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Wayne 962 Wayne 962 is offline
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I think I need to quote myself from an earlier thread:

Quote:
Actually, I just read Lorenfb's complete statement, and I just about agree with almost everything he says. I have discussed this issue with Rick Clewett many times (one of the experts on Engine Management systems, and an advisor to the Engine Rebuild Book). He has thousands of hours of dyno experience programming the TEC-3 Engine Management system, and the stock Motronic system. He has told me flat out that the Motronic system is pretty darn good, and installing a TEC-3 on top of a stock engine will not buy you much at all. This statement comes from hours of comparisions on dynos. You'll be able to run more advance, if you install a knock sensor on the 3.2 and have it read by the TEC-3. This is a way to advance the timing without the fear of detonation due to poor quality gas. However, truly significant horsepower gains cannot be achieved without changing some mechanical components of the engine.

Now, changing the chip map (i.e. advancing the timing) will indeed sometimes give you more low-end torque (what is commonly perceived as throttle-response). Also, changing the air/fuel mixtures and ratios according to perceived mechanical changes in the engine (i.e. exhaust systems) and climate will allow you additional room for increases. A California car does not need to be optimized for cold weather conditions and thus can be programmed to run within a specific moderate temperature range. I'm certainly not a super-expert on programming these units (Rick is), so I'm not sure exactly what gains can be achieved from tweaking. However, Rick has stated that they are very minimal. You want to go with an aftermarket engine management system when you make major mechanical changes (i.e. displacement, cams, etc.) to the engine, so that you can custom program the system to adequately match the new configureation.

It's also a misnomer that these EFI systems require hours of dyno time. Rick has repeatedly discussed with me the 'baseline' performance of these systems. With his pre-programmed units (again, based upon his library of programs from hours of dyno time on customer's cars), he can achieve about 95% of the peak horsepower with a TEC-3 system right out of the box (no dyno time). To get that last 5% - yes, you will need several hours on a dyno, mixing and matching the exact parameters to fit your particular engine.

On the other hand, the chips do work. However, as Lorenfb has mentioned, there are tradeoffs. Increasing the timing can lead to detonation --- detionation that if not closely monitored can really destroy your engine bit by bit. The chips work partially because they cut the operating margin (between complete combustion and detonation) a bit thinner than the factory did. You must make sure that you run only high octane fuel (sometimes the CA fuel just isn't good enough) and keep a close watch for detonation when you're driving your 911. Failure to do so can hurt your engine. However, the increased timing can give you more "feel of the pants" acceleration off of the line.

Some chips also work by richening up the mixture at certain points, so that the cars no longer fit an appropriate smog profile. It's no secret that manufacturers have had to make their cars run poorly in the past in order to have them pass emissions. Some chips change this profile to favor performance over emissions. However, my original statement is still true - you can't get truly significant gains without changes to the mechanical components of your engine (early exhaust may help, but it's not really what I'm referring to here).

The bottomline? There is no such thing as a free lunch in this world. You do drugs, and your body/mind will pay for it later on. You add a chip to your car, and you will get slightly better performance, but you'll have to fill up with premium all the time, and you may risk detonation while driving. That said, SteveW's chips seem to get high marks from satisfied customers - we will be carrying them in the catalog in the very near future. For the price, a chip replacement is still one of the best ways to increase off of the line performance. BUT, you're running your engine closer to the edge, which will cause increased wear and possible damage.

There was a previously heated thread debating some of these issues. I didn't quite read it all, but these are the facts of engine life, pure and simple...

-Wayne
I'm not sure what all the fuss is about here. SteveW's chips obviously have many satisfied customers. I'm sure that these customers also know the increased risk that it brings to their engine. Happy customers, can't be too much wrong with that - that's why we decided to carry these chips.

-Wayne
Old 01-28-2004, 05:51 PM
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