All Time VTEC....
10-23-2003, 04:38 AM
#1
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All Time VTEC....
why doesnt honda have the engine run on vtec constantly? im sure there is a reason but what is it anyone know?
10-23-2003, 04:45 AM
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Re: All Time VTEC.... (shaun311)
sure, you would have an engine that doesn't perform as well.
when you change lobes on your cam for VTEC, it changes the characteristics of the engine, and at a low rpm those lobes are undesireable.
you could do VTEC all the time if you hook up a VTEC controller, set it to come on all the time and then come back and tell us how crappy it was running.
when you change lobes on your cam for VTEC, it changes the characteristics of the engine, and at a low rpm those lobes are undesireable.
you could do VTEC all the time if you hook up a VTEC controller, set it to come on all the time and then come back and tell us how crappy it was running.
10-23-2003, 04:47 AM
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Re: All Time VTEC.... (shaun311)
Running on high cam alll the time would defeat the purpose of having vtec at all. The whole idea behind it is to be able to tune the power to 2 separate sets of cams. If you ran it at high cam all the time it would be like having a race cam in it all the time (and not having any bottom end power to match!!).
It's early, and that's the best I can do right now. If you search for vtec in the tech forum I'm sure you'll find a better explaination.
It's early, and that's the best I can do right now. If you search for vtec in the tech forum I'm sure you'll find a better explaination.
10-23-2003, 05:01 AM
#6
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Re: All Time VTEC.... (shaun311)
even if you set it around 3000rpm's or something it will still hurt your performance. If you change vtec crossover it has to be tested on a dyno to get the best results. On a basically stock setup there is really no need to change the vtec crossover point. It was set there from the factory for a reason.
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10-23-2003, 05:30 AM
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Re: All Time VTEC.... (95excoupeMT)
It's kinda like 3rd gear.
3rd gear is my favorite gear any time after 6000 rpms.
Now imagine being in third gear all the time. Starting off at the line in 3rd gear and staying in it until 90+mph, then shifting. Imagin that, that's probably how VTEC would be if it were on alll the time.
3rd gear is my favorite gear any time after 6000 rpms.
Now imagine being in third gear all the time. Starting off at the line in 3rd gear and staying in it until 90+mph, then shifting. Imagin that, that's probably how VTEC would be if it were on alll the time.
10-23-2003, 06:23 AM
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Re: All Time VTEC.... (2camsaam)
Vtec in USDM cars is activated by Oil pressure. It takes a certain amount rpm to build that oil pressure. SO your car will be so slow a Tercel would murder you off the line.
10-23-2003, 07:34 AM
#10
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Re: All Time VTEC.... (Apex i ITR)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Apex i ITR »</TD></TR><TR><TD CLASS="quote">Vtec in USDM cars is activated by Oil pressure. It takes a certain amount rpm to build that oil pressure. SO your car will be so slow a Tercel would murder you off the line.</TD></TR></TABLE>
Nope...WRONG!
Have you ever had a oil pressure gauge in your car? My D16Y8 make 75+ psi of oil pressure under load and just barely above 2000 rpm. So in that case my VTEC should kick in around 2000 rpm? NOT!
The ECU tells the VTEC switch to let the oil pressure into the valvetrain to turn it on. After that, if there is not enough oil pressure, it turns off the VTEC switch, slamming you back to the base lobe and throw a CEL.
On a dyno, I have manually played with VTEC. Just disconnected the VTEC harness and use a 12 volt probe to touch the VTEC wire. When the car was idling, I activated VTEC and the car sputtered like a V8 engine with a drag cam in it....then died and threw a CEL, most likely since it didn't have enough oil pressure at idle.
Nope...WRONG!
Have you ever had a oil pressure gauge in your car? My D16Y8 make 75+ psi of oil pressure under load and just barely above 2000 rpm. So in that case my VTEC should kick in around 2000 rpm? NOT!
The ECU tells the VTEC switch to let the oil pressure into the valvetrain to turn it on. After that, if there is not enough oil pressure, it turns off the VTEC switch, slamming you back to the base lobe and throw a CEL.
On a dyno, I have manually played with VTEC. Just disconnected the VTEC harness and use a 12 volt probe to touch the VTEC wire. When the car was idling, I activated VTEC and the car sputtered like a V8 engine with a drag cam in it....then died and threw a CEL, most likely since it didn't have enough oil pressure at idle.
