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Discussion Starter · #1 ·
When I ordered my Bikeman pipe mod they said (on the phone) that they recommend a fuel pressure reducer as the newly modified pipe will increase fuel at WOT. So I installed both the pipe and pressure reducer, leaving the reducer "open", or stock fuel pressure....and in theory "fat".

Looking over past dyno reports from another sled dyno'd at Dynotech....a pipe comparison was done on a stock engine and the run with the Bikeman modded pipe actually showed less fuel (BSFC and Fuel lb/hour) than the stock set up.

I realize this is only one sled on the dyno, just not sure what to believe. Have not had time to dyno my sled, was hoping for some feedback in the meantime regarding what others have done???

My sled is an 05 F7 EFI. Has D&D Y pipe, Bikeman pipe mod, fuel pressure reducer. Air box etc...fully stock.
 

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<div class='quotetop'>QUOTE (im4snow2000 @ Jan 22 2007, 11:07 AM) <{POST_SNAPBACK}></div>
When I ordered my Bikeman pipe mod they said (on the phone) that they recommend a fuel pressure reducer as the newly modified pipe will increase fuel at WOT. So I installed both the pipe and pressure reducer, leaving the reducer "open", or stock fuel pressure....and in theory "fat".

Looking over past dyno reports from another sled dyno'd at Dynotech....a pipe comparison was done on a stock engine and the run with the Bikeman modded pipe actually showed less fuel (BSFC and Fuel lb/hour) than the stock set up.

I realize this is only one sled on the dyno, just not sure what to believe. Have not had time to dyno my sled, was hoping for some feedback in the meantime regarding what others have done???

My sled is an 05 F7 EFI. Has D&D Y pipe, Bikeman pipe mod, fuel pressure reducer. Air box etc...fully stock.[/b]
Uhhh, is it just me or is anyone else confused as to how a change to the exhaust system can increase fuel flow?

You may increase the need for fuel (as in you need MORE fuel flow), but then you would not want a RESTRICTOR, you would want a regulator that would allow you to add more fuel, not restrict it.

I have the BMP pipe mod and a fuel restrictor (and a 2.5 degree timing key). I also run the restrictor wide open (as in NOT restricted). I have about 44psi at idle, but it drops to about 40 at WOT. I am currently still "pulling" on the other F7's (all stock) that I ride with so I see no need to lean it out.

BMP has dyno sheets on their site, why would you go to dynotech?

Finally, yes, using the fuel restrictor should result in lower Brake Specific Fuel Consumption because you are restricting fuel therefore lowering the fuel consumption.
 

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Everything I've ever seen says the pipe does in fact reduce BSFT or lean it out.
 

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Discussion Starter · #5 ·
<div class='quotetop'>QUOTE (bigblock2stroke @ Jan 22 2007, 12:35 PM) <{POST_SNAPBACK}></div>
<div class='quotetop'>QUOTE (im4snow2000 @ Jan 22 2007, 11:07 AM) <{POST_SNAPBACK}>
When I ordered my Bikeman pipe mod they said (on the phone) that they recommend a fuel pressure reducer as the newly modified pipe will increase fuel at WOT. So I installed both the pipe and pressure reducer, leaving the reducer "open", or stock fuel pressure....and in theory "fat".

Looking over past dyno reports from another sled dyno'd at Dynotech....a pipe comparison was done on a stock engine and the run with the Bikeman modded pipe actually showed less fuel (BSFC and Fuel lb/hour) than the stock set up.

I realize this is only one sled on the dyno, just not sure what to believe. Have not had time to dyno my sled, was hoping for some feedback in the meantime regarding what others have done???

My sled is an 05 F7 EFI. Has D&D Y pipe, Bikeman pipe mod, fuel pressure reducer. Air box etc...fully stock.[/b]
Uhhh, is it just me or is anyone else confused as to how a change to the exhaust system can increase fuel flow?

You may increase the need for fuel (as in you need MORE fuel flow), but then you would not want a RESTRICTOR, you would want a regulator that would allow you to add more fuel, not restrict it.

I have the BMP pipe mod and a fuel restrictor (and a 2.5 degree timing key). I also run the restrictor wide open (as in NOT restricted). I have about 44psi at idle, but it drops to about 40 at WOT. I am currently still "pulling" on the other F7's (all stock) that I ride with so I see no need to lean it out.

BMP has dyno sheets on their site, why would you go to dynotech?

Finally, yes, using the fuel restrictor should result in lower Brake Specific Fuel Consumption because you are restricting fuel therefore lowering the fuel consumption.
[/b][/quote]


Bigblock2storke,.......just passing along what they told me (ie, pipe will benefit from fuel pressure reducer as pipe makes wot fatter)....seems counterintuitive to me, but that's what they said and then sold me a reducer.

Guess I'll keep my reducer set to "full flow" until I can get it to a dyno. Not sure of my pressure at wot yet, exhuast is off for other reasons.....will find out soon.
 

