1QwkSport2.5r

I picked up a NIB Nova short stroke .21 modified by Ron Paris that needs a home and an exhaust system. Thought about Ofna; maybe a Hyper 7 or Ultra LX. But I have NO clue on the exhaust. Based on what I've been able to find out about this engine, being a short stroke engine, it revs quick. Designed to really haul the mail out of the corners. So what exhaust system will make it really shine? It is an off-road engine and will be used on and off road. I'll be running it on 30% nitro.

Any help would be appreciated. Any other car suggestions are welcomed as well.

collector1231

My Feedback: (1)

OFNA seems like a nice choice. LX2 is one of the the best model I've seen of theirs.

1QwkSport2.5r

I've wanted a buggy for a long time and for a basher, Ofna always gets mentioned. An old forum admin I used to talk to had the original Ofna ultra LX comp, the precursor to the LX1. It was fast, agile, and tough. That's probably what I'll be goin with. Probably going to try to find a roller since I have an engine. I just need the right exhaust system.

Cool_cris27

For exhaust it depends is it a rear port on the engine? or something else?

1QwkSport2.5r

It's a rear exhaust engine like 95% of all other car engines. I already have a buggy header (and a monster truck header too) but I don't have the right muffler for it. This is not an engine you throw any old pipe at.

Cool_cris27

hmmm so your putting this in a 1/8 scale right? well Generally any pipe for off road vehicles that says 1/8 should fit almost all 1/8 buggys/trucks but its a .21. So i think any pipe should fit that .21 if it says 1/8 on it because most 1/8 pipes fit .21-.28. But another questions how much are you willing to spend?? you can spend from 30-150+ on a pipe Ill give you a cheaper one and a more expensive one too look at to see what you could get with your money here. Also!!! do you want low-mid power? or mid-top power? So basically thats better Low to middle end speed or Middle to top end speed. Certain pipes increase your engines power at certain points but if you get crappy exhaust t could make your engine weaker.

http://www.losi.com/Products/Feature...rodID=LOSR8001
This is somewhat a cheaper one but not a bad pipe its an Ok pipe for 60 dollars a litter over priced i think but for 60$ its ok. If you want to go big buy this!
you should get a custom made one for like 120-140 there absolutely insane heres a link
http://www.extremercmods.com/pipes

phmaximus

What about a losi 8ight 2.0..... Since the release of the 3.0 they are only getting cheaper...

I've seen a few ex raceing ones for sale very cheap.... (I brought one, for $150 missing the motor) I suspect there are a few guys upgrading to the 3.0 and selling of there 2.0
sure the ballends and diff yokes are a bit worn. But that's easy to fix... And cheap

1QwkSport2.5r

We are not dealing with a $175 LRP or HPI or $140 Traxxas engine here. You can get mediocre performance with whatever pipe you have, but certain engines are tuned for a more specific purpose (powerband) and some pipes specifically address these areas. As I understand it, this engine was specifically tuned/modified by Ron Paris to his own specs which means a pipe you'd use on the regular version of the engine may work fine but on the modified version may be a total waste. I hear all of these numbers thrown around (053, 086, etc) but know so little (since I'm not a racer) about them that if I'm going to drop $75-125 on a pipe on an engine that costed 3 times that, I want it to be the right one right off the bat. I do not believe a pipe designed for a .21 will work as effectively on a .28, especially a "fast" engine like a Nova.

For or those that know, what do the 3 digit pipe numbers stand for, and does a high rpm pipe wake up a mid rpm engine or would a mid rpm engine get a mid rpm pipe just because? The short stroke Nova I have is designed and ported for insane power coming out of turns. It's said to be a crazy fast revver and is considered a low-mid rpm engine. I think the listed top rpm from Paris Racing is 34,600rpm with the 7 port version eeking up to around 36,000rpm. I would have gotten the 7 port version but I didn't have the extra $50 they wanted for it.

What I have not been able to find out about this engine is what specifically is done differently in the Ron Paris version of the BX21 SBK versus the standard BX21 SBK. Also, does anyone know if the boost chamber (which is said to have no performance advantages) can be removed from the backplate?