10-23-2003, 08:41 AM
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Re: All Time VTEC.... (Marauder)
ivtec is kind of like that cause it doesnt really have a vtec crossover like the older engines. have u heard of the vtec killer cams? well it basically makes it so that you have vtec all the time but it a race setup only. plus you would not necesarily be making more power if you set vtec to a low rpm or if it was on all the time.
10-23-2003, 08:54 AM
#15
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Re: All Time VTEC.... (Marauder)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Marauder »</TD></TR><TR><TD CLASS="quote">
Nope...WRONG!
Have you ever had a oil pressure gauge in your car? My D16Y8 make 75+ psi of oil pressure under load and just barely above 2000 rpm. So in that case my VTEC should kick in around 2000 rpm? NOT!
The ECU tells the VTEC switch to let the oil pressure into the valvetrain to turn it on. After that, if there is not enough oil pressure, it turns off the VTEC switch, slamming you back to the base lobe and throw a CEL.
On a dyno, I have manually played with VTEC. Just disconnected the VTEC harness and use a 12 volt probe to touch the VTEC wire. When the car was idling, I activated VTEC and the car sputtered like a V8 engine with a drag cam in it....then died and threw a CEL, most likely since it didn't have enough oil pressure at idle. </TD></TR></TABLE>
the ecu does activly enguage and disenguage VTEC under various load, throttle and temperature conditions. It just monitors the oil pressure for sanity reasons. When I ..uhh.. mini-me'd my Accord I modified the ROM to only use 1 wire vtec (no pressure monitoring) and to enguage/disenguage at 3000 RPM no matter what the condition. Obviously it does take a certain amount of oil pressure to successfully enguage the lifter locks to the high cam followers.
Nope...WRONG!
Have you ever had a oil pressure gauge in your car? My D16Y8 make 75+ psi of oil pressure under load and just barely above 2000 rpm. So in that case my VTEC should kick in around 2000 rpm? NOT!
The ECU tells the VTEC switch to let the oil pressure into the valvetrain to turn it on. After that, if there is not enough oil pressure, it turns off the VTEC switch, slamming you back to the base lobe and throw a CEL.
On a dyno, I have manually played with VTEC. Just disconnected the VTEC harness and use a 12 volt probe to touch the VTEC wire. When the car was idling, I activated VTEC and the car sputtered like a V8 engine with a drag cam in it....then died and threw a CEL, most likely since it didn't have enough oil pressure at idle. </TD></TR></TABLE>
the ecu does activly enguage and disenguage VTEC under various load, throttle and temperature conditions. It just monitors the oil pressure for sanity reasons. When I ..uhh.. mini-me'd my Accord I modified the ROM to only use 1 wire vtec (no pressure monitoring) and to enguage/disenguage at 3000 RPM no matter what the condition. Obviously it does take a certain amount of oil pressure to successfully enguage the lifter locks to the high cam followers.
10-23-2003, 09:00 AM
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Re: All Time VTEC.... (Marauder)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Marauder »</TD></TR><TR><TD CLASS="quote">
Nope...WRONG!
Have you ever had a oil pressure gauge in your car? My D16Y8 make 75+ psi of oil pressure under load and just barely above 2000 rpm. So in that case my VTEC should kick in around 2000 rpm? NOT!
The ECU tells the VTEC switch to let the oil pressure into the valvetrain to turn it on. After that, if there is not enough oil pressure, it turns off the VTEC switch, slamming you back to the base lobe and throw a CEL.
On a dyno, I have manually played with VTEC. Just disconnected the VTEC harness and use a 12 volt probe to touch the VTEC wire. When the car was idling, I activated VTEC and the car sputtered like a V8 engine with a drag cam in it....then died and threw a CEL, most likely since it didn't have enough oil pressure at idle. </TD></TR></TABLE>
Listen to Marauder, he knows his chit....
Nope...WRONG!
Have you ever had a oil pressure gauge in your car? My D16Y8 make 75+ psi of oil pressure under load and just barely above 2000 rpm. So in that case my VTEC should kick in around 2000 rpm? NOT!
The ECU tells the VTEC switch to let the oil pressure into the valvetrain to turn it on. After that, if there is not enough oil pressure, it turns off the VTEC switch, slamming you back to the base lobe and throw a CEL.
