Each click is .1 degree of retard per lb of boost. 12 o'clock = 1 degree.
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Each click is .1 degree of retard per lb of boost. 12 o'clock = 1 degree.
If each click is 0.1 deg, then why does everyone say the car is sluggish at 12 o'clock? The 12 o'clock position should put them right at 10 degrees at max boost which is what most of ran before the BTC. So if each click is 0.1 deg retard, the car should not be sluggish at all, but maybe I'm missing something (which is usually the case).
My car doesn't feel sluggish at 12 o'clock. It feels just like it used to.
Now 4 o'clock... Yikes! Scary slow.
I run at 6 clicks (.6).
Greg
At 12:00 my car feels the same as it did with 8 egrees timing, except for the off boost which is better. I've been told that the retard is .1 per detent, so 12:00 on the knob would be one degree per pound of boost.
Interestingly, I was informed that if the knob is set to no retard (no clicks), then the unit will not retard at any range, being the equivalent of running full stock timing. This is contradictory to what others have posted about it retarding at mid-range even if set to no retard? I was also told that the unit adds timing in low and high RPM and also "affects" the air/fuel basically acting to "re-chip."
Does anyone "know" how this thing actually operates? A good explanation of where in the RPM range and boost what is being affected would be helpful, without giving away any proprietary info.
Has anyone run a timing light on this thing over the RPM band to see what their BTC install is actually doing under load? I still find it odd that when I dyno'd this thing my air/fuel ratios and torque curve looked extremely similar to pre BTC, given what the BTC is supoposed to be doing.
JRCivic, Mr. Detail?
First of all, it does NOTHING to fuel delivery. It only affects the ignition timing. There is no possible way it could. It simply doesn't connect to any fuel-related wires.
Second, don't assume that you get 6psi manifold pressure just because you have a 6psi pulley. I get 8.5psi max manifold pressure with my 6psi pulley.
With the BTC at 10 clickes, this translates to 8.5 * 1.0 = 8.5 degrees max retard = 7.5dbtdc timing at its' most retarded...
NOT
...6 * 1.0 = 6 degrees max retard = 10 ddbtdc timing at its' most retarded.
This could explain some 6psi folks saying that 10 clicks felt worse than pre-BTC 10 degrees timing.
Also, it seems like many people have inadvertantly hooked up to the Tach signal instead of the crank position sensor signal. This too causes loss of power.
If JR added the TPS relay functionality into the BTC, I think they would have a better, more rounded product.
I won't comment on things I'm not sure of. That's why I haven't touched some other points from the previous post.
Greg
Holden-
I don't understand how it could affect air/fuel either, but that info was from a very "direct" source.
As for boost pressures, etc. I agree with you, and I'm not worried that my setup is connected/functioning improperly. The retard function works, it will get more sluggish if I add retard, and if I take away retard, I'll get detonation. Just seems odd that the performance reads nearly identical if even only the timing is being advanced/retarded by the BTC.
As with you, I'm not sure how this thing functions or not, and there doesn't seem to be a consistent story of how it does. I was curious to see if someone does "know" that's willing to share?
Funny. I just postd something about this on another thread. Mine's is set at 12 o'clock and it DOES NOT feel the same as it was before install as the tip-in is defintely more responsive, as cpa pointed out. But I don't know if it's me, but top-end acceleration and speed seems to be a teeny bit slower than before. Anyone?
Adrian.
JRCIVIC, what if you don't hear anything even when you retard all the way to zero? http://www.hostboard.com/ubb/eek.gif
randomwalk101: Remember the BTC has it's own timing curve on top of the boost/retard settings. So if you dont' hear anything, it's because it is already retarding at key points.
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First, I am unaware of any FUEL changes that the BTC makes... like Greg, I do not believe that there are any... there are NO wiring connections to create changes.
However, there ARE timing changes. Under normal operation, the BTC (with retard knob all the way left - NO retard) still advances the timing in the low rpm range, slightly retards in the mid range, and slightly advances in the high rpm range... JUST like a reprogrammed ECU. This is possible because the BTC watches the Crank position sensor. Since the crank position sensor reports its location 21 times during each 360' revolution, the BTC can anticipate when to fire each spark plug... allowing it to advance or retard.
To all on this board using the BTC:
Set it up and tune it the way the instructions say, don't use your own mathematics.
Reset timing to 16' BTDC. Start with the knob in the 12 o'clock position. Test drive the car. If NO pinging or detonation is heard, then move the knob one click LEFT (towards the minimum setting). Drive the car again.
Do this until Pinging or Detonation is HEARD. Once you reach this point, then move the knob TWO clicks right (towards the maximum setting). This gives you a safe margin to drive normally.
If you have an upgraded boost pulley, start your base timing 2' lower for every 2 psi of boost. IE: 14' BTDC @ 8 psi.
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'93 Civic Si H/B with B18C1, JRSC @ 8psi
Best 1320: 12.68 at 110 mph