Viscous LS vs. Clutch-type LS for '97 240SX??

[Banzai240]

Has anyone raced using the Viscous type R200V in their 240SX?? I have two diffs, one with 4.37's and the other with 4.08's. The 4.37 diff has a clutch-type carrier, which I used at my last race in Seattle (needed 4.08's!). I'm putting in the 4.08's for an upcoming non-chichane race at Portland, but I think the LS unit is the Viscous type.
Any Pros or Cons of either??

[GJB]

Okay, this should be in another thread, so sue me, but it's still a Nissan thing....

Banzai, how are things going with your car? And how are others doing around the country? Anyone? I hope to see some S14's and DOHC S13's doing well in ITS. Who knows...my current ('97) daily driver and autocrosser could become an ITS car someday in the distant future....if I don't have to sacrifice it for tow vehicle/trailer for the S13.

Greg Brown
S13 ITA under destruction

[Banzai240]

Greg,
I'll have to answer that after the weekend of July 5-7th... I've only raced this thing once since owning it, and that was last October at Seattle International. It's fast, and I think I'd have had something for the faster ITS cars if I could have found the "sack" that weekend, but I hadn't driven a racecar in about 7 years, so it took me some time to get back into it. Also, I'm racing in the RS class, not ITS, which doesn't really make a difference since the only thing not the same on my car is the compression (12:1 vs. stock).

I'll be racing in RS July 5-7th at Portland, and I'm feeling a little more confident, so if all goes well, I'll let you know how it turns out. If you REALLY want to see one of these things fly, check out Joe Harlan at Portland that same weekend... He has the sister car to mine, and he's got it pretty dialed, from what I hear...

Good luck!
Darin Jordan
SCCA #273080
'97 240SX - Radial Sedan

[ITA240]

way off target now....explain this "radial sedan" thing to me..it sounds interesting....

P.S. NIsmo ltd slip in mine...no problems .works great...am looking for stock ltd slip with stock gear for daytona though...anyone have one...

[email protected]

[Banzai240]

Originally posted by ITA240:
way off target now....explain this "radial sedan" thing to me..it sounds interesting....

Probably easier to just link you to the rules, which can be found on the Oregon Region website.

http://www.oregonscca.com/roadrace/2002/Re...lSedan_2002.pdf

Basically, it's similiar to a World Challenge format, except that it accomodates MANY years of cars. One messed up thing about it is the weight factoring for the cars, which is based on displacement and the number of valves an engine has (rotaries have a seperate factoring)... For my S14 (4-valve), the rules require that I weigh 1.1lbs per cc + 180lbs, which equates to about 2820lbs. Hard to compete with Acura Integras and the like at that weight. The penalty for multi-valves is abnornally steep, however, and they are looking into stabilizing the class rules to be more balanced.

If the SCCA really wants to get in the game, they'd institute a true World Challenge format for Club racing, but that may be a ways off, so for now, this is the next best thing!

I'll post some pics after the July 5-7th Regional race at Portland so you can better see what it's all about!

Good luck, and thanks for the info on the diff... My 4.37s have the Nismo racing diff, but my 4.08s have a Viscous type. We'll have to see how it will work...


[This message has been edited by Banzai240 (edited June 26, 2002).]

[This message has been edited by Banzai240 (edited June 26, 2002).]

[murphyd]

Darin, Let us know how the diff works. I have heard that the fluid heats up and causes the diff to act like a welded unit. I hope it works for you because I hope to try the same thing. Have you guys done any testing with headers and exhuast systems? I'm looking for some parts that you may have. You can email me offline if you would like and give me your email address. Keep an eye on my webpage for updates on our car. It goes to the paint shop this weekend!!

[Banzai240]

I'll let you know how things work. I haven't done much driving this thing, let alone testing anything. There doesn't seem to be much available on the aftermarket for headers, so I'm going to fabricate my own.

[ITA240]

Try Loren Barnes at S&S headers. Nice, 4 into 1 header, good fit, good flanges, but not too heavy. I think their standard header used to be the one that NISMO sold. He also builds them with merge collectors if you are interested. very reasonable. The header with a merge collector was not much more than just the merge collector from Burns.
He was very honest to do business with and shipped the item BEFORE it was promised...(not harbor freight here)

623.827.9000
www.ssheaders.com

Jim

[Banzai240]

THANK YOU! I've been looking for this information for some time, as my car still runs the original exhaust manifold... Which, incidently, doesn't seem to lose anything to a "HotShot" header equiped 240SX with an otherwise identical setup...

