Dynamite .21 sport (DYN0807B) any good?
10-06-2015, 10:17 AM
#1
Member
Thread Starter
Join Date: Aug 2014
Location: Western Chicagoland
Posts: 84
Likes: 0
Received 0 Likes
on
0 Posts
Dynamite .21 sport (DYN0807B) any good?
So I blew up an SH28 and am doing a little skimming of the online retail sites for a replacement for the off-road buggy it came from. Although the SH may be restored ..... I'm a realist, and know that I just might be better off with an all new unit.
Here are the options I found that I think will work without mods, be able to use roto start I have from the old SH, and be good value:
http://www.ebay.com/itm/Dynamite-21-...-/131387631780
Listed at $65 when I looked. Cheap. Can't find a spec, but assume it's the equal of the base 3 port SH (SH M21-p3).
Here is the only review I found:
http://www.rctech.net/forum/offroad-...port-21-a.html
Or I could get another EX 28, which I have about 1/2 gallon through, and seems ok (but what do I know, I just blew a engine with 5 quarts through it!)
http://www.nitrorcx.com/mad-ed100110.html
Always listed at $90. Also cheap for the equivalent of an SH M28-P3
Experience, specification, comments? Even better yet, other alternatives.
Here are the options I found that I think will work without mods, be able to use roto start I have from the old SH, and be good value:
http://www.ebay.com/itm/Dynamite-21-...-/131387631780
Listed at $65 when I looked. Cheap. Can't find a spec, but assume it's the equal of the base 3 port SH (SH M21-p3).
Here is the only review I found:
http://www.rctech.net/forum/offroad-...port-21-a.html
Or I could get another EX 28, which I have about 1/2 gallon through, and seems ok (but what do I know, I just blew a engine with 5 quarts through it!)
http://www.nitrorcx.com/mad-ed100110.html
Always listed at $90. Also cheap for the equivalent of an SH M28-P3
Experience, specification, comments? Even better yet, other alternatives.
Last edited by ijpom; 10-07-2015 at 07:42 AM. Reason: engine desinations corrected
10-12-2015, 05:58 AM
#2
Senior Member
You can buy brand new Novarossi 28-8 ports for $160.00 these days...$90.00 for a used RTR 28 is grossly over priced.............
If your open to using a starter box there are some killer values with Novarossi right now, can buy a Novarossi Top Elite 5 for $139.00..which is a killer engine based off a P5 XLT...........
The $65.00 Dynmaie Sport is a reasonable replacement, its price is about right for what it is.....
If your open to using a starter box there are some killer values with Novarossi right now, can buy a Novarossi Top Elite 5 for $139.00..which is a killer engine based off a P5 XLT...........
The $65.00 Dynmaie Sport is a reasonable replacement, its price is about right for what it is.....
10-12-2015, 07:03 AM
#3
Member
Thread Starter
Join Date: Aug 2014
Location: Western Chicagoland
Posts: 84
Likes: 0
Received 0 Likes
on
0 Posts
Hi Super, thanks for the input.
The EX28 is new at retailer for $90. It is identical to my truggy engine that has the 1/2 gallon though it.
I haven't looked at anything exotic like a Novarossi. If they could be described as easy to tune and robust for non-professionals to use, then I could be interested. I presently don't have a starter box, so that would end up being another $60 - $100 of equipment added to the price. Takes some interest away.
The other vehicle I have still has the EX28 with roto start, and consequently a large back plate, and is mounted too high to use a bump box and a roto start.
Really my biggest issue is that I can't determine what happened to the blown SH28 engine. Couple of options come to mind:
a) User error. My break in was cautious, and was too rich and too cold for too long. Or, my end tune was a contributor to the failure.
b) The engine was flawed, and was going to pop anyway. I never got the best tune on that SH28 and perhaps that was a sign all along?
It would be an easy choice to opt away from the SH manufactured engines if it was b).
It would be difficult to spend hundreds on an awesome engine and starting equipment, if I was going to blow another with just over a gallon on it.
The capacity change from SH28 to Dynamite Sport 21 (or other 21), would be no concern in a buggy application?
The EX28 is new at retailer for $90. It is identical to my truggy engine that has the 1/2 gallon though it.
