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My Radiator block and Hot air intake modifications.

There is a wealth of information on this site contributed by knowledgable and enthusiastic members worldwide. Both these mods have been done before, and in depth, but I have decided to document my simple versions for the benefit of others who may want to make these relatively simple changes. It was important to me that my mods did not permanently change the car, so both can be removed in a short time if I needed.

The info in this post applies to my two UK Honda Insights, your’s may differ, so check everything before you begin. I used a ScangaugeII from http://www.scangauge.com/ to monitor the coolant water and air intake temperatures in my vehicle. This helps provide some reliable data, and improves on the Honda water temperature gauge which is very unhelpful.

I'll start with the Radiator block modification. The Honda Insight engine is so efficient that in cold weather it does not develop enough heat to warm itself or the occupants of the car properly. Wear is increased in the engine due to this reduced temperature, and little heat is available for cabin heating. This leads to less than optimum fuel consumption. This simple mod is hugely beneficial, especially in cool/cold climates, it has been shown to produce a significant saving in fuel, and a shortening of engine warm up time. I highly recommend it.

It basically consists of a thin piece of blocking material inserted between the water cooling radiator and the air con radiator. This reduces air flow through the water radiator and engine compartment, improving efficiency.

I used some 2mm lightweight plastic sheeting for my version, it is easy to work with a stanley knife, and it is less likely to damage the radiator on insertion, as it's fairly soft. You can use whatever you like, but lighter is better, don't forget it must be able to stand about 100C without melting.

The block can easily be removed when the hotter weather arrives or when the temp gauge indicates a problem. I took mine out for 3 months during the summer last year. It was in situ the rest of the time.

Here's a picture of the general shape.

http://www.solarvan.co.uk/insight/radblockcut.jpg

A picture with the mod half inserted.

http://www.solarvan.co.uk/insight/radblockinsertion.jpg

And fully in position with little tab sticking up for easy removal.

http://www.solarvan.co.uk/insight/radblockfin.jpg

The sizes I used were

Overall Width 40cm, Height of main area 25cm, height of tab at end 13cm, width of tab 3cm.


Onto the Hot air modification.

This is more tricky, but again has been shown to produce useful results. The Manual Insight has a lean burn feature which works better at higher temperatures. The hotter air being drawn into the engine reduces cylinder charge density and improves combustion effeciency, leading to improved mpg. With an increased air intake temperature it has been shown that the lean burn window widens, and it is easier to maintain in general.

There is not much spare heat in the block water cooling system, but there is a useful amount of heat going to waste via the exhaust system. The catalytic converter requires a certain amount of heat to operate properly, so we have to be careful how much heat we remove if we are using a pre-cat hot air mod.

UK Insights have a normal down pipe from the back of the cylinder head until it runs into the cat, which is mounted under the car in a tunnel. US ones seem to have a cat in this down pipe section. I decided to use the hottest and longest bit of pipe I could find, which is this down pipe area, it is also fairly free of obstructions, and there was enough room to get my mod in position.

These photos show my finished mod in postion on the down pipe from the cylinder head. (I need to trim the jubilee clips!)

http://www.solarvan.co.uk/insight/hotairfin1.jpg
http://www.solarvan.co.uk/insight/hotairfin2.jpg

I decided to duct the hot air into the normal air intake system using the resonator air inlet point on the underside of the the right hand air inlet hose. This is a 44mm 1-3/4" inlet, and I used 125C rated lightweight rubber ducting hose for my mod, so it fitted straight on without problems. I got it from RS Components part no 399-0675 Ducting high temp Superflex Calor 45mmx5m.

Ducting the hot air in via the resonator point has the benefit of allowing you control of the air being drawn in, and the resulting intake temperature, by simply blocking or partially blocking the normal air inlet.

http://www.solarvan.co.uk/insight/airintakeblocked.jpg
http://www.solarvan.co.uk/insight/openinlet.jpg

Above photos show my normal air inlet completely open and blocked, I just used duck tape for this, it can be removed in seconds. The blocking of the normal inlet forces all the engine air to be drawn in via the resonator port, and my hot air mod. Partial blocking of the main intake gives a mix of hot and cold air, leaving it fully open results in about a 50/50 mix of hot and cold air. Just adjust it until you get the temp you want.

