PPC £999 Challenge 2011

[cogboy]

I had a little 'off' in my mk1

A 'little' off? I think you must be magnetic old boy, coz every Mk1 you drive seems to be attracted to steel fences.

Your car will probably have dissolved by September anyway. Get the Porch going again.

[BarronMR]

Mod update - Just set the timing to 15deg(ish) and moved the AFM 3 clicks leaner, and all seems well. Ended up having a bit of a duel with one of those Mitsubishi 3000GT twin turbo 300+BHP thingys and it easily held its own so can't be too bad can it?

Well, I hit the dyno on saturday. 184whp.

Did try non-acis but fueling and timing were already good so I didn't mess.

I've got plots overlaid at home of acis vs. non-acis but I'm still needing to give it some thought as it looks like my acis wasn't working in the 1st place.

But in gerneral with the valve in place and with it fully cut out, it gave more power all over the rev range but only a couple of hp at peak. Was good to see the topend of rev range pick up some. My car wouldn't idle with valve out but that could be adjusted for.

More details to follow.

[Nickp]

But in gerneral with the valve in place and with it fully cut out, it gave more power all over the rev range but only a couple of hp at peak. Was good to see the topend of rev range pick up some. My car wouldn't idle with valve out but that could be adjusted for.

More details to follow.

Do you mean it was jammed open? And gave more power everywhere?

[BarronMR]

Well, got a bit carried away the night before dyno and fitted an inlet end with the acis valve chopped out, effectively removing acis fully. With that the car felt to pull cleaner, throttle response felt better and last few thousand RPM felt to have more power.

Problems were that the car didnt like to idle and was a bit juttery at very low RPM, bear in mind if Im driving normally im in 5th gear before 30mph and can stay in 5th up any hill I've tried. So from this I assume torque has been lost from the bottom end of rev range, which we expected.

Anyways on the 1st dyno run still with no acis car ran 185whp (can't remember exact figs), fueling ranged from mid 13 AFR's to low 12's at topend.

Unlike usual 3vz plots there was no double peak in torque ie acis change over point.

Anyways switched back to standard acis setup and the plot stayed the same shape but lost a bit of torque all over the range.

Now for some reason it didn't click in my head that maybe the acis control plumbing wasn't connected up right or due to the dyno using the acis pipe to take a reading for inlet pressure caused non-operation.

Conclusions - only that more than likely above acis activation point with the valve fully removed you may gain and hold more power at top of rev range.

If I get time tonight I'll post pics of acis vs. non-acis and compare to my old plots.

Will be retesting this once I get manifolds on and get shut of the toyota y-pipe, hopefully another 30whp to come yet naturally aspirated.