Remapping ECU
 

Watching wheeler dealer this am. Ed remapped the Ecu on a 944 turbo gaining about 30hp. Can this be done on a 3.2? Pros/cons?
Just curious, thanks.

Key is that it was done on a turbo engine. I gained 40+hp on my tuned Audi but that's because in the tune, they reprogram the engine to supply double the boost. With a N/A engine, you can't do that. Yes, if they optimize the tune, you can maybe get a couple extra horses, but nothing near 30hp.

Ah, thanks.

Easy to do on Turbo engines as you are upping the boost supplying much more air to the engine. Your engine's air supply is fixed unless you make some hardware changes. You can optimize fuel delivery and timing because manufacturers have to be somewhat conservative with it because it has to run right in all weather conditions at all elevations etc.. and it has to be smooth and reliable and compensate for you occasionally getting poor quality fuel and so on and so forth.
You can gain a few hp from remapping with more aggressive timing curves but it won't be all that much, probably 10-15hp peak with maybe a nicer midrange torque curve. Oh and be careful of tuner's ads for hp gained with their tunes. Back in the 90s I worked in a performance shop and ran a flowbench and dyno and we made some aftermarket parts for Mustang 5.0s. A lot of the chips we tested that gained 25hp advertised only did so at unusable rpm long after you shifted, peak hp would be like 3 or 4hp gain. Some of them would get down right scary lean conditions.

Thanks, this is very helpful. So is weight reduction really the only way to increase lbs/hp with a NA 6 cylinder other than going bigger motor? I'm not quite sure air filters and different mufflers work though I don't know.
I guess I could search. Thanks.

Weight, Undersized pulley, free-er flowing exhaust will help. The under-drive pulley being an immediate HP pickup. We eliminated the 2nd set of cats on your car along with the original muffler. A LOT of unexpected weight lost there!!

An upgrade to a bigger engine is always possible but spendy :-)

The most expensive option is to use a "Tune" that causes you to fail Smog Test for an equipment tampering violation.
Before you buy, get a written promise that the Tune will pass Smog Tests in your State. The new Smog machines can detect ECU program changes. And in California, the old Pre-Test trick no longer works either.
The work around is to makes sure it is easy to revert to the OEM settings and do it a month before the Test to make sure the switch is undetectable and that you have no Pending Codes.If you doubt the significance of the "Equipment Tampering" violation punishments ,I suggest you Google it. Recently the costs for re-complying have escalated.

One of the most common, and least appreciated, effects is the inability of a reflashed car to pass modern "advanced" smog testing (read connect with the OBD II system and read) now required in many states. We have had cars ranging from 986 Boxsters to 996 Turbos that failed these tests after getting the DME "flashed", and the only way to get them through was to take the DME back to stock programming. This used to only happen once in awhile, but is now cropping up more often, apparently as the state systems get better at noticing something is different.

FWIW, I recently passed the NJ state inspection in my APR tuned Audi. I had the ability to switch back to stock programming very easily, but kept it in tuned mode, and it still passed without any issue.

Tell you what the most unappreciated mod is, lightweight set of wheels. You want your car to accelerate, stop and corner better then save a few pounds a corner. The rotational weight of a wheel is so much more than just regular weight. I had a friend who did circle track and went from a 19lbs wheel to a 16lbs wheel and caught right up to the front runners. Couldn't believe the difference with just that. I just sold a set of 3 piece BBS wheels, in 16x7 they were only 15.4lbs a piece, your typical factory wheel in that size is in the 24-28lbs range. The fact that it is unsprung weight and rotational weight makes the biggest difference. Imagine you tie a string to your finger and spin it around in the air with a 25lb weight on it at 70mph and then reduce that to around 19lbs and you will know why it makes such a difference. Beauty of going with lightweight wheels is that they look great and you don't sacrifice any driveability or comfort creatures to do it. Having said all that some factory wheels are not heavy. I am putting a set of Cayman wheels on mine and the 18x8 front is 21lbs and the rears are 22.8 according to my luggage scale.

Problem is 16" wheels don't look good no matter how light they are. :D 18" OZ Allegererita HLTs are only 17.4 lbs front / 18.8 rears, and look pretty decent.

I wasn't implying to go 16s just citing how light they were, going with lightweight in whatever size you chose is the recommendation I was implying. Yours sound really light and I have had OZ wheels before and they held up decent albeit not great on Michigan roads (I bent them in a couple seasons)

Oh I know you weren't suggesting we go to 16s. :) You make a good point. It's an easy way to gain performance. I don't have the OZs right now (have SSR 3-piece forged wheels currently), but even those aren't that light (24lbs)...will be switching to those OZs if I ever need to replace the SSRs.

LOL, you know we're picky when we know the exact weight of our wheels. Just another reminder of how important rotating weight is, why do you think the high end cars have cross drilled brake rotors, the answer of course is to save a few ounces of rotating weight as they are really just prone to cracking that way but rotating weight is that important.

Cross drilling is for heat dissipation. Allows air to circulate through the inside of the rotor.

Anker

Depends how big he makes the holes ! :-)

Thanks for chiming in JFP. I hate to see people get in legal & financial trouble with the Authorities when they were just enjoying their car hobby.
We have the new "DAD" machines in Calif and they are very effective at detecting any changes to the ECU. I have an interest in a repair facility that uses this equipment.The DAD compares the tested car's ECU to a 'map' of the stock ECU values. They give a report of all the differences. The DAD equipment automatically Flags 'tunes' and issues a Fail. The FAIL Report requires the owner to go to a Referee. Silly name. It really means instrument of unlimited financial torture and legal misery.
These DAD machines are gradually becoming the standard in other States. There is some uncertainty about how far back in time their ECU map knowledge goes and if they are extending it .The resources deployed to catch a few Tuners is alarming.
We recently had this discussion elsewhere and I linked DAD Training videos to indicate how effective their detection system is. I like 'tunes' and have used them but this DAD system is a game changer.No Tunes for me anymore. I abandoned posting when people with tunes insisted they could get around the test - but hadn't bothered to study the DAD materials. Now the weeping tales of misery with the Referee are beginning to creep into some car tuning Forums. The worst scenario is that you get a new Smog Test to sell a car. After the test you reflash the ecu to impress a potential buyer with the performance of the car. Later the new owner fails a Smog Test due to ecu tampering. It gets nasty real fast .

