| Author | Message | ||
| Salman Hussain (Arezzo)
New member Username: Arezzo Post Number: 9 Registered: 7-2003 |
You're a Gem Stephen :-) Thank You Regards, SALMAN | ||
| stephen winter (355f)
New member Username: 355f Post Number: 18 Registered: 6-2003 |
no thats ok!! rebuilt ones im sure will be good and ANYTHING other then ferrari manifolds is a huge improvement. I never find e mails are answered here is the tel no of QV ascot +44 (0) 1344622011 for tubi in uk you might try Ajay at scuderia systems (0) 1784434394 | ||
| Salman Hussain (Arezzo)
New member Username: Arezzo Post Number: 8 Registered: 7-2003 |
Jeez Mitch I'm afraid can't help you that one. Abit too technical for me. Maybe in a year or two as I learn more :-) I emailed QV London yesterday night regarding the rebuilt Manifolds (Sorry Stephen). Well lets hope they get back to me. If it doesn't work out then I'll get the Tubi Manifolds I guess (if I can find them) If someone knows of a good source for right and left Tubi Manifolds please do tell me. Thanks Guys you all have been great. Learnt so much and it has helped me considerably. | ||
| Mark Collins (Markcollins)
Member Username: Markcollins Post Number: 305 Registered: 7-2002 |
Salman i also have QV London rebuilt Manifolds on my '96 355 and they are working fine, Art is rightthey do have them rebuilt with a better quality material and importantly they are a fraction of the cost of Originals or Tubi's (around $600 a side last time I asked) Price quoted is exchange so unfortunatley there would be 2 x shipping charges! | ||
| Mitch Alsup (Mitch_alsup)
Member Username: Mitch_alsup Post Number: 929 Registered: 4-2002 |
OK: say we want to or have to put new headers on. Background: Headers allow the engine to breath better by reflecting a negative pulse that helps pull burned gasses from the combustion chamber. This negative pulse is followed by a positive pulse that pushes any fresh mixture (pulled across the combustion chamber by the negative pulse) back into the combustion chamber. The length of the header is tuned to the amount of time it takes the pressure pulse to travel down the header, reflect off the collector, and travel back up the pipe to the exhaust valve; AND reach the still open exhaust valve JUST as the intake valve opens. This pulls fresh mixture into the combustion chamber even before the piston starts downward! The length of the collector is timed so that a positive pulse arrives at the still open (but closing) exhaust valve to push any fresh mixture back into the combustion chamber. So the length of the header is timed to the exhaust valve duration, and the length of the collector is timed to the vlave overlap period.  The second figure shows the resultant pressure waves.  At time '1' the exhaust valve opens and a prussure pulse travels down the header pipe. At time '2' the pressure pulse is partially reflected at the collector. At time '3' the pressure pulse is reflected at the end of the collector. At time '4' the negative pressure pulse arrives at the exhaust valve. At time '5' the positive pulse arrives. Since both reflections overlap in time, and since waves add by superposition, the dotted reflections create the dotted (red) reflection wave that travels up the header pipe. The resultant pressure vave traves through the still open exhaust valve and also through the opening intake valve to draw fresh mixture into the intake while the piston has not begun its downward stroke! The positive pressure termination of this pulse pushes any fresh mixture back into the cylinder and thereby the whole shebang creates a supercharging effect. The pressure pulse travel up the intake pipe and reflects off the velocity stack and this starts the flow of fresh mixture into the chamber. Back to the plot: I have looked at many Ferrari headers. I have yet to find an actual collector in a mid engined Ferrari! There HAS to be latent power in the engine waiting to be released. What I am not knowledgable enough to know is whether the piping on the F355 that couples the header on the left and the header on the right to the central section of the muffler A) acts like a collector, or B) exchanges pressure pulses from side to side to enhance what a typical collector would do. I have been contemplating building a special set of headers for my F355 that has the Cats at the end of a collector without having to neck down the collector to the entrance size of the Cat. It seams to me that simply running into the metal/ceramic matrix that makes the Catalyst would create exactly the kind of reflection that the end of a collector would. Does anyone on this group have anything to shed on this matter?  | ||
