Following the sale thread of a TRD intake elbow, decided to actually dó what I had thought of doing several times: Take the intake duct from the wheel well and give the plastic horn a proper bell shape entry.
It is a faff but for free and worth it imo. The car feels more responsive. Lighter too; no less than a whopping 750 gramms.
So, how to get the duct out:
First jack up that corner of the car enough to give you working space. Best leave the wheel on.
Now get the battery out and set the fuse box to the side (to get at the two plastic screws later on).
Next take the rear light unit out. Two screws at the top and a locating pin, left lower corner. Be carefull as it cán break off.
No need to unplug. Just put it on a rag on top of the air box.
Right. Now comes the faffing.
The plastic is mostly held in place by push fit plugs. They are old, hard and brittle. Look inside and you will see them. Don´t miss the one high up in the middle.
No need to unclip the ones under the sill.
Then unscrew the two bolts under the rear bumper.
Take the bolt holding the bumper skirt to the wheel arch out last.
Lower the plastic on the tyre.
The duct is secured by:
- a plastic screw through a rubber grommet on the rear bumper beam
- two hangers bolted high into the mud guad. Easy to feel and unscrew.
- two plastic screws behind the fuse box. It is a waste of time to try unscrew them as the threaded plastic plug in the metal panel turns round; just behead them with cutting pliers.
Take the duct out form the wheel well.
The plastic air horn is held in place with a plastic screw in a rubber grommet under the collant expansion tank.
Take the srew out and thus the elbow.
With a hacksaw, dremel or a sharp handkerchief cut off the 1 cm. lip from the horn to make it a proper bell shape.
Fit the modded air horn.
Fit the plastic skirt etc.
ENJOY!!!
(https://myalbum.com/photo/JreYhZELzKnr/1k0.jpg)
(https://myalbum.com/photo/Bdb2CNjJnyp8/1k0.jpg)
(https://myalbum.com/photo/hHP8Rxgpjmwm/1k0.jpg)
(https://myalbum.com/photo/BmSKSoaYEzaK/1k0.jpg)
note to moderators: please move if deemed fit
Before moving to How To...
What are the benefits to removing the cold air flow from the side vent?
Are you not just increasing the intake temperature by sucking in more air from nearer to the exhaust? Whereas the air sucked in via the horn and the pipe comes straight from behind the battery.
Surely this is worse than stock as your now not getting the cooler air feed from side vent ?
Above reads that you just removing the pipe that feeds air from side vent down to behind coolant bottle and then cutting the end of airbox feedpipe to make it open trumpet and sucking hot air ? or have i misunderstood something ?
Worth noting that the intake tube within the top of the stock airbox is already a velocity stack - you can cut up the top of the box and fit a cone filter over it which can then be fitted behind the battery using a 45 degree 70mm coupler :)
Remember that the side intake feeds into the rear quarter panel first and thén into the engine compartment.
The rear panel ís the rear wheel well.
The left rear corner is literally shielded from the engine room/exhaust.
In effect it is a relatively still, cool air pocket fed from the side intake.
With the duct fitted the air just sits there. With the horn sucking from it, the air flows in from the side entry.
If anything the air is cóóler as it comes directly from the side vent: The air from behind the fuse box is turbulent from the engine compartment, índirectly from the side vent.
In other words the duct sucks from the side vent indirectly, the decucted horn directly.
TRD did came up with basically the same with good reason. They were well aware that the duct only serves as a inlet noise damper.
Again; it is the same as the TRD mod but retaining the lower end air speed ´boost´.
Quote from: m1tch on July 17, 2019, 12:05Worth noting that the intake tube within the top of the stock airbox is already a velocity stack - you can cut up the top of the box and fit a cone filter over it which can then be fitted behind the battery using a 45 degree 70mm coupler :)
Yes, you could, but why?
It does not get you any cooler air, worse air filtering, adds weight and costs money plus more effort. You still ´need´to take the air duct out as it makes no sense leaving redundant duct.
