George's headers vs. Bursch

[ninesixfour]

After a multi-hour search I think I've got an idea on the pros and cons of George Narbel's European racing headers vs. Bursch but would appreciate any owners that could set the record straight.

1. No O2 sensor bung on the Bursch but what about George's? Can he add one if the customer requests?
2. Both are mild steel so will rust. Ceramic coating helps delay this but won't prevent it completely. There are several stainless options such as SSI, GHL, and B&B.
3. Oil lines have to be changed for the Bursch but I saw at least 2 pictures of George's with the standard oil lines in place on an SC or 3.2.
4. Access to the valve covers can be tight with the Bursch and they may not be removable without modifying the covers or studs. I didn't find any info on this for George's.
5. Several people mentioned their Bursch headers cracking and having to be replaced, sometimes at Bursch's expense. Never heard of a set of George's failing in any way.

Are the power gains similar between the 2?
As far as sizes go, 1 3/4 for a 3.2 race car, 1 1/2 for a 3.0.

Any more info people could provide is much appreciated.

[TimT]

George

modify to suit.....inre O2 bung etc

[David 23]

I have been researching headers for a racing SC also. In addition to George's and Bursch, there are others to consider: Fabspeed, s-car-go, OBX, etc. It has been confusing to say the least, and I certainly don't have the answers.

[Steve@Rennsport]

We've had FAR better luck with George's over the Bursch ones, hands down.

One day soon, I'll try the OCX ones on the dyno and see how they measure up.

[ninesixfour]

Originally Posted by Steve @ Rennsport Systems

We've had FAR better luck with George's over the Bursch ones, hands down.

One day soon, I'll try the OCX ones on the dyno and see how they measure up.

Far better luck in terms of power, build quality/longevity, or all of the above? Do you have to reroute the oil lines for George's? Do they require adapters to use the M&K race mufflers or megaphones? What about the clearance issue near the valve covers?
I looked at the OBX site but didn't see Porsche listed. As far as Fabspeed, S Car Go, and others, if I'm going to spend the $$ on stainless it will be SSIs. As far as I can tell from my research they make the same power as the pure racing headers, the only downside being more weight due to having heat.

[mb911]

Originally Posted by ninesixfour

Far better luck in terms of power, build quality/longevity, or all of the above? Do you have to reroute the oil lines for George's? Do they require adapters to use the M&K race mufflers or megaphones? What about the clearance issue near the valve covers?
I looked at the OBX site but didn't see Porsche listed. As far as Fabspeed, S Car Go, and others, if I'm going to spend the $$ on stainless it will be SSIs. As far as I can tell from my research they make the same power as the pure racing headers, the only downside being more weight due to having heat.

I suggest street adapters then our track mufflers as it pushes the exhaust out back of the car rather then underneath

[David 23]

Originally Posted by Steve @ Rennsport Systems

We've had FAR better luck with George's over the Bursch ones, hands down.

One day soon, I'll try the OCX ones on the dyno and see how they measure up.

I'm also interested in what areas you had better luck with ERH. From looking at the two systems, I would have guessed the Bursch would perform better due to the merge type collector rather than the way the ERH tubes join together. OBX look like a copy of ERH, I think it would be VERY interesting to put them on a dyno compared to George's and Bursch systems. The more expensive stainless headers like Fabspeed, s-car-go, etc. make a point about being equal length tubes, are Bursch, ERH, and OBX equal length? Does anyone have any dyno data comparing these systems to the less expensive alternatives?

The discussion related to this would be what to do AFTER the headers. For racing is straight pipes with no muffler better, or will some type of muffler actually increase power?

It seems to me there is a lot of subjective opinion in this area that could be sorted out with some dyno work.

[beamonk]

Where does one find information on George's headers? Is there a power increase going to headers on a stock 993 SC conversion?

