Anyone here have a mileage 355 with original valve guides?

Oh no! Please let's not do this again!

The MYTH of the 2.7 cars (the 95s) is exactly that. A myth.
There is no actual evidence anywhere that they make more power or are faster out of the box.
I'm talking back to back dyno results or acceleration tests etc.
"My mechanic says" or "my mate says" doesn't count, unless they can back it up with numbers.

People who have actually tested these cars say that there is no measurable difference.
Eg. My mechanic (who has been working on Ferraris for more than 25years) says he has never seen a difference on the dyno. Some cars produce slightly more power and some produce slightly less, and there is no pattern when it comes to 95 or later cars. Yes I am aware of the irony of that statement but he is talking about actual observed dyno results. Bradan has said on this site the exact same thing.

Around some tracks, the F1 cars have actually been faster (probably due to faster and more reliable gear changes) and they are all 5.2 cars.

So, can we put this rubbish to rest and stick to the topic?

 

Rick- On-Board Diagnostics II, mandated for all US cars after 1 January 1996. Motronic 5.2 was the first OBD-II injection/ignition system ECU(s) fitted to Ferrari cars. OBD-II does not affect performance at all, it is merely a diagnostic plug-in to determine if any emissions related components are malfunctioning. Motronic 5.2 was designed to a higher emissions standard than 2.5 or 2.7, the other DMEs fitted to F355s. How much this affects performance? Beats me, but it is the Motronic system that determines performance, not OBD-II.

 

My 355 is a 96' GTS model, but manufacture date is July 1995. The intake is the newer 2-1-2. Does this alone mean I have a 5.2 car?

 

Yes, single MAF is 5.2.

 

That's the spirit my friend!

 

if there is NO difference in delivered performance at the rear wheels-why then is the (2) ECUs in the rear quarter panels used in ALL 355 Challenge cras-the same setup used in 1995, std version, USA delivery cars?

If the arm chair experts out there look carefully at the revised intake tracks, the single, as opposed to dual intakes, as well as the differences in exhaust routing, the completely different architecture of the single ECUs bus...the SECONDARY O2 sensor circuits, etc, etc...and this is just the visually obvious queues...

1995 2.7 ECUs utilizes' a 32 pin prom chips with socket-no big deal, burning ecu chips can be done with this computer and a "burner" board(in the box at end of desk)
1996 5.2 and later uses an EEPROM-electronically erasaseable program read only memory FILE-its NOT a hard chip, but programming CODE....

These modifications are/were mandated conformity issues with respect to ongoing and ever restrictive upper limit numbers/revisions as called forth by "The Clean Air Act."
Its an ENGINEERING requirement for selling new cars-period...
if you think the performance is the same, you probably are lacking in a scientific education...
there is NO FREE LUNCH...
if the 96 required severe dropss in limits.. then conformity comes at a performance cost-PERIOD-and this will be a loss in seat of the pants feeling/performance, AS WELL A WELL AS quantfitable and measureable data.

As to dynos-what sort are you talking about? Static load stations which you see in most "hot rodding" shops?
engine cell dynos with water brakes, or
4 wheel load testing with a drivers trace a-la-the "LA-55 FTP driving trace"/(Federal Testing Procedure)-used to lab certify autos for conformity to USEPA directives and code???

 

One reason those ECUs are used in all Challenge cars is no software for the Bosch alarm system and its engine immobilizer, which 5.2 has.

No claimed hp or torque differences between the 95 F355 and the 97 F355 in the OMs, not that that proves anything. Ferrari was pretty lazy updating the OMs.

No clue myself, and no dog in the fight. OBD II had no affect on hp. Newer emissions standards may have.

 

I didn't mean to change the topic, but it's always nice to learn new things. My '96 GTS has 22k miles and I'm pretty sure the valve guides are original. I'm not to worried about them either. The negative stuff is usually exaggerated when it comes to these things.

 

In your previous post you mentioned that the final drive ratio was changed......can you provide some proof to back this up? I've never heard of a "1995" gearbox.......

Just because the engine control is different doesn't mean less (or more) power is available. I've personally dynoed a '95 and my '97 back to back on the exact same dyno and [gasp] mine made 4 more rwhp. I realize there are exceptions but this is my quantifiable data. This was on a Mustang brand 4-wheel chassis dyno running in 2-wheel drive mode, pulls done in 4th gear.

I do not subscribe to the " '95s are Superior" newsletter, sorry.


Rob

 

CHE Precision Inc
2640 Lauery Ct, Suite C
Newbury Park, CA 99320
(805) 499-8885
CHE Precision FLASH Intro
Valve Guides, Seats

Had a long conversation with Claude from CHE and although they also build steel valve guides, they don't recommend them for our Ferraris. They recommend the bronze valve guides they use. He said, often times the manufacturing process of steel valve guides creates a porous mix. He said, "try cutting a steel valve guide in half and you will often see pores." They stock bronze valve guides in various sizes and do have them on the shelves for the 355. They're about $20-25 each.

 

In the 5 years of ownership my engine never had a failure,so i didnt had to do something.

The car has 187.000klm and still runns great. The previous owner dont know what he did but according the car papers no valve guides job, so i guess they are still original!

 

Still waiting for a response from 355s..........

You're basically stating that '95s are gross polluters that make extra power and then the OBDII cars are emissions compliant with less power. '95s have emissions requirements as well, just a different way of testing them. That's all.

 

FWIW, the 95 does have different ratios than a 97 F1 or 98 F1 according to the manuals I have. So, is there a difference between an F1 and a manual? Additionally, fuel consumption (i.e. mpg) is significantly lower for a 95 at a combined cycle of 17.65 mpg (imperial) vs 20.8 for a 97, or 98 F1. Thus, regardless of the published specs, 95 are burning more fuel. Does that equate to more fuel = more HP?

All it take is a little fact checking.

 

My 96 Spider (2.7) now has 54000kms on it's original valve guides.
When I bought it, the cats were defective, so I installed Tubi headers and cat bypass pipes.
After inspection, the oem headers were still ok.

This car puts a smile on my face everytime I take her out. Untill now it has been a very reliable car.

David