Catless Headers for 4200/Gransport

lambertius

Junior Member
Messages
78
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
 

Zep

Moderator
Messages
3,647
I assume you mean Aus $?

I some important things to note regarding moving from US spec to EU spec headers.

- the lambda sensor wiring is routed to the loom on the radiator for US spec cars. It has to be stripped back to route it to the EU spec cat positions.

- fitting EU spec headers to US spec ‘squish’ pipes means you have to retain a cat in those pipes. Plus there are no bosses for the lambda in the standard pipes so these will need modding.

- If you don’t want to mod your original pipes you would need to go for Larini or other options to fit the lambda sensors. At which point you might as well get the correct 4 bolt squish pipes for the headers and save modifying the headers to suit.

- The heat shielding under the engine is different from the two manifold types - you will need this too.
 

lambertius

Junior Member
Messages
78
I converted it to USD since that is more common, I thought it would be easier that way. I found the parts for between $1k-$1500 AUD between a couple of wrecks, plus some allowance for materials and time if someone wants them modified.

Thanks for the info, it always helps to be prepared!

With the lambda wiring I'm planning to solve it with some extensions. I spoke to the Australian rep for Larini when I was looking at options and he said that is how they normally get past it.

For myself I'm going some custom high flow cats, and was going to do a similar solution to the Larini high flow cats but I think its good to know for anyone else that if they plan on keeping the flat pipes they'll need a bung installed. The other thing you could do is install a mini cat, so I could put another boss in the catless headers if someone wants that.

I didn't know about the heat shielding so thanks for that! I'll chase that up, but I'm planning to ceramic coat mine and wrap them to help control the heat as well!
 

conaero

Forum Owner
Messages
30,301
Also worth noting that the headers are dual skinned. Used parts may rattle. There is a fix where you drill and plug weld to secure the two skins together and stop them rattling.

It might be worth having this done before you fit them.
 

lambertius

Junior Member
Messages
78
Oh thanks for that! I was planning on cutting off the collector to extend them further and that would've been an unwelcome surprise! I'll definitely make sure they're secured now I know. I don't suppose there is a thread with pictures or clearly describing the fix you can link?
 

Zep

Moderator
Messages
3,647
I converted it to USD since that is more common, I thought it would be easier that way. I found the parts for between $1k-$1500 AUD between a couple of wrecks, plus some allowance for materials and time if someone wants them modified.

Thanks for the info, it always helps to be prepared!

With the lambda wiring I'm planning to solve it with some extensions. I spoke to the Australian rep for Larini when I was looking at options and he said that is how they normally get past it.

For myself I'm going some custom high flow cats, and was going to do a similar solution to the Larini high flow cats but I think its good to know for anyone else that if they plan on keeping the flat pipes they'll need a bung installed. The other thing you could do is install a mini cat, so I could put another boss in the catless headers if someone wants that.

I didn't know about the heat shielding so thanks for that! I'll chase that up, but I'm planning to ceramic coat mine and wrap them to help control the heat as well!
No problem. If you are making a custom cat pipe I am wondering why you are modifying the manifolds. After all, you can make them to fit the standard collector.
 

lambertius

Junior Member
Messages
78
90% of the work is clearing the block. These ones can just be put into place and then everything tacked in place by hand without any faffing about with hose clamps and planning weird routes through the engine bay. The flanges and EGR are in the right place already so it really just drops the effort to customise the headers. All I want to do is extend them to be a more appropriate length so this was the easiest way to do it.

edit: Sorry, I realised I misunderstood your question - the headers with the cat are too short to be useful, they're basically only useful for a car with a 12 000 RPM red line. So I want to replace the headers, and put a high flow cat in a place that allows the headers to be a useful length.
 
