I re-routed the air intake on my 1zz to draw in cooler air.
I wanted to disturb the stock intake (which is well designed, IMHO) as little as possible.
I didn't want to spend much $$ (ended up costing under $10), didn't want to make more noise, didn't want to fiddle with the MAF sensor and didn't want to deal with the little cone filters or oil impregnated filters, which let more dirt in.
And it's a 10 minute job to go back to stock.
Whatever restriction the stock system has is only significant at wide open throttle and high rpm, a condition I basically never reach.
What I want is more mid-range torque, especially on a hot day with the AC cranking.
The stock system ended in front of the battery with some cool air coming in through the gap around the headlight housing.
I removed the end piece, bent the fiber hose down and loosely fitted a length of 3" "dryer vent" aluminum flex hose.
This hose is routed through a gap behind the fog lamp mounting point and ends near the lower grill.
Now the air is taken from a point before the radiator can heat it.
The loose fitting at the fiber hose, plus the end point out of the incoming air stream should reduce any danger of hydrolock.
I decided not to point the inlet facing out the grill for a "ram" effect because it might take in too much water in heavy rain.
Here's an OBD-II chart with the original intake showing coolant temp, speed and intake temp on a 35 minute drive.
This was a cold start, ambient temp 50F, foggy using AC & defroster, mostly stop and go 35mph and below.
Intake stays cool until ~10.5 minutes when I'm waiting in line at the recycling/trash dump.
The radiator gets fully warmed up and the intake rises to 15-20 deg. above ambient and stays there even after I get going again.
With the warm weather on the East Coast I've been unable to do a similar drive with the modified intake.
The above is a warm start, ambient 81F, again mostly stop and go under 35mph.
The intake is heat soaked but cools off to within a few degrees of ambient in ~5 minutes.
With no AC use the radiator fan doesn't kick on until the coolant gets hotter: 205F vs 188F.
The intake stays pretty cool until I get into some bogged down in 10mph traffic at ~54 minutes.
Once I get going the intake starts cooling down. In the meantime the radiator is fully hot & fan is cycling.
By the seat of the pants the throttle response didn't get sluggish in the hot stop-and-go like it has in the past.
Here's 30 minutes of another run. Sorry about the changed order of graphs.
Driving through town then on to the highway.
Warm start, ambient 61F.
The intake falls to within 2 deg. of ambient after a few minutes on the highway.
I wanted to disturb the stock intake (which is well designed, IMHO) as little as possible.
I didn't want to spend much $$ (ended up costing under $10), didn't want to make more noise, didn't want to fiddle with the MAF sensor and didn't want to deal with the little cone filters or oil impregnated filters, which let more dirt in.
And it's a 10 minute job to go back to stock.
Whatever restriction the stock system has is only significant at wide open throttle and high rpm, a condition I basically never reach.
What I want is more mid-range torque, especially on a hot day with the AC cranking.
The stock system ended in front of the battery with some cool air coming in through the gap around the headlight housing.
I removed the end piece, bent the fiber hose down and loosely fitted a length of 3" "dryer vent" aluminum flex hose.
This hose is routed through a gap behind the fog lamp mounting point and ends near the lower grill.
Now the air is taken from a point before the radiator can heat it.
The loose fitting at the fiber hose, plus the end point out of the incoming air stream should reduce any danger of hydrolock.
I decided not to point the inlet facing out the grill for a "ram" effect because it might take in too much water in heavy rain.
Here's an OBD-II chart with the original intake showing coolant temp, speed and intake temp on a 35 minute drive.
This was a cold start, ambient temp 50F, foggy using AC & defroster, mostly stop and go 35mph and below.
Intake stays cool until ~10.5 minutes when I'm waiting in line at the recycling/trash dump.
The radiator gets fully warmed up and the intake rises to 15-20 deg. above ambient and stays there even after I get going again.
With the warm weather on the East Coast I've been unable to do a similar drive with the modified intake.
The above is a warm start, ambient 81F, again mostly stop and go under 35mph.
The intake is heat soaked but cools off to within a few degrees of ambient in ~5 minutes.
With no AC use the radiator fan doesn't kick on until the coolant gets hotter: 205F vs 188F.
The intake stays pretty cool until I get into some bogged down in 10mph traffic at ~54 minutes.
Once I get going the intake starts cooling down. In the meantime the radiator is fully hot & fan is cycling.
By the seat of the pants the throttle response didn't get sluggish in the hot stop-and-go like it has in the past.
Here's 30 minutes of another run. Sorry about the changed order of graphs.
Driving through town then on to the highway.
Warm start, ambient 61F.
The intake falls to within 2 deg. of ambient after a few minutes on the highway.
