PorKen

No.

How 'bout a poll?

https://rennlist.com/forums/928-foru...up-tuning.html

Hilton

This post has part numbers of injectors *with* the groove.

https://rennlist.com/forums/8391175-post14.html

The 24# plastic ones with grooves are expensive, and there are a few alternatives without grooves which are much cheaper - Chris (Landseer) fitted some and pics/posts about it later in that thread. The grooves can be added with a hacksaw blade.

No, the ones I linked in my previous post are too big - they're 30-32lb (depending on who you believe). I'll remove that link to avoid confusion in Ken's thread.

I'm wondering whether the Sharktuner actually reads those scales from the EPROM, or whether the rpm scales are hard-coded in those apps. If they read from the ROM, it *might* be possible to sharktune against your chips (e.g. for those who will be swapping in bigger cams to their S4).

jcorenman

Here's my data points FWIW: For a mostly-stock S4 (early-88, x-pipe, cats) with stock maps and a calibrated MAF, the injectors reach 100% at the top end with an AFR of around 11:1.

Sharktuned, same everything, injectors are around 95% at the top end with an AFR tuned for around 12.5:1.

GTS, completely stock, just touches 100% but with an AFR of around 12:1.

Cheers, Jim

PorKen

I'm pretty sure it reads the whole image.
There is quite a bit of special code for the ST, especially communication stuff that is not in the stock BIN, which I am using.

My scope is stock with X-pipe. If folks want more, they are on their own.

Not trivial to program, but it would be a nice feature in the ST to have user adjustable MAF and RPM scales.


This is what 9 rows for just 296-424 MAF units does, plus extra RPM cols.
Nice, smooth injector plot (red). (S3 stock 24# with S4 FPR.)
Over 6000 rpm is really tough to control. No smoothing BTW.
This is about 310 rwhp, SAE.

S3



Compare to the 'rough cut' of my '88 with 24#.
Jagged injector plot, going rich over 6000 as it goes 'off map'.
Roughly 290 rwhp, SAE. Same MAF, same top end MAF units, -20 hp.

(Blue is flappy closing.)

S4

PorKen

Note that both those plots are on the same time scale, same road, in 3rd gear...and yes, the '88 is a slug in comparison.


IE. maximum values, and divisions.

Having a bunch of unused MAF units for supercharged monsters is a waste, if all you are tuning is a X-pipe (and injectors).


Anyplace there is a big jump in MAF units (and RPM), the more error and randomness creep in.

John Speake

Yes, the whole image.

Such a special LH map would be possible, as we have done this prevously. We shied away from making customer adjustable maps generally available.

jcorenman

I think the instability in injector PW that you are seeing is a reflection of instability in the MAF signal, and nothing to do with how the maps are arranged. There are no big map discontinuities in that area (in the stock maps at least) that would cause problems for interpolation, and we don't see that with the Alpha (MAFless) system. I am pretty sure it is a MAF effect, and mostly harmless.

My theory is turbulent flow into the MAF caused by the less-than-optimum transition from the airbox to MAF. But I don't have much data to support that-- just that it is reduced with the EIS-style cold air system.

cfc928gt

Ken, are you saying that the stock chips will work okay with 24# injectors and perhaps even better?

PorKen

It probably is MAF and/or RPM instabilities.

I found that these are amplified by the LH, especially at high load and RPM, when the MAF rows and/or RPM cols are too far apart. Where the load is slowly changing is usually clean, but around the torque peaks is very unstable. Unlike at lower RPM, at high RPM/max HP, MAF voltage changes are slight, so any error is interpolated badly.

I found that any spikes limited the amount of advance that I could safely run. They also made for inconsistent dyno results. If you look at my S3 dyno runs above, the huge torque hump past 4000 is totally unique. I don't believe a consistent 310+ rwhp SAE is possible with a S3 with stock (or ST) scaling. Raising the advance will just produce knock. (Note my runs were on 89 octane, and are extremely consistent.) At the highest S3 MAF output, my MAF rows are only 4 units apart.

Some areas of the LH maps could not be tuned unless I moved a RPM column to that area. Either too rich, or too lean. Adjusting on either side of a bad area would make the sides off, and/or make the bad area further off, and often create a spike.

Stock EZ chip...with a LH chip adjusted for 24#.

You can run 24# with the stock LH chip - the LH will compensate for it - but it may start roughly, and will likely be very rich past 5600-ish rpm.
HC emissions may be borderline, if you need to pass these.

Tom. M

Just from my personal experiences.... I ran 30's in my GT when I had the rear turbo (stock lh/ezk). cold starts were a bear and had to feather the throttle to keep the car running. Once warm, they behaved well.

The 24's in there now (both with turbo and after turboecotmy) ran great in all conditions and doesn't seem to be pig rich at the top end when I floor it... (but I haven't dyno'd s with them in). I just left them in there after removing the turbo since the car ran so well with them. No differences in fuel economy (but will eventually do some sharktuning to optimize). Only drawback is that the fuel economy gauge is way off (it uses pulse width).

jbrob007

As my son likes to say... "thats just not fair!!!" Picture is worth a 1000 words!

Thanks

jbrob007

Come on now... dont get all pissy just because my 86.5 is faster than your new & improved model

So, is the reason it cant breathe because of smaller intakes...? guess you didnt hit me hard enough

Tom. M

I would have to say it is the restriction of the smaller intake valves on the S3s... Even the supercharger guys see higher boost pressures than the S4 guys..but don't necessarily make more power...

Just an off hand question....is there room to upsize the 3 intake valves?... suppose larger valves in conjunction with the higher lift (pre GT cams) of the S3 would be interesting ..

Hilton

Hmm.. from memory of others' knowledgeable comments, isn't 6000 rpm about the point at which ring flutter starts in a stock 5.0L?

PorKen

Rings may be fluttering past 6000 on - some - peoples cars, but it could be because fueling and ignition are uncontrolled.


On S3s, 6000 is the point where the fuel and ignition maps end. (S4-up go to 6200.)

At that point, the LH/EZ go to a straight RPM/load calculation (or the last known value plus RPM/load or something).
This is the point where typical dyno graphs drop off a cliff.

My S3 maps go to 6400 (11 ).
HP does not start to drop off until - you guessed it - 6400. (6700 rev limit for manuals.)

S3