyone elses is, from the intake so forget about the IT AT figures please.

Cheers Iain

Big 'D'

Without meaning to sound rude, can you please explain to me what they would do differently and why the DD rollers at Surrey would be more accurate?

Have DD made the system so complicated that Len cannot understand what he is doing? (I doubt that), I think its more of the fact that he has not had the Dyno in for that long by comparison to many other places, but like I said before I could get 10 different dyno readings from various different locations and even if they were all within 10bhp the figures would still be fudged in some way so I dont see the point really.

I have gone back and had a re run at the same dyno and all the parameters are correct and it ran to within 0.1bhp of what it did last time and I am pretty sure that my car is not the only one that has been on the rollers in the past 7 days so are all their figures incorrect too?

Cheers Iain

Big 'D'

No there is no disparity, because my intake temp were actually 33 and 42 deg with the same car on the same rollers a week apart the power made was within 0.1bhp showing that so long as the IT is actually taken at the intake and not in a pot of boiling water the corrected figures should be the same and they were, and regards the boost it only spiked to 1.5 bar not ran at 1.5 bar. The overall boost pressure was pretty much the same as before.

Cheers Iain

TonyBurns

iTrader: (3)

Its the fact you ran .1 bhp difference, remember your AT/IT changed from the original and your boost was higher on yesterdays run, so its either very coincidental or you need to run the car somewhere else tbh.

Tony

PS, best if you post both sets of prints up in the same post
Still good figures even if they "may" not be correct

Big 'D'

Yes my IT/AT has changed but the overall output did not hence I am saying that the figures shown are corrected (not fudged) and my car only spiked to 1.5 bar not ran at 1.5 Bar.

From what I understand from all this,

As my IT last week was 42deg and the output was corrected to show 382.8 my IT could have been 17deg yesterday and the corrected output should have also been close to 382, so I cant see the issue with the figures anymore.

Cheers Iain

scooby-tc

iTrader: (2)

Because SRR is solely a dyno no other distractions and Charlie has been operating the rollers for years and years and has vast experience on loading settings etc whereas the dyno at S4U has only been in 8 months or so and Len is still learning about the setting up procedure (although he is doing very well)

For example when JollyGreenMonster mapped my Spec C on the rollers at SRR it made exactly what is should have with the mods i had which was 360bhp/370lbft at S4u it jumped to 367/396 due to the graph being incorrectly setup before the run.If i can find my figures from S4U i will post them for people to comment on

Still very good consistent numbers though

scooby-tc

iTrader: (2)

ok i was wrong about my figures,shows how long ago it was

Here is the graph from Surrey Rolling road which i believe to be more accurate



and here is the one from S4U,notice the jump in torque



this was purely down to incorrect setting up of the rollers and we were offered a free rerun but i sold the car shortly afterwards

This is in no way a dig at you or your figures its purely to show the difference between 2 sets of identical rollers with different operators

TonyBurns

iTrader: (3)

Daz, interesting that SRR printout has a 2 difference on the IT/AT yet on S4 U its much further out, ie 8, and its run in 3rd gear again (6 speed box)

Iain, I would take the car to SRR, i think you will get a more accurate RR reading there

Tony

Butty

iTrader: (2)

Iain,
What is coming out of this is that a ducted air feed is needed on to the air filter to give a lower IT.
Presuming the negative pressure area still exists when on the road, the air feed will give you 10hpish more actual power but ironically drop any future rolling road figure by 10 hp next time you run one.

The question is do you want a headline figure or better drag times?

MarkC

iTrader: (12)

Its a pity you didnt get it done somewhere else, of course when you go back to the same place you will get around the same figure. they are not going to tell you your car is making for example 350-360 bhp, when you only got it done already recently, so they will give you the same result.

Big 'D'

The bhp on the 2 graphs above are only 2 bhp out regardless of the incorrect torque figures. I was asked to go back to Len and re-run at S4U so I did, if I lower my intake temp to close to AT my overall Bhp should not change much if I am understanding this correction properly, so regardless of my IT being 42 or 16 so long as the AT and other conditions are close to what I did my first run the power should be the same here or there.

My run was done with the bonnet shut on both occasions, perhaps that is why there is a difference in IT/AT on the graphs just posted up, did Surrey have the bonnet open or closed?

Cheers Iain

dynamix

iTrader: (3)

It is the IT that the DD sees that affects how much correction is put in.

scooby-tc

iTrader: (2)

Bonnet was closed (i think,can't really remember) at Surrey,and the graphs may only be 2bhp different but as you can see the S4U one was run in the wrong gear and the rpm on the graph was also incorrect resulting in inflated figures.It was just an illustration to show how different rollers/operators can affect results

Big 'D'

So is the following correct or not: Scenario -

1st run (true IT reading) 42 deg AT 14 deg corrected power output = 382

2nd run (true IT reading) 16 deg AT 14 deg corrected power output = 382

3rd run (false IT reading) 16 deg (true IT 44 deg) AT 14 deg corrected power output = less than 382

4th run (false IT reading) 44 deg (true IT 16 deg) AT 14 deg corrected power output = more than 382


Cheers Iain

Lewak

iTrader: (1)

Iain. i would just given in on these lot. They don't believe you and its a just a waste of your own money going to different RR places to get a results (UNLESS YOU LOT ARE WILLING TO PAY FOR IT).

Two runs both with in 0.1bhp of the last
IT and AT are true
BHP true


good enough for me


know who wants to take this to court and let them decide as thats what its seems like needs to happen.

Cheers

Dave

Lewak

iTrader: (1)

Iain. i would just given in on these lot. They don't believe you and its a just a waste of your own money going to different RR places to get a results (UNLESS YOU LOT ARE WILLING TO PAY FOR IT).

Two runs both with in 0.1bhp of the last
IT and AT are true
BHP true


good enough for me


know who wants to take this to court and let them decide as thats what its seems like needs to happen.

Cheers

Dave

Big 'D'

I dont see why I should back down as the whole thing has just boiled down to my word against theirs, end of there is no real dispute here, if my car had run 355.8 and 355.9 respectively no-one would have batted an eyelid but as soon as I throw a 380+ in the mixer, NO, NOT POSSIBLE, FIGURES FUDGED etc etc.

My car does what it says on the tin, the end.

Cheers Iain

TonyBurns

iTrader: (3)

Its not true though, can you not understand that?
Lower IT on the one yesterday, higher one on the previous, yet still very similar, not really consistant tbh, and the fact is that S4U seem to always have (by the look of daz's graph also) highly inconsistant AT/IT's, which will give misleading readings, hence take it to SRR whom lots have used for RR days and has a very competent operator who has used the DD type RR for years and has lots of experience with said RR.

Tony

banny sti

iTrader: (68)

Thought I would brighten the thread up with some more graphs

Tidgy

these ones actualy look like they may hold water,,,,,,,,, pmsl