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Discussion Starter #1
In the way of bringing by car back to life, I've chased down a set of catless headers from the older style exhaust.

The wrecker I'm getting them from has multiple sets. If anyone is interested I can get some and modify them to bolt up to the newer flange so that they would drop in. I can also get them ceramic coated and/or wrapped before sending them over. It would probably cost between $1000-$1600 USD depending on what you want done. I don't know how many sets they have, but I've found them in a few places so I know I can do a few before they're all gone. If you're interested drop me a PM.

Cheers
 

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Just out of curiosity, when was the 4200 produced w/o headers that included the cat? Presumably the US missed out on this for the entirety of the model run.
 

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Discussion Starter #3
I'm not 100% sure on this so don't hold it against me!

I think pre-05 euro cars had the catless headers. I think all the North American cars had the cat in header for emissions as it is hotter closer to the ports so it's better at cold start. I believe that the euro cars followed suit for reliability as the lower primary header was prone to failure due to road impact.

The negative result is the primary header length is right for a car doing >12000 RPM and serves no purpose. As it is, the Larini and catless headers are shorter than I would normally spec out, but $1500 is better than $8k for a custom set!
 

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I believe the US spec versioned Gran Sport do not have a center resonator...sorry, this might be off topic.

Kindly,
Stephen
 

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My $.02 is to either hollow out the pre cats from the factory exhaust manifolds, or go with Larini headers. Any competent exhaust shop can cut open the cats, drop out the slugs, and weld back together for around $300 without having to remove them from the car. If you want to do headers, then go with Larini from FD. They're only $2900, will bolt on to the factory exhaust, and they're designed to perform, the result will be much better than the euro manifolds. The header swap is QUITE labor intensive, and definitely worth the extra investment for a better product.
 

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Discussion Starter #6
Other than the ceramic coating - I can't see any functional differences between the OEM headers and the Larini ones so it becomes quite hard to justify the price. Further to that I'll be modifying them to suit my own uses which is much more justifiable on a cheaper set.

Gutting the existing cat will sound nice but with the headers being so short I won't gain a lot from the effort in a functional sense either.

I mean for what its worth to anyone else there are a few things I'm thinking of doing with some pros and cons of each.

Cutting off the flanges and running the exhaust into an 8-1 collector
Pro:
  • Better performance
  • Will sound like a flat plane V8
Con:
  • Will require a stand-alone ECU or a custom flash tune
  • Lose the V8 rumble
  • Effort
Running a X-pipe early at the base of the headers
Pro:
  • Better Performance
  • Will still sound like a cross-plane V8, but less so the close it gets to the headers
Con:
- Can't have it too close or there will be emotional problems with the ECU.

Cutting off the flange and lengthening the headers to the steering rack (if I do this I'd replace the X-pipe with a double-Y)
Pro:
  • Will exaggerate the cross-plane sound
  • No ECU issues
Con:
- Only a moderate change in performance compared to the other two

Regardless of what I do, having a cheaper set to cut up will be the easiest way to go, and I don't have to do the work to clear the engine block which is what would take up most of the time. I'll probably lengthen the headers and go for the double-Y to drive home the unique sound of the engine since I'm not building a race car so I'm not chasing every little kW gain.

For anyone who is interested - the best set of aftermarket headers I've found are made by a shop called Best Mufflers in Sydney. They're stepped and tuned length, unlike the Larini/OEM set which are about half the length they should be. Maserati Gransport Custom Headers & Performance Exhaust System The price was $7k AUD (about $4800 USD) and he can build them again as they were built on a jig.
 

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Whelp, you've got it all figured out, let us know how it turns out.
 

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Discussion Starter #8
I spent a few years working on intake and extraction for racing, its something I really enjoy doing. As I'm chasing up headers for my own car and found a surplus I thought I'd offer to share the love since I can modify them to be bolt in for half the cost of the Larini headers.
 

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More power to you man, I think it's great that someone wants to keep developing for this platform. Sounds like you have the means and expertise in both fabrication and tuning to do something really useful, like a centrifugal supercharger setup, now that would be cool.
 

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Be very surprised if you get significantly better performance and a flat plane sound, but....

C
 

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Discussion Starter #11 (Edited)
More power to you man, I think it's great that someone wants to keep developing for this platform. Sounds like you have the means and expertise in both fabrication and tuning to do something really useful, like a centrifugal supercharger setup, now that would be cool.
Low volume is the enemy of aftermarket parts. A friend of mine is looking for cars to make kits for (he is currently doing E92 M3s) but I wouldn't be able to convince him to do this car if I tried - it would just be bad business ?. I have plenty of stuff to sort out first, but I've been talking with a colleague to make an ITB kit and revise the intake at some point. I'm keen to do it but the effort is very high, and my car still has a few issues to resolve before that becomes a priority.

Be very surprised if you get significantly better performance and a flat plane sound, but....

