Dyno Results Needed - stock vs. pods/pipe/jet kit

[Guest]

I need independent dyno results of the output of an engine with stock airbox, jetting and exhaust vs. the same engine with pods, a pipe and a properly tuned jet kit.
Any format, an excel spreadsheet, comma delimited file, or the normal dyno output chart will suffice.
Cycle World published an article on a GS1100E showing that using only Mikuni jet changes on a stock vs. modified engine shows no improvement in performance, hence the mods are useless. I would like to refute the article by showing a properly jetted carb (i.e. DynoJet kit) will show a performance increase. If it does not, so be it, but my stance is that a DynoJet kit or equivalent is required when pods/pipe are installed on CV carbs.
Thanks in advance.

[trevor]

I need independent dyno results of the output of an engine with stock airbox, jetting and exhaust vs. the same engine with pods, a pipe and a properly tuned jet kit.
Any format, an excel spreadsheet, comma delimited file, or the normal dyno output chart will suffice.
Cycle World published an article on a GS1100E showing that using only Mikuni jet changes on a stock vs. modified engine shows no improvement in performance, hence the mods are useless. I would like to refute the article by showing a properly jetted carb (i.e. DynoJet kit) will show a performance increase. If it does not, so be it, but my stance is that a DynoJet kit or equivalent is required when pods/pipe are installed on CV carbs.
Thanks in advance.

I have dyno results for my 83 1100e done a couple of months ago. With V&H 4-1 and stock airbox with K&N filter. I posted it here somewhere but now don't know where. If you have not found it by tonight I will post it again.

[koolaid_kid]

I have dyno results for my 83 1100e done a couple of months ago. With V&H 4-1 and stock airbox with K&N filter. I posted it here somewhere but now don't know where. If you have not found it by tonight I will post it again.

Please do so. A couple of questiions: was there an improvement, and did you start the thread yourself?

[trevor]

Please do so. A couple of questiions: was there an improvement, and did you start the thread yourself?

No I don't think I started it myself. And as far as improvement I don't know as I never had it tested before the 4-1. I was looking for help in jetting. So I had the dyno done. I'm pretty sure I posted a pic of the graph, I will keep looking too.

[posplayr]

I need independent dyno results of the output of an engine with stock airbox, jetting and exhaust vs. the same engine with pods, a pipe and a properly tuned jet kit.
Any format, an excel spreadsheet, comma delimited file, or the normal dyno output chart will suffice.
Cycle World published an article on a GS1100E showing that using only Mikuni jet changes on a stock vs. modified engine shows no improvement in performance, hence the mods are useless. I would like to refute the article by showing a properly jetted carb (i.e. DynoJet kit) will show a performance increase. If it does not, so be it, but my stance is that a DynoJet kit or equivalent is required when pods/pipe are installed on CV carbs.
Thanks in advance.

This is a related discussion on Dyno results. Unfortunately many of my figures are missing. Nessim (Ed) has posted an older reports on various 4:1 performance comparisons and the results were mixed at best. It takes more than just a pipe to get performance. usually pods and jetting.

http://www.thegsresources.com/_forum/showthread.php?t=169468&highlight=dyno

[koolaid_kid]

This is a related discussion on Dyno results. Unfortunately many of my figures are missing. Nessim (Ed) has posted an older reports on various 4:1 performance comparisons and the results were mixed at best. It takes more than just a pipe to get performance. usually pods and jetting.

http://www.thegsresources.com/_forum...highlight=dyno

Thanks, Jim. I saw that thread. And I agree, just a pipe is only going to increase noise polution.
We agree that it takes all three. Cycle World did the test with pods/pipe and mikuni jets. No DynoJet kit. They showed no improvement and concluded that the money was wasted. I maintain the DynoJet kit is crucial to complete the circle, but I need empirical data to back up my position.

[posplayr]

Thanks, Jim. I saw that thread. And I agree, just a pipe is only going to increase noise polution.
We agree that it takes all three. Cycle World did the test with pods/pipe and mikuni jets. No DynoJet kit. They showed no improvement and concluded that the money was wasted. I maintain the DynoJet kit is crucial to complete the circle, but I need empirical data to back up my position.

here is one of Ed's threads on pipes.

http://www.thegsresources.com/_forum/showthread.php?t=150190&highlight=pipe

You need empirical data that rejetting is required for a pipe change? All you need is a back to back compare of swapping out a 4:2 with a 4:1 and use a WBO2 sensor to record the AFR changes.

Why convolute the analysis with hp and dynos uncertainties?

EDIT: OK I see you want to prove Hp gains and that you need a DJ kit to do it. Well the main difference between changing mains and the DJ kit is the needle and that will only affect the mid range and not peak hp so not sure where you are going to go with this.

What the article was probably showing is that on a stock bike, there are no real hp gains by using a pipe alone. But that doesn't explain the loss in weight from that 4:2 nor does it add in the effect of pods, nor an other engine modifications.

