Cost Efficient Mod's That Won't Void Warrenty

[bstockum]

Nice work Strange.

This work was done over a year ago with an 5 channel data recorder sampeling temps all over the engine compartment. Graphs and pix are posted on my website.

Great to see someone else making the effort to fan the flames!!

check it out at; http://www.bstockum.com

Enjoy! ... Bob Stockum

Highly DeveloPT Cruiser

[strangelove]

Hey Bob,

I found your site absolutely amazing. Seems you have done your reaserch and ten some. I was wondering since you did these tests last Aug. if you had an early version of the stock PT Turbo and stock intercooler, or if you were running a Hahn turbo etc? Also have you done any permanent modifications to the hood to allow for heat venting, inducting? My main concern is filtering out debry and water. I was thinking of constructing a large filter, and maybe fabricating a carbon fiber water trap to channel water away from the engine. Maybe I need to look closer at your site, but there is a lot of info there for right now.

I hope that your are not mad about me adding part of you website here, but I thought it would be helpful for others interested in this subject. By the way Bob Rocks<img src=icon_smile_question.gif border=0 align=middle> the following comes from Bob's site http://www.bstockum.com/toohot.html

quote:First I removed the rubber strip from across the top of the engine bay. Just the back piece! It is not glued, it just pushes into place. Start at one end and pull up gently.
I had a spare rubber shock mount, so I clipped the "tail" off one of those Goofey big plastic rivets that Chrysler uses to hold body parts on with. Then it screwed into the hole in the rivet. I noticed a screw about in the center of the engine bay that holds down the plastic grill around the windshield whipers. I removed the screw and the pop in threads too. The 10-32 threads twisted in perfectly! The total height of the new hood support I just made is 1 1/4" off the tray. You now have a full 1" openning all the way across the top of the hood to let out hot air. The slot is so far under the back of the hood, you can hardly see it. After driving a while, now stop, turn off the engine so the fan doesn't run and hold your arm over the back of the hood near the glass. Feel the hot air? ... That is just from convection, the hot air rises and pulls cool air into the engine bay from the bottom, just the way we want it. On the highway, the air rushes out! I am going to do two things.
Tape little pieces of string all over the general area to see how the air flows at speed, because at some speed, the pressure at the base of the windshield may be greater than the air comming in through the grill and under the car. The NASCAR cars make their engines breath at the base of the windshield because it is the cleanest air and under a slight pressure. This found in wind tunnel testing! I can't afford to rent the NASA full scale tunnel for a day, but I can check this out on my own.
Â* I will also put the rubber strip back and check the under hood temps with a portableÂ* temperature gauge I have. Driving, sitting in traffic, shut down after driving, both with the strip and after removing it. I will post the results in a few days. I am not recomending that you do this until I can check it out fully. Others have done this and gotten scared when they were told that the air might flow back in the slot, at the back of the hood, at speed. ........ Does this automaticly mean it is bad? To some, that is all the info they need to assume it is a bad thing. I am not so sure, but I will find out and let you know.
Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â*Â* Â*Â*Â*Â*Â* Thanks for stopping by!Â*Â* Bob,

Â*


Here is the temp graph Bob ran with weather strip on. For details go to Bob's site http://www.bstockum.com/toohot.html





Here is another temp graph Bob ran with the weather strip removed. Comparing the two graphs you can see that without the strip the engine bay stayed 20 to 25 degrees cooler. I have seen the same results since I have been measuring temp while commuting to work during the day.
<img src="http://www.bstockum.com/town_nostrip.jpg" border=

[strangelove]

sorry here is the second graph without the weather strip.

[2sb]

Cool fresh air flowing in from windshield base isn't bad. Cool water (rain, car wash, etc.) hitting a hot exhaust manifold is very bad. Check the cost of a new manifold/turbo before leaving the weatherstrip out.

[earringboy]

...I've been a car enthusiast for years and an engineer by trade. I now own and operate a custom car speed shop. I learned years ago about venting through the rear of the hood. I have done this modification on virtually all makes and models of cars and usually it's the first thing I do. Hot air is actually sucked out from the engine compartment by the venturi created by the air flowing over the windshield. It is harmless with the only drawback being that it also allows hot air to be drawn into the passenger compartment by the hvac system, the base of the windshield is also where the air intake is for the hvac. What we have done is to just leave a short ,18 inches, piece of the weather-strip on the passenger side. It stops the vent air from feeling like an oven and smelling like a hot engine in the car. Very little water enters through the opening because the turned up lip stops it and with the PT it is several inches toward the front...An added bit of info...finish off the sharp edge that's left exposed with a piece of door edge guard, either black or chrome and it will look good and won't cut you up while cleaning the car. We also have experimented with various opening sizes...the result is anything over about 1/4" is no gain. The amount of air coming out is in direct relation to the speed of the car...so open the sunroof and run up to about 100 mph and just stick about 1/2 of your finger out and see just how much air is being pulled out...We also have found that with small displacement engines they never get to operating temperature in extremely cold weather, they actually become 'air cooled'. With the PT we get multiple positive affects from this no cost modification...it is one of the few cars that actually have a complete seal all around the hood..so the venting out the back is quite efficient...just some info for your evaluation assistance. If you want to look further into it, it also stops the positive pressure from building up under the hood and the increased flow through the radiator is tremendous...Hate to keep rattling on but we also have noticed that in the summer fewer bugs will hit your windshield with the flow of air out and over the glass!

Inferno red GT/R-package/heated seats/rear wing/5-speed

[chasgood_in_okc]

WOW.. Lots of good info earringboy. You to Dr. GT Strangelove. A snow storm messed up my traction control mpg test. Will snow again tomorrow here.
Looking in my airbox I couldn't see where taking the white piece out of the top would help other than removing the plastic ring around it. In the bottom the black plastic tube goes 1/2 way through the box. Couldn't get it apart without breaking it. Got the ole Dremil tool out. Cut a half circle out of the top of the plastic where the air comes out. The air should be going more directly through the box now (less twisting and turning). Could take a pic of it but have no site to post it on.
Will think about cutting the rubber at the back of the hood. Leave it on where the heat&air vent is. Gets real hot here in Oklahoma in the summer.

[strangelove]

Hello,

I have been running Mobil Supersyn 5W-30 for the past week and I have seen a 5 degree drop in engine running temperature. With the added benifit of not needing to let the engine run for a few minutes to let the turbo cool, to prevent coking this is a plus. The average temperature I am seeing during highway driving is 15 degrees f above the outside temp. Still working on the ram air scoops for the undercarriage.

[2sb]

Sorry guys, I think I erred. Visited the the friendly local DC dealer today to look more closely under a GT hood. The exhaust manifold/turbo is probably safe. That large heat shield over it should sizzle any rain that makes it that far in short of a frog-strangler.

[chasgood_in_okc]

I plan on using Mobil 1 5W-30 too. The forums here have lots of good oil info. http://www.bobistheoilguy.com/
Think I will remove the rear hood gasket on the drivers side only. The heat & air vent covers about half the width. Don't care to suck in engine heat during the summer. The engine air intake is on the drivers side anyway.

[Jeff V]

One of the most fascinating threads I've had the pleasure of reading. I am not an engine guy, but I have a question about removing the weatherstrip: it looks like the concern orignially posted about damage to the manifold has been put to rest, but what about drag created by removing the weatherstrip? If we imagine the sucking motion of the wind swooping over the hood will now suck air from under the hood when it didn't before, doesn't that sound like it would slow the car down with all that added friction?

If you haven't cruised Maryland, you haven't cruised.

(unless you cruised somewhere else)