Cams and torque myths.

[07GTS]

Give me a PD over a cam any day.

let me know if u ever get hptuners id like to try and fix your cam issues or at least get it better, can sometimes take many hours or days, weeks of just testing to get all the tables to work together which can be why shops don't bother

 

[Immortality]

$2k might buy a cam kit but it's about $6k or more once it's fitted. And won't be as nice to drive, and won't give you the torque a PD will

Guy at work has a VF2/LS3, moderate cam making about 335rwkw with stock converter and diff. The car is fast but it's a bit of a pig, it pushes through the brakes at idle and sucks gas like it's going out of fashion around town. At traffic lights he slips it into neutral waiting for that green.

 

[losh1971]

Mine needs a street tune not the max HP tune it has now. But $800-$1000, when I still need to buy springs and have them fitted along with the trunnions. To do the trunnions and springs is another $800 in labour. So this has all has to happen next year and probably not before April now.

 

[Immortality]

On road tuning off the engine Dyno is only for wind drag.

Bollocks.

Unless the dyno operator can simulate the exact ramp rate that the car will have (depending on car weight and driveline ratio's and wheel diameters etc) the tune could be way off. If the operator has used a very slow ramp rate there could be power left on the table or if he's used a fast ramp rate then when the engine is in the car and can't accelerate as fast as it did on the dyno it will potentially go into spark knock.

The exact same reason why you tune in 3rd gear on the chassis dyno. You could tune it in 2nd, throw a whole lot of timing at it and make a big number but the engine is going to knock when in 3rd under full load (using a 4l60e or equivalent 4 speed auto where 3rd is 1:1).

Fairly much the same reason road tuning needs to be done with care, how often can you run a car out on the road in 3rd gear (talking about an auto 4l60e) or what ever gear 1:1 ratio is for that transmission?

 

[losh1971]

Guy at work has a VF2/LS3, moderate cam making about 335rwkw with stock converter and diff.

Mine has 314rwkw on the dyno but this is little use to me, unless I'm towing my fully loaded trailer heading up the outlet.

 

[shane_3800]

Bollocks.

Unless the dyno operator can simulate the exact ramp rate that the car will have (depending on car weight and driveline ratio's and wheel diameters etc) the tune could be way off. If the operator has used a very slow ramp rate there could be power left on the table or if he's used a fast ramp rate then when the engine is in the car and can't accelerate as fast as it did on the dyno it will potentially go into spark knock.

The exact same reason why you tune in 3rd gear on the chassis dyno. You could tune it in 2nd, throw a whole lot of timing at it and make a big number but the engine is going to knock when in 3rd under full load (using a 4l60e or equivalent 4 speed auto where 3rd is 1:1).

Fairly much the same reason road tuning needs to be done with care, how often can you run a car out on the road in 3rd gear (talking about an auto 4l60e) or what ever gear 1:1 ratio is for that transmission?

What you say is true depending on the Dyno.
Roush Yates have Dynos that can simulate race conditions exactly.

 

[shane_3800]

Mine has 314rwkw on the dyno but this is little use to me, unless I'm towing my fully loaded trailer heading up the outlet.

314kw from a V6 is very impressive.

 

[Immortality]

What you say is true depending on the Dyno.
Roush Yates have Dynos that can simulate race conditions exactly.

I bet they can. The also know the exact weight, drive line ratio and everything else about the car the engine is going into.

F1 teams do the same thing but they all have huge amounts of data and testing time under their belts.

BTR putting an LS1 on the dyno with one of their towing cams has no idea about what the final engine combination will be or what car/application it will be used in. You simply can't create a perfect engine tune for that.

 

[shane_3800]

I bet they can. The also know the exact weight, drive line ratio and everything else about the car the engine is going into.

F1 teams do the same thing but they all have huge amounts of data and testing time under their belts.

BTR putting an LS1 on the dyno with one of their towing cams has no idea about what the final engine combination will be or what car/application it will be used in. You simply can't create a perfect engine tune for that.

But you arr so wrong because the engine Dyno is a tool.
Just because you don't know how to utilize the tool it doesn't mean others fall short like you.

Engineering is dealing with the measurement equipment you have, tribologists have to deal with this yet the arm chair experts here seem to think they know more.
Sadly the only avaliable tool we have to compare our engines is a super flow water dyno.
So we have to make do with the data and the trend in the data prooves my point.
Engineering as much as it is doing algebra it's also translating data.

 

[losh1971]

314kw from a V6 is very impressive.

Where have you been? The VR was totalled early this year. I now have an L98 manual VE ute. The old ute was way easier to drive than my 6L VE.