I race nitro truggy and have quite a bit of experience with the P5 as well as the higher end 7 port engines. Novarossi has refined the P5 based engine over the past 10 years and the result is the current P5XLT. I do not believe they allocate much R&D towards this platform as compared to their high end engines. The BTT/Bonito and now the Keep-Off engines leverage newer technology which requires more R&D as well as testing to keep them on the cutting edge. This combined with some noticeable upgrades such as the weighted crank, ceramic bearing(s), lower CG head, etc. understandably increase the cost.

Is there a difference on the track? Absolutely. In my Serpent 811TE truggy the P5XLT while strong does not have the top end compared to the Bonito or Keep Off 21-7. However with that said, there's probably only two tracks I race on where that extra RPM can be leveraged to a distinct advantage. Most would agree, more powerful engines can be detrimental to many off road racers so any comparison should take track and driving style into consideration.

Are the higher end engines worth the extra coin? Well I think that would have to be in the eyes of the beholder. As you can appreciate, every racer has their own opinions. I prefer the higher end engines though I'm blessed my driving experience and budget 'justify' the extra coin. Nonetheless some good friends of mine have done very well at some big races with a box stock P5XLT with the 2096/021 combo.

Thanks for the reply. I have been using the p5xlt with a Dynamite 007HT pipe and header(just because that's what I had) and I've been to a few bigger tracks where it really gets opened up. I have yet to see a car that would run away from it. Bottom or top end. Granted I'm still pretty new and my driving probably just isn't good enough to realize the benefits of a better engine yet.

Hi ron yeah I was thinking that too after i posted this. Who ever had engine before took a dremel to the bottom of it and grinded off the cooling fins on one side of the front end. thanks again Michael

well said about the engines.

In my opinion the p5 is the best engine ever made. I run buggy only and the 4 and 5 ports seem to be ideal. The 7 ports I've had were blazing fast but never had the power directly off bottom the p5 had and were not as easy to tune, no one seems to agree. I guess I don't exactly know what they need. I have a pretty dirty collection of 4 and 5 port novas. If I had to pick one engine to run it would be a pimped out p5. For a smaller track the stock engine is perfect, but on a good sized track the clocked p5 has bottom like I'm used to and an awesome power-band that makes me a bit more cautious but has the goods. I still wouldn't say anything bad about a BTT they have a bit more updated build quality and the clocked BTT is just about the most consistently easy to drive superfast engine I've come across. So yeah, some engines cost more and are worth it and some really are not. I tend to like the less expensive engines with all the special things done to them over radical designs that may not be as reliable.

Well said Mad Dog. I kept the context of my discussion between the stock P5XLT and the higher end BTT/Bonito/Keep Off engines. I would tend to believe modified P5 based engines by HES and CRE bridges the gap nicely. Truth be told one of the finest performing engines I've ever driven was a Houston Team P5XLT. Unfortunately its life was cut far too short due to a ceramic ball disintegrating in the main bearing but that's a story for a cold winter day.

In all, great discussion...but either way one cannot go wrong with any of the options, they're all Novarossi engines.

Ok you guys what a ball park needle setting for a p5xlt on 30
Would it be flush and flush

Close for starters, yes I am about 1 turn in on both with a .5mm idle gap. Temps 230, 10 min tanks with an Re12 , nova 6 plug.

So with the keep off .21 being out for a racing season what is everyone's impression on it? Tune ability, run time, durably? How is the run time compared
To a btt? Thanks -Tim

So with the keep off .21 being out for a racing season what is everyone's impression on it? Tune ability, run time, durably? How is the run time compared
To a btt? Thanks -Tim

Well, I haven't run it, but it should be more or less the same.. sleeve is the same, piston, crankshaft same..
Only real difference would be the larger rear bearing and crankcase. I'm no expert on that, some people say a different crankcase can make a big difference. I just think it's more or less the same sort of engine, if there's anything to these claims of spooling up quicker due to a larger bearing, the difference won't be too large.

Hey mate just ran the Townsville cup last month 6tr with the p5xlt 9853 pipe on 30% nitro x99t plug was half turn in on hi set and just in from flush on the bottom I felt there was a bit more but played it safe
Cheers

Hello everyone, I'm a begiiner in 1/8 onroad competition, and would like to hear your opinion abou Kappo .21 engine
http://www.novarossi.it/2012/index.p...c/kappo21.html

Will it be enough? My track is a medium to long track, I'm not a very experienced driver but want a motor to make good results.

Here is a video of the track -> http://www.youtube.com/watch?v=CslJnRo5eaM

So guys, question..
Have I diagnosed this correctly if I think it is a leaky front bearing?

-P5XLT engine freshly pinched, only break-in done, new conrod, good crank
-irratic idle, sounds like motorboating "woooorrr wooorrr wooorrr" rather than one continuous stable sound
-at first engine ran fine, but towards the end of the day kept choking, despite being ran sufficiently lean
-seems to be carburated fine, but then after 1/4th lap on the track chokes for no apparent reason
-engine has truckloads of compression obviously
-front bearing is cheapo €4 ebay bearing

I'm thinking this means the cheapo front bearing has let go? Even if it has only less than 1 gallon on it.

This is the off-road forum you are asking in. I am sure some of the guys on here race both, but you might get a broader opinion asking in the on-road forum

whoevers idea it was to put one of those cheap ass ones off of ebay on there it was a bad one

an engine wont tune in worth a crap if it has a bearing you can see daylight through

check hsn for blockage also while youre troubleshooting