GS1100 Dyno Results Analysis

[posplayr]

There have been a few threads lately discussing Dyno Results and in particular a comparison of shaft v.s. drive 1100's.

http://www.thegsresources.com/_forum/showthread.php?t=169363

http://www.thegsresources.com/_forum/showthread.php?t=169387

The point of this thread is to lay bare some of the various numbers that get thrown around and what they mean and how Chain and Shaft drive hp numbers for 1100's compare. Extension to other bikes is prudent based on a reasonable assessment of similarity, but over extension to comparison that is far from those similarity is suspect.

This is NOT a theoretical discussion, although it is based on the a first principle of physics, "conservation of energy" and a principle analytic method in mechanical engineering for power conversion "efficiency" determination.

The principle analysis approach used here is to take available measured data (rear wheel dyno) and specif iced manufacturer (Suzuki) data (at the transmission output) to develop an empirical approximation that matches the above. In order to compare Chain Drive v.s. Shaft Drive systems, we have to do further decompose losses into those that are common to both system and those that are dissimilar. We use additional engineering data from an independent source for that purpose.

Note: This is not the usual detail that engineers use to perform analysis as in many cases the steps that I indicated are accepted without justification as they are so obvious. However, that is not to say that the methodology is invalid. It is just a bit over cooked for the simplicity of this problem. That being said, I found it necessary to demonstrate each step as when I did this in the previous post, the many details I took for granted made it appear as if I was just guessing. To a certain extent I was but, it should be clear that it is an educated guess and based on years of successful experience and analysis in engineering, doing the same thing on similar and as well as much more difficult problems.

The conclusions are:

1. Common Losses for Chain and Shaft beyond the transmission are 7.5%
2. Secondary Drive losses are 7.5% and 15-16% for chain and shaft drive respectively.
3. Chain Drive Total RW %loss => 15% of Suzuki Rated
4. Shaft Drive Total RW %loss => 23% of Suzuki Rated

If anybody has any comments or further information on stock GS1100 Dyno results please post and I will incorporate that information as appropriate.



The Analysis which deduced the above conclusion follows:

IIRC, I have read that Suzuki measures the transmission output shaft for rated power on Chain drives (it was from an article on GS1100E's). This therefore includes the transmission loss. So rated is not at the crank but includes a loaded transmission. I would ASSUME that the Suzuki also measure the Shaft drive engines in a similar or equivalent way. Assuming the above being the case, we can compute percentage power loss according to standard engineering practice between chain drive and shaft drive. This should estimate the total DRIVE losses from transmission output to the tractive effort as the rear tire. The following Equation is easy to derive:

% DRIVE LOSSES = 100% x ( 1 - Dyno_rwhp / Rated_hp )

As it follows directly from the definition of transmission efficiency.

The transmission efficiency is the ratio between the input and the output power.​

t= Wout/Win= Tout / Tin​

To provide an overview , refer to the following figure to see what this analysis is about:​

The DRIVE losses for Chain and shaft obviously differ (chain v.s. multiple gear reductions). However some of the DRIVE losses between Chain and Shaft are the same (specifically R tire , R wheel windage and R wheel bearing losses).​

Daniel, (7981GS) quoted us drive line losses which between shaft and chain; I assume he has a valid reference.
http://www.thegsresources.com/_forum/showpost.php?p=1329178&postcount=5​

Typical drive line loss is 15% with a driveshaft.

Typical loss with chain and sprockets is 5-10%.​

Daniel​

We now have the basis to decompose the total DRIVE loss percentage into those that are common and those that are not.​

Here we have a series of calculations using the formula:​

Total RW % Loss = 1-Dyno/Rated = SECONDARY DRIVE Losses + COMMON LOSSES​

I have included some information from Cycle April 1982 review of the GS110EZ

Here is a summary of how this equation and spreadsheet model are used to perform the analysis​

A question came up about the validity of the %loss relationship being related to power conversion. Here is a reference that provides some basic formulas for calcualtion of gearing efficency

http://www.roymech.co.uk/Useful_Tables/Drive/Gear_Efficiency.html

I dont have a reference for chains but this appears to be one; anybody else have one?

http://www.ingentaconnect.com/content/tandf/cjen/2004/00000015/00000006/art00004

​

 

[rapidray]

Actually Jim, the difference from an engine dyno to a rear wheel dyno on a GS 1100 or 1150 is about 18 %. Just so you know. Ray.

 

[Nessism]

Hey Jim,

In that other thread I did mention those numbers referenced to me but I did not come up them, I was simply repeating what had already been mentioned in that same thread.

I have some Cycle World magazine dyno info at home that I'll dig up for this discussion that factually references GS1100E rear wheel horsepower, but I'm pretty sure the actual number was just over 90 hp, not 94 hp. Another thing to keep in mind is we don't know how Suzuki comes up with their numbers. For example, maybe they disconnect the stator. We don't know. At any rate, this discussion strikes me as too much speculation, and not enough facts. We know that the shaft drive systems consumes power, mostly from the 90 degree power turns, but we don't know how much. Nor to we know what the real hp numbers are for the engine, only what Suzuki's ad copy states.

