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GJF GJF is offline
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If you take your current ignition map and delete everything from 160 across and up. Then shift the entire map up. Then fill the bottom section of the map 1 degree per cell you would have a good base. The ignition map you have now is VERY MILD, a little too mild. It is urrently not one for rapid throttle response. Shift the map and you should gain much more response.

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Old 04-22-2020, 04:53 PM
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RagingBull, it is not fixed lol. Regular FPR will hold the fuel pressure at 3 bar over intake manifold pressure, that's why it has vacuum reference line to it. At idle with vacuum fuel pressure is less than 3 bar, with say 1 bar of boost fuel pressure is 4bar with regards to ambient air pressure. It is called linear fuel pressure regulator.

RRFPR adds more fuel pressure than linear, for example at 1bar boost fuel pressure is not 4 bar but 5 bar of whatever it is set to.
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Old 04-22-2020, 10:30 PM
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Raceboy, thank you for the clarification - my mistake as I did not realize the stock FPR would deliver 1:1 as boost is applied. With a naturally aspirated 3.2, I know the Fuel Pressure is rock steady from vacuum to ambient.
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Old 04-22-2020, 11:59 PM
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Fuel pressure will be lower at idle (depending how strong vacuum the engine makes) and at full throttle it will be at the FPR rated value when n/a (since full throttle with n/a means ambient pressure). Also can vary few kPa since engines are different (some have intake restriction -> vacuum at full throttle), also at what altitude the car is.

With very agressive cams (and thus noisy and very low vacuum signal) it is better to remove vacuum reference altogether in n/a applications as that stabilises fuel pressure and makes for easier idle tuning.
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Old 04-23-2020, 11:22 AM
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Quote:
Originally Posted by GJF View Post
If you take your current ignition map and delete everything from 160 across and up. Then shift the entire map up. Then fill the bottom section of the map 1 degree per cell you would have a good base. The ignition map you have now is VERY MILD, a little too mild. It is urrently not one for rapid throttle response. Shift the map and you should gain much more response.
Thanks for the feedback 👍
Old 04-24-2020, 05:55 PM
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Originally Posted by RagingBull View Post
I believe the stock headers / heat exchangers, J-pipe, and 0.82 A/R housing will all contribute to the lag you are seeing (and the response / feel).

I do not know how the system can adjust fuel pressure with boost as it currently stands. You have the higher power pump and the large injectors but the fuel pressure itself is fixed throughout the range. Typically I understand turbo 3.2 applications using a BEGI RRFPR or similar. That being said, your AFRs would show if this was truly a problem. I would recommend a chat with Turbokraft or Protomotive to shed some light unless our knowledgeable fellow members can chime in.
Thanks for the input 👍
Old 04-24-2020, 05:56 PM
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Originally Posted by GJF View Post
If you take your current ignition map and delete everything from 160 across and up. Then shift the entire map up. Then fill the bottom section of the map 1 degree per cell you would have a good base. The ignition map you have now is VERY MILD, a little too mild. It is urrently not one for rapid throttle response. Shift the map and you should gain much more response.
Any further feedback on the ignition map. If anyone could share an ideal or typical map thatíd be great.
Old 04-25-2020, 03:37 PM
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Every motor is alittle different. It will be close but atleast you would have base to start. Edit your map but save your original for comparison. Dyno time will show you the exact path.
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Old 04-25-2020, 04:32 PM
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Doesn't VEMS have knock control? You should be able to use that as a tuning guide.

PauerTuning (Vic Timpauer) used a J&S that way on a 944, while tuning his Vipec:

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Last edited by John at J&S; 04-30-2020 at 11:59 AM..
Old 04-30-2020, 11:48 AM
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Yes, VEMS has dual knock inputs but that would also require to install knock sensors, route cables and tune noise table.
Should be done by tuner, setting up knock sensing is not something for novice.
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Old 04-30-2020, 01:01 PM
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The brute force approach always works.

I came up with a better way in 1983, while working as a technician in a signal processing lab at Hughes Aircraft.

Shirley and I decided to keep it a trade secret, rather than file for a patent.

That makes marketing very difficult, as you can't really talk about how it works. But, I have gotten carried away a few times and let a secret or two out.
Old 04-30-2020, 02:04 PM
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Originally Posted by John at J&S View Post
The brute force approach always works.

I came up with a better way in 1983, while working as a technician in a signal processing lab at Hughes Aircraft.

Shirley and I decided to keep it a trade secret, rather than file for a patent.

That makes marketing very difficult, as you can't really talk about how it works. But, I have gotten carried away a few times and let a secret or two out.
Heya John (J&S),
I have one of your knock sensors, not mounted yet. Also presently planning on using stock computer with Steve Wong chip.
BUT, I am thinking I may go with a RaceBoy VEMS system sometime in the near future.

