1998 550 Maranello "sorting" thread--DIY

There are donut gaskets in the system, but not back at the muffler cans.

The donuts are located between the headers and the cats.

Item 4, P/N 154981 in this diagram:

https://www.ricambiamerica.com/media/catalog/category/550_22.jpg

Pete, what are you driving these days, buddy?

 

You can normally re-use the gaskets. No need to remove the rear bumper, though you may have to tweak the heat shields a bit to get the old mufflers out. The Tubis are much smaller so they go in like buttah. Like mentioned above, plug the vacuum lines and tie them up out of the way.

Edit - now that I think about it, there are no gaskets at the back of the cans. There *are* gaskets under the exhaust tips that can normally be reused if you decide unbolt the tips for some reason. And in fact, I may have done just that trying to remove the old mufflers.

 

Well we swapped the OME exhaust for the Tubis. Much as you guys suggested this was not a big deal;
1. Remove the rear panel
2. We loosened the bolts to the exhaust pipes, then just 'cracked' the bolts that attached to the hangers.
3. The factory exhaust are HEAVY so we supported them with pieces of 4x4s and shims
4. Rather than removing the back bumper we loosened the back panel of the wheel well liners to give some room to get the stock exhaust out.
5. We plugged the vacuum hoses with machine screws (golf tees would work just fine) clamped them off with the hose clamps, then jip tied up out of the way.
6. Bolting up the Tubis was straight forward - they are much lighter than the OMEs. Biggest issue was getting the positioning correct in the space provided in the bumper - 1 person held them in place while the other tighten them up.

Now the important item - how did it sound - wow. Virtually a different car, it has gone from very fast capable GT to a multi personality car. First it starts with a bark that will get attention, then settles into 1k +/- rpms. After that its all about where the revs are; between 2200 & 2800 it sounds docile similar to OME, the higher you go the more it sounds like it is ready for a track day. At 2200 - 2800 I'll have no problem with the Police, at the high rev range I'll have to be careful.

All that said I do have a question for you guys, given I've reduced back pressure are there any implications on the engine or does the ECU compensate?

 

Others have put on aftermarket exhausts, including Tubis, without any apparent problems, although I calculated the injector capacity one time and IIRC there's not much "headroom" with them for increased HP.

If you're concerned, you can monitor the precat O2 sensor values and the short term fuel trim values and/or pull the plugs and see if they're normal (golden) or lean (white).

 

Ok since several of you are 550/Ferrari experts I have a few storage questions; I'm in Minnesota so the snow & salt will soon fly thus the toys get put away.
The 550 will sit in the garage for 5 months +/-.
Given Pete did all the fluids 5 months ago, I'll wait until next summer for that.
I plan on stabilizing the gas (full tank ethanol free gas), question Stab-Il or Sea Foam - I've used Stab-Il on the Porsches for years with no problem.
Second question; do I start the car, I've had 3 different recommendations;
1.Start and shut off as soon as oil pressure is up.
2. If I start it get it up to operating temp before shutting off.
3. Don't start it until I'm ready to car for a ride
Battery tender will be on and I'll push it back & forth every few weeks to prevent/reduce tire flat spots.
Am I missing anything?
Thanks

 

I leave mine for a similar length of time in an Aberdeenshire winter.
- I use fuel stabiliser in a full tank
- Don't start it until you're going to use it - for 5 months it'll be fine to leave it on trickle charge
- Tyres inflated to 45psi and put on 'tyre trainers' to stop them getting flat spots

Sent from my SM-G950F using Tapatalk

 

When I put my cars away for winter, I brim the fuel tank, add Stabil to the fuel (before filling the fuel in so it mixes nicely), clean the car inside and out, inflate the tires to 50psi and either disconnect the battery or put a maintainer on it and just leave the car sit without touching it until the first drive of spring. Has always worked fine for my Ferraris and my Triumphs for decades. I never start them to just let them warm up unless I were to get one out for a drive of an hour or more if the roads are clear of salt but generally I just wait till spring and they stay out of sight out of mind till April 1. My DD is a Quattroporte so I find it scratches the exotic itch through winter well enough that I don't even mind the Ferrari being laid up.


Sent from my iPhone using FerrariChat

 

Thanks all for your input - I hadn't thought about the belts, it will be interesting to see what the "real" mechanics think

 

I wouldn't worry about the belts sitting for the winter - how long have they sat on some of the low mileage garage queens?

For 5 months or so they'll be fine, they're changed well before they're life expired anyway

Sent from my SM-G950F using Tapatalk

 

Ok, now that Spring isn't too far away I have a exhaust question; my 550 now has Tubi's (first generation) and I believe Bradan straight pipes - and it is too loud.
The ideal sound I'm looking for is something similar to the 275s or the 365s. Any thoughts on how or if I can get there?
Thanks

 

An X-pipe or Fabio's H pipe will tone down the sound. If you want the real F1 sound, you need Fabio's 6-1 headers.

 

I put the stock resonator back on after I tried straight through pipes. I have a loud Stebro exhaust. Went from 90+ dB interior noise with straight pipes to about 78 dB with the resonator. That's about 1/2 as loud. Consider: loud music in a bar is about 95 dB.

 

How does that 78dB compare to the stock exhaust system?

 

Hi,

I guess those are not measured values or are they? The decibel scale is logarithmic, so the power difference between 80 dB and 90 dB is not twice as loud, or 1/2 as loud, it is ten times louder! So a difference between 78 dB (safe) and 90 dB would be HUGE, the higher value actually being also harmful to your ears in the long run. I will again do my best to keep all noises to a minimum on the 456GT, exhaust, wind noise, tire noise etc. so I can again do some tour with it without being exhausted every night.

 

Now that the snow & salt are gone I took the 550 out yesterday for the first time in 4 months. All fine but one problem; the accelerator stuck. Turned out to be mechanical, drivers side where the cable attaches to the throttle body. I just 'fiddled' with it and it snapped back to the closed position. (I had noticed that the gas peddle was pretty stiff before it stuck.) I subsequently drove the car (carefully) with no further problems for about 50 miles, but never depressing the accelerator very far/hard. I now recall the stiff gas peddle (like a very stiff return spring) last summer but not being familiar with the car didn't think much about it.
Ok any thoughts on why and what I should do?
Thanks

 

This is a really important thread on 550 repair.

Pete did a great job sorting his 550 and the integrity of his post should prevail. The last 10 posts at least have nothing to do with Pete's sorting.

I recommend we take other new issues to new posts so the search function can work better for specific issues in the future.

 

I am attempting to replace the two temperature sensors and one temp sender underneath the air intake manifold and I greatly appreciate Moorfan's amazing step by step guide. It has so far helped immensely. I have one question I hope someone can answer. Does anyone know how to take apart the black plastic piece at the center of this picture, at the back of manifold? It appears to be threaded and plastic. Please see pic I have everything else disconnected and don't want to screw up now! Thanks for any help
Image Unavailable, Please Login

 

I mean the black regulator ( i think) at the top of pic that is already disassembled. I think i can get the connection at gold colored nut where your 90 degree screw driver is. Sorry, this is probably simple, i just have knack for getting excited and messing up the easy parts

 

Ok. I think I see what you mean. Thank you. I will try tomorrow. FYI I lost only two of the 24 plenum screws in the engine bay! Hopefully I'll find them when I pull it off