PorKen

Thanks Fred. A bigger HP number would have been great, but torque really 'gets things moving'.

How individual cylinder tuning helps torque is perhaps best shown by the safety or hot graph. The red line shows when the coolant/engine is hot-hot-hot and the overall advance level is down to the same or less than stock. New torque is found around 3500, 4000, and from 4500 up with no knocks.

Also note the effect of overall advance to the peaks vs. at 5000.

Hilton

So whats next? On the hunt for an '89GT yet?

PorKen

@Fred - eventually I want a set of cams for my S4. Don't want to mess with full length headers tho.

@Hilton - the framework is all there. Fairly quick to retune for GT/GTS. Just need to borrow one for a week or two.

Too bad Keith W. sold his GTS manual - can't make new maps with autos, too much variability.

mark kibort

Fred , what do you mean, "the auto box dies". 4200 is a nice peak torque zone, but more importantly, its the power you need to look at. 250 to 275hp is available and at a pretty moderate RPM, so its very usable.. ..... just have to be in the right gear. you think about using the first peak at 3200 and the power available is a lot less. (but good for partial throttle acceleration on the highway when you dont want to floor it and you still have decent power )

its all about the power curves and running that engine up over 4200rpm when ever you need acceleration

Mongo

Ken, another bump after a month of stasis for this thread. Could you explain how sport mode works on your chips?

PorKen

Sport Mode: over 3000 rpm or with heavy throttle the O2 loop is bypassed and the AFR is enriched a little (into the 13's). It stays in this mode until the load returns to a highway cruising level, regardless of rpm. Combined with no decel injector cutoff, this makes running at higher rpms much more pleasant (and responsive). With the O2 loop in control the AFR is up in the 15's which feels anemic. Releasing the throttle, injector cutoff makes it stutter and wheeze.

With the new ignition update at part throttle the outer cylinders (1458), which have intake runners that don't flow as well as the inner ones (2356), run just a touch more advance. At higher rpms they run a bit more. This makes the engine rev really nicely and the transition from WOT<->part throttle is imperceptible. Of course at WOT all cylinders now have their own learned/mapped advance level which means no bog at any rpm for floor-it-anytime-fun.

Mongo

Thanks! I have an injector question too...

Will Bosch 0280155715 injectors that are 24lb work for these chips? They have an impedence of around 13-14 ohms which qualifies them as high impedence. They are also 4 hole types used on Ford V8s and are blue in color.

ptuomov

So you have cylinder specific learned wot ignition maps? Care to post what the knock limited optimal timing is for each of the cylinders?

Mongo

Found out the injectors cross reference to the Design II mentioned a while back. These aee Design III so I bought them.

PorKen

Cylinder specific-ish? Individual cylinders by rpm and inner/outer group, but in each group cyls have to share the worst cyl's retard. (Each cylinder ramps in and out of its retard level at each rpm which acts like interpolation.) As the engine heats up, though, most all knocking cyls take about the same level at that rpm, although #6 is special.

Speaking of which, I checked the spark plugs recently after a lot of WOT runs...for the first time there were no micro-beads on the #6 plug.


This is the static WOT map - learning adds to this. Upper dark line is outer cyls 1458, lower is inner 2367. Green is mostly 1 and 8 IIRC, red is mostly 6 and 7. (RPMs shown are approximate.)

ptuomov

Thanks.

It makes sense that #6 is a real problem, since it both has a well filling intake runner (I believe) and 90-degree exhaust interference from cylinder #5.

Here's a question: Since the long-runner cylinders seem to handle less advance, can I conclude from that that they are also filling better? Or is it that the center cylinders always run hotter? My guess is the former, having looked at some aftermarket ECU fuel maps for a late model 928. If so, someone looking to make a custom intake manifold might want to shoot for 30cm or 12" runner lengths. Easier said than done, of course. Or maybe it's just that those runners are a lot more straight, but then again runners #1 and #4 aren't that crooked.

FredR

Tuomo,

I have been trying to unravel the "mystery" of why I have what appears to be quite a problem with No6 cylinder controlling timing. I have tried a colder [WR6] plug on cyls 6/2 and it did not seem to make much difference but I intend to try a WR5 such as Ken uses just to close that loop.

What I suspect happens is that as we add things like the x-pipe we get more out of the motor but the question is "how non linear are those gains". I have questioned why we get such a scatter of AFR values in a given cell when using Sharkplotter and I can only conclude it is in part due to the [mal] distribution of air flow in the runners. When I get pings they are invariably on either 6 or 2 with a preponderance on 6 [in the ratio of about 4 to 1] albeit same order of magnitude. Yesterday I did some research into my sharktuning history and then I noticed something interesting- at some stage the knock pattern seemingly changed. During my initial attempts at sharktuning it was invariably the inner cylinders that pinged but I saw such pings on all 4 inner cylinders and the lions share were on No 2. My recent history is in fact different with most of the knock activity on No 6 as indicated earlier. The only thing I can put this change down to is a step change in behaviour after I installed the plenum cover spacers I run with and just maybe this mod favours 6 & 2 with a bias to air flow through 6. Thus if timing is on the limit perhaps the gains are masked by the EZ pulling back timing a couple of degrees across the board and then you lose the benefit to some extent of the gains made.

Ken's excellent work shows a clear demarcation between timing for the inner group and the outer group and the timing compensation patch he has developed now gives me something to play with. Similarly, for reasons I do not understand, the stock mapping system has many rev bands at low rpm's but relatively few "where the meat is". It makes sense to have a capability to deal with those troughs when they occur.

I believe I am fighting two problems here- gasoline quality and the heat. I believe the local refinery is using too much LPG in the gasoline to obtain octane certification in the lab testing. However, I have a feeling that the C3 component is way too high and this flashes off in both the forecourt storage tanks and the car's fuel system as it circulates/is heated in use thus lowering the effective octane rating by the time the fuel is burnt. The garage forecourts reek of petrol fumes during summer season.

All good stuff!

Rgds

Fred

Mongo

Ken,

FYI, you may want to update the spark plug requirement on your site.

The Bosch WR5DC is obsolete and is now superceded by part number 7992.

Also, what do I gap these at?

Mongo

Bumping.

Aside from my prior question related to spark plug gap, my cam timing is advanced 2 degrees on my car to take advantage of the torque boost for my automatic transmission. Do I have to set it back prior to installing the chips? Also, if I do not, how would the car be affected (positives and negatives)?

PorKen

The 'octane adaptation' and WOT learning code will compensate for the slightly higher compression.

2 (crank) degrees isn't much, anyway.