1QwkSport2.5r

I am a big Losi fan, I'll look into that one too. They're all bump-start these days, right? This Nova is bump start only. Have not found a pull/roto start backplate and crank for it which isn't too surprising.

Cool_cris27

Well maybe you should look for a custom made exhaust for your engine and its modifications. You go to extremercmods and you email the guy and you can tell him everything he needs to know to make the perfect exhaust might cost like 150$ TOTALY worth it In my opinion.

Anthoop

Without someone having experience with that particular engine (with mods) and having the knowledge of trying different pipes on it, then I think it will be very difficult to get the perfect pipe for it and how you use it with one shot.
The numbers (generally) refer to the size and shape of the pipe...so in effect the numbers give a gauge to how it will perform.
I am a bit reluctant to say X is the pipe you need because it would be a guess...but I will say that the Dynamite 053 and 086 are $50 a piece (looking at US Ebay), both pipes will "work" and with testing you will decide which is best suited. Sure if you had a hundred different pipes to hand then you may find one that suits the engine and you better but those two will cover a wide spectrum of needs at a reasonable price.

As for the boost bottle- Looking at pictures of the BX21SBK online....it could be either screwed into the back plate or maybe a press fit. Personally I would leave it on there, if you do not want it connected then remove the nipple (below carb.) and block the hole with a screw and a fibre washer or dab of sealer....
Some of the Hyper engines have a similar set up but the bottle is screwed to the backplate using the backplate screws...I have tried a back to back test with the bottle connected/disconnected and if there is a difference then it is far to small to tell...but the principal is sound and I know it works on larger engines.

On the subject of which buggy...my choice would be the Hyper7...tough as old boots, cheap, full spares available (and will be for along time yet).

1QwkSport2.5r

I just assumed the racer experts here would have some knowledge of these 'rare' engines being that Ron Paris and Paris Racing was so legendary. Seems as though he and his company was well known but what he did or had done with the engines is a different story. Someone I'd gotten an aircraft engine from awhile ago has a Ron Paris on-road Picco and he said it was a real strong runner.

No doubt Ron had good taste in engine manufacturers, but I think some of his instructions that came with the engine left some to be desired. Then again this engine was made 13 years ago and the instructions were written 15 years ago.

Anthoop - I totally understand not being able to suggest one option over the other, I'll keep my eyes open and keep scrounging the internet for what info I can find about this engine. I'm seeing, or it seems anyway, that Novarossi doesn't make any one model of engine very long so that makes sense as to why I don't see much info about them. They make so many different engines all for the same or very similar purpose; that surprises me yet makes me wonder why...

I wonder if a top rpm pipe would balance the short stroke mid-rpm power and let the engine wind up a tad more?


It does sound like though, that some parts from the modern engines will fit the older ones. The R7 conrod (the successor to the rod in the BX21) is said to fit (and be a slight upgrade over the old unit) as do some of the newer Piston/liner sets. Though I doubt I'd ever need to rebuild the engine, it's good to hear there's a possibility that current parts may fit.

i8tweety

My Feedback: (11)

I've found the best results on my high rpm .21 race engines (OS, RB, Rossi, Paris Picco, etc) mating them with the RB 9886 pipe.

Anthoop

If I had to take a guess then I would go for the 086...for the reasons you mention.
Yes Novarossi do make alot of engines...and every year there is a new batch...with different this/that and the other...but as you say many parts will interchange with others and they are all for a similar purpose. If we are honest, not much has changed from your 15 year old engine to the current engines, just minor details change...but who would want to buy an engine that was designed 15 years ago when CarlosFandangoEngines have just bought out a "new" engine!!! That is why a company like Novarossi (and all the rest) constantly bring new engines out.
As for knowing what was done to the engine...then that would be impossible to know unless you take it apart and look and measure whilst comparing to the standard BX21SBK. Not many (if any) engine modders will tell you exactly what they do to an engine...there is virtually zero chance of finding the information from a current modder, let alone one that has past.

The 9886 will have the same dimensions as the 086.

