bottom end power

[HARMFUL 81]

What are the options to increasing the bottom end power/torque for a standard I6 wagon. It seems to be struggling a bit under load lately (family plus trailer up hills) Thinking maybe a checklist first then possible mods.

[HARMFUL 81]

I should add, when it hits 2.5-3k it hits some sort of power band and gets up and boogies - is there something obvious restricting bottom end performance?

[The Monty]

2800rpm stall converter. Youll need a tranny cooler as well. Well worth it.

[Mr Hardware]

uh, i wouldnt recommend a 2800rpm stall converter on a family wagon.
make sure your car is fully serviced - oil/oil filter/air filter/fuel filter/plugs/leads/perhaps clean injectors/trans service/diff service etc
should be the quickest and cheapest way to return to some better power.

[HARMFUL 81]

out of the list provided the only things that havent been done recently are the air filter, fuel filter leads and diff service. I was thinking of doing the fuel and air filters soon.

[glennb]

if its an auto they are pretty gutless down low. Best thing would chuck a 3.45 diff in the rear or a 3.7 . I have an au xr6 and still find it could have better low down power. Im thinking a 3.7 but for a family wagon and trouble free with still excellent fuel economy go the 3.45 it should be enough for your needs.

[HARMFUL 81]

im not too sure on the ratio it has in there. It has an LSD, one that im not too ready to part withfor the sake of a bit more power.i was hoping there would be some relatively easy mod to give more bottom end.

[The Monty]

Why not a stall for a family wagon? You want a bit of go, its either that or diff gears.

[Whoosha]

What other Mods does it have ?
If its stock why not go with the standard Zorst.Cai,& Tune.

[private9]

They're very sluggish off the mark, so sounds pretty normal there.

As has been mentioned an exhaust will liven it up a little.

Either shorter diff gears, or a stally will wake it up off the line.

I wouldn't worry about driveability with a stally under 3k. As long as it retains lock up it'll still driver nicely.

Might help with suggestions from people if you post up a budget and what sort of mods you'd put up with!

[Sox]

If you're wanting more power for towing up hills when loaded etc, then I would look at extractors and a 2.5" sports exhaust.

The next step would be to change the rear end gearing, those autos are notorious for being sluggish down low and it's mainly to do with the very tall 1st gear and large gap between 1st and 2nd.

Swapping diff gears for 3.45 or even 3.7 would help response down low and shrink the gap between 1st and 2nd.
This will be at the expense of relaxed cruising ability on the highway though.

The usual cheap stuff would also be a good idea, like larger intake snorkel blah blah blah. This is probably not as critical though as you're not chasing upper RPM power, so ultimate flow is essential.
What you want is to optimise is low RPM ability and gearing IMO.

Lastly you could look at changing the cam to perhaps an XR6 cam, or at least advancing yours with a vernier gear.

I would not recommend a high stall converter.

EDIT - Also, make sure the BBM manifold is operating correct, in that the valve is actually switching over to the long runners below 3800rpm.
From memory the default is stay in short runners if there is a vacuum fault. This will kill power below 3800rpm.

[EBIIBurner]

i read in my manual that the ba and bf falcons have something called a
Broadband Vacuem motor, it says that it restricts the throttle from opening to 100% until the car reaches 3800rpm, does anyone know if you can over ride that, i suppose that might be one of the things a flash tuner does. It would also explain why with my EB the wheels would spin easy on a slight incline but with the ba no chance

[mik]

Originally Posted by EBIIBurner

i read in my manual that the ba and bf falcons have something called a
Broadband Vacuem motor, it says that it restricts the throttle from opening to 100% until the car reaches 3800rpm, does anyone know if you can over ride that, i suppose that might be one of the things a flash tuner does. It would also explain why with my EB the wheels would spin easy on a slight incline but with the ba no chance

i would imagine compared to your EB the B series would have a fair weight penalty.

[EBIIBurner]

Originally Posted by mik

i would imagine compared to your EB the B series would have a fair weight penalty.

that would be a contrbuting factor but it will still be good if you could by pass that Broadband Actuator thing that would give a little more bottom end

[JC]

Originally Posted by HARMFUL 81

I should add, when it hits 2.5-3k it hits some sort of power band and gets up and boogies - is there something obvious restricting bottom end performance?

The symptoms described fit a blocked cat almost perfectly - only thing missing is heat. Easy way to check for that is once the car is up to running temperature, stop the car and let it idle, and check the heat of the exhaust gasses at the tailpipe - they should be warm only; if they're very hot, then your cat is more than likely very stuffed.

This is exactly what happened to my old EL - doughey up to 2500rpm, so I replaced the cat based on mechanics advice (thinking there's no way it would work), and it magically freed up all that hidden power!

[Sox]

Originally Posted by EBIIBurner

i read in my manual that the ba and bf falcons have something called a
Broadband Vacuem motor, it says that it restricts the throttle from opening to 100% until the car reaches 3800rpm, does anyone know if you can over ride that, i suppose that might be one of the things a flash tuner does. It would also explain why with my EB the wheels would spin easy on a slight incline but with the ba no chance

It doesn't work like that.

The BBM (broadband manifold) is a fancy dual runner inlet manifold.
One set of runners is a certain (long) length to optimise low and midrange power, and then there is a second set of runners half (short) the length of the 1st set, to optimise top end power. There is a set of butterflies within the manifold which controls the seperate runners. This butterfly is controlled by a solenoid operated vacuum device. The solenoid receives a signal from the ECU to operate at 3800rpm.

So no, disabling the long runners below 3800rpm won't help bottom end power, in fact it will lose around 40nm.

The BBM is a very clever design, basically it's having your cake and eating it.
It's hard to improve it, until you're up over 180rwkw.

[onfire]

Get a decent complete service done first, if you havnt had one recently. I had one yesterday, and it feels alot healthier right across the board. If its not a significant enough improvement, atleast you'll know the car is running at its best when you decide on what you're doing with it.

[EBIIBurner]

Originally Posted by Sox

It doesn't work like that.

The BBM (broadband manifold) is a fancy dual runner inlet manifold.
One set of runners is a certain (long) length to optimise low and midrange power, and then there is a second set of runners half (short) the length of the 1st set, to optimise top end power. There is a set of butterflies within the manifold which controls the seperate runners. This butterfly is controlled by a solenoid operated vacuum device. The solenoid receives a signal from the ECU to operate at 3800rpm.

So no, disabling the long runners below 3800rpm won't help bottom end power, in fact it will lose around 40nm.

The BBM is a very clever design, basically it's having your cake and eating it.
It's hard to improve it, until you're up over 180rwkw.

thats definetly put it into perspective now i get it cheers (The manual should go into more detail about some stuff)