With the full block in place, and all air via my intake mod, I am seeing an increase in air intake temp of about 15C, with ambient temp here about 9C at the minute, this moves it up to 24C and a much better lean burn operating window.

http://www.solarvan.co.uk/insight/scangaugereading.jpg

The Insight exhaust is made of Stainless steel, so I used a perforated sheet of 0.9mm stainless steel for my mod, and stainless steel 80-100mm jubilee clips to avoid reactions/rust with different metals. Use as thin as you can get away with to keep weight down. The photos below show the mod at various stages as I built it up.

http://www.solarvan.co.uk/insight/hotairmod5.jpg
http://www.solarvan.co.uk/insight/hotairmod4.jpg
http://www.solarvan.co.uk/insight/hotairmod3.jpg
http://www.solarvan.co.uk/insight/hotairmod2.jpg
http://www.solarvan.co.uk/insight/hotairmod1.jpg

http://www.solarvan.co.uk/insight/airtakeoff.jpg
http://www.solarvan.co.uk/insight/hotairmodtakeoff1.jpg
http://www.solarvan.co.uk/insight/hotairmodoutlet1.jpg

http://www.solarvan.co.uk/insight/hotairmodheat2.jpg
http://www.solarvan.co.uk/insight/hotairmodheat1.jpg

And finally ready to install with hose attached!

http://www.solarvan.co.uk/insight/hotai ... nstall.jpg

It's pretty self explanatory, here are the measurements I used.

0.9mm x 22cm x 20cm for main sheet of mesh steel.

44mm 1-3/4" hole cut in center.

There is a cut out at the bottom end to allow for the sensor 35mm x 35mm.

The cuts at the ends to achieve the petal effect are 15mm x 20mm, I then tapped these over to form the ends of the pipe. This is also the bit that grips the exhaust pipe when the jubilee clips are tightenend, so no sharp points please. You don't want to puncture/damage the exhaust. I formed the tubular shape of the mod around some 48mm scaffold pole, when it sprang back it gave me about the overall diameter I wanted.

It's a bit tricky getting it into position, but it can be done from above the car, I did not need to go underneath to install it. Route the rubber hose away from sharp edges and secure it with a few black cable ties. The mod is very discrete if you take a bit of time, and it does not detract from the underbonnet appearance. I shall be making a non perforated sheet version of the hot air mod for my other car, and comparing the two over the summer. I'll keep you updated.

Good luck with your mods. Lets us know how you get on with them, remember we are all learning from each other. I want to learn from you as well.

http://www.solarvan.co.uk/insight/bothcars.jpg

Regards

Peter UK 8)
 

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Pretty ingenious. Nice work, I hope it works out for you.
 

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That's a great post Peter. Thanks. I like your idea of using the resonator input for an inlet! :D Did you go under, behind or over the top of the engine when routing the hose from the exhaust to the resonator?
 

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Discussion Starter #4
Duct Routing

b1shmu63 said:
:D Did you go under, behind or over the top of the engine when routing the hose from the exhaust to the resonator?
I went behind the engine and under/next to the airbox, Looks more standard that way.
 

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I was lucky to find 2 pieces from my vintage VW parts bin that work perfectly. The first piece is a 2" by 24" fresh air hose which appears to be made of a dense paper with a metallic inner lining. These are commonly used on VW cars from the 1960s. A VW of this era uses two 12 inch length hoses but I was lucky to find one that I had not cut in half so it remains 24" in length and was the perfect fit. The second piece is a 2" exhaust coupler that attaches the hose to the intake elbow.

I removed the original intake and flipped the intake elbow backwards and positioned the rear under the battery tray so it faces the rear of the engine. I connected the elbow and hose with the exhaust coupler. I ran the 2 inch hose under the batter tray and placed it between the engine block and exhaust manifold behind the first Cat. It stayed in place by itself and needed no attachment point. I placed a zip lock bag secured with a rubber band over the hole for the resonator. This will allow it to be easily removed when outside temps get too hot to allow for cooler air to be pulled in. I monitor it all with a ScanGauge II.

I like this option because it allows better access to the front of the engine so I can easily remove the oil filter from the top.

I've had this mod installed for a little over 1,000 miles and it has shown no problems with placement or movement. The temps here this time of year have varied between low 40s to high 70s and I am seeing Intake Air Temps from 115 to 125.

I'm sure you could prepare some type of enclosure around the first Cat to produce even warmer temps if you are in a colder climate.

