Change VTEC Engagement

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Old May 14, 2012 | 01:00 PM
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Change VTEC Engagement

Did a quick search but couldn't find anything...

But is there anything out there for TL's (Or TL Type S's) that lower engagement point when VTEC kicks in?

Like something along the lines of Hondata for the RSX...I had my ECU reflashed that adjusted air/fule ratios and also lowered the point at which VTEC engages...I think it lowered it to 5200 as opposed to 6000.

If there is a thread already like this, mods you may close this thread as you see fit. Thanks!
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Old May 14, 2012 | 01:12 PM
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We have a ECU available to us.
its called the J&R ECU.

Rodney has played with the vtec engagement points, and found that lowering the vtec engagement from 4700RPM to 4k, the torque curve isnt flat.
While changing it to 5k RPM you get a solid straight torque band.

Acura changed the vtec engagement point for the TL-s', to, you guessed it, 5k RPM.

in other words, our six cylinder is not like any 4 cylinder in terms of gaining power by lowering vtec.
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Old May 14, 2012 | 01:19 PM
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Originally Posted by justnspace
We have a ECU available to us.
its called the J&R ECU.

Rodney has played with the vtec engagement points, and found that lowering the vtec engagement from 4700RPM to 4k, the torque curve isnt flat.
While changing it to 5k RPM you get a solid straight torque band.

Acura changed the vtec engagement point for the TL-s', to, you guessed it, 5k RPM.

in other words, our six cylinder is not like any 4 cylinder in terms of gaining power by lowering vtec.
Thanks!
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Old May 14, 2012 | 01:58 PM
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From: N35°03'16.75", W 080°51'0.9"
Originally Posted by justnspace
....

Acura changed the vtec engagement point for the TL-s', to, you guessed it, 5k RPM.

....

4,950.

http://www.hondanews.com/channels/ac...-tl-powertrain





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Old May 14, 2012 | 02:07 PM
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^ha! justin got pwned.
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Old May 14, 2012 | 02:17 PM
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Originally Posted by SharksBreath
^ha! justin got pwned.
Nah. I thought he was wrong. I thought it 4,700 or 4,800.

But I looked it up and he was right, but I just couldn't resist splitting hairs.


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Old May 14, 2012 | 02:24 PM
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Originally Posted by SharksBreath
^ha! justin got pwned.
Sharky has a type-s with the J&R ECU.
his vtec engagement stayed the same, while mine('06) is getting a bump to 5k.
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Old May 14, 2012 | 03:00 PM
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^yeah but my redline moved up
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Old May 14, 2012 | 04:35 PM
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Our FIC harness had a relay patched in to adjust the vtec level.
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Old May 14, 2012 | 05:04 PM
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I'm confused. Where does it seem like the stock 3G TL 3.2L engage VTEC too soon? Looks pretty seamless to me, and typically (incredibly) flat in true Honda fashion.



Last edited by 94eg!; May 14, 2012 at 05:09 PM.
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Old May 14, 2012 | 08:35 PM
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Our vtec engagement is very very smooth....so smooth that it's poinless. I don't understand why they couldn't make DOHC.

If you can safely increase redline by 500rpm rather than lower vtec. MUCH better results.
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Old May 15, 2012 | 01:26 AM
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Originally Posted by Opel
...I don't understand why they couldn't make DOHC...
The motor would cost a shit-ton more. Think of the price difference between a D16Z and a B16A. Then adjust for 20 years of inflation, then multiply by two (two heads). Plus they were already having trouble putting power down on crappy Truanza tires anyways. lol NM. Lets get a DOHC VTEC V8 already. Yes with 8k+ redline.

Last edited by 94eg!; May 15, 2012 at 01:28 AM.
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Old May 15, 2012 | 07:07 AM
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^BMW status.
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Old May 15, 2012 | 12:52 PM
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Originally Posted by 94eg!
The motor would cost a shit-ton more. Think of the price difference between a D16Z and a B16A. Then adjust for 20 years of inflation, then multiply by two (two heads). Plus they were already having trouble putting power down on crappy Truanza tires anyways. lol NM. Lets get a DOHC VTEC V8 already. Yes with 8k+ redline.
^This. Plus there would also probably be space constraints. Look how large the heads are on modern DOHC VTEC engines like the K-series, and now imagine putting two of those on a V6 and trying to fit it in the engine bay sideways.

