Dyno pulls in 4th

[jp2134]

Just had a few runs done in 4th only because the owner, for some reason, wasn't comfortable with running 5th.
Fine by me just because i was only checking to see if my tune was good.
The car put down 401/338 which i was pleased with. Much better than the run i had in 5th a few weeks ago that did 379/353, with CAI, Tune, Boss IM

Is there some magical equation to figure out what a 5th gear run would look like?

 

[KrisR]

Is there some magical equation to figure out what a 5th gear run would look like?

No, not really. At least in my automatic (and other ones I've seen), a 3rd gear pull makes more peak hp but less peak tq than a 4th gear pull. In 3rd mine made 391hp/326tq and in 4th it made 384hp/343tq. I would guess a manual car would be similar....lower gear = more hp, higher gear = more tq.

 

[jp2134]

I thought your best numbers come from a 1:1 ratio. I would expect both numbers up on a 5th pull.

I really just want to know if that's on par for my mods.

 

[KrisR]

Well actually there is no 1:1 ratio in the A6, so maybe my situation doesn't apply here but I thought I would mention what I've seen.

 

[mechanicboy]

The car put down 401/338 which i was pleased with. Much better than the run i had in 5th a few weeks ago that did 379/353, with CAI, Tune, Boss IM

Torque went down? was the Boss added between the two runs?

 

[jp2134]

No, the first time the tune was bad. He never ran a full run. 379/353 on a 6k run. Had black smoke ervrywhere. 5th gear pull a fee weeks ago.

Got the tune straight and had to go to a different shop. But still using SAE. Ran 3 4th gear pulls almost spitting image to each other. 401/338

M6 3.31's

 

[chadder1313]

I would think not being 1:1 in 4th would net a lot higher number than 401. 1:1 is what you should do a dyno pull in.

 

[itSSlow98]

Add about 8rwhp to it and theres your 5th gear number.

 

[jp2134]

Add about 8rwhp to it and theres your 5th gear number.

So then the tune looks pretty good. I think I've seen most people with the same mods and no cats put down around 420. The torque numbers look horrible in 4th.

 

[Tyler72]

The reason some tuners don't like to do it is because its a long hard pull that puts a ton of load on the engine if starting from a lower RPM. When I dynoed my own personal car, I'll did 2 or 3 pulls in 4th gear to check everything, then made a final pull in 5th starting at a higher rpm to get better peak numbers. 8-9 HP more is about what you'll see.

 

[SCalla1384]

I dynod in 4th gear, made 419rwhp and 373rwtq.

5th gear with 3.31's was about 190mph. And only made 410rwhp but made 390rwtq. The tires were wrinkling up top. I have 275/60 15" NT555Rs

 

[jp2134]

So with my torque numbers extra low, I'm thinking the torque management needs some loving. Then I guess that should bring both numbers up.

 

[D.T.R]

Definitely didn't know the 6R80 doesn't have a 1:1 gear. Interesting.
And yeah some tuners don't like doing pulls in 5th not only because it is a big load on the engine, but also the MPH you'll be running on the dyno. Some max out before 200mph.

 

[SCalla1384]

So with my torque numbers extra low, I'm thinking the torque management needs some loving. Then I guess that should bring both numbers up.

I'm not sure exactly what tq Managment does? I thought it just cut fuel if it saw the clutch slipping.

But, with the short runner boss intake and only 4th gear on the dyno, that's why the tq is low. I think usually it's 360-380rwtq with a boss intake. Give or take..

 

[dirtyd88]

The reason the car makes more power but less torque in a lower gear is because of the ratio of the trans gears. Basically the car is doing less work (torque) thanks to the higher ratio to produce more work over time (horsepower).

It would be nice if someone could find some times of mathematical relationship between the two, but I think there would be too many factors and possible unknowns.

 

[jp2134]

I'm not sure exactly what tq Managment does? I thought it just cut fuel if it saw the clutch slipping.

But, with the short runner boss intake and only 4th gear on the dyno, that's why the tq is low. I think usually it's 360-380rwtq with a boss intake. Give or take..

I know it makes less tq, but thats 20-40 less TQ on a 4th gear pull. Would it actually make up that difference in 5th?

 

[dirtyd88]

I know it makes less tq, but thats 20-40 less TQ on a 4th gear pull. Would it actually make up that difference in 5th?

Definitely. You are making to motor work harder to deliver that power to the wheels from the lower ratio. Therefore you gain TQ and sacrifice a little HP since you are taking more time to deliver that power.

 

[jp2134]

Definitely. You are making to motor work harder to deliver that power to the wheels from the lower ratio. Therefore you gain TQ and sacrifice a little HP since you are taking more time to deliver that power.

So my HP doesn't look good then? I just need to go make a run in 5th somewhere.

 

[dirtyd88]

So my HP doesn't look good then? I just need to go make a run in 5th somewhere.

It will definitely be under 400 in a 5th gear pull in close to the same air.

I would do the 5th gear pull if you can. But it's entirely up to you to do so.

Is your location Fredericksburg,TX? The heat and humidity are probably contributing to low numbers too.

 

[jp2134]

I'm in VA. The first time i was on with the crappy tune it made 354tq in 5th. But i thought it would also put down more HP on the longer run.