| Mechanized Engineering Systems, Inc (Mensi)
New member Username: Mensi Post Number: 1 Registered: 7-2003 |
We've had good positive feedback from people who bought our Tubi manifolds. Unfortunately, the factory does not make them all the time and they're difficult to get. I do not beleive there is a single one available Stateside right now. Eight are on order and the factory goes on a yearly vacation today, so we do not expect to get any before october. | ||
| arthur chambers (Art355)
Intermediate Member Username: Art355 Post Number: 2242 Registered: 6-2001 |
Stephen: The QV headers are not just repaired. They are rebuilt using a thicker guage material. That is an excellent solution) for those cars who are out of warranty (all 1997 and earlier cars). I've had mine for about a year now, with no difficuties. These go away when the cats get blocked, and the manifolds get hot, at least that's what happened to mine. Art | ||
| stephen winter (355f)
New member Username: 355f Post Number: 16 Registered: 6-2003 |
a point I missed!!! no one is going to warranty these rebuilt manifolds. Do you really want the hasstle of all this again? I think just ditch em!! | ||
| stephen winter (355f)
New member Username: 355f Post Number: 15 Registered: 6-2003 |
well as to the rebuilt ones QV in london also do this. They open up the heatshields and rebiuld with better material around the existing product. I looked at this option but came to the conclusion I did want something better and more well designed from the start. The repaired ones seemed to be just putting a band aid on the problem. As to replacing them actually you dont even need to take the oil tank out. Just undo the hose fitting from oil tank and loosen the engine mounts and the just tilt the engine a bit and they will come out! the other side is very easy.It is possible to keep the cats and standard exhaust if you so desire. | ||
| Tom Bakowsky (Tbakowsky)
Member Username: Tbakowsky Post Number: 502 Registered: 9-2002 |
You do not have to remove the engine to replace the manifolds. If Ferrari is telling you they do then they are taking you for a ride!!. I have replaced lots of these manifolds and never once did I have to remove an engine to do it! If you would like I can post the procedure. The right hand side manifold is a bit of a pain as the oil tank has to be removed. | ||
| Salman Hussain (Arezzo)
New member Username: Arezzo Post Number: 7 Registered: 7-2003 |
Wassap people. Thanks for the great responses especially Mr. Winters. That was a great post. I totally agree with you about the steel and plus as you know its really hot down here and that doesn't help either. I saw a manifold yesterday that looked like it was.....I don't know what happened to it but it looked really messed up. It was cracked at several places especially at the points where the pipes bend. Ugly stuff. Saw all of this as I was over at my service center yesterday and my parts had arrived from Italy. Man even the tensioner bearings look beautiful :-) Talking to my Mechanic (His name is Koko short for Krikol. He's Armenian and God Bless him as he is one of the best in Q8 when it comes to Ferraris, Lambos and Masers) he told me: "It is possible to change just the Manifolds to Tubi and leave the original Exhaust system on" So I guess with Steves post and my Mechanic the way forward is the Tubi manifolds. About changing them as they break: If you have standard Ferrari manifolds installed on your babe then this is what I have been advised to do by Koko: "Since we're taking the engine out for the full service (usual..belt, bearings, seals etc) then I think you should have both the manifolds changed to Tubi instead of risking it and getting one installed and what if the left one cracks? Then you'll be back here again and we'll have to take the engine out again. Lets finish it in one go" Now having said that a friend of mine told me about this website in the UK called www.ferrarispares.com belongs to a gentleman called Eddie Walsh. If you follow this link: http://www.ferrarispares.com/355_gtb_gts.html you'll see that he lists reinforced manifolds for 575 pounds each. Thats quite an amazing price and quite a saving if you ask me. Now I emailed Mr. Walsh and told him I am ready to FedEx my Manifolds over and I need to know like whats the gripe? How does he want me to pay and stuff. He never replied. It could be that I told him I'm in Kuwait and he thought I was messing with him or something. If anyone knows about this guy and his reinforced manifolds please do tell before I order the Tubis. If they are as good as he says they are then I'll get the ones he's selling. Thanks Guys and Have a Great Weekend | ||
