Brettus

iTrader: (2)

While doing testing of different tunes (using powermod piggyback) recently I noticed some irregularities in the results I was getting . Having read here that "heat is the enemy of the rotary" I decided to check this out .

First up I should say that these tests were done on a cool day (13 deg C ambient ) so It was easy for me to get the engine hot then cool it down again quickly. To get it hot I just had to sit with it idling for several minutes as the fans don't come on till way too late (as it turns out )

First chart shows 4 runs I did in this order
1/ Cool 1 (coolant temp 84 deg C)
2/ Hot 1 (96 deg C )
3/ Cool 2 (85 deg C )
4/ Hot 2 (96 deg C )
Have included intake air temps on this chart . You can see the first run had the lowest intake air temp as engine had only just reached operating temp & air duct was still cool.


Second chart shows mass air flow - note the difference for the first run where intake temp was lower .

Results :
0.5 s slower from 75 km/hr to 160 km/hr in 3rd gear ! This is a bigger difference than what I got with tuning !
This proves (to me anyway) that a hot engine produces significantly less power than a cool one .

Air temp did not seem as big a factor but looks to affect the result nevertheless.


So :
Mazsport cooling mod here i come !!!
Also : think the RB cold air duct is worth having .

Jax_RX8

That is why I added the Mazport Cooling Mod - great addition for no heat-related power loss and long engine life.

neit_jnf

pretty cool how the mass flow looks like a hp dyno chart with the 2 dips and everything!

mikeschaefer

Brettus have you done the throttle body coolant mod?

Brettus

iTrader: (2)

Yes - I blocked the coolant flow with a plug .
Why do you ask ?

mikeschaefer

Just so I can better understand your results

Brettus

iTrader: (2)

would be interesting to know what diff. (if any) that mod would make to air temps .

Brettus

iTrader: (2)

Just found this on the rotary extreme website to add more weight to the argument.
Runs are back to back to show the effect of heat soak on hp.

http://www.rotaryextreme.com/rx8dyno.html

swoope

iTrader: (5)

yup,

it takes a lot of time to get rid of one heat soak cycle... you will enjoy scotts cooling mod.

beers

RX8PDX

Thats because they dip for the same reason... whats the name of it, the variable intake thing.

So besides the cooling temp mod, what else can be done?

Would aftermarket oil coolers help? Or could a better radiator help more?

Nice experiment, the data is good to know.

nycgps

iTrader: (1)

Do you guys think It would be about the same if I just do the RB's ECU reflash ? since they turn the fan on much earlier than stock computer.

Brettus

iTrader: (2)

yes - absolutely .

Nopstnz

I added the mazsport cooling mod as well but my butt didn't sense any increases. Hopefully it will just benefit in the long run.

Brettus

iTrader: (2)

you should not expect to feel anything . It will only be on the odd occasion that your temp would be high enough to give you the power loss eg. after idling for 5 mins or so.