On a dyno, I have manually played with VTEC. Just disconnected the VTEC harness and use a 12 volt probe to touch the VTEC wire. When the car was idling, I activated VTEC and the car sputtered like a V8 engine with a drag cam in it....then died and threw a CEL, most likely since it didn't have enough oil pressure at idle. </TD></TR></TABLE>
Listen to Marauder, he knows his chit....
10-23-2003, 09:03 AM
#17
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Re: All Time VTEC.... (Galvatron)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Galvatron »</TD></TR><TR><TD CLASS="quote"> The whole idea behind it is to be able to tune the power to 2 separate sets of cams. </TD></TR></TABLE>
Different cam lobes, not seperate cams.
Different cam lobes, not seperate cams.
10-23-2003, 09:05 AM
#18
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Re: All Time VTEC.... (Fowler)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Fowler »</TD></TR><TR><TD CLASS="quote">Fuel economy.</TD></TR></TABLE>
i noticed on my ride when i hit vtec my engine consumes more gas. i cant even spell right damn it!
i noticed on my ride when i hit vtec my engine consumes more gas. i cant even spell right damn it!
10-23-2003, 10:02 AM
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We shorted the VTEC solonid on my freinds Civic with B16A, it ran rough, wouldn't idle long and the emissions were way high we could hardly breath!
It is like having a major hot cam in a normal engine, wouldn't run smooth until high revs so you had to cruise along at high revs in 1st or 2nd round locally or it judders and cuts out because it floods! Interesting though!
It is like having a major hot cam in a normal engine, wouldn't run smooth until high revs so you had to cruise along at high revs in 1st or 2nd round locally or it judders and cuts out because it floods! Interesting though!
10-23-2003, 10:36 AM
#20
Ever been to a drag strip and seen a big muscle car like a charger on the line that can barely stay running at idle [the driver's constntly having to juice the gas to keep it running]. It's because he's using knobby *** cams that hate low RPM's. But once he punches the gas off the line and the cams see high RPM's, then the engine runs great and the cams do their job. VTEC allows you to have the best of both worlds, smooth idle with smooth cams, more power in high RPM ranges with knobby cams.
I've known kids to put VTEC on a toggle switch, one of the most stupid things you can do IMHO.
I've known kids to put VTEC on a toggle switch, one of the most stupid things you can do IMHO.
10-23-2003, 11:37 AM
#22
Re: (Carlo)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Carlo »</TD></TR><TR><TD CLASS="quote">This kind of thread reminds of the idea of using the airconditioner's air to force air into the intake. 
</TD></TR></TABLE>
That's actually good technology. I forgot what USA designed car is coming out or is already out with that kind of induction.
</TD></TR></TABLE>That's actually good technology. I forgot what USA designed car is coming out or is already out with that kind of induction.
10-23-2003, 05:15 PM
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Re: (B2FiNiTY)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by B2FiNiTY »</TD></TR><TR><TD CLASS="quote">
That's actually good technology. I forgot what USA designed car is coming out or is already out with that kind of induction.</TD></TR></TABLE>
i believe its the new ford lightning motors that has that technology
That's actually good technology. I forgot what USA designed car is coming out or is already out with that kind of induction.</TD></TR></TABLE>
i believe its the new ford lightning motors that has that technology
10-23-2003, 05:21 PM
#24
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Re: (CoolKat)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CoolKat »</TD></TR><TR><TD CLASS="quote">
i believe its the new ford lightning motors that has that technology</TD></TR></TABLE>
actually, their prototype (new f150 chassis) uses the a/c compressor to chill the air charge on the blower. its only meant for use in short bursts (10 min or so?) and adds some crazy amount of hp.
i believe its the new ford lightning motors that has that technology</TD></TR></TABLE>
actually, their prototype (new f150 chassis) uses the a/c compressor to chill the air charge on the blower. its only meant for use in short bursts (10 min or so?) and adds some crazy amount of hp.
10-23-2003, 05:22 PM
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Re: (Carlo)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Carlo »</TD></TR><TR><TD CLASS="quote">This kind of thread reminds of the idea of using the airconditioner's air to force air into the intake. </TD></TR></TABLE>I thought that would cause an explosion. I have no idea, though.
</TD></TR></TABLE>I thought that would cause an explosion. I have no idea, though.