SW chip issue put to rest...or not :)
 

Well, I have some good news & some bad news for all you 'chip lovers' out there (of which I am one). First, the good news... I dyno'd a Steve Wong chip yesterday (customized for a sport muffler, premuffler, & 93 octane), and she ran like a 'scalded dog', with excellent HP and torque curves imo. Now the bad news...I did NOT see a significant
difference between the SW chip and the stock (126735358) chip, which frankly, 'shocked the hell' out of me! Unfortunately, I don't have the dyno output in a format that I can post right now, but I will post that info within a few days.
For a brief summary... several of us NC guys spent yesterday morning dyno'ing our cars on a 'Mustang Dynamometer', and we all basically performed the same (HP & torque) runs - a 'wide open throttle' pull in 4th gear from 40 to 105 mph. I performed 6 runs, randomly selecting the SW chip for the first run, and alternating back and forth with the custom chip for the subsequent runs. All six runs produced very nice (and very similar) HP and torque curves, with 5 of the runs showing almost exactly the same HP (184 +/- 1 hp) at the rear wheels. The second SW chip run, was the only run of the six which had any significant deviation, and that run produced 191 HP (at the rear wheels). I cannot account for why that run varied from the other 5. Now, stubborn as I am, I still 'feel' like the SW chip improves the drivability of my car (perhaps it's an improvement in the 'part throttle maps' over stock...or is it a placebo effect?), but as far as comparing 'full throttle' perfomance, the dyno numbers sure indicate that there isn't much difference between the two chips. One other thing...the dyno operator was dividing our rear wheel HP numbers by .75 deriving (for example) 245 HP at the flywheel. He insisted that the (.75) divisor was a factor of the 'type of dyno', when I stated that typically a 15% loss (instead of 25%) was used to calculate this - opinions???
In closing (or is this just the beginning), I was very happy with my cars performance, and although there's no discounting the 'cool factor' of the earlier engine management systems (e.g. MFI or carbs), the 3.2 Motronic system (custom or SW chip) produced some VERY nice HP & torque curves, and more than held its own by comparison. As I stated earlier, I will post the actual graphs as soon as possible, but I just wanted to post this summary, and see what everyone has to say. Let the discussion commence, and I welcome all feedback! Loren, you can even post an "I told you so!", and I won't mind...I'm just learning as I go here and am definitely 'HAVING FUN' :)!

ps. I'm still keeping my SW chip, and would like to find a way to quantify a comparison between the 'part throttle maps'... I've read that a local 'Dynajet' can do a part throttle analysis... Is that 'legit', and worth pursuing?

Cool. Just curious about your torque curves. I know everyone talks about hp, but is it not torque that really makes the difference in accelleration 0 - 60 and 1/4 mile times. Did you notice much or any increased area under the torque curve. Just curious why main focus seems to be on hp instead of torque or increasing torque curves. Maybe I am missing the boat so to speak.

No difference is extremely odd. Do you know if your throttle opens all the way and that the WOT switch engages?

Other than the 2nd SW run (with both the torque & HP curves being a bit higher), all of the runs depict very similar hp AND torque curves... There just does not appear to be a significant difference (both HP and torque) at WOT between the stock and SW chip. Believe me, I'm still struggling with what the numbers 'say', and what I've been 'feeling' in my day-to-day driving. I'll post the graphs asap, so everyone can see what I'm referring too, but the unanimous consensus of everyone present at the dyno was...there's NO significant difference between the stock and SW graphs.

My question is, if torque peaked earlier and increased area under the curve even though it had only 2 or 3 ft lb spikes along the way at peak torque, but could have 5 to 10 ft lb increases outside the peak of the torque curve, would that still not make a noticeable difference in accelleration or 0 - 60 times.

Without the graphs - it's difficult to tell what the full story is. However, it would make sense to me that there would be very little you could do to increase *total* peak HP out of an engine without making major mechanical changes.

Where I have always understood these chips to show their prime benefit is on the low-end of the RPM range - a range not typically well measured in traditional dyno tests.

-Wayne

Doing WOT pulls shows you just that WOT hp....what you should be looking at is how steep the curve is on the "up" side do you see the higher HP and torque sooner?

You need to use a dyno that can give some resistance for the car to drive against.. not sure if that model mustang dyno does that...inertial dynos read peak hp eddy current dynos can tell you hp at different rpms.. and let you play with the fuel and advance curves to maximize the engine output.

what you do is bring the car to say 2500 rpm.. then dial load into the dyno till the power starts to go away.. then go 3000rpm repeat same...

compare those power curves to the stock curve and Im sure you will see a difference....