 

[posplayr]

Hey Jim,

In that other thread I did mention those numbers referenced to me but I did not come up them, I was simply repeating what had already been mentioned in that same thread.

I have some Cycle World magazine dyno info at home that I'll dig up for this discussion that factually references GS1100E rear wheel horsepower, but I'm pretty sure the actual number was just over 90 hp, not 94 hp. Another thing to keep in mind is we don't know how Suzuki comes up with their numbers. For example, maybe they disconnect the stator. We don't know. At any rate, this discussion strikes me as too much speculation, and not enough facts. We know that the shaft drive systems consumes power, mostly from the 90 degree power turns, but we don't know how much. Nor to we know what the real hp numbers are for the engine, only what Suzuki's ad copy states.

Ed,
The assumptions are as was stated. The stator is worth less than 1 hp but regardless it is doubtful they would remove it. And if they would what is to prevent us from thinking they would not further manipulate the spec power? We could also speculate that they did not use calibrated equipment. That would be easy enough to do.

The pragmatic reality is that we can reasonably assume that the spec performance is as stated by Suzuki as it is not that hard to independently verify and the damage associated with providing false information could be very detrimental to corporate image. All that is required to confirm the information is to put a torsion dyno off the transmission output shaft.

Further, everybody including Suzuki know that the rated hp of the GS1100E was not by any means an upper limit on performance. The motor could be easily extended in hp by a whole array of performance upgrades. So why lie?

The essential point I'm making is that there is no obvious reason for Suzuki to falsify the spec numbers and much to lose for doing so. The assumption that Suzuki spec is accurate within engineering and manufacturing tolerance is a reasonable assumption. Assuming otherwise is NOT.


In comparing Dyno numbers we need to remember to account for the difference in rated power between the 80-82 16V 1100E of 108 hp and the 83 16V 1100E of 111 hp.

At 15% (consensus) power loss we get 91.8 and 94.3 rwhp for the 108 and 111 hp versions respectively.

 

[Nessism]

In comparing Dyno numbers we need to remember to account for the difference in rated power between the 80-82 16V 1100E of 108 hp and the 83 16V 1100E of 111 hp.

At 15% (consensus) power loss we get 91.8 and 94.3 rwhp for the 108 and 111 hp versions respectively.

Jim,

I accept the 15% estimate, which has been confirmed by Ray.

 

[Guest]

You must have a lot of time on your hands, Jim.

 

[Graham]

Something seems off.

 

[headsbikesmopars]

IIRC the '80 and '81 GS1100 was rated by Suzuki at 105 hp. Even though the '81 was considerably faster in the road tests. Mainly due to the revised seat angles Suzuki used on the heads on the '81 models. JFYI.

Terry

 

[posplayr]

Actually Jim, the difference from an engine dyno to a rear wheel dyno on a GS 1100 or 1150 is about 18 %. Just so you know. Ray.

Ray the Cycle April 82 Dyno numbers for GS1100EZ are coming in right at %LOSS 14.3%

I also did a complete table of Dyno power v.s %loss to show how teh dyno numbers woudl be distrinuted for vatiaions in Spec Hp and measured Dyno power.

 

[posplayr]

IIRC the '80 and '81 GS1100 was rated by Suzuki at 105 hp. Even though the '81 was considerably faster in the road tests. Mainly due to the revised seat angles Suzuki used on the heads on the '81 models. JFYI.

Terry

Terry,
Here is a Cycle article from April 1982 describing the sensitivity to seat angles which is why I have been so interested in the head work and am glad you did mine. I also updated teh results from both my head as compared to Nicks in the other thread.

http://www.thegsresources.com/_forum/showthread.php?t=137631

Merry Christmas and thanks again.
Jim

 

[posplayr]

IIRC the '80 and '81 GS1100 was rated by Suzuki at 105 hp. Even though the '81 was considerably faster in the road tests. Mainly due to the revised seat angles Suzuki used on the heads on the '81 models. JFYI.

Terry

Terry,
I thought 80-82 were all rated the same at 108hp, but there was alot of bike to bike variation in the earlier years due to the manuafacturing tolerances on the valve seat angles. Once Suzuki improved on teh manufacturing tolerances along with some increased cam lift (in 83) the power went up to 111 hp.

Jim

 

[posplayr]

Something seems off.

Merry Christmas Graham

 

[posplayr]

You must have a lot of time on your hands, Jim.

Well it has been bitter cold and rainy here. I don't think we have been in theh 70's for almost week.

