ESP G340 vs OBR G340 reed

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Sean

The way I try to explain it to customers is you need to look at overall picture of a graph. These will be just made up numbers as an example. You look at a dyno graph and it making 12 hp. You see another one only making 10 hp. Now keep in mind a graph that looks like an upside down "V" is useless because power band is so narrow. We had a pipe we built once. Made the most power BUT the powerband was only like about 1000 rpm either way. So this means you fall off the powerband either side it takes forever to get backup to power again. Now if you have a power band that is more flatter looking. Yes it may not have the peak big number but you can have a more forgiving setup. Same thing with using a engine designed for topend only and you doing short course track racing. Yes. IF you have a long enough straight you can outpower the other guy. But. If it is a tight course or a lot of turns? More of a mid lowend engine may be better suited because of the flatter torque on pulling out of the corners. Think of your saws. Probably around maybe 8500 rpm or so is the norm with a powerband that you can bog on in heavy cuts. Now take same cutting but a motor designed for top end only. Unless you going to say keep it above 12500 rpm or so with light cuts. The first time you push it hard it will fall off pipe or muffler and be a dog. Than you have the pipe itself that comes into play. Topend pipe on torque engine or vice versa is not good. Has to be a package to work together optimumly. There of course is more on this kinda stuff but should be at least a rough idea. Using a dyno is fine. As long as the dyno is calibrated correctly. They will all read either same or really close. We had two other people who dynoed the same engine we sent to someone. Both were in totally different areas and elevations. One guy read 1 tenth higher and the other guy read 1 tenth lower than ours. They setup their way on calibrating the dynos. We had someone who ran an inertia dyno tell us how it made more power when you lightened the flywheel. He was on an inertia dyno where you spin the weight up and so much time will make so much power etc. When we asked if he recalibrated for the lightening of the flywheel? He got quiet when we told him it will of course show a power increase because it is spinning less weight quicker. BUT is still set for the heavier weight it had before. The other thing is rpm and where power is made. Let say 12 hp at 12,000 rpm and once you get into the over rev area you have 4 hp at 19,000 rpm. Now take an engine that makes 10hp but now has torque through whole powerband and had 8 hp at 19,000 rpm. It will be faster because you have more power available on topend and if you are never at the 12,000rpm area? Than the power there is useless to give up where you need it higher up. Keep in mind though that we make our engines and the cylinders also. So we can have the optimum in port layout compared to an industrial style engine. People ask me why I don't talk bad about the zen engines like they do about ours. That is fine but we do not knock them. They are built for something else and than modified and run really good. Where ours is purpose built. Plus if a customer asks me a question and I do not know the answer. I will just flat out tell them. I would rather someone think that guy doesn't know the answer. Than to BS the person and than them find out I had no clue. Better to say you don't know than to bs and than it is worse than just not knowing.
 
