Ok, so are the ports supposed to start opening at 3800, or be completely open at 3800?

I have mine starting to open at 3800 ish and once it hits 3800 I feel a slight drag, or like I am hitting a wall, and then pull. This didn't happen when I had the ports removed. Can I correct this by adding a little more fuel, or removing a little? Dyno tuning soon, just got to get a few more things in the car.

Thanks!

 

Thats the 3800 RPM hesitation. Its been covered a lot and is talked about in the FAQ.

 

Hmmm, thanks.

Uh, well, to my original question.

Guess I should have mentioned to check my sig, or cardomain.

I have electronic Aux. activation. I was wondering if I should be setting the pump to kick on before, or after 3800. I don't have a tach for in the engine bay, so i usually have my GF hold the car at 3800 and I tune the pump to open then. Should I be setting it to open slightly before so that by the time the RPM hits the 3800 and the secondaries kick in, the ports are already open?

I was thinking about having her hold it at 3500 and then setting it then. My RPM climb pretty quick, and I figure if I set it there, that gives the car 300 RPM to get the ports open.

Thanks for the input though. I have delt with the 3800 hesitation. my current hesitation is caused because I don't think I have the aux opening at the right time.

 

You have electronic switching, so the best thingyou can do is get on a dyno. Make a run with them closed the whole time, and then open the whole time. Where the lines cross is where you want to open them.

In the mean time do it at 3800.


BC

 

Thanks.

I am going to set them to start opening before 3800 so that by the type the secondaries kick on, they will already be open.

 

On S5's the solenoid valve is activated at 3850rpm. They should open pretty much straight away.

It's more likely to be the 3800rpm hesitation when the secondary injectors come on. The ports opening shouldn't cause this. But since you can adjust the opening point, it's easy to see whether it's the ports or the injectors. Just set them to open at say 4500rpm, and if the hesitation occurs at 3800rpm it's the injectors, and if it occurs at 4500rpm then it's the ports.

The ports should not be set to open based on what the injectors are doing. They're completely unrelated, and don't effect each other. There is only one correct rpm point where the ports should be opened, and the best way to find that is using a dyno as described above.

A cheaper but more cumbersome method would be two find an empty straight section of road and do some acceleration testing. Here's how I'd do it. Set the port opening point at 3000rpm and from a rolling start in second gear, measure how long it takes to accelerate from say 2000rpm to 7000rpm. Now increase the opening point by 500rpm and repeat. Keep increasing the rpm point until you find which one provides the shortest measured time.

 

Thanks NZ. I had them opening at 4.2k. . I had my girlfriend watch my SAFC and hold the RPM at 3700. Then I set it to open right then, using the variable resistor to fine tune the opening.

No more slight bogging anymore. Once I get everything setup on my car it will be dyno time, and tuning from there.

Thanks for replying.