I haven't looked at anything exotic like a Novarossi. If they could be described as easy to tune and robust for non-professionals to use, then I could be interested. I presently don't have a starter box, so that would end up being another $60 - $100 of equipment added to the price. Takes some interest away.
The other vehicle I have still has the EX28 with roto start, and consequently a large back plate, and is mounted too high to use a bump box and a roto start.
Really my biggest issue is that I can't determine what happened to the blown SH28 engine. Couple of options come to mind:
a) User error. My break in was cautious, and was too rich and too cold for too long. Or, my end tune was a contributor to the failure.
b) The engine was flawed, and was going to pop anyway. I never got the best tune on that SH28 and perhaps that was a sign all along?
It would be an easy choice to opt away from the SH manufactured engines if it was b).
It would be difficult to spend hundreds on an awesome engine and starting equipment, if I was going to blow another with just over a gallon on it.
The capacity change from SH28 to Dynamite Sport 21 (or other 21), would be no concern in a buggy application?
10-12-2015, 07:14 AM
#4
There are literally thousands and thousands of SH based engines out there under at least a half dozen brand names (LRP, Losi/Dynamite/Mach, XTM, etc.) that run fine. Any manufacturer can have a dud here and there, but for the most part they are made well and run well also. Most RTR engines aren't that tightly fitted and so are easier to break in and the carbs are often copied from a known good design and as such function well also.
I have a Ron Paris Racing modified Novarossi .21 sitting in its box unrun waiting for a home, but I'm not in a hurry to find a home for it due to the cost of A) getting a buggy to put it in and B) getting a starter box. It's a well made engine no doubt, but if I were replacing an engine in a RTR basher truck, I don't know that I would step up to a top tier Novarossi or similar engine until my tuning skill set was top notch if I were pretty new to the hobby. Also, these Nova engines are usually a fair bit stronger than what I call the "cheapies" and as such can cause problems with beating up the drivetrain of the truck.
I have a Ron Paris Racing modified Novarossi .21 sitting in its box unrun waiting for a home, but I'm not in a hurry to find a home for it due to the cost of A) getting a buggy to put it in and B) getting a starter box. It's a well made engine no doubt, but if I were replacing an engine in a RTR basher truck, I don't know that I would step up to a top tier Novarossi or similar engine until my tuning skill set was top notch if I were pretty new to the hobby. Also, these Nova engines are usually a fair bit stronger than what I call the "cheapies" and as such can cause problems with beating up the drivetrain of the truck.
10-12-2015, 07:47 AM
#6
Senior Member
Hi Super, thanks for the input.
The EX28 is new at retailer for $90. It is identical to my truggy engine that has the 1/2 gallon though it.
I haven't looked at anything exotic like a Novarossi. If they could be described as easy to tune and robust for non-professionals to use, then I could be interested. I presently don't have a starter box, so that would end up being another $60 - $100 of equipment added to the price. Takes some interest away.
The other vehicle I have still has the EX28 with roto start, and consequently a large back plate, and is mounted too high to use a bump box and a roto start.
Really my biggest issue is that I can't determine what happened to the blown SH28 engine. Couple of options come to mind:
a) User error. My break in was cautious, and was too rich and too cold for too long. Or, my end tune was a contributor to the failure.
b) The engine was flawed, and was going to pop anyway. I never got the best tune on that SH28 and perhaps that was a sign all along?
It would be an easy choice to opt away from the SH manufactured engines if it was b).
It would be difficult to spend hundreds on an awesome engine and starting equipment, if I was going to blow another with just over a gallon on it.
The capacity change from SH28 to Dynamite Sport 21 (or other 21), would be no concern in a buggy application?
The EX28 is new at retailer for $90. It is identical to my truggy engine that has the 1/2 gallon though it.
I haven't looked at anything exotic like a Novarossi. If they could be described as easy to tune and robust for non-professionals to use, then I could be interested. I presently don't have a starter box, so that would end up being another $60 - $100 of equipment added to the price. Takes some interest away.
The other vehicle I have still has the EX28 with roto start, and consequently a large back plate, and is mounted too high to use a bump box and a roto start.