C
Please forgive me for being overly reductive because it is more complicated than this but I should be able to make it clearer.

The biggest contributor to exhaust temperament is firing order, and the easiest example of this is a boxer rumble compared to a standard 4 cylinder. Newer Subaru boxers don't have the characteristic rumble that they were known for. The reason for this is that the firing order on a boxer 4 is the same as an inline 4 and the rumble came from unequal length headers used to save cost in the awkward port arrangement of a boxer. The headers manipulate the way the firing order is heard; so in a situation where you would normally hear 1-3-2-4 you might hear 1-2-3-4, and the pulses overlap on every alternate stroke. So instead of da-da-da-da you get dada-dada. This video is a very clear example.

When it comes to a cross-plane and a flat-plane crank, wikipedia says it perfectly The way in which a flat-plane works within a V8 engine is more like two in-line 4-cylinder engines mated together, with the firing order of each order being in a Right-Left-Right-Left-Right-Left-Right-Left pattern.'

What this means for sound is that each exhaust pulse is 45 degrees from the last and is on the opposite bank, so you have a smoother tone. In contrast, a cross plane crank means that on each bank two cylinders on the same bank have to overlap into the same exhaust manifold by 45 degrees. So instead of da-da-da-da-da-da-da-da you get da-dada-da-dada-da which is the characteristic American V8 rumble. Wikipedia gets it right again Crossplane - Wikipedia . This is also why only cross-planes have x-pipes, it is used to balance the firing order in the exhaust to improve efficiency and prevent drone.

This video will help visualise the overlapping pulses

At the most fundamental level, the difference in temperament from a flat-plane compared to a cross-plane can be attributed to this. Building a set 8-1 or 180 degree headers means you eliminate the distinct overlapping sound because you equalise the pulses between the banks in which case you have the exhaust pulses 90 degrees apart just like in a flat plane engine. The performance improvement can be quite substantial and becomes more noticeable at higher RPM. Just for a bit of car porn, here is the 180 degree headers used on a Ford GT40.

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And if it helps convince you further, here is a video of a 458 on the dyno
and an LS7 with 8-1 headers
. Keeping in mind different cams and displacement, etc - the LS7 sounds way more like a flat-plane than a cross-plane. A standard LS7 for reference
.

As a general rule, if you're wanting to tune an exhaust for sound instead of performance you try to induce unusual adjacent overlap in the muffler by having chambers of different lengths to resonate and mix pulses from different points in time as the pulse takes different times to traverse different parts of the exhaust system. Engines with this behaviour intrinsically built in are I-5s, V10s, cross-plane V8s, and to a lesser extent I-3s and V6s, which why they tend to sound more interesting than intrinsically balanced I-6s and V12s.
 

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Low volume is the enemy of aftermarket parts. A friend of mine is looking for cars to make kits for (he is currently doing E92 M3s) but I wouldn't be able to convince him to do this car if I tried - it would just be bad business ?. I have plenty of stuff to sort out first, but I've been talking with a colleague to make an ITB kit and revise the intake at some point. I'm keen to do it but the effort is very high, and my car still has a few issues to resolve before that becomes a priority.
Im confused. If you can fabricate and tune a set of ITB's, you can do the same for a supercharger, in a quarter of the time, cost, and effort, and yield 100% better results.

I think your exhaust theory is slightly off, 180 degree headers would definitely yield what you're looking for, but an 8-1 will he disappointing. Let's hear a clip of a stock LSX next to another stock LSX with 8-1 and you'll see what I mean. I like the design of the headers you posted earlier from the Aussie shop, with the exception of them being one piece. There are too many maintenance and repair scenarios where the mid pipes have to come out, and to turn a 15 minute job into a 10 hour job for a possible performance gain, that'll likely have to be tuned, which is next to impossible, doesn't seem worth it. Regarding your opinion on the Larini headers, have you ever seen a set in person? Have you compared them side by side with Euro manifolds, or are your comments speculation based on a few pictures and literally no published specs for either?
 

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Discussion Starter #13
We're way off topic here - all I wanted to do was let people know I found a bunch of the catless OEM headers and would be happy to modify them to bolt straight onto the newer style flange. It would be half the cost at least of the Larini set, and the performance would be equal to the point of being immeasurable in difference.

To answer your questions though:

The cost of a single supercharger would cost more than a whole ITB installation, and that says nothing to solving issues with oil supply, belts, intake routing and intercoolers. Supercharger Units . And sure, you'll get as much power as you're willing to put in boost but I also don't want to find out where the limit is on my own engine, and I doubt anyone would volunteer to be that guinea pig either... Then there is also the aesthetic point, that I just prefer the NA induction sound.

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I might have misunderstood you, but it is two 4-1 headers and not a single unit? When I spoke to him he said there were some clearance issues around the oil filter so they are very snug in the engine bay.