[Steve@Rennsport]

Originally Posted by David 23

I'm also interested in what areas you had better luck with ERH. From looking at the two systems, I would have guessed the Bursch would perform better due to the merge type collector rather than the way the ERH tubes join together. OBX look like a copy of ERH, I think it would be VERY interesting to put them on a dyno compared to George's and Bursch systems. The more expensive stainless headers like Fabspeed, s-car-go, etc. make a point about being equal length tubes, are Bursch, ERH, and OBX equal length? Does anyone have any dyno data comparing these systems to the less expensive alternatives?

The discussion related to this would be what to do AFTER the headers. For racing is straight pipes with no muffler better, or will some type of muffler actually increase power?

It seems to me there is a lot of subjective opinion in this area that could be sorted out with some dyno work.

We've done a lot of dyno work on these engines since 1976 so its not really subjective,... That device doesn't lie but one needs to understand the data and how it applies to each set of circumstances and objectives.

First, Bursch headers have no merge collector; its not even close to one.

Second, 911 engines are not as picky about collector configuration until you are operating at very high RPM and looking for that very last 3-4 HP.

Third, Header lengths ARE very important as are diameters and both are chosen based on engine size, camshaft profile, compression ratio, and head configuration. Equal length primaries become increasingly important as camshafts become more aggressive. With OEM smog cams that have little or no overlap, its not very critical.

Lastly, 911 engines ARE very sensitive about secondary lengths and the effects of a crossover, whether its additional plumbing or a common, dual-inlet muffler. One measures distinct torque increases right where you need them with such designs. Open megaphones w/o a crossover makes a narrow power & torque range requiring rather close-ratio gears to be practical.

Exhaust designs make a noticable differences in the quantity and spread of both HP and torque. One needs to be very careful when choosing such systems to prevent compromising a useful torque range that doesn't match the car's gearing.

Hope this helps,

[David 23]

Steve,
Thanks for chiming in, your input is always helpful. I didn't mean to imply subjective as a criticisum, it is just that I have never found information that directly says X system gives _ result; Y system gives _ result, etc. So it is hard to determine practical solutions when faced with all the choices. I suppose the reason I haven't seen clear data is that there are so many variables it becomes difficult to document. I'd love to hear more specifics about what your dyno testing has shown over the years.

The design and effect of crossovers is very confusing to me, and it is hard to know what configuration helps or hinders Hp and torque. Can you shed a little light in this area?

I have not seen many complete systems designed for a stock class engine racing application, other than the Pete Webber phase 9/10 system and the one on your website. Is there something else you would suggest? Would you consider the ERH system that includes the small muffler on each header outlet then each side bending around to join at a single central outlet, a crossover type system? Can you comment on this design, as well as the one you have on your website?

I realize this discussion would probably be easier over the phone or in person, but it seems to be a topic that applies to a lot of people, and perhaps trying to address it here is ultimately of greater benefit.

[EarlySport]

Subscribed

[Steve@Rennsport]

Originally Posted by David 23

Steve,
Thanks for chiming in, your input is always helpful. I didn't mean to imply subjective as a criticisum, it is just that I have never found information that directly says X system gives _ result; Y system gives _ result, etc. So it is hard to determine practical solutions when faced with all the choices. I suppose the reason I haven't seen clear data is that there are so many variables it becomes difficult to document. I'd love to hear more specifics about what your dyno testing has shown over the years.

Hi David:

No worries, mate. I merely wanted to be emphatic that while there certainly are various opinions, extensive dyno testing has been done for many years by principals in this business,..

Given the massive investment in equipment and time, most of the data is not in the public domain for competitive reasons. Most shops who own engine dynos endeavor to assist their clientel to be as competitive as possible so a lot of test result become proprietary since the customer ultimately underwrites this kind of research,..

The design and effect of crossovers is very confusing to me, and it is hard to know what configuration helps or hinders HP and torque. Can you shed a little light in this area?

This is a very complex subject but I can tell you there is no downside nor liability for using a crossover (balance) pipe in a race exhaust system except where peak HP is the main criteria and very close-ratio gearing is used. The GT-3RSR is one example, another would be an F1 car. Crossovers (both H & X-types) as well as dual-inlet mufflers permit better cylinder scavenging in the mid-range as both side of the system pressures and acoustics are allowed to affect both sides of the engine. This applies to all 6 & 8 cylinder engines.