Again; same as the TRD mod. but for free, retaining the OEM horn.
Fair poibt. It is just a tiny hole behind the battery that the air goes into, so opening it up to the whole side panel hsould indeed offer some benefit. Wonder why they did it that way then? Noise suppression I guess
Quote from: shnazzle on July 17, 2019, 12:51Fair poibt. It is just a tiny hole behind the battery that the air goes into, so opening it up to the whole side panel hsould indeed offer some benefit. Wonder why they did it that way then? Noise suppression I guess
Yes to all.
Engineers are bound in their design brief by the hard limits of the regulations. The heat sink cat is a glaringly obvious case in point.
Quote from: Petrus on July 17, 2019, 12:15Quote from: m1tch on July 17, 2019, 12:05Worth noting that the intake tube within the top of the stock airbox is already a velocity stack - you can cut up the top of the box and fit a cone filter over it which can then be fitted behind the battery using a 45 degree 70mm coupler :)
Yes, you could, but why?
It does not get you any cooler air, worse air filtering, adds weight and costs money plus more effort. You still ´need´to take the air duct out as it makes no sense leaving redundant duct.
Again; same as the TRD mod. but for free, retaining the OEM horn.
The battery provides a heat shield from the engine heat and the airflow comes in from the side vent directly at the cone filter, intake temps drop to a couple of degrees above ambient once moving. I will be taking out the duct soon as well, don't think it weighs a huge amount - saved a huge amount more weight not running the stock airbox and heavy intake hose vs a silicone coupler and lightweight cone - around 2.3kg.
Quote from: m1tch on July 18, 2019, 07:57The battery provides a heat shield from the engine heat and the airflow comes in from the side vent directly at the cone filter,
well, not really directly, but
Quoteintake temps drop to a couple of degrees above ambient once moving.
more directly than through the hole around the corner.
[quot] I will be taking out the duct soon as well, don't think it weighs a huge amount [/quote]
750 grams.
Quote- saved a huge amount more weight not running the stock airbox and heavy intake hose vs a silicone coupler and lightweight cone - around 2.3kg.
Yes, I get that.
I will be removing mine soon I think, there was a K&N kit fitted on mine when I purchased it but I chopped the OEM hosing and positioned it by the side vent behind battery
I guess the OEM setup works well at supplying cold air directly from the side and dampens sound really well but you will still get heat soak from everything around the hosing. Having a filter positioned like mine has probably results in less direct cold air flow but less heat soak, so is there really any difference ?
Quote from: frank130111 on July 18, 2019, 10:18but you will still get heat soak from everything around the hosing.
Well, I don´t agree.
The filter box is shielded nicely and the duct sucking from behind the fuse box the air is as cool as that taken in by any filter behind the battery.
Heat soak does occur crawling along in thick traffic along the coast under the baking southern sun but so would ´yours´ and under those circumstances it hardly matters does it?!
As soon as you get the wheels rolling the temp drops. Even thrashing it up the B-roads on the southern slopes.
Anyway, the deduct with horn mod is effective, easy to do and free :-)
Thanks for the 'how to' Petrus very handy. The TRD intake arrived today, so will fit ASAP.
Quote from: Amarlborough on July 18, 2019, 15:24Thanks for the 'how to' Petrus very handy. The TRD intake arrived today, so will fit ASAP.
Looking forward to your experience with it.
Ánd to photos of it fitted ;-)
I have done extensive temperature monitoring of various intake designs to reach some solid conclusions.
The degrees are in fahrenheit so please do the conversion.
1. Stock intake- very well designed. It will be at least 10-15 degrees above ambient as piping is heated by the rear exhaust. When coming to a stop it will resist heat soak for a good while and the temperature creeps slowly until it will be at least 30 degrees above ambient. When moving again it takes a while for the intake temps to come down from the heat soak of the tubing.