| Ze Shark (Ze_shark)
New member Username: Ze_shark Post Number: 15 Registered: 7-2003 |
Tks. Anybody else has the same to say about Tubi vs OEM manifolds ? What's the price of a Tubi manifold compared to OEM ? Is it possible to change just the manifold and keep the std cats and mufflers ? Is it possible to change the manifolds 'as they break' and have one cylinder bank with OEM, one with Tubi ? I don't want my car to be any louder than it is, we have strict cops around here and periodic inspections at the DMV-equivalent. | ||
| stephen winter (355f)
New member Username: 355f Post Number: 11 Registered: 6-2003 |
Having had many replaced I have become an expert on manifolds for 355s!! The early cars up to 96 had the airpipes leading into the manifold in a sort of v configuration. Later Ferrari changed to a straight configuration of the air injection pipes. This helped stop the problem of the pipes breaking at the point of entry but it made no difference to failure rates as regards the manifolds them selves. Mine was one of the last 99 cars and all are affected. The problem is that the stainless used is very low grade and where the pipes are bend on the outer part of the bend the metal is very very thin, hence allowing the heat to 'burn through' them. Its a poor quality product and if you replce with oem its a never ending story. Buy Tubi and NEVER have the problem again!! | ||
| dave handa (Davehanda)
Intermediate Member Username: Davehanda Post Number: 1450 Registered: 5-2001 |
could you guys all mention the manufacturing dates of your cars? Just curious if Ferrari ever figured this problem out. I see that Salman's car is a 99... | ||
| Ze Shark (Ze_shark)
New member Username: Ze_shark Post Number: 12 Registered: 7-2003 |
I'd be interested too to know if: - the OEM manifolds shipping now are more robust than the originals - Tubi manifolds are more reliable than OEMs I am having my 2nd manifold replaced because of a minor leak, but it ruins the noise and the performance. Would not want this to be a never ending story ... | ||
| Hans E. Hansen (4re_gt4)
Intermediate Member Username: 4re_gt4 Post Number: 1604 Registered: 4-2002 |
My mechanic has a pair of 'dead' 355 manifolds sitting under his workbench. The entire thing is melted. Imagine that it were made of plastic, and you put it in the oven. It looks like a surreal Salvadore Dali sculpture. No chance of welding them, as they aren't even remotely the correct shape! | ||
| dave handa (Davehanda)
Intermediate Member Username: Davehanda Post Number: 1414 Registered: 5-2001 |
If the Tubi was real loud, they probably removed the cat, that will raise the db's a bunch. I believe there is an exhaust valve that opens above certain rpm's. Some folks stick it in the open position, this will also raise the db's. I was also curious if the later exhaust manifolds (oem replacements) are actually upgraded in some way, or just more of same. I have also heard that welding them usually is not satisfactory.... | ||
| Salman Hussain (Arezzo)
New member Username: Arezzo Post Number: 5 Registered: 7-2003 |
I heard a Tubi exhaust installed on 97 355 and you can hear it literally a mile away. Do you think its supposed to be that loud or there was something wrong with the guys installation? My apologies but if the Tubi is this loud then its too much and I don't want to wake my neighbors up especially since I come home late alot from work. Is there a way that I can get the Tubi's installed but reduce the loudness coefficient? | ||
| stephen winter (355f)
New member Username: 355f Post Number: 7 Registered: 6-2003 |
i replaced my stock manifolds with tubi after oem were repaired once. Tubi is a little larger, much better quality material and they seem to give a nice tuned howl at about 4/5 k revs. no difference in output power imho | ||
| Ulf Modig (Ulf308qv)
Junior Member Username: Ulf308qv Post Number: 83 Registered: 3-2001 |
I believe some guys on the board are using Tubi manifolds. They are supposed to be stronger and will probably give you some HP gain as well. Check with the sponsors of this board. | ||
| Salman Hussain (Arezzo)
New member Username: Arezzo Post Number: 4 Registered: 7-2003 |
Well Guys living in a God forsaken part of the world doesn't help. With temperature soaring to 48C or 120F the manifolds on my babe are bound to crack. So does anyone here know if someone out their in the World makes reinforced OEM manifolds that can withstand this heat and not crack every 6 months??? Would you recommend OEM manifolds on the 355? or its better to stick with the originals? Thanks Guys |