DIY HAI and heat shield on Saturn SL2 - Gas Savers

Project84 · 07-10-2008, 07:28 PM

What mine consists of is.....

(1) 1 1/2 inch 45* pvc elbo found in plumbing dept
(1) silicone coupler 1 1/2" x 2 1/2inch
3" flex tubing
1" section of 2 1/2" pvc

heat shield is industrial flashing, but you can also buy DIY HVAC stuff in most any Lowe's or Home Depot. You want something thin and plyable.

I removed the old inlet for cold air from the airbox completely; this is where you'll find the IATS or Intake Air Temperature Sensor. Cut a piece of flashing and pop riveted it over the hole in the lower air box. I used caulk to seal it also.

Relocate the IAT sensor using drill, then tap, so that you can still thread it into the UPPER air box to read your new IAT. I forget what size, just match the threads up w/ a good tap.

Remove "resonator" from lower airbox assembly and discard. Reem hole out or use a "hole saw" to make hole roughly 1 1/2" diameter. Put silicone sealant around 45* elbow, stuff it through new 1 1/2" hole. Add coupler to the outside of the elbow (note: I chose an elbow w/ a male and female end- use the female end on the inside of the airbox so that it cannot be pulled through. I then used a 1" length piece of 2 1/2" pvc for rigidity, put that in the coupler, slip flex tubing over coupler and use a large band clamp to secure it.

Guess the length of flex tubing you'll need, and cut. I stuffed mine between the block and oil dipstick tube; just behind the header. I sorta cut it at an angle, not sure why, just seeemed right.

For heat shield, I removed (4) 10mm bolts from A/C bracket @ block. use pry bar and pull bracket away from the block just a hair, stuff your heat shield behind the bracket for the compressor. Up to this point it's all straight forward, after this, you just have to give it a good look over and toy w/ the shield to custom fit it. Once I got mine cut to fit how I'd like, I marked where the bolts went through and remove the heat shield and cut holes so that I could re-secure the compressor bracket. I think I measured mine to be 17" x 22" overall before bending/clearancing.

I did cut a hole out of the heat shield for the flex tubing, and I drilled a hole for the dipstick tube to fit through as well. A few times I cut too much off and had to rivet some extension pieces back on to get it how I'd like it.

In the end, using a ScanGauge II, I've watched as the IAT BEFORE was essentially ambient temperature, and now I get as high was 154*F on the highway at 60mph, and I've hit 181*F in city driving. 180*F seems optimal, and I don't plan to pass that temperature.

Please note- I take no responsibility if you choose to do this and it:

A) Doesn't work

B) Messes your car up

C) You get made fun of

D) You hurt yourself in the process

ALSO: Please watch the clearance near the coil packs and/or spark plug wire. I also zip-tied the lower compressor line to the fan assembly to keep it off the hot flex tube.... I also added some electrical tape to my band clamp at the coupler to keep the radiator hose from rubbing it and tearing.

BEEF · 07-11-2008, 12:35 PM

I can't tell by the pics but did you seal the box where the new tube comes in? I used foil tape to seal around where the tube entered the box so I don't lose heat around there and suck in cool air that will dilute the warm air from the header.

your pics look similar to mine. now time for the grill block. maybe even a belly pan if you are feeling frisky.

Project84 · 07-11-2008, 08:02 PM

I used silicone sealant around the pvc elbow, but I'm thinking of cutting a few access holes in the airbox just to let in more air when under high throttle. I felt the car stumble a bit today under higher throttle and I'm wondering if it's wanting more air.

Other option would be to go to a 2" or full 3" HAI raher than have the 1 1/2" coupler.

BEEF · 07-13-2008, 07:16 PM

another option is flexible exhaust pipe. mine is 2 1/8" diameter and does fine. it doesn't have much give to it as my pics show but the flow seems to be fine. also I picked it up at O'reileys for about 5 bucks and I know all of the others have it too (autozone, advance, napa). just check where the exhaust stuff is. it will be in a box and is about a foot and a half long.

just an idea.

SolidLiquidSnake · 07-21-2008, 12:55 PM

Awesome, by the looks of it, fairly easy to do. Something that I've been trying to talk my dad into helping me with. Thanks for this, my dad is going to look at it and think "I know how to do it, but I still don't understand why warm air?"

More debating, I'm sure...

BEEF · 07-21-2008, 01:17 PM

the simple explination is that warmer air doesn't have as much oxygen (by volume) which causes it to use less fuel.

obviously there are a lot of factors that play into this but the theory is just that. less oxygen = less gas.

it doesn't work for everyone. It depends on the car. I know people that have done it on saturns with great success. project84's car is a saturn. and mine is a cousine of the saturn as well.

you may also want to check out a grill block and maybe inflating tire pressure a bit.

Project84 · 07-21-2008, 05:47 PM

Grill block is next on my list, and if that doesn't make me happy enough, I'm going to do a belly pan too!

I've been thinking about ways to do front wheel skirts as well, radius them to be about 1/2" gap between the fender and skirt and mount the skirt rigidly on the spindle w/ 2 nicely tapped screws. I think it would work. The downside to trial/error is the error will probably result in a horrible disaster of shredded fender/tire/brake line/axle boot........ all of which sound not worth it!

BEEF · 07-22-2008, 07:20 AM

I don't know if you have rear fender skirts but I would start there. also (depending on the belly pan) you could extend your front airdam. obviously that doesn't need to be done if you have a belly pan. be careful though. if you have an almost full grill block and a belly pan, not too much air can come into the engine compartment.

