Had my P1 dynoed at Tuning Japanese today. It has a full straight through exhaust and downpipe (no cats or resonators), and a Dawes Devices MBC set to 1.175 bar.

Seeing as the Prodrive claimed figure for the car are 280 bhp and 265 lb/ft torque, I was expecting 280 ish torque and over 300 bhp. To say I was dissapointed is an understatement..

Actual figures:

Power 291.5 bhp @ 7310 rpm
Torque 236lb-ft @ 5470 rpm

How can the torque figures be so far out? Is my car ill, or were Prodrive talking out of their *****? UK cars with PPP get far higher torque figures than this - maybe I should have got one of them instead!

Any ideas?

MS

 

I'd almost bet vital parts of my anatomy that your cars ecu thinks it's detting...or sparkling at least, the low torque figure is an indication of retarded ignition...still horsepower is a product of torque...weird - maybe you ought to test it at another RR (if possible).

Anyway, here's what I'd do.
Remove that MBC (they are crap anyway), and try it again, try to get the operator to use det cans to spot if it's in fact detting...if it is and torque is still is down, replace the downpipe, and get at it again.

What fuel are you running it on?



/J

 

...and seriously...if you're looking for more power, get it mapped.

/J

 

Martin

The positions of the fans at T-J are bias towards front mount intercoolers, so don't worry too much(IMHO).

Best bet is to take it to Power Engineering.
My P1 got 261Bhp & 219lbs torque @ T-J, but was blatantly quicker than a standard P1/STi 5.

Rgds, Alex



[Edited by DrEvil - 12/20/2001 12:08:51 PM]

 

Ok so my MY00 PPP turbo has 238lbs of torque, not alot in it is there! (and you have a little bit more bhp than me as ive only got 249 )

Tony

 

302 bhp and 282 lbs of torque for me Martin with a scorpion de cat and itg panel filter back in August.....more done since then !
Chris

 

Hi Guys,

thanx for the replies so far.

SecretAgentMan,

I ran the car today before fitting the MBC and the torque figure was the same, bhp was about 2 or 3 brake less. The torque curve between the two runs shows that the torque remains flat all the way to the redline, without dropping off at 6k rpm as it did before fitting it. I don't think the car is detting, Ike at Tuning Japanese said that the car was running plenty of fuel and I was running Optimax too.

I can't understand how the bhp figure can be so respectable and yet have such a low torque figure. I thought bhp and torque were interlinked - surely a rise in bhp should mean a similar rise in torque.

How can the torque figure be so low when the bhp is so much higher?

Totally confused, can anyone shed any light, do you think my car is detting!?

Thanks in advance..

MS.

 

Martin,

it baffles me aswell. My car on PowerStations rollers showed 228lbs and 275bhp and on PowerEngineerins rollers 238lbs and 295bhp.

????

 

Martin

Running you car in isolation is one problem. Did any other Scoobies run before or straight after you ?. You need to compare your torque against another cars torque. A std UK car might only have got 200lbft.

As other have said, try PE and see what you get there before worrying. So any P1's have been on there, and the road IMHO is pretty accurate.

I have always been of the opinion that the P1 produces approx 250 odd lbft when new, the same as an STI V. So a little down on claimed figures. I also found the the same with the UK300, and I bet the STI VII will be the same.

That said the only real way to get a figure is to bench dyno.

Jonathan

 

Martin

Relationship between torque and power is Power = TorquexRevs/5252(roughly!!)So you can have lowish torque at high revs and still see "Good" power figures.Your peak torque seems to be at quite high revs which could indicate lack of low down boost and/or advance.Your respectable power is achieved at high revs (7000+) in other words where the torque doesn't have to be high due to the calculation above.

The real point is don't get too hung up on power! Torque is what is giving you the acceleration as this is the turning force on the wheels.

Hope this is as clear as mud.

Steve

 

Nothing wrong with the "Dawes"MBC.For value for money on a Scoob,it wins hands down.

 

Martin,

I've got the same problem only worse!!

