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Old 05-10-2009, 07:31 PM   #841
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NDZ,

Although I understand that Irrgang Racing Services (IRS) makes the rear axle for the CRC Gen-X10, I have switched my CRC supplied axle out for an actual IRS unit. And have had no trouble since. Only comes in silver when I ordered the axle assembly from IRS. That was probably 6 months ago with no reoccurances after switching.

I love the Slapmaster Tools Thrust Bearing Kits for pan cars; but, the first production one I received for my Gen-X 10 from SMT wasn't machined quite right. Brian at Slapmaster figured out my issue and corrected that for me pronto. If you have any issues with the one you have, contact Brian for the #120 Thrust Bearing Kit.

I am also a big fan of "John's thread". One of my favs on RCTech.net.

Hopefully, we will have a lot to talk about after seeing the new ROAR announcement about going to single cell for pan cars.

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Old 05-10-2009, 07:35 PM   #842
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Comparison of Four 3.5's

Here are the results of the dyno runs on four 3.5 motors that are popular. From a user standpoint what I want to know is what car are they going to work best in, 4 wheel drive touring car, or wide pan car. What is the relative gearing between the motors. How much heat is going to be evolved.

I have run three of these motors so I think I can predict with confidence what the Novak Ballistic motor, which I have not run, will perform like based on the dyno runs. Here is some track data followed by examination of some of the dyno data. Yes that is a complicated graph. But this is the only way to see the trends between the motors based on dyno output.

Novak Velocity 3.5 -I have run this in the wide pan and the touring car. Gearing is very low. Power is great. Punch at low RPM is mild. This suits this motor to the wide pan which has low forward traction to start with and then as that wing adds on rear downforce you can use huge power to accelerate. In the touring car you will find it is a little soft out of the corners. Slower parts of the track are more important to laptimes in most racing. You spend more time there.

LRP X11 3.5 - This motor has monstrous corner exit punch. It is a little lower in RPM and power. You gear it a little taller, as much as 4, 48 pitch teeth higher than a Novak velocity 3.5. It is great in a
4 wheel drive touring car, but tends to break the tires loose on the wide pan car.

LRP X 12 3.5 - This motor is almost a duplicate of the early Novak 3.5. Power is huge. RPM's are high requiring low gearing. In spite of venting it runs hot and needs even lower gearing. 9.0 in the TC on a big track. Corner exit punch is less than the previous X11 3.5. It is wickedly fast middle of every short straight but does not wickedly jump to speed right out of the corner. This would be a great motor in the Wide pan.

Novak Ballistic 3.5 - I have not run this motor but you can compare the four power curves and predict its abilities. Notice the Green Power curve is the highest at lower RPM, the left side of the graph. This indicates that the motor is going to be the punch king if it can be geared appropriately. Heat generated will be less than the previous 3.5 due to a little detuning up high (the green line is a little lower than the others at high RPM) and more efficiency down low the light green line is high on the left side.

Note that what leads me to this conclusion are the purple lines describing the LRP X 11 3.5. The higher purple line shows power and shows somewhat of a bulge above the others at lower RPM toward the left of center. This is giving the TC max punch out of slow corners. The best I have ever seen.

Well the numbers are in. I suggest the Novak Ballistic in the TC, LRP X12 in the wide pan.
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-lrp-x12.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-novak-ballistic-3.5-motor-003.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-lrp-pro-comp-x11-3.5-reflection-resized-tight.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-novak-gtb-3.5r.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-all-four-3-5s5-10-2009002.jpg  

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Last edited by John Stranahan; 05-12-2009 at 09:37 AM. Reason: corrected gear ratio
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Old 05-11-2009, 12:18 AM   #843
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Originally Posted by NDZ View Post
Hi there John,

I'm a big fan of your toppics en read them with great interest. I have 1 question though on wich I couldn't find the answer to.
I run a 10x on a big track in Holland (MACH Heemstede) with a X12 4.5 and I can't get the diff to work properly. I use a slapmaster thrust but the diff keeps slipping. When I tighten it, it looses proper diff-action.
I hope you can give me some tips to straighten this out.

Thanx in advance.

Niels
Put two or three belleville washers between the diff nut and the rest of the diff. This gives the diff some additional spring and also prevents you from overtightening the thrust bearing.
This same system was used on some older pancars and is still used on Tamiya's F103.
Also be sure the use the aluminium lock nut included with the thrust bearing kit. The nylon nuts (even ones that are not pre-threaded) loosen over time - where 'time' can be as quick as one 5-minute run...

Personally I think that the Slapmaster thrust bearing is a bit small and could have a larger diameter.
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Old 05-11-2009, 02:13 AM   #844
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John,

Have you ever had a thermal shutdown with your Novak Velocity 3.5?

We have found that if you start getting into the really fast zone, the zone where the track has reasonable traction and you can dump a 5000 mAH Lipo in 5 minutes, the Novak will overheat and shut down before the end of your heat.

This seems to be due to the fact that we can't really gear a pancar correctly for it. Rollout should around 24mm, which you can only achieve with really small tires.
All 4 of us running the 3.5 were confronted with this at one point, so we swapped to other brands.

We have been very happy with Mamba max 7700s and Corally's XBP 4.5 and 4.0 motors.

Especially the Corally 4.0 is wicked fast, yet very controllable.
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Last edited by Pro ten Holland; 05-11-2009 at 02:01 PM.
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Old 05-11-2009, 09:27 AM   #845
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Mathijs-Thanks for the additional motor info.

