[VHEZO]

"Flame proof noob zone....love it!!

Highly applicable here though, I dont know anything about Suzuki motors, although I wish i did.

I need some advice from you fellas who know about the G13 / G15 / G16 engines... There is a mob in the USA using these motors for aircraft.
Using the G13BB, they are getting 112hp @5800 & 126hp @6500. The only details I know if that the internals are stock, its NA, SOHC EFI.
Is this an unrealistic HP rating for the G13BB? Whats the max HP you can get from the G13 while still keeping it reliable? Remember, these HP numbers are crank HP.

They are also doing something with the G15, which i dont think we have available in Australia? They are getting 131hp@5800 & 147hp@6500rpm.
Both of these engines weigh under 80kg. They dont use the G16, apparently its too heavy.

I suppose my questions are.... is the G15 available here? Is there any way to get min 130hp (flywheel) reliably from the G13? Is it possible to get over 150hp reliably from the G16?
If you were building a lightweight motor with the best HP output (continuous high rpm), how would you go about it?

I know its not based on cars, but i really do appreciate all your input!

[Gwagensteve]

Are these ratings on Avgas? Something higher like race fuel at 109 octane +?

Any other information on tuning?

They're VERY high. Maybe they are US horsepower?

This isn't really a board where people will gave data on maximum reliable horsepower, we're happy our cars run and don't have cracks in the head. (will mine probably does, but anyway)

With enough octane and enough ignition timing wound in, maybe? but I just can't imagine getting almost 100hp/l out of a G13BB, especially in an aviation setting where torque is really what you're after and it's for long periods at high load.

No, we never got the G15.

If I wanted a light engine engine for continuous high RPM it would be a motorbike engine, not an engine designed for a cheap economy car.

[VHEZO]

No, these ratings are on 95 octane mogas. The ratings I gave are at full throttle, but they tend to run them at 65% power in cruise. I dunno how they are doing it, but I can say they are getting those numbers AND reliability.... the test engine has over 4000hrs on it. After covering with the Chinese manufacturers, they are claiming 120hp rating for the G13BB. I'm almost thinking of buying one out of the states and disassembling it to see what's there. But that's an expensive excersis with the exchange rate and freight. Maybe just one of life's mysteries?

[Boggomobile]

Gwagensteve wrote:

They're VERY high. Maybe they are US horsepower?

Chinese Manufacturers, maybe they are Chinese horsepower?

[Gwagensteve]

I just can't see how it's possible.

If that power was at 7500rpm, I'd have no problem, but I don't understand how they're (evidently) getting a large torque increase at relatively low RPM. and then going on to make a significant increase in horsepower at the same RPM as stock.

to get 126hp at 6500 rpm, the engine has to make ~100ft/lb of torque. (Stock is 77-85ft/lb).

With no other tools to do that (stroke, capacity etc) it has to be ignition timing. It can't be cam profile or porting because that would move the power band up - what they're reporting is basically a stock power band but with 50hp more at eh sae RPM. To do that must require masses of ignition timing and conventional wisdom would say lots of octane to prolong the burn to generate that torque.

Do you have a link?

[Gwagensteve]

I found this, and these numbers are completely credible

https://www.experimentalaircraft.info/h ... ngines.php

100hp for a very custom G13BB at 5800rpm running high end injection, that's completely believable and still substantially above the factory power. That looks like a nice, safe engine for a small plane (well, it's still a G series, so until the head cracks or the piston skirts fall off) *laughs in G13B*

[VHEZO]

You've found the mob I was referring to and their "AM13" G13BB

But dig a bit further.... here is the link. You'll see that the power ratings I'm talking about down the bottom of the page with the rest of rhe engine specs
https://aeromomentum.com/am13.htm

[VHEZO]

https://aeromomentum.com/am13.html

Sorry, missed a letter in the link..

[Gwagensteve]

I'm a bit confused and that link hasn't made it much clearer.

OK, so this is an American vendor buying in Chinese made G series clones(?) and modifying them for aviation use, I assume.

Stock G13BB has 9.5:1 compression ratio. These are advertised as 10.1.

Knowing the've upped compression ratio, have added knock sensor and are tuned for 95 octane, I'd say the 100hp at 5800rpm is perfectly achievable. But is 95 octane an "auto fuel" in the US? Isn't 93MON the highest pump fuel? Is that 95 octane MON or RON? (If it's MON it's equivalent to easily 100 Octane RON and at 10.1 compression and with lots of timing wound in, I'm sure 100hp is easy, 112? hmm. 126? no. We get 98RON here and I've wound timing in on a turbo EFI motor, the best candidate I can't think of for more octane, and 91RON to 98 lifted torque, but it wasn't adding a heap of horsepower.


Now to the hot versions. $4K for 12hp is a lot of coin, and they're very non-specific about it - none of the technical specs are different. still 10.1 compression, same capacity. Do these 112hp engines exist? the web site feels very mid 2000's. Are these engines getting around? has anyone put one of the dyno? Are they really getting 126hp with the same compression ratio and the same economy?

They're claiming very, very impressive BSFC, better than something like a Prius that uses it's hybrid system and the CVT to hold the engine at peak BSFC figures. The G series head flows well but there's no variable cam timing to lean on, they're not very efficient motors by modern standards. They don't run stratified injection etc - if they run lean they'll detonate readily. I get the knock sensor will pull timing out at that point, but there goes your torque and BSFC, so if it's cranked right up near detonation all the time small changes in atmospheric conditions or fuel quality (because we're using pump fuel here, right, not avgas, nowhere near the QC) and you're all over the knock sensor and back at 75hp.

