Michael's8

Dominion,

Thanks for the reply. I'm sort of too far down that road at this point, as I've purchased the MS CAI recently (don't remember what I paid, but it wasn't cheap at all). I was just wondering if I could do this mod along with putting in the CAI.

Michael

DOMINION

Yes you can.

Keef

I actually just did this "mod" today... With the temperature's in Houston being 90 + humid, I feel heat soak as soon as I start the engine. Once I did it I felt stupid for not doing it first though...

I could ~kinda~ feel it, nothing spectacular but the air just "feels" a little cooler than what it used too be. I wanna say most of this is fault too that K&N intake. If I'm not moving, than the RB duct isn't doing anything and my engine gets too breath it's heat.

kersh4w

iTrader: (3)

would this mod being acceptable in maryland? we definitely have our hot days (and i suppose MM did this while still living in md.) but we also have days that can hit 20F in the winter.

Bran

with fall, days away and many temps dropping to record lows so early in the season... I ask at what outside temp should the bypass be changed back to avoid condensation or other problems?Any suggestions or what have some of you others done since doing this mod when temps fall off?

djmano

i couldn't resist any longer. a mod that costs $10 dollars and will alleviate my sluggish throttle response after extended driving, how could i pass that up?!

purchased the 5/16 barb and hose clamps from local ace hardware. got the vacuum caps at pep boys, they didn't have the set of 3 black 5/16 caps so i had to buy the assorted version so i have white 5/16 caps booyah! +50hp for white vacuum caps.

in my infinite wisdom when i was putting the throttle body back on i overtorqued one of the (4) 10mm bolts and the end of the bolt snapped off. so now i have 3 bolts holding the throttle body to intake manifold. should i be worried about this? im really scared about using traditional screw extractor because the diameter of the bolt is not too big already, i only have 1 drill bit thats smaller than the bolt. i took it for a short test drive and everything seemed fine.

ill post again after i do some extended driving....i beat my poor 8 to from OC to LA quite alot so ill see how it fares under those conditions.

Myardor

iTrader: (7)

Guess you did not have any spelling training? At even at COLLAGE? no ACCUALLY training either?

Soravia

I believe the coolant line is there for more than one reason. My 91 Nissan 240SX also has the same setup, sadly it runs longer though the intake manifold, not just the throttle body so it cannot be removed w/o fabbing a custom manifold.

The reason it is there is probably to keep the thottle body within certain temp range while the vehicle is in operation. NOT to warm it up on cold weather starts. With the coolant running though the throttle (which has electrical and plastic parts) it is certain to be within the coolant temp range and NOT too HOT because of the weather or heat from the engine bay. It sure won't keep the throttle body cold but it will also prevent too much heat from being trapped in the throttle body at certain rare conditions.

John Corbitt

It is there to prevent Icing. "Carburetor Icing" can occur at temps as high as 70F. Unlike aircraft, cars are at partial throttle 90% of the time. This is when the greatest chance of icing can occur.

Soravia

There's no Carb in the 91 240SX nor RX-8. With the engine running there's much less chance of the throttle freezing up even in snow fall.

MazdaManiac

iTrader: (3)

"Carburetor Icing" cannot occur in an FI throttlebody.
FI TBs are not designed to create the venturi effect needed to atomize fuel, which is the cause of icing.
It has nothing to do with temperature directly, but the dewpoint and air velocity changes across surfaces cooled by fuel.

John Corbitt

"carburetor Icing" is a term. Fuel injected piston aircraft engines have an "alternate air" intake which takes warm air from the engine compartment to melt ice that forms in the throttle body. it also bypasses the air filter which can ice over in the right conditions.
Venturi Icing can occur in your throttle body if it is not heated. With the butterfly valve mostly closed you have a vacuum on one side. The air traveling from a region of high pressure to a region of low pressure will remove heat energy from the air. This is the principle of your a/c system. (vapor cycle machine) Large aircraft use an air cycle machine which is a glorified turbo. It is not uncommon on a 95F day to have ice rattling in the duct. Jet engines require the intake of the engine to be heated when there is visible moisture and the temp is at 8C or colder. Otherwise icing can occur on that large opening.

p.s. Bernoulli's law P1V1/T1=P2V2/T2

P=Pressure, V=Volume, T=Temperature

MazdaManiac

iTrader: (3)

Very nice. Good homework. Nice formulae.

The TB on the RX-8 will not ice. It doesn't matter what the dew point is.
Try it some time.
The RX-8, as great as it is, is NOT an airplane.

SpIcEz

Thread Revival

I just did this mod.

Without cutting the tubing as Im in Montreal and it gets VERY cold.
I honnestly dont think it will affect anything at all, but just in case I left the full length there in case I want to return to stock.

I honnestly was quite impressed with the results.

Im not claiming any power or anything, but I definatly felt an engine/throttle response difference.

Decided to try out 87 Octane as my tank was almost empty and I had to gas up.
And still felt perfectly nice and smooth with 87 and it was quite hot out today.

All in all, cheap and easy.

p.s. for us canadians, in Montreal anyways, it took me 3 hours to find all the parts needed and 5 Canadian tires + a few home depots.

There is no such thing as a 5/16 male/male barb here. sheesh.
Ended up using 3/8, a bit big, but still fits.

