silent running

I'm not that hung up on numbers as my Scoob is plenty fast enough on the road, which is where it was mapped on a Power FC with a TD05-16 @1.45 bar with all supporting mods incl FMIC. However, having not taken it on the rollers for a couple of years, a run this morning at a new Dastek dyno cell in Norwich produced wheel figure of 244.3 bhp @ 6095 rpm and engine figure of 291.3 bhp @ 6154 rpm. Maximum torque is apparently 277.1 lbft@ 4641 rpm.

Now, even though I'm not too troubled by a few horsepower here and there, and understand pretty well how unreliable dynos and comparisons can be, I was hoping for 300+. It's just a psychological barrier for me really. My last car I tuned from 130bhp to 235bhp, now I want to move my Scoob from 235 to 300+. It feels fast enough for it for sure.

So my question is, do these sort of figures sound about right (to my mind a TD05 blowing at 1.45 bar should be producing more power out of a 2.0) and does the flywheel vs. wheels relationship stack up. Seems like a fairly healthy wheels figure and I'm wondering if the trans loss is a little underestimated. But I have no-one else's figures to compare with. With my Science head on, I can't see how the same power run can produce a peak figure at different rpm for engine vs. wheels power. Surely if the trans loss is 'calculated' with any accuracy the peaks should be at exactly the same point because the source of the power is the same - the engine.

The wild card is that it was mapped for V-Power but every now and again I run a tank of normal Shell unleaded, which I did this week forgetting I was up for a power run this morning! Anyway, I was running a mix of 2/3 unleaded, 1/3 V-Power and a bottle of Millers Octane Plus. Det was well under control as far as I could tell and I can't see how this would effect the power run as the Power FC map would stay the same regardless of fuel.

All opinions welcome!

exvaux

iTrader: (1)

Numbers seem ok and if your happy with the power on the road then alls good.A lot of folk get hung up chasing numbers on a dyno,the "psychological barrier" as you call it,as long as it drives well thats the most important thing

silent running

Yes it does drive well and it's as fast as it needs to be on the road although perhaps could do with a little more on track. I'm just surprised that it doesn't seem to fit with the usual estimates of an easy 300+bhp for a TD05-16G worked fairly hard.

rigga

iTrader: (4)

Have you read carl davey's thread from a while back regarding the same subject?.... it was not as easy as many say to get 300, and my car made 288 when it was last run up...... strange some do it easy and others not so,again dyno differences may account for a little.

https://www.scoobynet.com/projects-4...ty-budget.html

rentonone

iTrader: (1)

i personally think it should be more like 330bhp running that much boost judging by what i have read on here. I was running 1.3 bar on a vf35 and that produced 310 bhp. (my 99 uk)

James

fireblade37

iTrader: (1)

Bob mapped my00 16g front mount etc, it made 321bhp. 324 ft lbs, air temp 24 deg C. that was measured on the road. Put it on the rollers last week and gained 12bhp 5ft lbs, 10 deg c. Boost 1.4 peak. Your figures do seem a little low but thats rr for ya. Was it making 1.45 on the rollers?

Herbie.

I had 340/325 on my 16G running a large topmount and other supporting mods at 18 psi.

andythejock01wrx

Silent,

I have an 01 WRX with an Andy F TD04 hybrid. I had it rolling roaded at at Dastek in Fife. The figures were 258bhp atw and 301bhp at the fly. I too expected a little bit more, but understand that Dastek is one of the more "authentic" (ie lower reading) systems - one way to think of it is that you could have easily taken the car to a RR which provides more optimistic figures (but then what would be the point in that ?).

IMHO, you have to take these figures with a pinch of salt. If two cars have been taken to two different RRs on different days and are only, say, 20 bhp apart, they really can't be separated (unless you drive them both).

HTH,

Andy Mc

silent running

Could there be any effect of it being mapped in the height of summer and today running it in something like 6 degrees of ambient temperature? The lambda up the tailpipe showed that it was running a little lean at full load. Although I'd thought that a slight richening of the mix would only run safer not more powerful.

