IAC restriction plate

[vladj]

well i did it today and i love it. now i can put it in 2nd at 6k RPM really fast with out it grinding. Great mod id reccomand it to anyone:

http://www.elantraxd.com/forums/showthread.php?t=19409&page=2

thanks;

vlad

[Keyan]

whoever thought to restrict the IAC is a god.

the hanging RPMS suck my left nut. especially with my exhaust; trying to push the clutch in when driving past cops, and the rpms just holding there !

[zx2uner]

nevermind, I answered my own question....ha

[04 elantra cvvt]

Vlad, did this totally cure the problem? Also, when you rev the motor in neutral, does the engine return to idle quicker?

[slow 2K2GT]

yes it returns to idle quicker, the only thing you need to watch out for is that the hole is large enough so when you are decellerating your car doesnt buckle and shake.

[04 elantra cvvt]

yes it returns to idle quicker, the only thing you need to watch out for is that the hole is large enough so when you are decellerating your car doesnt buckle and shake.

Cool.. thanks. Did you go larger than 5/16"?

[slow 2K2GT]

I dont know, I used a pop can as a gasket and just punched a wood nail through it...if anything I would say I was smaller.

[xdforme22]

Sorry for my ignorance, but...
Can someone explain how this mod works (as in how the part works normally and how this mod differs the normal operation to fix this problem)? I n am thinking about doing this but don't want to hurt the engine/have engine trouble. Do you think this mod could cause problems in winter (as it would not get up to operating temp as quickly)? Does it kill gas milage?
Thanks for patience with these simple questions.

[slow 2K2GT]

umm I dont see it hurting anything. All this mod does...and you should read through the DIY from the above link first...is restrict the amount of air that the IAC gets...The IAC is the sensor that causes the revs to hang during a shift or when you let off the gas, though I think its mostly in manuals. When you cut down the air flow to the IAC your revs will come down a bit quicker.

No I dont think this will effect fuel mileage either way.


yes it did now i can throw it into gear at 6500 RPM and before if i forced it in the gears would gring but now its just goes in quietly and nicely. oh and in nutral whenu rev it it actually goes down slower and stopps at 1100 RPM for like 20 sec then goes to 800 RPM. And when u drive like in 1st gear with out pressing the gas it actually drives and i went up to the 4th gear without pressing the gas it just kept accelating.

EDIT: i used 5/16" hole exactly

Well there you go.

[vladj]

Vlad, did this totally cure the problem? Also, when you rev the motor in neutral, does the engine return to idle quicker?

yes it did now i can throw it into gear at 6500 RPM and before if i forced it in the gears would gring but now its just goes in quietly and nicely. oh and in nutral whenu rev it it actually goes down slower and stopps at 1100 RPM for like 20 sec then goes to 800 RPM. And when u drive like in 1st gear with out pressing the gas it actually drives and i went up to the 4th gear without pressing the gas it just kept accelating.

EDIT: i used 5/16" hole exactly

[04 elantra cvvt]

Actually slow, the IAC is the Idle Air Control Vavle. It lets air past the throttle body when it's closed. It also opens when you give it some gas so that it doesn't die when you let off of it. It works like a dashpot on a carburetor. This is the part that will cause a fluctuation in idle RPM when it goes bad.

[kylemorg]

I...don't want to hurt the engine/have engine trouble. Do you think this mod could cause problems in winter (as it would not get up to operating temp as quickly)? Does it kill gas milage?

Remember, this mod is completely reversable. You can take the restrictor that you built out as easily as you put it in if you find you have any problems with anything.

[slow 2K2GT]

Actually slow, the IAC is the Idle Air Control Vavle. It lets air past the throttle body when it's closed. It also opens when you give it some gas so that it doesn't die when you let off of it. It works like a dashpot on a carburetor. This is the part that will cause a fluctuation in idle RPM when it goes bad.

Sorry my bad, I realised what I typed after I went to bed and was too lazy to come down and change it.

[silversharkXD2]

If it goes bad...it will keep you from driving your car. you have to leave your foot on the accelorator at all times or it stalls out. This is very hard with a manual...lol. And it cost me 350 to replace on my RD

[mnstrmech]

i just did this today, found an old two layer steel head gasket laying around in teh shop, perfect material! and I LOVE IT! teh car is so much easier to drive. like a "normal" car! those revs hanging annoyed me too!

[Keyan]

installed it. I love this mod !!!


I have alot of aluminum laying around, would anyone be interested in me making them one for a couple bucks??

[slow 2K2GT]

its a great mod isnt it!!! I like mine too, I took the time to do it right this time.

[04 elantra cvvt]

installed it. I love this mod !!!


I have alot of aluminum laying around, would anyone be interested in me making them one for a couple bucks??

PM sent.

[xdforme22]

installed it. I love this mod !!!


I have alot of aluminum laying around, would anyone be interested in me making them one for a couple bucks??

PM sent:D

[KeWLKaT]

installed it. I love this mod !!!


I have alot of aluminum laying around, would anyone be interested in me making them one for a couple bucks??

how much? pm me!

you stole all my redbull! :abovelol: :mad:

[elantra_mn]

Ok, stupid question, is there any advantages of doingthis to an automatic?