Had my STi4 (with decatted exhaust and downpipe) tested on the RR at John Noble's in Chesterfield a couple of weeks ago and although bhp was ok, torque was about 50 lb/ft down and I was told it was overfuelling badly.

275 bhp @ 7130 rpm
ONLY 208 lb/ft @ 6860 rpm

Very disappointed - but having my poorly car checked on the select monitor at TSL to try and find out what the problem is. It has been suggested that the Lambda sensor could be faulty.

Lizzy

 

I cant understand why someone would fit an mbc to a P1.

You have already spent the money on on of the most expensive standard subarus there is, yet you then put on the cheapest method of improving the performance, and even tell us it has gained you 3bhp max and not changed the torque.

I would ditch it and do it properly with an exhaust filter and then an ecu.

Your peak torque is low, but if it holds all the way to the redline then the higher it gets the greater your power will be. If you peak power is at very high rpm then it will be able to salvage a good figure from a low torque figure.

Take chins advice, and run it at PE.

 

One fina point to consider perhaps, is the bore of your exhaust? Large bores favour top end power rather than midrange torque - if you have an exhaust with a large bore, this may be a contributing factor.

Mike

 

I have a full exhaust, air filter, chargecooler and Link ECU - and a Dawes...

Martin has already said that it doesn't make much difference to the figures - what about the power delivery ?

I think the Dawes is a bit of a red herring but I would urge people not to knock it unless they have tried it...

Thanks

Gavin

 

Just a quick thought. They didn't do the run in 2nd did they? If they did, then the 'emissions mode' could have cut in, and held around 9 psi up until about 5500rpm, when the full boost is released...

My MY00 (both before and after PPP) have done this, and I'm sure the P1 is no exception...

Just a thought
Richard

[Edited because no car can hold 9 bar meant 9 psi!]

[Edited by Bitten Hero - 12/20/2001 12:13:36 PM]

 

Tuning japanese are pretty careful on their power runs from what I saw. They were using detcans on all the runs on the scooby day recently. And they always run the car in 4th as do all the RR's I've been to.
As pointed out the peak torque was pretty high up the rev range so thats why it is a lower number compared to the BHP figure. Power delivery seems to have changed alot with the Dawes thingy.
Chuck

 

Forgive me for being daft, but aren't the measured figures "at the wheels" and the manufacturer quoted figures "at the flywheel"? Did you do the conversion?

 

LizzyWhizz,

ONLY 208 lb/ft @ 6860 rpm

Max torque should be somewhere around the 3500rpm area. Yours sounds v. strange indeed

 

Has anyone considered that the rollers might be out?

 

Lizzy

The thing is sweetheart, is that you have a wagon (Runs for cover )

Mikey

Are you coming to TSL this Saturday?

 

Thanks again for the continued replies, interesting comments indeed..

My car has a straight through centre section, Magnex twin dump downpipe and Powerflow backbox. The entire system is 2.5" bore all the way through with no resonators. I deliberately went for the 2.5" over a 3" because I didn't want to compromise my peak torque figures.

Adam,

the reason I went for the MBC was to enable me to hold the boost on my car to the red line. As standard, the boost drops off at around 6k revs, so this is now much improved with the MBC. I was not expecting any real increase in power, as the boost as standard was at 1.1 bar, and i didn't want to go much higher than this anyway. The Dawes MBC offers a reliable way to control boost, i can't see the problem with it, - what's your objection?

Back to my main thread, I would really like to get to the bottom of my low torque figures. If it was due to the rolling road, then I would have expected bhp figures to be low too, but they were close enough to what I expected with the exhaust mod.

Could the car be over-fuelling? If so, can this be altered without buying any other chips or devices such as an AFC?

What power figures have others got on their STI's or P!'s with similar mods?
Is this low torque figure normal, if so, then maybe I'm not so worried.

Any other ideas, comments or suggestions??

Any Scoob specialists care to comment, Pete C, Mike Tuckwood, Mike Wood even?

Cheers,

MS

 

>>the reason I went for the MBC was to enable me to hold the boost on my car to the red line

Not meaning to be funny, but if that is what the MBC does ... GET IT OFF AS SOON AS POSSIBLE. (sorry for the shouting)

I'm not an expert, etc... but you can trust me on this one.

