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Old 08-24-2009, 05:51 PM   #16
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Granted .28's are some mean mothers and set-up
properly they tear the tracks up. But I found that
they also wear the hell out of your drivetrain alot
faster. Which means more down time and more money
to keep your rc going.
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Old 08-24-2009, 06:22 PM   #17
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Get a OS .28 XZ. You will not be wrong. Are you sure you need top-end speed as much as on-road? You can torque/power to spin the big wheels on truggy and jumping. Torque is more important to provide acceleration for jumping.

http://www.rc-toro.com/product_info....c3928100e350a2

Also, get OS. Don't get SH, GO ..etc. OS lasts much longer, and more reliable.
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Old 08-24-2009, 07:24 PM   #18
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Originally Posted by megasaxon View Post
Never called you a newb, just saying before you start blowing smoke up peoples' asses, maybe some real results would be a more effective tool for convincing someone, instead of just smack talk.

That being said, i know the JPX .21 is a MONSTER. I've seen them run and no doubt a modded one is just plain silly fast, but to say that is will hands down out perform a high quality .28 is disingenuous at best
I run nasty ass modified .28's.. seriously nasty 28's that I would put against anyone else's with great confidence.. I run them with my DM-1 and they are absolutely smoking fast, easily faster then the .21's, and I can definitely see them rocking in oval racing..... However we are not talking oval here we are talking offroad racing on a offroad track, and I will put everything I know that says no matter how nasty of a .28 you run its going to get chewed by a good .21 on a offroad track surface....... Gear that .28 up all you want and its still not going to help you offroad, in fact gearing up takes away the trigger modulation needed for the infield, and unless you thicken the center your extra power is just wasted out the front end.....

I wish we all lived closer, I would love to see you guys outrun my modified JPX .21 on a track surface with a track setup..... I can definitely make a .28 faster in a Truggy, but it requires gearing up and thickening the center, which kills the machines track performance as well ends up killing the clutch very quickly...... I have experience with many engines and push the limits of performance modding both, and nobody is going to convince me their .28 is going to take down a properly setup .21 on a track surface, sorry it just isn't going to happen..... In fact I would bet money a JPX .21 pulls a stock OS 28 in a 200' straight, and the only way a OS 28 is going to beat it is by gearing up, but by gearing up the OS 28 loses its torque advantage to the wheels and loses throttle modulation in the process......Maybe if you detune the OS28 with a Fiorini clutch or something it may work better IDK... But I have had the second fastest racer in Canada take my OS 28( modified) for a rip and he couldn't do anything with it, it was so violently overpowered it was useless for anything but drag racing or showing off

As I say I own some nasty nasty 28's..Ninja, OS,Nova and Picco.... and on a track surface with modern track tires I will take a modified .21 every single time..... The JPX .21's we run will absolutely smoke the ass off any of the stock high end .21's...HotMod 528 gets owned, Nova 28-7 gets owned, OS 28 gets owned, JPX 28 gets owned..... When I drag mod the 28's they do make alot more power and if setup correctly will be faster , but we can't plant that power on a offroad track surface , its just blows the tires off, if i thicken the center and gear up I can't keep the front end on the ground or turn worth a dam in the corners..... Maybe I run some potent .21's IDK, but for me a .28 is useless for the track....

Maybe this week if weather permits I will shoot some drag race videos on the dirt of .21's vs .28's.....
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Old 08-24-2009, 07:29 PM   #19
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I'd have to say it all depends on a particular .21 and a particular .28 one is talking about. I would not just claim that .21's are faster than .28's on top end period. Here's an example:
Tuned GRP .28 engine - RPM redline is 43,000
Tuned GRP .21 engine - RPM redline is 43,000
Picco .21 P7 EVO 3 engine - RPM redline is 30,000

I realize the GRP's are turbo but still.