I would like to see the charts. Otto

I have just finished scanning the printed outputs, but they are still too large to post...I'll get them reduced and post them later today. Steve, I have not confirmed that the WOT switch is engaging (but I will). If that were the case, wouldn't the comparisons still be legit (i.e. not a WOT comparison, but essentially the same 'part throttle mapping') since my foot was planted to the floor on all runs? Thanks again everyone, and I do appreciate everyone's feedback on this!

I dyno'd my car Saturday with Keith and chip differences not-withstanding, his car ran and sounded fantastic. I think he has the GHL exhaust and i forget which muffler, but if you have a Carrera, get this set-up.

My main goal was to get some base line runs so i can experiment with the exhaust a little and smooth out the low end and find the optimal header size for what i want. I am going to weld in an O2 bung for the next time to use his wide band sensor.

TimT, the dyno we were on (my first) put ALOT of resistance on the rear wheels. Under normal driving if i stomp it in 4th, it takes off. On this thing, it was a much slower increase in RPM and speed.

I still had some grunt left at 105mph but am unwilling to run it that hard for high RPM numbers that i am not that interested in. My engine (3.5) has alot of low end torque, but the numbers that the dyno came up with were impossibly high. I guess they will be good for future comparison if i stay on the same dyno, but were unrealistic, which raises some questions.

Paul

Keith, about half of the 3.2s that I have worked with have throttles that do not open all the way, some only about 2/3s and therefore do not contact the WOT switch. Part throttle and WOT are completely different. Part thottle will still be controlled by the O2 sensor to keep the mixture at a stoichiometric 14.7:1 at steady state, and so the ignition advance can only be programmed out to a certain limit. WOT ignores the O2 sensor and allows a WOT fuel mixture at a optimum fuel mixture of 12.6-13.0, allowing a more ignition advance. Some difference has to be accountable, as the WOT maps are just too radically different from stock. Either the performance chip produces less hp, or more, but not identical to the stock. Although each 3.2 engine seems to flow differently from each other, especially with all the mod each owner does, this is what the AFR curve of your car should look like at WOT from idle to 6800 rpm:

http://forums.pelicanparts.com/uploa...1076961307.gif

Owners tell me how they reduced their best a few seconds just with a chip change. Bill Miller emailed me last week with respect to a chip for his 87 3.2. I think it takes a lot to drop 2 seconds off a lap time with an extra 200 lbs in your car:

Hope my referrals worked out. They are the PCA region President and the Chief Driving Instructor so if they like your chip it's good for some word of mouth among the regional racer crowd.

I was happy with the way the car performed in Time Trials yesterday. I had a big guy for a student (200+ lbs) and didn't get to run without him in my car yet I took 2 sec off my best time from last fall. I may do a lap times comparison at our next DE later this month.

Bill Miller

Remember Mike Wong who's G-tech registered a 14 hp average increase? He redid some of his G-tech runs after we took some AFR loggings and redialed in his last chip. He has a freshly tuned 88 with only a Fabspeed premuffler. After cutting out an additional 8% fuel at 6000 rpm (and actually quite a bit less than the stock chip). This was his email:

Finally had the chance to make a few runs today. Got 4 good runs in using
the new chip with the pre-muffler. The average was 195.8 hp, again, using
the G-tech measuring just second gear at wot from around 3k rpm till
redline. Anyways, great work and thanks again for all your work and
help! Ttyl, regards, mike

btw, the 4 runs today were: 185, 207, 188, 203, avg-195.8

previous runs:
stock car and stock chip: 171, 175, 174, 179, 164, 184-last two tossed out,
avg-174.8

stock car and your chip: 175, 190, 190, 198, 174, 199-last two tossed out,
avg-188.3

I'm not sure what to say about your runs, as I'm not an expert on all the different types of dynos, although I have seen that on a dyno, engine hp decreases at the runs progress, probably due to heat soak which will reduce the fuel, and on my recent chips, I've actually programmed additional dynamic ignition timing retard based on temperature so that additional knock protection is provided in hot weather. This could be a possible factor for less hp output. It is not an issue when the car is moving, as the air flow keeps the engine compartment and manifolds cool. Here is a screenshot of the correction factors computed in hp decrease on the dyno as the dyno runs progressed every 15 minutes on this 88 3.2. The stock chip was used as a baseline for the first and second run, and used again on the 7th run for a baseline that computes the decline factor. You can see by the 7th run, peak hp has decreased by 8 hp on the stock chip, and around here is where the decline has stopped.

http://forums.pelicanparts.com/uploa...1076962410.gif

So differences I would expect, but same?

