The 1st graph in question was set up on a roller tacho not an inductive pick up for convienience only. Diddy did not pay me for any set up, just to check boost pressure not to check at what rpm it was peaking at or any flywheel torque figures. As metioned earlier tacho in not required for an accurate flywheel BHP or AFR figure on Dyno Dynamics 450DS. So if the roller tacho seems to be high it was not crucial to the checks that we were making. Obviously if you were paying for a full check, Mapping session or diagnosing any problems with boost etc then an ignition inductive pick up will be used.
Hope this clears up your issue with the graph.

IMHO getting an injector pick is rather easy, especially on a Fiat Coupé and from a business point of view it should be included to give a more accurate print-out and of course to give your customer(s) more detail.

Hi an engine tacho is not needed when you are stricly focusing on doing power runs & shootout days, If you were having a full set up or mapping session then a ignition inductive pick up will be used.
Hope this clears up your issue.
Will try the inj pick up as said.

Ok Vas so my second graph is wrong...why?

It was done on a shootout day with many other cars all producing the rough correct bhp for their given car and mods including mine.

My car runs a Dinks map, correct, redline according to my car is 6800rpm on my tacho. YES we are aware the revs were out on the first set of runs as THE CAR WOULD NOT GIVE A STRONG PICK UP it kept fluctuating. However, seeing as my car runs a Dinks map with all breathing mods and boost setup to the map the power figure IS correct as that's what Dinks mapped it for.

PLUS when the car was first run it had a stock exhaust with silencers still in and a gutted cat and on Saturdays shootout the exhaust is now straight through with straight through pipe work and produced 5bhp more which is roughly what should happen!

I'm aware the 1st graph isn't spot on due to the revs being out BUT I wanted to see boost pressure and fuelling and power...NOT revs. I chose to have those checked and they were done and from what I've witnessed and been told from Bob the dyno is accurate and has been setup properly.

The car is running a stock turbo but as we all know (if you've driven a 16vt) the boost comes in, in one hard hit as apposed to nicely and progressively, well it does one mine for definite and the graphs show that!

If you wish to continue debating whether my car is as powerful as the dyno makes out or if Bob's 2008 Dyno Dynamic Rollers are wrong Bob is willing to offer one of you to come down and have your car run for free to prove he knows what he's talking about.

IMO the power figure is correct regardless of what the first graph looks like and it shows the increase with a straight through exhaust.

Rant over.

i don't think anybody questioned the power figure???

Well I just figured seeing as the whole graph has been pointed out to be innaccurate I therefore assume that also means people think the power figure's innaccurate too?

Well said Diddy. The flywheel power will stay the same regardless of whether the dyno is run in MPH across the axis or if Engine RPM or Roller tacho is set up....

Hope thats cleared that up now!!

i dont think people are attacking you (diddy) or bob, i certainly wasn't, it's just i hav'nt seen a graph done like that & just wanted to know why

just pointed a few things I know are true regarding the first graph (the one with revs). So technically I should have used singular and not plural since I'm refering to the first one, apologies on that!

Being 3K miles away I cannot know nor I care how much power this particular engine is producing. However, from past experience it looks OK from other graphs I've seen and chips I've used on normal (bar exhaust) 16vts.
OTOH, if the first go is off, I could question the second.

over and out

V.

Nobody is doubting the figure, or Bob's ability, but as has been discussed many times before you can't compare different rolling road manufacturers as they *will* give different results* so you might find that no-on will take him/you up on that offer.

*I won't get drawn into which are the most accurate.

Hope this issue is now settled....

I'll say it again, a dyno (ANY DYNO) measures Torque at the wheels. It then uses this torque figure and the rpm of the vehicle to calculate the BHP at the wheels and applies a % loss onto this to give you an estimated bhp@ flywheel figure.

BHP= (Torque*rpm)/5252

If you don't have torque at the wheels AND rpm, then you cannot calculate the BHP. BHP isn't a figure that can be measured on a dyno. No dyno will bring it back accurately without the rpm and torque. Get yourself a torque vs rpm print out and I'll tell you what power you're making.

Another thing, this road speed issue. Why does it go from 23mph to just over 84mph? In third gear (which is the wrong gear on a dyno anyway), this is 2,240rpm up to 5,600rpm and would suggest that you are making peak power at 4,300rpm.

