Did you notice #31097 is for sale?

Wonder what the story is behind the change to the differential from the automatic? Would reduce revs at highway speeds but at the expense of more sluggish performance while accelerating. Odometer added less than 4,000 miles in last 7 years.

 

Dave,

It seems heavily re-worked cosmetically. Is the sunroof original?

The comment on valves is a bit scary. I read that as either worn guides - needs headss redone or slow to rise oil pressure/low oil pressure - needs the bottom end done.

Otherwise, pretty tastefully done car.

Regards,

Art S.

PS. how does this one compare to the grey one in CA with a noisy tranny?

 

Anybody here familiar with this one?
Is that a factory sunroof? From the angle, can't tell if it's an aftermarket lay-in, and I'm not familiar enough with what the factory one should look like.
I really like the color combination, but it's just never a carb car, never.........

The rest of the description sounds good, though. I'd like to know about that Diff Ratio change, and if the suspension bushings have been done.

 

An earlier ad when the car was for sale in 2002 said that the sunroof was after-market by ASC.

 

I valves mentioned are the cold-start valve(s) that enrichens the fuel mixture for easier starting from cold, not the intake and exhaust valves in the head.

"Cold-start valves are acting up. Hard to find according to my mechanic"

I wouldn't think that the cold start valve is a rare or difficult to find part.

 

Ah, thanks.

 

http://www.400register.com/manuals/general.asp

Gentlemen,
Please find in the Series 2 OM (for instance) on pg.13 for auto trans. & pg. 14 for manual which lists 12/41 (3.25 to 1) & 10/41 (4.10 to 1) crown & pinion ratio (diff. ratio), respectively......all in an effort to achieve the same final drive ratio.
Bruce

 

I wonder if it will go to red-line in 5th Anyone care to do the math and share the result

Regards,

Art S.

PS. Dave, thank you for your insight!

 

Exactly. Seeing as the top speed of the automatic and 5 speed versions were within 1 or 2 mph of each other at about 150 mph, its clear to me that the mismatching of the transmission with a differential from the other type would have a serious change in the performance. Both top speed and responsiveness in the lower gears would be affected.

By moving to the 3.25 from the 4.10 ratio, the car would indeed show lower rpm's at any given road speed and could theoretically have a higher top speed if the car has enough power to reach redline in 5th with the lower ratio. Which I doubt. Even if it did, that would not be a reason to make the change because realistically the number of times where you could safely go more than 150 mph on American roads are very few and far between.

The cost of this is that the responsiveness and quickness of the car at lower rpms and in the lower gears would be reduced quite a bit. This would definitely hurt the performance and fun factor of the car down at the speeds that you would experience every day.

So it's hard to imagine why anyone would change the diff for a questionable gain, if any, in top speed and pay the penalty of less responsiveness and fun in typical driving conditions.

Maybe the original diff was cooked when someone drained the oil for a change and forgot to refill it. Driving with no oil in the diff is about the only way that I can think of to kill one of these because they have a reputation for being a pretty robust piece of equipment.

The car seems pretty honestly described and if he has the service records, good references from a known Ferrari shop as he says and the car passes a PPI, it seems like a decent car. But the differential change probably will knock around $10K off the value as that is what it will likely need to change it back.

 

My mistake Dave, I must of read it too fast & figured that both diff. & tranny were changed (w/all the talk of changing trans. lately).

How about 4.1/3.23 = 1.26 X 150mph= 189mph, does that work?

Maybe he's just a cruiser w/no spirit in him.

How 'bout for better gas mileage? That's huge for a 400, it's gotta count for somethin'!
Could changing just the crown gear be all it takes?
Anyone know if the torque tube is adjustable to except either trans. (not knowing if there's any length diff. between the 2)?

Especially on the East Coast! The Pa. Turnpike isn't bad after a fresh pave.
Out west, there are tons of places (AZ, CA, CO, NM, MT, WO, & I think Texas!). Though I haven't reached redline in 5th, the only difference in the car @ 140 that I could tell was my heart rate, that thing rides like a tank---confidence reassuring. Power begins to roll off above 125 but w/set of ZR's going downhill, it might well be able to pull it off.

 

Changing from a 3.25 to a 4.10 will INCREASE revs significantly, 21% in fact. Off the line performance would be hugely improved.
My slushbox car will pull 6500 in top gear so this would significantly decrease top speed given the same(1:1) top gear ratio. What is the ratio of 5th in a manual box? Overdrive I'd guess.

 

You are exactly correct Ross, but in this case the change went the other way: he replaced the 4.10 ratio that comes with the 5 speed (yes 5th is overdrive at 1:0.795) with the 3.25 rear end ratio that comes with the automatic.

Here are the OVERALL gear ratios including the crown and pinion ratio:

5 speed

1st: 1:12.20
2nd: 1:7.358
3rd: 1:5.394
4th: 1:4.30
5th: 1:3.4178

Automatic

1st: 1:8.4789
2nd: 1:5.0618
3rd: 1:3.4166

So you can see how the final drive ratios match up in the respective top gears and that is why the top speeds are so close together.

Who knows what the final combined ratios are with the 5 speed box and the automatic's 3.25 rear end ratio.

 

I wanted to post about this in my prior but didn't want to get mistaken info. out there, refer to the 3 excerpts from the 365, 400, & 400i S1 OMs...

I've seen this described in other publications in the past & also wondered how this could be accomplished w/o a pump, maybe a passive set up.
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Correction......Pinion gear.

 

Dave, I understand that the 365, 400, & 400i Series 1 cars don't have a pump nor a filler neck & reservoir, but the attached pix from my prior post are from the 365, 400, & 400i Series 1 OMs (from left to right) retrieved from the 400register site (as I don't have these laying around here). Ferrari has been printing this since 1974 & I've seen it in other publications as well (outside of the Ferrari syndicate). That's why I interjected the 'passive' thing, no big deal. I clearly don't understand the whole 'possibly passive' operation myself. Just wanted to get it out there for further discussion, it can't believe it is that abstract that we can't figure it out.
Btw, don't these pumps clean up nicely?
Bruce
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Could changing just the crown gear be all it takes?


The ring and pinion gears are a matched set and will need to be changed togeather.
It will be cheaper to just find a used diff.

This looks like a nice sorted car, big plus.
Down side is it has been modified.