The 14b Drag Race Discussion Thread

[91stocker]

OK... You want to talk about rotation? Then, look up moment of inertia and tell me what does a larger shaft diameter does to your effective "weight reduction"?

There are very little net weight savings from the rotation perspective.

Any reports of "feeling the difference" from the mod like this, are what is called a placebo effect.

Arent what your getting at similar to "leverage"?

 

[talontd92tsi]

Seriously! Best wifey ever!

Damn skippy. I guess she took what we were saying in Brian's hotel room at the shootout seriously.

Tell her again shes my savior with the Excedrin

 

[Steve93Talon]

First problem happened when transfer case broke and we couldn’t take the broken shaft stubby out, because DSS yoke had too much twist in it! Wasted day at the track (normally, we would have replaced the t-case and went on).

We've had that happen with a stock driveshaft, so I wouldn't blame it on the DSS yoke necessarily.

 

[91stocker]

Seriously! Best wifey ever!

For sure man, you done good.

 

[rhamlinii]

OK... You want to talk about rotation? Then, look up moment of inertia and tell me what does a larger shaft diameter does to your effective "weight reduction"?

There are very little net weight savings from the rotation perspective.

Any reports of "feeling the difference" from the mod like this, are what is called a placebo effect.

Leon vs. Phil take 97. ACTION


Almost a full decade later and I laugh over you two. Is this the same car you drove not to long ago at the track? Any Updates?

 

[SBstar]

Blah whatever. I'm not really going to worry about what one dude says after reading good things about them for years. A broken t-case caused the first issue and the second was caused by user error, I don't see either of those as real negatives towards it. I'm not a physics guy but to me lighter is still lighter, I highly doubt it's going to hurt performance. Yes, there are alot of other things that would have improved my car better then that for the price but the wife is sick of my driveshaft problems and got it for me, I'm not about to complain.

 

[GRNDSM]

Shane, I wasn't really addressing you, but rather people who are thinking about this mod. I guess it makes a fine gift (something you wouldn't buy for yourself). Congrats on awesome wife!

If someone gave me one, I would do two things: keep an eye on the splines (both of Bruce's splines were twisted, and NOT where Tcase broke). And keep a spare!

Generally speaking, I do not like to upgrade factory parts which work fine as it is. What was the history of your failed driveshafts? I find it that they usually fail after being "rebuild", which is why I suspect that Bruce's second failure was assembly error.

 

[Phil1320]

OK... You want to talk about rotation? Then, look up moment of inertia and tell me what does a larger shaft diameter does to your effective "weight reduction"?

There are very little net weight savings from the rotation perspective.

Any reports of "feeling the difference" from the mod like this, are what is called a placebo effect.

Umm....No thanks. You talk like you are reading out of a Popular Science magazine and what you say is the WORD. You talk like you are the benchmark on all DSM knowlege. I call it

Whelp guess what? All that got your 14b times SMOKED by me twice

So, all you got is your words

blah whatever. I'm not really going to worry about what one dude says after reading good things about them for years. A broken t-case caused the first issue and the second was caused by user error, i don't see either of those as real negatives towards it. I'm not a physics guy but to me lighter is still lighter, i highly doubt it's going to hurt performance. Yes, there are alot of other things that would have improved my car better then that for the price but the wife is sick of my driveshaft problems and got it for me, i'm not about to complain.

WORD...especially that ^ dude...

 

[GRNDSM]

Phil are you really bragging about beating my 6 year old record? I never set my car up for chacing a record, it was break-in turbo! I just noticed that it was a good turbo and took it to the track!

And YOU brought up the rotational aspect of "weight savings", I was simply pointing out that there more to it than just the weight. The distance between the center of rotation and the said weight also matters! So when you start increacing the diameter of rotating things, you offset some of the gains that you have from loosing rotational weight. But lost weight is lost weight, and I think that most it of comes ditching one carrier bearing.

 

[SBstar]

Sorry Leon, kind of felt like a personal attack there. The first one snapped clean at two u-joints, the second was builder error, the third seems to have vibrational issues which are causing my t-case to leak. I was going to replace it with a fourth stock one but the wifey heard everyone telling me to go aluminum and decided it would be a better investment then going through another stock one.

Also you and Phil have bad blood from way back when, chill out both of ya! Records were made to be broken and everyone is entitled to their own opinions, right or wrong.

 

[Phil1320]

Phil are you really bragging about beating my 6 year old record? I never set my car up for chacing a record, it was break-in turbo! I just noticed that it was a good turbo and took it to the track!