Really my biggest issue is that I can't determine what happened to the blown SH28 engine. Couple of options come to mind:
a) User error. My break in was cautious, and was too rich and too cold for too long. Or, my end tune was a contributor to the failure.
b) The engine was flawed, and was going to pop anyway. I never got the best tune on that SH28 and perhaps that was a sign all along?
It would be an easy choice to opt away from the SH manufactured engines if it was b).
It would be difficult to spend hundreds on an awesome engine and starting equipment, if I was going to blow another with just over a gallon on it.
The capacity change from SH28 to Dynamite Sport 21 (or other 21), would be no concern in a buggy application?
10-12-2015, 07:55 AM
#7
Senior Member
Hi Super, thanks for the input.
The EX28 is new at retailer for $90. It is identical to my truggy engine that has the 1/2 gallon though it.
I haven't looked at anything exotic like a Novarossi. If they could be described as easy to tune and robust for non-professionals to use, then I could be interested. I presently don't have a starter box, so that would end up being another $60 - $100 of equipment added to the price. Takes some interest away.
The other vehicle I have still has the EX28 with roto start, and consequently a large back plate, and is mounted too high to use a bump box and a roto start.
Really my biggest issue is that I can't determine what happened to the blown SH28 engine. Couple of options come to mind:
a) User error. My break in was cautious, and was too rich and too cold for too long. Or, my end tune was a contributor to the failure.
b) The engine was flawed, and was going to pop anyway. I never got the best tune on that SH28 and perhaps that was a sign all along?
It would be an easy choice to opt away from the SH manufactured engines if it was b).
It would be difficult to spend hundreds on an awesome engine and starting equipment, if I was going to blow another with just over a gallon on it.
The capacity change from SH28 to Dynamite Sport 21 (or other 21), would be no concern in a buggy application?
The EX28 is new at retailer for $90. It is identical to my truggy engine that has the 1/2 gallon though it.
I haven't looked at anything exotic like a Novarossi. If they could be described as easy to tune and robust for non-professionals to use, then I could be interested. I presently don't have a starter box, so that would end up being another $60 - $100 of equipment added to the price. Takes some interest away.
The other vehicle I have still has the EX28 with roto start, and consequently a large back plate, and is mounted too high to use a bump box and a roto start.
Really my biggest issue is that I can't determine what happened to the blown SH28 engine. Couple of options come to mind:
a) User error. My break in was cautious, and was too rich and too cold for too long. Or, my end tune was a contributor to the failure.
b) The engine was flawed, and was going to pop anyway. I never got the best tune on that SH28 and perhaps that was a sign all along?
It would be an easy choice to opt away from the SH manufactured engines if it was b).
It would be difficult to spend hundreds on an awesome engine and starting equipment, if I was going to blow another with just over a gallon on it.
The capacity change from SH28 to Dynamite Sport 21 (or other 21), would be no concern in a buggy application?
10-12-2015, 10:25 AM
#8
Member
Thread Starter
Join Date: Aug 2014
Location: Western Chicagoland
Posts: 84
Likes: 0
Received 0 Likes
on
0 Posts
Thanks for the greater explanation for tuning Neal. The hanging idle is something I was trying to add since I re-read the Paris Engine Bible.
Here is a quote:
A) "Set the low end or idle. After getting top end set close, bring model in, listen to the idle. If it is
idling fast then it slows down in a few seconds, it is probably too RICH on the bottom (minimum
spray bar). In that case, make it more lean (turn clockwise ¼ turn), then run another lap and
bring the car in again. Repeat this procedure until the idle stays high for at least 10 to 20
seconds; at this point readjust the aircrew so the idle is at a moderate speed. The wheels should
not turn, and the clutch should be fully engaged."
Are you saying the HSN is set too lean if there is a hanging idle after high speed run?
Paris seems to think that the LSN is too rich if there is no hanging idle for 10-20 sec.
I do like finely tuned precision equipment, but the rest of my gear says "budget racer". Lots of stock RTR redcat parts.
If I'm still doing this in a few years, I'd bet that a higher end car and engine are going to be involved.
Here is a quote:
A) "Set the low end or idle. After getting top end set close, bring model in, listen to the idle. If it is
idling fast then it slows down in a few seconds, it is probably too RICH on the bottom (minimum
spray bar). In that case, make it more lean (turn clockwise ¼ turn), then run another lap and
bring the car in again. Repeat this procedure until the idle stays high for at least 10 to 20
seconds; at this point readjust the aircrew so the idle is at a moderate speed. The wheels should
not turn, and the clutch should be fully engaged."
