NineMeister

Just had the Cup car on the dyno. With a standard Cup chip the car previously made around 300-303hp on our dyno. With the headers and silencers fitted we have just recorded two pulls of 311 and 313hp, showing similar 10hp gains everywhere with the best increase at 3500rpm where the headers made 360Nm against the stock exhaust with 326Nm. Just getting into the swing of things when we ran out of fuel, so it's off to the pumps for some fresh Shell V-Power and back on the dyno in the morning. In fact thinking about it, the fuel in the car has been in it since the March RS trackday, so I'll be expecting even better results with a fresh fill up of 98RON.

NineMeister

The 993 style cross-over system was adopted from the outset so that you could run bypass pipes or cats as desired/required. My expectation is to simply sell the headers with cross-over bypasses for either the 964 or 993 and to offer 100 or 200 cell cats as an option. As for restriction, I think you will be surprised, I ran cats on my 3.8 & 4.0 litre race engines for some time and did not have a problem, although in the end they failed mechanically from the usual vibration/knock damage and had to be removed.

There is a possibility that we may test a few different silencer internals so that we can offer two noise levels, a super quiet with 98dBa at 0.5m and a normal at 102dBa, which would correspond to the typical UK trackday quiet & noisy days. It would not take much to produce a pair of silencer "G-pipe" style bypasses to run with the cats, so I guess the answer is that if that is what you need we will make it for you. It would certainly make fitting it under the back of the car a lot easier!

dbf73

I suppose the next step is to have a variable (by the driver or by rev level) on the fly version. On a more realistic note .I thought the 964 and 993 had different flange styles where the headers mount to the head or do you actually have 2 separate model header for the 2 cars? or am I all wet?

warmfuzzies

Everytime Colin posts something on here, I sit back and think of Robert Linton....

Bloody nice, but hell I've got no chance of ever being able to afford/lay my hands on that kind of kit...

It's almost like showing the kids sweets through the school gates....then running off down't street.....

ahh well.

Kevin

Strega(UK)

£4000!! Now I know I'm in the wrong game!! Why didn't they teach pipe bending in school??!!

ste993

NICE!

Tom W

I can see the desire to do something like this for a street/race car that has to pass inspections for use on the street. I can't see the benefit on a track only car where good headers with simple mufflers will work just fine - it's a lot of money for an exhaust package. How much of the cost is due to having a cat (which is only needed for a street car)?

NineMeister

Tom,
In the UK we have to run heavily silenced cars on track, the maximum noise level we are allowed (with few exceptions) is 105dBa measured at 0.5m from the tailpipe, although there are some tracks that have a 98dBa limit for certain days. To put this in perspective, a stock 993 with totally stock cats and silencers may just scrape into the 98dBa level, whereas a stock 964 will be around 100dBa. Your typical 964 with cat bypass measures 102-103 and a 964 with the favoured cat bypass and cup pipe is up at 105-106.

When I first started the 993/964 engine development I wanted to buy a complete cat-free system that would allow the engine to achieve its full potential and still be well within the 105dBa limit and prefereably be down at 100-102 to allow for inaccurate sound measuring equipment at some tracks. The bottom line is that I could not buy a system for my 993 (or a customer's 964) that would achieve both objectives. For the 964 I bought some nice long tube headers and then had to make our own 3 silencer system to get it close to the noise limit, it was a nightmare to make and in all honesty had resonance problems at low rpm, but it just about did the job. For my 993 the cheapest full package I could get, without cats, was around £5k. The result is what you see now.
As mentioned in my reply on the 993 forum, these headers are currently costing around £4k to make, so I have taken the risk of advertising this price in the hope that we can reduce manufacturing costs soon and hence make Colin a small profit. This price does not include cats.

For the 993 platform I can sell just the headers and a pair of crossovers to run with stock, modified stock or aftermarket silencers. The current price for just the headers and crossovers would be around £2400. For the 964 platform you will need custom silencers, brackets and crossovers, together with a fitting kit and modified oil pipe; this is what bumps the price up to £4000.

As for benefit - on a recent sprint at the new Anglesey circuit, my 993RS with the prototype system fitted measured 101dBa on test and went on to beat a brand new 997GT3 driven by an ex-British hillclimb Champion by 4 seconds on a single lap. We were both new to the circuit, and at the end of the day I posted one run of 94.37 seconds against his best of 98.14.

N51

Colin,

Outstanding work! I'm all for performance without noise. My desire for opera and performance. I know you've not calculated that in your design. :-)

Best,

NineMeister

You can't fit a 993 header to a 964, but you can fit a 964 header to a 993 if you move rhs exhaust studs to the alternative holes in the heads, so the full answer is that we have "made a 993 header with 964 stud pattern that hence fits both cars". Thanks for pointing this one out.

chancecasey

I am willing to go to all the trouble to test these on a 964 race car at Infineon and Laguna Seca for you.

Tom W

Colin,
Thanks for taking the time to explain further. It does appear that in the case of very tight sound limits, where maximum performance is desired, your system fits the bill. (pun intended, and meant in jest)

Part of the difficulty in interpreting the benefit of your system is the different ways the sound can be measured. Many tracks out here (Northern CA) allow 103 db - when measured from about 20 feet away - so most any exhaust with minimal mufflers will pass. On my car, running headers with dual Phase 9 mufflers runs about 97 db. My car also has MoTeC and the engine dyno said 300 hp (I'm limited by class rules on the induction system).

The problem track is Laguna Seca where 92 db is the typical limit. The sound station there is about 20 feet off the track too (on the uphill straight between turns 5 and 6 where you are normally at WOT) but they also use portable units to catch people who lift or otherwise try to beat the fixed station. A 964 with cat bypass and secondary bypass (but stock primary) runs about 89 db there (my old exhaust). I now switch the Phase 9 mufflers off and add an old "banana" style 911 muffler to meet sound at Laguna Seca (but pay the penalty in hp the swap costs).

It appears you system gets the sound down to about what would pass at Laguna Seca, but does not cause the performance hit. Yes?

Robert Linton

Kevin:

The good news is that if we did this it might be even more expensive.

Full Boost

Robert,

ROFLMAO!

Simon.

Christer

£4000.............