Question for the Pros: Running a welded differential or a spool instead of a

[Cavi Mike]

Who is running a welded differential or a spool instead of a limited slip?

[Bebop]

vaughn ran a welded dif on his street S13 at one point

[OldSkool510]

Hey Cavi - Did you ever get your money from the Drift Avengers? lol

[Cavi Mike]

hahaha of course not

[courantcom]

The Braille Battery cars last year both had permanently locked differentials in them. Henry Schelly's S13 had a Miller locker as well. I think Henry actually preferred it to be honest with you... to each is their own! I just know these things because when I have to push them around I can tell. ;-)

[golden eye]

I did run a cusco 1.5 then it broke. 3 years of abuse @ 500hp to the wheels in my R33. Installed a nismo pro 2 way and did not like it. I switched it back to a cusco 1.5 again because snapping back was gone and the car transitioned better coming off the high back at full throttle at irwindale.

[AlexPfeiffer]

I like 1.5 way for single runs, but rather have a 2 way or welded for tandom.

[Justin Banner]

I like 1.5 way for single runs, but rather have a 2 way or welded for tandom.

Ok, time to pick your brain. Why would you run a 2-way/welded for tandom? Do you do a switch at events or just run one differential?

[golden eye]

The 2 way and welded diff pretty much feel the same. It all comes down to personal perferance. Also the other factor is the car weight and the amount of torque your engine puts out.

[socalwrench]

I'm glad this question got asked because I was thinking of the exact same thing. For a full competition drift car- why would you need any differential action? I mean, both tires are slipping the entire run.

[Cavi Mike]

That's exactly why I asked because there's always some random kid that's like "OMG weld is 4 for fa gs u gtta run 2way" and it pisses me off. I knew for a fact some pros prefer a spool but I just wanted it in writing so I could show them that it's driver preference.

[ASD Team]

Just my opinion, but...

There are a lot of factors that change how a chassis performs with either a spool or a 1.5 way or similar. Like most "compromises" in chassis set up, other factors can mask or expose a welded / spool set-up.

1. Wheel speed vs. vehicle speed: A higher percentage of difference in wheel speed vs. vehicle speed will mask much of the negative characteristics of a spool. But as wheel speed percentage of difference is reduced (roll off the throttle and reduce angle as you close in on a slower car while following in tandem) the chassis is more likely to understeer (or tighten up) with a spool as the coefficient of friction increases at the tires. This will be noticed most when you initially get back on throttle until wheel speed increases again.

2. Angle: Shallower angle will also be more likely to induce understeer (or a tightening condition) with a spool. I know we're all trying to run big angle, but whenever you change direction you drive through a shallow angle condition. A spool requires a more committed driver on throttle in comparison when transitioning, or the car will tighten up. All well and fine for the guys with big cahones until they're following someone closely and can't stay on throttle. As angle is increased under throttle, the spool has a much lesser negative effect.

3. Driving style: Drivers who are heavy with their right foot can usually adapt to a spool type differential better than drivers who roll in and out of the throttle more often. Drivers who roll in and out of the throttle more often lose the wheel speed percentage difference more often, and find the car getting tighter as described above.

4. Engine torque: A car with an engine that produces higher midrange torque numbers can "drive through" the tighter condition described above in a shorter period of time, because the engine is capable of producing an increase in wheelspeed in a shorter period of time. The higher torque engine can also run a taller overall gear ratio and consequent wheel speeds at the same vehicle speed, also helping to mask the tight tendency of a spool.

Many people have success with spool or welded differentials, but with all other variables the same it usually requires a stiffer rear wheel rate (stiffer rear anti-roll bar or springs for example) to overcome the tight tendencies described above. The downside of an increased wheel rate compared to what could be run with a 1.5 way or similar is a looser car at higher angle, and consequently a slower drift car.

Like I said, just my opinion But if this helps any of the guys running local events to get their cars sorted, then any subsequent flaming will be well worth it.
And no, I'm not willing to tell you all what diff I'm running in JR's, Tyler's, or D-Mac's cars...

The very nature of motorsport requires that there will be some people who will surely disagree with my comments. So I suggest to anyone that they gather as much information and opinions as possible, and figure out for themselves what makes the most logical sense.


Ian Stewart.
ASD Inc.

[Justin Banner]

3. Driving style: Drivers who are heavy with their right foot can usually adapt to a spool type differential better than drivers who roll in and out of the throttle more often. Drivers who roll in and out of the throttle more often lose the wheel speed percentage difference more often, and find the car getting tighter as described above.

4. Engine torque: A car with an engine that produces higher midrange torque numbers can "drive through" the tighter condition described above in a shorter period of time, because the engine is capable of producing an increase in wheelspeed in a shorter period of time. The higher torque engine can also run a taller overall gear ratio and consequent wheel speeds at the same vehicle speed, also helping to mask the tight tendency of a spool.

Ian Stewart.
ASD Inc.

Sounds like when I go and put the V8 in my pickup, welded or spooled is for me!

[a2low240]

I was running a spool in Long Beach and then took it out in trade for a 1.5 way for the rest of the year. With the 1.5 way I noticed that you can accelerate much faster in drift than you can with a 2 way or spool. This is especially helpful in staying on someones door.

[brainfood]

I have always had a 2-way but plan on running a 1.5 way when I get my KAAZ rebuilt. I also have a welded so I can compare the 2 and see which one I like.