1QwkSport2.5r

I didn't expect to find out what was done to it specifically. I basically was hoping to find out if it was pulled off the shelf, some Xeroxed instructions added, slap a racing companies' sticker on it and sell it, or was it really modified? I'm seeing no evidence it was modified unless the liner was re-plated. I pulled the head and liner off/out and there is chrome on the outside of the ports. There's no evidence of any work done on the ports as the guy at the hobby shop claimed there was. Perhaps Paris Racing installed a new piston and liner made by them? I'm glad I pulled the head off as I found swarf in the head button and some crud under the carb. Not a good thing to find swarf!

Ill look at grabbing a 086 pipe then. I think the hobby shop has one so I'll grab one next time I'm over that way.

collector1231

My Feedback: (1)

Crap, I looked up swarf. Found out my HPI Firebolt motor leaks it like heck.... Darn. Thought it was just dirt. Nope. The motor is eating itself!

Anthoop

No chance it would have been re-plated or a special liner...if the sleeve/liner has been altered then you should be able to see...especially mods from that era...
If I ever found swarf in an engine I would kinda feel like I had won the lottery....suffice to say I have never encountered it.

1QwkSport2.5r

Here's the head button picture. If I had a macro lens for my camera it would be much easier to see. It was magnetic which made it that much stranger being out of the aluminum head button.

I have found swarf only in a couple of engines and what I did find was minimal. It never hurts to open a new engine to have a look. I've made that standard practice as I'd not want a brand new engine to pump that crap through it.

I took pictures of what I took apart as I pulled it down, literally.

phmaximus

Well it defiantly sounds like u have a nice engine...
So does that mean there is no current recommendation of what pipe to use?
...just wondering what did u want from it? Fast bash car? Track car? High speed car? Because I'm thinking that the pipe will be really determined on where and how u are driving it. Because if u are bashing in small areas or are bashing on a tight track u might find u need a bit more low end torque.... Where if u are just doing speed runs down the street and in big ovals u might want something more suited to top end??
but then again I really have no idea on pipes... The are one of those things where the difference from a good to a great pipe is unnoticeable unless u are timing consistent laps.

with my limited knowledge of pipe I would look for something in the ballpark that's cheap. Then use that as a base line for testing other pipes

Anthoop

Yes, I always take an engine apart before running also. It has definitely helped in your case...you would not want that floating around in there.
Did you measure the timing?

1QwkSport2.5r

In a nutshell, I'll end up with a fast basher. If I do any racing it's not going to be anything crazy. No tracks anywhere near me and with my schedule, I'd have little time for it anyway. The idea is the engine revs quick on the low side and on the high side the pipe takes over and gives it a little more oomph up top. Maybe enough to be a Jato killer?

No I haven't degreed/timed it yet and the photos of the liner turned out fuzzy. It definitely shows no signs of aftermarket modifications as far as I can tell. Also, I cannot get the conrod off the crankpin so I cannot look at the crank or piston any closer either. Nothing is gummed up, I think the tolerances are just that tight that I'll likely have to heat the crankcase up to get the rod off.


Ill try to get some numbers and new pics later.

1QwkSport2.5r

For those interested, here's pics of the liner. I started with the boost port and worked around but they didn't upload in that order. I usually don't see chrome on the outside of the liner in the ports like you can see in these photos.

phmaximus

Hey that's a though u could get a jato darn cheap...

http://www.ebay.com/itm/Traxxas-Nitr...item35d3ec92ad

http://www.ebay.com/itm/traxxas-jato...item258b82a751

1QwkSport2.5r

Already have a Jato, I brought that up in the engine thread in the car engines forum and a guy called the Jato a "pedestrian r/c". In the grand scheme of things, it'd be a waste of this engine in a jato because it'd spend more time on its lid. With a little more weight and 4 wheel drive, maybe. A 4wd jato sounds fantastic but I don't have the means to make new parts. That's a project I'd build if I had the means. A 2wd Jato is fast, a 4wd Jato with a fast .21? I could only imagine.

Anthoop

Maybe the sleeve is standard then and just a crank timing alteration...one would hope there has been something altered and not just a label/name added to sell it.
Did you try a cable tie around the rod to get it off?