Power run in 3rd or 4th whats difference

[Tim-dietrich]

Been reading about dynos etc and people were saying that the power run on a dyno should be done in 4th in our cars and not 3rd why is that.

Reason im asking is because i noticed on my dyno sheet the power run was made in 3rd will put up a picture please comment on anything else you see with the dyno sheet.

Cheers Tim

 

[07GTS]

are u sure is 3rd usually it takes 4th to do over 200kph might have 3rd just in the data

 

[monstar]

Yes Tim there's usually a different shape and output numbers for a third gear pull. For whatever reason the chart seems close to 4th, and looks credible.

 

[Tim-dietrich]

Oh yip so there would be a different power curve if that was done in 3rd. By looking at that dyno graph do you reckon there would be any gain from changing the pod intake to a otr if so what kind of gain do you reckon itd make. It is a auto by the way. And the temp says 25 degrees Celsius on the sheet i take it thats the intake temp

 

[monstar]

I can't tell by that graph for a number of reasons mainly because it is not a real sensor log of pod vs OTR nor actually what your engine is making. ie the PC connected to the dyno calculates and graphs what your engine would make at 15.5°C and 0% humidity given the prevailing 25.2°C and 35% humidity.
But yes the benefit of an OTR is cooler air at speed, which is offset by hotter air in traffic - wider IAT variance - OTR vs pod temps may be +/- 20° for and against OTR vs stable and cool delivery via pod.
The 400lb Gorilla in the room is 12.0 AFR at peak RPM, like I mentioned previous that's leaving too much on the table for no good reason.

 

[Tim-dietrich]

In theory then with a otr it gets all heat soaked in traffic and makes less power as soon as you punch it from standstill?

The pod intake makes more stable intake temps that dont get as cold but it doesn't vary as much, wouldnt the optimum idea then be to add some ducting from the front bumper to the pod style intake.

And what your saying is that its to rich up the top end? Surely there is a reason for the dyno operator doing that as the guy that tuned it specializes in late model holdens n fords.

I really appreciate your knowledge there are some really talented knowledgeable people on here, i feel like we are behind in new zealand prime example everybody sells exforce exhaust and they think its top quality. If i could do it again i wouldnt have spent $2600nzd on a full exforce exhaust

 

[07GTS]

the longer a tube is the more the air going thru it will heat up with the otr even if it gets a little hot the air spends less time going thru it so it isnt affected as much, what i done with my otr was put a layer of heat mat under it between the radiator and it stops most of the radiant heat

 

[NU13]

I just got home from having a cam install done at HBR. Mine was done in 4th.

 

[Tim-dietrich]

I just got home from having a cam install done at HBR. Mine was done in 4th.

What do you think about your cam is yours auto or manual. He seems really good to deal with. What did your cam install cost he quoted me $3000 for cam,springs,pushrods,install and retune.

And just quoted me $250 for touchup retune after fitting otr but im unsure if spending $850 for otr and retune is worth it

 

[Tim-dietrich]

the longer a tube is the more the air going thru it will heat up with the otr even if it gets a little hot the air spends less time going thru it so it isnt affected as much, what i done with my otr was put a layer of heat mat under it between the radiator and it stops most of the radiant heat

Yes that definitely makes sense really is a no brainer to go to otr then as its so short it hardly has time to heat up and surely once the cars moving even at say 20kph surely the intake temp starts dropping quite alot has anybody watched this on a laptop is it possible to watch it in real time