I don't know, it all looks a bit fanciful to me. Maybe someone saw 126HP on a dyno at 6500rpm at some point. Maybe they saw 0.39lb/hp/hr at some load point on the dyno with some variation of the motor. a 2000 hour life before a rebuild would equate to 70-80,000km in a road car which is fairly low by car standards, so that's a fairly stressed engine, but how many of these experiemental/ultralight aircraft will ever fly for 2000hrs to prove them wrong? Who is going to dyno one to prove it's doing 126hp? has anyone pulled one down at 2000hrs? 90hp/l is heading towards race car territory for that motor and it's going to wear quick.

We're outside of normal FAA approval here, aren't we, as these are all considered "experimental" - is that how it works? so ratings etc are all a bit arbitrary (?)

sorry, lots of questions, but well over 90hp/litre at 6500rpm and 0,39lb/hp/l on an early 90's economy engine design, 95 octane or not, just doesn't ring true.

[VHEZO]

I can completely understand what your saying. Yes they are getting these from China. The Chinese rate their version of the engine at 120hp neat. I'm not sure on the fuel, but I know it's not 100LL avgas.
These aren't approved at all, so they fit into the experimental category. This company is still going strong, you can see them all over YouTube with this motor, and all the other suzuki derivatives. They are adding a 2.0 turbo which looks identical to the G4NC Hyundai motor, and the power specs are realistic in comparison to oem claims.
These are also being used in airboats, which have had these motors for years, and they've got some pretty high hours on them. The other thing I find astonishing is the tiny quad core radiator that can handle the cooling, that thing is small. These guys are alive and well and in their peak. To me, I'd love to get my hands on one of these just to see what's in it (am13) but if I were buying I'd want the am15 based off the g15 for my circumstances. This guy is very tight lipped about how they do it, and so would I if I were him. They have one major competitor which is viking engines and they use the Honda L15a series for similar HP, but at a greater weight penalty. The 1.0 and 1.6 ecoboost have my attention also.
I dunno, I just hate not being able to work out how people do things, or how they achieve these numbers. I'm sure you can relate
They have their own dyno there, and not only that, alot of their customers are experimental kit suppliers who have verified the figures... they wouldn't last long if the numbers claimed were fudged in any way. The two key numbers for any aircraft engine is HP and weight......fuel flow comes in a relaxed third place.

Here is a bit more interesting reading from these guys, maybe you can find some further clues here. Mate, your knowledge here is insane
https://aeromomentum.com/reason.html

[VHEZO]

Gwagensteve wrote:

I'm a bit confused and that link hasn't made it much clearer.

OK, so this is an American vendor buying in Chinese made G series clones(?) and modifying them for aviation use, I assume.

Stock G13BB has 9.5:1 compression ratio. These are advertised as 10.1.

Knowing the've upped compression ratio, have added knock sensor and are tuned for 95 octane, I'd say the 100hp at 5800rpm is perfectly achievable. But is 95 octane an "auto fuel" in the US? Isn't 93MON the highest pump fuel? Is that 95 octane MON or RON? (If it's MON it's equivalent to easily 100 Octane RON and at 10.1 compression and with lots of timing wound in, I'm sure 100hp is easy, 112? hmm. 126? no. We get 98RON here and I've wound timing in on a turbo EFI motor, the best candidate I can't think of for more octane, and 91RON to 98 lifted torque, but it wasn't adding a heap of horsepower.


Now to the hot versions. $4K for 12hp is a lot of coin, and they're very non-specific about it - none of the technical specs are different. still 10.1 compression, same capacity. Do these 112hp engines exist? the web site feels very mid 2000's. Are these engines getting around? has anyone put one of the dyno? Are they really getting 126hp with the same compression ratio and the same economy?

They're claiming very, very impressive BSFC, better than something like a Prius that uses it's hybrid system and the CVT to hold the engine at peak BSFC figures. The G series head flows well but there's no variable cam timing to lean on, they're not very efficient motors by modern standards. They don't run stratified injection etc - if they run lean they'll detonate readily. I get the knock sensor will pull timing out at that point, but there goes your torque and BSFC, so if it's cranked right up near detonation all the time small changes in atmospheric conditions or fuel quality (because we're using pump fuel here, right, not avgas, nowhere near the QC) and you're all over the knock sensor and back at 75hp.

I don't know, it all looks a bit fanciful to me. Maybe someone saw 126HP on a dyno at 6500rpm at some point. Maybe they saw 0.39lb/hp/hr at some load point on the dyno with some variation of the motor. a 2000 hour life before a rebuild would equate to 70-80,000km in a road car which is fairly low by car standards, so that's a fairly stressed engine, but how many of these experiemental/ultralight aircraft will ever fly for 2000hrs to prove them wrong? Who is going to dyno one to prove it's doing 126hp? has anyone pulled one down at 2000hrs? 90hp/l is heading towards race car territory for that motor and it's going to wear quick.

We're outside of normal FAA approval here, aren't we, as these are all considered "experimental" - is that how it works? so ratings etc are all a bit arbitrary (?)

sorry, lots of questions, but well over 90hp/litre at 6500rpm and 0,39lb/hp/l on an early 90's economy engine design, 95 octane or not, just doesn't ring true.

Gwagensteve... mate is it alright if I send you a PM?

Sent from my SM-G973F using Tapatalk

[Gwagensteve]

Oh, sorry I missed this - sure.