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Old 02-04-2004, 06:00 AM   #91
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hey motorman ,what head clearance and plug would you rec. for
hot weather over 80 degrees and thin air say in vegas running
nova motors at 30 or 40 %.
currently at 0.21 and very cold nova plug in la. weather.
thks 4 your support
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Old 02-04-2004, 07:39 PM   #92
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Motorman,
Thanks for the fast Reply,
I also Believe ALOT in squish. Deck Hight & Compression Ration With related Exguast Hight.
I live in Fl. So I might be on the Ragged edge For my Initial Setup.
Thanks Again.
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Old 02-05-2004, 01:35 PM   #93
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Mugen
hope it was usefull to you.

Isuzuguy
well actually vegas can be decieving. The last time I was there for the speedline race last year the air density was really high. It was detonation central for us. If your going there I would actually plan to take a two piece pipe setup and step down a plug range or maybe 2 colder if detonation becomes a problem. I would strech the pipe a quarter inch longer than your one piece setup first. The other option is to use an RD one piece pipe and take both length headers we have. start with the short one and go to the long one if detonation rears its ugly head. I pushed three engines to the limit and killed 2 of them and that has not happend to me in a long long time, Broken pistons. Gearing the car to tall can cause detonation too, as can to lean a top end adjustment. I think I would stay at 21 especially on 40 running at sea level or close to, above 80.

How to identify detonation: the plug will be burnt in a way that the plug looks gray and bristly where the wire is left. If this happens take the head off and look for the piston and or head to have a Matte sand blasted look if so the engine is detonation and it will kill itself unless steps to correct the condition are taken immediatly.


Ziggy
I'll make it easy for you
3 choices for your engine
RD one piece 615L version
Nova 625 version
Novamega TPO6

then gear the car to get the torque where you want it. A torque pipe for the sake of torque which can be compensated for with gearing will hurt you. Once you have achieved max torque by gearing the car if you still feel you could give up top end then look for a torquier pipe.
That is the way I would go about it.
RD will be releasing a new pipe I designed very soon (next month) that should jack up torque and horspower beyond the 615 RD pipe. However I still like the 615 alot and consider it one of the best value/performance pipes for the money. Theres a pipe that starts with an O that makes a good paperweight.
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Last edited by Motorman; 02-05-2004 at 01:56 PM.
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Old 02-06-2004, 05:36 PM   #94
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Motorman,

I also race at high altitude (approx 6400 ft above sea level) using 30% nitro on a RB X-12. May have experienced some detonation, at least by your description of the way the plug looks. What do I need to do to make sure this doesn't happen again? I still have stock head clearance as I have not opened the engine up for myself.
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Old 02-06-2004, 08:01 PM   #95
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Your probably not actually having detonation but I would pull the head and look if I were you. Your probably having lean plug burnout. It would appear my friend that you are at the other extreme. at that altitude the air is so thin that you could be suffering from to low compression. whats happening is you are having to overlean the engine because of the thin air to make power, because the Dynamic compression is way down. In your case I would go down to .014 head clearence and go to a hot plug and see if that does not help. I would use 40% fuel if I was in that condition.

There is a track in Mexico that when people go there you typically need a completly different head button to correct this condition. I cant remember if thats pegaso or not. I personally have not been there but I remember Ron Paris talking about it.
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Old 02-07-2004, 12:27 PM   #96
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Motorman what do you think an RD NTC3 turbo pipe would be like on an STS D5 turbo engine ? The track I'll be racing on is fairly short (100' straight) with a tight infield....

RD Logics turbo NTC3 pipe...




AE dual chamber NTC3 pipe...was considering one of these too ?? I'm soo confused

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Old 02-07-2004, 04:06 PM   #97
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on a track that short run an associated pipe. it will make more torque.(it has more flatband length in front of the weld, about 3/4 of an inch) your not going to get into the revs much. The Rd pipe is more suited for tracks between 160 and 250 ft
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Old 02-07-2004, 04:42 PM   #98
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Hey Dennis,

i just arrived in Ft Myers today and saw the track in real live.

Now I know why everybody calls it a beatch

Man that's tight, it looks soo much bigger on the pics.

I wouldn't wanna drive an 8th scale there.

Whish me luck...
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Old 02-07-2004, 06:41 PM   #99
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yea brother
and they've toned it down I hear from when I was there in 2002. That S in the front was a really bad scene. you have to be in against the wall and full throttle through there to be fast just kicking the tail out as you pass the S into the sweeper. If you hit the S your an airplane, your car will be broken guranteed. My friend Brent Gottfried used to say if you wanna be fast you gotta drop your sack and pull the hammer back.

Them Iron boards win every time! Have a good race wish you the best.
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Old 02-08-2004, 09:05 PM   #100
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Quote:
Originally posted by Boomer
Motorman - all respect to your knowledge. I missed it when you took your sabbatical from this forum.

Can you give a General principle for shimming and a starting point for, say, an MT12.

What I mean to say is - at a given % Nitro- increasing the gap generally does X (and you need to do Y to your plug). . .

Also - I've heard that you can use a piece of Solder to measure the gap. . .is that an okay method?
Motorman,

I know you probably hate questions like this (or maybe Boomer was messing with ya), but can you give us a answer?
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Old 02-08-2004, 09:13 PM   #101
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I sent him a PM. I'll see if I can dig up the text from it.
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Old 02-08-2004, 09:23 PM   #102
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Motorman wrote on 11-22-2003 06:51 PM:
Ah here it is.

General novarossi numbers, values are in thousanths not MM
.008 head clearance is built in with no shims. added recommendations include this value. Take them as they are posted

20% you can get away with .014 with a 77 plug

MT/12 30% fuel use .018 shim which is stock with an odonnel 77 plug this will yeild good results.

Changes from baseline
add.004 will add top end and lower bottom end
subtract .004 will add low end and detract top end

Plug change from 77
Hotter will advance timing and add top end
Colder will retard timing and add torque

40% use .018 +.003/4 with an odonnel 99 plug which is colder

the later will produce the most power
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Old 02-09-2004, 12:07 AM   #103
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Thanks Motorman.

All this talk about shims got me thinking about mine. I bought a used NS12 S3 off Ebay. It runs and sounds great but I haven't had it on the track. Anyhow, it has two .012" shims under the head (for a total of .024"). I very carefully used the solder trick to fine my piston/head clearance. I came up with .035"

This sounds like alot more clearance than what people here are saying they have

But my engine sounds good, it idles good, and it looked wickedly fast on a empty parking. I used 20% nitro and what looks like a NovaRossi 6 glow plow (engine came with it).
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Old 02-09-2004, 07:45 PM   #104
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I would reshim it back down to what has been recommended, you will see a power gain. It didn't come from the factory with both shims. The is .008 built in with no shims.
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Old 02-09-2004, 09:15 PM   #105
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This is a great thread...great info from everyone. After reading through I realized that I need digital calipers badly. In the meantime...Motorman, you say stock is .18. That's the button with just the silver (.3mm shim) right?
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