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Discussion Starter #1
I might be throwing myself into a fair bit of controversy with this topic, but I feel that I owe it to the members on this board that I raise it nonetheless. I shall accept any criticism afterwards.

Now to my point:

I had a close look at some of the graphs produced by the equipment at PE. The main thing that I noticed is that the expected rapid increase in torque at around the 2000RPM mark, and its subsequent more or less constant maintenance for at least another couple of thousand revs, is missing.
Looking at the performance graphs from Mark E from both Maptune and PE, you can quite easily see what I mean. Anyone familiar with the SAAB performance curves should know what I mean.

OK, I accept that a modified ECU would not adhere to the original OEM curves, but a radical departure from the original curves is something I question.
I am particularly worried about the low-end torque from the PE results. I find it hard to believe that those readings can be true. Every SAAB owner with a turbo knows that
means a kick up the b*ckside from very early on in the rev range. Those PE graphs paint a completely different picture.

As you may have gathered, I am extremely disturbed by all this. I can be extremely sceptical at times, and none more so as on this occasion. Especially after reading in between the lines of a view visitors to PE, who were less than impressed with the produced results.

"Blasphemy" some might say, but I'll go ahead and ask it anyhow. Are those PE measuring methods trustworthy?
 

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Stanleyb,

What do you make of these?

This is a standard CS Aero dyno run, NO mods what so ever. Dyno has the same 2 dials that can be seem in some of the pics from yesterday.

Power top, torque bottom




Andrew
 

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PE use a MAHA RR which is very commonly used and is well respected in terms of RRs. Whether it reflects accurately what you feel on the road, however, I don't know.

If you go back to my post (under Drabux) and take a look at Rich Ward's, Tandino's and my run you can see in all three a sharp rise in torque from around 2500rpm. Some of the others that do not display this characteristic e.g. Alex's and Mark's. This may be due to the fact that they both run bigger turbos and, hence, torque comes in later. I think Mark mentioned that his stage 5 ECU brings in power and torque gradually rather than as a wollop. The plot seems to reflect this.

Alanb
 

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Discussion Starter #4
Those graphs from Scaero owner are just the type of graphs that I would have expected. The torque graph especially is more in line with the general SAAB performance graphs. The rapid build up of torque (around 310lbs/ft! Eyes well back in their sockets at that level in the lower gears no doubt!!)is instantly recognisable as a SAAB "feature", and unique amongst turbo cars.

Where and when were those taken Andrew?
 

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Those were take at Autopoint in Thetford 5 years ago, when the car was due a major service.

Mileage was 97,000m if memory serves and:-
the RR set to 3000lb load,
temp 15C,
barometric 1002mb,
max torque at 2578 in 4th at 57.5mph,
Max power at 4753 in 4th at 106.0mph.
Power losses 45.7bhp. (giving 202.8bhp @ wheels)
Max engine speed in test 5649 in 4th at 126mph
(edit: just looked the figures up!)

The car is now at 133,000 and probably due another RR.

I took it in lasty time as I though is weas slugish low down, which the graphs proved, but when I saw the extra it was giving higher (+10% power, +20% torque) I left it.

I was going to have it chipped back then but decided not to. I'm now thinking of Elk stage 3 i9ng it to see if I can release a few more bhp/ftlb as I now have the 2.3 Carly to play with too.

Andrew
 

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Stanley,
To a large extent (but not totally) the difference is an optical illusion, due to the different x and y axis scales between the two plots.

Referring back once again to the PE plots you will see that many cars e.g. Richard Ward's car and my car reach very near maximum torque by between 2700 and 3300rpm. However, the rise doesn't look steep because the x axis is stretched somewhat.

Alanb
 

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I think it has to be pointed out that the modified cars will necessarily produce their peak torque at a higher point than a standard car due to the modification of the ECU allowing more boost. This however cannot be produced at low rpm as the mechanics of the turbo havn't been altered, all the ECU does is allow more boost where the standard program would hold it back.
Looking at it another way, the nice flat torque curves of many turbo cars today are just the result of the ECU cutting the peak off of what would happen if no (electronic) restiction was placed upon the engine.

By the way, my car, measured with an AP-22 accelerometer gives a strong surge of torque up to 2300 rpm then slowly gathering itself to a peak at 3500 rpm then rolling off slowly to the red line.

Nick.
 

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If it'll make you guys feel any better, my Hirsch ECU tuned 9-3 peaks it's torque at 3170 rpm according to their dyno. It is also a Maha dyno. I think the torque cruves, like stated earlier are changed due to the higher boost pressures. Mine actually has the appearance of a stock curve however it just peaks later. Also, the spike in it is not very noticeable since Hirsch spent much time trying to smooth out the boost spike. Hope this helps.
 

