Reducing under bonnet temps?

[TA22 GT]

Hi all,
For those that don't know my Celica, I have a TA22 GT running a 3T GTE. Under bonnet temps have been an issue and so far I have used the HPC coating on the exhaust manifold, turbo snail and dump pipe. Although HPC coatings help, the temp was still too high so I now also use ACL ceramic insert heat shield.

Now thinking about fitting a bag over my turbo as well and maybe even tape around teh dump pipe. Do these bags radiat much heat? Can you touch the outside of the bag when the turbo is hot?
Anyone fitted ceramic type tape over HPC coated pipes?

I have a Garret GT25 turbo, any ideas on where to buy these bags in Perth?

I heard so much about HPC coating and how good it is, but for me its still not the answer....

Cheers,
Simon
http://users.chariot.net.au/~stmezz/celica.htm

[Yian]

Some discussion in this thread.

http://www.toymods.net/forums/showth...ht=underbonnet

[TRAV-KE55]

Heat wrapping the existing piping isnt your answer, all it does is cook the piping to death, i recomend against this, perhaps more heat sheilding, you will always get some heat of that side of the engine! Maybe some more air flow in and around.
Trav

[Rattlehead]

Heat wrapping the existing piping isnt your answer, all it does is cook the piping to death, i recomend against this
Trav

Does that apply to all types of piping? ie. Stainless, steam, mild?

[TRAV-KE55]

Does that apply to all types of piping? ie. Stainless, steam, mild?

Pretty much, it makes the steel go crystalized like and its just to much for it, thats the beauty of HPC coating it stops alot of that heat getting to the pipe as well as a rust proffing!
Trav

[Dangerous Dave]

You should try using ACL Heat Shields.
http://www.acl.com.au/
You can by it as a sheet and shape it yourself. From memory it isn't that expensive and would be worth a shot. These are the distributors in WA
National Parts Pty Ltd (08) 9455 5600
Repco (National Phone room) *133 227
Coventrys (08) 9276 0111
Veales Auto Spares (08) 9356 6666

Goodluck
Dave

[Hybrid]

If you reconsider HPC coating in the future I highly recommend Jet-Hot in Melbourne.

http://www.jet-hot.com.au/

There prices are very good and are one of the most respected coaters in the business.

I had a dump pipe (mild steel) and HKS turbo manifold (stainless) done and the quality was absolutely perfect.

The turbo manifold (HKS) was for a friends SR20 running at HKS GTRS .... 12 months down the track it is still as new with no cracking or any other signs of failure of the manifold or the coating.

The Turbo manifold was done in their Jet-Hot 2000 product which has a temp rating of 1094c, whilst the dump pipe was done in HiTemp Black (temp rating 843c)

[Draven]

another question might be: how much hot air can escape from under your bonnet? if not much air is getting out the back of the bonnet your temps are going to be up no matter what you do to your turbo... have you considered some modifications to release more heat? (either small bonnet vents, chop some of the rubber back there, or the drag-spec super dodgy washers to space the bonnet up?)

[Lambolica]

To satisfy your own curiosity you could try poping your bonnet and driving it like that to see if that improves fair flow in the engine bay and brings engine bay temps down. However this helps the ambient air temp and doesn't help heat soak.

If you notice a decent drop in temp you could try either removing the skid pan to see if there are improvements or modify it so it rams air though the engine bay rather than deflect it.

or alternativly run piping from somewhere that gets decent ram air flow from the front of the car and point it at the turbo.

Once again these will help the ambient temp but heat shields would better help contain heat from soaking through the whole engine bay.

I have seen 1 car that had a tube (if you will) of heat sheilding around the turbo, manifold and dump pipe that sort of exited under the car. to the front of this a ram air pipe was connected so whilst in motion there was constantly air being blown through the "tube" keeping the source of the heat lower.

Other good ones I have seen are using 2 layers of shielding with an air gap of about 1cm between the 2 shields, which seemed to get good results.

My 2c

[TRAV-KE55]

Someone correct me if im wrong please but these are my thoughts.
I would avoid poping the rear of the bonnet up as this will only draw attention with the wrong people, and also the bottom of the windscreen area is a high pressure point on most cars, I know with our old TA22 race car the bonnet didnt clip down properly and mid corner the latch let go, it took speeds above approx 110km/h for the bonnet to start to lift at all and even when it did it was only a small amout, it was interesting to watch, you would be better of putting a front spoiler on the car which will cause a lower pressure under the car and draw more airflow through the radiator, thus more engine bay airflow. The standard splash tray is also desinged to acheive this but to lesser extent. If you have cooling issues this also helps as the radiator gets more air flow through it as the pressure is trying to be equalised under the car. Next time you get a chance have a look at a AU II falcon and check out the big plastic undertray on the front bar about 1 foot under, its designed to help engine bay/radiator airflow.
Trav

[Lambolica]

Yes I should add that I was mentioning pop the bonnet for the purpose of testing only, definatly not recommended for constant driving like this.

I must look at the Falcon undercarrage, I've been looking for a good design to the undertray to adopt as this would be a neater solution.

[JustCallMeOrlando]

I would've thought that raising the back of the bonnet would've stopped by now. Given that the back of the bonnet is a high pressure area, it's not going to do a very good job of removing the air.

[HAVABEER]

could you possibly try fitting a rear facing bonnet scoop?? there's a few sites out there that can tell you how to make your own for pretty cheap.

but i remember someone saying that rear facing scoops can mess up air pressure in your engine bay so it doesnt flow as good as it should or something alon those lines.

something maybe to look into though??

[Dale]

Not trying to be a narc here, but I can't see bonnet scoops or anything (that will double as) aesthetical modifications being the answer for this car. It's a ta22 GT!! And Simon wouldn't be the person to butcher it for performance's sake..

[TA22 GT]

Yep, as Dale says I don't want to modify the external look of the car as I want it remain as it did from the factory.

Theres no issue with the running temp of the engine, just the heat soak makes under bonnet temps a little too high for my liking. Since I fitted the BB turbo, custom manifold etc temps are much higher. But there again I'm also running around 14psi boost compared to 7psi with the old CT20 turbo.

I have tried to pop the bonnet and it does help. I've also thought about removing some of the rear bonnet seal to let more air escape? Or I might be able to cut a couple of holes in the plate that fits under the GT bonnet vents to let some air out. I could do it so it would not be visible from the outside of the car.

The car also has the GT spoiler which is pushing air up into the radiator area, not sure if this is restricting air flow from under the car?

I already have HPC coating done in Melbourne. Its fine, BUT it still radiates alot of heat. I have also put some ACL heat shield over the exhaust manifold which is a great help. Its heaps better than what I started with just hoping to reduce temps a bit more.

Somehow I'm thinking more air flow is the answer, its just a matter of working out how to achieve that without adding a bonnet scoop etc.....

Anyway, thanks for the feedback.,

Cheers,
Simon