ZEN Performance

Power seems a little low, but remember it will be corrected relative to the temperature, so the actual power measured will be greater (assuming the ambient temp was about 8ºC. The power peaks for wheel and flywheel power will not be the same, as the losses are a greater percentage at higher RPM than at lower RPM. If you have a flat power curve from 6000 to 7000rpm at the fly wheel, but losses are increasing (with road speed) from 6000 to 7000rpm, your power at the wheels will drop after 6000rpm.

As for fuel types, I would expect the coctail to be representative of good fuel, and if det was avoided the power should be about right. The engine itself has a big impact on available power from a given set of mods, so things like good ring seal, valve seating, and actual compression ratio shouldn't be ignored.

Your car is mapped to retard the ignition in the event of significantly increased induction temps (at the throttle body) but that will only come into play over about 30ºC.

Paul

New_scooby_04

iTrader: (4)

The infinitely more knowledgable Paul has beaten me to it, but I was going to ask what mileage you're on; e.g. you cant expect an engine that's seen 80,000 miles to produce the same figures as one that's done 20k.

Could just be an artifact of the RR set up - if you're happy with it on the road, that's all that matters.

Ns04

ZEN Performance

It's an engine of "questionable" origin I beleive.

silent running

So sounds like nothing to worry about then. The car has done 128k but the engine only around 10k of those since a rebuild by a new (at the time) local firm who talked a good game until they went bust - who I used before I knew of any more reputable alternatives. I know the 'STi' heads they fitted when the first ones seized were actually WRX now, so who knows whether their ACL bearings and Cometic head gaskets were just Unipart. The engine does work though so that's the main thing although the problems I've had with surge were possibly down to inefficiencies in the engine too. But I doubt charge temp will have been a problem at all, it was a good dyno cell and they positioned the massive fan ducting right in front of the FMIC.

There is a correction factor of 97.1% showing on the plot at 6.5C ambient temp and 1010mBar pressure. Looking at the separate plots is quite useful. Flywheel power and wheel power show a fairly sharp ramp up from around 2700 to 3000 then a slight flattening for a couple of hundred rpm then a nice tidy curve up from 3200 all the way through to around 6200. Torque shows the same beginning then a fairly flat 260-280 lbft plateau all the way from 4000rpm to 6000rpm. AFR shows the same 'step' at 3000 where it richens to almost 11:1, then settles back to 13:1 from 3500 rpm onwards, almost straight as a ruler across the plot. This was the bit that was mentioned about it running a little lean according to the wide band on full load. Boost hits 21 psi at 3900rpm and stays virtually flat from there onwards.

Keep the comments coming!

StickyMicky

i ran mine on the rollers last wed

td05fe hit 1.4bar on the dyno (1.45 on the road)

i think i forgot to tighten up the actuator and it dropped boost after 5800, here is the wobbly graph



it was doing fine until the turbo went on holiday LOL
mate put his on the same rollers today and lost quite a bit more in trans loss

its a mate who actually owns this rolling road so i doubt hes "fudged the figures"

StickyMicky

should have added, i`m hoping to tweak the actuator sometime on monday and go back over for another 3 power runs to see if it makes a difference.

the big juicey splodge of torque makes me happy anyway

iirc mine is a 276bhp model wrx but i think my torqoe should be around 240lbft as stock

from the plots i had done when it was nearly stock, im getting peak power and torque about 1krpm sooner at the moment!

Baker

I know what you mean about it being a psychological barrier, when I first bought my Impreza it made 283 at the flywheel. at the local rolling road station in Plymouth. The car was very rapid but in my mind I always wanted 300+

Now making a very healthy 324bhp at the flywheel after a little tweak and remap, still going very strong with big plans in the near future! you would still be proud of the car James

Andy

silent running

I wonder whether I could get an idea of the underlying power that the engine is capable of by looking at the 2000-2000rpm power/torque curve and comparing with others? In this area with wide open throttle but before the turbo comes on boost, surely I should be getting an idea of its 'normally aspirated' capabilities? A low compression 2.0 16v lump...what should it make without the turbo? In fact what does the Sport make as an NA 2.0? Obviously the turbo will make less because of the lower CR, but it should give a guide, surely?

timchump

my 1999 uk turbo made 250bhp at the wheels which equated to 333bhp at the fly, with a vf34.

