jlashley2001ss

iTrader: (5)

What can i do to "pick up" the poor accel. from 30-50mph range on an A4. As you can see below i already have an SY3500 tc and ive had my shift pts. bumped up all the way through and Torque Management deleted. What else can I do to get better in this range? TIA guys.

MTN_Z

iTrader: (7)

I guess 3.73s would be the next step if you really want it to pull hard from that range.

BIG BAD BLACKSS

iTrader: (4)

you can get a 6 speed!

NxLS1496

iTrader: (1)

3.73's would help alot, although you might lose some gas mileage, 3.42's would be ok too.

GXPPOWER

i cant belive even with a 3200 stall you still have no pull at the 30-50 range.... doesnt seem right.

jlashley2001ss

iTrader: (5)

well dont get me wrong it def. helped but we all know that even with the stall converter this range needs help.

staringback05

iTrader: (8)

honestly i know how you feel, you get on the highway and your at like 45-50 and it just drops and you get the horrible power band where its like 1000rpms and barely moving until u get around 65....just feels weird

99camarosupersport

iTrader: (6)

4.10's....

jlashley2001ss

iTrader: (5)

i dont think i wanna go with 4.10's....gas mileage would be horrible

staringback05

iTrader: (8)

also seems with 4.10s hed loose considerable top end. when its like almost 3krpms at 70

Ell Ess Won

I got the 3.73, I think it def. picks these cars up. punch from 50mph feels awesome!

On the highway cruising at 60mph I'm @ 3k RPM's...

'Trust'

iTrader: (24)

Its an auto, it doesnt shine its best from a roll, but I think you can safely downshift to first (via tuning) at 41MPH, its probably not the most efficiant since you'd probably see a better gain dropping down to 1st at a lower MPH but its ok to do it. Other than that, I'd honestly just avoid rolls from those speeds.

staringback05

iTrader: (8)

lol thats why you punch it around 20-30mph i know at least mines got a great pull aroud that speed, and i couldnt imagine running 3krpms at 60-70 eww i know ive got stockers, but it feels good to see 2krpms at 85....its like wow i have so much room

Ell Ess Won

I've never taken her over 100mph and dont plan to. :p

300bhp/ton

This is all about gearing and IMO 3.23 is one of the worst setups for A4 Fbody's.

Sure from a dig the 3.23's are ok if you go to WOT straight off but from a roll they leave a great big dead spot.

30mph I would have thought was ok, but maybe 33-35mph area would be the start of the dead spot.

30mph in 1st is 3900rpm and I would have thought it would kick down to that from a roll. 35mph however is 4500rpm which it probably wouldn't shift down to as standard which means 2nd gear is all you are going to get at that speed, but that equates to 2400rpm which is why the accelaration is pretty flat.

the same goes for 50mph, that would be the red line in 1st so when you floor it the gearbox will only kick down to 2nd gear, but it would still only be at 3400rpm hence it still won't feel as fast as it should.

If you want to roll race with 3.23's then 25-30mph is probably a pretty good low speed start and 60-65mph for a higher speed roll, anywhere in between will be a flat spot for the gearing.

How can you get around it?

Well there's several answers. If yuo have a good bolt on cammed car then you can increase you shift points, kickdown points and red line to give a greater terminal speed in gear and more flexability.

Stock the A4's shift at 5850rpm hence it won't kick down to anything above 4400rpm because the duration in gear would be too short, but increasing the shift point to say 6300rpm would mean you could allow it to kick down at much higher speeds.

Evidently you need a cam appropriate for this setup though and it does make for quite an aggressive style of driving and shifting.

Changing your final drive ratio is your other option.

Strangly enough 2.73 geared cars don't suffer this same flat spot. This is due to the fact that they can achieve higher terminal speeds in gear. They will kick down to 1st from speeds upto 39-40mph which will actually bring you in right at PEAK torque of 4400rpm. This makes then good for low speed roll races. 50mph is a dead spot because it won't kick down to 1st only 2nd gear which is only 2900rpm. So you can see the flat spot still exists just at different speeds (typically speeds which are not as common for roll racing).

However due to the taller gearing of 2.73's the in gear accelaration will be less, hence from a dig a 3.23 car should be the faster. But from a 35-40mph roll with stock cars the 2.73 geared car would pull ahead and probably maintain the lead until 100mph at least.