I'm sorry Did and Bob, it's all just wrong

Sorry but do you own a 2008 Dyno Dynamics Dyno????
If not then i suggest you go to the Dyno Dynamics website & contact the U.K rep Mike gurney & express your issues to him.. Obviously as you know all dyno's & software are different. But if your an expert on dyno's which i doubt if you don't actually own one, then talk the Mike the U.K rep.
I'm sure he will put you straight as you dont't listen to anyone & as you know everything about Dyno's

Bob, I don't claim to be an expert on dynos and I certainly don't own one, but I like to think I can spot a poor print out. Here are the facts that lead me to believe that it isn't accurate.

-Rev limit is out on graph 1 (7,600rpm). The rev limit on Did's car will be under 7,000rpm. This will result in higher BHP results. Plot the actual torque on the same graph and we'll see how...

-Speed axis doesn't correlate to third gear on a Coupe and indicates peak power at 4,300rpm on graph 2. It should be nearer 5,700rpm.

-Peak Boost comes in at 5,250rpm on graph 1. It should be around 3,400rpm on a 16vT and should be even earlier if he's running an aftermarket boost controller.

-The second graph shows a higher peak power, but it trails off to 200bhp where the first graph made a consistant (and more normal looking curve) 220bhp to the redline.

I've taken the liberty of putting the figures from graph 1 onto an excel spreadsheet and using the forumla to work out the torque with an rpm correction and it is still suggesting that peak torque is made at 4,600-5,000rpm which a 16vT simply will not do (at this level of tune anyway)

If Did is happy with his figures then there really is no problem, all I'm saying is that I wouldn't be. Until I saw a torque vs rpm plot showing a redline of 6,900rpm along with a Torque curve peaking at around 3,500rpm, then I wouldn't be happy with it.

I'll also note that since my previous post I have been corrected and now know that there are in fact inertia dynos that can calculate BHP without needing to measure torque so I apologise for that statement. I listened and learned something there!

If you look back through this post.. An inductive pick up wasn't used for convienience only we was not setting up diddys car only checking BHP which as you are now aware dosen't need rpm, So BHP figure is correct.
We was only checking how much boost we was running on the car not at which point peak boost was or at which point peak power was. There are many graphs out there but this 2008 Dyno Dynamics software & Dyno is state of the art & doesn't need RPM or Torque to equate BHP...
The roller tacho was used on this run & as i said before was for convienience only, we was not setting up the car or mapping it in any way. I seem to be repeating myself over & over again. If you still have issues with this graph & is not to your standard then so be it. BHP & BOOST pressure was all we was checking & those figures are correct...
I won't go into too much detail on my dyno cause know it alls tend not too understand the 2008 software & i will be here for ages. Got a dyno run to do know hope this next graph is up to your standards...
If you have never owned a dyno or had training on a dyno then you are just playing with figures that mean not a lot
Call Mike Gurney of Dyno Dynamics if you have anymore issues
I'm sure he will put you straight. I'm not a fiat no it all nor wish to be, but i know my dyno. END OF ISSUE

Fair enough, this has gone on for a while but I'll explain my angle one last time so you see where I'm coming from.

I had a dyno run at RedlineTuning in basildon by a guy called Richard on a dyno dynamics machine. The power was grossly overrated at 277bhp, 238lbs/ft and the redline was over 800rpm over what the car could do. After getting a custom chip fitted (not fully mapped I should note) the car made 18lbs/ft more torque but 15bhp less (262bhp, 256lbs/ft). By putting both of the torque curves on the same axis on an excel graph I could clearly see that the original bhp figure was only 254bhp. Consequently, I don't rate this shoot-out mode very well...



Post it up and I'll take a look

A Dyno Dynamics rolling road give grossly overrated figures?

Surely not.

I've had more than 1 car Rolling Roaded on Dyno Dynamics rollers on the older software and they tend to under-read rather than over-read or be pretty accurate.

Matty why not come on down and run your car on Bobs Dyno. Maybe you haven't got 415bhp afterall. Your figure must be wrong coz I said so.

Sound familiar?

Do you really think Matty is going to drive all the way down from Scotland to the South of England to test a dyno, when he has permanent access to Wallace Performance Dyno?

I don't think putting another coop on there would prove its accuracy. Indeed I'd expect it to be different to my last run, but I would like to see two runs on the same car, one with rpms measured accurately, and the other one of these shoot-outs that measures bhp directly.

No is he heck, the air is too warm!

I'll see if Bob will do it with my car again soon then!

I'm pretty sure the figure is correct and the dyno is accurate so I'll gladly put it to the test again

If you look at my post it contained a in it.

Pah!

Last time the ambient temperature was around 17 degrees....perhaps I'll run her again now it's proper cold.

hm, I thought 17 degrees is proper cold, no?

17 degrees celsius is roasting in Aberdeen Vas!