Oh and one more thing, damn Canadian tires dont sell packs of the same vacum caps. They have a 4$ pack with ONE of every size. That meant I had to buy TWO packs at 4$ a pop, stoopid canucks eh ?

Jax_RX8

Side Effect Caused by this Mod

I did this mod the simple way that TeamRX8 suggested, with the screw inserted into the coolant hose and put back on (works great by the way). I did this mod last winter and all has been well, engine seemed more responsive and all.

Here is the problem - on very hot days this summer after driving about 1.5 hours (I have a long commute), I noticed my car kept going into limp mode from detonation issues and I could not figure out why. I kept thinking all the traditional things, but what this wound up being, was this mod - let me explain.

I noticed that in the winter through not too hot months, the Throttle Body (TB) was actually cooler by having the coolant flow stopped. But on very hot days after long drives, the TB was getting extremely hot, even with my hood vent mod in place to keep the underhood temps down. This got me thinking, could it be this mod?

When I removed the screw and allowed the coolant to flow again, on many very hot days that I have driven since restoring the coolant flow, this detonation issue causing engine hesitation has NOT happened again (all the while running the same premium fuel and MMO premix)

What I have surmised, is that on very hot days and long drives, the coolant actually keep the TB cooler than it would be otherwise (although it does the opposite on cooler days), and thus it is heating the air entering the engine too much causing detonation issues.

If you live in a hot climate and/or are having detonation issues in hot weather and have this mod, you may want to reverse this mod to see if it cures the issue.

One last thing, if you use Team's method (it takes 30 second to put in and 30 seconds to remove) instead of permanently moving your hose configuration, this is easy to put in place for most of the year (cooler months) and removing during the hot months.

Hopefully this will helps others that may have come across the same issue.

ASH8

bump

justjim

I just did this mod. I've done it on every car I've owned since the late 80's. I live in a warm climate so I'm not worried about any problems with it. I perused this thread so forgive me if what I'm saying has already been said.

Do this when the engine is cold. Open the radiator cap to make sure there isn't any pressure in the system then put the cap back on. For those who had difficulty with the bottom hose, there is no need to remove the TB. Once the airbox and accordian hose to the TB has been removed and a couple of wires unplugged you can view the lower hose connection to the TB. With a pair of needle nose pliers you can pinch and slide the spring hose clamp off the TB. Then with a large flat blade screw driver place the screwdriver blade vertically against the end of the lower hose where it butts against the TB and gently twist the screwdriver blade and push the hose to the left (viewed from the front) with the blade of the screwdriver till its off the barb. I didn't add any hose. When you disconnect the lower hose from the TB and its loose, you can pull it from behind the alternator. Just grab it on the passenger side behind the alternator and pull it through. Then you have enough slack to connect it with a male/male hose barb to the other hose now off the top of the TB. Run the engine till warm and check for leaks, the new connection is now more readily visible since its out where you can see it. The whole thing took about 30 minutes.

notorque

just did it, very easy.

did a little research, mazda didnt do this for cold starts or engine warm up at all. Almost every manufacturer has to do this for emissions, unless the car is ulev before hand.
warmer air entering into the combustion chamber makes for a more fulfilled flame front propagation.......so at low RPMs this helps maintain emissions. but if your like me and constantly stay above 3g then flame front is no issue. just like high idle at cold start to get the cat to warm up faster.

its all gov crap.

now keep in mind older cars did this for a completely different reason than emissions.

Nemesis8

iTrader: (3)

The best way to do this, is to actually unbolt the throttle body. Makes getting to the lower hose simple.

Nemesis8

iTrader: (3)

I was tracing the coolant lines for this. I can see the feed line coming off the thermostat tree on the passenger side front, but trying to trace the line going back to the block is tough. It looks like it is the line right next to the rear engine lift point on the passenger side also. Is that correct?

I'd like to make just one hose with no bard/clamp fittings to worry about leaking.

Kane

iTrader: (1)

You are right - gonna have to take the UIM off to get a real clean shot at the rear one.

On Nesters 8 - I capped them - didn't seem to cause any problems.

ASH8

Yes, the other By Pass Hose goes on the rear Rotor (iron) Housing on the Passenger side like you said, so really you need a relatively short hose to join the two points.

You could probably use (cut) one of the two original hoses to make a neat fit.

Please let us know.

Ash

Nemesis8

iTrader: (3)

Will do. I might do Kane's method and just cap them off, unless there is a benefit from sending coolant to the rear iron? Might be next weekend though, still have to swap brake pads and fix my clutch bracket in time for my track day coming up. I was thinking it would be bad to blow the coolant lines, where I patched them together with hose clamps, while on the track.

WTBRotary!

iTrader: (6)

Ok so long story short does/ Would this void or have a possiblity of voiding our 8 year, 100K mile Powertrain Warranty??? Because I'm thinking about doing this Mod but I do NOT want to void that warranty. Heck with my Luck ill be needing a new engine in 20,000 miles lol

swoope

iTrader: (5)

you do not have a 8 year 100k power train warranty.. power train on the 05 i think is 5 yr 60k miles.. could be just 4 / 50.

the 8 / 100 is the engine core alone..

as to the mod, i doubt anyone would notice, it is a very stealth mod.

beers