Dyno graph explained hellp
 

Abit of a newb in this area, I’ve had a previous Impreza on the rollers but was only really looking at the top end figure so was easy to see, I’m planning on taking the spec c in the next week to see what she is pushing and would like to know when I get the graphs what I’m looking at instead of a complete donkey.

Are power runs usually done in 3rd or 4th gear, I know the graph will have the torque and Bhp figures should there be anything else I’m asking for,
could someone please put up a graph of there pride and joy and give me a run down of what I’m looking at :) that would be really helpful.

Any advise would be greatly appreciated..

No clue how good this is but found it from a quick check on google
. might give you some basic knowledge

Power runs will normally be in 4th gear as this is closest to 1:1 drive.

They will do a few and put a few different graphs together. Normally flywheel power and torque on the same graph and flywheel power and turbo boost on another graph. The boost and power one is the most interesting as it will show you how fast boost is building and where it's at peak boost how early on in the rev range, which equates to turbo lag and driveability.

Here are a couple of mine in comparison from my old 2006 hawkeye WRX with STI TMIC, VF48 turbo, sports cat downpipe, 2.5" exhaust, 3 port, K&N panel filter and other basic supporting mods.

The hawk dual AVCS really helps spool. Mine was nearly at full boost by 3k rpm and was great to drive. My power tailed off slightly as the revs increased, but generally held very constant. Your old graph seems to build power more as the revs increase, which is good.

Also, I suspect your old car was a 2.0L wasn't it? the 2.5 makes much more torque than the 2.0L and much easier as you can see from my graph.

https://cimg8.ibsrv.net/gimg/www.sco...77dba54a14.jpg
https://cimg9.ibsrv.net/gimg/www.sco...3bc857e7bc.jpg

As an example of a bigger turbo with terrible lag see below:

This isn't hitting full boost until over 4500 rpm. That's mad. Will have no power through the majority of the rev range and feel horrible to drive in comparison.

https://cimg5.ibsrv.net/gimg/www.sco...c6f11d654c.jpg

Yes, mine made 334bhp and 381 lb/ft torque on it's 2.5. Was a blast to drive, always on the power with virtually no lag at all. Drove like it had a TD04 fitted but made bags more power and torque.

For dyno runs I wouldn't worry about weight at all. In fact if you remove weight it may promote wheel slip on the rollers.

It's probably not as bad as you think. Mine reached peak power at 4700 rpm similar to yours, but mine held while yours kept gaining. Would be interested to see a boost graph of yours.

One below is far more laggy if you look

https://cimg2.ibsrv.net/gimg/www.sco...81a24f6cfa.jpg

Does anyone actually drive below 3500 rpm when trying to make progress ?

Its also a Spec C so boost threshold will be nowhere near as high as that 400bhp Terzo, and the lag/transient responce when up there will be wayy les with the latest ballbearing turbo tech.

I have graphs of my car at 335 on a vf35 & 397 on my modded SC42@only1.5bar both on 2.0 sti Blob stock engine with bolt ons

Unfortunately no boost plot for the vf35 graph

VF35 Peak Torque = 332Ft/lbs@4840rpm, Peak power = 334bhp@6340rpm

SC42 Peak Torque = 362Ft/lbs@5460rpm, Peak power = 397bhp@6340rpm

Now that peak torque hitting 600rpm is misleading because it makes at least the same if not more than the VF35 did @ 4840rpm just went on to make more,

Peak power coming in at the exact same rpm too

What all these graphs fail to represent is the transient response, for example instead of flooring it at 2000rpm in 4th (Which is ridiculous really if trying to make progress)

Have em both sittin around 4k-4.5k then floor it (as you would in real world situation)

If you want a fast car at low rpm buy a diesel or direct injection Vag car that make peak torque around 2 grand lol,

Remember peaking early means it's downhill from there.....

Ask your wife/gf if peaking early is good......

https://cimg4.ibsrv.net/gimg/www.sco...d094a1e328.jpg
https://cimg5.ibsrv.net/gimg/www.sco...8c20080dbe.jpg

More graphs to compare,

Again same car, but this time using AFP road dyno software

The overlay with the VF-SC42 on v-power

Then overlay of V-power(426bhp) & 20% Ethanol (466)

Then 30% Ethanol 487bhp graph is on my thread sumwhere too

Take the road dyno figures with pinch of salt but the gains as a visual representation should be correct,

https://cimg5.ibsrv.net/gimg/www.sco...159dffe006.jpg
https://cimg6.ibsrv.net/gimg/www.sco...9989cf0ff0.jpg

Sorry to sidetrack a little but Smurf - correct me if i'm wrong here (its not easy being colourblind :lol1:) but when comparing the VF35 tto the SC42, the 42 doesnt actually out perform the VF35 until 4400rpm, is that right?

