996 ROW tune

[jaykay]

How are things running for you? What engine / engine displacement and airbox are you using? What mass air flow sensor type did you end up using to make this work? If it's a Cayman MAF housing did you end up fitting a 996 sensor to it?

[ike84]

Originally Posted by jaykay

How are things running for you? What engine / engine displacement and airbox are you using? What mass air flow sensor type did you end up using to make this work? If it's a Cayman MAF housing did you end up fitting a 996 sensor to it?

JK, she's running great. Its a 2.7 00. No issues with the tune, AFR runs at 14.7 at cruise and 12.5 at WOT. The intake is all custom - 82mm bosch TB, larger MAF housing(3.25" diameter sourced from BMW) with OEM MAF sensor, run through rear firewall into a 3.5" Y pipe with twin high flow dry filters, all mated with 3.5" silicone tubing. It's a bit unconventional, I admit, but it works well. The only issue is intake temps get hot, but I have a fix - boring out large holes in the OEM spoiler body to channel air into the trunk when the spoiler is raised (I've added a gt style rear wing so the stocker spoiler doesn't do much for aerodynamic stability anymore). I've not ever had the chance to Dyno it but she pulls hard and revs fast (the first thing I noticed after flashing the new tune actually was how much quicker it revs). LTFTs are -17% on each bank so if all else is equal I should be making quite a bit more power than OEM, probably in the 230-240 range. I will also say that with the OEM airbox and the SAI out, it's a hell of a lot easier to work on things like the fuel rails/injectors I did a bunch of posts on those mods, under the DIY section, I think I titled it 82mm TB. Let me know if you have any other questions.

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[jaykay]

Thanks, that sounds like quite a set up. I will search your posts for some images! I will have to read up on Bosh fuel injection but those AFRs sound like stock which is quite amazing given all your changes.

It is interesting you are working on a spoiler intake. Many many years ago when the Boxster first appeared on the road and I knew nothing about them, I thought the spoiler element coming up was to facilitate some sort of cooling airflow.

what actual mass airflow sensor did you use with your set up.....would imagine that a 996 one would create the least issues.

[ike84]

Originally Posted by jaykay

Thanks, that sounds like quite a set up. I will search your posts for some images! I will have to read up on Bosh fuel injection but those AFRs sound like stock which is quite amazing given all your changes.



It is interesting you are working on a spoiler intake. Many many years ago when the Boxster first appeared on the road and I knew nothing about them, I thought the spoiler element coming up was to facilitate some sort of cooling airflow.



what actual mass airflow sensor did you use with your set up.....would imagine that a 996 one would create the least issues.

I used the original 986 OEM MAF sensor from my boxster. The two are the same part # between the 986 and 996.

There is something worth noting here - these modifications (along with the 2.5" exhaust I did) were phase 1 of a much larger project, which is a low pressure high flow twin turbo setup.

After much research, I came to realize that our ECUs were incredibly advanced for their time and are still more capable than nearly every aftermarket ecu setup (save for a motec system, but that's a different discussion). The setup I designed would produce 300-325hp, which in turn pushes the airflow parameters and fuel requirements outside of the stock maps for a 986 though so I needed a workaround (stock maps have +/-20% built in on either side on nominal to account for varying conditions). However, this is perfectly in line with the 996 performance specs. So, the simplest thing to do for me was to simply convert the ecu maps to those of a 996. Even without the FI I had a feeling that my power production would be high enough to stay within the 996 maps by making the intake and exhaust modifications, which it is.

The beauty of our ECUs is that it has no idea what displacent motor you have. It uses 2 primary inputs (airflow in and which side of lambda your exhaust is on) to dictate two outputs (injector pulse width and ignition timing). We could talk for hours about this...point being you just have to make sure that the inputs are accurate for the ecu to do its job.

To that point, you have to match the tune to the intake. The 996 maps are based on MAF sensor readings through a larger diameter housing. So, If you keep the MAF housing diameter stock (regardless of where the sensor is actually located) you don't need the 996 maps. This would even be true for a low pressure single turbo setup. If you upsize the MAF housing though, either with a cayman airbox or a custom setup, a tune will be required (either a 996 tune or, if your car is 03-04 the anniversary 986 Spyder tune will work as well).

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[barkinfool]

Ike (& any others!)--

I have a question for you since you've done quite a bit of research on the ECU. I have an '02 986S which unfortunately experienced the dreaded IMS bearing failure in 2020 (even more unfortunately because I had invested in a proactive LN Engineering replacement bearing which failed in <20K miles!). Anyways, my Porsche mechanic suggested I consider putting in a brand new 3.6L short block while we were at it and he rebuilt the header, top exhaust valves, etc.... Cost was pretty close to getting 3.2L short block, but performance to me seems much better & worth the $1.5K difference. Anyways, we made no changes to the airbox though am running K&N & better exhaust for years. Just wondering if you know /think if a 3.6L tune makes sense (again I'm now running 3.6L base engine with original (rebuilt) Boxster 3.2L header on original tune using the 20% variance). If yes, suggestions who / where I should get the tune?

[ike84]

Originally Posted by barkinfool

Ike (& any others!)--



I have a question for you since you've done quite a bit of research on the ECU. I have an '02 986S which unfortunately experienced the dreaded IMS bearing failure in 2020 (even more unfortunately because I had invested in a proactive LN Engineering replacement bearing which failed in <20K miles!). Anyways, my Porsche mechanic suggested I consider putting in a brand new 3.6L short block while we were at it and he rebuilt the header, top exhaust valves, etc.... Cost was pretty close to getting 3.2L short block, but performance to me seems much better & worth the $1.5K difference. Anyways, we made no changes to the airbox though am running K&N & better exhaust for years. Just wondering if you know /think if a 3.6L tune makes sense (again I'm now running 3.6L base engine with original (rebuilt) Boxster 3.2L header on original tune using the 20% variance). If yes, suggestions who / where I should get the tune?

If you adjusted valve specs, a custom tune would likely be best. Good luck finding someone in the states who can actually do that though (I'm taking about in person Dyno tuning, not the aftermarket crap that adds 15hp or whatever).

If your dme setup is running without throwing codes, I would do 2 things. First, look at ltft's. Use the VE of the 3.2L and see if the LTFTs are positive enough to account for the additional displacent. Second, have it Dyno tested and again see if the figures are in line with the VE for the increased displacent.

I would say one thing though - if youre running the stock 986s tune in this motor, that means you have the oem MAF housing in place, and presumably the rest of the intake is stock as well. On a 3.6l block, I'm sure you're losing power there. Upgrade your intake and do a 996 tune.

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[barkinfool]

Thank you for your insights Ike!