Other companies are able to get away with DOHC V6s because they typically have much less complex valve-train arrangements.
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Old May 15, 2012 | 01:34 PM
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Is the 4g awdsh dohc?

although we have high comp sohc =p
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Old May 15, 2012 | 01:59 PM
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sub'd
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Old May 15, 2012 | 02:05 PM
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Originally Posted by DC2many
Is the 4g awdsh dohc?

although we have high comp sohc =p
No. Same poop, different toilet.
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Old May 15, 2012 | 02:13 PM
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^^^
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Old May 15, 2012 | 04:06 PM
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whats wrong with the SOHC design? It functions like the DOHC with less crap and weights less. imagine doing timing belt on DOHC...
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Old May 15, 2012 | 04:14 PM
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here is the vtec engagement video from Rodney....this is from the JnR ECU:

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Old May 15, 2012 | 05:01 PM
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Originally Posted by 94eg!
No. Same poop, different toilet.
haha i was thinking that at first too

well it has vtec for both exhaust and intake lobe I believe but 3g is intake side only
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Old May 15, 2012 | 05:06 PM
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Originally Posted by DC2many
haha i was thinking that at first too

well it has vtec for both exhaust and intake lobe I believe but 3g is intake side only
thats right
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Old May 15, 2012 | 07:02 PM
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Originally Posted by swoosh
here is the vtec engagement video from Rodney....this is from the JnR ECU:
That's cool...but they must be comparing changes on a JNR basemap. It may have to do with their ignition or fuel curves being better for the low-cam (or worse for the high-cam). Since they have no way of re-using the stock Honda/Keihin basemap, it's not really a fair comparison for the OEM ECU. I've never once seen a Honda ECU run with a dip AFTER vtec.

Typically the OEM set's a torque jump after vtec. Especially on the performance DOHC models. This allows potential buyers to "feel" that they are getting something extra during the test drive. Even though they are still loosing out a little in the mid range. Though my personal experience with my stock 05 6MT would have to concur with the dynos I posted earlier. I can't feel any difference in torque before or after. Just smooth pull straight to redline.

PS: DOHC VTEC is tit's when you have a really loud exhaust. Makes SOHC's seem like garbage. For a luxury sports sedan though, the SOHC VTEC definitely gets the job done. Who knows, maybe someday we will get a DOHC VTEC V8 for the streets. Maybe something like this with it's 8-4-2-1 Header that runs the entire length of the car. lol


Last edited by 94eg!; May 15, 2012 at 07:04 PM.
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Old May 15, 2012 | 07:13 PM
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Oh eff it...Here's some eye candy. The Honda HR10EG... ME WANT!





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Old May 15, 2012 | 11:15 PM
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^
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Old May 16, 2012 | 08:49 AM
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Originally Posted by 94eg!
That's cool...but they must be comparing changes on a JNR basemap. It may have to do with their ignition or fuel curves being better for the low-cam (or worse for the high-cam). Since they have no way of re-using the stock Honda/Keihin basemap, it's not really a fair comparison for the OEM ECU. I've never once seen a Honda ECU run with a dip AFTER vtec.

Typically the OEM set's a torque jump after vtec. Especially on the performance DOHC models. This allows potential buyers to "feel" that they are getting something extra during the test drive. Even though they are still loosing out a little in the mid range. Though my personal experience with my stock 05 6MT would have to concur with the dynos I posted earlier. I can't feel any difference in torque before or after. Just smooth pull straight to redline
well right and wrong.....

right as the video was showing the curve after the tune of the ECU....here are the pix on the stock ECU....

