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Old 05-26-2007, 11:14 PM   #1441
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Originally Posted by spenzalii
... I'm still chasing down the shifting problems, and my rear diff let go in the main. Th ecar felt very good in the infield, but since I couldn't get it to shift into 2nd,
Thinking about going up one tooth on the 1st gear spur. If I can get the car to shift early, that may do the trick and not give up too much acceleration that 19t pinion gives you (trust me, it makes a world of difference!)
Spenzalii,
I know you located a problem with the trans before, but you may want to check the clutch shoe carrier and ensure there is no play between it and the main shaft. Maybe the combination of tire size, and the low gearing (19T) is preventing the main shaft from spinning hard enough to force a shift.
The Pinion gears 19/25 and Spur 54/48 not much difference from 55/49
pinion 20/25 and Spur 55/50 top gear limited but .75 spread
pinion 20/26 and Spur 56/50 better, with a .88 spread
You may be able to gain some acceleration by adjusting the centax clutch and getting the engine into the power band.
How did your engine perform with the stock gearing 21/27 and 55/49 combo?
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Old 05-27-2007, 08:00 PM   #1442
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Might be, not sure. I know I replaced the clutch shoe carrier not so long ago since the first one was broken. I'll pull it apart to see if this one is screwy too.

As for the gearing: It very well may be set a bit too high, but not by what other cars are running at the track. Stock gearing seems positioned for top speen more than anything else. With a ratio of 6.55 1st/4.54 2nd the car has legs for days. Around the infield, however, it feels a bit slow/soft. But once it shifts, it will pull for days. On the backstraight of my track cars would get the jump on me, but once 2nd gear kicked in I could catch or pass. Unfortunately by then I'm at the end of thr straight. Now, the de facto car of the track runs 7.36 1st / 4.89 2nd with just about any motor out there. The 19/56 combo gets me there with at 7.37, which is fast out the corners and down the straight. As long as I was out far enough in front on that straight, I was able to fend off a few people in the infield.

I'll try taking the tranny apart and goint with the 55 spur (good for 7.24). If the tranny was shifting too soon before, this may help slow it down.
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Old 05-28-2007, 07:30 PM   #1443
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Let's look at another perspective. From your description the engine is spinning up but the "vehicle speed is not high enough" to take advantage of second gear. Its like shifting from first to third in a 5speed manual in a full size car. Hence the wide ratio gearing effect. Sounds like you need a closer ratio between first and second gear, and a bigger 1st gear to use the engine's low end torque. This first gear will launch you car and get it up to the correct speed for your second gear.
Just my thoughts.
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Old 05-30-2007, 07:45 AM   #1444
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Hi can anyone tell me about this picco XP-12 P933 engine, is it an old model or not?

Thanks
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Old 05-30-2007, 10:06 PM   #1445
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joe,
That XP-12 is definately a few years old. If memory serves, that was released around the same time, or maybe even slightly before, the grandaddy MT12. It will do the job, but you may not match the speed of some of the newer models that are out now, and not just the big buck models either.

CT,
Pretty good analogy with the 5 speed. However, with the stock gearing, it's like starting in 2nd, or even 3rd gear. Over the weekend I had the car back to shifting, but still a bit early. I'm replacing the springs and shoes with the Ofna parts and see what's what. Worst case scenario I can move 2nd gear up to the 5 range and just have a quick accelerating car, and see how well it handles the overrun on the backstraight.
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Old 06-07-2007, 07:45 PM   #1446
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Quote:
Originally Posted by spenzalii View Post
CT,
Pretty good analogy with the 5 speed. However, with the stock gearing, it's like starting in 2nd, or even 3rd gear. Over the weekend I had the car back to shifting, but still a bit early. I'm replacing the springs and shoes with the Ofna parts and see what's what. Worst case scenario I can move 2nd gear up to the 5 range and just have a quick accelerating car, and see how well it handles the overrun on the backstraight.
Spenzalii,
How far can you g owith mixing the gear sets that are not matched with the same gear tooth spacing. What I am asking is if you are using a 19/26 pinion , 56/50 spur and move up to a 55/50 spur, will the gears mesh properly??
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Old 06-07-2007, 08:07 PM   #1447
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Originally Posted by CurveTracer View Post
Spenzalii,
How far can you g owith mixing the gear sets that are not matched with the same gear tooth spacing. What I am asking is if you are using a 19/26 pinion , 56/50 spur and move up to a 55/50 spur, will the gears mesh properly??
With the 0.8 pitch gears (the black ones), yes. With the 1.0 pitch gears (the grey ones), no. The Pro has the smaller pitch gears that are the same diameter regardless of how many teeth they have.




The stock gears you do have to make sure the gear spread is the same, since the diameter changes with the number of teeth. It gives you a few more options on gearing, and the mesh seems a bit smoother.

In other news, the big race starts tomorrow. Unfortunately it looks like I may miss the first day of qualifiers. I still need to get a few things from the shop and my sons promotional exercise is tomorrow. I may only have time for one run. We will see
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Old 06-09-2007, 05:30 PM   #1448
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Boy oh boy. This race is absolutely nuts. Cars are flying, a slew of people are having run time issues since the track is so fast, and it's HOT. I'm almost to the point I can get my tranny issues worked out for the mains and hope to bump up. After that, I'm ordering new shoes & springs (and maybe the 2nd gear holder) for next week. I rebuilt the centax and if that Ninja didn't have snap before, it definately does now!

