Dip In Torque Curve.

[No Crust Racing]

Hi guys, 3 charts attached to give an overview.

Curious as to the noticeable dip in torque as it builds to max torque. As the car does not have proper engine management, just a tuned rom with an SAFC II to assist, am I safe to assume this is just poor ignition tuning for those cells? There does not appear to be appreciable knock during WOT runs as I considered there may be a a knock issue at that point and the ECU i pulling timing.

CA18DET

Standard cams and gears.

GT2560/S15 T28BB.

RX-7 460cc Injectors.

Z32.

Walbro.

Usual bits like cooler, exhaust, pod etc.

[Dale FZ1]

The dip seems to correlate directly with the boost curve in that rpm range.

Overall it seems pretty good. How does the thing drive?

[STATUS]

Its the result of the gate opening and slowing the accel rate. Normal.

If your boost did not flatten then raise a bit (3700-4600) the curve would be flat.

[STATUS]

haha snap

[No Crust Racing]

Got this on another forum and the answers I've had including these ones have all said the same thing so that's a good sign.

Admittedly it feels like it drives alright, but I remember reading about how too much timing could induce knock which punished torque delivery.

Think an EBC would smooth it out? Controlling gain could help but I wouldn't want it to come on boost any later than it already does.

[R31Nismoid]

Just need decent boost control, fix the lazy boost response and problem solved!

It wont come on any later, it should be coming up sooner (and hence no dip)

[No Crust Racing]

Hmm, think a different boost controller will really make that much of a difference in how fast it comes on? I'm not using a bleed valve, I'm using one of those turbo tech boost taps which "supposedly" holds shut longer so the boost should ramp up pretty much as quick as the turbo can spool for the given amount of exhaust gas - though given it's a spring and ball bearing there's no reason to think it isn't being unseated slightly as boost increases.