I haven't seen the Larini set in person, but then I also never commented on their quality. What I said was that I'm planning to cut them up anyway and that it was hard to justify the costs. Functionally the primary tubes are a bit longer on the OEM set then the Larini (and I've seen a setup like below). The black line is where the Larini primary tubes terminate. I doubt you'd be able to measure that difference on a road dyno though. Unless Larini want to send me a set for testing I doubt we'll ever get a side-by-side on the same car anyway.

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I did speak to the Australian distributor for the Larini parts, and though the price was a bit better that way than sourcing them from the US, it was still too pricey to justify. I chased up a few wreckers locally and in the UK but wasn't able to find a set. I did find a set of mufflers and cats though.

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Discussion Starter #14
Our engine is similar in spec to the BMW S65 V8 so I spoke to my friend in Sydney about the costs of supercharging these cars. He is a VF partner or supplier or something like that so fits their kits to a bunch of different cars.

VF engineering use Vortec superchargers and on the S65 they get a claimed improvement of up to 230hp for $9500 USD BMW (E9X) M3 Supercharger (2008-2013). Their cheapest kit is 130hp for $6k USD. They sell these kits with relative volume and they're completely bolt on. To try and make something like this bespoke would cost at least double that to include labour and fabrication, and unless there were volume to justify manufacturing you wouldn't really be able to bring it down.

So yeah, somewhere around $15k-$20k USD to get your Gransport up to 600hp assuming you don't send a rod into space...

Apparently Novitec do a supercharger kit for ~$30k USD for the 4.7L engines, which you could probably make fit with less effort if you're keen...
 

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Discussion Starter #16
Yes you will. There are several ways around it though.

The best would be to replace the secondary cat with a good high flow cat and put the emissions O2 sensor post that with a proper O2 extension. That is how Larini solve the problem if you buy their headers.

If you wanted to be dodgy you could install a minicat to fool the sensor, if you wanted to be dodgier you could code out the CEL condition, and if you wanted to be dodgiest you could do that with a full decat.

I'd probably go with the first option...
 

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Wont you get check engine lights if you delete the primary cat?

I know deleting secondary is not a problem
If you want to run catless, the simplest and least expensive way to deal with the CEL is an oxygen sensor spacer. You can even drill out a pair of spark plug non foulers and use those for $10.
 

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Wont you get check engine lights if you delete the primary cat?

I know deleting secondary is not a problem
[/QUOTE
Wont you get check engine lights if you delete the primary cat?

I know deleting secondary is not a problem
I used these, I've done over 2000km,s now, no Cel cost $25 au each. I got them from ebay. I sugest getting the ones whith the 90 degree off set otherwise the ends of the o2 sensors touch each other.
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Our engine is similar in spec to the BMW S65 V8 so I spoke to my friend in Sydney about the costs of supercharging these cars. He is a VF partner or supplier or something like that so fits their kits to a bunch of different cars.

VF engineering use Vortec superchargers and on the S65 they get a claimed improvement of up to 230hp for $9500 USD BMW (E9X) M3 Supercharger (2008-2013). Their cheapest kit is 130hp for $6k USD. They sell these kits with relative volume and they're completely bolt on. To try and make something like this bespoke would cost at least double that to include labour and fabrication, and unless there were volume to justify manufacturing you wouldn't really be able to bring it down.

So yeah, somewhere around $15k-$20k USD to get your Gransport up to 600hp assuming you don't send a rod into space...

Apparently Novitec do a supercharger kit for ~$30k USD for the 4.7L engines, which you could probably make fit with less effort if you're keen...
I'm beginning to think you're either a fantasy reader/know it all type, or someone who's enjoyed some success building and tuning Hondas or Mitsubishis or something, who assumes the principles will align here. There isn't a planet where fabricating bracketry to mount a self contained Rotorex into the belt system is a quarter the amount of work and complexity, than it is to build an ITB setup from scratch. To get them efficient, they have to be built, tested, and redesigned countless times, then you get the daunting task of trying to tune them for driveability, then you get to cross your fingers and pray that your exhaust design is even reasonably matched. Furthermore, your car isn't a Ferrari. It never will be. Not with an exhaust that may make it sound like a flat plane crank, not with an intake setup that you probably wont hear over the exhaust, not even with an F360 TCU... I don't mind your ambition, but you're making a LOT of assumptions based on your VERY limited actual experience if any, and ignoring advice given to you by people who have worked on these cars for nearly 2 decades, owned and modded several, many different times, etc. Prove me wrong though, I'd love to see it.
 

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Discussion Starter #20 (Edited)
Rightyo spaghettio.

But back to the point - if anyone wants some cheap headers modified to bolt in, drop me a message...

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P.S. The BMW S50B30 was the first production engine to crack 100hp/L for road use in 1991. The Honda F22C/1 was 124hp/L in 2000. Ferarri only matched that output with the 4.5L F136F in 2010. None of the Maserati engines have hit that specific output yet so I'm not really sure you're making much of a point. All engines obey the same laws of physics last time I checked.
 
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