Steve

Thanks Steve (I will read your post carefully a bit later), in the meantime, here are the graphs that my 6 runs produced (in the order that the runs were performed). One other thing, my car's temperature didn't budge throughout any of the runs (w/ the guage sitting slightly below the first 'tic' mark). I've only been able to get her to climb to the half-way mark on the very hottest days of the summer, so I'm in great shape there!

edited: Ha, let me work on resizing these a bit more before I post any of the other graphs... I'll be back this evening.

edited: to remove graph

That is some whacked out looking lines. Were you with the individual who had the 996 3.6 that dynoed at 230 something??? He said something about being with 4 other individuals and in North Carolina. No way a 3.6 C2 that is healthy does only 230 something at rear wheels.

Let's try these graphs again: Here's the first run:
SW #1:

edited: to remove graph

Here's the first run with the stock chip:
Stock #1[

edited: to remove graph

Here's the second run with the SW chip
SW #2

edited: to remove graph

Here's the second stock run:
Stock #2

edited: to remove graph

Here's the third SW run:
SW #3

edited: to remove graph

And the last stock run:
Stock #3

edited: to remove graph

Yes, you must be referring to Ken Charnock. Take a look at these graphs now, and let me know how everyone interprets them. To me, the actual numbers don't matter nearly as much as the delta changes between the runs since I'm primarily concerned with comparing the two chips.

Your running 350 ft lbs of torque or am I miss reading something. Looks like mass confussion at dyno day with those charts and the results on the 996. I agree with you that the lines do not appear to deviate much for the chip at all. Maybe I am not used to reading this type of dyno chart, but something looks amiss to me.

Yes, you are reading the graphs correctly (350+) on the torque curves. Paul mentioned that his torque numbers were impossibly high too (but I don't know what his actual values were). The hp numbers are very close to stock (if I remember correctly), and I would have 'thought' I'd be a bit higher than stock hp with my mods. You mentioned that 230 rwhp was too low for a new & healthy 996...how low? Also, the rpms depicted on the graphs don't represent what my tach was indicating, so now I've got a bunch of ??? regarding the 'actual' numbers depicted. Again, I didn't get too concerned with the numbers since I was looking for differences between the runs. I'm certainly a novice when it comes to dynos, so if anyone can offer some more insight, it would be greatly appreciated. The Mustang dyno owner/operator was raving about how the 'tuners' loved them due to their consistency between runs, but I don't know if he was bs'ing or not. Now this is REALLY starting to bug me, so I might just pay a visit to a local shop that has a Dynojet just to see how the numbers compare.

I am no expert either. If some of the data is off, it would seem to make you possibly question other data. I am not sure what a 3.6 996 should do at the rear wheels. 320 hp on a C2 would seemingly do 270.

Looks like the hp line is still rising on both chips past 5958 rpm, unless it's a really a different rpm as you indicated. It's too bad the runs didn't extend past that point, as usually the stock chip starts declining in power after 5900 rpm, when the new chip should continue ascending out to 6200 rpm or so. There are typically wide differences after that point.

Ain't that the truth! At this point, I don't know what to believe, because the the numbers just do NOT add up. Using the first run as an example, I've got another printout (which I didn't scan), that shows max hp of 184.3 @ 105 mph and max torque of 357.6 @ 96 mph. Well, I was watching my tach (along with the dyno's pc monitor) on all of the runs, and on each run, the rpms were climbing to the 6500+ range as I approached 105 mph. Granted, on the last few seconds of the run, I would concentrate on the dyno monitor (instead of the tach), but I was definitely past the rpm values (5900 stock/6200 SW) that Steve quotes (where the hp should begin to drop off). As the graphs clearly show, my max hp was always as I hit 105 mph (with my tach @ +/- 6500 rpms). At this point, all of these runs just don't seem to display believable numbers, so I think I will try again on a different dyno (after I've confirmed that the WOT switch is engaging). One other thing...although I was approaching redline, I never hit the rev limit (stock or SW chip) on any of my runs. Once again, thanks again for everyone's input!

Mathematically it wouldn't matter what you divided with. You could divide by 100 if you are only trying to determine the DIFFERENCE between the SWC and your 358 chip. It DOES make a difference if you are trying to determine the ACTUAL HP ratings of the chips.

The 358 chip is pretty aggressive from what Steve has written on the BBS concerning OEM mapping. I would guess that most of the difference between the 358 and the custom burn would be mid-range HP and torque?

