Darklands

Hi Ken,

a friend of me has a S 3 racer.Last month he got regrinded cams from my favorite 928 shop and the car is a complete different beast.

At low rpmīs a little bit less torque but at high rpmīs she goes more like a GT engine.
The car is now a lot faster on the track.

Your cork are the tame cams.I have a broken headgasket in my euro s,so I must fix this first but the "sharp"cams are worth a sin! ;-)

Karsten

OrionKhan

Hmm, isn't 99% of all driving done on the streets under part throttle? Seriously, how often are you driving at WOT on the street? You and a few others race 928s, but the vast majority of the cars are street driven. To disregard gains "only on the street during part throttle" is rather flippant. Most of the driving is done under those conditions. It seems like a notation should be made as to which application the chips are designed for, street or racing.

chaadster

I'm really sorry if I'm being daft here, but I don't understand what you are saying.

First, where does Ken's chart show no change in max HP? I don't read charts regularly, so any insight is appreciated. I know Ken said, "The ignition advance WOT maps are identical, so there's no difference in HP," but I don't know where that's evidenced on the dyno sheet.

Secondly, you seem to concede there is a difference in power and torque numbers on Ken's sheet, by trying to dismiss it as normal variance in dyno runs.

Now, I have never been on a dyno, so I defer to your experience and assume that is true, but why do all post-chip charts I've seen show increases? If variance were normal variance, wouldn't readings go up and down?

Finally, just as another point of reference aside from what Ken has posted here, let's look at Jim Moorehouse's sheets from when he put the Autothority chips in his '88 and did back-to-back runs at one of the Frenzy gatherings, the charts from which are posted on the 928 Specialists site.

I'm curious to know how you read those, i.e. is there no gain there either?

928worldwide

I put the clones in my '85. Now I have them in the Iris 86.5 5 spd. The bottom end is hugely different. Stock the car would spin the tires almost effortlessly, and as soon as the chips went in, that drastically changed. My car runs very rich, and requires a "CLEAR OUT" before normal acceleration under street conditions is realized. BUT, after clear out, and ABOVE 3500 RPM as Mark noted..... My car is MUCH faster than it was before.... And I say the chips are responsible for all of this. If I was a worry wort, I wouldn't be happy with the change from a PURELY STREET perspective. Sometimes though, I drive it like a Porsche is supposed to be driven, and in those moments, the negatives of the chip install are always overcome.

Cosmo Kramer

So saying what we have learned here, perhaps just using Porken's EZF chip is sufficient. Mason mentioned above of a "clear out" below 3500 rpm which is the fuel dump the LH chip is putting in that Ken mentioned, perhaps it is not ideal?

Gtaebr

As a newbie.......who has used search successfully!

Has anyone put more time into "chip development" than Ken. He has repeatedly shown his chip to be superior, and the virtual stock status of the AA and clone LH chip.
This is why he only sells the EZK chip and at $44 it is a bargain.

As a computer "geek" I understand Ken's Bytes....he has more programmed onto the chip that do something, and it adapts to other enhancements. (x pipe etc.)

Seems like an EZK brainer to me.

PorKen

What I put on my chip is an enhancement of what you can do yourself, with a resistor, and disconnecting a wire. (Tweaking EZF, part deux) I felt bad initially charging even $44 (includes shipping), but I intend to have updates when I learn/test more, whereas the APP chips look like they've never been revisited, but they have been charging military contract money for them - since 1991!


Here are the best runs of the eBay chips, and the EZF tweak w/stock LH. (STD corr. approx. -10 here for SAE) '86.5 auto w/X-pipe

PorKen

All this is about the S3 chips. The S4 chips may very well be better made.


Only two of the runs are the clones, two high number runs are stock. The low number runs were likely from high airbox temp (>125°F) retard.

You can get ą5 rwhp variance, run to run, from engine heat, tire slip, etc. Back then, I looked at the runs and assumed that the low runs must be stock, and the high, the clone. But I didn't know then about needing to keep the airbox cool during runs, and that the clone had a stock WOT map.

You can actually see the effect of the WOT map below. The spikes show up on the stock/clone runs. If you smooth those out (with the SharkTuner, for example) the dyno graph smooths out on the top end.

