Help with dyno results

Hi all,

I had my car on the dyno today at Pod, and it looks like there may be a bit of a problem with it? I'm looking for any advice on what/where to look..

Basically, from what I can gather (well.. what I was told), there seems to be a problem with boost leak. Apparently, also, turbo 2 is coming online 400-600ish RPM too late, and there is a huge power drop between the two (more than double Millhouse's).

Turbo 1 comes online, and peaks at roughly 265 ft/lb torque, at just shy of 3000 rpm. The torque then falls to 220 @ 4000 (but starts dropping rapidly as soon as the peak is hit), then slowly starts to come back up with turbo 2. At 4489rpm, the toque peaks at 286.8 ft/lb.

Millhouse's results were overlaid on mine (he ran right before me), and not only did my power/torque peak nowhere near as high as him (he only has an exhaust from cat back, mine's fully stock jspec), but my drop is easily double his between turbos (and for much longer time).

Because I don't really know what I'm looking at, can somebody please hlep me interpret this properly, and give any feedback/thoughts they may have?

Thanks

The following is all the dyno pages I have. Bare with me, I don't have a scanner, a digital camera is going to have to do.

Edit: Since I don't think they give readings at the flywheel, wherever it says flywheel I think you can take it to mean rear wheels.. in fact, all measurements were taken at the rear wheels, despite the page heading.

Edit: The title of each page isn't clear, so..

Left hand side: Fly wheel torque graph

Right hand side: Fly wheel power graph

http://www.web-axis.net/~pulse/dyno/dyno2.jpg

Top: Vacuum/Boost pressure graph

Bottom: vacuum (mmHg - empty)

http://www.web-axis.net/~pulse/dyno/dyno3.jpg

Left hand side: Fly wheel torque graph

Right hand side: AFR Petrol

http://www.web-axis.net/~pulse/dyno/dyno4.jpg

Temperature graph:

http://www.web-axis.net/~pulse/dyno/dyno5.jpg

Thanks

-p

I had a boostleak to when I went for a dyno test. Check if all your hoses are still OK. One of mine had a hole in it!

This is the first time I have ever looked at Dyno graphs but I notice that your car runs lean at 4000RPM which is the same point at which your torque drops off.

Anyone of a technical nature, does this mean the fueling is dropping?

Th pressure in the turbo also dips at the same point, this having less airflow through the engine. If the right amount of fuel was going through the car at the point the turbo pressure dropped, wouldn't it run rich, and with a lower AFR?

I think my car displays the symptoms that Pulse's car shows in the graph.

Have you also got an induction kit on? Your inlet temps are much higher than mine were with the stock air box/filter.

The fuelling looks very similar to mine again all stock.

I also see that your only making 0.7 ish boost and then that's dropping off. I was making 0.9 with a HKS mid pipe and super dragger, and no boost control.

I figure your boost drop off is due to your inlet temps rocketing so much which may be a result of an induction kit with no cold air box / no cold air feed to induction kit. My temp graph is completely flat at about 65.2degs up to about 5,500 RPM if I remember rightly then it rises to about 67 over the last number of revs.

My car is completely stock J-spec except for the afforemention mid pipe and zorst, and was produced 321.0 BHP at about 5800 RPM with 305lb/ft torque at about 5100 RPM.

Hope that helps mate

Hey,

I don't have an induction kit, or any other mods.. my car is completely stock except for ICE and wheels. It still has the factory airbox around the factory induction (at least until later this week/early next week I think).

Would this possibly be caused by a duff intercooler or something? The boot to me seems quite low, both turbos running strong is only a fraction higher than just one turbo running.. that's been one of my main areas of concern.

That, and comparing the graph to Millhouse's, it looks like my 2nd turbo comes online quite a bit later than his (making the very pronounced drop in torque between the two).. if I put my foot down on the road, there's a very definite first turbo kick, then nothing at all, then the second turbo comes on with about the same force as the first (as shown in the graph).

So this all looks basically okay? Except the inlet temperatures which are all over the place for some reason...

Thanks

-p

Just comparing my results to Wipeout's (sorry Wipeout, I've stolen your picture:)), judging by his signature he has no mods ("No mods at the moment"), so I take it he's completely stock J-spec too.... as am I (no induction, no exhaust, no nothing).

You can see a massive difference in our graphs.. which looks more healthy? I seem to have a higher peak torque than him, but my graph is a lot sharper.. he has a higher peak power than me, and a more linear graph to get there.

Any thoughts?

Our power comparison (mine is the smaller picture)

http://www.web-axis.net/~pulse/dyno/wipeoutmepower.jpg

Our torque comparison (again, mine's the smaller one)

http://www.web-axis.net/~pulse/dyno/wipeoutmetorque.jpg

Any thoughts greatly appreciated...

-p

I think the circled glitch was a tiny misfire.

The other traces (runs) didn't show this effect.

The fact the trace goes lean at 4000rpm "I think" is due to the boost dropping off and the ECU removing fuel accordingly.

With the boost drop of corrected and the second turbo 500rpm lag fixed I think this will go away.

The pressure is the cause and the AFR the effect in my opinion.

NOT the other way around.

If the pressure was not dropping at the same time then I would agree it's a fueling problem, but not in this case.

Regards

Pete

Hello mate, Im a UK spec Manual, Dunno what sort of difference that may make but thought you should know.

Cheers

P.s. 2 of the three runs had the little glitch, the green one went higher and the blue one dipped, the red one was good but stopped shorter than the others.

if you want some more to compare with mine are uploaded here - UK spec auto with full decat, NuR and AVC-R. My runs were carried out at Thor's workshop.

Please note the dyno runs for mcanny runs are at three different boost levels. Stock 0.75, 1.0 and 1.2 bar.

Pete

Originally posted by Wipeout

Hello mate, Im a UK spec Manual, Dunno what sort of difference that may make but thought you should know.

Hmm 293 rwhp, have have you done to the car? Is it stock.. mine dyno'd 265 at the wheels when it was standard at G-Force.. and with 18% loss that was 323bhp.. which is about right.

It will be interesting to see the difference when I go in a couple of weeks.

It is 100% stock, it was running 0.82 PEAK bar boost on the day, i was supprised at the power output myself, i guess the drive train is at it's best with little losses. Not bad for a old thing!!!

Well, if we apply the same % losses to your results, it equates to about 345bhp! A little high for a stock car imho, but like I said, I'll reserve judgement until I get mine done on there

Originally posted by TRL Performance

Please note the dyno runs for mcanny runs are at three different boost levels. Stock 0.75, 1.0 and 1.2 bar.

 

Pete

Ah yes I'd forgotten about that!

Originally posted by Wipeout

It is 100% stock, it was running 0.82 PEAK bar boost on the day, i was supprised at the power output myself, i guess the drive train is at it's best with little losses. Not bad for a old thing!!!

i got 303 bhp @ 0.86 bar peak boost i was also surprised and very happy with the results

my supra is stock apart from the exhaust (both cats still in)