Car: 6MT (04 i think) mods AEM intake + Greddy exhaust + STOCK ECU + 3rd gear run:


Same Car and same mods + 4th gear run:


Same Car and mods include AEM Intake + Greddy Exhaust + STOCK ECU + PCD's + JPIPE + 4th gear run:



So if you see all these runs are on the stock ECU with the VTEC engaging at 4700 rpm....and there is a dip from 4000-4200 rpm....the lost HP comes back at around 4500 rpm.....

again if the VTEC didnt create a dip like that then why would it be moved to 4950 rpm in the Type S models ?
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Old May 16, 2012 | 09:12 AM
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Originally Posted by swoosh
So if you see all these runs are on the stock ECU with the VTEC engaging at 4700 rpm....and there is a dip from 4000-4200 rpm....the lost HP comes back at around 4500 rpm.....

again if the VTEC didnt create a dip like that then why would it be moved to 4950 rpm in the Type S models ?
You don't want to compare the base 3.2 to the Type-S 3.5. They are not the same engine. Cam profile, stroke, rod/stroke-ratio & Intake manifold are different between the two, and each play factors in how the engine breathes. Where you set VTEC depends on where the torque curves intersect for both the high and low cams. Different motors always require different rpm. It's like comparing a B16A to a B18C. Same basic engine design.....very different torque curves.

It is very interesting the graphs you posted. I would suspect the mods to the car, even the simple bolt on's, cause the engine to desire a higher vtec changeover. Too bad we don't have a stock baseline of this specific car to compare. If I were to put money on it, I would suspect the CAI has caused a complete shift in the powerband. This means both the low and high cams now make peak torque at a higher rpm. This would require a higher vtec crossover as we are seeing. Of course that is just a guess.

***edit: I also just noticed something. If you look the bottom of the 1st 2 graphs, you will notice a lean condition occurring at the vtec crossover. Can't explain why that is happening, but that might also account for the sudden torque drop. Of course the 3rd graph is running way rich and it's still got that dip as well.

Last edited by 94eg!; May 16, 2012 at 09:18 AM.
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Old May 16, 2012 | 09:22 AM
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^^^ 94eg!

in retrospect, i think the 3rd graph is for 6MT with AEM CAI and Greddy Intake with the JnR ECU tuned and hence its running rich....in this graph the VTEC engagement is not changed/controlled by the the JnR but the stock ECU....
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Old May 16, 2012 | 10:06 AM
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Ah, that makes much more sense. Thanks.

So is the JNR thing a piggyback that runs along side the stock ECU?
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Old May 16, 2012 | 10:43 AM
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^yeah it plugs right up to the stock ECU. very easy...each harness just plugs into the correct port and they're all labeled for easy identification.
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Old May 16, 2012 | 01:42 PM
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Old Nov 14, 2012 | 02:36 PM
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So is the stock v-tec engagement on the TL 4700 rpm?
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Old Nov 14, 2012 | 02:47 PM
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^for the base TL, yes.
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Old Nov 14, 2012 | 07:45 PM
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I think its 4700 and some change....

Justn, didnt they change the the VTEC on the base after 06?
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Old Nov 14, 2012 | 09:42 PM
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^need answer to that please..i have 08 base
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Old Nov 15, 2012 | 07:08 AM
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no, i think its the same.
all base models are 3.2
so that would dictate the same vtec crossover in all base cars.

onion rings, why do you need an answer so badly?
(just curious to know what you're up too)
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Old Nov 15, 2012 | 07:14 AM
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since i got my exhaust...i've been thinking about a few things on making my car faster...ahaha...

im tempted to pull the trigger on the RV6 V3...and pcd...

these mods may be down the road...so im curious....i just wanna hit 300 whp thats it maybe a bit more

Edit: Without Super Charging
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Old Nov 15, 2012 | 09:58 AM
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^^^ so what has any of those mods gotta do with VTEC engagement?
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Old Nov 15, 2012 | 10:45 AM
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He's probably thinking more mods = vtec lower. Inline 4 thinking.
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Old Nov 15, 2012 | 08:35 PM
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One thing to note with the Type-S is that it has vtec on the intake and exhaust valves where as the base has only on exhaust. Not sure if that would really be a reason for them to change it but who knows...
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