Powerloss for a split second right before vtak
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From: Orlando
Powerloss for a split second right before vtak
Built H22/ PrecisionSC61/ Hondata S300. Fully tuned by a pro on the dyno/wideband
By 5k I'm pegging 10psi, but right before VTEC (5100-5200) I feel a significant hesitation, then when hi cam comes on, everything is back to normal and it pulls smooth and dandy all the way up to 8500. I think I remember a slight dip in the graph, but my tuner ironed it out. What could it be?
By 5k I'm pegging 10psi, but right before VTEC (5100-5200) I feel a significant hesitation, then when hi cam comes on, everything is back to normal and it pulls smooth and dandy all the way up to 8500. I think I remember a slight dip in the graph, but my tuner ironed it out. What could it be?
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From: miami, fl, usa
my tuner tuned a b16 with the same turbo right before he tried to tune my car. We did a leak down #1 19%, #2 15%, # 3 15%, #4 15%, #1 has a bad valve guide. My tuner is clueless to what my problem is. With stock cams he said my vtec should be anywhere from 4800 to 5800 and my motor wants vtec around 6500rpm.
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Re: (McLude2nR)
Okay, here's one of my dyno graphs but it's not my 390 pull which was the latest, but I think it's the same tune. Like I said, I think my tuner ironed it out but the dip is pretty obvious now that I look at it haha. My run is in blue which was at 12-13 psi. Dunc's run is in Red at 16 psi I believe.
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Re: (McLude2nR)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by McLude2nR »</TD></TR><TR><TD CLASS="quote">Most importantly, could this be fatally dangerous?</TD></TR></TABLE>
Depends on what is causing the loss of power.
If you can post the fuel and timing maps, that can narrow it down to if it's a tuning issue or not. Also, is the motor on stock cams?
Depends on what is causing the loss of power.
If you can post the fuel and timing maps, that can narrow it down to if it's a tuning issue or not. Also, is the motor on stock cams?
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From: Oklahoma City, OK, usa
Re: (iBrandon)
Taken from hondata website...
When you get up around a point where your in VTEC and have gone a little past VTEC, you will get a graph like this:
You had put your VTEC at 5000 RPM, and when you hit VTEC it was too soon, as noted from that dip from 5k-5800 you see there. So then that should turn a light bulb on your your head to think "well, it would be nice if I couldn't even feel the VTEC transition, and it was just a straight line" Well exactly. So now, you look at the point where your curve below 5k would hit the line in VTEC above, if it carried on its current trajectory upward, and forward. Take into account its going to not be straight, it will probably round down slightly. Take a good guestimate in your head and then place VTEC where you might think its going to be a good transition. In this case, VTEC will probably come in at 5700-5800 RPM and the graph will clean up nicely. This is a shortcut method, so you don't spend 7 passes trying to find the proper VTEC point. We also don't want to focus on tuning that much above VTEC until our permanent VTEC point is discovered because changes in your VTEc point will have an effect on fueling after VTEC. Now your graph should look like this:
Also, note in the above picture I might be able to bring the VTEC down like 100 RPM to make it more of a perfect straight line? You could do this, but if you do, you won't feel when VTEC comes in and it will be just a noise. I have a philosophy on this subject and I believe the Honda experience should be fun to drive. So what I do is set the VTEC 100, or even 200 higher than its "straight line" position, so that when the customer hits VTEC, the torque jumps up like 10 LBS and the HP climbs steeply up and he gets thrown back in his seat a little bit. It makes the car feel "quick" in that area, and makes it more fun to drive. On 2 liter motors especially, I like to make it steep after it hits VTEC so the customer can chirp the tires just hitting VTEC. Like this graph for example...
See the area I circled? I could have easily set the VTEC 200 RPM lower so that the graph went up less steeply after VTEC, but I wanted the customer to feel the VTEC power when it kicked in. See the torque immediately jump up 10-15 lbs in an instant? The guy gets a little chirp out of it, and gets him excited about driving his car. The job of the tuner is not only to make the air/fuel ratio great and the car safe to race, but to make the car FUN TO DRIVE. BTW, you can mess with VTEC points like this all day long and it does not make the car any slower in a race, because only a beginner would be at that low of an RPM on a VTEC motor racing anywhere.
