Okay, goes like this...

B18c1, t3 pte6152 with ptrim exhaust, full race ram horn, s300, yada yada.

Question is this...

When the vtec is set how I got the car (4200 lower boundary, and 4800 upper boundary), the car kicks over into vtec while the motor is still spooling the turbo. Vtec actually engaged wide open at about 10psi on the turbo, which causes it to lag for a second on it's way to 16psi. You can actually feel the car lag back a second before it hits full boost.

Well, assuming that I'm correct that boost is a build up of pressure in the intake system, and the engagement of vtec helps increase airflow INTO the motor, thus alleviating the back pressure (boost), it's slowing the turbo from reaching full boost faster.

So, I tried pushing my vtec engagement to about 4600 - 5200 rpm, and the car hits full boost wonderfully. No delay, just quick repsonsive boost once the spool starts. HOWEVER, I think my load tables are incorrect because now the vtec doesn't engage until about 6100 rpm, and then it pulls like crazy. How do I tune my vtec tables so that the vtec engages at 5200-5300, like i want it to at full boost instead of so late...

Hope this makes sense, if it doesn't, let me know and I'll try to clarify.

 

Post this in the Engine Management and Tuning section, Im sure those guys in there will be glad to help you out. (thumbup)

https://honda-tech.com/forums/forumdisplay.php?f=124

 

First, thanks for moving the thread for me.

Secondly, since I have this thread up... I was wondering if it would be worthwhile to lock out my vtec on my Type R Cams? I've been reading that a lot of people are just locking the vtec cam lobe on their cars for boosted setups and it works just as well, if not better than actually engaging vtec because of possible traction issues (i've experienced that first hand). I know a buddy who does that on his hardcore 9-second d-series as well.

Any input if this would be a better option vice tuning the vtec point and how I can go about doing it? The plan is eventually to get the car to about 25psi on pump gas and slicks for the track.

Thanks in advance.

 

Well, doesn't seem like I'm getting many replies on this thread, but just an update for any future people who search and find their self in this same predicament..

I adjusted the low boundary cross-over for 14psi (running 16 psi right now) with an RPM range of 5300, and the vtec flicks over flawless and smoothly. No more harsh engagement, just really strong pull being registered by the butt dyno, with a lot smoother transition-- still spinning on streets though

I'm going to be trying to lower the upper boundary (your sort of cruise version from my understanding), as when I open it all the way in 5th and the vtec tries to cross over at 5600, it gets a little sketch and doesn't seem to like it.

I was curious if it would be wrong or complicate the situation if I set the Upper Boundary to a lower RPM range than the lower boundary, ie 4500 at 5psi, or maybe even a little less boost. I'm not trying to go too low on it because I have a Type-R tranny in with some nasty short gears and I've heard horror stories of guys on road trips trying to keep up with other people in 5th gear at 4500 and vtec surging in and out all the time.

Any input or suggestions would be appreciated. If nothing comes my way, I'll probably just tinker with it a little at a time and let any readers know how it goes.

 

haha this is funny


maybe you should try and set your lower and upper boundary the same so the vtec will kick in the same rpm every time

 

Glad I could help entertain you.

In S300, it actually says below on the VTEC parameter that setting the upper and lower boundaries to the same RPM disables VTEC, but I thought about bringing them really close together. Maybe 100 or 200 rpm apart, but I haven't had a chance to try it yet. I was also going to try and just put the upper boundary lower than the lower boundary, since they're both well above what they were originally set at by about 600 rpm; try pushing it back closer to what it was since it worked well that way from the start. For the most part, I'm just doing this by the old trial and error method since I can't find any solid advice to base my adjustments from. Honda-tech search function is almost useless too, imo.

 

Sounds like your on the right path. It is a tough thing to get right if your trying change from low load ( < 100 kpa) to high load, in a high gear with a VTEC transition.

It all depends what feels right to you depending on your driving style, cam selection, turbo, manifold. Just spend some time doing what your doing and see what's right for you.

 

maybe you should read it again it says "to disable the vtec window use the same rpm for the lower and upper rpm" it do not disable the vtec it disable the vtec window

i have no problem with it set the same

but anyway im over it you can do what you want, G/L with the tuning

 

you want vtec to come in as smoothly as possible

for most cars a set rpm over 100kpa/35-40% throttle works well.

with your setup 5000-5500 should work good for vtec with type r cams.

the only real way to know is to get it on a dyno and play with it.

 

Sorry about that, La Hondas. I thought you were poking fun, and I indeed did misinterpret what it said in S300. Thank you for correcting me. Right now the car is down, as I was doing some maintenance things and realized I had a bad tensioner so I'm going to be fixing that here Friday and getting it back up and going. I'll take your advice into consideration and give it a try and see how I like it. I know the true way to do it is with a dyno, but the car isn't ready for that yet and I want a good seat of my pants tune.

Thanks again, everyone.

 

car problems on a b16a 1990 acura integra ls. the solenoid vtec is missing a sensor its green. i have two wires that ar grren and red it that it? oh and my car is not running how it suppost to. when i stop and i put it on 1st and floor it it doesnt oull or when i shift it doesnt pull rpm drops alot.

 

was that english?

 

i think it was spanglish! LOL