Author Topic: More power? (Read 14192 times)

TRXDAN · « **Reply #15 on:** April 26, 2016, 10:55:44 AM »

it doesn't feel like it's running out of fuel but if you stay in one gear too long and there's no power it seems to peek out until you shift to the next gear and it pulls hard again. So the shifts are coming on pretty quick. I'll post a video and you'll be able to hear my 250 over the banshee and you could hear how fast I go to the gears.

TRXDAN · « **Reply #16 on:** April 26, 2016, 10:56:36 AM »

https://youtu.be/hEGglOLvYi8

JesseA420 · « **Reply #17 on:** April 26, 2016, 11:05:39 AM »

gearing?

TRXDAN · « **Reply #18 on:** April 26, 2016, 11:15:45 AM »

13 42. I just put a 14 up front i havnt tried it yet

FerrinMotorsports · « **Reply #19 on:** April 26, 2016, 01:04:14 PM »

Have you enlarged the stinger on the end of the TRX11???....I run almost exactly the same setup as you and it made a difference.....But I also run a CR ignition...

TRXDAN · « **Reply #20 on:** April 26, 2016, 01:53:15 PM »

Quote from: FerrinMotorsports;66959

Have you enlarged the stinger on the end of the TRX11???....I run almost exactly the same setup as you and it made a difference.....But I also run a CR ignition...

what did you do to enlarge it?

broken1 · « **Reply #21 on:** April 26, 2016, 06:28:07 PM »

Quote from: TRXDAN;66956

13 42. I just put a 14 up front i havnt tried it yet

13/42 is about the same as 12/39 which is pretty low gearing. 12/39 is whats on my wife's R for slower tight woods riding. Maybe try a 39 or 38 rear along with the 14 front.

Jerry Hall · « **Reply #22 on:** April 27, 2016, 12:28:24 AM »

In the video it sounds like you are over-revving it on the last part of the hill. I would take one to two teeth off of the rear sprocket and see if that will keep it running closer to your peak power. I think that one tooth on the engine will be too big of a change

Advancing the timing will make it come into the power at a lower RPM but will usually make it not rev as high.

Your run on the hill was about 7 seconds long. On my dyno a TRX 11 CM becomes too restricted when the time at full throttle is more than about 3 seconds and making 60 HP or more. Full throttle for 5 seconds or more at 55 plus HP the TRX 11 CM becomes too restricted by its stinger and silencer.

The out of frame TRX 11 pipe and silencer builds more back pressure and heat in a shorter time and lower power levels.

The power, pipe temperature and time at full throttle determines the optimum restriction for any given pipe.

TRXDAN · « **Reply #23 on:** April 27, 2016, 07:46:14 AM »

Quote from: Jerry Hall;66971

In the video it sounds like you are over-revving it on the last part of the hill. I would take one to two teeth off of the rear sprocket and see if that will keep it running closer to your peak power. I think that one tooth on the engine will be too big of a change

Advancing the timing will make it come into the power at a lower RPM but will usually make it not rev as high.

Your run on the hill was about 7 seconds long. On my dyno a TRX 11 CM becomes too restricted when the time at full throttle is more than about 3 seconds and making 60 HP or more. Full throttle for 5 seconds or more at 55 plus HP the TRX 11 CM becomes too restricted by its stinger and silencer.

The out of frame TRX 11 pipe and silencer builds more back pressure and heat in a shorter time and lower power levels.

The power, pipe temperature and time at full throttle determines the optimum restriction for any given pipe.

In the video i hit 4th gear thats when the clutch was slipping making it sound like i was over revving it.

Would you recommend another pipe Jerry?
Yesterday i notice something about my pipe. When i rev it up the pipe moves like it has a lot of pressure being built up.do you get what im saying?.its mounted correctly and have good springs at the head pipe to cylinder.

etccb · « **Reply #24 on:** April 27, 2016, 11:23:28 AM »

trx11 and zeplins have been used on some fast 370 at the dunes drag strip successfully with no problems for over 20 years.

TRXDAN · « **Reply #25 on:** April 27, 2016, 11:49:34 AM »

Quote from: etccb;66992

trx11 and zeplins have been used on some fast 370 at the dunes drag strip successfully with no problems for over 20 years.

you're right etccb. maybe its just me thinking too much about this whole thing.

Jerry Hall · « **Reply #26 on:** April 27, 2016, 11:56:10 AM »

Quote from: TRXDAN;66977

In the video i hit 4th gear thats when the clutch was slipping making it sound like i was over revving it.

Would you recommend another pipe Jerry?
Yesterday i notice something about my pipe. When i rev it up the pipe moves like it has a lot of pressure being built up.do you get what im saying?.its mounted correctly and have good springs at the head pipe to cylinder.

Fix the clutch before making any changes. You cannot evaluate anything accurately with the clutch slipping.

Pipes move off of the flange due to pressure and or vibration. You cannot evaluate the optimum pipe pressure by watching the pipe move on the flange. When the pipe moves on the flange it is due to insufficient spring tension and or the pipe being improperly mounted not too much back pressure.

Adjusting pipe pressure is an experimental process that is best monitored and optimized by instrumentation and an experienced person using a dyno. Optimum back pressure is not the same for all engines and pipes!

TRXDAN · « **Reply #27 on:** April 27, 2016, 12:02:49 PM »

Quote from: Jerry Hall;66994

Fix the clutch before making any changes. You cannot evaluate anything accurately with the clutch slipping.

Pipes move off of the flange due to pressure and or vibration. You cannot evaluate the optimum pipe pressure by watching the pipe move on the flange. When the pipe moves on the flange it is due to insufficient spring tension and or the pipe being improperly mounted not too much back pressure.

Adjusting pipe pressure is an experimental process that is best monitored and optimized by instrumentation and an experienced person using a dyno. Optimum back pressure is not the same for all engines and pipes!

its been fixed Jerry, i put a new clutch kit in i not too long ago and has not slipped since.

Jerry Hall · « **Reply #28 on:** April 27, 2016, 12:13:30 PM »

Quote from: etccb;66992

trx11 and zeplins have been used on some fast 370 at the dunes drag strip successfully with no problems for over 20 years.

The problem is not how long the guys have been using these pipes. The problem is, guys are getting more power from these cylinders than they were 25 years ago using these same pipes. As the power goes up, the back pressure increases. My testing is showing that some guys engines are reaching this critical pressure level and is causing detonation and in severe cases a reduction in power as compared to the same pipes that have the restriction optimized for the type of riding.

The same engine and pipe restriction optimized for 300 ft drags will require a smaller restriction than the same engine with the pipe restriction optimized to race up a sand hill like TRXDAN was on in his video.

TRXDAN · « **Reply #29 on:** April 27, 2016, 12:21:46 PM »

now that make sense about making more power now day. what do you recommend Jerry?