If you look at the first 2 of Smurfs graphs the VF35 made 120bhp at 3000 rpm and the SC42 made 200bhp at 3000rpm.

Thanks BPR! Thats the graph i was referring to. I was confusing the colours where they crossover.

Wait a minute... The 42 doesnt even make 100hp at 3k (second white graph)

Id rather compare torque if thats ok... comparing the two first (white background plots) from Ecotune. The VF35 makes just over 200lb/ft at 3000rpm but the SC42 only makes 175lb/ft at 3000rpm. at 4k the story is the same, the VF35 is out torqueing the SC42.

VF35 at 3k 4k 5k
200lb/ft, 325lb/ft and 330lb/ft

SC42 at 3k 4k 5k
175lb/ft, 260lb/ft 350lb/ft

Nice job. Looks very nice. Making around 1.6 bar of boost then and around 370 lb/ft torque. Result.

Great results! :clap:

A visit to Charlie at SRR ?? :)

Personally, i feel that below 4k even the VF35 is lifeless yes and the SC42 even more so, I'd say these 2.0 even when stock are not in their comfort zone below 4k. if you want to compare it with a good modern 300bhp 2.0 turbo

Torque is a lovely figure to throw around and compare but it is bhp @ often rpm's that make the progress

Compare the bhp at those points in the graph and you will see that yes it sounds good to have an extra 25ftlbs at 2k but in real world its a 115bhp car against a 95bhp car at that point and pretty useless either way.

Great to have in city driving tho, so your car is not constantly screaming its head off,

The turbo on my car is also only just getting started 427@ 1.5bar so had alot more to give on v-power if wasn't strapped to a stock engine.

or just up the idle to 2000rpm and stay away from the dead zone,

AFP graphs are best comparison as data is taken from real world driving not in a dyno,

Would be nice to see my turbo on a 2.5 tho always been curious as to what that extra 25% capacity would do for it

Smurf, thanks for the reply. I totally understand your points regarding lower to mid range, you're dead right its up top where the magic happens. Whats been modded on your 42 if you dont mind me asking?

Lee - is your Spec C standard?!

Great results,

Is your car a twin scroll, and would it not rev till 8k if you wanted it too as well ?

https://www.scoobynet.com/subaru-par...let-turbo.html

The link to the thread i bought i from on here,

Bigger Billet wheel & some other upgrades, metal caged bearing etc.

When i contacted Owens they says it was a 76HTA wheel trimmed to 73 & the Exhaust housing was an 8cm one.

Isn't the Blouch Dominator XT1.5 that the SC42 is based on an 8cm housing from them as standard? They fit the 7cm for ScoobyClinic only don't they?

I'd certainly be up for doing something like this to my SC42 when it needs a referb.

Yea strange, i wasn't too fussed when i found out,

Technically it's not even an "SC" if no 7cm housing,

I believe the cost for the Owens work was around £600

I got a great deal for it off here

I know it's the older design without the black housing, but considering the work that was done by Owens and it's essentially a brand new bespoke turbo somewhere between the SC42+ and SC46 now with that spec you got a great deal from Rich. I'd have snapped that up if I was looking at the time. :thumb:

Also, I don't think £600 is that bad to be honest. I'll certainly contact them when mine needs doing.

Yea they had to machine the housing anyhow, really its just a pretty cover although i would say the black ones look better imo,

Yea going by Owens terminology it's now an ODGT30/73HTA-M,

Only M-Spec parts missing are the pointy nut because it's not a v-band

I was over the moon to find it, i drove from Glasgow to collect haha

hahaha. That's a long way Smurf. I live half hour away from Rich and have to drive to Glasgow for work now and again, that's a long days driving for a turbo. lol. Worth it though.

I didn't realise Blouch used Garret cores to be honest, just assumed they had their own range. My SC42 is the newer black housing design and it's got Garret stamped on the cartridge. Will have to check the part numbers to work out the spec. Suspect mine still has the PTFE bearing carriers, so will upgrade like your eventually. I've gotta get the thing fitted first and a few miles under it's belt before I upgrade it.