Just to add to that if you are interested I’ve run my car a fair bit without the rubber fillets and the inner wings are very dirty where the airflow is going in there rather than out the rear of the bonnet. I doubt anything would be as effective as those bonnet vents in this post though.
GR Yaris WRC bonnet vents to reduce heat issues?
- Thread starter 6mt
- Start date
Istiban
Devoted member
- Mar 5, 2023
- 97
- 170
So, not sure I'm adding much to this thread but I brought a little temperature logger from Amazon to log the under bonnet temperatures with and hopefully after having vents fitted. I installed it under the bonnet bolted to the strut brace and I got some interesting results.
Firstly, when the car is moving the under bonnet temperature are basically ambient at anything over 20mph. The temperature starts to rise when you stop but does take a while 10 minutes and it's up around 45DegC so rising about 3DegC per minute whilst stationary. It peaked at around 45 to 47 DegC maximum pretty consistently. It then takes a few hours to return to ambient unless you drive then it's basically ambient within a minute again (under the bonnet) not engine temps.
I then tried without the lagging or those little plastic trim pieces and it was basically the same as before so no benefit to removing these other than evicting the mouse that was living in the bonnet isolation which I'm guessing is for noise reduction and housing mice!
I'll keep logging and report again after fitting some bonnet vents, although I suspect these will have little effect on the under bonnet temperatures when moving but may reduce lift at high speeds?
Istiban
Firstly, when the car is moving the under bonnet temperature are basically ambient at anything over 20mph. The temperature starts to rise when you stop but does take a while 10 minutes and it's up around 45DegC so rising about 3DegC per minute whilst stationary. It peaked at around 45 to 47 DegC maximum pretty consistently. It then takes a few hours to return to ambient unless you drive then it's basically ambient within a minute again (under the bonnet) not engine temps.
I then tried without the lagging or those little plastic trim pieces and it was basically the same as before so no benefit to removing these other than evicting the mouse that was living in the bonnet isolation which I'm guessing is for noise reduction and housing mice!
I'll keep logging and report again after fitting some bonnet vents, although I suspect these will have little effect on the under bonnet temperatures when moving but may reduce lift at high speeds?
Istiban
It should make the cooling package more efficient as the air going through the rad can leave easier. If it improves the flow enough the intercooler will work better as well. Toyota have put them on all the R5 cars with a similar shape and engine so it should be successful.
any news on this
Do you also have to get permission for a different style of haircut? Only asking because I think we are being conditioned to always seek permission for everything we may want to do. Because rules. There is a good book about what this leads to. 1984
Michael Knight
Totally Hooked
Better to ask from your MOT-person instead of seeking tuning guidance from a fictional book.
If someone from germany is interested in hood vents with TÜV, SpeedEngineering has some that I just fitted to my car not too long ago.
They may not be "WRC"-Style big, but they are 100% functional and have been tested multiple times.
It also makes the car much calmer on higher speeds since the hot air is exiting through the vents but not the underbody. Personally, I can feel the benefit starting at around 50km/h-ish (31mph).
They may not be "WRC"-Style big, but they are 100% functional and have been tested multiple times.
It also makes the car much calmer on higher speeds since the hot air is exiting through the vents but not the underbody. Personally, I can feel the benefit starting at around 50km/h-ish (31mph).
Last sentence is physically near impossible. Confirmation bias is strong
These ones:
Universelle Haubenentlüftung für die Motorhaube - SPEED
Neben der Rennsport-Optik hat dieses Bauteil sehr wesentliche Funktionen. Die Reduktion der Temperatur im Motorraum. Ab JETZT im SPEED Shop !
www.speedengineering.de
How is water ingress, is it in a 'safe place'? Is there a document where to place them for TüV?
Last edited:
Michael Knight
Totally Hooked
with current skid plate setup stock cars underbody aero is somewhat "destroyed" but didn't notice any difference in 140km/h corners on race track so maybe the ground effect applies fully to lower cars than GR. but who knows.
Very true, I may add that I drove 6 hours on the Autobahn (a lot of the time up to 230km/h) before having these fitted and 6 hours on the Autobahn after having these fitted so I had a back to back comparison and definitely could feel the change.Last sentence is physically near impossible. Confirmation bias is strong
The hood vent on the left is above the water tank for the engine and the water that goes in there damages nothing electrical and also does not favor rust since the engine bay is also painted in the color of the car.
The hood vent on the right side is a different story tho.
It sit's right above the fuse box and next to the ECU.
The fuse box has no problem with (heavy) rain since it's sealed off and the lid of the fuse box hangs over.
The ECU left of the fuse box is a problem tho, since the connections for the electrical connectors are on the top and water could potentionally leak into it that way and destroy it. A new ECU costs a heck ton of money...
BUT for that case my friend that knows its way around CAD & 3D-Printing is helping me develop a cover for the ECU so not even splash water can get in/on the ECU.
I think it gets delivered within the package when you buy it.
I bought it + installment at their workshop.
They discussed three available locations with me (so the TÜV says "yes").
One location is where I have them now (and its the best), the second one is above the engine (but not recommended since the engine cover provides cooling air for the turbo) and the last one is also on the sides but much much closer to the front of the car (but also not really recommended since the air first goes into the back and then down or up).
Sorry, it was raining the past few days so I could not get good pictures.
I did not forget you
Thanks! Credits for the engineering of the hood vents goes to SpeedEngineering tho
For the front lip I use the one from Prior-Design (GR Yaris Aerodynamic Bodykit) including the side skirts and the diffuser because of TÜV.
I have all three parts of the aeordynamic bodykit lying here but not yet fitted to the car.
Last edited:
BarShushan
New member
- Apr 8, 2024
- 20
- 6
Can we
Can we get some more pics?Sorry, it was raining the past few days so I could not get good pictures.
I did not forget you
View attachment 28332
As long as they're open I don't think they can even really be in a perfectly safe place.Last sentence is physically near impossible. Confirmation bias is strong
These ones:
Universelle Haubenentlüftung für die Motorhaube - SPEED
Neben der Rennsport-Optik hat dieses Bauteil sehr wesentliche Funktionen. Die Reduktion der Temperatur im Motorraum. Ab JETZT im SPEED Shop !
How is water ingress, is it in a 'safe place'? Is there a document where to place them for TüV?
However they'll soon be selling these pieces (still a prototype so far!) to block off the vents.
I think that's good enough of a solution to really be able to consider them..
I haven't found a guide for placement though.
BarShushan
New member
- Apr 8, 2024
- 20
- 6
How's the temps after the install? Any change?
Hey, sorry for the VERY late response, I wanted to gather more data before commenting.
What I noticed over the past months was that the oil/coolant temperature is not better vs. no hood vents.
BUT(!) I was able to notice that the engine felt more 'alive' if that makes sense.
Its like if (because the hot air exists the engine bay properly now) the engine has some temperature 'head room' to feel more alive.
Maybe its because I run the OEM air intake which inhales the warm engine bay air when going over 4000rpm.
Now with the hood vents, I think that the air intake does not suck in too much hot air.
