High comp b16 low on power
10-29-2018, 03:18 PM
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High comp b16 low on power
I have a jdm b16a p30. I rebuilt it this year with Manley rods and type r (pct) replica pistons. Comp ratio should be around 12:1 (calculated with zeal autoworks calculator). I just got it running good, and took it for a tune. Everything went great with the tune, afr’s are dead on and nothing seemed out of the ordinary. However, it made a whopping 106whp 😬. Considering a stock b16 makes 170 at the crank, I would expect it to be at least 150 at the wheels with the higher compression. Any ideas why it would be so down on power? Head is basically stock besides dual valve springs. Only thing I’m noticing is sometimes it feels like it falls out of vtec. Oil level and oil pressure are good(I have an oil psi gauge). And I tried a different solenoid today and there was no change. No CEL , timing is dead on(distributor and mechanical timing). I’m out of ideas here
10-29-2018, 03:27 PM
#2
Re: High comp b16 low on power
Any possibility that the tune is non-optimal? Experienced tuner with a verifiable track record?
10-29-2018, 03:38 PM
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Re: High comp b16 low on power
Yes he is very reputable tuner. He’s tuned all my friends cars and was recommended to me over the other tuning shop in town. He said everything was perfect on the tune, but it’s very odd to have such low power. He said it seems like something is limiting it in the higher rpms as it stopped making power above 7500rpm. He told me to double check my timing and I did and it’s perfect. I should have a Dyno sheet emailed to me soon and I can post that. Also vtec is set to kick in at 4500rpm to help with the low end power. Do you think that could be too low for vtec to engage?Oil pressure is good and most of the time vtec engages then. But every once in a while it sounds like vtec kicks in around 6000rpm and then drops out at 6800rpm. Seems like an oil pressure issue to me but oil level and pressure are good
10-29-2018, 06:11 PM
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Re: High comp b16 low on power
What tuning software? Get VTEC sorted out and all your problems will be solved.
What are your AFRs at full throttle in mid to top RPM?
What are your AFRs at full throttle in mid to top RPM?
10-29-2018, 06:21 PM
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10-30-2018, 10:23 AM
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Re: High comp b16 low on power
Here’s the Dyno sheet. I’m running hondata s300. I have already checked and cleaned the solenoid screen. I am running sae30 break in oil, just passed my break in period today so I’m going to change it with some 5w30 semi synthetic.
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10-31-2018, 01:01 PM
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10-31-2018, 01:03 PM
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Re: High comp b16 low on power
No cel codes. I’m going to try a different map sensor today. Oil pressure switch is disabled so the only thing controlling vtec is the map sensor and rpm
10-31-2018, 01:23 PM
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10-31-2018, 08:30 PM
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Re: High comp b16 low on power
There is no way a healthy high compression B16A would stop making power at 6700 rpm, even with crappy B16A cams. I suspect your engine is suffering from one of two problems: 1) Your exhaust camshaft is out of mechanical time one tooth... I say the exhaust cam because you have stated that the distributor timing is spot on, and I am going to assume that this means that the top bolt holding the dizzy in place is close to being centered in the adjustment slot. IF it is twisted all of the way to one end of the adjustment slot or the other, then you should examine the position of the intake cam as well. 2) You have a loss of oil volume going to the cylinder head. This has nothing to do with the use of the VTEC oil pressure switch. Moving the mechanical pins within the rocker arms requires a specific volume of oil... just because you turn off the VTP in the tune doesn't mean that VTEC will work regardless of the oil pressure. Likely, you have a main bearing issue and oil pressure/volume is bleeding off there OR an internal oil plug in the head is bleeding off too much volume and thus VTEC fails.
10-31-2018, 08:36 PM
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Re: High comp b16 low on power
2) You have a loss of oil volume going to the cylinder head. This has nothing to do with the use of the VTEC oil pressure switch. Moving the mechanical pins within the rocker arms requires a specific volume of oil... just because you turn off the VTP in the tune doesn't mean that VTEC will work regardless of the oil pressure. Likely, you have a main bearing issue and oil pressure/volume is bleeding off there OR an internal oil plug in the head is bleeding off too much volume and thus VTEC fails.
OP, can you post actual oil pressures under various conditions?
Rechecking the mechanical timing is pretty easy. Post clear pics of cams and crank at TDC1.
Also describe how you checked the ignition timing and the crank pulley mark you aligned.