Don't buy into that myth, it does not. Read up on it or go the track with your infrared thermometer. It is just for weight reduction because they had to make the rotor larger and thicker.

Both are incorrect; the rotors are cross drilled to allow gases to escape from between the pad and rotors. In dry conditions, the primary gas generation is from the bonding agents that hold the pad together. In the wet, steam is added from the heat. In either case, gas generation between the pad face and the rotor tends to push the pad off the rotor, with a significant loss of breaking effort. Give the gas somewhere to go, and the problem goes away.

I did some more research and I believe this page is the closest. According to the cross drilling and slotting improve both cooling and pad contact.

Anker

For an undersized pulley, do you need another size belt? I am guessing we are talking a pulley that run the water pump, alternator, etc. How does that work?
Why would porsche not have done that?

Is it a DIY for a novice?

Does the undersize pulley give an improvement you can actually feel?

Yes, Yes & Yes...
Yes you need a different length belt - usually from the underdrive pulley supplier.

Yes a novice can do it if you have a new bolt, Loctite and a good torque wrench.

Yes you can feel the difference but only at low to medium engine speeds. They say about 5 HP max.

Two points of reference: A) don't buy a cheap pulley with large "open" section & thin arms - they break, and B) you lose the engine TDC timing hole drilled in the original solid pulley.

It's not, you are citing someone trying to sell you a product, try searching engineering pages. I can just about see the Brembo building from my house and have met plenty of engineers that work there and got plenty of info on this, they do not help cooling period. Slots help gasses escape although holes can too but it has nothing to do with cooling, 100% there for weight reduction on large rotors. If anything the holes create less braking but the weight offset is worth the miniscule reduction in surface area.
Ok, I'm done going off topic in this thread.

5hp, I'll pass on that idea. Doesn't seem worth the trouble. Thanks for the info.

They do. The latest GT3's have undersized pulley.

5hp for 200$ is a bargain on a naturally aspirated engine (and especially a Porsche), don't expect anything cheaper than 100$ per gained HP!

Before remapping, you'd better modify other stuff or the remap will just be a waste of money.

At the end of the day, don't expect your 3.2 to gain more than 30hp without throwing a lot of money at it (plenum+TB, exhaust, camshafts, airbox, and remap).
And of course, no more passing emission testings.

Most of the Kits come with the correctly sized belt.

By far the cheapest easiest 5 HP your going to get on this car

It was the loss of tdc on the pulley that I was worried about. How is that handled when one needs tdc for a later project?

You keep your old pulley and don't grind the boss completely.
You don't need the lock the engine at TDC every day ;)

Does the underdrive noticeably lower the output of the alternator, affect the coolness of the A/C, or water pump effeciency? Is there no downside? If not, why wouldn't factory just install an underdrive to gain a free 5hp?

I'm even seeing some not advocating the install of these things...

https://www.powerbastards.com/articles/underdrive_crank_pulley.asp

alternator output isn't really a concern on a Boxster. If the alternator spins slower, the regulator will adjust and the output will stay the same. Only the maximum output will be affected.
The link you're posting is from a High-Output Alternator manufacturer, for guys who maxed out their stock alternator because of their big sounds system and 12 lights and 3 light bars. ;)

The A/C system is regulated by the Thermal Expension Valve, if it's correctly charged and in good condition (no or very little moisture in the system), you shouldn't have problems.

Same for the water pump, the flow isn't regulated by the pump but by the thermostat.
A wp and thermostat in good condition should be able to do the job without problem.
On the other hand, an underdrive pulley will reduce the risks of cavitation, which can be big problem with metal impellers and will dramatically reduce the pump's efficiency.

It will also reduce the common overheating problem of the power steering pump.

Why isn't it factory? Same reason why the engine doesn't make 300hp from factory, same reason why they chose to use a sealed bearing to support the IMS. Engineers aren't perfect, they have to compromise. If they loose 5hp but can increase the life of the alternator regulator beyond the point of factory warranty, they will.

And as I said, 991 gt3's do have an underdrive pulley from factory. And the 911r a single mass flywheel. Things that you don't find on regular 991's.

Thanks, so basically, the tradeoff for a little more power is possible alternator/regulator longevity (I read somewhere that in order to compensate, the alternator will operate at more torque), but possibly save other accessories if car is tracked. I can see how it could be a good tradeoff if you want to squeeze the most out of it like the factory GT3 does as you point out. How bout their claims that the car's ECU will detect the deficiency and accordingly dial back the power output?

In my case after installing the UDP, I noticed that the water temp would start to rise a little faster if I was stuck in traffic, presumably due to the water pump turning a little more slowly? However it was not a big deal and when the high speed fans kick on it stabilizes. I could definitely feel more of a kick in the pants in 1st and 2nd gear after installing it. I also did it to reduce load/heat on the power steering pump which is known to fail due to heat during sustained hard driving on the track. Although I never had any trouble with that before I installed the UDP.

I can def see advantages to doing this if you're tracking the car.

It is true that newer cars don't like seeing low tension.
But the Boxster being a small car without a lot of accessories and electronics, it will be perfectly fine with its stock alternator, even with an under drive pulley.

If I don't sell my car, it's my next move!