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Originally posted by StanleyB:
[qb]The rapid build up of torque (around 310lbs/ft! Eyes well back in their sockets at that level in the lower gears no doubt!!)is instantly recognisable as a SAAB "feature", and unique amongst turbo cars.
[/qb][/b]
I am not sure what you are getting at here, StanleyB? I was lucky enough to be given a Hirsch 9-5 Troll E (250bhp) for four days to drive and a Hirsch 9-3 Stage One for three days. Neither of these Saabs exhibited the characteristics you describe.

Having also driven standard 9-3s and 9-5s and Speedparts 9-5 Stage Two and Speedparts 9-3 Stage Two I would describe the delivery of power quite differently. The power comes in progressively at an increasing rate. The best way I can think to describe it is like a rollercoaster in downhill freefall.

The eyes well back in their sockets in lower gears is not how I'd describe it - I associate that more with my 99 Turbo or the 1984 900 Turbo two door that the local dealer used to lend me. On both of these there was a small lag between planting your right boot and the thing taking off like a scalded cat


Modern Saabs are much more refined, smooth and progressive, are they not?
 

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Modern Saabs are much more refined, smooth and progressive, are they not?
 [/b]
I have to agree,You would not know the modern Saabs are a Turbo as such,when mine was a lpt it just felt like a normally asperated engine.And now it's fpt low down you can't feel the Turbo come in but at high revs it just seems to launch the car forwards
 

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I am particularly worried about the low-end torque from the PE results. I find it hard to believe that those readings can be true. Every SAAB owner with a turbo knows that  means a kick up the b*ckside from very early on in the rev range. Those PE graphs paint a completely different picture.[/b]
I agree with you there, I agree that my peak torque is at 2500ish as the plot shows. But it's about 60lbft short of what I would have expected and to be honest I believed from the
factor (when driving) that I was getting near 300lbft of torque at those revs.

Obviously I'm running everything standard, OK, so people suspect that my APC has been tweaked, I don't and I've been suitably assured. So I would expect that with the boost drop off torque would fall (the dyno result shows this) leading to a peak power output around 230-240bhp.

That said I'm not massively disappointed with my results, after all, I've not spent £K's on engine mods. Still, I would like to go somewhere else for another opinion.
 

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I tend to agree with Stanley. Saab claim 258lbft at 1800rpm for the 9000 Aero and if you floor it on a steep hill (so the turbo spools up before the engine speed rises significantly), then you will believe it.

The flat torque curve from low RPM is missing from many of the PE plots. I don't really believe any of these mods reduce torque at low RPM on a turbo car. They just allow the boost to rise farther, and the new, higher peak is further up the rev range.

I had wondered before whether the dynamic measurement technique was suitable for an engine that didn't respond instantly. See the "311hp" thread for my results on a static rolling road, compared to my results from PE. They are very different, even though peak horsepower was around the same.
 

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I don't know about the 9-5, but my 9000 2.0LPT doesn't feel like any normally-aspirated engine I've ever driven. Perhaps I've never driven a car with a 4.0 litre normally-aspirated engine that doesn't like to rev too high, because I suppose that's what the 2.0LPT feels like. Instant pull, practically from idle speed, running out of steam at around 4000rpm. Definitely Saab's trademark.

I thought /john's car felt similar, but obviously a lot more power and more willing to rev. You still get the low-down pull, though, that is missing on normally-aspirated cars.
 

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Here's something useful then...

An early plot of Bubbles from PE, overlaid on the one from Saturday. At the time, she would have been fitted with the Abbott ECU, exhaust, air filter and I'm pretty certain still the standard 2.3 turbo.



P1 & T1 are the earlier curves, which I think you'll agree look like what we would expect.

I reckon what this shows is that perhaps, as has been hinted at, bigger turbos take more time to deliver their maximum welly- after all my run took a little over 8 seconds from start to finish.

The question I might ask PE is whether or not it's possible to lengthen the time taken to do the run. Having checked the video footage, it's clear that the lower powered models were taking 2-3 seconds longer to complete the run than mine.

And for completeness, a graph showing boost too...

 

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Mark,

Your torque and boost match quite nicely.

What are you going to do now to keep that 2 bar level to 6000rpm???

Andrew
 

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A very non-technical point here:

One thing I noticed (and perhaps Tandino can check since he videoed the runs) is that on Saturday the two round dials on the RR gauge were reading much higher than last time for all runs. When I did my run I think that the needle on the left-hand dial only managed to sweep a third of the way round vs. 2/3rds or more for many of the runs on Saturday.
What do the dials show? Does this suggest that the RR was set up differently?

Alanb
 

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I would assume that the dials are power and torque or speed and power. (with a little 3 char led display underneath)

Andrew
 
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