Have you noticed improvement with the chip and intake? I put a Challenge muffler on my 98 berlinetta-good weight reduction and sound but still teriffic heat. Sometimes the rear fenders are too hot to hold your hand against them. This must be really bad for the components in the engine compartment. I have stock headers, the fourth on the passenger side and second on the driver's side and am convinced that unless a new design is developed they will contine to burn out. If anyone has noticed significant improvemnt in heat reduction with other cats or by any other means, I would love to know about it.
The Hyper-Flows really cut down on the heat. With the GruppeM I insulated the underside of their heatshield and the air box is slightly warm to the touch even after a real hard ride ,whereas the stock box was too hot to even touch.
Merdav, your welcome like to try help if i can. The Hyper-Flow cats are great and went on very easy they look fantastic also. Only thing i would say is with the tubi and cats it gets very hot so i put on a challange rear grill. good luck hope it works out for you.
Well I couldn't have picked a hotter day, I'm in the garage now. So far 1 hour in and doesn't seems like much progress yet, put on some shorts and heading back, I'll keep u up to date.
Take your headers out and have them ceramic coated, inside and out. You'll be amazed at the heat reduction. Does the 355 have heat sheilds like the earlier car? If so, take those off in addition to ceramic coating the headers.
Well I would say about 3 sweaty sticky hours for the install. The only part I'm not happy about is the sideways pressure on the exhaust bypass valve housing. I actually had to use a prybar against the side of the muffler to get the 2 bolts back in. The cats couldn't be adjusted to relieve the pressure, so tommorrow I'm going to remove the spring loaded bolts from the bypass tube to the headers, replace the exhaust doughnuts, and try to reseat it. To be continued.... P.S. I only road tested arount the neighborhood, but so far the Hyper-flows pretty much sounded like the factory cats, maybe a little throatyier.
Did you remove the rear bumper and muffler, or just bend the muffler back a little? I just helped someone install a cat on a 355 and I had to hammer the doughnuts on after we heated it up. thanks, --tony
Tony I loosend up all the muffler bolts and pushed down on the tailpipes, cleared it well out of the way.
Just went through the same deal with my Tubi and test pipes. Not rocket science but a bit of a knuckle scrather. Hey, have you priced out those donuts??? Ouch!!
Does anyone have any experience with the max-flo cats ?? Being the price is MUCH lower .I am definatly going to change the cats BUT dont want to spend more than i need to. I appreciate ANY input. Bill MY355
When I got my Hyperflows it came with a set of doughnuts for them. Last night I removed the throttle by-pass tube. The doughnuts on it are different the the cats. 1st I bolted the part where the by-pass valve is installed, when I get home today I will bolt up the part where it meets the headers evenly hopefully taking of the sideways pressure from the by pass. The flanges from the headers to the bypass tubes on the left & right actually had different flanges hence different doughnuts, so I am going to reuse them rather than try to figure out which ones are right. What does the factory do, just keep sticking on what ever parts fit until they can get things to work? Alot of things on these cars are not very uniformed.
The people at Max flow are hard to get in contact with, from what I've "heard" they use universal cats and they just weld on the appropriate flanges for each car. I went with the Hyperflows and got a good deal from RPM Racing in Huntington NY. Troy at Hyperflow will also give you all the install tech support you need.
More important than all this "replace the cats" stuff which most people do to relieve back pressure and increase slight HP. I believe the more critical part of the 355 exhaust is the bypass which open above 4000 RPM's. When I removed my bypass tube last night I noticed it has similar packing inside like the cats do. This is where the exhaust is filtered to it higher RPM, so wouldn't it be more important to upgrade this tube to one with no honeycombs in it for better high RPM sound and performance? Hyperflow tells me this will be thier next project manufacturing real "freeflow" bypass tubes.-MICHAEL
Just had the driver side one go out. Had it re-built in about one hour by Miller Catalyzer in San Diego. Way cheaper than stock. I let them quote you a price. They are a bit whimsical, but it's definitely under $1000. All the best, jim Knapp
Hi guys. You are just the people I need to talk to. I've got a 98 355GTS and my cats have just gone. Like you I'm trying to figure out which way to go. OEM or another manufacturer. Unfortunatley in OZ there is very little info about other manufacturers. I've seen Hyper Flow's web site and read your comments. However in discussing it with the local Ferrari mechanic (trained in Italy at Ferrari) he says you have to get the right ones. Apparently mines a 3 stage unit. Does this apply to the convertors you bought. Do you have the 2 sensors cats? And finally if you don't do anything and run without changing them, whats the bad news , other than EPA issues. Appreciate your comments. Tony
O.K. remove adjust and reinstalled the bypass tube. Exhaust sounds good, look good, feels good, is good . Damn it's 7AM on Saturday morning and I'm going to give it a 200 mile road test. Anybody else want to go with the Hyperflows, I know where you can get them discounted...PM me.
Hello Tony, I spoke to Bruce, in the service shop at Ferrari of San Francisco and he told me to drive my 355. He said that if the cat was making a lot of noise it could clog and cause the manifold to fail. On my cats I have two O2 sensores and a thermocouple. Good luck in the land of OZ --tony
TOny, done, install took about 3 hours, if you are going to do it let me know and we can take by phone I'll give you the tips I wish someone had given me.
Thanks Tony. Thats what my official ferrari mechanic said as well. Reckons nothing would happen except for noise (caused by rattles in the CAT) and the Check Engine light would stay on. Then I've been reading the threads about manifolds cracking and started to wonder..... I spoke to another mechanic here and he says to replace the thermocoupler first. It may have failed and is sending the wrong signal. But this seems a long shot and a waste of cash if its not the prob. Any way to check these?. Any one else had this suggestion. TonyM
