Does a 5th gen Prelude have secondary VTEC. As far as I understand the secondaries in other VTEC engines, are butterflys that open up in the intake manifold and allow more air into the engine. Well does the 5th gen have this also.
Wondering because my bro just did a complete Comptech Sport I/H/E modifiction on his 01 GSR and I could really notice when the secondaries kicked in at about 5600 RPM. I don't really near the that sound in my 5th gen. BTW the only engine mods I have are AEM CAI and a Mugen catback.

 

the h22a1 and 4 have the secondary butterflies in the intake manifold that open up after 4900 rpm

 

GSR, H23, H22 have them.. maybe others too.

 

Ok so the H22A series engines have them, is there any way in which one could determine if the secondaries are kicking in. For some reason I feel that mine are not kicking in, also wondering if my CAI install over a year ago my have affected the operation of secondaries.

Edit: I've never had the check engine light come on after the install of any of my mods.


[Modified by RY8127, 2:21 PM 10/13/2002]

 

well, if you have a CAI, then you already removed one set of butterly valves that were in the resonator.....that's probably why you don't feel anything

 

Yeah you're right I did remove a lot of vacuum lines when I installed my CAI. What I'm wondering is if those vacuum lines some how controlled the intake manifold's secondaary butterflies. here's some pics of what I'm talking about.
These are the lines that I removed from the resonator, I also romoved the Intake Control Diaphragm (the circle thing on the box) and the Vacuum Tank (the box shaped thing that has the tubes going to it.

Here's a diagram (the circle indicates where I think the problem lies in controlling the secondary butterflies.)

Here's a closer view of the Vacuum Tank, Intake Control Diaphragm, and the Intake Control Solenoid Valve.

And here's a pic of how my intake manifold looks.

The middle one is capped stock, but the other, I put the cap on, and this one would normally have a vacuum hose connecting to it from the resonator.
If I can provide more clearity let me know.


[Modified by RY8127, 4:30 PM 10/13/2002]

 

# 14, is the secondary butterfly.# 17 is the vacuum diaphram that open and closes the butterfly.


#12 is the vacuum tank, that controls the Vacumm diaphram.Which is located under the intake manifold.The vacuum line that goes to the tank is located on the back right side of the manifold.


All the parts in your pic's have nothing to do with the operation of the Secondary butterfly.



[Modified by Cottonwoodz, 5:51 PM 10/13/2002]

 

Thanks man that helps a lot is that a 4th gen diagram or a 5th gen. I'm gonna go check my car now.
Hey Cottonwoodz where's that second diagram located in the helms.


[Modified by RY8127, 5:02 PM 10/13/2002]

 

Thats for a 4th gen.
Did you need one for a 5th gen?
I think they are the same setup


[Modified by Cottonwoodz, 5:58 PM 10/13/2002]

 

Well I check the Intake Manifold again and I was able to find the controller for the butterflies, its the round gold thing in the pic and the red outlines the vacuum hose going to it. However I couldn't determine where it leds to. But I checked in my Helms and was able to somewhat determine that the secondary butterflies have nothing to do with what I was concerned about earlier in the thread. I am going to dig deeper and determine for sure though.


Thanks a lot cottonwoodz you really helped, oh and there is a slight difference in the manifold between and 4th and a 5th.

 

u probably willnt hear it like i do but when they open mine sounds like a weak vtec. if u have vtec, the vtec will probably be louder so u cant hear it....

 

Dude you remove your secondary butterflies. Now there open all the time, so you lose mid and low end torque. The reason they don't make noise like your bro's GSR is because unlike the GSR (which activates Vtec at 4,400 rpm and secondaries at 5,700 rpm) The H22A activates both at the same time.

 

I really don't think I removed anything that concerns the secondary butterflies directly, however and like I said in my last post on the thread I was and still am unsure about the removing of the hoses around the resonator, for some reason I think removing those hoses may have indirectly affected the secondaries.
I'll probably take it to a Honda dealership and have them do a vacuum test on the Intake Air Bypass (IAB) Valve, or a.k.a. secondary butterflies. Then I know for sure.
Oh and this will probably be a test for them as they probably don't get this request often.

Edit: and I'm aware of the fact that my bro's GSR engages VTEC at 4500, and butterflies at 5600.