Are you saying the HSN is set too lean if there is a hanging idle after high speed run?
Paris seems to think that the LSN is too rich if there is no hanging idle for 10-20 sec.
I do like finely tuned precision equipment, but the rest of my gear says "budget racer". Lots of stock RTR redcat parts.
If I'm still doing this in a few years, I'd bet that a higher end car and engine are going to be involved.
10-12-2015, 10:39 AM
#9
Senior Member
Thanks for the greater explanation for tuning Neal. The hanging idle is something I was trying to add since I re-read the Paris Engine Bible.
Here is a quote:
A) "Set the low end or idle. After getting top end set close, bring model in, listen to the idle. If it is
idling fast then it slows down in a few seconds, it is probably too RICH on the bottom (minimum
spray bar). In that case, make it more lean (turn clockwise ¼ turn), then run another lap and
bring the car in again. Repeat this procedure until the idle stays high for at least 10 to 20
seconds; at this point readjust the aircrew so the idle is at a moderate speed. The wheels should
not turn, and the clutch should be fully engaged."
Are you saying the HSN is set too lean if there is a hanging idle after high speed run?
Paris seems to think that the LSN is too rich if there is no hanging idle for 10-20 sec.
I do like finely tuned precision equipment, but the rest of my gear says "budget racer". Lots of stock RTR redcat parts.
If I'm still doing this in a few years, I'd bet that a higher end car and engine are going to be involved.
Here is a quote:
A) "Set the low end or idle. After getting top end set close, bring model in, listen to the idle. If it is
idling fast then it slows down in a few seconds, it is probably too RICH on the bottom (minimum
spray bar). In that case, make it more lean (turn clockwise ¼ turn), then run another lap and
bring the car in again. Repeat this procedure until the idle stays high for at least 10 to 20
seconds; at this point readjust the aircrew so the idle is at a moderate speed. The wheels should
not turn, and the clutch should be fully engaged."
Are you saying the HSN is set too lean if there is a hanging idle after high speed run?
Paris seems to think that the LSN is too rich if there is no hanging idle for 10-20 sec.
I do like finely tuned precision equipment, but the rest of my gear says "budget racer". Lots of stock RTR redcat parts.
If I'm still doing this in a few years, I'd bet that a higher end car and engine are going to be involved.
Sadly he has it wrong........following that advice to tune will just blow your engine up as you have found.... what he is saying is 100% backwards
Hanging RPM is always lean ! if you go rich and they just stall instantly...nowhere between rich and properly tuned does the idle start to hang......
read my tuning guide...watch a couple of my videos.... then try to match the sound of my engines with yours ..listen to how my engines idle down and how they idle slow and low....
https://www.youtube.com/watch?v=7FMgvkj8c04
10-12-2015, 10:43 AM
#10
The Paris tuning bible refers to adjusting the spraybar when dealing with the hanging idle. Most engines have a 2-needle carb and not the 3-needle carb that engines like Novarossi come with. The spraybar adjustment is only there to adjust the midrange transition from idle to WOT. This is a nice feature when you're trying to tune an engine more precisely.
You can get a fine transition with a 2-needle carb. I usually set my engines so the engine drops to idle quickly after a speed pass as Neal suggests. The high end I set so it will keep revving and revving until it hits a plateau without sagging. This involves starting rich and working your way leaner noting the sound the engine makes. As Neal says, the sound of the engine will tell you how it's running and when you attain the ear for it, know what to do based on those sounds. If it revs up and then starts to slow down a little while running WOT, it's too lean. I like to have the low end set a bit richer - such that it will idle and not flame out on transition after idling for 10-15 seconds. The guys that say to set the idle mix so it will idle for 30+ seconds and give a perfect transition likely are setting the bottom pretty lean IMO. Another way to set the idle mixture is to keep leaning the idle (from a rich setting) until it cuts out when you jab the throttle and then richen it back up 1/8-1/4 turn.
When you change the idle stop to change the idle speed, the low speed mixture will be affected. Closing the slide (lower idle) leans the fuel mix and opening the slide richens the mixture, so adjust accordingly.
