rr day

[col1n]

well finally got the vr4 on the rollers at hypertech in bonnybridge yesterday
and here are the results, not quite what i expected


as you can probably see here something aint right



it made 205 bhp and same kind of torque with practically no boost at all, so anybody want to volunteer to help please
and its running very very rich

[elnevio]

The AFR doesn't look unusual for a stocker PFL auto. The ECU just dumps more fuel in, so an AFR dipping into the 9s is not unheard of.

Boost looks not far off the right level for a PFL auto, peaking at about 0.55 bar. But it does look a tad low in the earlier part of the rev range (I wouldn't expect it to increase before tailing off).

Did the operator actually give you the at the wheels figure - and used the right correction factor for the transmission? This should be something like 'Centre Viscous Coupling - Shoot44 mode' (according to Ben at Eurospec anyway - and possibly mis-regurgitated by me!). And did he apply a conversion factor for the auto transmission losses?

What fuel are you running it on?

[Kieran]

The 'Flywheel' BHP is a calculation and isn't terribly reliable. In fact I'm reluctant to draw any conclusions about the state of your car for that reason.

Do you have the 'Wheel' figures for bhp and torque? They'd give us a better yardstick.

As for boost & AFR. The AFR is what i'd expect to see on a VR4 with no additional fuel control. Yes - They do run stupid rich on the standard maps.

As for your boost. That looks a tad low, but not massively. The boost creep up at the end suggests you may be running wastegate pressure (If I'm reading the graph right, IE it's about 0.44 bar then climbs to just about 0.6 briefly?). This is not unheard of - the connectors on the stock boost control solenoid do go brittle and the vacuum lines can also leak.

Hope that helps!

[Wodjno]

Thats pretty reasonable if that is a wheel figure.. And your AFR's are about right for a car that hasn't had the fuelling sorted(A tad leaner than most) Your Boost looks a little low though.. Maybe a leak somewhere.. ?

[Eurospec]

Looks like it was run in shoot 44 which is correct, and it must have been in the right transmission mode- if it isnt the dyno shuts down the run to prevent transmission damage.

The afr is rich, but its actually pretty typical of what you see on stock cars.

Obviously its an auto- you see the huge torque peak at the start of the run where the tc loads up.

The run has been started very low in the rpm though, but depsite that it is making boost there 0.4 bar at 1200 rpm isnt bad eh?!

The figure given is the est flywheel power, uncorrected for auto trans, so the actual power is higher- eg the 7%.

The power curve is the right shape, the afr is where you might expect, but the boost is low. I doubt at 0.6 bar it would make a lot more power, but first place to start is the hoses etc. I would then check the timing.

Cheers,

Ben.

[fluffnik]

well finally got the vr4 on the rollers at hypertech in bonnybridge yesterday

Ludolph is going on the self same rollers on Saturday - at a BMWCC RR day!

I'll post my results when I have 'em.

[bradc]

What fuel have you been running it on? It could be running on the rich map which will affect your AFR's and power

[col1n]

The AFR doesn't look unusual for a stocker PFL auto. The ECU just dumps more fuel in, so an AFR dipping into the 9s is not unheard of.

Boost looks not far off the right level for a PFL auto, peaking at about 0.55 bar. But it does look a tad low in the earlier part of the rev range (I wouldn't expect it to increase before tailing off).

Did the operator actually give you the at the wheels figure - and used the right correction factor for the transmission? This should be something like 'Centre Viscous Coupling - Shoot44 mode' (according to Ben at Eurospec anyway - and possibly mis-regurgitated by me!). And did he apply a conversion factor for the auto transmission losses?

What fuel are you running it on?

the car was 205 atw, and as far as i know it was done as shoot44, and dont think he used a conversion factor
the car is always run on v-power

alistair- its a good day out, the guy that runs it is called duncan and hes a top bloke (older bloke). was given good advice from him aswell but he didnt know enough about the cars

[fluffnik]

Got the result: 218.3bhp @ 5800

I'll get the plot scanned later but the curve is broadly similar to col1n's in shape.

I don't seem to have an AFR and boost plot.

...the considerable richness was discussed at the time though.

A good day out, even though the rollers would not play nice with ///M5s...

[fluffnik]

Here's the plot - bottom end of the torque curve makes no sense to me...

[bradc]

Torque Converter flare