And YOU brought up the rotational aspect of "weight savings", I was simply pointing out that there more to it than just the weight. The distance between the center of rotation and the said weight also matters! So when you start increacing the diameter of rotating things, you offset some of the gains that you have from loosing rotational weight. But lost weight is lost weight, and I think that most it of comes ditching one carrier bearing.

That fact that I keep replying to you is a joke in itself, but, here I am.

I didn't bring anything up for you to come in here in give your piddly .02 about it.

And, yes, Leon, we've been over this: You woke up one morning and said, "Jeez, such a nice day, what shall I do?" So, you walked out to the garage and looked at your NEON green talon and then glanced aside and there was a beat up old turbo on the floor. You walked over, picked it up and in faster than any other DSMr ever time...you had it on the car. Then you decided to take the car out for your usual stroll. You accidentally ended up in the staging lanes in Epping due to a detour on your normal route. So, you decided, what the heck, I'll race. So you went out and ran 11.64 while granny shifting and not even launching hard and not having the proper set up.



If you could have gone quicker, you would have. END OF FN STORY

 

[Nate Crisman]

I have to agree with Leon (at least temporarily until doing the moment of inertia calculation), but the rotational weight is "possible" to be worse on a DSS shaft than a OEM shaft even through the DSS shaft is lighter because the diameter of the shaft has significantly changed. You need to know weight per length of the shaft material, wall thickness, outer diameter to rough calculate it.

Rotational inertia is a factor of both mass and diameter.

Lets just say that the aluminum shaft weights 1lb per foot, is a diameter of 4"... It has a moment of .040 (extremely basic/simple online calculator #)

Lets say the OEM steel shaft weights 2lb per foot and is 2" diameter....Moment of inertia is .020

The steel driveshaft takes less engine power to accelerate than than the lighter aluminum shaft in that case, as the diameter factor is worth more than the material weight. If this is the case with a DSS vs OEM shaft, one needs to judge the 10lb of static weight loss vs the increase in rotational inertial. If it saves 10lb, but wastes 4hp to turn it, it might be a new performance loss. Then factor in cost, reliability, and replacement availability. It's way more complicated to know for sure on a real driveshaft because all the joints and such are different and need to be calculated then factored in.

 

[GRNDSM]

Great recolection, Phil! You know some of this stuff better than I do... Only that last time, I went out to deliberately set the record. At that point, it was pretty clear that 14b was a very capable turbo. So I was pretty sure I was going reset the record.

Looking back, I really should have borrowed some slicks and tried it again, but I didn't, I was more inresested in breaking into the 9's.

But you take just about any light, sub-9 second DSM, slap on a 14b, RETUNE it (which could be challenging, depending on your engine management system), and you should be able to run high 10's/low 11's. Or for that matter, take of the sub-10 second "Stock Appearing Turbo" cars and see what they will do on a 14b!!!

Why aren't more people doing it? I am not sure, I found it more fun than running high 9's/low 10's!!!

I bet that is why Nate is sticking with the little turbos.

 

[Nate Crisman]

Why aren't more people doing it? I am not sure, I found it more fun than running high 9's/low 10's!!!

I bet that is why Nate is sticking with the little turbos.

Hell YEAH! This is way more fun than trying to go big power racing. I don't think even with all my blow up's this year, I still haven't done half the repair work that I did in 2005 when I was trying to go 9.9@150. That was spectacular failure on parade! I really have no interest in anything bigger than a E3 16g anymore, especially once I get my damn nitrous setup functional.

 

[SBstar]

Since we've started down this road might as well state what I think. I think there is literally zero performance gain by the aluminum driveshaft save the 10lbs saved on the weight of the car. I don't think it's going to make a lick of difference in ET or mph. I'm not going to bust out a fancy calculator and figure out exactly how much it gains or loses horsepower wise. I'd bet it's short of 1-2 hp either direction. What I do know is that it's proven to reduce vibrations, and most importantly in my mind due to aluminum being more torsional it can help save the rest of the drivetrain. I don't expect to be snapping this driveshaft anytime soon with my mad 14b powers.

 

[GRNDSM]

I am not sure how I missed this (notifications of new posts are not very consistent).

At track now:
No nitrous 14b awd auto:
1/4. 11.377 @ 116.63
1/8. 7.165 @ 94.79
60'. 1.473

Turning on 100 shot next run!!! Wish me luck.

Awesome job, Nate! 100 shot should put you deep into 10's!!!

 

[Nate Crisman]

I am not sure how I missed this (notifications of new posts are not very consistent).



Awesome job, Nate! 100 shot should put you deep into 10's!!!

