Just a question for my understanding: how can rear muffler boxes, supposed to silence exhaust gases on the rear of the car, be related to thermal reactor headers in the engine bay?
Then why not simply use the same mufflers as on the European cars? Did the thermal reactors with an air-pump create a condition where the European mufflers become too hot? It’s curious that the “boxes” on the US mufflers are pretty much empty surrounding the exhaust pipes.
I considered eliminating the rear mufflers and ran the car without them but did not like the sound at all. To me the sound was too loud and annoying. I do not mind a somewhat loud exhaust but it needs to sing, not yell. Granted the car did not have the back glass nor exhaust tips. Ivan
How about the euro headers; are they on yet? Huge difference! I am now running the QS headers without the rear boxes. She sounds absolutely fabulous. FWIW removed the rear boxes from my Euro Bora years ago. Same brilliant rich throaty result. No droning or unwanted/excessive loudness from either car.
Same experience with my Indy. No rear muffler/silencer, only the two successive resonators per line. In the shop, I compared it to the sound of another Indy and also of "European" Bora's, with the standard exhausts. It's of course louder but still reasonable, except may be at full load but you don't drive often in these conditions. Imho, the sound of this V8 without silencer(s) is really enhanced and indeed fabulous at all regimes: rich and throaty at idle, and roaring whith also higher frequencies at high rpm's and full load, and no drone whatsoever at intermediate regimes. Plus some nice backfiring when you take off the gas (I don't abuse) As it passed the "Controle Technique" as such without any rematks, I will certainly keep it as it is!
Interesting sounds you guys are getting from your exhaust setups, thanks for sharing.. - My Kh has good Euro headers, then two good straight 'Cherry Bomb' or GlassPack resonators, and just pipes with Y's to the exhaust tips after that. But the pipe connections have gasket gaps and pinholes in the welds. This all is loud, barking and unsophisticated sounding. I'm replacing everything behind the header trumpet flares. After recovering from pricing up a new Ansa center muffler assembly and rear resonators, I'll be experimenting with a $100-to-$200 FlowMaster Super 50 or 40 Series dual-dual center muffler and have my local shop fabricate the necessary pipes and flared flanges to mate up to the headers and tips.. - My Bora has Euro headers to the US transverse mounted muffler and no resonators after that - it sounds wonderful. Cheers, - Art
To be clear the US headers not only strangle the engine but raise temperatures, particularly at high speeds. When I did top speed runs with my US car the temperature shot up every time from 80to 90 celsius the same way because the reburning chamber (that primitive ancestor of the catalytic converter that looks like a rugby ball) just a couple of inches from the engine block gets very hot as the gases don't come out of it as fast as they get in and that heat then crawls back along the exhaust pipes towards the block. Had I been able to keep my car the next task list item was just that, Euro headers. A very competent engineer in Germany went for a fast Autobahn run back in 2009 with an enthusiast who owns or owned a US automatic Khamsin. When trying to max it out they were faced with serious temperatures and had to back off. Fitting Euro headers solves the temperature issue. The car will also tolerate very high summer temperatures much better. All those who have done so have confirmed it and the engine then runs better, and performs even better which is normal as any thermal engine is an elaborate air pump. No one has reported high speed temperature issues on Euro and RHD K's: I wonder why;-) The US headers are no less of a gross heresy imposed on US K's than the US bumpers.
Did you have the air pump still connected? These were what was known as thermal reactors the precursor to catalytic converters which also caused overheating during the early years of pollution control development. On my Bora the PO had repaired them by welding them where they had cracked and then attempted their own homemade insulating sleeving. It didn't work. It's also why there are elevation warnings on the pollution controlled cars about operating these above 4000 ft. Imagine the fun surprise I got trying to take my newly acquired, low mileage Bora back home from Oklahoma City to SF as I went over the Berthoud pass in the Rockies (11,300 ft) @ 10pm so as to avoid the heat induced vapor lock I'd had the day before in Denver. When I opened the rear hatch, pulled off the cover those thermal reactors a.k.a air injected headers were cherry red. So I cut the air pump belt, let it cool down and everything was fine for the rest of the trip. Except for the stuff that melted like the parking brake cable liner. It also bubbled the paint on the LHM reservoir. But after that air pump was gone there were no more terrible heating issues. But I also wasn't trying to do sustained high speeds like 120-130 mph the rest of the way home. Once I got them off, a few months later, I could see they had cracked open again and I put a set of the MIE plain steel european headers on the car. I didn't notice a terrific change in performance just driving around at speeds up to 100. Maserati continued it's horribly designed pollution control engineering well into the 1980's. To be fair, a lot of manufacturers were struggling with it back then and since Maserati was always at least 5 years behind on technology in early 1980's until right up to 2000 it was a much bigger struggle for them. FI got them out of the high temperature and car fire scenarios. Then they abruptly left the US market. But plenty of QPIIIs and Biturbos burned up. The catalytic converters caught fire because of the air injection and the manual choke. At least with the bumpers they actually worked and didn't cause the car to catch on fire! LOL. A lot of European exotics had ugly ass bumpers for a while. Countach anyone?