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TODD said:
Sean

The way I try to explain it to customers is you need to look at overall picture of a graph. These will be just made up numbers as an example. You look at a dyno graph and it making 12 hp. You see another one only making 10 hp. Now keep in mind a graph that looks like an upside down "V" is useless because power band is so narrow. We had a pipe we built once. Made the most power BUT the powerband was only like about 1000 rpm either way. So this means you fall off the powerband either side it takes forever to get backup to power again. Now if you have a power band that is more flatter looking. Yes it may not have the peak big number but you can have a more forgiving setup. Same thing with using a engine designed for topend only and you doing short course track racing. Yes. IF you have a long enough straight you can outpower the other guy. But. If it is a tight course or a lot of turns? More of a mid lowend engine may be better suited because of the flatter torque on pulling out of the corners. Think of your saws. Probably around maybe 8500 rpm or so is the norm with a powerband that you can bog on in heavy cuts. Now take same cutting but a motor designed for top end only. Unless you going to say keep it above 12500 rpm or so with light cuts. The first time you push it hard it will fall off pipe or muffler and be a dog. Than you have the pipe itself that comes into play. Topend pipe on torque engine or vice versa is not good. Has to be a package to work together optimumly. There of course is more on this kinda stuff but should be at least a rough idea. Using a dyno is fine. As long as the dyno is calibrated correctly. They will all read either same or really close. We had two other people who dynoed the same engine we sent to someone. Both were in totally different areas and elevations. One guy read 1 tenth higher and the other guy read 1 tenth lower than ours. They setup their way on calibrating the dynos. We had someone who ran an inertia dyno tell us how it made more power when you lightened the flywheel. He was on an inertia dyno where you spin the weight up and so much time will make so much power etc. When we asked if he recalibrated for the lightening of the flywheel? He got quiet when we told him it will of course show a power increase because it is spinning less weight quicker. BUT is still set for the heavier weight it had before. The other thing is rpm and where power is made. Let say 12 hp at 12,000 rpm and once you get into the over rev area you have 4 hp at 19,000 rpm. Now take an engine that makes 10hp but now has torque through whole powerband and had 8 hp at 19,000 rpm. It will be faster because you have more power available on topend and if you are never at the 12,000rpm area? Than the power there is useless to give up where you need it higher up. Keep in mind though that we make our engines and the cylinders also. So we can have the optimum in port layout compared to an industrial style engine. People ask me why I don't talk bad about the zen engines like they do about ours. That is fine but we do not knock them. They are built for something else and than modified and run really good. Where ours is purpose built. Plus if a customer asks me a question and I do not know the answer. I will just flat out tell them. I would rather someone think that guy doesn't know the answer. Than to BS the person and than them find out I had no clue. Better to say you don't know than to bs and than it is worse than just not knowing.
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Right mate ??. Peaky engines suck. We build saws much the same way, shoot for long torque curve and the hp numbers kinda are what they are, of course the rpm range is quite a but different between a 40cc and 80cc but same principal applies. Thanks for the response mate, I think that cleared up a few things for me at least.
 
I just asked the OBR UK division how willing the full mod G340 Reed V2 is to rev on 17/57 gearing and was not really given an answer, despite asking - more than once.

The responses were from a nameless person who merely pointed out that "I didn't want to run 17/57 gearing".

Thanks for pointing out what I want.

Then I was told that I need to stick with what I've got - my 15 year old Fuelie engine. Which as it stands, still goes rather well - 19300 RPMs and 49mph on 17/57 - but that's hardly the point.

Screenshot_20240831-114743.png

Not once did I get an answer to the question I asked - ie - how willing is this engine to rev.

What I got was a gear ratio 'I'd prob run' from out of a hat, without any knowledge of where I was running, or on what surface, or what altitude! 😝

It seems a very strange way to do business.

It's a shame, because I was thinking of bolting one into this:

PXL_20240817_145154573.MP.jpg
PXL_20240811_174844186.MP.jpg
But apparently, they 'know' what I need.

Bartolone it is then....🤣

I'm now trying to get some sense out of the US OBR, in the vain hope that it's someone different. 🤞

Screenshot_20240831-120518.webp
 
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It's going to pull about the same rpm, just get there faster. You're already under geared hitting 19k with the weaker engine. Won't be doing either obr or esp engine any favors with that gear set. That's their point. High reving an engine without decent load isn't good for it, why there are unloaded and loaded rpm specs.
 
Seandonato73 said:
It's going to pull about the same rpm, just get there faster. You're already under geared hitting 19k with the weaker engine. Won't be doing either obr or esp engine any favors with that gear set. That's their point. High reving an engine without decent load isn't good for it, why there are unloaded and loaded rpm specs.
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Hi, thanks for your useful response.

For my general use of the Baja 5B, say around a paddock, the 17/57 gearing is great. It doesn't feel under geared at all. But then it isn't hitting anything like 19k rpms then, either.

But at the 1/4 mile strip, I'm doing 0-40 mph runs.

When I get an engine that's capable of hitting 60mph, I'll use the lowest gearing I can to get to that speed and shoot for good 0-60mph times.

I may not be doing a full mod OBR G340 Reed V2 any favours running 17/57, but it's courteous to answer questions adequately prior to making a £460 sale. Not just tell your customers what to do. 👍

My question was - what sort of RPMs would this engine achieve on that gearing. My question wasn't 'what gearing do you recommend'. I'll arrive at that myself once I know the damn specs - and RPMs is one of them. They're quite happy to tout 9.4hp, but then get all cloak and dagger about RPMs. 🤣

Your answer was helpful - it quantified 'about the same' but 'get there quicker'.