I have decided not to go with the whole belly pan because I am worried about cooling. some will say that I am wrong on that one but they aren't driving my car and they don't have to deal with it when it breaks.

remember also, depending on your design for the front fender skirts, you may be adding frontal area to your car which hurts aerodynamic drag.

Project84 · 07-22-2008, 07:15 PM

I'm just lost as to what material to use to keep cost as low as possible.... my whole intent is to mod the car for better FE, but at only driving 9k miles per year, I really need to keep costs down on mods to make my money back in mileage....

That being said, there are some mods I just need to really consider/reconsider because of the cost involved and how long it will take to overcome the cost in my savings... also add into the equation that I'd jump on a nice SC1 5sp car in a heartbeat and sell this car first chance I got.

LarryClapp · 09-30-2008, 08:28 PM

Quote:

Originally Posted by BEEF

the simple explination is that warmer air doesn't have as much oxygen (by volume) which causes it to use less fuel.
obviously there are a lot of factors that play into this but the theory is just that. less oxygen = less gas.
it doesn't work for everyone. It depends on the car. I know people that have done it on saturns with great success. project84's car is a saturn. and mine is a cousine of the saturn as well.
you may also want to check out a grill block and maybe inflating tire pressure a bit.

True, but also less power! Did this on my Honda and hardly got over the mountains in the Smokeys to get home. It idled fine but absolutely no power above idle! I think sensor went beyond its range.

itjstagame · 10-03-2008, 02:20 PM

Then you need a vacuum controlled flapper to switch off hot air and switch on cool air based on load.

I realized this on my truck, felt the lack of air/stumbling and so I put extra holes as mentioned above. Seems to work good, I have enough hot air for idle and get a lot cooler air at WOT.

BEEF · 10-03-2008, 02:29 PM

just remember also that this works best on vehicles that are slightly overpowered. my vehicle weighs very little (relatively speaking) and has 115hp. my metro has about half the horsepower as my current car and of course weighed less. I figure I can get away with about 80-90 hp and be fine.

someone that is already having power issues may want to rethink doing this to their car because of the problems stated above about power loss. It worked fine for me. I can't beat anyone from a stoplight anymore (not like I really could before) but that is fine with me.

guest001 · 11-08-2008, 08:00 AM

hot air = less dense air and less power. less air ie clogged air filter, equals more throttle to compensate for the restriction.

HAI seems pointless to me.

**theholycow** · 11-08-2008, 12:38 PM

Why would it be pointless? You just described one of the major points -- wider throttle. Unlike a clogged air filter, there is no restriction before the throttle, and being able to open the throttle more means less restriction there too. That's less pumping loss, which is a good thing.

diamondlarry · 11-08-2008, 12:59 PM

Quote:

Originally Posted by theholycow

Why would it be pointless? You just described one of the major points -- wider throttle. Unlike a clogged air filter, there is no restriction before the throttle, and being able to open the throttle more means less restriction there too. That's less pumping loss, which is a good thing.

I agree. As long as you keep the rpm's down, a wider throttle opening is better.

Project84, I would suggest that you consider an SL2 manual but swap in the 5th gear set from a '98 or later SL1 manual. This ends up lowering the cruising rpm to the same level as the SL1 as the final drive ratios are the same for both vehicles.

guest001 · 11-08-2008, 02:36 PM

Quote:

Originally Posted by theholycow

Why would it be pointless? You just described one of the major points -- wider throttle. Unlike a clogged air filter, there is no restriction before the throttle, and being able to open the throttle more means less restriction there too. That's less pumping loss, which is a good thing.

It's pointless cause your doing something that's making the motor less efficient. Its the equivalent of not changing your oil, or having 2 or 3+ year oil spark plugs, fuel filter, etc.

if you add a hot air intake the engine has to rotate faster in get more air. which equals less mileage.....

**theholycow** · 11-08-2008, 03:26 PM

Quote:

Originally Posted by guest001

if you add a hot air intake the engine has to rotate faster in get more air. which equals less mileage.....

No, actually, that's the exact opposite of how it works. Instead, it rotates at the same speed, and you have to open the throttle more to get more air.

A closed throttle causes what's called "pumping loss", where the engine has to waste energy just trying to pull air past that closed throttle. Just imagine the muscle exertion required to inhale or blow the same amount of air through a coffee stirrer vs. a jumbo straw. The lack of a throttle to close is one of the reasons (but certainly not the only one) why diesels are more efficient.

See also:
http://www.google.com/search?q=%22pu...+throttle+bsfc

guest001 · 11-08-2008, 07:47 PM

hmmm, ok this is interesting. I'm going to do some more research before I say anything else.

ok, so what are typical gains from this?? I have turbo on my car so my iat's are higher then cars without a turbo anyway.

**theholycow** · 11-08-2008, 07:55 PM

I'm not sure what the typical gain is, but it's significant. However, it doesn't work for every car. I haven't studied the success/failure reports enough to predict which vehicles it works for.

A turbo might change how the WAI/HAI works, since they both work with air density (and the WAI/HAI may also work with some other concepts, like recycling heat back into the engine).

BEEF · 11-08-2008, 10:13 PM

everyone that I have talked to are seeing 5-10 percent increase. there are the few that see none at all. it works really well on the cavaliers and the saturns. I can't really say for other models. I averaged two tanks to see what the gains were and got around 8 percent. I then went on to other mods but the two tanks were over about 900 miles which I feel substantiates the claim (at least in my eyes)

research is the key and also reversability. if anyone is skeptical of the WAI, I say to try it (in a reversable way). if it works, make it permanent. if it doesn't, take it off.

many of my modifications started as prototypes that could easily be removed and were replaced with permanent and relatively eye pleasing additions to my vehicle.