So the next step is to lower the final drive ratio (numerically increase). Common gears are 3.42, 3.73 and 4.10

Now all of these will increase your crusing rpm which will affect mpg. But they will also lower your terminal speed in gear which can be an issue if you typically run to higher speeds.

Before you choose on gears however it's worth considering a few factors.

First off these 4l60e gearboxes are really only 3 speed with an Over Drive and not 4 speed boxes. This means that for WOT kick downs you really should have the box in D (3rd) and not OD (4th). This is less damaging and also the gearbox will react quicker.

This means your top speed will be limited to your red line in 3rd.

Assuming stock limiter this would mean with:

2.73 = 158mph @ 5650rpm (which is actually the speed limiter not rpm limiter)

3.23 = 142mph @ 6000rpm

3.42 = 134mph @ 6000rpm

3.73 = 123mph @ 6000rpm

4.10 = 112mph @ 6000rpm

As you can see 4.10 gears severely limit your high speed ability and if you regulary top 140mph then only 2.73's & 3.23's will be able to achieve this.

Ways around this are to increase you rpm limter and shift points, but without a suitable cam setup you may not benefit from this.

Run larger tyres, but this will offset the point of running lower final drive gears (N.B. Remember numerically higher means lower gearing ).

So it's all about deciding what the car is used for. At the 1/4 mile 4.10's or 3.73's on the correct setup will work very well, but for me I often want to blast up to 120-140mph even often up to the 158mph limiter so such gears would be of no use to me.

If I go n/a cammed setup I'm getting 3.42's as with an increased rpm limit to 6500rpm I should still lbe able to top 140-145mph while still mainting acceptable low rpm accelaration due to the more agressive cam setup.

My preferred setup however would be FI in which case I would go for 3.08 final dirve ratio (this is only availble with aftermarket 12 bolt rears, not the stock 10 bolt) as they would allow easy 150mph ability. But then again I don't spend every weekend at the track, my car is mostly a road going machine so a broad range of abilities are much preferred, this isn't the case for everyone so pic wisely.

Tips:
-Use D instead of OD for improved gearbox response
-Only roll race from speeds which suit your setup
-Match gears, cam and other mods for intended use

In my sig there's a link to a gear calculator so you can see what different final drive ratio's and rpm limters can acheive terminal speed wise.

Hope this helped

300bhp/ton

Are you serious?

How can anyone not go faster than that in these cars when they achieve 100mph so quickly and easily.

I admire your selft restraint but these are high performance cars and it seems such a shame not to use the performance available.

NxLS1496

iTrader: (1)

Seriously man, i race from a 30 roll and before i know it im up to 110 and i have to stop.

And great post 3bhp/ton as usual. so you are saying if you are going race from a roll its better to have the car in 3rd gear instead of just drive because it will drop faster and be less damaging on the trani??

300bhp/ton

Yep that's right, many modern auto cars have "Sports" mods which speed up the shift firmness and reaction times of the gearbox. Our cars don't have that, but they do seem to be much more responsive if you leave them in 3rd, it prevents lockup and tends to hold it in gear longer even on a lighter throttle.

Plus when you want it to kickdown it should respond quicker going from 3rd to 1st than 4th to 1st.

And yes kicking down in OD at WOT at low speed can be damaging, I'm not cetain of all of the technical reasons (there's been some good threads in the auto tranny forum in the past on it) but it's basically just how the tranny works. 4th or OD is precisley that and over drive and not an entire gear in it's own right.

It's a real shame because it really limits the automatic cars. With an M6 it;s fine you chuck in 4.10's and you have great accelaration, good crusing rpms in 6th and the ability to top 170mph in 5th.

If our autoboxes where real 4 speeds then I'd jump on a set of 4.10's as it would allow high top speed. But being limited to 3rd gear means 4.10's are only really fit for 1/4 mile and stop light to stop light use.

I guess it maybe different for me, but American cars are rare in the UK but if I come across a high performance car it's most likely to be a Porchse, Ferrari, TVR, Aston Martin all of which will go the high side of 160mph. Even the fast Mercs, BMW's and Jags will all top 155mph and I want to be able to play ball with them.

jlashley2001ss

iTrader: (5)

good comments guys!!! good stuff

staringback05

iTrader: (8)

ooo cmon wheres the fun in that, 100 to these cars is like a walk in the park