I use an LRP TC edition speed control now. It does not have motor thermal shutdown capability as far as I know. So no, I don't get thermal shutdowns any more. I do occasinally get the motor too hot, but the speed control stays cool.

I found out recently that the LRP speed controls use active timing. This means at low RPM timing is retarded. This give more bottom end punch but at reduced amp draw compared to a speed control without this feature; this shows up on the amp curve on dyno runs. I think this feature is partially responsible for the cool running of the speed control.

The new Novak ballistic series motor is quite different than the old velocity series. I'll report more on it when I get some track time. It is in the 4 wheel drive touring car right now. You should be able to use a bigger gear with it in a Wide pan. It has more efficiency and power at lower RPM's than the other motors I tested.

Note that a front diffuser knocks about 20 degrees off the temperature of the motor up high. There is a draft of air above the chassis now.
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Last edited by John Stranahan; 05-12-2009 at 09:38 AM.
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Old 05-13-2009, 01:08 PM   #846
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Dual A-arm Front Suspension

I thought I would give a progress report on this suspension. I have road tested it now and found it as good as previous models I have made. It has superior ruggedness to previous models due to an ultra stout lower arm fashioned out of CRC's very good Pro Strut lower Arm. Quante has helped me get a head start on CAD work. I thought I would show this conceptualized CRC pro Strut suspension that I received as it looks so cool. Many thanks.

Here are the main advantages of the prototype.
Unequal length A-arms for the lowest possible tire scrub as the suspension goes up into bump. This means that cornering power is not sapped by dragging the tire sideways accross the asphalt.

Very Direct Damping. The position of the shock is ideal. As close to the wheel as possible. No suspension arm torque and twist are caused by bumps and the wheels return to ground; this twisting creates extra friction in the joints which saps cornering power.

The suspension will require only three custom cut graphite pieces so it should be a simple task to retrofit to a CRC or Associated style narrow car to make it wide.

I'll make another report as I get it tuned up for the track. New asphalt is being layed down this week. It should be high bite.
Attached Thumbnails
CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-pro-strut-front-suspension001.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-dual-arm-front-end-001.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-dual-arm-front-end-002.jpg   CRC Battle Axe, GenXPro 10, 1/10th pan, Brushless, Lipo,4c, Road, Oval,TipsandTricks-dual-arm-front-end-005.jpg  
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Last edited by John Stranahan; 05-13-2009 at 05:48 PM.
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Old 05-13-2009, 02:25 PM   #847
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Dual A-arm Front Suspension

I thought I would give a progress report on this suspension. I have road tested it now and found it as good as previous models I have made. I has superior ruggedness to previous models due to an ultra stout lower arm fashioned out of CRC's very good Pro Strut lower Arm. Quante has helped me get a head start on CAD work. I thought I would show this conceptualized CRC pro Strut suspension that I received as it looks so cool. Many thanks.

Here are the main advantages of the prototype.
Unequal length A-arms for the lowest possible tire scrub as the suspension goes up into bump. This means that cornering power is not sapped by dragging the tire sideways accross the asphalt.

Very Direct Damping. The position of the shock is ideal. As close to the wheel as possible. No suspension arm torque and twist are caused by bumps and the wheels return to ground; this twisting creates extra friction in the joints which saps cornering power.

The suspension will require only three custom cut graphite pieces so it should be a simple task to retrofit to a CRC or Associated style narrow car to make it wide.

I'll make another report as I get it tuned up for the track. New asphalt is being layed down this week. It should be high bite.
Good to see the files loaded properly!! Only the steering blocks, I added 2 reference sets in my CAD file of the steering blocks, one for left, one for right so they're both available in the same file but you can choose which representation you want.
I have no idea if autocad has the option, but it'll prolly have it.
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Old 05-15-2009, 01:57 PM   #848
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Hi Guys,

Thanks for the tips on the diff. Thomas, the belleville washers work like a charm. Diff is smooth en doesn't slip anymore.

Niels
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Old 05-16-2009, 11:26 PM   #849
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does the "1287 - Metal Spring Holders" contain the set screws as well? It is on the picture together with the spring holders but it doesn't specificly say it comes with the set screws? Or does it only contain the 2 metal holders?
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Old 05-16-2009, 11:32 PM   #850
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I have ordered that part. It came with the long set screws.
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Old 05-16-2009, 11:56 PM   #851
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Per the CRC website...

The replacement for the metal spring retainers is:

"P/N: #3387 CRC Molded Spring Retainers

These molded side spring retainers are awesome, far superior to the old metal spring holders. Lightweight, easy to pop the spring on, and there is a groove molded into them for the coil of the spring to set into so the spring is not tweaked to the side. Retail $2.99 / pair"

I do not have a set of these yet; so, I don't know if they come with the allen set screws.
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Old 05-17-2009, 12:15 AM   #852
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Any ony one tried the molded version? I am not sure if they are better then the metal ones. It seems to me the metal ones could be more durable?
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Old 05-17-2009, 12:23 AM   #853
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Any ony one tried the molded version? I am not sure if they are better then the metal ones. It seems to me the metal ones could be more durable?
I have had issues with cocked springs on the metal retainer units; so, I would be inclined to believe CRC's description within my post. Deem CRC boys know this stuff!

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Old 05-17-2009, 12:51 AM   #854
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what do you mean by cocked springs? how does a cocked spring look like?
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Old 05-17-2009, 06:24 PM   #855
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what do you mean by cocked springs? how does a cocked spring look like?
It doesn't sit quite straight when coupled to the retainer unit...causing it to not evenly contact the chassis plate below...making it "cocked".
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