As for the race, it has been great. Yesterday I'm talking to Josh Cyrul and Ralph Burch about the track, racing and bowling! Bary Baker was on the other end of the table, Paul Lemeuix and Ron Atokic were in the mix, Paolo Morganti and DJ Apolero (sp) were holding it down for the Serpent faithful...and they ALL put it down. Only 1 local guy is in the top 5 in 1/10. The mains tomorrow are going to be on some Nationals level racing.
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Old 06-09-2007, 10:30 PM   #1449
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Sounds like the experts are knocking problems down, and everyone else is finding a way to keep racing. What did you change when you rebuilt the centax clutch? What parts degrade over time, chutch springs? clutch shoe?
How many racers have their own private mechanic/pitman?

What amazes me is that some of these cars fly through a chicane with the wheels turned full, then get turning grip through a short corner.

Good luck tomorrow!!
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Old 06-11-2007, 11:37 AM   #1450
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Had to replace the clutch spring. It shrunk with the heat. The new spring gave it more snap. The clutch shoe is just fine (using the yellow Mugen shoe, which seems to be the ticket these days)

Ended up 2nd (started 10th) in the G main, got my trophy plate too. If they post the pics I'll link them up. Considering these were the guys in the A main, I'm not mad:

2007 Capitol Classic

Pro 1-10th Sedan A Main Round# 7, Race# 17

________________________Driver___Car#____Laps____R aceTime____Fast Lap___Behind_
DJ Apolaro #7 126 45:13.684 20.259
Vincent Jackson #5 123 45:16.528 20.627
Ron Atomic #4 122 45:09.355 20.599
Joe Sumasky #11 121 45:14.083 20.714
Mike Dunnigan #12 120 45:09.092 21.201
Josh Cyrul #6 109 41:13.251 20.546
Uriah Murnan #9 107 45:00.762 20.744
Ralph Burch Jr #1 103 37:04.519 19.830
Bobby Flack #8 94 38:06.099 20.411
Paolo Morganti #3 87 37:41.582 20.409
Barry Baker #2 79 28:31.049 20.084
Brian Thomas #10 5 13:15.342 21.575

All I can say is if you are anywhere close to the east coast next year, you have to come out. Some of the factory guys are seriously going to push for a Nationals here, and we just may get it.

I'll get my setup out later this week. It drove well enough for me, and I could have done better if I had the tranny sorted out. Sunday it shifted into 2nd, but way too early. I figured that was better than not shifting at all, so I left it be and drove it as best I could. That meant pretty much staying on the throttle thru most turns just to keep the rpms up. Couple that with the cool weather causing all the cars to run rich and the car wasn't as fast as it could have been. But it finished the 20 minute main in one piece and brought home some hardware, so I am not mad at all. I think I will try those Mugen springs again. I may have figured out how to get them to work. If not, a new set will be on order from Nitrohouse.
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Old 06-20-2007, 09:17 PM   #1451
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Spencalli,
Congrats on a great finish!!!
That's the main idea, you cannot win unless you finish. I have been racing locally at Leisure Hours Raceway in Joliet. I have been refining my race setup, engine tune and driving. I have shaved a second an a half off my lap times in three race outings. The traction is marginal, but I am getting better.
I have migrated back to the Purple (30 lb.) springs on front and rear, with the front sway bar flat and the rear bar disconnected.
My diffs are now 6-gear 50k front and 20k rear. It took a while but I was able to compare different diff combos and feel the driving difference.
What do you think a CD3 would handle like with sligntly heavier springs in the rear than the front, remember the weght bias is toward the rear.
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Old 06-21-2007, 01:02 AM   #1452
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Curvetracer, harder spring in the rear will give you less rear traction and could make your tail end loose. Generally the rule of thumb is to have softer springs in the rear. but its a quick and easy change so you can experiment.

My MTX4R is doing very nicely, still need to get a good setup on it tho, but my lap times have dropped about 2s and i am way more consistent with the mugen, still trying to get used to the front spool tho, i have only done 2 race days with it so far, havent even had a chance to go and practice, the only time i have driven it so far is under race conditions. will let you know a direct comparison between the 2 as soon as i get the CD3 parts i am waiting for so i can drive both on the same day.
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Old 06-21-2007, 03:08 PM   #1453
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Curvetracer, harder spring in the rear will give you less rear traction and could make your tail end loose. Generally the rule of thumb is to have softer springs in the rear. ...
1. Yea, I know but the reason I am posting the question for comment is that the F/R spring config I have been using was Yellow(35 lb)/Red (20 lb.). The red springs made the rear end too soft for chicanes and quick direction changes. I evolved back to the F/R purple (30 lb)/purple (30 lb) configuration that I used last season for medium low to low traction tracks. I am looking at longitudinal and lateral traction. I'll post results when I get them.

2. Wow 2 seconds is a lot of time saved, which implies that the Mugen design yields a broader range for the optimal chassis setup. Which portion of your track are you faster on with the MTX4? Are you able to throw the car into corners faster and hold higher mid corner speed??
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Old 06-22-2007, 12:51 AM   #1454
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Curvetracer, i think its a combination of the new nova plus 12 and the mtx4 thats helping drop the times, im definately much faster around the sweeper and back straight and the infield is also better, but it doesn't have as much initial turn in comapred to the cd3 but thats probably because of the front spool, but there is plenty on power steering. But like i said i still need to play with set up first, going to try sneak off to the track today if i can (charging batts now just incase)
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Old 06-22-2007, 12:27 PM   #1455
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Well guys, it looks like I'm finally getting my G4s this weekend. I'm really looking forward to working with a different car. I'm going to keep my CD3 as a back up for now, but may look into selling it again. We'll just wait and see.

Good Luck Guys!
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