you must realize that a manufacturers claimed RPM and HP figures mean nothing.... So the numbers you posted in no way shape or form reflect how much RPM these engines will pull in real life conditions....put a GRP .28 next to a EVO 3 with the same gearing and watch what happens !
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Old 08-24-2009, 10:19 PM   #20
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As always, some good points made by all sides. From my years of building and racing these things, I have found that it really comes down to personal preference. While alot of today's .21's will have more than enough power and low end torque to move a truggy out in a timely fashion and as Max stated, will get the power to the ground efficiently and on alot of surfaces will have better forward acceleration due to more efficient power delivery. As far as a .28 not having more rpms is not always true. I have raced with megasaxon personally down in PA and he has personally watched my Nova Plus28-7T with my standard race port circle the track in a very timely fashion and with the proper tire selection, it was laying the power down very efficiently for a modded .28. But with more torque comes more clutch and gearing setup. Most stock gearing in truggies are up in the 15+:1 ratios where the buggies hang around the mid 11's somewhere. Add in the added torque but with increased tire diameter, do the math and select the proper ratio. As Max also stated, the bigger engines are harder on clutch shoes, bearings etc. so a little more maintenace is in order when running the .28's. Some of my fastest engines have been built out of .28's and i also have done alot of side by side testing in the same vehicles with same clutching and gearing and from my experiences with my own engines, my .28's always prevailed everywhere as far as power output and rpm. On some tracks, a .28 will be a better suited engine ansd some tracks, a nice .21 is the best choice. some of my team drivers have run both sized engines in their vehicles and have reported back with similar opinions. There are always 2 ways to skin a cat so this is in no way me telling anyone what is best, just stating what I have found with my engines, in my environment. I do alot of traveling and I always run a .28 in my truggy and never have a problem with too much power. It just takes a little different approach to setup and operation of the bigger engine. I run .9's in my truck with stock gearing or 1 up on the bell depending on track size and conditions. Sometimes I get more wheel spin out of the corners than someone running a .21 but there are areas on the track that a .21 just won't always cut it that i make up the ground needed to stay competative. Last but not least, it depends on driving style as well. I drive like Ryan Lutz with my truggy so the .28's go perfect with my style and I have been to tracks were my .28 engine will clear triples and quads that a .21 falls short on also making up some lost ground so as I mentioned, will depend on what you think your driving style will support and what the track will allow. I'm sure this converstion will continue on course and it is always good to discuss things with each other. Just remember these are only opinions so no need to get all fired up over it. the way i look at it, if what you do works for you, then great!! If you want to share with others, thats cool but don't think that what you do is gospel and everyone else is wrong for what they use and how they use it.

For the guy who originally asked the question, if you feel a .21 is the way you want to go, my recommendations would be a Nova P5, Plus 4, Jammin JPX .21 or something along those lines. If you want a good running .28, the Nova Plus28 series is good for the money, a Picco P3-28 is decent as well. The Plus28-3 is a great engine for the money but will need some more blowdown timing to get the upper range performance out of it. The Plus28-5 is decent all around but also will gain performance with some port work and the Plus28-7 is great as is and is even nastier race ported. The Picco P3-28/jammin JPX .28 is wicked with a race port and it actually requires a nice port job to get the run time and tunability out of it. The stock engine can be finiky and run times are not very good due to the low end needing more fuel than normal to compensate for original engine design. Run times on all of my .28's have ranged from 9-11:30 minutes after mods depending on pipe, tune, climate etc.
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Old 08-24-2009, 11:06 PM   #21
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As always, some good points made by all sides. From my years of building and racing these things, I have found that it really comes down to personal preference. While alot of today's .21's will have more than enough power and low end torque to move a truggy out in a timely fashion and as Max stated, will get the power to the ground efficiently and on alot of surfaces will have better forward acceleration due to more efficient power delivery. As far as a .28 not having more rpms is not always true. I have raced with megasaxon personally down in PA and he has personally watched my Nova Plus28-7T with my standard race port circle the track in a very timely fashion and with the proper tire selection, it was laying the power down very efficiently for a modded .28. But with more torque comes more clutch and gearing setup. Most stock gearing in truggies are up in the 15+:1 ratios where the buggies hang around the mid 11's somewhere. Add in the added torque but with increased tire diameter, do the math and select the proper ratio. As Max also stated, the bigger engines are harder on clutch shoes, bearings etc. so a little more maintenace is in order when running the .28's. Some of my fastest engines have been built out of .28's and i also have done alot of side by side testing in the same vehicles with same clutching and gearing and from my experiences with my own engines, my .28's always prevailed everywhere as far as power output and rpm. On some tracks, a .28 will be a better suited engine ansd some tracks, a nice .21 is the best choice. some of my team drivers have run both sized engines in their vehicles and have reported back with similar opinions. There are always 2 ways to skin a cat so this is in no way me telling anyone what is best, just stating what I have found with my engines, in my environment. I do alot of traveling and I always run a .28 in my truggy and never have a problem with too much power. It just takes a little different approach to setup and operation of the bigger engine. I run .9's in my truck with stock gearing or 1 up on the bell depending on track size and conditions. Sometimes I get more wheel spin out of the corners than someone running a .21 but there are areas on the track that a .21 just won't always cut it that i make up the ground needed to stay competative. Last but not least, it depends on driving style as well. I drive like Ryan Lutz with my truggy so the .28's go perfect with my style and I have been to tracks were my .28 engine will clear triples and quads that a .21 falls short on also making up some lost ground so as I mentioned, will depend on what you think your driving style will support and what the track will allow. I'm sure this converstion will continue on course and it is always good to discuss things with each other. Just remember these are only opinions so no need to get all fired up over it. the way i look at it, if what you do works for you, then great!! If you want to share with others, thats cool but don't think that what you do is gospel and everyone else is wrong for what they use and how they use it.