This is an answer that should have been afforded - at the very least - by OBR UK, but I was told 'keep what you have'. 💩

This is the thing - if I'm shooting for 0-40 times, getting there quicker Vs not getting there at all is actually a gain on 17/57, is it not?😝

And whilst I'm far from destructive with my rigs, I'm not trying to 'do them any favors' either. It's good to rev the tits off them doing 0-40 times.

There shouldn't be any presumptions, or 'use them like we do or don't bother getting them at all' kinda attitude. If I can get a Fuelie 26 to 49mph and 0-40 in 2.78 seconds, imagine what I might get my rig to do with an OBR G340 Reed V2. Or a Taylor. Or ESP.

People on this Forum had alluded to 'good service' from OBR, but I've yet to see any from OBR UK. It's not a great start, I'm not going to lie.
In the interests of transparency, OBR USA came back with this answer, which is very helpful.

1000023686.png

I hear that 17/57 is very low, and it is pretty clear that this would not be the gearing to use down the 1/4 mile strip.

But the difference is that I was given a specific answer. 👍 Much, much better.

I suppose it's very easy not to be arsed securing a sale when it's not your business on the line. 😝

Thank you OBR USA from Wales. 👍
 
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max rpm is just one thing and doesn't tell the story of an engine or the power it produces. I've always felt obr over sells their hp numbers, however having owned quite a few ported zen engines over the years stepping up from a 26cc to a 32/34 is night and day power difference. In a light weight baja you'll be over reving the engine with that short gearset and not taking advantage of the torque they produce. Most every larger zen, even stock engines will hit 18k rpm loaded, ported can hit 19-20k. Light loads and low gears stresses the connecting rod, for really no reason. You're not gaining anything, and risk damage to the engine. Invest in a good 2 speed transmission if you're interested in speed runs, you'll keep the engine in a good rpm/power range and be able to take advantage of the larger engines torque. Obr eu may not have answered the question you asked, which they should have, but they should have explained why your question is flawed and why they (and everyone else) is reccomending higher gears with either of those engines.
 
Seandonato73 said:
max rpm is just one thing and doesn't tell the story of an engine or the power it produces. I've always felt obr over sells their hp numbers, however having owned quite a few ported zen engines over the years stepping up from a 26cc to a 32/34 is night and day power difference. In a light weight baja you'll be over reving the engine with that short gearset and not taking advantage of the torque they produce. Most every larger zen, even stock engines will hit 18k rpm loaded, ported can hit 19-20k. Light loads and low gears stresses the connecting rod, for really no reason. You're not gaining anything, and risk damage to the engine. Invest in a good 2 speed transmission if you're interested in speed runs, you'll keep the engine in a good rpm/power range and be able to take advantage of the larger engines torque. Obr eu may not have answered the question you asked, which they should have, but they should have explained why your question is flawed and why they (and everyone else) is reccomending higher gears with either of those engines.
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Thanks for your comprehensive answer.

Helpfully, you reiterate what OBR USA stated in the email shown above.

For the avoidance of doubt, I fully understand the concept of gearing and to be clear - it wasn't the question I asked!

OBR USA also gave the advisory that 17/57 is a low gear ratio for an engine that produces more torque - but they (specifically Dan Silagy) answered my question and gave me some further options. An opportunity that had not been scoped by OBR UK.

I'm interested in 0-40, 0-50 and 0-60 times, so needed to know typical loaded RPMs - including what was attainable on the lowest gearing.

There was no opportunity to go into such details with OBR UK, because I was shut down. 💩

With my current setup - I know exactly what RPMs I'm getting in my rig, my rollout of 68.21mm/rev on 165mm tyres, my top speed and my 0-40mph times.

Yes, I could easily gear up my existing engine, but my 0-40 times would suffer as a result.

I want to know the characteristics of a potential new Reed Case engine for my lightened Baja 5B for the purposes of making it even more rapid than it is now.

As for 2 speeds - I like the idea of it, but it would need to be compatible with my TR clutch system thus I'm happy to see what can be achieved with fixed gearing for the foreseeable. 👍 Also, it gives a like for like comparison between the old faithful -15 year old - Fuelie 26S and whatever new modified engine I bolt in.

If anybody has some TR clutch compatible 2 or 3 speed suggestions, please let me know.

