Can you all help a new guy out with an exhaust question?

[IanW505]

Hey guys,

I've been researching this alot and reading a bunch of old threads, but i still have some questions. I'm looking to install a new muffler/cat bypass system on my '84 targa (probably from Fabspeed, since they're more or less down the street from me). I was planning on just doing the muffler and bypass pipe, but a Porsche mechanic i was talking to says that i need a chip too. He explained that the stock mufflers and such are set up to provide a certain amount of backpressure, without which the engine doesn't run at optimum performance. Does that sound right?

From what i've read in previous posts, it seemed like alot of people here have an upgraded exhaust system, but no chip. A fabspeed chip isn't too expensive, but if i don't need it, then i'd rather spend the money on something more useful. Any suggestions or feedback you guys have are greatly appreciated. I'm very new to the technical aspects of Porsche's and value your opinions alot. Thanks in advance for your replies!

-Ian

[don911]

I think the stock chip will work fine with the bypass pipe and sport muffler. I think people replace the chip to eak out a small amount of HP/torque. Also, the stock muffler will be fine as well with the by pass pipe. Unless you want a more aggresive sound, the stock muffler is pretty good.

[MXMARK]

Ian, I have a cat-bypass and Steve W chip. I ran the chip with out the cat-bypass and with the cat-bypass. Both seemed to improve idle,drivability and all around performance. With the cat-bypass I gained a wider powerband with even more drivability and it runs up to red line much faster and is very very smooth. Next will be a sport muffler maybe Dansk 84mm. I am under the understanding that the stock chip can make up for some of the exhaust upgrades but you may want to richen up the entire RPM range. With the emissions retraints that were put on the stock chip you will be running alittle leaner then you may want, I think?. I have raced Motorcycles for years and there has been no such thing as a performance pipe with stock jetting. Again this is EFI and it should be able to compensate for some upgrades.... Try the Steve Wong chip from www.911chips.com or through our host. If you don't like it Steve will refund your money. Very happy with my 1985 with this chip. I hope this helps. Thank you for reading Mark

[IanW505]

good to know, thanks for the input. I definitely want to buy the bypass and muffler, i just wasn't sure if i needed a chip or how much it would help. I think i'm just gonna go for it, it's not a whole bunch more. Can chips be reprogrammed too, like if i ever want to upgrade something else that requires a new chip? or do i just have to buy a brand new one? Thanks again, i'm pretty much in the middle of a crash course in figuring this stuff out.

-ian

by the way, what's a side shift? sounds kinda cool

[MXMARK]

Ian, I have an 1972 914 that came with a tailshift set up (like early 901 really sloppy). I bought another car 1974 and took the side shift trans and linkage out to sharpen up the shifting. What would be nice would be a Wevco 915 stetup with a 3.2l-6 in my 914 but that will have to wait. Steve W is able to reprogram his chips so fabspeed should be able to also. I make no claims of knowing alot about EFI if any. Just what I have read and experienced. Have fun with your new toys Mark

[IanW505]

so it seems like most of the HP gains is out of the chip and bypass pipe, not nescessarily the muffler. If that's the case, then maybe i should just skip the muffler and do the chip and cat bypass. Can anyone comment on the sound change as well with this? i don't want it to be obnoxiously loud, but a deepier/throatier sound would be an added plus.

Again, any comments or suggestions are appreciated,

-Ian

[MXMARK]

Ian, Mine sounds a little louder at idle not much. Not bad. The rest of the range sounds stock. There is a mod that can be done to the stock Muffler I just don't have the details but I did see it here on the BB. I still want the 84mm Dansk sport. Mark

[Jeff Alton]

Ian, I have an 84 with the Fabspeed pre-muff, sport muffler and a SteveW chip. It seems much stronger than stock and not too loud either.

Jeff