For the guy who originally asked the question, if you feel a .21 is the way you want to go, my recommendations would be a Nova P5, Plus 4, Jammin JPX .21 or something along those lines. If you want a good running .28, the Nova Plus28 series is good for the money, a Picco P3-28 is decent as well. The Plus28-3 is a great engine for the money but will need some more blowdown timing to get the upper range performance out of it. The Plus28-5 is decent all around but also will gain performance with some port work and the Plus28-7 is great as is and is even nastier race ported. The Picco P3-28/jammin JPX .28 is wicked with a race port and it actually requires a nice port job to get the run time and tunability out of it. The stock engine can be finiky and run times are not very good due to the low end needing more fuel than normal to compensate for original engine design. Run times on all of my .28's have ranged from 9-11:30 minutes after mods depending on pipe, tune, climate etc.

Very well put Mark !

I can definitely see how each of us has a point..we all are doing things differently and are running in different conditions....I guess matching the engines powerband as closely to the conditions is the key, whether its a .21 or a .28....too much power hurts, and so does too little power....having it just right is the key

Right now the Hot ticket from my camp is a modified JPX .21, .9 springs, 086 pipe.. stock gearing on high bite, up 1 tooth on slick.... Many times we get asked what .28 we are running as the engine hits so hard, we have never come across any triple or track obstacle we couldn't make.. Nor have we ever come across an engine that could pull on us, nor have we come across another engine we couldn't pull. If we are beat it is by a better driver.. We race in Alberta, Saskatchewan, Manitoba and Minnesota and North Dakota so far, but are hoping to travel out further... I am not trying to say a faster engine doesn't exist, just that so far we have never seen anything that matches the Mod JPX in acceleration or speed...we mainly run Losi 8T 2.0..our runtimes range from 8 -11 minutes depending on track and conditions.......As I say I do own some nasty modded .28's, but they are so overkill there is no point in us running them, we get more then enough pop from the .21 that the .28 just isn't needed ...... With the modern Truggies getting lighter and easier to push, the .21's just seem to work better for us...my Mugen 5T does better with a .28, but the 6T,2.0 and X2 just seem to be too overpowered with the .28's....Maybe I should try to tame the bottom more on my .28's IDK, but my current ones are useless for racing at any of the tracks we have cone across so far... Tho I do love the .28's, I just can't find the sweet spot for racing them......
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Old 08-25-2009, 12:07 AM   #22
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Not sure how far you go with port timing, but I have found the big blocks like more exhaust timing than a .21. With most .28's being a .21 converted, the case volume is very close and with the bigger stroke and/or bore depending on the make of engine, the velocities are alot higher in the .28 which gives them more case pack and cylinder fill during the power stroke and induction duration. It could be looked at a couple different ways. You could look at it as the case is borderline too big for a .21 to have that snap and the case is just right for a .28 as far as total velocities are concerned or you could look at it as the case volume is just right for the .21's and too small for the .28's which is why the velocities and pressure/vacuume are so high resulting in an extremely responsive but finiky tuning engine. As you work on engine to engine, you find engines with bigger volume cases than others which from my experience gives the engine alot of it's running characteristics. The Picco's always had smaller case volume which the .21's definately benefited from but the .28's needed volume added to make them tune and perform properly. A .21 that can breath will almost always outperform a bigger block that can't. A stock Picco P3-28 has too little blowdown and not enough crank timing and case volume to perform and tune correctly. I mean you can get it to run decently, but it definately lacks the broad tuning window one would desire from any engine. The more forgiving the tuning window, the easier your life is and by degreeing the engine and setting the perameter's to your desired outcome will give it what you would expect from a long stroke big block. I have added as much as 15-17 degrees of blowdown timing on those engines and that is where they ran the best. Add a few auxillary ports to add case volume and slow velocity a little and you have a very smooth but very strong engine that works well on most tracks. The P3-28 stock has 20 degrees of blowdown and I run mine around 35-37 degrees with 3 auxillary ports and paired with a JP1, it definately rock and rolls. Everyone has different ways of measuring and degreeing in engines so whatever method works for you Max, stick with it. I would have to remeasure the sleeve but I believe I lift the exhaust port about 1.5-2mm's from stock and make sure the exhaust boosters open the same time the main port does for maximum exhaust port surface area. You will have to port match the case when you lift the ports that high. It sounds like alot of material coming out and it is but it WILL support it!! Be careful not to over grind the case as you will blow through the side of it The picco .21's have 25 degrees of blowdown stock which is a big reason why they run so good out of the box. Most engines have between 18-20 degrees in stock trim. I run my .21's between 23-27 degrees where my .28's are usually 32-35 and they love it!! Give it a try sometime and let me know what you think of that much timing. If you have tried that already, I'm just preaching to the choir then
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Old 08-25-2009, 06:53 AM   #23
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Great posts Mark! I think you are right that it really does depend on the track and driving style for the .21 vs .28 discussion. Just seems that my track (oakhill) has always been dominated by the .28s, especially the OS. And when i put one in, i had a HUGE smile on my face. My truggy was able to make up ground where the .21s couldn't, and i run my RC8T with a lot of rear brake, spike it and punch the throttle and with I-beams in the back and citty blocks up front, the thing grabs hard and moves forward when i want it to, with minimal wheelspin. When i get my Reedy fixed(long story) i'm gonna put it back in and try a few things with it, i know i didn't have it setup perfectly, but i'm sure from the preliminary tests i did, it'll be a pretty good power plant, with excellent run time. Better then my OS .28? IDK, but i think i can win some races with it...
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Old 08-27-2009, 10:50 PM   #24
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man 28's are the sh$% i have a PICCO 28 P3 modded bi POWERHOUSE . LEt me tell you this thang is OFF THE HOOK!!! not only do i have more bottom thatn any body esle i jump up one tooth on my bell can't nobody hang with me on the straight!!!!!!!!!! IF YOU WANT SOME COME GET SOME......
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Old 08-28-2009, 12:44 PM   #25
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Default .21 vs .28