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Zep

Moderator
Messages
3,647
90% of the work is clearing the block. These ones can just be put into place and then everything tacked in place by hand without any faffing about with hose clamps and planning weird routes through the engine bay. The flanges and EGR are in the right place already so it really just drops the effort to customise the headers. All I want to do is extend them to be a more appropriate length so this was the easiest way to do it.

edit: Sorry, I realised I misunderstood your question - the headers with the cat are too short to be useful, they're basically only useful for a car with a 12 000 RPM red line. So I want to replace the headers, and put a high flow cat in a place that allows the headers to be a useful length.
The question was, why modify the EU spec headers, when you can make your custom cat pipes to connect to the standard 4 bolt collector on the EU manifolds. It could save you some time and money.
 

lambertius

Junior Member
Messages
78
I want to get the primary tubes to be as close to 1.3m is as practical. It should push the performance band closer to the 4000-5000RPM instead of the outside the engine's performance band.
 

Zep

Moderator
Messages
3,647
Ah, I see. It will be interesting to see what results you get. I recall someone building a custom long primary manifold and the benefits were negligible.
 

lambertius

Junior Member
Messages
78
Cheers, I'm not expecting it to change the peak power at all but to move the peak torque further down. I'm hoping clearing the cats and the flat section will give me about 5-7% more breathing room across the rev range though!

Truth be told I'm mostly doing it to improve the sound...
 

Spartacus

Member
Messages
2,882
I would be suprised if you get any more performance out of that engine . Its been tried many times to no avail . Good luck though .
 

MAF260

Centenary Club
Messages
6,706
Read my post from a while back about the modifications I did to mine. The increase in power was minimal; thankfully I changed my manifolds to eliminate the risk of the OEM cats breaking up and also to add more noise.
 

Navcorr

Member
Messages
3,217
Are you saying that Larini's marketing pitch isn't 100% truthful?! o_O
Heaven forfend :smile:
Your notes on Maseratilife make interesting reading.
 

lambertius

Junior Member
Messages
78
Read my post from a while back about the modifications I did to mine. The increase in power was minimal; thankfully I changed my manifolds to eliminate the risk of the OEM cats breaking up and also to add more noise.

I already did :) https://www.sportsmaserati.com/index.php?threads/gransport-exhaust-mods-picture-heavy-thread.13177/

You never posted the dyno charts, but there is still time! You said that you got 20hp more in this post https://www.sportsmaserati.com/index.php?threads/gransport-exhaust-mods-picture-heavy-thread.13177/page-9#post-319339 compared to the previous post https://www.sportsmaserati.com/index.php?threads/gransport-exhaust-mods-picture-heavy-thread.13177/page-5#post-312934

I know you might think that isn't much, but I think you're looking at it the wrong way. That represents a 5% improvement over the stock peak power on a low-revving high-compression naturally aspirated unmodified (as in you haven't changed the cam, compression, tune etc) engine. Without the dyno chart its impossible to tell what the real story is as well. Peak torque occurred on mine at <4500 RPM so that tells me that the header length should be trying to support the point where the engine is breathing the hardest. The chart below is from a system I modified where I logged the dyno as a percentage improvement. If I focused on the peak power I could be disappointed with a 16% improvement but the peak percentage change was at 5200 RPM at 23%! This was a full induction and extraction system, and the engine was only 75hp/L at the start so there was room to move. The point I'm making is you may actually have improved the output by more than 5% and that tells you more about the function of the engine than a peak number.

If you still have the before and after print outs please share them, it will really help me work out what is going on!

If I can get a 7% improvement over a base run that would be about as much as I could hope to see while keeping split headers. If you went mental with 8-1 or 180-degree headers you'd reasonably expect 8-10% over a baseline as the peak change, though you probably wouldn't see much if any change at the peak power point. They wouldn't sound anywhere near as fun though...

64522

Heaven forfend :smile:
Your notes on Maseratilife make interesting reading.
I was hoping that there would be silent viewers that might find it interesting. Its a shame people are on forums just to be disparaging.
 

MrPea

Member
Messages
2,314
Read my post from a while back about the modifications I did to mine. The increase in power was minimal; thankfully I changed my manifolds to eliminate the risk of the OEM cats breaking up and also to add more noise.
Did you really manage to get more noise, Maf? I don't really recall.