theory on boxster bolt on problem - 986 Forum - The Community for Porsche Boxster & Cayman Owners

eslai · 03-20-2006, 09:24 AM

Quote:

Originally Posted by turtle

The solution for the Z was to reflash the ECU disabling the knock sensor and the fail safe mode activator command, as well as a dummy plug that gave the MAF a constant intake temp reading of forty below.

Hmm.. That's pretty nuts. So you completely fake out the computer on IAT and it never can do any sort of compensation based off it.... that's not as bad as disabling the knock sensor though! Did you have some other form of auxiliary knock control or are you just waiting until the car coughs up a piston?

Yeah, there is a bit of a "buffer" in what Nissan thinks is safe and what the average tuner thinks is safe, but still... completely disabling one or the other of those two sensors is a recipe for disaster.

turtle · 03-20-2006, 09:38 AM

"Yeah, there is a bit of a "buffer" in what Nissan thinks is safe and what the average tuner thinks is safe, but still... completely disabling one or the other of those two sensors is a recipe for disaster."
__________________________________________________ _______________

I can see how you would think that.
BUT notice that the MAF reading is set to factory default failure code - forty below. Colder the air, the denser the air, less particles can be suspended in it - so the the ECU compensation by running the richest it's program will allow. After that, just make sure your mapping is right so that you don't run too rich.
As a matter of fact, fouling plugs has been our only problem. We haven't had a single lean out in about 20 cars over the last 3 years, and at 52k miles my Z is just fine.
As for GIAC..I don't know. That is why I am posting, to gather info. It's always just a matter of electronics these days. If someone knows where I can buy Porsche diagnostics for out CONSULT station here at the dealership our Techs could figure a lot out.

eslai · 03-20-2006, 09:55 AM

Ahhh.. I see, yeah that is rather cold, and sounds really vehicle-specific to me--every car has its own tricks and I guess that's a Z thing as I've never seen anyone do that before. I used to tune and install AEM EMS systems on Eclipses and so I'm pretty "textbook" when it comes to tuning--trickery like you described makes me nervous.

KRZTACO · 03-20-2006, 10:14 AM

What GIAC and Revo need to due is a custom on-site tune such as HarmonMotive does for the WRX and EVO. http://www.harmanmotive.com/

You should put on the headers, intake, exhaust, etc. then take it to them for a custom tune on the DYNO.

HarmanMotive takes advantages of all your bolt-on's so all the peramiters are maximized for HP gains and running solid with no hick-ups or CEL's.

My friend had a 2004 WRX with intake exhaust, larger intercooler, larger turbo, etc. it ran so rich he would shoot sparks out of the exhaust (Converter was removed too) and it ran really crappy. After his tune with them, his car gained like 20 hp and it ran just like stock NEVER any problems after the tune.

KRZ

986Jim · 03-22-2006, 05:35 AM

Quote:

Originally Posted by turtle

"Yeah, there is a bit of a "buffer" in what Nissan thinks is safe and what the average tuner thinks is safe, but still... completely disabling one or the other of those two sensors is a recipe for disaster."
__________________________________________________ _______________

I can see how you would think that.
BUT notice that the MAF reading is set to factory default failure code - forty below. Colder the air, the denser the air, less particles can be suspended in it - so the the ECU compensation by running the richest it's program will allow. After that, just make sure your mapping is right so that you don't run too rich.
As a matter of fact, fouling plugs has been our only problem. We haven't had a single lean out in about 20 cars over the last 3 years, and at 52k miles my Z is just fine.
As for GIAC..I don't know. That is why I am posting, to gather info. It's always just a matter of electronics these days. If someone knows where I can buy Porsche diagnostics for out CONSULT station here at the dealership our Techs could figure a lot out.

I hear what your saying about the 350z. My father and I are bulding a 3.5L 95 Maxima for drag racing and were doing the same thing. The knock sensor on the VQ35DE is totally a drag and is best eliminated, but this is rare and only applies to that motor. I would never do this to any other car. It just seems that the stock programming in the VQ computer is designed the say way as others are saying. For retards that put water in the tank, they have to make the car still run. We are getting around the stock computer with an emanage ultimate and some time on the dyno. I wouldn't see this as even an option on a Porsche.

On that application yes it works, but I would never apply that logic to another platform.

