PorKen

The LH WOT map is added to the base map (unlike EZF/K), so at WOT you would get more fuel, but cruising, the O2 would pull the AFR to 14.7. LH2.3 maintains it's own ± map in memory, so it would learn to ignore the extra fuel while cruising. I don't know if that would affect the WOT + base map, though.

Strange about the idle speed. It could be the base LH chip was from from a GT. The EZK may also have been, but more advance was added to make up for the GT's maps which are, IIRC, do not have as much advance as S4.

SharkTuning can raise the peaks a little, but it's mostly the area under the curve which gets bigger, and more useful. You have to make physical changes to the engine to increase power significantly.

Someone should develop updated S4/GT/GTS chips (not me, I'm all S3, baby). There isn't that much differences between most setups that the majority of owners have. X-pipe, RMB, done.


With an automatic, you need all you can get at lower rpms, so any extra umpf in the midrange is noticeable.

My '85 5-speed feels faster than my '86.5 auto, even though I haven't worked it over as much yet, because the rpm ranges are more controllable, and there's much less weight in the drivetrain.

DR

Here is the Phil Tong 90 GT Chip Test Dyno which showed no real gains in the later year 928s.

In my 14+ years of hundreds of dynos this is what I would call a "Variance" dyno and shows just the plain normal difference between dyno runs of the same power.

DR

For Comparison sake on the same 928, here is Phil's RMB dyno Comparion dyno at Devek Days.

mark kibort

You are talking to someone that took a stock S4 (with an 85 cam ) and went from 292rwhp to 335rwhp in one session. (coding plug headers, exhaust and intake vents)

That dyno run looks like one run to the next variance. You really need to get the runs so that they mirror on each other before you make a mod.

Mk

DR

Mark,

Too funny, I love you man, but you have an answer for everything to make it skew to your preferred perception!

FYI, both of the car were driven 10 minutes or so after chip changes to "acclimate" the computers for those that believe in that on an S3.

Also I was just an onlooker like everyone else there and had nothing to do with any of the these dyno charts I posted.

On a serious note if you are typically seeing these types of variances on your dyno runs I highly recommend finding a new place to dyno! I spend complete days on the dyno making an average of 40-50 runs a day and I have never seen the wild variances you claim as "normal" with dyno runs. Small variances yes, the wild claims you make, never!

PorKen

Agreed. I would like to have a couple sets of 0.5mm reduced base circle cams made. I think just doing the intake cams would make a big difference.

mark kibort

Here is the 1st time on the dyno with the stroker. 5 hp variance.

Here is a dyno run with 1st and last run listed. 20hp variance. Just running the car a bunch of times, with no changes. This is a BMW with MAF '95

Or, the Devek days dyno with my Ljet. (eRAM on and off) a baseline, then 2 runs with eRAM, pull it off, to verify the small gains over the baseline.

mk

DR

Exactly my point, something is weird about the dynos and/or operators you are using. OR someone is not noticing a subtle change that was made.

Trust me it doesn't take much to make to have a variance of more than 5-8 hp (which I agree is typically deemed the same power in my experiance).

In my experience if the car is at the same operating temp (ambient, coolant, intake, oil) and there is more than 5-8 hp diffrential somebody changed something and didn't notice it.

All it takes is something simple like the fan being moved in front of the car to a different position than prior runs (think airflow into the inlets), the hood not being closed or being closed, or not closed or open the same amount as prior runs and you can see as much as 10-15hp or more differential. Trust me, I learned this the hard way over a decade ago.

It's all in the details.

mark kibort

These are all runs were I was there. The BMW makes the point, as there were no changes, it just got stronger and stronger with every dyno pull.

However, once the car stablizes out, then changes can be made. otherwise, you really dont know what is going on, unless you immeadiately pull the mod and go back to stock to see if the gains remain. again, Ljet seems to be very easy to predict and work with. LH, seems to be a little trickier.
However, I will say, based on the shapes of the chipped curves you posted, that something else is going on. The question is, what. If the maps are not different, then why the change in HP? (i.e. nothing changed!).

