Im looking for the best bang for my buck for autox and after looking to boost for awhile I decided I would benefit the most from a LSD, lightened flywheel and upgraded clutch. As great as another 100hp would be, I think the increased traction and faster entry/exit speed would be very helpful and at a fraction of the cost… and would only enhance a turbo if I decided that down the road.
The OBX LSD is everywhere with very mixed reviews. Have they gotten any better over the years? There doesnt seem to be much info in the last 2 or 3 years. With a lifetime warranty I would think it would be in their best interest to build a decent device. Other than that I would like to find a used ITR or splurge on a MFactory.
Any advice/experience? Must eliminate the one-tire-fire!!!
It would make better sense to go keep your stock flywheel unless you’re builder recommends a upgrade. Even a type r flywheel is pushing it on a oem engine. My buddy ran a 240 hp b20v on the itr flywheel.
As for lsd you want to make sure you get the 92 93 ys1 trans to drop your lsd. It will just take more than the 90 91 s1 y1.
Lsd I would go phantom grip it’s cheap and very effective.
Mfactory or quaife.
Could you elaborate on the difference in durability of the 90/91 vs 92/93 trans?
Also, reducing flywheel weight on a n/a car has produced great results from my findings. Reducing rotating mass and increasing acceleration. Its a no-brainer imo. Ive always been told with boost a lightened flywheel isnt the best though… not my goal now though.
Those phantom grip thingies look sketchy too. Haha
light flywheel is not as beneficial as people think, works great on time attack and road course when you are always in high rpms. but for driving, and low rpm stuff the stock is good. its funny when u see people put lightweight flywheel in a car and wonder why they got slower in the 1/4 mile as well. u just lose the weight of it that u need to get the car going…
I’ve heard people argue that before, but I honestly have never agreed with it. The only negative affect I would imagine besides driving comfort suffering due to quicker revs would be when you are decelerating in gear. By reducing that weight you no longer have the additional rotating mass generated from your initial speed to carry you further when you let off the gas. However off the line I can’t imagine any case in which heavier components would be an asset, at least in the case of a flywheel. I don’t know how more weight helps get your car going. You have to generate more power to rotate more weight especially off the line… in that argument heavier wheels would be ideal as well.
Not being a jerk by any means, I would be interested in hearing another side to the equation. However in my case I’m using this for autox so it would be beneficial according to your comments.
I have two Itr lsds one Itr Trans that needs a rebuild and one Gsr Trans with a 4.7 final drive and Itr Lsd. Oem works great!never tried the obx but was interested in that too any one personally have a obx lsd?
My buddy lost torque in his 240hp b20v when he switched to a light flywheel.
The internals in the 91 trans are just weaker never designed to get more than 130 hp. I’m pretty sure it has one fork selecting gears vs the 92 and up has 2 forks…
I had the jdm y1 lsd trans and diff on a jdm 00 spec type r b18c and some bolt ons and tune. I split the lsd taking off from a stop at 3k rpm, only last me 4 months after a full rebuild on the trans. I sourced out a new y1 lsd and it last me 3 weeks.
Bought a wavetrac lsd had issues with it going in the 91 case, I needed to source out a 92 counter shaft. I would just sell it or use as a spare.
I think you on the right track. Personally, I wouldn’t break the bank on the flywheel. Maybe you could do a Type R? LSD and clutch are two of the best mods I ever did. I cannot tell you how much better autocross/road racing is with an LSD. It’s a night and day difference. Don’t bother getting an OBX. I don’t know if you are planning to do the install yourself or pay someone. Either way it’s too much of an investment of time or money to take everything apart to put in some piece of crap. I have an mfactory LSD and I can vouch for the quality being top notch.
+1 for an LSD. It’s one of those things that isn’t easy to “bolt on” so most people skip it in favor of things that won’t make a difference like colorful LCA’s and Beaks subframe bars. Open diff was terrible on track and it was a HUGE improvement when I upgraded to an OEM ITR unit. And from what I’ve heard the more advanced aftermarket ones are even a big upgrade from the OEM LSD.
I’ve heard good things about the OBX if you know what you’re doing with the install. From what I read the issues are primarily from installation error or not checking to make sure tolerances and such are good. IIRC it’s a Quaife copy, nearly identically and that’s a quality diff. I’d agree with jdecks, with all the labor (and possibly $$) it takes to install a diff I wouldn’t bother going cheap. Personally I HATE pulling the transmission so I’d do anything possible to ensure I don’t have to pull it out again.
From overhearing track buddies talk here’s what I’ve gathered:
OEM < Quaife < MFactory < OS Giken
(apparently the OS Giken is amazing)
As for flywheels I originally lightened an OEM flywheel down to 13lbs (basically same as an ITR) and that was fine, later changed to a 9.5lb Exedy which was also fine. I personally don’t think it’s difficult to drive and actually the pedal pressure is worse than the flywheel weight. I’m becoming an old man, so for me if it was a street/daily car I’d run an OE replacement clutch and OEM or 13-14lb flywheel. For a track car a mild upgrade above the stock clutch paired with a ~9-13lb flywheel should suffice and I doubt there’s much of a benefit from getting more extreme than that.
A few years ago I got my hands on a short gear YS1, and I used an 9.5lb flywheel with a full face organic clutch. The clutch required a bit more force, but still has plenty of range in engagement. The flywheel is fine and obviously reducing inertia will be a benefit. I wanted to do a Quaife; however, if I was to split the case then I would have wanted to do seals and sycros, so I waited on that. The ys1 uses the same gear sets as new hydro b-series transmissions, so I see the obvious benefit of parts available for replacement as well as customization if desired. The diffs and final drives across all of the b-series are interchangeable if I remember right as well as flywheels obviously.