How I spent my 4th of July.
Well some of it anyway.

The GRS diverter fits OK as is but I wanted to improve it. The front upper lip sets just below the hood sheetmetal and exposes(on my car) the flat edge and I'm sure allows air over the top. Second I wanted room for more air and thought I knew where to get some.

To fix the first bit I needed to cut back the leading edge but I also wanted to bevel it to lead air in better. So first I built up fiberglass on the top which would allow me to remove material as needed from the bottom. The bevel and cut isn't quite finished because I didn't have any heavy grit paper for my sander so I just rolled the edge a bit with 220.

Next I removed a 9 3/4" x 7 3/4" section from the top of the diverter. I coated the bottom of the exposed part of the hood with painters tape. I next installed the diverter. Followed up with installing aluminum tape to form the new chamber.
My actual intent is to use this as a mold to lay in fiberglass. but for now what I have works well.
Based on sampling the depth across the indent I figured there's a 5/8ths" average depth. Using this I have close to 47 cu/in extra room for air. Check my math please. 9 3/4 x 7 3/4 x 5/8.

Using my normal method of cruise until temps level off I did some data gathering today Took measurements all around 2-2.5K RPMs at differeing speeds. Avg inlet was 133, avg. outlet= 105, avg. ambient = 93. Humidity in the 80s. Thermal efficiency is 70%.


Improvements to come.

 

Obe, you're on the right track. Heat reduction = more power. Hope to have some more done, myself, later this week...

 

Shiney.....

Thats looking real cool, Obe. I'm trying to get a grasp of how that sits on the IC. (that is the underside of your bonnet, right?)

Maybe I'm just too distracted by the shiney stuff.

 

20/20 hindsight the picture doesn't show that well. Maybe this will help.
If you look at this pic just imagine the part with the vendor information( sorry Graham) removed.

 

1 thing to remember is the engine moves, north & south, a little better than 3/8". So don't make anything fit too tight especialy over the radiator & the engine.

 

Too true. That's why I've left the basic design of the seal alone.
I've had the GRS over a year and had no issues with interference. The foam is getting a bit worn though.

I'm also running the Powerflex motor mount bushings so movement is reduced.

 

I've always known how much the engine moved, but I never realized the force it had on such a thing as a seal to the bonnet.

I've done a few alterations to my original design because of that.

 

Still working on an under scoop. There are a couple of pics somewhere on this site with the IC plate done.

Obe, so how do you like the mounts as fr as noise in the cabin, if any? Some have said there is a drone?

 

No audible cabin noise for sure. Vibration is quite mild at idle, a little more so with the AC running. At cruise or running hard you'd never know they were there unless you get a little sloppy with a shift. They then do a nice job of pointing out the lack of smoothness

I am only running the 2 large yellow mounts though so maybe someone running all 4 can comment as well.

 

My engine damper increased the vibration felt in the cabin, and like Obehave, especially with the AC running. I guess if you reinforce the connection between the drivetrain and the body, transmitted vibration with increase.
cheers,

 

"I am only running the 2 large yellow mounts."

That setup is what I was thinking

 

It's worked well for me.
Another deciding factor was that the sleeve in the smaller purple units has more clearance around the bolt than I felt comfortable with. This may or may not still be an issue.

 

Ok here you go. The finished proto. And, so far it looks like -8 -10f gain over stock. There are a couple of seals that need to be made so there may be a couple of -degs to go. More pics in the next post

 

The lighter is for scale.

The under hood temps seem cooler since the bottom of the plate is open. It is in the mid 70s today however on cold days, low 30s, it still gets pretty toasty under hood.

I'll need to run some 30-40mph and 60-80mph tests for under hood temp. I have an Alta diverter on the way to do some side by side next week.
For now, it looks like it's working well.... For $12 worth of materials & 8hrs.....

 

Nice

Took me a bit to figure out the hole in the top

 

I do have a plug for it ( like it realy needs 1 ). If this contraption works like I think, I'll make 1 out of CF ( 1 piece - it will look boss ).

 

stevecars60, looks real good, I have my card board patterns cut out but haven't gotten past that, you beat me to it.

 

Hey, good luck with the project. Send pics when you're done

Right now the Alta diverter is on & it looks like the under hood temps are quite a bit lower than the stock unit.....
Obe needs to jump in with his result...

 

Doing some finishing work on it. It's workable but ugly. My first attempt at working with fiberglass so it was pretty rough
Lot's of smoothing and blending.

Did go on a MINI run today though. Didn't log anything but did keep an eye on outlet temps and I'm more than happy with what I'm seeing. Nothing revolutionary but definitely an improvement over what I had before I started doing all the diverter mods.
I'm also going to play with some new materials for the seals. I have some closed cell foam that is a higher durometer rating than what is currently on the diverter.
The tinkering contunues even if it's just for the sake of tinkering.

 

Obe, any under hood temp that is lower is a good thing. You may find that getting a good controled enviroment to test with is very hard. Key word - controled.

In this case, the under hood scoop, I'm looking for better air to the IC & #1 heat reduction under the hood. If #1 works, the rest will will follow. Bottom line, in this case, I'm using a simple gauge to measure under hood temps below the IC ( not much control but you can get a big picture average of where you are going )

 

Been there almost done that. My cheap gauge only goes to 150º, my good gauges are the ones in the inlet and outlet boots. Carefully watching and measuring those 2 points will net me the information I need.
If you think about how thermal convection works temps for the air under the IC may actually rise if you're drawing more heat out of the IC at a particular flow rate. This is really the realm of a flow bench and not some gauge stuck under the IC that will be very much effected by the surrounding metal. You would really need to isolate just the air for proper measurements.

That said I've played with my cheapo gauge placement all over the engine bay. In a nutshell if you're going over 25 MPH you're pulling good air through the engine bay. It would be very hard to differentiate a tiny delta that could just as well be affected by head wind, tail wind, etc.

To me measuring I/O IC temps is the best I can do on my tiny budget.

One thing that occurred to me last night, very subjectively based on recent observations, is that I wish I had made measurements on a return to stability time.
Bear in mind I watch my I/O gauges a lot.....too much... and one thing I've noticed about my recent experiment is that thermal efficiency really hasn't changed but the system seems to recover better. To me that's very important. I cannot give data to support this so ...don't ask It is something to consider and may be something the DFIC does better than the traditional IC. Pretty tough to measure and compare though.

 

"Bear in mind I watch my I/O gauges a lot.....too much... and one thing I've noticed about my recent experiment is that thermal efficiency really hasn't changed but the system seems to recover better. To me that's very important. I cannot give data to support this so ...don't ask It is something to consider and may be something the DFIC does better than the traditional IC. Pretty tough to measure and compare though."

This is the whole point, Air flow & efficiency. There's no doubt the DFIC is the best ( other than running your AC out there ) but as a whole, if the system recovers faster at, somewhat, low speed, it's a good thing & the experiment works.

The Alta diverter was on the car all day yesterday & it is a vast improvment over stock as far as recovery. Tomorow it will be hotter so I'll run the contraption. For a temp gauge I'm using an SW water temp, goes up to 280. The probe sits right at the D rear of the IC. The control is the hard part. accurate #s on different days....... still better than stock across the board

 

Under steady cruise state...I've seen the DFIC bring the temp down to under 10F difference against ambient...

I expect this can only get dramatically better after I install M7's new hood louvers later this week

 

They'd look nicer if they weren't setting proud of the hood surface. The purist in me likes to see them punched in the metal the old fashioned way.
Just a weeeee bit more expensive though I'm thinking and not a DIY.

Curious to see the results

 

Wouldn't those work well in the snows of Chicago winter