2. AEM style intake- This intake runs to back of the car near the exhaust. This is the worst design and its temps are at least 40 degrees above ambient while driving and it can creep up quickly to 60 degrees above ambient.
3. Short ram tube behind the battery to the side vent - This intake is only about 5 degrees above ambient while driving. Its characteristic is creeping up fast at a stop light to the tune of 15-20 degrees above ambient but once moving it quickly drops rapidly in just a matter of less than a minute to near ambient once more. Its heat source is not the exhaust at all, it is actually the coolant hoses in the area radiating heat.
3A. Short ram with shielding. This intake makes the car run at ambient temperature. The problem with this intake is not enough surface area space so it creates a restriction of the filter. The filter needs enough room to breath especially at higher rpms and the shield is a bottle neck.
3B. Short ram without battery. The battery does act like a shied. Without the battery blocking off hot air it will creep towards the intake and increase temps another 10 degrees.
Advantage with short ram is;
1. less weight
2. Simple design
3. Near ambient temps
4. The least amount of restriction
5. The best sounding. It complements the sound of the exhaust.
In regard to the intake design all of this is trivial as you are not going to get any kind of appreciable power difference. This has been proven on a dyno by a member from long ago who couldn't understand why.
The why is very simple and that is whatever theoretical advantage an aftermarket intake should have is offset by the simple fact that the volume of air entering the intake is miscalculated because the tube is not calibrated to the MAF. Therefore the MAF will underreport and the 02 sensors will see it as the car is running lean so the ECU will add fuel to compensate. When this happens the ECU will not do its magic and increase or decrease ignition timing when appropriate because it has to guess and therefore you will lose part throttle responce.
If you were able to have a intake tube that has the correct calibration vanes it will keep the ECU happy and will be able to calculate the proper amount of ignition timing and fuel.
Thank you Dev!
What about the motivation for the deduct; the Markiii and TRD?
I have read several observations about the first and was keen not to loose lower end tractability.
Have not found much about the TRD but reasoned that they would be unlikely to screw the intake up, minimise customer agravation.
Mý reasoning was following closely your last observation and by maintaining the standard horn hoped to stay close to the calibration ánd copy TRD.
- no expectations of ány power gain; hence my joke about 3/4 of a hp gained. Also I placed it under ´General´, not ´Performance´ ;D
- hope of small small temp improvement
- shed 3/4 of a kilo 8)
Lastly; I líke the bell shaped TRD intake O:-)
Btw. I was aware of 3b. and as I have a smaller battery thought the direct option would be a good idea.
There múst have been several members on Spyderchat going this route as it is such an obvious/easy/cheap one, but I have not found any mention of it.
Quote from: Petrus on July 18, 2019, 11:18Quote from: frank130111 on July 18, 2019, 10:18but you will still get heat soak from everything around the hosing.
Well, I don´t agree.
The filter box is shielded nicely and the duct sucking from behind the fuse box the air is as cool as that taken in by any filter behind the battery.
Heat soak does occur crawling along in thick traffic along the coast under the baking southern sun but so would ´yours´ and under those circumstances it hardly matters does it?!
As soon as you get the wheels rolling the temp drops. Even thrashing it up the B-roads on the southern slopes.
Anyway, the deduct with horn mod is effective, easy to do and free :-)
That is kind of what I was saying, you will always get some sort of heat soak and the difference between the two examples I gave is probably not noticeable at all. Hot coolant runs through the throttle body housing with the OEM setup which will spread heat up the pipe, there will always be heatsoak to some degree.
Quote from: Dev on July 18, 2019, 16:052. AEM style intake- This intake runs to back of the car near the exhaust. This is the worst design and its temps are at least 40 degrees above ambient while driving and it can creep up quickly to 60 degrees above ambient.
@Dev I think they changed the disposition of the air filter on the AEM as it now sits behind the passenger wheel. Was it already the case with the AEM you used for your tests?
Good morning Frank!