RandallNeighbour · 03-22-2006, 07:05 AM

What a great thread. I have nothing to contribute beyond a THANK YOU for all this back and forth knowledge about tuning, etc. I'm learning a lot! :dance:

turtle · 03-22-2006, 08:35 AM

PorscheDoc - if you are some way offended I apologize, or perhaps I am reading too much into it. The way you describe a knock sensor is only half the job for the VQ45 sensor. Intake air volume and temperature play a big part for it as well. All the chips were modding exactly as you specified - but as soon as more air started coming in, it would jump all over the ignition curve - even with new maps from such suppliers as Technosquare and Stillen. In this case, with all the extra fuel flow, it would be hard to see knocking unless you are in a high boost FI application.

We are a dealership that has been in business over 30 years, and we have been in tuning ever since previous owners son bought a new 260...tens of thousands of hours of performance work has been performed here, and all the techs that do it are master certified, and many of them race, track or strip, and sometimes both.
The mods to the knock sensor and the MAF have always been performed on cars that have already been remapped and have had extensive airflow work done on it. Perhaps you thought I was advocating it as a mod in and of itself. Not the case.
986Jim - good to see someone who has actually done it. I thought that it may be VQ45 specific. We recorded an increase of around 10% over the modded baseline on all of the Nissans we have done it to.
We only work on Nissans and Fords though, so the reason I posted here is to see if anyones has used it on a Porche.

It may or may not work, but untill someone tries,we won't know. I am waiting for LNS Motorsports, who seems to be the Porchse builders around here, to comment. I will let you guys know what goes on.
Cheers,
Turtle

Porschekid · 03-22-2006, 08:43 AM

What car are you tuning a VQ45? The 350Z uses a VQ35. I've never seen Stillen tune much of anything... they usually just put their brand name on other people's products like Jim Wolf Technology.

turtle · 03-22-2006, 12:22 PM

Quote:

Originally Posted by Porschekid

What car are you tuning a VQ45? The 350Z uses a VQ35. I've never seen Stillen tune much of anything... they usually just put their brand name on other people's products like Jim Wolf Technology.

whoops wrong key. in case you haven't notice I am not the best typist in the world, hehe.
And you are right about Stillen, but they are a good source, and will refund in case of error. When we recommend somehting the vendor is almost as important as the product.

986Jim · 03-22-2006, 12:48 PM

Quote:

Originally Posted by turtle

986Jim - good to see someone who has actually done it. I thought that it may be VQ45 specific. We recorded an increase of around 10% over the modded baseline on all of the Nissans we have done it to.
We only work on Nissans and Fords though, so the reason I posted here is to see if anyones has used it on a Porche.

Were in the neighbourhood of ~300whp N/A and working with a 150whp shot nitrous from an NX kit. At 2500lbs race weight cut/lexan were looking for 12's flat @ around 115-116mph and 11.5's or so at 120ish mph with the nitrous. We'll see how it goes. This is transplanted in an older 95 Maxima

The VQ35 with the knock sensor disabled was able to take a 200hp shot of nitrous on a fully stock motor. It pulled the 03 Maxima to 12.1 @ 116mph as a best time and it survived that shot for many passes. We were mostly worried about the tranny but nothing ever happened. With the knock sensor working it lost a lot of time as it always pulled timing. Fart in the car lose 10 deg timing, it was brutal.

If your interested here is a vid of me and him running... (my talon vs. dad's maxima)
http://www.etdracing.com/jim/jimjr_vs_jimsr.wmv Times are a little outta date, but whatever.
I'm 29 dads 58 and were still both act 17, interesting pair we are...

PorscheDoc · 03-22-2006, 03:41 PM

Turtle: I am not offended in any way, I know on the internet it is hard to deduce a person's attitude vs. standing talking to them face to face

Like I said before, I am no tuner (porschephd on the other hand has more experience than most out there), but I know enough to be dangerous, and I think that disabling any sensor through the ECU to get an engine to do what you want it to is a poor method. Stephen does a ton of tuning with Motronic, Autronic, and Motec and I know he doesn't disable anything when tuning. We also are a GIAC dealer, and work extensively with Garrett at GIAC, and know how they tune. I have also seen my share of tuning that has been far from desirable.

Karl