Rearend opinions for a crate

[FF21]

Looking for opinions about which place makes the best low drag rearend for a crate car Winters,Franklin or the DMI Bulldog?Thanks Rick

[dirty white boy]

tiger makes a good low drag....

[dynoman14]

What does low drag mean ?
And how is this drag being measured ???
How much HP is it better than the old stock heavy $1000 Winters Unit?

[rubbinsracin]

I have heard that the bulldogs are good for low drag right out of the box. I also was taking with some of the leaders at our local track and several of them indipendently said a ratcheting rear end is a big big help in any limited HP class. Something like a truetrac I guess. Anyone else know much about it?

[Casper60]

DMI is the best, hands down. Lighter and stronger than winters or tiger. While they won't make one with an 8 inch ring gear option, they do offer a lightweight option that brings a 10 inch to within ounces of an 8 inch.

[dynoman14]

C60,
Now there's a guy that is thinking...

I have tested 100's of rear end combinations for racers, vendors and manufacturers. The biggest HP gain you can make is in the lube, and how the lube is delivered to the gear and bearings.

Bearings are in the .5-1% range on power gains.
Oils are in the 2-5% range.
Oil levels 5-10%

[RW57]

Is their anything that Dyno has not done extensive testing on. 100's of rearends come on gimme a break !!!!

[Egoracing]

Is their anything that Dyno has not done extensive testing on. 100's of rearends come on gimme a break !!!!

I like in the other post where he has sold 5 pallets of valves without a single problem. I that would be a failure rate that every mfg in the world would be proud of.

[RW57]

I have never commented on any of Dyno"s post just read them for a good laugh but this one was just too much and I could not help myself .

[Egoracing]

I have never commented on any of Dyno"s post just read them for a good laugh but this one was just too much and I could not help myself .

All out of a small one man operation that does not activley seek customers, Must have been in his free time between rebuilding Serde machines, consulting cup teams, building crate engines (even though he has said that he does not build them, then he says he does), treating crate valve springs, making oil, building oil filters, chassis dyno testing cars, flow testing heads, cutting Ti valves, and testing carbs. And I know I have missed a few things that he has claimed to have tested, rebuilt, improved, or designed.

I also like that his original posts were 7500 RPM and 500+hp out of a legal crate motor and NOW he posted that those numbers are for an "Outlaw" engine that is for places that do not require the crate engines to be legal because it is different cam, lifters and pistons? I have not seen a track/series that requires crate engines that will allow you to do anything to them to modify/improve the original engine.

[Casper60]

I see dyno get bashed quite a bit on this forum, and even if he were standing in front of me, I'd have no clue who he is. I will say this much, I find alot of te tips and tricks he shares to be useful on the race car whether you believe him or not.

As for the rear end stuff, Bearings are a huge issue when it comes to power loss. Not to mention oil viscosity, amount, and even the grease you use (or don't use) on the bearings all make a difference.

Here is a little trick I learned when I raced RC cars back in the day. Put all the hub assemblies together and install them on the car as you would if you were doing final assemblies. With the rear, don't put the axles in. Now go to each corner and spin the wheels. When they finally stop, do they stop or do they rock back and forth until they settle and finally come to a stop? If they just come to a stop, you have problems. Same thing applies to the big cars.

[Egoracing]

When they finally stop, do they stop or do they rock back and forth until they settle and finally come to a stop? If they just come to a stop, you have problems. Same thing applies to the big cars.

If you have ever ballanced something on a radial ballancer, it just stops. If it rocks back and forth you have an out of ballance issue and the heavy spot is stopping the rotation and reversing the direction. If it were ballanced there would be no force to cause it to rotate backwards.
Go to an airport and watch the jet engines (not a nice word)(not a nice word)(not a nice word)(not a nice word) down, they do not have brakes in them and they NEVER reverse direction when they stop and if they were not perfectly ballanced they would come apart!

[derricklong38]

So any opinions on the rear end? or are DMI and dyno bashing all we get?

[dirty white boy]

have to say both dyno's replys here are correct,..1st one poits what to be thinking when comparing rears,..an 2nd bout berring,s lube type an amount,..no big secreats here,any body reads circletrack would know this,...but theres to many threads that get ate up dyno bashing,..or stockcar bashing or egobashing,...sad cause we all here for the same reasons,..to learn an share knowledge bout these dirt cars we alll so crazy about...


tiger,winters,DMI,bulldawg,....theres a lil company down in ether nc off 220 builds some outstanding rear ends an trannys named TEX manufacturing...good luck with your choice...

[Egoracing]

So any opinions on the rear end? or are DMI and dyno bashing all we get?

I will start of by saying Sorry for the highjacking.

Most rearends when warmed up are all really close to each other on drag. Many of the numbers you see are with a cold rear unless it is stated in the information, also, knowing you some of this latest and greatest advertising works I would wonder if they were using a heavy old style lube in the other rear and lightweight synthetic in the one they are trying to sell.
If you are looking at starting in a crate and then moving up with the same car you do not want the small light weight rears as they will not last. There have been a LOT of races won with a standard QC rearends. Just make sure they are an alumimum spool and a gear set that will allow you to get the geas ratios you need. Drilled axles will reduce overall weight but will not accelerate faster as the weight is removed from the center of the unit and the moment of inertia (how fast something accelerates with a given input) if weight X diameter squared. So a axle that weighs less will not accelerate as fast as a slightly smaller diameter axle that weighs more. This also holds true for driveshafts. I would look at Tiger or Winters.

Get a good rearend with an aluminum spool, Aluminum tubes and synthetic lube, if you are not running 75-100 lap races the thermal coatings may not even be needed. Use the money saved to get a carbon fiber driveshaft for the acceleration benefit and the saftey and get a good set of shocks and learn how to adjust them and you will be money ahead and just as fast as you would be with less money in your pocket and a super duper special ultra light weight latest and greatest rearend.