RussinStk

Greetings:

What type of LSD and what was the lock up for 87-91s?

Was the gearing the same for all model years? If not, what was the different gear ratios?

Thanks

Rxmfn7

iTrader: (4)

86-88 models that were equipped with the LSD had a clutch type. The 89-91 LSDs were a viscous coupling LSD. Gearing was determined by the transmission and model. For the most part , all autos were a 3.90:1 ratio while 5-speed manuals had a 4.10:1. I believe there was 1 year for the 'vert that got a 4.1 reguardless of tranny ( 1988 ?). Also there was a special edition in 1989 and '90 dubbed the "GTUs" that recivied a 4.3:1 final drive. Also, keep in mind the turbo and non-turbo rear ends (as well as the rest of the driveline) were different, being the turbo recieved an 8" rear end while the N/A had a 7".

RussinStk

Thanks for the info!

I would assume lock up would be in the 20%range?

RETed

No specs in the LSD lock-up characteristics.
If it's original, it's most likely dead.


-Ted

Icemark

This information is found in the Options and Standard features thread at the top of this section.

Please read that and the FAQ for FC before posting.

RussinStk

I read them....I must be illiterate because I could not find the stats for percentage of lock up.

I did find this:
"Did my FC come with a Limited Slip Differential?
Only the following FCs had a LSD from the factory:
86-88 GXL
87-91 T2
88 GTU
89-90 GTUs (however not the 89-90 GTU)
It is also rumored that a few rare 91 coupes with both the A (upgraded the interior trim, added a power sunroof, tilt steering wheel, cruise control, and 4 piston front disc brakes and vented single piston rear brakes) and the B package (leather seating, a CD player, and rear cargo cover) came with a LSD, but you should note that Mazda denies that any FC other than the T2 came with a LSD in 91). You can also tell by looking at the differential as there will be a LSD tag on S4 cars with a LSD."

A very superficial overview of diffs. Hopefully you are aware there more than one kind of diff. Being new to the Mazda marque; diffs in terms of type, ratio and % of lock up are an important issue for me.

Thanks for those who responded with useful information.
I appreciate it.

flamin-roids

What I don't understand is if you have the effort to scold someone for not searching the FAQ's why not answer their question? Autos had a 3.90 and the 5 speeds and turbos had a 4.10. The GTUs had a 4.30. S4's are clutch pack and the S5's are viscous. Thats about the idea.

Icemark

The lock up offical ratios are probably no longer available anywhere (and any answer from anyone here with a number or precentage is probably guessed or made up), and there are three different types of differentials used in an 2nd gen RX-7, all dependent on year and model. The types are Clutch Type, Viscous, and Torsen types.

(again) As covered in the options and standard features thread, the Clutch type differential was found in the 86-88 GXL (with either 3.9 or 4.1 7" gears) the 88 GTU (with 4.1 7 inch gears) and the 87-88 Turbo (with 4.1, 8 inch gears).

On the 89-91 models, the LSD was a Viscous design (except Infini versions) only found on the 89-90 GTUs (not GTU, but rather GTUs) using a 4.3 7" gear and the 89-91 Turbo using a 4.1 8" gear, and the Infini IV using a Torsen 4.1, 8" differential.

Icemark

Perhaps it is because of the same questions coming up over and over again, for people too lame to search or read the basics (such as the FAQ or the Standard features threads).

Everything but the lock up ratio is already available in those two threads.

and perhaps if you had read the same things suggested, then your answer would be more than half right.

twistedriver

The infinit IV has a torsen LSD?? So i am guessing that they are in T2 diff housing?

Icemark

The S6 FD also used the same 8" Torsen originally found on the Infini IV, but the original poster never asked that.

RETed

Why don't you tell us why you care so much?

If you were a real racer, you wouldn't be messing with stock parts unless we're talking about spec racing.
I believe even SCCA IT-S allows rebuilding of the stock diff, and Mazda Comp / Mazdaspeed offers upgraded discs to chose the lock-up characteristics you want.