Last edited by muellersfan; 10-31-2018 at 09:14 PM.
10-31-2018, 09:01 PM
#16
10-31-2018, 09:15 PM
#17
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Re: High comp b16 low on power
Oil level means nothing unless it is down two quarts... and a pressure gauge is typically sourced somewhere on the block (oil pump primary, sandwich plate at the oil filter, or the original "low oil pressure idiot light" switch port just to name a few) and not on the head. This means that the pressure above the head gasket can be reduced from what the gauge shows and the OP is none the wiser.
Adding to the possible list of causes... what about the possibility of the oil pan being crushed up against the oil pump pick-up limiting the volume ???
Looking at the dyno graph posted... there is a good gain at the VTEC crossover point, so it certainly appears that in that case oil volume isn't the problem. Once the oil is warmed up, it may not work as pictured above since it gets thinner when hot. I would look really hard at the mechanical timing. I have seen many cars over the years with mechanical timing issues graph just like this on the dyno.
Adding to the possible list of causes... what about the possibility of the oil pan being crushed up against the oil pump pick-up limiting the volume ???
Looking at the dyno graph posted... there is a good gain at the VTEC crossover point, so it certainly appears that in that case oil volume isn't the problem. Once the oil is warmed up, it may not work as pictured above since it gets thinner when hot. I would look really hard at the mechanical timing. I have seen many cars over the years with mechanical timing issues graph just like this on the dyno.
10-31-2018, 09:35 PM
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Re: High comp b16 low on power
...a pressure gauge is typically sourced somewhere on the block (oil pump primary, sandwich plate at the oil filter, or the original "low oil pressure idiot light" switch port just to name a few) and not on the head. This means that the pressure above the head gasket can be reduced from what the gauge shows and the OP is none the wiser.
Adding to the possible list of causes... what about the possibility of the oil pan being crushed up against the oil pump pick-up limiting the volume ???
Therefore, I think the OP should post the actual oil pressures under different conditions so that we don't have to take his word that the oil pressure is fine.
I would look really hard at the mechanical timing.
11-04-2018, 10:46 AM
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Re: High comp b16 low on power
Yes mechanical timing is dead on. Double checked ignition timing today and it is slightly retarded. I know adjusting the ignition timing will mess with my tune, so I am a little scared to mess with it. I had a friend ride with me and look at hondata while I was doing pulls. The vtec spool flashes on and off while accelerating. And you can actually hear the vtec pins locking in and out
11-04-2018, 08:22 PM
#23
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Re: High comp b16 low on power
Yes mechanical timing is dead on. Double checked ignition timing today and it is slightly retarded. I know adjusting the ignition timing will mess with my tune, so I am a little scared to mess with it. I had a friend ride with me and look at hondata while I was doing pulls. The vtec spool flashes on and off while accelerating. And you can actually hear the vtec pins locking in and out
When I suggested you check your mechanical timing, I didn't mean your distributor. I meant crank pulley to cam gears. However, properly checking your distributor timing can lead to the possibility of incorrect mechanical timing. If you have a stock OE distributor, and you use the "set timing" feature on the Hondata s300, at 16' the top tab of the distributor should be tipped just slightly rearward from centered in the adjustment slot if everything is right. A dead giveaway on bad mechanical timing is the distributor will be moved all the way one way or the other if the INTAKE cam is one tooth off up or down. The exhaust cam can be off and the distributor timing will be unaffected.
11-05-2018, 04:45 PM
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Re: High comp b16 low on power
Once again, all timing is dead on. Made sure of it today and reset dizzy timing as well. Still the same issue. You can’t see it in the Dyno plot because it is an intermittent issue that I can only assume wasn’t happening at the time of the Dyno. Sometimes vtec works flawlessly, sometimes it engages late or falls in and out of vtec. 1st and 2nd seem to always engage it properly. The late engagement and dropping in and out only happen in 3rd and 4th gear. Oil psi gauge is coming off of the port on the block where the dummy light is connected.
i uploaded a video where you can see it engaging late in 3rd gear (supposed it be at 4500 but it happens at 6000). I’ll try to get another video later on showing it falling in and out. (There’s no muffler atm so it’s very clear when vtec engages
)
i uploaded a video where you can see it engaging late in 3rd gear (supposed it be at 4500 but it happens at 6000). I’ll try to get another video later on showing it falling in and out. (There’s no muffler atm so it’s very clear when vtec engages
)
11-05-2018, 05:28 PM
#25