IXLR8

Thanks Mike & Mark,

I found a few links. Interesting reading and nothing new over what I have seen in the past in motorcycle circles regarding chipping.

Boris comments in these threads. Boris claims 3 HP...GIAC claims 13 HP, but that doesn't interest me...its where those gains are that matters. And I'd sooner not see a chip manufacturer's claim...they have a vested interest.

Autothority Chip Question

Still not quite what I am after as testing was done with other mods...
Dyno Testing Results

Too much seat-of-the-pants testing in other threads I've read while searching. I am used to serious lab testing that cuts out almost all doubt other than measurement uncertainty. I'd like to see a dyno chart for a stock 993 and then one for a stock 993 with chip...same car, same day of course.

Stealth 993

Most tuners post HP & torque gaines where the biggest DIFFERENCES are. It may be at 3000RPM, or redline. They are rarely top power gains, so a 12hp chip doesn't make a 270hp car 282hp car. But somewhere in the middle there was a 12hp gain over stock. Most likely will have a few HP on the top end, so you may now have 276hp. Of course DYNO HP is less then crank HP. So a 5hp gain on the DYNO can be 7-10 at the flywheel where Porsche rates the engine power.

Any good chip (CIAC is a good one) will map everything, part throttle, & full throttle maps. You should have smoother power everywhere & more torque. The engine should also feel a lot more lively.

CorrdoBrit

I liked the GIAC chip in my VW Corrado. As Stealth said, livelier on the throttle and approx 10% better fuel economy from the VR6 motor.

Lorenfb

"I am used to serious lab testing that cuts out almost all doubt other than measurement uncertainty."

If that data were available, few if any 'performance' mods would sell!

IXLR8

That I can understand as they do want to "look" good in their ads.

I know I saw chip specs and most if not all were above redline. If redline was say 6500 RPM, the chip ad in the magazine would post 6900 RPM. Well of course...if flow isn't an issue, power increases with RPM if torque doesn't drop off...but I don't want to be reving like a sewing machine in everyday traffic. I look for power and torque gains where it matters to me...from idle to 5000 RPM.

I would think the other way around. RWHP takes the driveline losses into account. At the crank, say 272 HP and at the wheels, say 240 HP.

I wonder why the manufacturers don't do it or is it at the cost of long term longevity? Do they map slightly "richer" to keep things cooler, especially on an air-cooled engine?

IXLR8

Well I know exhaust mods by themselves on performance motorcycles are a waste as far as gains are concerned. Motorrad magazine will pick a motorcycle, a Yamaha R1 for example, and then test 8 to 12 aftermarket exhaust systems and compare the torque and power gains to stock. They then overlay each graph over the stock curves.

Those kind of magazines impress me in that they would show that the exhaust systems tested that companies pay to advertize in their magazine, don't really do anything gain-wise other than a weight loss.

Lorenfb

"I wonder why the manufacturers don't do it or is it at the cost of long term longevity?"

And isn't it interesting that most/all that get sucked-into 'performance' chips
don't ask that too? It would be to the benefit of car OEMs to max performance,
right? It would boost their marketing hype. And that's what they have done,
i.e. max the performance by the use of powerful engine management systems
that incorporate knock control to tweak the ignition timing in real time.

Since all Porsches starting with the 964 have knock control, basically little
to no 'performance' gains can be achieved by using a 'performance' chip.
That's because little to no benefit occurs by tweaking the fuel maps, as many
so-called 'performance chips claim, i.e. The ignition maps have been tweaked
for max performance, given engine load, temperature, and fuel octane by OEMs.
That leaves no real area for improvement without compromising engine reliability.

CorrdoBrit

That is true. In my case the switch from a 2-1 to a 2-2 exhaust was to remove an annoying power dip at 4500rpm (needed for my Rotaxed engined Aprilia to pass DOT emissions). The power delivery is now linear to redline and combined with a freer flowing air filter and the exhaust suppliers chip get a moderate boost in power, per my butt dyno. The real world gains are pretty minimal though.