I've attached pictures that I think are self explanatory but feel free to email me should you have any questions.

http://i227.photobucket.com/albums/dd91/atlaw4u/Warm-Air Mod/IMG_0750.jpg
http://i227.photobucket.com/albums/dd91/atlaw4u/Warm-Air Mod/IMG_0752.jpg
http://i227.photobucket.com/albums/dd91/atlaw4u/Warm-Air Mod/IMG_0753.jpg
http://i227.photobucket.com/albums/dd91/atlaw4u/Warm-Air Mod/IMG_0757.jpg
http://i227.photobucket.com/albums/dd91/atlaw4u/Warm-Air Mod/IMG_0758.jpg
http://i227.photobucket.com/albums/dd91/atlaw4u/Warm-Air Mod/IMG_0759.jpg
http://i227.photobucket.com/albums/dd91/atlaw4u/Warm-Air Mod/IMG_0761.jpg
http://i227.photobucket.com/albums/dd91/atlaw4u/Warm-Air Mod/IMG_0747.jpg
http://i227.photobucket.com/albums/dd91/atlaw4u/Warm-Air Mod/IMG_0749.jpg
http://i227.photobucket.com/albums/dd91/atlaw4u/Warm-Air Mod/IMG_0760.jpg
 

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I completed my Warm air mod on my Euro Insight over the weekend. Without a Cat its harder to get heat and Im no metalworker to build the above.

What I did was cut a 6-8 inch piece of flexible ducting and slit it along its length. I wrapped it around the manifold pipe above the O2 sensor and near the top I opened it out further to about 3 inches. I then brought the air feed right up to the opening so its sucking air from around the manifold pipe. I left the Resinator pipe in, but cut the air to it by around 50% so it would draw more air from the manifold area.

So far, Its a good 5 degrees or more above normal when driving on the Motorway and close to 10 degrees in town areas. I've noticed more lean burning especially at lower speeds. Quite an easy mod to do once I worked out a make shift hot air trap. Too soon to tell about MPG gains and it cost around €20 in bits and bobs to make, most of that being the flexible ducting that I couldnt get local in the right size and had to get shipped from Fleabay.

Pics to follow.
 

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I've read some of the similar threads but could not find a general rule of thumb at which degrees and under which driving habits the block should be removed.

Winter temps are between -10 (14F) to +5 (41F) degrees Celsius, summer temps between 25 (77) and 35 (95) degrees Celsius in my area. I mainly drive on the highway with up to 70 mph and Switzerland is not flat. :)

I only want to fit the block once a year, not on a daily basis. :) Are there any recommendations so far someone can share?
 

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I guess we are fairly "lucky" in the UK/ROI that temps go from -5 to +25 and thats a fairly extreme range for us. So this sort of rad block and hot air mod could prob be used all year around. Best to keep an eye on the scangauge though.
 

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Ok, for those who are jonesing for more info and another back to back before and after test. I made a hot air shield and installed it, and will be driving to meet my wife for lunch along the same route i took yesterday. Total of 21 miles, mostly freeway, with about 2 miles of city driving. Ambient temps are 60 degrees. Size of block was taken from another post a couple years ago. It's 17" X 6 1/4" with a tab for quick removal. The radiator is 17" wide, and the 6 1/4" covers the distance from the bottom to the top of the air inlet area of the front bumper. I don't have a scanguage, But the radiator fan kicking on if things get too warm(which I doubt) from reading plenty of posts on the subject. Yesterday netted me 65 mpg's on this trip...today, same trip was 70 mpg. Did notice lean burn was a bit easier to get into today. I suppose as long as things are low 60's and below, I'll leave it in. I did turn my heater on on the way back and noticed it felt quite warm.
 

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... but could not find a general rule of thumb at which degrees and under which driving habits the block should be removed.
There is no general rule of thumb. Temperature and Driving conditions will mandate when the radiator block size you choose will be too much. 205F (96C) coolant temperature is the fans on point and should be respected.

That's why monitoring the ECT (Engine Coolant Temperature sensor) with a scan tool is necessary to establish the "normal", "safe" operating range for the blockage you choose. If you remove active monitoring remember that _anything_ different in your driving pattern can result in an overheat and serious engine damage.


Also see:

http://www.insightcentral.net/forums/mpg-issues/8782-1-6x17-cardboard-piece-10-mpg-yup-no-lie.html

HTH! :)
 

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I did a hot air intake myself. It's a simple flexible aluminium tube from the exhaust pipe to the airbox. The OEM tube at the airbox gets changed by the alu tube.

63 F outside temperature, intake temp with the OEM tube: 74 F.
With the tube installed I've seen 100-118 F, 26-44 F more.
What would you concern the maximum intake temp? I don't want to burn the car down. ;) Is 140 F too much?
 

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@Peter: It's now been 3 years since you created this great "howto", are you still running the hot air intake just as you did from the start, or have you changed anything / improved your setup. ?

Temperatures are falling here, and getting into & maintaining LB. are getting
harder now, so i am also looking at making a hot air intake before temperatures realy takes a drop.
 

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Thanks for the info posted retepsnikrep.

Just finished a 170Km round-trip test drive with a similar setup and all seems well. Outside temp was + 15-17*C and I've got 2.9L/100Km in moderate driving.
 
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