Tuning a 2.5l Boxster?
 

Hello, although I have only just got a boxster and am happy with the performance it is part of my hobby to modify every car have ever owned. So you may be getting some bits of info from me as I plan to experiment with my car. With my last car I managed to squeeze an extra 50bhp from a 220bhp engine. Wasn't a porsche though!.

Anyway what engine modifications if any have you guys carried out? Engine managment chip change. New Air cone filter(K&N) or any exhausts which may make a difference? The car I have is 205bhp 2.5 boxster. The torque is the same as my previous car so doesn't feel like it accelerates slower but would be nice to know I have good bhp.

Well I have the 2.7 so my base hp is slightly higher then the 2.5 was, but as far as modifications I beleive the both the 2.5 and 2.7 benefit from many of the same type of modifications.

As far as tweeks to make the car faster:

1) Fuel chip tuned on a Dyno can add about 25-30 hp. This process requires a chip to be removed from your Cars ECU and then flashed based on the stats that come from a Dyno test of your specific car. This must be done by someone who truly knows what they are doing.

2)AirBox. You can gain about 7-9 hp. There are a few kinds of airboxs available for the Boxster. I ended up ordering mine through TTP in Germany which makes many modifcations which I have done as well from them. This item give a nice sound!

3) Iridium Spark Plugs. THis is a simply tweak some guys and I came up with to replace the Bosche Plugs that are standard in the vehicle. If you decide to do this option I would suggest doing it prior to having your Fuel chip tuned. You could possibly end up with Air/Fuel mixture rations going bonkers.

4) Custom Headerby TTP. This mod completely removes the two front Cat Converters due to the new heads being extra long. This is a great mod! Probably 5-10 hp depending on who you buy yur pipes from. Craftmenship means alot in this area. FYI removing teh front to Cats is how the Euro version of the Boxster is.

5) Replace the two rear stock cats with a High Flow Cat. This will only provide maybe 2-3 more hp but allows your engine to breath a lot better. A must if you do both the headers and muffler.

6) replace he stock muffler. you wont get a huge gain here, maybe 5-7 hp, but can truly change the sound of the too quiet Boxster and make your 986 sound more like a 996.

7)And lastly something I have been working on with some local engineers with TTP is putting a twin turbos on the car. Through some feedback from engineers at TTP if done properly can add about 100 hp to your vehicle. I hope to do this mod maybe this fall. Its an 80 hour job.

Hope some of this info helps :)

Are your hp improvement numbers actual dyno results? They just seem a little bloated.

According to my last Dyno from having my exhaust system installed, my Boxster rated 291 hp..
The end result of HP is based on several things. First off the quality of the parts you buy, the engineer tweaking your air/fuel mixtures, and whether you have a 2.5, 2.7, 3.2 or anything else.
The stats on the Twin Turbo are real too. I havent had this installed but have seen the Dyno results from the turbos on a 2.5 which TTP did in Europe this last fall.

Yeah I believe the turbo numbers without a doubt. With enough money you could build a turbo setup to more than double the amount of power any motor puts out. I'm sure you knew that though.

Very True.
Actually the Turbo numbers I mentioned are based on 12 lbs turbos on the 2.5 and is also strictly bolt on. I heard a 14 lbs version is going to be available soon. I have heard with additional work to the engine at the same time boring out the engine, replacing seal on some other stuff you can add another 20-30 hp on top of that. But I also hear the additional work is about another $5,000 on top of having the turbos retrofitted onto the engine.

Dont get bored....
 

"I have heard with additional work to the engine at the same time boring out the engine, replacing seal on some other stuff you can add another 20-30 hp on top of that. But I also hear the additional work is about another $5,000 on top of having the turbos retrofitted onto the engine."

Just a side note: the boxster engine has Lokasil lined cylinder walls which CANNOT be bored out. The block is slip-cast with two types of aluminum: one which maximizes the block's torsional resistance and one which maximizes the wear properties of the cylinder walls. Therefore you cannot simply widden the cylinders....look it up.

Lots of different ideas on this. I looked into engine mods a few years ago as I used to hot rod a lot of Fords, Chevys, Hondas, and Nissans. With very few exceptions I found engine mods on a 2.5L to be just a big black hole for Benjamins. Very little performance return/dollar spent.

FWIW every Boxster class track record on the West Coast was done in a car with a stock motor. No turbos, no chips, no plenums, no nothin. They did their mods on suspension, weight loss and tires. This is where I am doing my R&D.

Ultimately it is your car and your dough. Do whatever you think will make your car what you want it to be.

The best and only good mod, for the 2.5 IMO is an under pulley W/ harmonic dampener cheap and easy DIY and a 10hp. Gain for about $ 175.00

If that is not enough buy another Boxster W/ a larger motor.

Incorrect.
We have had extremely positive results with taking the stock 85.5mm 2.5 bore size and boring that to an 89mm using the technology we co-developed with LN Engineering.

We just finished a big bore 2.5 that made just over 200 RWHP with stock intake, stock exhaust and no ECU tuning at all.

The 2.5 is the first engine we began development of and the technology to perform a big bore solution for this engine is the oldest and most proven of all our developments. 89mm is the largest we can go with the technology, which produces a 2.7 when coupled to the stock 2.5 crank and 2.9 liters when coupled to the 78mm crank found in the 2.7. The 2.7 uses the same factory bore as the 2.5 @ 85.5mm, its basically a "stroker" 2.5 engine.

All that said, I have found that the 2.5 engine is the best developed from the factory as far as power is concerned, the UD pulley is about the only real power maker I have seen to date.

I refuse to compromise anything for performance, so I am not big on ECU tuning, exhaust implementation and etc. My direct experience with all of these has generally been a compromise of some other important aspect associated with drive-ability.