As for my Baja 5B speed runs, I'll be wanting to explore the 2 stroke's upper RPMs - even on higher gearing. Whether that's at 49mph on 17/57, or 62mph on 21/53 and 89.67mm/rev - please understand that my expectations are not based on myth or an inability to grasp how gearing works. For 0-50mph runs, I might choose gearing somewhere in between - like 19/55, which on a rollout of 78.55mm/rev, would give me a top speed of 54mph @ 18500rpms.

Essentially, I would still need to know how willing the engine is to rev - pulling that recommended gearing - to know if it's going to hit 60mph +. That's my aim.

And thankfully, OBR USA answered my question rather than just dismiss out of hand like the Irish branch did. Note: they also highlighted the upsell to the signature engine, which can be modded specifically for higher RPMs, which for a speed run rig might be preferable. This aspect seemed entirely lost on OBR UK, which is surprising for obvious reasons.

Screenshot_20240813-104642.png

Now I know what my options are with OBR, I can make an informed choice. 👍

Edit to add: for the purposes of obtaining the very best 0-40mph times, it's an essential thing to know what the peak RPMs are for 17/57. 😜 21/53 would be fit for 0-60mph, but would it beat 17/57 to 40mph? I'm not convinced it would. And before I'd assert that it's a flawed question to ask, I'd want to find out first. 👍

Further edit regarding "OBR EU".

Whilst OBR UK is clearly in East Ireland (which is not part of the UK), it's website clearly states OBR UK. There is no OBR EU. Interesting. 🤔
 
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horatio said:
Further edit regarding "OBR EU".

Whilst OBR UK is clearly in East Ireland (which is not part of the UK), it's website clearly states OBR UK. There is no OBR EU. Interesting. 🤔
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just as some info, OBR UK is a one man band and a secondary job for paul hedges (sonic),
there used to be a guy called keiran working for sonic as well, but not sure if thats still the case,
sonic is from the south of england but lived in ireland for a long time now,
he's run OBR UK for sean o'nneil for quite a while now as an easier way to get OBR engines over to our side of the pond for easier distribution around the UK and europe, i say for sean o'nneil but i think OBR UK is its own company when all said and done and more a distributer,
sonic is very knowledgable on the whole OBR range and he will always advise on the best gearing for the longevity of the OBR engines as a first point,
i'm pretty sure he may have misunderstood what you were asking, or had a crap ton of emails to answer and missed the point you were asking,
sean and dan run OBR USA as there first job and its there day to day living and they have a much deeper understanding of there products,
sonic will always be as helpful as he can be but bare in mind its his second job,
i'm not trying to start any argument or anything like that, just trying to put things in perspective about OBR UK (y)(y):)
 
spents said:
just as some info, OBR UK is a one man band and a secondary job for paul hedges (sonic),
there used to be a guy called keiran working for sonic as well, but not sure if thats still the case,
sonic is from the south of england but lived in ireland for a long time now,
he's run OBR UK for sean o'nneil for quite a while now as an easier way to get OBR engines over to our side of the pond for easier distribution around the UK and europe, i say for sean o'nneil but i think OBR UK is its own company when all said and done and more a distributer,
sonic is very knowledgable on the whole OBR range and he will always advise on the best gearing for the longevity of the OBR engines as a first point,
i'm pretty sure he may have misunderstood what you were asking, or had a crap ton of emails to answer and missed the point you were asking,
sean and dan run OBR USA as there first job and its there day to day living and they have a much deeper understanding of there products,
sonic will always be as helpful as he can be but bare in mind its his second job,
i'm not trying to start any argument or anything like that, just trying to put things in perspective about OBR UK (y)(y):)
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Thanks for that!

Look, we all have off days where our tolerance levels reach zero. The dude at OBR UK probably gets a million emails a day from people asking 'how fast is it?'.

When he read my email, his brain likely filtered it as 'I want your best engine for running around on 17/57 because that's the only ratio I want to run'. Possibly.

And to be clear, I don't want an argument either. I want a reed engine. Possibly one with lashings of TR billet, to go with my other stuff.

I had tried to organise a phone call with the bloke, but clearly that didn't happen. 🤣

I tend to have a zero tolerance to bad attitudes, so maybe we should try again.

The reality is that OBR Zenoah based engines seem like an ideal choice for me and what I'm trying to do, despite what he thought I may have meant.

Dan Silagy is still enquiring if there's a way for them to supply an engine for me at roughly the same price as OBR UK - but the shipping is going to be difficult to mitigate. 👍
 
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