Hypertech Dyno Vids, Pics and Discussion

Post by **Merlin** » Mon Nov 25, 2013 9:00 am

Yeah the Focus sounds awful

Every Prelude there had an aftermarket exhaust on it, all the 4ths had aftermarket manifolds too. That could be a reason why they sound so good.

All the Preludes got something beneficial out of the dyno so it wasn't a waste of cash.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Mon Nov 25, 2013 10:50 am

Don't know about how different dyno's work etc but does the dyno rely on them selecting the correct (matched to the car) gear ratio in the dyno software or something?

If so, do your printouts show what that was set to while the ludes were on it? Was it right?

Post by **Merlin** » Mon Nov 25, 2013 10:56 am

It was run in 4th gear and the dyno knew it was 4th gear. However if the dyno has the 4th gear ratio set wrong it will bugger up the calculations. All dyno's read the power at the wheels and some calculate it back up to the flywheel.

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Mon Nov 25, 2013 11:00 am

So the dyno says 4th gear, but doesn't show the actual ratio?

Out of interest, with what you've done to the gearbox, has that changed the (compound of 4th+final drive) ratio significantly from what the other ludes would have been running?

Post by **Merlin** » Mon Nov 25, 2013 11:12 am

Merlin wrote:Out of interest, with what you've done to the gearbox, has that changed the (compound of 4th+final drive) ratio significantly from what the other ludes would have been running?

Yeah my gearbox makes a huge difference. Due to its shorter final drive. I have a shorter 5th gear too in comparison.

Apparently the shorter the gear ratio / final drive the lower the dyno will read your wheel hp at. No modifications to the dyno were made to take into account and gearing differences I have compared to the other Ludes.

macky_6 · Post by **macky_6** » Mon Nov 25, 2013 9:53 pm

Was a bit miffed with the results

Basically nobody has any idea what kind of power we are putting out

We only know where we are relative to each other.

I thought the whole point of a dyno was to give some kind of accurate number? Giving a total of nearly 40bhp below the actual reading isn't very accurate in my eyes

Kind of made the whole day pointless

I guess if you were using it as a starting point and then making some mods it would make sense? I know that when this happens i won't be going back here for the results

was good to see everybody out though and if nothing else, the Ludes all sounded brilliant on their runs

Also, we were all made aware of some issues with our cars regarding overfuelling etc so it wasn't all in vain

89 UKDM BA4 4WS (resto job!) · Post by **wurlycorner** » Tue Nov 26, 2013 7:58 am

Ooooh, intriguing, what was this about overfuelling?

Post by **Merlin** » Tue Nov 26, 2013 9:02 am

If you are too rich you will be down on power.

I have looked a the sheets in detail and I can see that the dyno is not reading torque properly over 5K or so. The torque curves do not increase after VTEC, are not as sustained as other dyno results and fall off very quickly. On other dyno's torque hardly dips until after 7K. On this dyno it show my torque dropping off after 6500, Macky 5750, Andy 5250, and newkid 5750. To say that a VTEC engine doesn't produce more torque once VTEC kicks in (Yo) is bullshit. Your arse dyno tells you that isnt true. The rate of acceleration is much more in VTEC than out of VTEC and that is purely down to torque. After looking on the net a bit more it seems that this is a common issue with the DynoDynamics, not reading torque properly over 5K ish.

I compared my graph with the one from Dino's last dyno and were matched each other (almost to the exact torque/bhp) until 4500rpm. After that the DynoDynamics dyno screwed it up.

Like I said before I think all Luders got something beneficial out of the day but only because 5 of us were there.

NCCMUR · Post by **NCCMUR** » Tue Nov 26, 2013 9:12 am

Regarding the overfuelling
Is this controlled by the o2 sensor?
Or how else can you reduce the fuelling?
Just that mine is noticably stinkin of petrol when running but i know i still have to replace the o2 sensor will this help?

Post by **Merlin** » Tue Nov 26, 2013 9:16 am

Fuelling and having too much fuel in the exhaust gas is controlled and can be influenced by a multitude of things. Off the top of my head (but the service manual will tell you more):

O2
TPS
MAP sensor
IAT sensor
Engine water temp sensor
Ignition timing
ECU