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Discussion Starter #1
Finally, after a project that took months, a Kreis-sieg racing exhaust has been installed in my 04 Coupe. The Kreissieg mufflers come with a vacuum system that allows the driver to flip a switch between Silent and F1 modes. In F1 mode the exhaust bypasses muffler chambers and exits with a scream reminiscent of F1 racing--more precisely, with the Maserati V8 it sounds like Formula One motorcycle racing with the volume boosted, if you can imagine that.

See pictures of the system at

http://www.kreissieg-usa.com/index.php?page=detail&brid=9&mid=.33&cid=51&oid=53&pid=63

I also purchased the optional "set of pipes including racing catalytic converters" Kreissieg offers to supplement their cat-back system. You can see the "racing cat" in image 4 of the link, it is the little cylinder sitting between the exhaust pipes. It is really a small "dummy cat" that processes a tiny portion of the exhaust flow and lets the sensors and computer see what they need to avoid a check engine light and other OBDII problems. The system should be street legal and pass computerized emissions tests.

Unfortunately, the whole manifold-back system I just described had pipes too large in diameter to join to the exhaust manifolds (headers) in my U.S. Maserati. The stock U.S. exhaust system has smaller headers that bottleneck in pre-cats before even entering the main catalysts further down. The European Maserati headers I eventually obtained are in a different league; they have larger volume tubes to precisely match the piston stroke displacement and produce an effect not unlike turbocharging.

Weight of all the new parts is 137 lbs, just a little less than stock. However, the net result is a power gain that I think must be at least 100 HP when the car is driven all out. Honestly, it feels like driving my neighbor's Ferrari F430 weighted with a couple of passengers--and it sounds twice as fast as that car. In fact, the sound is so loud and extreme it elicits only reactions of fear and anger on the highway. The Coupe is not what you'd call a daily driver anymore, and I am so much happier as a result. I could go on and on, but this post is already too long.

Here are pictures of my Coupe showing the vacuum system, Kreissieg tips and the toggle switch inside the cabin. A couple of sounds clips follow in my next post.
 

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Discussion Starter #2

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Sounds very nice. But are you sure about a 100hp gain? Doing the same on my M3 including cats gave me a 5-8% gain at most. Nonetheless, pretty impressive.
 

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very nice! how much is the system + install?
i'd like to see how much changes in HP and Torque with the system in normal and F1 mode vs stock.
the only down side i can see is the switch can be better looking.
 

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what it all cost

Thanks for your nice feedback. The cabin switch is indeed crappy and I'm glad it's hidden under the cigarette lighter door.

Costs:

Kreis-sieg cat-back system, pipes + racing cats = $9,700
New Maserati headers = $4,200
Installation at Eurocar-Werk in Houston = $4,400 (a bargain)
Racing ECU application = $1,500 (already had the basic ECU reprogram)
Total = $19,800.

It's interesting that Modena Performance adds 162 horsepower with superchargers for $36,000. So in comparison, if you get what you pay for, I bought about 90 more horsepower. I remember how a 5% power gain felt with ECU reprogram and Fuchs mufflers, and honestly this feels like five or more of those added together, especially above 5000 rpm.

My mechanic says a lot of power gain is due to the new headers, which unlike the U.S. headers are correctly matched to the piston strokes to produce a kind of turbo effect on the motor. Plus, the nasty pre-cats in the wimpy old headers are gone too. The May 2006 Modified Luxury and Exotics magazine has an article on this topic:

"On the factory (car) there is a pre-cat and then the actual cat. Combined, the reduction in exhaust flow is staggering. To put the difference between the (racing) set up and the factory set up in proportion, it is like comparing a Class 5 rapid with a garden hose."

They are discussing exhaust modifications on an Audi RS6 similar to those I made, and they measure a gain of 106 bhp and 200 ft-lbs of torque with that V8.
 

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It certainly sounds great under acceleration, but I am massively skeptical of exhaust mods adding that type of power increase. Dynos are notoriously inconsistent, so only a before and after on the same dyno would really be indicative of improvement, and I doubt you did a "before". Next best test would be on the track - raw acceleration. I would get a GTech or take a trip to your local drag strip and see what the 1/4 mile brings. My gut instinct would suggest something more in the range of a 10% improvement (e.g. 30-40 HP or so). There's almost no way to obtain that kind of power boost (100 HP) without also increasing inflow as well. In any case, it sounds sweet!

Anyone know what kind of power a Trofeo makes?
 

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i was going to ask exactly the same thing but didn't want to be the one to start... cos he just spend $20k on a mod that i will never spend on a maserati.

from italiaspeed:
Maserati Gransport Trofeo:
Technical Specification: Engine 4.2 litre 90 degree V8 normally aspirated; Max power 425 hp at 7200 rpm; Max torque 460 Nm at 4500 rpm; Top speed over 180 mph; 0-62 mph 4.5 seconds

Maserati Trofeo Light
Horse Power 430 H.P. @ 7000 Rpm
Torque 339 Lb.Ft. @ 4500 Rpm
displacement 4244 Cc
Curb Weight 2546 Lbs
Top Speed 177 Mph
 

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it's quite possible the mod could introduce 100HP gain at flywheel and of course 40 or more HP's at wheel :) power to weight ratio may be a better gauge.