I have not seen many complete systems designed for a stock class engine racing application, other than the Pete Webber phase 9/10 system and the one on your website. Is there something else you would suggest? Would you consider the ERH system that includes the small muffler on each header outlet then each side bending around to join at a single central outlet, a crossover type system? Can you comment on this design, as well as the one you have on your website?

I've not used nor tested Phase 9's as these are too loud for our local tracks but we have tested several race-type dual-in/dual-out mufflers such as the Flowmaster Series 80 and they work VERY well if coupled to the right headers for the engine and plumbed correctly. The system pictured on our website is no longer in production due to noise constraints but it worked really well so I left that image up there for people to ponder. Its VERY enlightening if one stares at it for awhile and carefully observes the details.

I realize this discussion would probably be easier over the phone or in person, but it seems to be a topic that applies to a lot of people, and perhaps trying to address it here is ultimately of greater benefit.

You are right about that as it does apply to many people looking to improve the performance of their 911. I wish I could offer more specifics but I'd be fighting off some angry customers who rely on us for that "unfair advantage".

[David 23]

Steve,
You have been very helpful, and presented some interesting points and clarification.

I totally understand and respect your position and relationship to your clients, and certainly don't want to put you in an uncomfortable position, just trying to learn as much as I can. I'll try to keep the questions in general terms.

Thanks.

[Steve@Rennsport]

Originally Posted by David 23

Steve,
You have been very helpful, and presented some interesting points and clarification.

I totally understand and respect your position and relationship to your clients, and certainly don't want to put you in an uncomfortable position, just trying to learn as much as I can. I'll try to keep the questions in general terms.

Thanks.

I hope so,...

There is a lot of really good information in the Hot Rod world that applies nicely to the 911 on this subject. Do some "Googling" on exhaust crossovers as well as search the archives at Hot Rod and Popular Hot Rodding magazines. These guys as well as NASCAR's Sprint Cup engine builders are far ahead of us in this (and other) regards.

[ninesixfour]

Thanks for the info Steve. The exhaust pictured on your site is indeed an interesting design. It looks like the intention is to not completely eliminate back pressure I assume to enhance cylinder scavenging. Nice!

[davec]

I have a Pete Weber phase 9 and 10 system, and I can tell you my 3 liter is one of the quietest ones on the track. At Lime Rock the limit is 86 decibels! While stock 930's and many other cars were being black-flagged, I ran uncontested the entire second half of the season, flat out.

And, I have tried many forms of straight mufflers, like the dynaflo, flomaster, supertrapp. I was never happy with any of them for all the right reasons; they didn't perform or were too loud.

I also have a spare set of 1 1/2 inch 911 headers and muffler that you can try to see if you like them. You may contact me off line, if you are interested. I am told they are Bursh.

Dave C

[David 23]

davec,
Does your Pete Weber system include his headers? Did you every try it with only the p9s on?

[davec]

Yes, with his headers. They are the main reason for the excellent flow. The phase 9's alone would be a bit too loud for me, but that is the way most people I know that have his system run. They have no backpressure issues, and their design takes a lot of the harsh sound and diffuses it.

[David 23]

Originally Posted by davec

Yes, with his headers. They are the main reason for the excellent flow. The phase 9's alone would be a bit too loud for me, but that is the way most people I know that have his system run. They have no backpressure issues, and their design takes a lot of the harsh sound and diffuses it.

My understanding (I have only seen the photos on his website) is that the P9s attach directly to the header outlets, and go straight out the rear? No crossover pipe, correct? I wonder if anyone has tried to add a simple crossover pipe after the header exit and before the P9s.
The photos of his headers look very elegantly designed. Are they as nice in person? Tube diameter?

[davec]

Yes, metallurgical works of art, IMHO. The phase 10 does just what you are asking, creates a chamber to equalize the pressure.