964 RS Tuning - Page 1 - Porsche General - PistonHeads UK

Standard 964RS usually meets 260bhp factory level, but fails to break 270bhp. Never tested the bits seperately, but the usual & inexpensive chip/airbox/K&N/cup pipe/cat bypass set up will make 285-290bhp for less than £1000 fitted, so why p*** about, just fit the lot. The only two mass flow kits I have tested made 297 & 298bhp on a '89 964 and a 92 RS, both with no cat & cup pipes. The Motec options are listed elsewhere on the forum.

I fitted the Cup bypass first as it was a nice secondhand buy. This made a nice noise but also boosted midrange substantially. The Cup airbox (equates to drilling holes in the airbox) had a mixed effect - very slight increase in top end with a consequent dip somewhere around 4k. So if you were picking and choosing I'd go with the Cup pipe first.

Many thanks for the reply. In answer to why P*** about.Two things spring to mind, firstly if I know what gives what changes, I can make an informed decision on what not to fit. For example if I fitted both a cup pipe and air filter and it makes 270 logically the chip and cat bypass would make up the extra 10 but cost say an extra £500 so 10 horses for £175 or 10 for £500, all figures arbitary as I dont know. Secondary point is noise, with track day noise tests becoming an issue it would be nice to pick my way through the quietest options if possible. Hope you see what I am getting at. I agree, to some £1000 is not lot of money and they can throw it all in one direction. But I could put my £500 saved to setting the car's geometry up and live without the extra 10hp and have possibly the faster car at the end of the day!

With regards to noise. My 964RS has a cup bypass, K&N, Drilled Airbox and I've removed the undertray and have fitted a bigger exhaust tailpipe. This gives out about 101-102db using the 0.5 metre test at approx 4K revs. I can JUST get into Bedford with their 101db limit. The car is also chipped and has a larger thottle body. It's not been dyno'ed but is quite a bit quicker than a standard 964RS. >> Edited by paulc on Wednesday 27th November 14:27

For noise implications, fit either the cup pipe or the cat bypass but not both for normal days, although you will never get it out at Goodwood or Donnington when they are having a quiet session. At Oulton, donnington & Silverstone on the usual test days the cat & cup pipe will be ok. The chip with a K&N will make 275bhp. Do the wheel alignment first, as otherwise you will just get yourself into more trouble quicker with additional power.

Actually I'd disasgree with you Colin (shock, horror)! Whilst Goodwood is a no-no as far as noise is concerned, the Donington track controllers seem to be a lot less discriminating when it comes to noise unless your car is *really* bad. Rather than meter every car that goes out, they meter at the pit wall when driving by and only pull and test things which seem too loud at that point. The wise driver will short-shift on the pit straight...

What "chip " would you recomend for the RS

I suppose this question is mainly aimed at Colin (Ninemeister) though I guess others can chime in. I am interested in what effect the following have on HP and driveability when applied to the RS engine either on their own and or as part of a package(loose term): Holed air box K&N De-cat(bypass pipe) cup bypass (center pipe) G-pipe small G-pipe long Chip also wondered what most RS engines dyno at before work do they make factory figures! Hope I am not asking you to give away any trade secrets. Just would be nice to hear from someone who is likely to have genuine data.