Stealth 993

Just about all chips raise the redline a bit, they just post the new redline, not the power gained there. Most cars will start to drop off in power at redline. The peak HP is a little before redline.

You are right, Dyno is LESS then crank HP, I fixed it.

Cheap chip tuners just do WOT tuning, as it's easy & safe. Most tuners can do a WOT tune in a couple of dyno pulls, or even at just looking at a few dyno charts with WBO2 readings. It's the part throttle that takes all the time.

Most OEM's are a on the rich side @ WOT. Most tuners will remove a bit of fuel for more HP gains. Tubo cars really benefit from this, but you got to watch EGT readings. Then they will add a bit of fuel & timing on throttle tip in for more response.

In the end, ECU tuning works! Especially on boosted cars. The will be more powerful, & responsive. But on a good factory tuned car, there will not be massive gains. Where chip tuning will shine, is when you do a bunch of other work, like cams, head, & displacement.

nile13

I will say this, and I will say it as an actual engineer with and engineering degree and 12 years of engineering experience behind me.

When people talk about butt dyno, I do not dismiss this "data" out of hand. In an autocross car, if I manage to get 2hp gain on a butt dyno, be it via chip, exhaust or, damn it, cool looking yellow stickers, it does make me faster. Simply by giving me an extra half an ounce of confidence (no weight jokes, please).

I am dead serious in saying this. Now, each of us has their own cost/benefit equation. And for a street car the benefit is usually in the form of enjoyment, not "performance". As a matter of fact, I don't believe that "performance' is of large importance in a street car, period. So if the chip's results are simply perceived gain on a butt dyno and an extra smile here and there... it's well worth it. How much it's worth is a separate questions.

BTW, I made an offer on this particular chip at what it was worth to me at the time and seller felt it's worth more so he rejected it. But I did indicate what it would be worth to me to try it (worth less now that Inka is selling his for $200 ).

PS. I've had Joe Comforti's chips in my E30s and really and truly enjoyed the results on the street, mostly due to the fact that M20B25 would happily rev to redline and clearly became more lively with that chip. Did the car become faster? Unlikely. Did it gain horsepower? I have no idea. Did I need any extra horsepower on the street? Not at all. Did the level of enjoyment of the car increase? Tremendously. Is it similar to, say, a short shifter install where the shifts are not faster, just more pleasent to execute? Absolutely. Of course those chips were $100, so that enjoyment was cheap and easy

IXLR8

Thats fair enough. Its also fair to say that based on that, the chip or whatever mod didn't add to reducing your autocross time. It was confidence.

Unfortunately Mike, I am a really hard sell. I almost always do my homework. In this case, nobody had before and after dyno charts for the conditions I mentioned in an earlier post. Thats fine; I don't have to believe a chip maker's claim.

nile13

Oh, trust me, Alex, I'm a _really_ hard sell. And a great skeptic. But in this case after thinking about it for a while, I understand that most, if not all, street car mods are of little performance note. They are modifications towards more and better enjoyment of the car. Which, of course, can not be quantified.

My thought on autocrossing is this. If a mod can not make me faster but makes me more comfortable, it still often makes me faster. With some notable exceptions, but it generally has proven to be true.

hidden impact

thanks for the banter, guys! free bumps.

since it appears y'all don't think $350 is a good deal (i wouldn't either if i saw the same chip being sold for $200) i will let it go for $300 net price. anything less, it is injustice (IMHO) and i'll keep it.

nile13

OK, I'll take it. Curiosity gets the better of me

AB, shoot me the payment info.

IXLR8

On the first part, I agree. Sort of like billet valve covers...wanna spend some money for something different, that is fine, but don't anybody feed me the line that they are the solution to dry valve covers or that OEM covers warp.

If I spent money anywhere, it would be on shocks, tires and brakes, long before I spent money to make a car go faster. And even then, for my use on the street, even spirited driving, my OEM stock shocks and brakes are more than adequate.

On the second part, I usually expect results for money spent. Otherwise, I'd sooner spend it on gas...or some good beer.