Pulling chips out of ECUs and unplugging ECUs, removing power, etc, might by themselves, do something. maybe we need a dyno run of just unplug the computer.

mk

PorKen

In theory, for S4-up, if the WOT switch were not working (common), then the performance chip should dyno quite well.

LH2.3 will go into WOT mode when the load goes over a set point, but the EZK will stay in the cruise map, which would have more advance than the stock cruise or WOT maps.

Mike Frye

Boy, this thread has got LEGS.

DR

Try to keep in mind all of the charts I posted above were "fun runs" at a 928 event, not a product development dyno DAY by me or anyone else.

That could be associated to a lot of variances, when I do real dyno testing we drive the car hard on the dyno for as much as 20 minutes or more before even wasting time on a run. This "clears" it out and gets everything up to proper temp etc. Doing this we always see consistent runs when we start tuning or testing.

It wasn't me that said the maps are not different :-) I have been selling the genuine AA chips (not copied clones, my conscience won't let me do that) for over 11 years and feel pretty safe in saying I have sold more 928 Chip sets than anyone. We always had a 30 day money back guarantee on them, no questions asked. I have only had 3-4 returned for a credit ever. Out of those 1 or 2 of those were just copied and returned (if you are going to do that at least bend the pins so they look like they were inserted in the sockets of the computers instead of a reader :-). We have had a handful over the years that weren't burned properly by AA that customers complained of no gains or negative issues, but once we replaced them they performed to expectations.

Been there done that more times than I can count, with WOT full power runs I have never noticed a dramatic change in power doing this on any 928. Before John invented the PEMs, I used to change chips and unplug computers during a dyno day as many times as a street walker goes thru condoms at night. :-)

Here is a quick example of how even simple things that most people would dismiss can make a big difference. A decade ago we were tuning a later model S4 (might have been a GT) , back in the stone ages all you really had was an adjustable regulator to dial in the fuel at WOT settings. We had been getting consistent power output with each small pressure change over 3-4 runs. After a small change in the middle of the day we had 3 constant runs and liked where we were. We decided to take a break and come back and verify the last setting was what we wanted. After the break and warm-up we made 2-3 runs and everything was still the same. We checked a few things under the hood (didn't change anything) and on the next run we lost 12-15 hp. Ran it again and same thing. We did this 3 or 4 times and I was getting frustrated and we were all scratching our heads. Suddenly it dawned on me, I had left the dang hood open! Closed the hood and boom power was right back where we wanted. 3 more runs confirmed this and we called it a day.

I have consistently always ran my dynos with the hood securely closed and the same large squirrel cage fan blowing directly into the grill to "simulate" air entering the car at road speeds and therefore (at least in my mind) I always seem to get better cooling and proper airflow to the inlets this way.. While you can argue if this works or not, the point is no changes to the engine but a change in the dyno "procedure" can give you big differences in results.

DR

Mike,

Back in the ole days all we had to argue about was chips vs headers.. we've come a long way !!

mark kibort

If you do the "clean out " or normalizing runs, you are doing most all you can to be consistant and accurate. I just remembered something about the BMW runs I showed. That was the eRAM vs the first couple of runs. what we noticed was that the eRAM was out further pointed out of the engine bay. when I put in a dummy tube, (same size and position) suspecting cooler air flow to the inlet, the HP jumped from the baseline almost near the modified runs. In the end the gains were much less (more like 5hp) not the 20hp that the runs indicated. However the runs were all better up to number 3 or so with no changes.

I dont know about the chips, maybe the clone chips are different than the real ones.

It would be interesting to see what was done on the chips, to give those types of gains.

mk

PorKen

RE: dyno variances. On thing I'm think it might be is injector duty cycle. It seems to me that the stock S3 and S4 injectors and fuel pressure combinations are only just enough to support the factory output, plus a little bit more. Putting in more fuel, like going from 14 to 12:1 really taxes the injectors.

On my S3, I found that the injector duty cycle was >90% at max effort after tuning the AFR sub 13.5. I put in a ('87) S4 FPR, 55psi versus the S3 36psi, modified the injector flow map to match on a custom LH chip, and my recent dyno runs stacked right on top of each other, time after time, with no weird AFR variances.


In short: S4s need S3 24# injectors, and S3s need S4 FPRs...