964 Race exhaust
 

Hello

Anybody who have tested or use the Cargraphic gt exhaust, any gain in Hp and nM over stock with primary muffler bypass?

My car is a 1992 RS n-gt with 306 hp 390 nM the engine, I am told by the previous owner it's not tuned (hard to believe)

Please recommend me the best exhaust with ore without headers

Sten

Or this one?
Don’t know the manufacturer

There is a debate over this sort of thing but I am fairly convinced that if the figures you post are correct, then you are more likely to lose poower than gain from an exhaust like this. To be precise, there is evidence that suggests you will lose torque although top end power might not be harmed.

Conventional wisdom suggests that the level of tune you have is about as far as you can go without making some serious changes, such as bigger injectors, either complex remapping or even changing to a programmable ECU, head work, cams etc.

I think you could be spending a lot of money for no reason.

On a standard engine (with standard engine management and injectors) a set of Cargraphic headers will pick up top end power and improve torque across the board, but that said the best result we saw with the Cargraphic headers fitted was on a remapped RS with a mass flow conversion, from memory it made around 313hp compared to the usual 305-308hp we have seen from similar cars on standard headers.

In contrast we tested three exhaust configurations on a stock RS engine fitted wth a 9m Motec system. With standard headers it made 338hp with cat bypass, with the best header set it managed another 7hp to push 345hp at 6250rpm with approximately 5-10Nm gains from 4000 up with a flatter torque curve; so whilst not setting the dyno on fire they definitely improved performance. That said, the same test on our 4.0 litre race engine found us 25hp and 35Nm, so if you are fitting the headers to a modified engine it would be reasonable to expect larger gains provided the design suits the engine specification.

Hello and thanks.

Any comments on the system on the big picture?

@ Colin
In the sort term I am thinking of just upgrade the exhaust on my RS
But on a bit longer sight I am dreaming of a race engine.
Are you designing your own header to the 9m 4 litre, ore is the Cargrapic headers suitable?
In my dream; I am buying a Ninemeister 4 litre set and build a new race engine, and then it would be preferable to use the same exhaust I am looking to purchase now.
Another question: If I install the 9m Motec on my engine, do I have to change injector’s as well?

Sten

The Cargraphic system is not a bad choice but it is expensive if you opt for cats and want a heater system. I have used the package on two different cars and have achieved reasonable results with both, so I think it would be ok for use with the 4.0 litre, or at least as good as any other conventional header set on the market. The only negative comment is that the first Carg headers we fitted (albeit a used set) have had to be crack repaired a few times on the main header pipes. Can I suggest that you also look at the B&B system which works just as well and is a neater package and comes with heater boxes on the header pipes if required, but be careful of noise limits with their twin outlet silencer and be aware that the one we tried had a boom to the sound at 2000-3000rpm. We have also tried the S-Car-Go headers on our 4.0 litre and found little advantage over the B&B or Carg headers.

We are intending to design and manufacture our own exhaust system for the 4.0 litre but this will be a top end product designed using CFD (computational fluid dynamics) techniques specifically tailored to the big engine specification - but it will definitely be better than anything else around even on a near standard engine. The downside is that the cost is likely to be double the price of one of these conventionally designed systems.

My advise would always be to fit the 9m Motec conversion first (yes - we do fit larger injectors otherwise you will not make large performance gains), then fit the headers of choice, then do the engine. The 4.0 litre runs the same Motec ecu and injectors as the standard 9m Motec conversion. The dyno graph shows the benefits of fitting headers to a 964RS with a basic 9m Motec conversion tested on our dyno - as you can see the improvements are marginal but definitely there.

[QUOTE=NineMeister]The Cargraphic system is not a bad choice but it is expensive if you opt for cats and want a heater system. I have used the package on two different cars and have achieved reasonable results with both, so I think it would be ok for use with the 4.0 litre, or at least as good as any other conventional header set on the market. The only negative comment is that the first Carg headers we fitted (albeit a used set) have had to be crack repaired a few times on the main header pipes. Can I suggest that you also look at the B&B system which works just as well and is a neater package and comes with heater boxes on the header pipes if required, but be careful of noise limits with their twin outlet silencer and be aware that the one we tried had a boom to the sound at 2000-3000rpm. We have also tried the S-Car-Go headers on our 4.0 litre and found little advantage over the B&B or Carg headers.

We are intending to design and manufacture our own exhaust system for the 4.0 litre but this will be a top end product designed using CFD (computational fluid dynamics) techniques specifically tailored to the big engine specification - but it will definitely be better than anything else around even on a near standard engine. The downside is that the cost is likely to be double the price of one of these conventionally designed systems.

My advise would always be to fit the 9m Motec conversion first (yes - we do fit larger injectors otherwise you will not make large performance gains), then fit the headers of choice, then do the engine. The 4.0 litre runs the same Motec ecu and injectors as the standard 9m Motec conversion. The dyno graph shows the benefits of fitting headers to a 964RS with a basic 9m Motec conversion tested on our dyno - as you can see the improvements are marginal but definitely there.[/QUOTE

Ninemeister,
I apologize in advance for asking a question that you probably have answered somewhere here earlier, but on the above dyno chart, why do you achieve maximum HP and torque on one set of lines at about 4700 rpms while on the other set of lines maximum HP/torque occurs closer to 6000rpms?

Dave,
The simple explaination is that the flatter lines represent the measured and corrected flywheel torque, the scale for which is on the RHS in Nm (to convert to lbft divide by 1.3558), whereas the steeper lines represent the measured and corrected flywheel power, scaled on the left in DIN bhp.

The red lines are the 964RS engine on Motec with stock heat exchangers and a cat bypass. The blue lines are the same engine with the header system fitted and the Motec re-optimised accordingly.

OK?

[QUOTE=NineMeister

OK?[/QUOTE]

Yes, I think so. Thanks.

Not Ninemeister, but I think that he may have misunderstood the ?, the pair of lines that peak at ~4700 is torque from 2 different cars
the pair that peak ~6000 are the corrresponding hp for the same 2 cars.

Any comments on the system in the big picture?
I don’t know ho makes it but I think its in Europe
I believe this vas originaly designed for gt 3, but not 100% sure.
Most of the tracks have 95 or 98 db limit and it is possible to mount extra silencer on the outlets, looks very similar to 993 silencers.

@ Colin
Ninemeister recomend the Motec 48 unit, but do you have a (Bosh) part number for the ijectors

Sten