TurboCab

I just want to lower temperature under the hood. My car is turbocharged and will be benefited from this. I’m thinking about the installation of a factory 968TRS hood scoop. Does anyone have it installed? My concern is from water entering the engine bay under heavy raining. Any suggestion will be appreciated. Thanks!

RajDatta

This should not be a problem unless you have an air-filter in the area. If you go fast enough, water will not get in! .
Raj

ehall

Wasn't that vent used in conjunction with a purpose designed IC duct?
You may be better of with a vent type similar to this.

or with the a/c vent style. It'sreally about evacuating the hot air.

Jason Judd

I have that vent installed on my car...it mates with the intercooler as an exhaust vent for the hot air coming off the intercooler. I also got the larger intercooler intake vent in the front bumper.

I don't have the naca ducts that are also used on some versions, though. My understanding is that one of the naca ducts was a cold air intake...Since we moved my air intake to the driver's side lower section of the front bumper, we felt there was no need for that. If I remember correctly, the second naca duct was more of a cosmetic issue to balance out the first.

Although I could be wrong on that point.

Raj, do you know the story on those?

By the way, I'm happy with the setup; and I feel that there is significant heat that is being channelled out of the engine bay because of this exhaust vent.

Jason

TurboCab

Thanks guys for your feedback. The idea that I have is for a Hood scoop from which hot air is suctioned as hi speed air passes over the hood.

RajDatta

Jason, you have it exactly right. The factory turbo S hood will terminate its driver side NACA duct into a special built snorkel connecting to the airbox. This gives the air filter cold air. The passneger side is for looks or balance.
Angel, I am not an aerodynamacist so I wish I could help you. I am sure a few will pop up with ideas on how to do that. Just make sure you know who you listen to .
Regards and a happy new year to you guys.
Raj

TRWright

Stupid question, but do you have all of your exhaust wrapped?

Jason Judd

Not me...how big of an advantage?

Jason

TRWright

Huge! I am guessing by his username that he has a 968 turbo. There is a lot of exhaust to wrap. Header/crossover/turbo hotside/downpipe. Wrapping all of that will take a LOT of heat out of the engine bay. (. . .and also provide a few hundred RPM quicker spoolup.)

TurboCab

Ted:
It is a good idea to wrap the headers and crossover pipe, but the major offender here is the radiator. My intercooler is installed in the fron bumper cover grille, so it will not contribute much. But there is a lot of heat comming from the radiator fans. Things will get worst since I'm in the process of installing an HMR radiator 475, which will remove more heat fron the engine, and consequently will rise the underhood temperature. And YES, my car is turbocharged.

RajDatta

I can see this being much more useful in a race/track car. It makes sense because the factory felt the same way as well. These ducts were only available on the turbo RS.
Raj

Jason Judd

OK, I get to show my ignorance here...once again,

What are the differences between wrapping the pipes and having them coated? I've heard about different types of coatings (Jet Hot?) used on exhaust headers in lieu of wrapping them, I think.

Are they 2 different approaches to the same issue? Or, is there a difference between them?

Jason

flash968

cost and longevity are two i can think of

wrapping is the "old school" trick - it's cheap and effective, but often can shorten the life of the header

coating is a far better way to go, but is a lot more expensive - often you have to start with new pipes

both of them help reduce the underhood temps, but more importantly, they help scavange the exhaust better

TRWright

I was all about the coating at one point. Special Tool did datalogs of a stock header coated and a stock header wrapped. The one with the expensive coating offered very little spoolup over stock. The wrapped one gave him around 150rpm quicker spoolup (IIRC). That, IMO shows that the DEI wrap is doing a better job.

Yes, it can shorten the life of the header because the pipe is going to get hotter and stay hotter. That is really the whole idea.

The ceramic coating sure does look pretty though!

flash968

hmmm - i'll have to dig up the thing i was reading a couple of months ago that showed the exact opposite results - now i get to go try to find that thing again - woohoo - more reading

i've done both, and honestly i can't say i've seen any performance difference - however, i have seen pipes rot out (though not stainless), wraps come apart, and other such issues one can expact with an incomplete application like that - after all, you really can't get the whole thing evenly

i'm not slagging the wraps - they work well - they are cheap - they just don't generally last as long - in a race car, where you are replacing your header every other season anyway (or at least should be), i doubt that it matters