[Modified by RY8127, 9:41 PM 10/13/2002]

 

hmmmmm... after i installed my CAI i lost a TON of low end power. i ripped out a bunch of **** from the resonator and another small box that was under the stock intake. maybe my secondaries are disabled too? i think i had to plug off two caps on the throttle body, not one..

 

I really think I found something here guys, and I'm gonna go to Honda and have them run that vacuum test on the IAB valve (secondaries), and we'll see.

 

i think your overreacting and everything is working properly...

like they said, you wont be able to hear the secondaries because vtec engagement is within 100 rpms of the secondaries

 

ok, there are two sets of secondaries........one in the resonator area and one right in the intake manifold...just a little misunderstanding

 

Sorry...but the prelude does no activate them at thesame time. Butterflies open at ~4800, vtec is at ~5500. Also A Vtec is b4 the butterflies on a GSR You have the 2 backwards. on a GSR it is almost the same as on a prelude. Think about it...there wouldn't be enough airflow to use vtec if vtec kicked in b4 the butterflies. Also vtec at 4400 on a stock car? no way.
Josh

 

If you removed the IAB (Intake Air Bypass) canister you've taken away the ability for the computer to close the secondarys during startup (or under 4,900RPM). Basically your secondaries are now open fulltime, causing the loss of lowend torque. The IAB canister is simply a chamber which keeps vaccum for the IAB diaphram (gold looking piece bolted to intake manifold), holding them closed. But when 4,900RPM is met, a signal from the ECU is sent to the IAB canister, opening up the hose connection to the intake manifold, causing a loss of vaccum, which opens the secondary butterflies.
The vaccum that the engine produces at high rpm is not enough to close the IAB diaphram, that is why the butterflies do not close themselves (once again) at high RPM.

 

ok that makes sense now that I look at this pic again

On the resonator it looks like theres a diaphragm also there's a vacuum box, and a solinoid. So I guess whenever someone installs a CAI on a prelude they remove a butterfly on the resonator, which has it own independent vacuum mechanisms, which don't directly affect the Intake Air Bypass Valves (intake manifold butterflies)?

 

Correct. The set of butterflies in the resonator simply act as a noise supressor during idle and around-town driving, but then open up at a higher RPM for added flow. I'm not 100% sure of the opening RPM since I havent seen the information in a while, but I believe it is somewhere around 4,900RPM. Either way, YES, they are two completely seperate systems with their own independent opening mechanisms.


[Modified by H22Si, 12:41 PM 10/14/2002]

 

Ok my secondaries work. I just test the IAB Valve, here's what I did.
1.) drove the car to get the temp up to VTEC temp.
2.) had my brother rev the car up to 5300 RPM, as he was doing this I was watching the switch to see if it would move, and guess what it did.So the valve opened at the correct time. see pic below.

So the IAB Valve works properly. Thanks to everyone who helped me out.
------------------------------------------------------------------------------------------------
Ok one more thing.
H22Si you say the valves open up at 4900 rpms which sounds right, (cus in my helms the trouble shooting flow chart wants the mechanic to raise the RPMs to 5000 when check for no vacuum at that engine speed) so that seems accurate.
Now my question concerns Apexi VAFC. VAFC allow you to adjust the VTEC engagement timing through a broad RPM range. Can you also adjust the secondary timing also? Take the hypothetical. I get VAFC and adjust the VTEC engagement timing to 5000 RPM (which I would do and consider to be a safe point) Now the secondaries and the VTEC engagement point are really close to eachother, is that good or bad. Also is it better to allow spacing in between these system two engagement points?
Hmmmmm good question.........
E- to whoever can answer that with facts.


[Modified by RY8127, 12:04 PM 10/14/2002]


[Modified by RY8127, 12:08 PM 10/14/2002]

 

You could have tested this be just checking the position before and after turning the car on. The butterflies are open by default. When you start the car, they will close.

 

That's a simple check, I was more concerned with the engagment of them at VTEC range or approimately VTEC range. Thanks though, and I understand what your talking about.

 

You can also watch it move yourself; I've done this. Start the car, leave it in neutral, pop the hood, reach in and crack the throttle and rev the engine. You don't get to see the tach, but you can watch the diaphram activate.