Expensive or not (rather subjective), very brave and awesome!
 

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Discussion Starter #10
Thanks, haha. It took tenacity and independence of mind to complete this project, so your remark is appreciated.

Regarding the implication I wasted $20k: The system is less expensive than a mistress, and far more enjoyable.

I started this thread to provide a little information to anyone contemplating such a modification. I am surprised to see reactions of anger in this forum. I was not trying to demean the superb performance of stock Coupes.

Work was done at Eurocar, where they have a division that tunes Porsches and Ferraris for racing. They are veterans who get a ballpark figure for power gains by driving the cars before and after modification. They estimated my peak power gain in the neighborhood of 25%. (I can feel the added power diminish below 5000 rpm, so while a 1/4-mile time is interesting it doesn't tell peak power output.)

I ran one of the responses above by the head at Eurocar and he suggested I clarify the following: 1) Most European (but not American) cars see a power increase of 10-15% when correctly designed racing headers are installed. 2) It's not only what was added to my car, it's what was removed. Imagine putting U.S. headers and stock exhaust on a Trofeo, watching max power drop 25%, then performing a miracle by putting back the racing exhaust. Put another way, the power gain isn't 25% x 400, it might be 25% x 320 bhp. 3) Post pictures of the shrunken U.S. headers, and constrictions in the stock exhaust (follows).

Peace, everyone. Anyone who's ever in Houston can drop me an email and take the monster for a drive.
 

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Discussion Starter #14
thebimbo said:
Given a Euro-spec GranSport what would be the *minimum* you would do (so still road legal)??
Kreis-sieg mufflers + racing cat/pipes only, these will fit your headers. It would be heaven on a GS.
 

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CDF said:
...I am surprised to see reactions of anger in this forum.... They are veterans who get a ballpark figure for power gains by driving the cars before and after modification. They estimated my peak power gain in the neighborhood of 25%. ...
i dont think there is any anger... you should see some other forums when someone makes a claim.

going back to the topic, besides the veteran butt dyno report of 25%, any graph before and after the mod? they sold you a $20k mod so at least they can afford a couple of dyno runs.
 

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Thanks for sharing this information. I love reading about modifications to Maserati's. Any chance at seeing a video?
 

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Discussion Starter #17
GregD said:
Any chance at seeing a video?
Not right away, no video recorder. There are videos of a Kreissieged Spyder on the website I mentioned, but the system really sounds different in person.

M!, you are trying to keep things honest. A first-rate account would include dyno results. I'll see what I can do.
 

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CDF said:
M!, you are trying to keep things honest. A first-rate account would include dyno results. I'll see what I can do.
of course! you spent that much, they better not just tell you from their butt that it feels 25%+. where? at what rpm? how?

it would be interesting to see the dyno results.
 

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I am stoked for you on your success in building a killer exhaust system. It sounds so good, I will post mine with straight pipes after work tonight, still deep yet raspy and more f1ish than before. Your car definetly sounds like an all out screamer,,SWEET!

The system I was telling about on the other thread was custom made for me (search "leonardo exhaust" its the first thread if anyone wants to catch up or hear sound clips. I live in Las Vegas and happen to know a very skilled exhaust fabricator that works on lots of exotics.

I would be very interested in a pair of headers like you bought. How can I order some? was it an engine out installation? Do you have comparison pics of old and new? Did you have any problems with engine lights after swapping headers? did you go with the BMC airfilter too?

I plan on taking my car for a Dyno Jet soon and I will post my results here. Do you have any plans to dyno yours? It would be great to see the differences, we all know that stock HP is somewhere @ 320rwhp. Mine would be dyno'd with strait pipes and yours with programming and headers.

see you on the next thread!

 

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Discussion Starter #20
some answers

Robb373, I appreciate the positive comments. We are lucky to have found custom shops willing and able to do this fancy exhaust work; although it sounds like you directed the work yourself.

Some answers to your questions:

The upgraded headers are made by Maserati. Nobody else makes headers for our model of car. Wish I'd taken comparison pictures of the old and new headers, the difference is incredible. The bad news is Maserati cannot import these into the U.S. due to emissions laws. Unlike stock U.S. headers, these ones don't have built-in pre-cats, and are too big in diameter to join to the next stage of the stock U.S. system.

In any event, you can't order these headers, you get them on the "grey market." I could tell you where to get them, but then I'd have to kill you! (Just kidding. If you want to try I will pm you the info.)

Not an engine out job, but a new wiring loom has to be contructed for the O2 sensors to reach the racing cat. The dummy cat does well avoiding CEL's, but I get one minor code every 2 weeks or so. This can be turned off permanently from inside the ecu, or just reset with a scanner every couple weeks.

I installed BMC. Best way to do it yourself seems to be by removing front wheel and going in through the wheel well (see thread on different methods).

Yes, still need to get dyno numbers. Be a couple weeks due to my impending move.

Good luck with future work on your system.
 
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