When you get up around a point where your in VTEC and have gone a little past VTEC, you will get a graph like this:
You had put your VTEC at 5000 RPM, and when you hit VTEC it was too soon, as noted from that dip from 5k-5800 you see there. So then that should turn a light bulb on your your head to think "well, it would be nice if I couldn't even feel the VTEC transition, and it was just a straight line" Well exactly. So now, you look at the point where your curve below 5k would hit the line in VTEC above, if it carried on its current trajectory upward, and forward. Take into account its going to not be straight, it will probably round down slightly. Take a good guestimate in your head and then place VTEC where you might think its going to be a good transition. In this case, VTEC will probably come in at 5700-5800 RPM and the graph will clean up nicely. This is a shortcut method, so you don't spend 7 passes trying to find the proper VTEC point. We also don't want to focus on tuning that much above VTEC until our permanent VTEC point is discovered because changes in your VTEc point will have an effect on fueling after VTEC. Now your graph should look like this:
Also, note in the above picture I might be able to bring the VTEC down like 100 RPM to make it more of a perfect straight line? You could do this, but if you do, you won't feel when VTEC comes in and it will be just a noise. I have a philosophy on this subject and I believe the Honda experience should be fun to drive. So what I do is set the VTEC 100, or even 200 higher than its "straight line" position, so that when the customer hits VTEC, the torque jumps up like 10 LBS and the HP climbs steeply up and he gets thrown back in his seat a little bit. It makes the car feel "quick" in that area, and makes it more fun to drive. On 2 liter motors especially, I like to make it steep after it hits VTEC so the customer can chirp the tires just hitting VTEC. Like this graph for example...
See the area I circled? I could have easily set the VTEC 200 RPM lower so that the graph went up less steeply after VTEC, but I wanted the customer to feel the VTEC power when it kicked in. See the torque immediately jump up 10-15 lbs in an instant? The guy gets a little chirp out of it, and gets him excited about driving his car. The job of the tuner is not only to make the air/fuel ratio great and the car safe to race, but to make the car FUN TO DRIVE. BTW, you can mess with VTEC points like this all day long and it does not make the car any slower in a race, because only a beginner would be at that low of an RPM on a VTEC motor racing anywhere.
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Re: (Finest)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Finest »</TD></TR><TR><TD CLASS="quote">
Depends on what is causing the loss of power.
If you can post the fuel and timing maps, that can narrow it down to if it's a tuning issue or not. Also, is the motor on stock cams?
</TD></TR></TABLE>
Yes I'm on stock cams. I'll get fuel and timing maps up in a little while. However, I'm scared to plug in w/o my tuner around because sometimes when we plug in to the S300, the maps can go all looney and he knows how to revert them.
Depends on what is causing the loss of power.
If you can post the fuel and timing maps, that can narrow it down to if it's a tuning issue or not. Also, is the motor on stock cams?
</TD></TR></TABLE>
Yes I'm on stock cams. I'll get fuel and timing maps up in a little while. However, I'm scared to plug in w/o my tuner around because sometimes when we plug in to the S300, the maps can go all looney and he knows how to revert them.
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From: Oklahoma City, OK, usa
Re: (McLude2nR)
Yes try that, some people like to have a linear vtec, so its nice and smooth...others like to have vtec come in a lil later...so they can feel the "KICK" of the motor when it engages...
you have to do some clean dyno runs and decide where you want it...but definately needs to be raised higher...
you have to do some clean dyno runs and decide where you want it...but definately needs to be raised higher...
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From: new york, n.y., u.s.
Re: (93turbo16)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93turbo16 »</TD></TR><TR><TD CLASS="quote">Like previously assumed, you need to move vtec up. Try 52-5300.</TD></TR></TABLE>
yes, def. set VTEC at 5.3K
yes, def. set VTEC at 5.3K
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