I would think doing the back to back tests using after tuning with a WBO@ but adding in the back to back dyno runs as well will give you the raw data to develop some conclusions.

[John Kat]

I tested my two GS 1000 S almost back to back and the results were...surprising
First a 100% OEM GS 1000 ST in European spec ( VM 30 carbs and the specific ST cams) with the OEM exhaust from the GS 1000 SN.
Next a modified GS 1000 with BS 34 carbs fitted with pods and Dynojet stage 3 kit, 4 into 1 exhaust.
On both engines new valves have been fitted but no special head work done.
Here's the OEM GS 1000 ST result: 93.5 hp at the crank

The modified GS 1000 with BS carbs and 4 into 1 but normal cams: 85.1 hp at the crank

I believe I managed since to get more power out of the bike by replacing the Dynojet needles with some 5D59 I had lying around in conjunction with 147.5 Mikuni main jets....but I haven't measured it so far!

[Nessism]

Bottom line: pipe, pods, dyno tuning on a GS1100 increased hp by 4.9.





Adding a pipe alone, even if it includes airbox mods and increasing the main jet size, which I believe was suitable to get the fuel air in the proper range for full throttle usage, didn't add much HP, and could even result in a loss, depending on the specific pipe.

[koolaid_kid]

here is one of Ed's threads on pipes.

http://www.thegsresources.com/_forum/showthread.php?t=150190&highlight=pipe

You need empirical data that rejetting is required for a pipe change? All you need is a back to back compare of swapping out a 4:2 with a 4:1 and use a WBO2 sensor to record the AFR changes.

Why convolute the analysis with hp and dynos uncertainties?

No, Jim, not just a pipe. Everything, pods/pipe/jet kit.
Cycle World wrote an article that concluded pods and a pipe were wasted money and you were better off stock. They have empirical data backing up their conclusions. There is no date on the article, but it appears to be around 1980/1981.
I have been challenged to provide empirical data for my belief that if you properly do all 3 that a performance increase will be seen.

[koolaid_kid]

Bingo! Ed, the top chart is almost exactly what I am looking for. If I interpret it correctly, it is showing peak power. I really need to full rpm range to completely prove my point. Would you happen to have that data? Even a comma delimited file that I can import into Excel and create my own chart would be fine.
One question: did the bike have a jet kit installed and correctly tuned in all 3 ranges.

John, I appreciate it, but I need CV vs. CV charts. If you have any of those it would be great.

[posplayr]

Bottom line: pipe, pods, dyno tuning on a GS1100 increased hp by 4.9.

Is the 4.9 percentage or hp?

It is ironic as looking at this data, one could easily conclude "what is the point" when in reality there is a significant impact to improved acceleration (due to drop in weight)even if hp changes are negligible.

For example consider a 550 lbs bike with 200 lbs rider. A 50 lbs weight savings would account for a 7% improvement in acceleration. Even if at higher speeds the windage effects would start to dominant. For stop and go riding it should be noticeable. Add in a gearing change and acceleration could easily be improved by 15% in total. And so the quest for speed begins.......

[Nessism]

Sorry, but don't think a full dyno chart is available for that particular test. I do remember reading countless articles on pipes/pods/jetting though and the bikes typically, as in almost all cases, had a mid range power dip. The 4.9 hp advantage is next to nothing until the bike gets up and pulling hard in the last 1/3 of the rev range.

[Nessism]

Is the 4.9 percentage or hp?

It is ironic as looking at this data, one could easily conclude "what is the point" when in reality there is a significant impact to improved acceleration (due to drop in weight)even if hp changes are negligible.

For example consider a 550 lbs bike with 200 lbs rider. A 50 lbs weight savings would account for a 7% improvement in acceleration. Even if at higher speeds the windage effects would start to dominant. For stop and go riding it should be noticeable. Add in a gearing change and acceleration could easily be improved by 15% in total. And so the quest for speed begins.......

It's HP Jim.

$100+/hp

Weight savings is good. Rusting carbon steel pipes is not. Just about every carbon steel pipe I've ever seen was covered in rust down between the pipes, if not everywhere.

A nice stainless Supertrap, or something like you have is cool.

Noise is not cool. Most of the pipes that make extra power also make way too much noise. Power at the expense of noise is BAD. Not cool. Irresponsible.

[koolaid_kid]

Jim, that is horsepower, not percentage. You make a valid point, though, about the weight advantage. I will bring that up also.

Ed, it's too bad that all the data is not available.
Since the carb is the same except for jetting, would you conclude that the dip in the middle is due to the pipe? Perhaps the shape, curvature, collector design, etc.? Or could it be the needle/main transition in the CV carb?
An overall improvement of 6% peak is still far more than the Cycle World data, which saw virtually no improvement any where in the rpm range.