9m Headers performance comparison
#1
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9m Headers performance comparison
We have just completed a series of dyno tests on a customer's freshly built 3.8 race engine which I figured you would be interested to see.
The story with the car is that it arrived at our workshop with a blown 3.9 engine which had a lot of damage to anciliary components, so rather than go down the route of repairing the motor with a new crankcase we simply started again with a fresh 964 block and used our off the shelf 9m Racing engine parts to build him a new Clubman specification race engine, in fact the only parts we retained from the original build were the Motec M600 management, 5 x Carrillo rods, camshafts, intake and exhaust system. The engine now has the benefit of 9m Racing 102mm Clubsport pistons & cylinders, 9m billet heads, valve springs & retainers; 9m intake system (already had Jenveys fitted, we added the 9m billet intake manifolds, airboxes and linkages).
So began the dyno tuning a couple of weeks ago as witnessed by the expectant owner (video of the day can be seen here: http://www.youtube.com/watch?v=w7oIyQUOJGs). As expected the engine made over 380hp but it came at the price of an extremely loud exhaust note from the originally fitted, US made 1.875" headers & silencers. We noted several dips in the torque curve, so after a few discussions & a weekend to think it over, the decision was made to fit the 9m 964/993 header & silencer package as I was convinced that it would make more power and smooth out the torque curve.
Today I finally managed to re-dyno the engine with the 9m exhaust fitted and whilst it was on the dyno I also took the oportunity to try several intake trumpet lengths. In comparison to similar engines running 9m Race cams, we found that the engine is performance limited at the top end by the camshaft so it's no surprise that the engine preferred the longest trumpet lengths to make the best of the midrange spread of torque. The power graph pretty much speaks for itself , the 9m headers eliminating the huge torque dip at 4700rpm (65Nm gain!) and a 10-15hp gain up to the 7600rpm redline.
The story with the car is that it arrived at our workshop with a blown 3.9 engine which had a lot of damage to anciliary components, so rather than go down the route of repairing the motor with a new crankcase we simply started again with a fresh 964 block and used our off the shelf 9m Racing engine parts to build him a new Clubman specification race engine, in fact the only parts we retained from the original build were the Motec M600 management, 5 x Carrillo rods, camshafts, intake and exhaust system. The engine now has the benefit of 9m Racing 102mm Clubsport pistons & cylinders, 9m billet heads, valve springs & retainers; 9m intake system (already had Jenveys fitted, we added the 9m billet intake manifolds, airboxes and linkages).
So began the dyno tuning a couple of weeks ago as witnessed by the expectant owner (video of the day can be seen here: http://www.youtube.com/watch?v=w7oIyQUOJGs). As expected the engine made over 380hp but it came at the price of an extremely loud exhaust note from the originally fitted, US made 1.875" headers & silencers. We noted several dips in the torque curve, so after a few discussions & a weekend to think it over, the decision was made to fit the 9m 964/993 header & silencer package as I was convinced that it would make more power and smooth out the torque curve.
Today I finally managed to re-dyno the engine with the 9m exhaust fitted and whilst it was on the dyno I also took the oportunity to try several intake trumpet lengths. In comparison to similar engines running 9m Race cams, we found that the engine is performance limited at the top end by the camshaft so it's no surprise that the engine preferred the longest trumpet lengths to make the best of the midrange spread of torque. The power graph pretty much speaks for itself , the 9m headers eliminating the huge torque dip at 4700rpm (65Nm gain!) and a 10-15hp gain up to the 7600rpm redline.
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Aye, it's been a saga alright from what I can gather.
The only problem I have is that by looking through other customer's engine dyno tests I know what we could achieve if we fitted a set of 9m Race cams (i.e. 30hp gain at 7000rpm), however it is also reassuring the know that Teo's current engine makes exactly the same power & torque as a 993RS-R type engine that we also ran on the 9m ITB intake and 9m Headers which was running Cup cams (from memory). That said,it will still be more than fast enough to keep his 3.0RS "exciting".
The only problem I have is that by looking through other customer's engine dyno tests I know what we could achieve if we fitted a set of 9m Race cams (i.e. 30hp gain at 7000rpm), however it is also reassuring the know that Teo's current engine makes exactly the same power & torque as a 993RS-R type engine that we also ran on the 9m ITB intake and 9m Headers which was running Cup cams (from memory). That said,it will still be more than fast enough to keep his 3.0RS "exciting".
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Or not as simple as that???
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No problem Jaime, the last crate engine we built was a 430hp 4.0 litre that ended up installed in a factory 993RS-R in South Africa. After it was tuned locally it managed to push his old aircooler 2 seconds a lap faster than a 2006 996RS-R around his local circuit, much to the driver's annoyance!
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That's right, it's the only way to be.
Here's a comparison between the similar 4.0 litre high lift engine in my 993RS against a stock 996GT3 RS road car, my engine running the same intake, heads & exhaust as Teo's engine above. Hopefully the fact that the 9m Race engines make tremendous mid range torque with a flatter curve than the factory GT3RS engines will also contribute to blowing away the myth that big HP n/a = gutless, undriveable, off-cam performance.
Here's a comparison between the similar 4.0 litre high lift engine in my 993RS against a stock 996GT3 RS road car, my engine running the same intake, heads & exhaust as Teo's engine above. Hopefully the fact that the 9m Race engines make tremendous mid range torque with a flatter curve than the factory GT3RS engines will also contribute to blowing away the myth that big HP n/a = gutless, undriveable, off-cam performance.
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Sweeeeeeet!! Can you share what a ball park $ figure/range on what a turnkey solution like this cost? No core exchange... US$20K, 30K, 60K?
Last edited by Wachuko; 04-07-2009 at 05:27 PM.
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A 3.8 race engine build can cost anything from £20k to £30k depending on specification, whereas the high lift 4.0 litre with every known option will come in somewhere around £45k, including exhaust, intake & anciliaries but excluding the donor engine & Motec management system, so your guess is right in the ballpark Jaime.
As Bill says, Geoffrey is our 9m representative on the Eastern Seaboard and is more than capable of building similar engines from 9m Racing components.
As Bill says, Geoffrey is our 9m representative on the Eastern Seaboard and is more than capable of building similar engines from 9m Racing components.
#14
A 3.8 race engine build can cost anything from £20k to £30k depending on specification, whereas the high lift 4.0 litre with every known option will come in somewhere around £45k, including exhaust, intake & anciliaries but excluding the donor engine & Motec management system, so your guess is right in the ballpark Jaime.
Any improvements for the tip as well? Fit the 997 turbo's tip?
Thanks
Andrew