I have no idea how they calculate transmission loss but mine was 25%, your does look like it has been miscalculated imho

ZEN Performance

13:1 is too lean, it should be running between 11 and 12:1 (i wont be more specific than that) on boost. I would be looking at checking the fuel pressure, if the IDC is up at normal levels, then it's definitely a mechanical things. Otherwise check if the MAF voltage is reaching expected levels, it may expose a leak of some sort before the turbo.

silent running

Well you've presumably got the logs from the last mapping session Paul, I'll get it warmed up and take it for a full load run and get some peak numbers for boost, MAF voltage and injector duty. The latter two will be fairly low if I remember from the last time, if everything is OK. Also I'll have a look at the inlet pipe and fuel pressure. I'm right now wondering if I've got a slight leak at the joint at the front of the turbo, that's the most likely spot. I assume a leak there will be pulling in unmetered air, therefore outright boost pressure and spool up will be unaffected, but it will fool the ECU into supplying less fuel to match boost than it should do.

Let's say I find a leak in the inlet or an out of whack fuel regulator...will the lean mix have been the likely cause of the low power reading? Oh and while you're on here Paul; any news on the cold start issue that I mentioned before? CHeers

Mocom Racing

iTrader: (2)

Do you know the wideband was correctly calibrated or fitted to the car during the run; 21psi and 13:1 wouldn't mix well?

silent running

No, no idea. All I can do is take their word for it. The engine's pretty well heat managed though so perhaps that plays a role in keeping det down even if running lean on full load - the whole FMIC tract is heat taped (fibreglass / aluminium), header tank on insulating stand-offs, inlet manifold on insulating spacers, whole exhaust system from headers to just past the cat is heat wrapped.

I did two full load runs today, similar to what was done on the RR, one in the morning and one in the afternoon. Results off the FC Commander were so very nearly identical on both runs so I'll only just take the median. Note that it's a Z32 MAF, 440 injectors, SARD regulator @3.5bar (which seems to be still where it should be)

Idle figures were:
Vacuum -492 / Airflow 1070 / Injector duty 1.2 / RPM 850

Full load peaks were:
Boost 1.46 / Airflow 4110 / Injector duty 72.0 / RPM 6450

Knock very rarely goes into double figures. Charge temperatures are well under control. Any more ideas? I've not done a proper visual inspection of the inlet area - lack of daylight hours that I can spend looking over it!

ZEN Performance

I will check the log and compare the airlflow. I would guess the wideband could be out, but if other people had normal figures it suggests a problem elsewhere.

silent running

Well I was the second one on and couldn't hang around so didn't see what others got. The fella before me had a chipped Saab which made 230 I think.

Tidgy

mm, on a vf34, front mount, decat, induction kit, walbrough fuel pump and autronics ecu i got 341.somthing at 1.4 bar (iirc) so does seem down.

how much differance would the fueling make? (question to the experts lol)

would it be in the best interest to get it on another dyno to make sure?

silent running

I thought of that but dynos are scarce round my way...

jasonius

iTrader: (1)

IMHO, you have a decent PAW figure (244hp) but they've used a tranny loss figure of ~16% hence the 291hp at fly..!?

If you add the average loss figure, 244 PAW equates to more like 315 or:

20% = 305hp
22% = 313hp
24% = 320hp

Or am I missing something obvious..?

PS awaits those who claim losses around 15% and anything more is complete BS to inflate engine power..

TexRex22

those numbers seem a bit low to me. not to mention peak torque comes interestingly late. i have seen stock. i guess as long as it feels fast on the butt dyno

silent running

Think it's time to post up the plots. I'll try and work it out later today

andythejock01wrx

Jase, I think the Dastek system is a bit different and this explains the apparently low tranny loss. Andy F posted a few months ago confirming why this was the case (but i can't remember what he said ! ).