You can get a fine transition with a 2-needle carb. I usually set my engines so the engine drops to idle quickly after a speed pass as Neal suggests. The high end I set so it will keep revving and revving until it hits a plateau without sagging. This involves starting rich and working your way leaner noting the sound the engine makes. As Neal says, the sound of the engine will tell you how it's running and when you attain the ear for it, know what to do based on those sounds. If it revs up and then starts to slow down a little while running WOT, it's too lean. I like to have the low end set a bit richer - such that it will idle and not flame out on transition after idling for 10-15 seconds. The guys that say to set the idle mix so it will idle for 30+ seconds and give a perfect transition likely are setting the bottom pretty lean IMO. Another way to set the idle mixture is to keep leaning the idle (from a rich setting) until it cuts out when you jab the throttle and then richen it back up 1/8-1/4 turn.
When you change the idle stop to change the idle speed, the low speed mixture will be affected. Closing the slide (lower idle) leans the fuel mix and opening the slide richens the mixture, so adjust accordingly.
10-12-2015, 12:44 PM
#11
Senior Member
The Paris tuning bible refers to adjusting the spraybar when dealing with the hanging idle. Most engines have a 2-needle carb and not the 3-needle carb that engines like Novarossi come with. The spraybar adjustment is only there to adjust the midrange transition from idle to WOT. This is a nice feature when you're trying to tune an engine more precisely.
You can get a fine transition with a 2-needle carb. I usually set my engines so the engine drops to idle quickly after a speed pass as Neal suggests. The high end I set so it will keep revving and revving until it hits a plateau without sagging. This involves starting rich and working your way leaner noting the sound the engine makes. As Neal says, the sound of the engine will tell you how it's running and when you attain the ear for it, know what to do based on those sounds. If it revs up and then starts to slow down a little while running WOT, it's too lean. I like to have the low end set a bit richer - such that it will idle and not flame out on transition after idling for 10-15 seconds. The guys that say to set the idle mix so it will idle for 30+ seconds and give a perfect transition likely are setting the bottom pretty lean IMO. Another way to set the idle mixture is to keep leaning the idle (from a rich setting) until it cuts out when you jab the throttle and then richen it back up 1/8-1/4 turn.
When you change the idle stop to change the idle speed, the low speed mixture will be affected. Closing the slide (lower idle) leans the fuel mix and opening the slide richens the mixture, so adjust accordingly.
You can get a fine transition with a 2-needle carb. I usually set my engines so the engine drops to idle quickly after a speed pass as Neal suggests. The high end I set so it will keep revving and revving until it hits a plateau without sagging. This involves starting rich and working your way leaner noting the sound the engine makes. As Neal says, the sound of the engine will tell you how it's running and when you attain the ear for it, know what to do based on those sounds. If it revs up and then starts to slow down a little while running WOT, it's too lean. I like to have the low end set a bit richer - such that it will idle and not flame out on transition after idling for 10-15 seconds. The guys that say to set the idle mix so it will idle for 30+ seconds and give a perfect transition likely are setting the bottom pretty lean IMO. Another way to set the idle mixture is to keep leaning the idle (from a rich setting) until it cuts out when you jab the throttle and then richen it back up 1/8-1/4 turn.
When you change the idle stop to change the idle speed, the low speed mixture will be affected. Closing the slide (lower idle) leans the fuel mix and opening the slide richens the mixture, so adjust accordingly.
the 3rd needle on most of these engines is used to adjust the position of the spray bar in relation to the carb insert...obviously having the spray bar in the ideal position in relation to the incoming air stream can affect the strength of the venturi effect.. So moving the spray bar allows you to maintain the ideal spray bar position in relation to the air inlet when you change the size of the carb inserts... Some racers will run with a 5.4 mm insert and others will run a 9.5 mm insert, being able to move the spray bar accordingly allows us to tune around the venturi size... so pull the spray bar back for a bigger insert and move it inwards for a smaller insert.......... As for changing the transition point...I am not so sure it actually does that...as at every engine RPM there is a require fuel flow...so if you move the spray bar in your also having to move the LSN out accordingly....so no matter where you put the spray bar the LSN also needs to be in the exact same position relative to throttle position ..So your transition point really stays the same in relation to throttle position, so there is no real change...all that changes is the position in the carb opening that the transition happens at.....So as i said already if we use a smaller insert we move the spray bar inwards towards center, and if we are using a big insert we move the spray bar outwards away from center.... Also when we adjust the spray bar we also adjust the LSN exactly the opposite... so if you move the spray bar inwards 1/4 turn move the LSN outward 1/4 turn......