So, I'm interested in your comment about trade secrets, etc. I don't understand the implications of what youre saying.
Anything I should know in re. to using the VEMS and your unit?
Old 05-01-2020, 06:29 AM
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Here's a stock 78 930 advance curve. Remember, that figure shows dist, not crank advance. From your ignition map, your timing is very conservative up top.

Old 05-01-2020, 07:24 AM
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It works well and is easy to use.

I'd love to explain how it works, but other manufacturers would say "Wow, why didn't I think of that?"

Here's a video of it on a Mini Cooper, which has a factory Seimans ECU with knock control function. They installed a different pulley for more boost, and added a J&S, and a Snow water/meth system.

In the first run, the water/meth is turned off. The J&S gauge lights up, showing the unit is controlling knock that was missed by the Siemans ECU.

In run two, the water/meth is turned on. As expected, there are no knock detections, showing the water/meth is doing its job, AND proving the J&S was not detecting false knock in the first run.

The J&S was more sensitive than the factory knock system, while avoiding false knock detections. All without setting up a noise table, knock amplifier gain, etc.

https://www.youtube.com/watch?v=tjA8xiPd3SU
Old 05-01-2020, 07:42 AM
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Knock window is essential for filtering out false knock events (since knock occurs only in certain crank angle), VEMS has that. I am not expert in knock sensing like John, but have tuned several cars with VEMS+knock sensors and it also works. Just requires some knowledge of how internal combustion engine works and some experience in tuning in general.
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Old 05-01-2020, 10:04 AM
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Originally Posted by dannobee View Post
Here's a stock 78 930 advance curve. Remember, that figure shows dist, not crank advance. From your ignition map, your timing is very conservative up top.

Thanks appreciate the info. I regard the tuner, so I’m imagining there is a reason for the conservative ignition map and that’ll be knock. So I’m therefore going to assume it’s knocking too early or easily. Fuel is 98 RON and engine specs are in the first post. Perhaps the weak spark (sorta the original point of this post) means it’s hard to advance the timing?

Cheers.
Old 05-01-2020, 05:54 PM
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Advancing timing makes the spark easier to fire, as the cylinder pressure is lower at the time of the spark.

Also, when you adjust timing for no knock, you are retarding the whole engine, just to quiet the cylinder that knocks the easiest.

Last edited by John at J&S; 05-01-2020 at 07:05 PM..
Old 05-01-2020, 07:00 PM
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My tuner confirmed he adjusted the dwell when it was being tuned, and it made no improvements. The ignition map is conservative because of knock.

I’m out of ideas....
Old 05-10-2020, 03:51 PM
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In your first post you say the spark was getting blown out after raising boost. I assume that was solved by increasing dwell?

Increasing dwell increases coil current. Energy stored in the coil goes up with the square of the current. Theoretically, if you double coil current, you quadruple the energy stored in the coil.

Others have analyzed your timing map and have said it's conservative, which can happen when you tune for "no knock".

No one wants knock, but some cylinders knock easier than others. Overall timing is compromised when adjusting for "no knock", robbing power from the more knock resistant cylinders.

Your Vems has the capability to do individual cylinder knock retard. It may even allow you to set timing offsets on a per cylinder basis.

I suggest you learn the system, install the sensors and start tuning/calibrating, or pay your tuner to do some or all of it.
Old 05-10-2020, 04:39 PM
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Thanks John, per the above dwell was adjusted and made no improvement in the situation. The tuner will have made decisions based on safety and I have to trust he knows where that point is. He tunes all sorts of high hp turbo cars so Iím going to leave that decision with him. Honestly Iím not going to learn the system any more than I have as I donít intend to become a quasi tuner. Iíd be happy to explore the possibility of individual cylinder knock retard but donít really want to go back to the dyno until Iíve got a read on why the spark is blowing out.

Quote:
Originally Posted by John at J&S View Post
In your first post you say the spark was getting blown out after raising boost. I assume that was solved by increasing dwell?

Increasing dwell increases coil current. Energy stored in the coil goes up with the square of the current. Theoretically, if you double coil current, you quadruple the energy stored in the coil.

Others have analyzed your timing map and have said it's conservative, which can happen when you tune for "no knock".

No one wants knock, but some cylinders knock easier than others. Overall timing is compromised when adjusting for "no knock", robbing power from the more knock resistant cylinders.

Your Vems has the capability to do individual cylinder knock retard. It may even allow you to set timing offsets on a per cylinder basis.

I suggest you learn the system, install the sensors and start tuning/calibrating, or pay your tuner to do some or all of it.

Old 05-23-2020, 04:08 PM
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