this is taken from the SCCA 2010 rule book involving the L15a7 in FF


9.1.1. Formula Car Category Specifications
a. Honda PN: 14620-RB1-010 Arm Assy, rocker.
8. The VTEC system must be stock. The VTEC activation valve
must be stock. The HPD ECU will activate the VTEC at 5200
RPM. Honda PN: 15810RB0-G01.
h. Valves
OEM valves must be as used in the Fit.


being it says the vtec system must be stock, and says the ecu will activate at 5200 i would say i disagree with goobers disagreeing with 555


update: found this gem on ToV

On the road, the Fit's 1.5L SOHC 16-valve 4-cylinder (117hp@6600 rpm, 106lb-ft@4800 rpm, codename L15A7) has been fortified with "real" VTEC, meaning it actually has dual discrete lift profiles that the intake valves follow, and the difference over last year's "mild" VTEC motor (which switched between 3- and 4-valve operation) is immediately noticeable.

 

^^^ that is what the ruling say, yes.

but with regards to when and when not to engage vtech outside of that sanctioned ruling is a free-for-all to would be tuners

 

yes... but the post wasn't about tuners ability to change vtec engagement it was about when vtec engages on our stock cars. There was some incorrect info in this tread incorrectly stating the GE8s vtec to work like the GD3s and it's simply not true.

 

Well, I hope you weren't thinking I was one of the people implying it worked the same as precious versions.

There is a person that said the ecu determines when to activate, depending on multiple factors... so, the question then is, does that mean it doesn't activate at only a given RPM, but as needed. So, it could activate at 5400 one moment, then at 2800 the next? What if it uses the MAF sensor and detects that it's not getting enough air at low RPMs (like at high altitudes)?

 

Less as a comment on when VTEC does "X" but more of one on Why VTEC does "X"

The VTEC in a GD3, which actually uses speed density instead of a MAF, is using only 4 intake valves to increase velocity to (0.6 Mach or greater is the target for most cylinder heads) through the intake ports, decreasing turbulence and atomizing fuel more efficiently.

This fills the cylinders better and with a more thorough dispersion of fuel charge temps decrease and more torque can be created.

Because when the other valve is open it effectively doubles the port size with a proportionate decrease in flow velocity, which below the threshold RPM hurts cylinder filling compared to a single smaller valve and port.

So, if VTEC is variable, all 8 valves are opened when the volume and pressure (which determines engine "load" = grams of oxygen/revolution/cylinder) justifies it based on sensor feed back.

 

Well, while I won't say I fully understand it... I will say, I'd rather go with a simpler answer. It gives the engine enough air to combust the gas as best as possible.

I have been thinking since my last post about how else to respond. In the last few minutes I came to this thought... the Rules are for the teams using the engine, they have to keep it "stock" as provided by HPD. But, does it say that "stock" from HPD actually is the same as a road car? HPD can tune the engine anyway they like, and that would be considered "stock" would it not? Since "stock" only means "as provided by the manufacturer."

On another note... I'd like to see someone (anyone, reputable) produce a dyno chart of the GE8 engine. Is it the same as the chart shown in one of the previous links? If so, then what can account for the change in the torque graph at about the 3000-4000 rpm section? Something must have changed. I feel that it is the VTEC's cam profile change.

Ps using an iPod sucks.... I miss-spelled 'previous' and it auto-corrected to precious! Grrr

 

Stock VTEC is 5400rpms on the GE8. Agree or not, hook up a VTEC indicator LED as I did and you will see when it activates. With the J's reflash I just had a couple weeks ago, VTEC now activates at 5300rpm. I asked J's if they would alter that to about 5000, but they were hesitant and the reason because they would need to alter other tables as well and really the only way to get numbers is to dyno. Main reason I said just lowering VTEC is not really a good thing. Sure you might feel something, but the engine is not running at optimal settings.

 

何でヴィテックを　いじろう　としてるの？　この車わお金をセイブするためじゃないの？　早い車が欲しいな ら、　やっぱり、スポウツカー　を選ぶべき　だったんじゃん？

 

I'm having so much fun it should be illegal. I got my digital rpm switch running again and wired up another relay. Now I have repeatability to begin testing. So far I have tried 4500 and 4800 rpms. 4500 is just too low, second gear goes lean with high load and trips limp mode. 4800 is awesome in first gear and okay in second and third but fourth gear she goes lean due to aero load at 95mph. This is just too much FUN! It only takes 30 seconds to reprogram the activation rpm and thanks to my relay system it is extremely easy to give control back to the ecu.

 

Honestly i would take the guys word for it that has hooked up the vtec light. Rather than someone who "feels" that it "could" engage at 3800.... but Goobers will continue to argue his side, to spite the facts being thrown at him left and right. Honestly my short time in this forum (reading alot of old posts) 555 has posted tons of good info and Goobers continues to try to shoot down facts with his feelings.

 

Wow, so, you're against my "debate" of the subject? While he has provide much good info in many topics, there's no guarantee he's right either... at least, not until its confirmed by either somehow viewing the engine itself (not via a signal cable made through a DIY) or by documents by Honda or someone as reputable.

Did I come out as negative as you and claim they're WRONG? Last I checked (and I haven't edited it).. I only said I disagreed.

But hey, if you want to be so negative, that's fine.

BTW, your facts... aren't as complete as you think they are. The SCCA's rpm setting is a setting the SCCA decided in order to match the performance of the outgoing Kent engine. There are multiple documents on this, from Honda's HPD. Does it mean it's different from a road car? no. But it doesn't mean it's the same either.