Quote from: frank130111 on July 19, 2019, 08:28Hot coolant
Reads really weird doesn´t it ;-)
You hit the nail on the head. The ´cooled´ throtle body is a great equaliser. It actually keeps the heat soak in traffic on hhhhót tarmac dówn.
Once on the go with a healthy amount of throttle opening, the quantity of air rushing through the air artery will both regulated the temp ánd not be heated up all that miuch provided it is taken from an ambient temp. source.
Yesterday the ambient temp. was 38 degrees over here.
Tarmac near 70 degrees.
The cooling system of our MRs is só good that even in slow moving trafic the radiator fan did not cut in.
While moving slowly, nor needing power, the egine does not generate a lot of energy thus heat, meaning the exhaust/cat does not get all that hot either, despite 70 degree C. tarmac!
All in all our MRs are very sound temperature wise.
Yes the exhaust/cat getapear to get very hot but in reality no hotter than on other cars. It is just that on the rest they hang underneath unnoticed.
The crux it that ours need móvement to keep air flowing, taking that heat out from the back, not heating up the engine room.
That observed; remember that ours takes in the air from the side vent; probably cooler than other cars.
Back to the subject; it´s for free!!!! How many ´cool´ mods are?!
Quote from: Gatouzze on July 19, 2019, 09:38@Dev I think they changed the disposition of the air filter on the AEM as it now sits behind the passenger wheel. Was it already the case with the AEM you used for your tests?
Ufff, the passenger side... which side is that in your world?
In all markets the engine room layout is the same, RHD/LHD not.
Quote from: Petrus on July 19, 2019, 09:56Quote from: Gatouzze on July 19, 2019, 09:38@Dev I think they changed the disposition of the air filter on the AEM as it now sits behind the passenger wheel. Was it already the case with the AEM you used for your tests?
Ufff, the passenger side... which side is that in your world?
In all markets the engine room layout is the same, RHD/LHD not.
I meant the left side of the car (when checked from behind) which would be the driver side for non UK drivers.
Thank for pointing this so nicely!
Quote from: Gatouzze on July 19, 2019, 10:16Thank for pointing this so nicely!
No problem at all :-)
The LHS rear is where the OEM intake routes and as such is quite well heat shielded.
On my car I have rerouted the exhaust exit to the other side. A happy coincidence that should aid sómething too.
So the backdrop for the deduct is that I have a smaller battery = less well shielded OEM intake ánd the exhaust exit to the RHS.
Next is a decat pipe and make some more noise, oops, I mean less heat :-) No engineering design team would fit a cat if they did not háve to.
Quote from: Petrus on July 19, 2019, 10:46The LHS rear is where the OEM intake routes and as such is quite well heat shielded.
On my car I have rerouted the exhaust exit to the other side. A happy coincidence that should aid sómething too.
That's why I was wondering about the AEM as the filter goes all the way down in the bumper where the air should be fresher than close to the coolant reservoir.
Just wanted to check with
@Dev if he tried with this one or the one with the filter next to the coolant reservoir (also called a cold air intake).
The coolant reservoir is only an expansion vat. Secondly the horn is not heated by it really. Certainly the air taken in isn´t as that comes from the side vent.
As Dev explains, the OEM intake system is simply very good and furthermore the carburation is dictated by the MAF calibration.
This sets quite limiting boundaries to intake mods: It is not easy to better it and secondly the ECU can only adapt within a very limited band width.
So; marginal gains only ;-)
btw. my ECU does NÓT like the mod.
Or the idle valve needs cleaning because it does not do what the ECU now wants it to do.
Best first some fluid squirt cleaner.
Wait fingers crossed.
Second squirt (lóve that).
Start and drive.
Well, first try fínd the squirt carb cleaner...
Agreed that the cars are cooled really well, never had any cooling issues in any of the MR2s that I have owned. If anything the cooling system is more effective than that of a car with the engine in the front.