Everyone else wants an aftermarket LSD, which is superior over the stock LSD's in almost any way.

So bottom line, the information you're looking for is practically moot.

Oh, if you haven't figured out by now, the stock LSD's are a piece of ****.


-Ted

Icemark

Now, that is what I was gonna say, but couldn't figure a way to say it without sounding even rude'r than I did originally.

RussinStk

As I said, I am new to the Mazda marque. I am in the market for a 2nd Gen TII. I am trying to assess model years, and options to determine if there is a "preferred" model year with advantages over other years. Since I am beginning from scratch and do not know squat about Mazdas, I figure I would ask a few questions from people in the know. It is often easier to ask a person who can give a quick and concise answer then spend 2 hours searching 10 urls for comparison data. It like asking me about the differences between the various versions of the E30M3s: US, Evo IIs, Evo III etc. I could say “go find it yourself”, or spend 5 minutes of my time answering a specific question, that may take someone 1 hour of time to find all the right URLs etc.

I have been auto-xing a BMW E30-M3 for the past 3 seasons (this year I should net my 4 regional title in a row with the car). I am well aware of various diff options for BMWs across model years etc. Diffs in auto-x are obviously very important. I have ran everything from modified stock clutch type diffs with modified ramp angles and increase lock up to my current quaife set up.

Within the SCCA Solo II there are class restrictions which have very specific rules about diffs and gear ratio swaps and modifications. Since I am considering more restrictive classes then street mod with open drive train, the information is important. It is also important to understand the quality of the stock Mazda diff which you mentioned. Depending on the class, my options may be limited to modifying a stock diff to try and obtain the performance specs I need. Opinions like yours are important in deciding SCCA class, and model of year I may purchase.

I asked a very reasonable question, with very specific parameters. I didn’t ask for a dissertation of the general difference between model years. I did read the FAQ and did not find the info I was looking for, so I addressed the forum. I have spoken to Mazda owners and obtain some info. As most know, it great to be able to verify and cross check information. I rarely depend on one source of information, even if it is in a FAQ.

Thanks for your time, but not the attitude.

Russ
SCCA SFR Region – Sacramento
New Competitor Coordinator.

RETed

I guess you should already know that the FC Turbo II is not competitive in SCCA Solo II.
Good luck winning with the car.


-Ted

RussinStk

Take a look under "B Prepared" National results last year or the year before...or the year before that.

Steve O'Bleines has few National Titles to prove it. Btw, his average margin of victory over all cars including fully prepared corvettes...not less than 4-5 seconds!

Last year his co-driver even beat the field by more than a second.

2003 National Solo tour results: http://www.scca.com/_Filelibrary/Fil...oNationals.pdf

The car might also work well in sm2, however I believe the RX7 twins turbo will end up ruling that class. Might need to go up a model year.

Russ
SCCA SFR-Sacramento
New Competitor Coordinator

Rob500

Steve sold that car after nationals last year. If I'm not mistaken, they've added 200 lbs to its min weight this year.


Rob

RussinStk

Steve apprently traded his car for an A-Mod car. I do not think the car has surfaced on a regular basis. Steve is an outstanding driver. IMO, the car will still be able to win at the National level even with the "victory balast."

Russ

Rob500

He's helped me with the development of my car. Co-drove my car at a local event once last year when he broke his. The guy's got 5 seconds on me in my own car right out of the box.

