looking for a bit of information please. had a rolling road day on saturday with a jap car club. my figures came back at 376 bhp and 333lb /ft. now i had a road map last august showing 369bhp and 415 lb/ft (2.5 sti remapped) so obviously i was a bit worried by the low torque. but on checking it looks like the 4wd cars had lower torque than i thought they would have i.e a r33 gtr running 424bhp with 303lb/ft? so was wondering when they get a torque reading does the car have to be left in gear or in neutral on the rundown? sorry for long post but just wanted to know. cheers mike

 

A Subaru 2.5 engine will generally run more torque than bhp. My 2.5 car made 473 bhp and 480lbft of torque but my 2 litre car made 440bhp and 380lbft of torque.
As long as it drives fine on the road would not worry about what a RR says as there is so many variables that can affect the power reading.

banny

 

think they are left in neutral

 

to be honest im not all that worried. i love the way the car drives but was just wondering as it seemed only the 4wd cars seemed to be low and the 2wd about right.

 

Could be an operator error in that case!

 

Was there a boost curve graph from the most recent run?
What type of rolling road was it?
Presumably your first output was from Ecutek road dyno, produced by Bob Rawle after the remap?
Did he also give any wheel power/torque figures and what mods have you had done?

 

I think there are wheel figures on the spreadsheet that Bob sends with the graph.

If not, IIRC he assumes 22% losses, so presumably peak power and torque at the wheels will simply be 22% less than the figures quoted on the graph, which is flywheel power?

Ns04

 

That's why I'd like to find out if the 369/415 figures are from the Ecutek dyno output, or from a sympathetic rolling road run after the remap.

 

the 396/415 figure was the original road set up that bob printed off for me. the 376/333 figure was from the rolling road with 296 at the wheels. it just seemed to me that all the 4wd cars had low torque figures. one of the guys had a classic with a 2.5 bottom end that put out 392 bhp but only 310lb/ft of torque. i just thought it wold be higher

 

very random and not related but what does 'IIRC' mean. i see it everywhere but don't know what it means lol

 

Post the graph...if the torque and BHP lines don't cross at 5252rpm (when plotted on the same scale). Something isn't right.

Seeing bhp is calculated from torque. Mathematically, To achive a 100lb/ft difference with the same BHP would require a very different power delivery of the engine or a conversion/compensation calculation. I'd go for the latter.

The person doing 392bhp and 310lb/ft sounds very odd, which backs that up.


(IIRC - If I recall correctly)

 

well ive checked bobs graph they cross at 5200rpm the new graph from rolling road ( cant post pic yet) crosses at 5750 rpm. so thats not correct?

 

Its possible torque and BHP are not printing on the same scales (I hate it when they do that).

 

I'd go with operator error not setting the ramp rates right on the dreamo.

 

it says ramp rate 2 which seems to be the norm?

 

Post up the graphs mate - sounds like boost was well down on what it should have been to cause that drop in torque

 

will try an post graph, but wouldnt bhp be down with less boost? sorry for sounding stupid

 

early boost = torque

It may have still got the same/similar boost at the top end and hence the figures for bhp were similar

Boost graph will show lots of info (as would a fueling one)

 

Do you know what Bob set the target and tailing boosts to, or have you ever noted what boost you get on a gauge when driving?
I'm also very curious to know what other mods you have doen to the car?

Nick

 

trying to get hold of bob to find out what boost its set at to be honest, and i dont have a gauge. the car has had exhaust,fuel pump, plugs and sti panel filter and of course remap

 

Has anyone suggested that the OP may have unintentionally mixed Ft.Lbs and NM? Remember as well, that brake horse power and torque (however expressed) are two sides of the same coin, as oppsed to two completely seperate things.

I cribbed this from a page that explained it clearly:

1. POWER is dependent on TORQUE and RPM.
2. TORQUE and RPM are the MEASURED quantities of engine output.
3. POWER is CALCULATED from torque and RPM, by the following equation:

HP = Torque x RPM ÷ 5252

I wonder if this has helped.....

Simon

 

Well spotted simon - especially seeing 415Nm = 305lb/ft. So that leaves a more plausible 28 lb/ft to be accounted for

(1 lb/ft= 1.35581795Nm )

 

I had more than 305 lb/ft on my 2.5 STI without a remap.

he is not getting confused - there is either an issue with the rollers or an issue with the car

 

On the other hand, 415 lbft (340 @ wheel on an Ecutek road dyno run) on just a remap is exceptional - hence my questions about spec and boost levels.

 

Mine was doing 350 lb/ft at the wheels on std block, turbo and remap - sounds about right to me.

 

Can you PM me a dyno run file of that? I'm a bit curious where its all gone wrong for me.

Back to the OP, poor loading of the dyno or perhaps an up-pipe leak, but you'd hear that.

nick

 

I wish I could Nick but all my old dyno files were on the laptop that was stolen

 

OMG - I thought it was "just" the recent maps you lost.

 

this is the road map graph
[IMG][/IMG]

 

well just spoke to bob and he reckons the rolling road graph is right. he says boost comes on later on a rolling road so will not get same figure for road map and rolling road for torque and its at the wheels..............i think