Woulda-shoulda-coulda. Unfortunately it put me back on the trailer in a hurry with a torched through cyl head. I had debris in my fuel system that plugged a nitrous jet and caused catastrophic failure in cyl #3 at about 1/8mile. It still went 11.3 on the brakes at 87mph.

Next time out I'm crossing my fingers with a goal of 10.5's @ 128mph. 100hp of nitrous "should" pick up nearly 9-10mph and .90 of ET if I spray it start to finish with the same 60' and overall tuneup on the motor. Iv also go jets from 120hp up to 200hp if need be.

Oct 15th is my next day available.

 

[e85_4g63]

Where are you trying out this Oct 15th run? (what track, I'm close{ish} to you).

 

[Nate Crisman]

Where are you trying out this Oct 15th run? (what track, I'm close{ish} to you).

Englishtown, NJ Raceway Park. It's a Mitsubishi vs Subaru event. Will be about 75 million Evo, 2 million WRX, and 12 DSMs. I guess Im going to enter quick 16 just to get 3 Test & Tune qualifying passes and see what happens. By my luck thus far this year I'll be blown up by then anyway and which class I run with is moot. hahahaha.

 

[pneumo]

Good luck on the next outing!
BTW how are your coolant temps? I remember a post from last year when your ECT's were over 230. Are they still high or are they down at the start of each run?

 

[Nate Crisman]

Good luck on the next outing!
BTW how are your coolant temps? I remember a post from last year when your ECT's were over 230. Are they still high or are they down at the start of each run?

Coolant temps are good, it sits at 180* in the pits/lanes and runs 190*-193* during the run then goes back down to 180* before I hit the timeslip booth. The ECT issues from last year were due to a blown HG seal and my lack of remebering to check the water level each run. This year, topping off the radiator has been on the EVERY RUN CHECKLIST.

Between every run we do this:

• Save datalog & adjust tune
• Add fuel to 1gal cell
• Check vacuum lines for rips and connections
• Check fuel lines for leaks, check nitrous kit for leaks.
• Drain water & add ice to intercooler tank
• Check/Add radiator water
• Pull plugs & Inspect...we check compression every few runs too.
• Tire air pressure check & adjust

Sometimes it feels like we are running a damn top fuel team or something with all the between run stuff to do.

 

[Phil1320]

Oh, ok, I get it. The DSS shaft is purely aesthetic. Everyone here knows more than DSS and has their own company that's making money. At least it's nice to look at.

"My point is, it is not a very smart mod"

I guess you don't have to be smart to be fast

 

[Nate Crisman]

We've had that happen with a stock driveshaft, so I wouldn't blame it on the DSS yoke necessarily.

Yeah, I have had the yoke twist on stock driveshafts fairly often. The good thing is the stock yoke is like $23 and nearly every mitsubishi dealership parts department still has one on the shelf due to the xcase recall fiasco of the 90's. It only seems to be a problem when you break an Xcase and then can't get the busted xcase off the driveshaft in the pits. I'v never actually had a stock yoke BREAK. It just seems to twist 5* and stay there. That's when having a second complete driveshaft on hand in the trailer is quite handy.

Having two DSS shafts kicking around = $$$ x2. What's the cost of a yoke kit from DSS since that's the most common breakage? $150 or so?



On a side note: Im working on a few minor upgrades to my setup that hopefully will go on before Oct 15th @ Englishtown:

Getting an electronic box setup that will allow me to use the DSMlink EGR output to shift the trans at XXXX adjustable rpm.

swapping tires with my buddy nelson, who has 23.5" x 8 x15" M&H slicks. I feel my car can use more gear ratio. I need more applied power off the line to 60' much faster, and Im coming through the traps at like 5300rpm in overdrive to see 116mph. Can likely make use of a lighter - smaller tire & shorter final drive gearing.

hopefully going to have a conversation with some nitrous gurus and try to nail down the jetting more accurately so Im able to get right into solid runs on the spray. Really want to nail it with 150hp shot and set a good ET incase this is my last time out for 2011.

 

[hubz91talontsi]

swapping tires with my buddy nelson, who has 23.5" x 8 x15" M&H slicks. I feel my car can use more gear ratio. I need more applied power off the line to 60' much faster, and Im coming through the traps at like 5300rpm in overdrive to see 116mph. Can likely make use of a lighter - smaller tire & shorter final drive gearing.

I was going to ask about this, but forgot. Car just doesnt have the power to lower that 60'? What kind of 60' times were you hitting with the 16g?

 

[AQuinonez90]

Man I read some of the post on this thread and people say 12s on a 14b aint attainable. WTF? I have a t3t4 but since I have the 14b on my car id like to hit high 12's with that thing.