The cruise map does have more advance. (IMO, too much in the red area.)

jcorenman

Ken, I've looked at the S4 chips. The LH chip adds some fuel in the mid-range which is useful, the stock S4 tune is a bit lean there. (This is also mostly irrelevant, since the LH-- with an O2 sensor-- runs closed-loop in the middle ranges and adjusts the fuel to 14.7 anyway). The LH chip also raises the idle from 675 to 775 which is useless except for GT's (because of the cams) which comes that way. And it also raises the rev limit from 6500 to 6800, it's hard to imagine that as a good thing for the average engine. There is no change to the WOT fuel table (which is already too rich for max HP).

The S4 EZK chip also does not change the WOT timing map. So there are no ignition or fuel changes for WOT (assuming of course that the WOT switch is working). However as you noted for the S3 chip there is a bunch of added advance (up to 12 deg additional advance) in the higher-load non/WOT areas, peaked in the 3000-5000 max-torque range-- great for the butt-dyno but also where most engines like to knock.

The EZK has knock detection, with a max retard of 9 degrees. If a sensor is not working then it retards everything 6 deg, that's what the factory figured was the difference between "completely safe" and "safe with a working knock sensor". So a 12-deg change in timing is well beyond what the EZK can deal with.

I tried them briefly in our S4, the butt-dyno said they worked great and the knock-counter went crazy. I am not comfortable using them in our car, and I am very skeptical that the factory left enough "lying on the table" (at least for the S4) to make a one-size-fits-all solution practical and safe.

Sharktuning, with fuel and timing optimized for a particular collection of parts, is a different story of course-- but that's

Cheers, Jim

mark kibort

Its not "fippant" its common sense. (Now that is flippant ) If you want more power on the street, push the gas pedal down further!

If you like having more power for less pedal pressure, then you have a point. If that is your goal, then this is the mod for you. But for me, street or race track, if I want power, I floor the car. Its what the gas pedal is for.

mk

mark kibort

I think Ken has explained his dyno runs.

Often, Ill see a 10 change from the first run to the 3-4th in any dyno session After that, it seems to stablize out and is very repeatable. Then I start making changes and verifying. I also like to put things back to confirm. often times Ive seen gains, only to pull them off and retest to see the same HP without the mod. (disappointing!) If you do two runs, change a chip and see a gain, it might be equal to my doing 2 runs and then waiting 3min and doing a 3rd run. often, i see my highest HP on the 3rd run. Dynoing also has a bunch of other variables. As Ken noted, there were tempurature differences with the two sets of runs. BUT, the main point he made is that by looking into the chips, there is NO differnces in WOT spark or fuel, only in the part throttle range, so there would be no gains expected.

mk

Bill51sdr

I had the Autothority chipset in my 86.5 and the only real "difference" I noticed was a marked increase in pinging during part-throttle acceleration, probably due to the timing advance they incorporate. I was not impressed and later removed them.

DR

Hi Mark,

Do you typically see this much variance (see dyno below) on a back to back dyno on the same day? Since it was a dyno day with a long line there was one run stock, then change chips only, then one run with chips.

This was also done in front of close to 20 928 owners including Marc Thomas (Mr."The Best set of Chips is a set of Headers" :-) so you know if there was any perceived "cheating" it would have been called out immediately :-)

mark kibort

with 2 runs, expecially the first run, yes we see pretty big differences. I also have seen some real strange things going on with ECUs unpluged and re-pluged or batteries disconnected. Much of which I have NO understanding. But what i do know, if i pull the ECU, and then do a speed run, it will miss at 5500rpm for about 15min or 3 or 4 WOT runs. However, you have gains after unplugging the ECU, so that might not be part of it. Bottom line, if the maps are not changed, why would there be any gains?

But yes, Ive seen this kind of variance with 4-5 dyno runs, with #1 being way off the 3-5th and 5th being best. It seems to stablize out with the later runs, so there you can do any testing. with the LJet cars, not so much the case. you can usually split hairs with the variance between all runs.

I have to say, due to the shape of the curves, something certainly is going on to change HP. When I see differences, the curves are all the same shape, and slowly the curves seem to shift up. your curves are very different. too bad you didnt do at least 2 baselines to really see what was going on before and after.

mk

DR

For Comparison here is an 88 S4 that was completely tweaked to the max (by Eral Gillstrom) as any stock early S4 could be. The gains are the least I have witnessed on an 87-88 in over 11 years of seliing he chips, but still had some gains. Again same day, dyno and audience as the 85 Dyno above.

As I have always stated the later year the 928 is the less dramatic the gains are since Porsche was obviously learning how to better optimize the software. So much so that by 89 we deemed the chips ineffective and never actively sold them for any 89-later 928.