Disagree with what you are saying about the coolant around the throttle body, it is pretty well documented that the coolant hoses that run through the throttle body are to prevent the butterfly freezing in place in locations that have a much colder climate. There is a lot of information out there to prove bypassing that system can reduce intake temperatures. I have tested this myself on other vehicles and you do see a slight drop but nothing major. Certainly don't think you would notice much of a difference on a 140bhp engine.
At the end of the day I am not too worried about any of this with a standard 1zzfe, if it had a turbo I would want to bring the temps down as much as possible and if I had a 2zzge it probably wouldn't matter so much either but would be more inclined to try and bring them down.
Having had a previous topic with regards to the coolant hoses into the Idle air control valve (not throttle body), they are there to heat the IACV to prevent cold weather seizing. The coolant never gets near the throttle body opening.
All I can contribute in a that when we had the SP240 turbo kit, the intake was behind the passenger rear light (coolant reservoir side) and the intake temps were absolutely massive at times.
I don't know why. You'd think it'd be reasonably cool there.
Temperature wise I haven't found anything yet that beats the Hurricane setup. Behind battery, enclosed filter, fed straight from the side air vent.
Yes it jumps up in traffic quickly, but not massively. Not like when I had the open cone back there
Quote from: frank130111 on July 19, 2019, 15:36There is a lot of information out there to prove bypassing that system can reduce intake temperatures. I have tested this myself on other vehicles and you do see a slight drop but nothing major. Certainly don't think you would notice much of a difference on a 140bhp engine.
As a side effect, tt keeps it more constant. That is a larger advantage than a slight drop in temp under some cicumstances; we are indeed dealing with a relatively tame engine only.
As Dev explained it is all pretty marginal with the OEM MAF/CPU.
In mý case the battery is a reduced heat shield ánd I have the exhaust exit at the opposed side.
As a bonus I réally dig the retro aspect of the bell mouth, tapered intake horn. Is só in line with the other retro theme things of mine.
Quote from: Petrus on July 20, 2019, 01:21Quote from: frank130111 on July 19, 2019, 15:36There is a lot of information out there to prove bypassing that system can reduce intake temperatures. I have tested this myself on other vehicles and you do see a slight drop but nothing major. Certainly don't think you would notice much of a difference on a 140bhp engine.
As a side effect, tt keeps it more constant. That is a larger advantage than a slight drop in temp under some cicumstances; we are indeed dealing with a relatively tame engine only.
As Dev explained it is all pretty marginal with the OEM MAF/CPU.
In mý case the battery is a reduced heat shield ánd I have the exhaust exit at the opposed side.
As a bonus I réally dig the retro aspect of the bell mouth, tapered intake horn. Is só in line with the other retro theme things of mine.
Sounds like you have put a lot of thought and hard work into it, have you got any pictures would be cool to see?
Quote from: frank130111 on July 20, 2019, 09:38Sounds like you have put a lot of thought and hard work into it, have you got any pictures would be cool to see?
(https://myalbum.com/photo/jMUv9C9Ow06p/1k0.jpg)
(https://myalbum.com/photo/PZif22oPMtJG/1k0.jpg)
(https://myalbum.com/photo/hHP8Rxgpjmwm/1k0.jpg)
Quote from: Gatouzze on July 19, 2019, 09:38Quote from: Dev on July 18, 2019, 16:052. AEM style intake- This intake runs to back of the car near the exhaust. This is the worst design and its temps are at least 40 degrees above ambient while driving and it can creep up quickly to 60 degrees above ambient.
@Dev I think they changed the disposition of the air filter on the AEM as it now sits behind the passenger wheel. Was it already the case with the AEM you used for your tests?
The AEM intake that I tested was my own. The filter was located behind the passenger wheel. Another member had I believe the Ingen version that was closer to the exhaust and it was just as bad.
K&N made one that ran closest to the exhaust and it came with a hose that you had to rout from the side intake vent to shower the filter. It was the dumbest design and yielded not benefit.