Rob

RETed

Sounds like the old Craig Naeglar[sp?] FC?
I still don't think the car is competitive.
The car is almost 20 years old, and technology is just surpassing it every year.
Double-wishbone is the norm, and the MacPherson + trailing arm suspension on the FC is just archaic.
To spend the money to develop an FC to be top finishing means you either got a lot of money on your hands or just plain stubborn.
The Z06 is the ringer which Corvette developed to just dominate in SCCA.
Almost as bad at when the FD first was released.
Look at what happens when a certain car dominates - it gets handicapped or bumped in class.
I don't consider anything above SP classes to be a proper display of it's performance.
Prep (and Mod) classes starts to become a matter of how much money you have - almost unlimited mods and 10" wide wheels is just plain ridiculous in my book.
Try and get the FC to be competitive in Stock or SP, and you'll look stupid trying to get top in class at the Nats.

I'm not questioning your driving skills.
I question your choice of vehicles.
I'm pretty sure you can choose a more suitable chassis and develop the car a lot faster and easier versus an FC.
If we're talking about Prep or Mod classes, it really doesn't matter what chassis you pick - it's a matter of development, which means time and money.

I've seen, done, and did a lot of research of the FC on SCCA competitive racing, and to me it's a waste of time.


-Ted

RussinStk

Yes, Steve's car was the old ex Naeglar car. I agree with you assessment of the prep and mod classes, as being classes which are money pits. The Mod and street mod classes are probably the worst in terms of sucking your wallet, even more so than prepared.

Your notion about anything above SP does not truly display a cars' true character is also correct. Hard to compare car with which highly modified to it stock counter part. I guess with a enough money and a good machine shop you could make a Yugo a screamer (well maybe not a Yugo). The one advantage of the prep, and Mod classes, is you can find cars which are relatively inexpensive, with great engine potential. You engineer around the suspension handicaps, which is why you need a more open rule set, then SP or stock.

The FC certainly does have limitation in terms of stock and sp classes. However, Tom Ellam (who runs in our chapter) runs an old RX-3. He has numerous National titles in it, against sigificantly more modern Miatas etc. While modern tech is generally better, it what you can get out of the car that really matters.

Part of my intent of my question at the beginning of the thread was to access what potential there is for the FC and where that potential may be unleashed.

Ted, I appreciate your assessment and your opinion of the FC in SCCA. I will certainly add it to the database. Thanks for a excellent post.

Russ

RETed

Oh, that explains a lot...
I'd like to meet that car and bash the crap out of it!
Like it bashes any hopes of any FC turbo owner thinking of doing good in SCCA Solo II.
I remember when the FC turbo used to be in BSP (and B-Stock?), but due to Naeglar's success, got quickly bumped into ASP.
Uh, why are we competing with FD's and Porsche 911's???
I think BSP was the proper class for car looking at current competition, E30 M3 (I think), some Corvettes.

I've been out of SCCA Solo II for years now, so the above info might be incorrect.

Good luck with your future SCCA endeavors...


-Ted

avrfan

I disagree. I had an 1988 SE and I swear that thing had absolutely a burned out clutchpack or those 88SE's actually did not come with and LSD if any sort. I think they call it an "open diff" any ways, compared to the clutchpack 4.1 LSD rearend in my 88GXL I totally could feel the difference when pushing it hard in the rain or even dry when cornering. Way better control and feel especially in terms of left vs right hand turning. Especially for an NA motor. Turbo guys probably have way more power to lay down and could appreciate the difference in lockup ratio etc.

Also, that is a very demeaning to say "if you were a real racer". Thats just without much tact. Maybe its not about being a "real racer" or a "fake racer" or a "wanna - be racer" but more about doing the best that you can with the knowledge, time and money that you can afford. Besides aren't the Torsens considered pretty good? and those are factory.

Dave

Icemark

There are so many misconceptions in that post I don't know were to start

RETed

Sure, if I had the car on the track, it'l be obvious.
Claiming you drive "hard in the rain or even dry when cornering" is dangerous on public roads and just not safe.

PLEASE...the matter was settled several days ago.
I find it "without much tact" to be resurrecting this thread so late when it was already taken care of.
You're pulling my words out of context, and I suggest you REREAD the whole thing before you start posting replies that are moot.


-Ted