SW Chip Experience

[burgermeister]

Just thought I'd post my experience with my recently installed SW chip (91 octane, pre-muffler, US-spec).

Being a paranoid sort, I installed a J&S Safeguard cylinder knock control along with the SW chip, setting it so it did not become active with the stock chip except when blipping the throttle.

The main effect I have noted is that my gas mileage has moved from 21-22 MPG to 23-24 MPG.

Overall, the car feels a little peppier, especially above 6K RPM. DL-1 data does not substantiate this seat of the pants feel during track use, however - the plot below shows four speed vs. distance lines going down the back straight at Waterford Hills, two with the stock chip, two with the SW chip. You tell me which is which! Granted, it was a different day, different weather, I might have been following someone or not, etc - but it suggests the power effects are within the bandwidth of environmental / lap to lap variation. RPMs top out around 6200 for the plot. Black & red are SW chip.

Another effect is that the J&S becomes active more often. It only happens at part throttle, 1500 - 3000 RPM, so I doubt it would cause damage even if the J&S wasn't dialing back the timing. Also it is not strictly A to B, as conditions are different - it is possible to stock chip would do the same with the current conditions. At WOT I have never noticed it becoming active.

So, while it is a nice addition to the car, it isn't quite as drastic as normal butt-dynoed forum posts would have one believe

YMMV

[wildcat077]

What you get with Steve Wong is also outstanding customer support ... you can't honestly expect a chip to turn your car into an instant rocket but since you're getting better overall gas mileage and a peppier feel over 6K it's already above stock figures !

I can't recall how many times i called Steve for some technical questions to which he took all the time in the world to explain to me all the details regarding my queries.I was happy with one of his chips in my 3.2 and i'll be just as happy with the custom chip that he sold me for my 3.6 conversion.
We all agree any little bit of performance counts

Cheers
Phil

[rusnak]

Have you run the knock control on the stock DME setup? That would be your control test.

Basically, you're lowering cylinder pressure when the timing is retarded, so you are un-doing what the chip does and possibly running overly rich.

Personally, I decided to stick with a stock chip after participating in the early discussions regarding this mod.

[chrisbruck]

I like the butt dyno difference the SW chip did to my car. Much more pep on normal around town driving.

[Elombard]

I would really like a SW for my 84 with headers and sport muffler set up for 93 octane which is available here, but I cant justify the cost right now. I have not done much searching are any of the cheap chips worth considering?

The dyno posts at SW site are amazing for the race cars that are custom dyno tuned. Serious umph from a 3.2.

[JJ 911SC]

Originally Posted by Elombard

... are any of the cheap chips worth considering? ...

Buy cheap buy twice...

[John at J&S]

That chip may be leaving some power/efficiency on the table.

Can you get SW to make one with a couple degrees more timing under load, to explore the knock limit?

Tuning for no knock is tuning to keep the worst cylinder quiet, which can reduce power from the others.

[michael lang]

Can someone please explain what exactly a "J&S Safeguard cylinder knock control" does and if I'm doing some upgrades to my car's engine how or what will it do to help my car's engine? I'm asking because once I finish with my car's engine I plan on ordering a chip built to compliment what I've done. I have emailed SW a couple of times and he was very detailed in his responses in a way that was easy to understand. I'm just not quite ready for a chip yet.

[KFC911]

Originally Posted by burgermeister

....So, while it is a nice addition to the car, it isn't quite as drastic as normal butt-dynoed forum posts would have one believe
...

^^^^ This! I've had mine probably close to ten years now...some of the posts just make me . Great product, great service, great guy (imo)...

[burgermeister]

rusnak, I did compare it to the stock chip, though admittedly weather conditions were not the same. My objective was not to do a scientific test, I'm just posting my experience here.

Regarding cost, the thing I like most was the gas mileage improvement. 2 MPG is 10% - with the amount I drive, the chip will pay for itself in 3 - 4 years, which is better than any other $$ I've stuffed into my little German money-sink.

John, I'm going to leave it as-is - I don't really need any more power, nor would I notice another 5 ponies in any meaningful way. I'm happy the car gets better gas mileage and feels faster (even if it isn't much faster), and the J&S removes any fear that some out of the ordinary circumstance will ruin my day.

Mike, a J&S is basically adding a cylinder knock sensor to the car, and it will retard the ignition timing on any cylinder that exhibits knock.
The web site J&S Electronics SafeGuard Indivdual Cylinder Knock Control does a good job explaining it, or user John at J&S could fill you in. I have no affiliation other than I bought one, and I like it.
It's pretty sensitive - when it's become active, I can't hear any knock at all, and as it only happens at light throttle & low RPM, audible knock would not be drowned out by engine noise. Probably overkill on a non-turbo car, but 911 engines are pricey, I track mine, and I like the extra insurance.