The three of us logged temps and they reported their findings to me.
Later on after getting my 2ZZ swap I tested various short ram designs and went though various design changes including shielding to try to get ambient temps but in the end the difference between ambient and 20 degrees above ambient does not make any more power but surprisingly if you drive in cooler temps you can feel a power difference regardless of what intake you choose.
You can actually have some power gain even when running a stock ECU but the changes you make needs to be global.
Just adding an intake is not going to give you more power because that is not the bottle neck unless your filter is clogged. In order to take advantage of reducing any intake restriction you need to start with a free flowing exhaust.
You can get a solid 10hp at the wheel with a downpipe and that is where the bottle neck is. After that then the intake will work synergistically with the entire system. You also have to keep in mind that you need the proper intake that has the vanes to calculate the exact volume of air so that the car can add fuel and timing.
Sadly that kind of aftermarket intake does not exist. If I could build one I would but before anyone has a crazy idea to add adaptable vanes its not going to work and it has been tried before.
What it requires a tube with the vanes strategically positioned and then flow tested with the MAF to read the same voltages that you see with the OEM air box that correlates with the amount of air entering the engine dynamically.
If one wanted to take it to the next level you could even tweak it so you can trick the ECU to make a little more power.
Came up from the coast yesyerday. Over 40 degrees centigrade, tarmac hotter.
Over the pass, took the B-roads. Absolutely flóóred it, revving into the red stripes. Mind, taht is mostly in third, occasionally fourth, not that much air flow.
At the farm, the radiatior fan was on.
Pulled the rear lid open and grabbed the intake horn: Hot but not uncomfortably so; could keep the back of my hand on it.
The down side is that the CPU does not like it; the engine stalls on idle. I like left foot braking anyway, but still gót to find carb squirt and see if the issue is literally solved.
I can hardly ´get´ it; idling great, take off duct, stalls.
That's really odd... And we are talking purely the elbow joint at the front of thr airbox?
I've had that off many times before and it didn't make a single big of difference
I mean, that's before the filter. So it can't be airflow related. Any and all laminar or disturbed flow before the filter will be different after it anyway.
Temperature really is left as the only parameter.
Clean maf and see where you go from there I guess
I agree; not logical, yet; OK, duct off, stalls...
Cleaned maf 10K kms ago but no harm in a repeat when I have the duct off to squirt cleaner in the throttle bdoy/evac.
Methinks your location prohibits you from this mod :)
Have we found a downside to living in a hot place? :)
Quote from: shnazzle on July 21, 2019, 10:21Methinks your location prohibits you from this mod :)
Have we found a downside to living in a hot place? :)
Could be; it is HOT here at the moment.
If you make the mistake if not putting your steering wheel in the shade with a reflective windshield shade, you´re not leaving as it is easily 60 degrees C.
Just took the maf and intake rubber out.
Cleaned the lot and also sprayed stuff on the valve and in the evap hole.
Let it soak while cleaning the duct.
Wiped all off and back together.
The lightest of sealant coating on the maf and presto!
Prompt start and now the idle is a bit too hígh!
Did not take it for a spin so it will need to relearn/settle yet but I wanted to let any muck suck through and not settle dry.
Back to the intake temperature I was not disappointed when feeling the elbow yesterday. It was significantly less hot than the steering wheel of mountain girls´ SUV just now :-)
Down and back to/fro Málaga this evening.
Idle issue solved.
Still; an indication that the deduct/horn mod is a change detected by maf/ecu
Over the pass took the B-road again. Had c-company in the passenger seat so did not push it as much as I would have solo but still spiritedly for the AD08Rs to just start warning.
About 25 degrees C ambient temperature and the cover of the air box was warm, not hot. Would not do the dishes in water that temp.
C-company was relaxed impressed; had enjoyed herself.
Conclusion must be that the deduct was worth it: Worst case it has no effect but for 750 gramm shed and a better intake sound pleasing the girls.