 

[headsbikesmopars]

Jim ,
nice work on the graphs. WELL DONE ! From memory, I believe Suzuki rated the '80-'82 GS1100 at 105 and the '83 GS1100 at 108 while the Katana's were 111. IIRC. But that was a long time ago..Jim see what you can dig up on this . Thanks. Related topic, ..'84 1150 rated @ 119 and '85 1150 @ 124. Again..IIRC. Also the '84 @119 and rear wheel was 101 so that falls right in line with your graph .

 

[posplayr]

Jim ,
nice work on the graphs. WELL DONE ! From memory, I believe Suzuki rated the '80-'82 GS1100 at 105 and the '83 GS1100 at 108 while the Katana's were 111. IIRC. But that was a long time ago..Jim see what you can dig up on this . Thanks. Related topic, ..'84 1150 rated @ 119 and '85 1150 @ 124. Again..IIRC. Also the '84 @119 and rear wheel was 101 so that falls right in line with your graph .

Terry,
I have been looking through some old motorcycle magazines and I did find a quote as you mentioned 105hp on the 80-82 bikes and a step up to 108hp for the 83 ED. That is strange as I had always thought 108 and 111. (see attachment Cycle World June 83)

Well the numbers do jump around a bit and there is likely some confusion as to what an 83 E actually was. Also the 18% number Ray refered to seems to be from an April 1983 Cycle 1100 comparision where the ESD only registed 90.9 hp on the Dyno. But if we assume 108 rather than 111 hp then that computes to a loss of 15.8% and not 18%.

Unless someone has back to back rear wheel and output shaft torque numbers, I'm still pretty much conviced that 15% LOSS is a good average number.
Jim

 

[davel]

fwiw,

Here are dyno results of a GS1100ES from Cycle Mag April 1983

 

[davel]

Here are dyno results from my stock 82 GS1100EZ with 40,000mile. It was tested at sea level on 01-06-2010

http://www.thegsresources.com/_forum/showthread.php?t=156060

This chart lists torque and RPM for both tests.

Note the maximum difference between these two test (taken on different dynos 27 years and 40,000 miles apart) is 1 lb-ft...Both engines peak at 62lbft and 91hp.

It surprised me too. Uncanny.

 

[posplayr]

fwiw,

Here are dyno results of a GS1100ES from Cycle Mag April 1983

That test was for an 83 GS1100ESD which according to the article I posted from Cycle World was 108 hp, while yours EZ was supposedly 105 hp. So we would expect a higher output than the 91 rwhp closer to 94 hp.

There is a Cycle World April 82 article which claimed a 108 hp for the EZ and recorded 92.6 hp. If we assume the spec was actually 105 and not 108 then we have a 3 hp spec deficient EZ posting 1.5 hp better than the ESD. So we have to be careful of hanging our hat on only 1 or 2 measurements.

It seems we are dealing with +/- 1 or 2 hp variation due to the bike to bikes variation and +/- 1 or 2 hp due to Dyno accuracy so it is hard to make a judgment based on one set of data even though you would appear to have the same results.

 

[Guest]

That test was for an 83 GS1100ESD which according to the article I posted from Cycle World was 108 hp, while yours EZ was supposedly 105 hp. So we would expect a higher output than the 91 rwhp closer to 94 hp.

There is a Cycle World April 82 article which claimed a 108 hp for the EZ and recorded 92.6 hp. If we assume the spec was actually 105 and not 108 then we have a 3 hp spec deficient EZ posting 1.5 hp better than the ESD. So we have to be careful of hanging our hat on only 1 or 2 measurements.

It seems we are dealing with +/- 1 or 2 hp variation due to the bike to bikes variation and +/- 1 or 2 hp due to Dyno accuracy so it is hard to make a judgment based on one set of data even though you would appear to have the same results.

IMHO, the hp difference between both years is really splitting hairs & a moot issue on the street...having ridden both bikes in various states of tune, I can honestly say there isn't any discernible 'seat of the pants' difference from one year to another, definitely no noticeable difference in performance like when stepping up to an 1150 with it's significant difference in hp. 3 hp is well within the normal variation parameters for 2 stock bikes of the same year, or even the same bike on two different days, or two different dynos. The difference on paper is small enough that rider size & weight are going to be a bigger factor in the real world. The most significant improvement was the welded crank for '83, which instantly makes it a better choice, esp. if performance mods are planned.

 

[posplayr]

IMHO, the hp difference between both years is really splitting hairs & a moot issue on the street...having ridden both bikes in various states of tune, I can honestly say there isn't any discernible 'seat of the pants' difference from one year to another, definitely no noticeable difference in performance like when stepping up to an 1150 with it's significant difference in hp. 3 hp is well within the normal variation parameters for 2 stock bikes of the same year, or even the same bike on two different days, or two different dynos. The difference on paper is small enough that rider size & weight are going to be a bigger factor in the real world. The most significant improvement was the welded crank for '83, which instantly makes it a better choice, esp. if performance mods are planned.

Well this really is not about how fast either bike is, but what loss factor to apply in developing a Dyno estimate. For some of the same reasons you mention it will vary bike to bike, dyno to dyno.