[04 elantra cvvt]

Probably not. You don't have the issue of hanging revs like the m/t cars do.

[doorsfan18]

on a non-cvvt 2003 engine how big is the hole you need to drill to let the air go through???? the holes on the gasket on a non-cvvt are much smaller than on a cvvt engine so i figured it needed to be smaller. but how much smaller???

[04 elantra cvvt]

I would start with a 5/16. That way, it still gets the same amount of air as the other IAC.

[only1db]

btw....i looked this up...this actually hurts full throttle response....when you go full throttle the iac actually opens up with the throttle plate...so your letting air in from two sources...with the plate in your not letting in as much air at full throttle....so you are restricing the air flow....

so in other words for something that you can go to the dealership and have a reprogram done to cure what you guys think is a bad thing (which i might add is not)you taking away hp and torque....and not getting full throttle response.

[mnstrmech]

but instead ive found that it makes the car soo much more driveable, i could care less about ful throttle power, my car has never seen full throttle!

[Keyan]

i dunno derek, my WOT seems a bit more peppy with the plate. i guess because the IAC throws air into the manifold at a different angle there is less turbulence now because of the less IAC air?


i dunno. i'll test it at the track on friday.

[only1db]

that and dyno numbers...either way if your getting less air in there...and we are running rich to begin with...your losing power somewhere.

[quickfingerz]

I just did this mod. It's great. Gears sync much quicker, so it's probably easier on synchro's too.

I used a soda can that I cut out to the same outside shape as the gasket. I then used a hole puncher (at the office) to punch 4 very clean holes, 2 for the screws and two for the air. The hole is 5/16" and it works great.

[Munky]

James, you still making these?

[Doohickie]

Ok, stupid question, is there any advantages of doingthis to an automatic?
I have an AT and I may try it. Here is what I think it might do: When I get on the freeway and accelerate to speed and back off the pedal, the car does not immediately upshift, but kind of hangs in the lower gear for a bit longer than I would expect. I noticed this on my initial test drives on both the Elantra and the Spectra5... the engine seems a little too "happy to rev", imo.

I'm thinking that maybe it will result in quicker upshifting when lifting off the gas pedal.

Any ideas from the resident experts regarding my theory?

[mnstrmech]

i did this mod initally with a 1/4" hole, awsome without the air, but when the air is on and you push in the clutch, it kinda wants to die everytime. so i drilled out to 5/16", too big, and it was like i didnt even have a plate, so i remade one back at 1/4" hole.

[BColeman]

Doohickie, my wife's '04 GT Sedan does the same thing. Even adding an Intake, and at one point, a cat-back exhaust, did nothing for it.

I would then have to assume that this may help those revs drop a little faster, thereby making the upshift happen a little quicker. The term "slushbox" can be so fitting to the XD/XD2's auto-tranny.

[Keyan]

I've noticed an extreme loss of gas milage since I've installed the plate. I dont know if I can blame that on the plate though (I'm talking about going 3/4ths of a tank and only going 200 miles).

I think my o2 sensors might be gonig bad since i've been getting a lot more "popping" in my exhaust but I want to investigate this further before calling the retriction plate a "perfect mod for everyone"

[BColeman]

Keyan, the same thing has happened to me, except I didn't install the IAC. It started right after I installed the TB pulley, like the one you've got. I've noticed 2mpg drop. Most of that I think is just getting used to the instant throttle response, and how far to push the pedal when driving. But it could be the IAC plate too.

[Doohickie]

hmmmm..... Makes me think twice!

[slow 2K2GT]

hmmmm..... Makes me think twice!

Im so gonna do this, my turbo isnt burning enough fuel as it is, must burn more fuel!!!:D

[vladj]

my milage actually went up with this plate

[quickfingerz]

Mileage would be moot point. We're talking about the air that passes through the IAC . So we have 1)idle & 2)when you let go of the accelerator. When you push the accel the IAC closes so gas mileage isn't going to change very much.

Another note:
When I'm in gear and I let off the accelerator you actually feel some "engine braking".

If you've driven a stick with other cars, it just makes it more like them.

[only1db]

quick...you are wrong...the iac is at full open when you are in it...so by restricting it you are hurting performance....the butt dyno can be decieving.

[06elantra]

i may have to look at doing this mod - seeing as the hyundai dealership has given up trying to locate whats making my car flare/hang/hunt.

il have a play around with it on the weekend and see what i come up with - but, will this ruin my warrenty claiming ability for this problem?
im thinking it will, as i have now pulled the car apart as such and put my own pieces in there...

[04 elantra cvvt]

i may have to look at doing this mod - seeing as the hyundai dealership has given up trying to locate whats making my car flare/hang/hunt.

il have a play around with it on the weekend and see what i come up with - but, will this ruin my warrenty claiming ability for this problem?
im thinking it will, as i have now pulled the car apart as such and put my own pieces in there...

If it doesn't fix the problem, I would bet that the dealer would not have nice things to say if they found the plate in there. But, if it does fix it, then it's fixed, right?