I am still running the GRP TUNED engines. I run the .28 for trug & .21 for buggy. One of the tracks I run on has about a 220' straight and I notice as I am exiting the sweeping turn before the straight with my .28 I have to slowly roll on the throttle before hitting the straight to keep from going broad side for 30 feet down the straight. I have followed many .21's throught this part of the track and the .21's are able to get on the power quicker and pull a few feet away, but by the time we're 1/2 down the straight more times then not I am side by side and then run out of top end. I choose to run the .28 because I can use inside lines roll on the throttle and clear doubles with ease and when a track is wet with good dirt I always have a big smile.
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Old 08-28-2009, 01:46 PM   #26
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I am still running the GRP TUNED engines. I run the .28 for trug & .21 for buggy. One of the tracks I run on has about a 220' straight and I notice as I am exiting the sweeping turn before the straight with my .28 I have to slowly roll on the throttle before hitting the straight to keep from going broad side for 30 feet down the straight. I have followed many .21's throught this part of the track and the .21's are able to get on the power quicker and pull a few feet away, but by the time we're 1/2 down the straight more times then not I am side by side and then run out of top end. I choose to run the .28 because I can use inside lines roll on the throttle and clear doubles with ease and when a track is wet with good dirt I always have a big smile.
Try going to a softer spring selection, this will allow the motor to ingage at a lower rpm, and it should allow you to apply power sooner, and will help revive some of the topend, or just go up a tooth on the bell. Or just look into the OS 28 as your next motor
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Old 08-28-2009, 03:37 PM   #27
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very positive this tread was starting to get real ugly real fast glad everyone could come to an agreement
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Old 08-28-2009, 05:10 PM   #28
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newer breed truggy's Do Not need a .28.....imo all your doing is blowing out your drive train/clutch and wasting tread on tires.

.21's are the Ticket No doubt


How many top 20 worlds driver's rock .28 ?
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Old 08-28-2009, 05:34 PM   #29
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how about we split it down the middle an try this http://www.amainhobbies.com/product_...ine-Turbo-Plug
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Old 08-28-2009, 05:35 PM   #30
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my rb rt28 can blow the doors off $500 21's all day . only losses at the gas pump.
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