After a few minutes of driving I'd notice a drop off in power on my new 2K3, especially "torquiness". With temps hovering in the mid 90's I figured I'd help the motor cool down more efficiently and removed the thick plastic engine cover. Before doing this the intake manifold would get VERY hot to the touch - I guess since it was almost halfway covered snugly by the engine cover. Now after drving aroung and letting the motor get up to operating temp the manifold is noticeably cooler. I also added RedLine water wetter (cost about 10 bucks) to the coolant.

This has made a noticeable difference in performance especially after the motor is up to operating temp.

 

i was thinking about taking mine off and making a sheetmetal cover that covers less of the intake. thanks for the info now i have a new project

 

Sounds pretty good. It would be great if actual underhood temperatures can be taken. Here's another idea I got from my brother who is a PT Cruiser nut. He got it from one of the PT Cruiser "gurus".

http://www.bstockum.com/toohot.html

 

Any pics of the 3.5 with the engine cover removed? I like the way it looks on but if I get more hp with it off I might have to. Also, which mod made more of a difference? Redline or - cover?

 

I'm not sure since I did both at the same time. The manifold doesn't get NEARLY as hot though so that's got to help.

 

The grand prix guys do this a lot since the GTPs are supercharged, that supercharger gets pretty hot and transfers the heat directly to the throttle body and intake manifold. By removing the acoustic engine cover and the piece of rubberstripping at the back of the hood, engine temps are greatly reduced. I imagine hood flutter would decrease as well since the air flows directly out instead of getting trapped under the hood....

 

Engine cover: already removed
Water Wetter:, already in.

One mod you didn't list: Bypass the TB coolant hose to keep the hot water out of it.

 

You know ive thought about that, but since I dont race I never cared. Wtf is the coolant going into the TB for anyway, I still dont see any reason for that

 

How do you do that?

 

Coolant goes into the TB to warm it up during winter months so you dont get icing.

To block the coolant, all you need is a machined phenolic TB spacer, which will do 2 things. (this is how its done on the gtp, the plumbing might be different on the max.

1. Block the hot coolant from entering the throttle body,

2. Isolate the throttlebody from the intake manifold so heat transfer will be much less. A cooler throttle body is a happier throttle body. With a lower intake air temperature your engine will run better.

 

Bypassing is very upfront and simple. There are two coolant hoses on the lower portion of the TB. One pumping it in, and out the other. Your just basically gonna connect these two hoses together from my understanding. Just need a fitting and two small clamps and I think the hoses are more then stiff enough to stay put, but if not something to hold em in place

 

I remember reading the SENTRA guys always did this mod, but i heard the side effects is during those cold winter months...

ED

 

 

Im in AZ what winter? I dont think its a hard operation. In just thinking join the hoses together and thats it, and when winter comes connect again. No big deal Matt what do you say?

 

guess this is next on the list and cheap too

 

Redline water wetter claims a minimum of a 10 degree drop in engine temp after added to the coolant system...I used it in my 92 accord way back in the day and noticed no benefit....

the 3.5 runs quite hot, so I'll try it again...

 

A phenolic spacer is a waste of time. Like Hitman said you have two hoses conencted to the TB, one in and one out. All you have to do is remove both hoses from the TB then remove one of the hoses from it's feed. Then take the other hose and connect to the other feed or return. Basically you will have a coolant loop that does nothing. I have done this on almost every EFI vehicle I have owned (starting with the SE-R) and never noticed any side effects at all.

 

No side effects, good or bad?

 

No matter how hot it gets here, even in heavy traffic, my temp gauge never goes past the half way mark. Does this sound right??

 

For a Nissan yes. The temp can still vary 40º within that halfway point and not show you.

 

I want to buy the engine cover if you guys are not going to use it. To hell with engine temp and power, I cruise with my "MAX" anyway.

 

I'll bite slag... where might one find this "machined phenolic TB spacer" to do this mod??

 

I have a 3.0L engine with the AE engine cover, granted it's not nearly as big as the one on the 3.5L but would it still help? And where would I find these hoses on my 3.0L so that I might bypass?

 

I took off my engine cover to look, with it off it isn't pretty. But if I can get better performance i'm game and it will keep the cover in good conditon too. What about cleaning the engine with the cover off?????

 

I don't have one. I'm simply saying that we used those on the grand prixs. I havent had my airbox off yet or looked at the throttle body setup on the maximas so I dont even know if this is feasible or would even work on this car.

 

I haven't even looked at the setup but for the guys that live in parts of the country (world for that matter) that have cold and hot weather, could a bypass line be setup with a couple of valves so that you can either let the coolant go through the TB during cold weather or bypass the TB in the summer months?

 

is there a proven hp gain or should i say lack of losing hp? or does it just lower the temp.

 

I dont think any1 is gonna do this mod and then go dyno it to see if they got a 0.X hp gain. How much gain is there is but think of it this way. You are eliminating a 180+ degree heat source running through and heating the TB. In term cooling the intake charge, cool the intake charge and you get more power

 

I was thinking of soemthing exactly like that - although you wouldn't want to shut the flow off fully during summer months - just 90% closed or so to keep just a little coolant flowing at all times through the TB coolant passages.

 

I was going along the lines of 2 valves. One for the original line and adding an additional (bypass) line with another valve. This way you can you can valve out the one to the TB and valve in the bypass around the TB to keep the coolant flowing and vice versa.

 

Those hoses do nothing other than feed that TB. You can plug them up if you want and it will effect nothing.

 

Removed valve (i mean engine cover, just testing you guys) cover -easy
Rerouted coolant lines - a little trickier for an inept mechanic like me but still pretty easy.
Now I just have to find water wetter.

Has anyone removed the weather stripping on the back of the hood? I'm wondering if it's easy to put back if need to.

 

 

Valve cover Put that back on
I hope you mean the engine cover.

 

I just took it one step further and air cooled my cams and valves. Runs great, just makes a little bit of an oily mess.

Yeah, I meant engine cover, not sure how I made that mistake. Oops

 

Never heard of that be4

 

What makes you say that? MobileTek in TX is still sizing & testing but supposably will have dyno's that say otherwise.

 

 

For those of us that rerouted our throttle body coolant lines, is it necessary to replace them in the stock configuration for the winter?

 

No .