Your turbo nor your engine are designed to have 1.1 bar at say 7000 RPM or higher.

There is a reason (a damned good one) that the ECU changes the duty cycle on your boost solenoid over say 5.5 to 6 k RPM...

It should however not affect your midrange torque, unless your car is detting as hell, so the ECU retarded ignition as far as it could.

I don't have to work for Prodrive to know this ****...

Theo

 

martin

if you fancy a comparison i quite fancy a run on a dyno with my P1
so we could put our cars on together!
my only mods are magnex centre and milltek back box.
drop us a mail

pete

 

I'm no expert on Scoobs, but I've been playing at getting the best out of Turbo charged Saabs for a while now. Winding your boost pressure up and doing little else gives you a nice dose of torque, though without upping your fuelling (engine management will do what it can) you wont get any more power. You have power, but not much torque, so I would say your not running enough boost for the fuel that is being thrown in. I would lean it out a bit or raise the boost.

 

Just want to back up Theo's (EvilBevel's) warning - the reason the boost is backed off above about 5500rpm is that the injectors etc can't reliably fuel at a high enough rate, and so the engine runs lean. This results in detting and BAD news after a while... Sounds like the car would benefit from a proper dyno run with diagnostics, like det cans (for spotting pre-detonation), exhaust temperature monitoring (for spotting running lean), etc...

Like someone said earlier, it seems a bit mad spending so much on such a nice car, and then spending just £25 on something that could (quite literally) blow the engine up. Get it sorted by a specialist - if you want to hold the boost up that high, sort out the injectors and/or fuel pump etc and get someone (e.g. Bob Rawle) to map it properly using a Link system.

Just my twopenneth but would hate to see a thread "Dead engine in P1!!" in a few months' time [img]images/smilies/mad.gif[/img]

Richard

 

I am glad someone else can see my point of view.

 

Bitten, ta for the backup , but just one small thing: a lot of people will now be thinking "but it is not running lean, I checked that" and decide to keep the stuff anyway.

Problem is, even if the mixture would still be OK (and you can discuss what's OK or not, and I'm being academic for a moment), the turbo will be out of it's designed compressor map and will seriously heat up the intake air (120° plus), causing det anyway, rich or not. Now, the two combined is even worse of course

 

I personally wouldn't put a boost controller on a P1 either.

UK cars are a bit different as they tend to overfuel ridiculously, and even holding flow limit of the turbo to high revs (about 13-14PSI) it is still perfectly rich enough but who knows what the intake temps are (I wouldn't run on a track without knowing), backed up by the good long term results some have had. However, I don't tend to rev it beyond 6000rpm as there is at least as much shove from changing up.

However, one poster above is suggesting you need it leaned out, others are suggesting you injectors are not keeping up.

Would think you need diagnostics as pointed out above.

[Edited by john banks - 12/20/2001 2:23:06 PM]

 

There are a number of parts which cost less than £25 which could "lunch" an engine quite comfortably - the Dawes is not the only one by any means .

Personally, I wouldn't rate the chances of survival of any turbocharged engine over the long term with a 120 degrees C (???) intake temperature.

Where does this figure come from ? Even with my old "slanted" intercooler which is famously inefficient (albeit with a TD05H), 70 degrees C was the absolute maximum I ever saw...

Each car is different so intake temperatures, fuelling and knock limits can vary even between identical models so caution is mandatory.

Maybe John can measure his intake temps over a couple of weeks to see what REALLY happens.

The threads regarding the Dawes thus far have been open and objective with no "rose-tinted glasses" evident.

Please bear in mind that expressing an opinion is one thing, scaremongering is quite another...

This thread seems to have turned from a discussion on RR figures to a Dawes MBC "knocking" session.

For £25, it keeps the wastegate shut (as does any number of electronic boost controllers) - which is exactly what is stated on the web site: Here

As previously stated, the solution is simple - set it up properly whilst checking the fuelling with a wide-band air/fuel monitor and det cans on a rolling road.

Thanks

Gavin