Thanks again for the information!

[handfulz28]

hey guys, hope I can hi-jack the thread a little. I was about to post a seperate topic on the 240sx exhaust, but since you're already there....
I just measured the Hotshot header for our ITA/SOHC 240 last night, 2"OD at the collector, can you believe that?!?! No wonder it won't show gains over stock.
Anyways, just wondering what everyone else is running for exhaust and muffler. We were using the Hotshot into 2.5"OD, through a resonator, and then through a Dynomax muffler[6" round, 16" long with 2.5"OD inlet/exit]; as you can imagine, we never got a complaint from the neighbors.
So now I'm thinking of sticking with 2.5" pipe, but only going through a Dynomax "bullet" [4" round, 16" long, 2.5" or 3" inlet/exit].
Obviously, we've got to shop for a better header. I think Stretch ran 3" pipe, no muffler just a turndown, with Rebello's "custom" header. Our motor isn't quite that worked, so I don't think we'll benefit from 3" pipe.
Thanks for letting me tag along. If nobody responds, I'll just start a new thread.
Michael

[Tristan Smith]

I run a custom header based on the old Firehawk Series cars' (propably Nismo based) header with 3" exhaust. The problem I had was getting below the 103db sound levels. I think I reconfigured the exhaust three times. Finally, I come out the back of the car and have a Flowmaster muffler on it. Now in the high 90's dbs. These big bore four bangers make a lot of noise. Something to keep in mind as you build up your exhaust systems.

Tristan Smith
ITA Nissan 240sx #56

Oh, and as far as VLSD is concerned, run it if you have it, but the heat generated in racing conditions will break down the Silicon, and eventually it will be no better than an open diff. That leaves the option of either welding it up (I wouldn't), or a lovely expensive Nismo or Quaife LSD. Eventually you will propably have to spring for one.


[This message has been edited by Tristan Smith (edited July 03, 2002).]

[ITA240]

There are a couple different theories to what work best for exhaust system design. One is a slightly modified "bigger is better".

Another is that velocity is better to work with than the volume. Exhaust pulses do not stack in a four cuylinder header like they do in half of a V-8 header. Since the pulses are evenly spaced, if you can keep the eshaust velocity high, you do not need a large collector. With a merge style collector, you would taper down to about 20-25% larger than the primary tubes, then open it slightly to allow for a venturi affect to be created, then route the exhaust behind that. Of course this is all theory..Then, you tune the exhaust by adjusting the length of the small (2" in this case) section of the header and the diameter of the exhaust pipe behind it.

i know this sounds very different from what we are all used to seeing, but remember, alot of the old headers designs were modeled affter half of a V-8 header, and our four cylinder engines have different exhaust problems than an american V-8 does. (refer to S&S headers web page for more on exhaust theory, stacking of exhaust pulses and tuning)

I'm not saying which theory is right, or is better. I'm going to do some dyno time with a couple of headers and 5 or so different exhaust setups and try to find out.

When I get done, I'll share the results..(or maybe start selling 240 exhaust systems..lol)

Jim

[murphyd]

Hey guys what about pipe length, bends, muffler types, etc...
Also, is there anyone around who does the computer mods besides Jim Wolf? I heard that Auto Authority in Fairfax Va did the mods but I 've been unable to locate them

[Tristan Smith]

To get the proper pipe length you need to dyno motor and tune. Otherwise it's a bit of a guess depending on all the factors such as header length, pipe diameter, type of muffler, if any, ect. If there is a formula I don't know it. But there are much smarter minds on this topic out there. So pipe up.
As far as bends go, you can have a muffler shop do it on there pipe benders, or you can buy mandrel bent pipe and cut and weld. The mandrel bend is the best choice but more expensive and time and tool intensive.

Tristan Smith
ITA Nissan 240sx #56

[handfulz28]

thanks for responding. I went and read some of the stuff on S&S' website, pretty good info. Hotshot's header is probably a decent design for a completely stock head. But if you change the flow characteristics, that's where dyno time/custom header is most valuable.
Murphyd: I don't think Autothority does the Nissan ECUs anymore. I spent over 30 minutes with one of the guys at JWT [a real tech/programmer, not the sales guys], and he shared more knowledge about Nissan ECUs than I could ever care about. $600 is a lot, especially if you're only looking to remove the speed limiter, but there's a lot they can do, even if your motor isn't "fully built", to keep the ECU from robbing you of power under certain conditions.
Thanks for sharing,
Michael