Well, it would if you divided by 0 :)... I'm just kidding of course. Your're correct though, and as I stated, for comparison purposes, the math (and actual values) don't really matter at all. I was also just a "bit curious" as to what hp my car was actually putting out (with my mods), so that's why I asked about the 'fuzzy math'. On dyno day, I didn't put any significance into the dyno operator's math, and now, I'm questioning the actual dyno results... the results just don't jive with what I 'know' to be true. I'm soooo confused.....

One thing to keep in mind is the relatively correct order the cars fell. By that, I mean that the new 996 had the expected highest number, and Tom's '73 E was the lowest with you slotted properly between them. Paul's 3.5 and my 2.7 were clearly the exceptions and both of them were way down over expectation.

As someone totally disinterested in the "chip wars" I would say that the only possible variable for stock vs SW is a malfunctioning WOT switch. If you find that to be in good working order, then IMHO a chip is probably doesn't buy much new top end performance. Maybe a better butt-o-meter feel or mid-range feel, but not top end.

But is zero REALLY a number? :D

Further, I didn't feel a whole lotta difference between my 358 chip and a custom burned SWC.

Sounds like a dyno day with a competent operator is in your future.

Thanks Hal! Yes, you are correct, and although the cars dyno'd as expected relative to each other (except that I would have thought Paul's 3.5 would have 'smoked' mine in terms of hp and Ken's hp should be much higher). I'm not having an issue with the 'chip comparison aspect' at all. The problem I've got is with the way the hp is graphed...did your (and everyone else's) max hp display at 105 mph, and what rpms were you turning at 105 mph? That's my issue...the rpms on the graph don't reflect what my car was turning, and I should have definitely seen the hp curve drop off as I approached 6500. Not to mention the torque values... You are spot on with your assessment that a chip would not change top end performance however. Saturday was a lot of fun though, and now I'm just more curious than ever...so now I think I will dyno mine on a local Dynajet just for grins. Good luck with your carb issues, and thanks again!

Depends on whether you have a NC public education or not :)...
Counting to 0 is one of our graduation requirements!

LOL...that's funny.

Keith, you forgot your ABC's.. A, B, C.. see I passed :-D

Yes Tim, that's it...to graduate in NC, you need to be able to count to 0, and to know your ABC's...all three of them!

As best I remember, Ken's 996 was the only car to pull to 110 MPH for testing. I am out of town so I can't check the graphs but as I remember I was turning right at 5,800 RPM at 105 and I am absolutely sure that was all I could get!

Was that 5800 from the graph, or from the tach? Also, did any of y'alls (that's "you guys" for the rest of the country :) ) hp curves decline at the end of the run, or was everyone peaking on hp @ 105 (or 110 in Ken's case) mph? When you get home, check, and let me know...Thanks!

I'll check for more of the data when I get home this weekend, but the rpm was from the graph.

Keith,
I was passing 105mph pretty quick when i let off. The graph says about 5900rpm but i wasnt looking at my tach. If we use Taylor's 25% loss rule, that puts me at 246hp, which is about what i would expect. BA has a dyno graph of a twin-plug 3.5 in his book and it topped out at around 250, but it didnt post toque numbers.

My peak torque was at around 3900 and the 395 lb-ft it said i was making is way off. That is more than a 959 at 5500rpm (369).

I think we can agree that these runs will be good only for tuning purposes and future runs on the SAME dyno. I will go back in a month or so with different headers and an O2 bung for wide band analysis. If you want to have a go at Turbo Tune let me know.

Paul

"As someone totally disinterested in the "chip wars" I would say that the only possible variable for stock vs SW is a malfunctioning WOT switch. If you find that to be in good working order, then IMHO a chip is probably doesn't buy much new top end performance. Maybe a better butt-o-meter feel or mid-range feel, but not top end.




__________________
Hal Michael
1970 911 E Targa w/ 2.7 RS spec"

Although the torque numbers numbers are in error, i.e. torque = HP @ 5252 RPM,
K = 5252 in HP = (torque x RPM)/K , the meaningful result is the difference determined
between the chips - insignificant. The results are consistent with other dyno tests
that have been done over the years, e.g. Bruce Anderson's test of six different
perfomance chips indicated no significant differences.

Most DMEs with non-358 chips will probably see a very small improvement with the
performance chips, because Porsche improved the torque output slightly (10 ft-lbs)
with the 082 DME (32K in '87 & 358 64K EPROM in '88/89). For most 3.2 Porsches,
though, as the data further indicate, performance chips are a waste of money even
if the WOT switch was not functioning. Unless you're one of those who drives at
at the redline in all gears all the time.

Many still fail to accept the facts even with this latest data. All the other B.S. that
gets posted won't change the reality about performance chips!