Consider this... if VTEC engages at 5400 RPM... and the HP curve is almost topped out shortly after, the torque curve is in fact dropping already, it doesn't seem to make sense. On the other hand, at about 3000 rpm, you notice that the torque curve starts to level out, but suddenly starts rising again... why is that?

But hey, I guess I can't engage you on a simple "possibility" can I? I'm just wrong (according to you).

re 555sexydrive

To be honest, I wonder, maybe it's not VTEC you are actually detecting.

https://www.fitfreak.net/forums/2nd-...vs-prm-vs.html

Referencing some of their info... there is a change in HP (in the 5k range), but except for the Weapon R dyno (last pic), it seems the change is further up in the 5550 or 5600 rpm. In the Weapon R dyno, it "looks" like its a little lower, in the 5400 range. But since the graph isn't too specific like that, I can only say "looks."

 

I'm posting this as a separate message.

I'm done with this topic.

Being insulted as such, isn't a way for me to spend my time.

If you can provide definitive proof beyond a DIY that VTEC is engaging at 5400 rpm, okay. I'll happily admit I'm wrong (future readers might have to settle for this post). Until then... whatever.

re 555sexydrive

I don't mean to single you out, it's just that you were used as the "proof" against me.

 

It's definitive. It's in the Electronic Service Manual. The very circuit that activates at 5400 is the rocker arm oil pressure solenoid. The hydraulic mechanism that switches from one lobe profile to another AKA vtec. To me that is the only thing that should be called vtec. Everything else is not vtec. The 3v swirl effect switching to 4v is not vtec 'to me'. The article you referenced says what I suspected. There is 12v, 16v, and 16v with higher lift aka vtec. Remember the ge8 has vtc. Vtc is the likely cause of the changes in torque early in the powerband. That article has me contemplating how to make shorter intake manifold runners. It's either the runners or the head itself that is causing the breathing problems above 5800. I wonder if a machine shop could essentially chop out the middle portion of the lower manifold and weld it back together .

 

Okay, I lied, I'm back.

Lyon, I can definitely accept that.

I'll just add, that while you consider only the solenoid activation as VTEC... for me, they both pretty much do the same thing (putting in simply), control the amount of air coming in to produce the best ratio of air to fuel in the chamber. But, that being said, I'll keep that to myself and won't go around telling people to call both "VTEC."

I came across this... FlashPro Help

maybe you can make use of their instructions... though I'm guessing you'd need access to the ecu.

 

You're on the right track, but the ECU uses the injectors to control the AFRs.

The valve events are used to control flow velocity and cylinder filling,

They are changing VE, not A/F, with VTEC.

 

As Lyon pointed out, with the GE8 there is also the addition of VTC, the i in iVTEC. With the cam able to alter its angle to different degrees you get a much smoother powerband versus a stationary cam. So the gain you are seeing at 3000 or whatever is more than likely due to a shift in cam phase. Honestly I don't know if the L15 2nd iteration has as much as the 50 degree cam phasing of the K20, but being that I owned a 5R Integra previously, I could definitely see (FEEL) a difference in power output when I had the cam angle set at different angles at the same RPM. I didn't have access to a dyno so I was relying on street tuning and what the datalogs were telling me.

Don't worry, I don't take offense or anything. I know for sure that I'm seeing VTEC activation as I am hooked directly to the pinout on the ECU.

 

Ok, I've been thinking about it, over and over about the 5400 RPM engagement point. The only conclusion the seems reasonable (to me) is that after that point, the toque must have a severe dropoff when using the low cam profile and there isn't a benefit in the torque before that point (in the road ecu mapping of the car).

That being said, I'm curious to how much the SCCA's restrictor plate and ecu mapping (along with the 5200 RPM VTEC engagement) changes the torque output.

Since the SCCA isn't necessarily choosing that point for "smoothness" like for a road car, then it may or may not mean the "smooth" switch over point has moved from 5400 RPM.

But still, I wanna see that graph!!! If we're lucky, it'll show an increase in torque (hopefully, across the board). And by "we" I mean Lyon, since he's doing a lot of this already.

 

I was having problem with OBD code 2649 and 2647 plus my VSA light turn on and engine goes into limp mode since last week when I first install my Boomslang wiring harnesss with AEM F/IC-6 to activate the VTEC earlier...

I had sent SOS signal to Lyon asking for his guidance both on his DIY thread and via PM, unfortunately he had not been checking fitfreak for a while...

so after many research with help from my friend Chris (who also post here under user id Slimchriz) I manage to find the solution using the AEM F/IC-6 and Boomslang wiring harness,

NOTE:
Ups, after real world testing I now understand that 2 relay will be needed after all...
will post more once I bought a few fuse for this relay (have the relay but not the fuse needed)...

I will post soon

 

For anybody interested in doing this modification, (and since this thread by Lyon do not have any pictures anymore), I have the DIY and the wiring diagram posted here:
https://www.fitfreak.net/forums/2nd-...ml#post1348611

 

If you had a full diagnostic scope hooked other car on the dyno,, I'd bet that somewhere just above 3000 rpm,, the engine puts some spark advance in before it activates the vtec solenoid to balance the upcoming shift in mixture with the extra air.

Similar issue,,,, I have a 1.8 BMW with a dual runner intake, the length of the intake changes from about 14" to about 8 inches at 4300 rpms. It changes the timing at about 3500. Its a pretty extreme change in runner length and volume when the "disa" valve opens. Kinda like an old 4barrel carb opening up..