Forgive this question from a non-knower. Can someone explain the term "thermal reactor" please. The last post (thank you) hinted.. but my googling results are never quite consistent. How does an air pump for example cause a reaction other than diluting exhaust with outside air? I can perhaps appreciate there may be a back pressure of air.. and therefore perhaps some flow issues...but "reactor"? Thank you for the concept or simply an applicable link (for a K owner). fwiw. My pump is removed and stored well in a box. To align with the above post, my early K has never had an overheating issue or obvious indicator...but I have also only driven over 100mph a handful of times for a minute or two. I have been stuck in bumper to bumper stopped traffic.. with no issues either.. although what a waste of fuel! Richard
https://ww2.arb.ca.gov/sites/default/files/classic//msprog/onroad/cert/pcldtmdv/1977/maserati_pc_a0780004_4d93_ta0.pdf http://carspector.com/dictionary/T/thermal-reactor/ Removed from K.1218:
On engines, such as the Maserati V8 with four thirsty Webers carbs, a portion of the fuel that goes into the cylinders goes out to the exhaust unburned. In order to reduce the amount of unburned fuel (pollutant) that goes into the environment these gases are subjected to a secondary "burning". That is the role of the thermal reactor and it is achieved by mixing fresh air with the already hot exhaust gases, which causes the secondary burn. This secondary burn causes the thermal reactor to become very hot. Eliminating the fresh air by disconnecting the air pump and plugging the air inlets effectively stops the secondary burning inside the reactors and will eliminate most of the overheating issues. Reactors are more restrictive than standard manifolds therefore the engine cannot breath as well. This translates to a loss of power and possible overheating at sustained higher speeds. Depending on how the car is used switching to a standard manifold can be very noticeable or barely noticeable. My Khamsin still has the thermal reactors and the air pump has been removed and the air inlets plugged. I will see how the car behaves during the very hot Georgia summer and decide if I should invest on euro manifolds. Ivan
Wow.Boralogist and Ivan... You just opened my eyes. Thank you.. Those were the best reads and use of my time in a while for interest and value..let alone others I am sure... Bookmarked and archived.. So. Greener is the goal, using science facts.. I wonder, has anyone fitted a catalytic converter while replacing things? Obviously flow can be a concern, but take one way and add another.. Maybe not so bad in the end? Any issues to foresee? I have yet to do anything on my exhaust (other than a bad joint I had repaired) as it works well but will need attention in a year or two. So greening, as best I can is of interest along the path. Thank you again for keeping this spot a never ending support and education destination!
The only thing Green about regulations then, as it is today is the extraction of money from your wallet.
Surprise: PS---Please spare us the negative reaction to all things Maserati, at least for those models you have never owned and don't have a clue about... Warm regards.
The net is full of silly videos usually made by teenagers enamored with Lambroschini Mayuras and Contacts...or whatever they are called;-) which look hoohaahoo but are in actual fact not at all as user friendly in real world pan European fast travel. Off topic here anyway. The two K's shown are Rolf S of Bad Godesberg, Germany in 394 backing up during an International meet in Modena and the owner of 130 doing an acceleration contest in Tehran.
I don't disagree at all! However, any positive publicity for our cars, whether it comes from supercar blondie or another clueless source is very welcome in my book. Just my 1.9 cents!
Today #1284 joined the ranks of converted USA cars. Ivan Image Unavailable, Please Login Image Unavailable, Please Login Image Unavailable, Please Login
You should swap the number plates Joe Here my ex in 2004. The number plate later vanished after I sold it alas but I will have a repro done as a keepsake eventually. Image Unavailable, Please Login
Marc, Khamsin #1226 is registered as a Classic/Antique in PA. Until recently you could not have a “Personalized” plate on a Classic/Antique vehicle. I’ve owned the Khamsin plate for over 30 years, but it needs to be active or you could lose it if it goes 5 years unregistered. So I put it on the GranSport, I will eventually transfer it back to #1226 now that it’s permitted. I also own the Ghibli and Islero plates for PA.
Hello Richard, No no one has had the bizarre idea of fitting a cat conv to a K except you;-), you have a Euro spec car so you should have Euro headers, just let her breathe
Guilty as charged of over thinking Marc. If only I could monetize this well honed "attribute". It has been hard to market this specialized service this far. I do have Euro headers indeed and I believe it breathes sufficiently. Ask my neighbours on a Sunday morning
Khamsin #132 is in the advert below, this advert was in T&CC August 1995, page 171. Image Unavailable, Please Login