Last edited by supertib; 10-12-2015 at 12:48 PM.
10-12-2015, 02:10 PM
#12
Well, assuming that the choke size isn't being changed, moving the spraybar in towards the center of the choke will increase the demand at the end of the spraybar (discharge orifice) thereby increasing fuel flow. Moving the spraybar away from the center of the choke will decrease the demand and thus fuel flow. If your too rich in the midrange, backing the spraybar out will lean the midrange. True, the low speed may need to be adjusted if you adjust the spraybar. When the spraybar is closer to the center of the choke, the airspeed is fastest thereby drawing fuel better. Further out, the opposite. I'm glad most RTR engines don't have a spraybar adjustment as I think it would add too much complexity for new guys to "get it".
By rights, the choke is the opening above the throttle valve and the Venturi is below the throttle valve. The Venturi effect only works when there is high pressure (large opening) above the valve and low pressure (smaller opening) below the valve.
Know anything about the old Nova BX21 SBK01 engines from way back when? It has a 3-needle carburetor, but I've not used it yet.
By rights, the choke is the opening above the throttle valve and the Venturi is below the throttle valve. The Venturi effect only works when there is high pressure (large opening) above the valve and low pressure (smaller opening) below the valve.
Know anything about the old Nova BX21 SBK01 engines from way back when? It has a 3-needle carburetor, but I've not used it yet.
Last edited by 1QwkSport2.5r; 10-12-2015 at 02:14 PM.
10-12-2015, 02:57 PM
#13
Senior Member
Well, assuming that the choke size isn't being changed, moving the spraybar in towards the center of the choke will increase the demand at the end of the spraybar (discharge orifice) thereby increasing fuel flow. Moving the spraybar away from the center of the choke will decrease the demand and thus fuel flow. If your too rich in the midrange, backing the spraybar out will lean the midrange. True, the low speed may need to be adjusted if you adjust the spraybar. When the spraybar is closer to the center of the choke, the airspeed is fastest thereby drawing fuel better. Further out, the opposite. I'm glad most RTR engines don't have a spraybar adjustment as I think it would add too much complexity for new guys to "get it".
By rights, the choke is the opening above the throttle valve and the Venturi is below the throttle valve. The Venturi effect only works when there is high pressure (large opening) above the valve and low pressure (smaller opening) below the valve.
Know anything about the old Nova BX21 SBK01 engines from way back when? It has a 3-needle carburetor, but I've not used it yet.
By rights, the choke is the opening above the throttle valve and the Venturi is below the throttle valve. The Venturi effect only works when there is high pressure (large opening) above the valve and low pressure (smaller opening) below the valve.
Know anything about the old Nova BX21 SBK01 engines from way back when? It has a 3-needle carburetor, but I've not used it yet.
the choke size is what we change out with the inserts... ( at least I think this is what your saying )
that engine is the grandfather of the P5...
10-12-2015, 04:09 PM
#15
Senior Member
As i say...the mid needle is used to adjust the spray bar position in relation to the sizeof the carb inserts we use ...... bigger inserts we pull the spray bar outwards, smaller inserts we move the spray bar inwards...there is nothing more to it then that. As i say I have done extensive testing with inserts and spray bars, dyno and track tested about everything possible....... even have my own proprietary style of insert that increase fuel mileage ! The NitroMizers !
10-12-2015, 04:57 PM
#17
Senior Member
10-12-2015, 05:15 PM
#18
10-13-2015, 04:41 AM
#19
Senior Member
that was a budget engine so the carb did not have the removable insert...they still used the same body as all the other carbs that had the removable insert..... back then they also had boost bottles hooked up to the engines as well...lots of things they did back then that made little sense or didn't work.... just read that tuning guide, obviously very wrong describing being rich as causing a hanging idle...... In the last 2 decades we have come a very very long way !