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Changing your pipe has no effect at all on how much your fuel your system puts in. Changing the pipe will NOT increase fuel at WOT. I can buy the fact that it can change the fuel/air ratio a bit and that the 2 mods can work together to make a sled run better.
 

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Well I'll tell you what...two weekends ago I ran BMP ported F7 cylinders on my sled(long story,but just for the weekend)with cut head,and new F7 Fat-azz pipe and ran stock fuel pressure with '03 box and had to run my 7200 and 7800 rpm settings in my Boondocker box at -10 and -15 to make it run it was soooo rich with stock fuel pressure and Erich(Bikeman) ran an '05 or'06 box on his and was running around -6 and -9 so they do run richer,yes and still the EGT's only made it to 1050-1100 on my sled my 900 runs at 1200-1250 so go figure!!
 

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I was also told the same thing when I had my pipe mod done. I told them I was running a 290 jet in my reducer and was told this would be fine.
 

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<div class='quotetop'>QUOTE (cjt @ Jan 22 2007, 05:36 PM) <{POST_SNAPBACK}></div>
Well I'll tell you what...two weekends ago I ran BMP ported F7 cylinders on my sled(long story,but just for the weekend)with cut head,and new F7 Fat-azz pipe and ran stock fuel pressure with '03 box and had to run my 7200 and 7800 rpm settings in my Boondocker box at -10 and -15 to make it run it was soooo rich with stock fuel pressure and Erich(Bikeman) ran an '05 or'06 box on his and was running around -6 and -9 so they do run richer,yes and still the EGT's only made it to 1050-1100 on my sled my 900 runs at 1200-1250 so go figure!![/b]

How's the ported sled with cut head run.

I want to cut the head (another sleeper, can't tell from the outside mod) for sure. The porting is a little too much cash for me right now, but if I put new rings in at around 5k miles, I might be able to swing it.

Just interested in any performance gains.
 

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<div class='quotetop'>QUOTE (bigblock2stroke @ Jan 23 2007, 12:03 PM) <{POST_SNAPBACK}></div>
<div class='quotetop'>QUOTE (cjt @ Jan 22 2007, 05:36 PM) <{POST_SNAPBACK}>
Well I'll tell you what...two weekends ago I ran BMP ported F7 cylinders on my sled(long story,but just for the weekend)with cut head,and new F7 Fat-azz pipe and ran stock fuel pressure with '03 box and had to run my 7200 and 7800 rpm settings in my Boondocker box at -10 and -15 to make it run it was soooo rich with stock fuel pressure and Erich(Bikeman) ran an '05 or'06 box on his and was running around -6 and -9 so they do run richer,yes and still the EGT's only made it to 1050-1100 on my sled my 900 runs at 1200-1250 so go figure!![/b]

How's the ported sled with cut head run.

I want to cut the head (another sleeper, can't tell from the outside mod) for sure. The porting is a little too much cash for me right now, but if I put new rings in at around 5k miles, I might be able to swing it.

Just interested in any performance gains.
[/b][/quote]


I was VERY impressed!!! The dyno sheet with the porting and new F7 Fat-Azz pipe is at 167.2 hp and 111 ft.lbs.torque, and it felt like every bit of it! We ran just past 1/4 mile but less than 1/2 mile with picks and the sled slammed down and ran 127 mph on GPS and speedo! It out ran many much bigger sleds,Mach z's,actually beat a 1108 hooper sled in 1000' and most other sleds at Cedar Lake two weeks ago,there is a post on dootalk under Machz forum(might be a couple pages back now) If I didn't already have the 900 I would have this set up in my sled for-sure!!
 

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<div class='quotetop'>QUOTE (cjt @ Jan 23 2007, 03:26 PM) <{POST_SNAPBACK}></div>
<div class='quotetop'>QUOTE (bigblock2stroke @ Jan 23 2007, 12:03 PM) <{POST_SNAPBACK}>
<div class='quotetop'>QUOTE (cjt @ Jan 22 2007, 05:36 PM) <{POST_SNAPBACK}>
Well I'll tell you what...two weekends ago I ran BMP ported F7 cylinders on my sled(long story,but just for the weekend)with cut head,and new F7 Fat-azz pipe and ran stock fuel pressure with '03 box and had to run my 7200 and 7800 rpm settings in my Boondocker box at -10 and -15 to make it run it was soooo rich with stock fuel pressure and Erich(Bikeman) ran an '05 or'06 box on his and was running around -6 and -9 so they do run richer,yes and still the EGT's only made it to 1050-1100 on my sled my 900 runs at 1200-1250 so go figure!![/b]

How's the ported sled with cut head run.

I want to cut the head (another sleeper, can't tell from the outside mod) for sure. The porting is a little too much cash for me right now, but if I put new rings in at around 5k miles, I might be able to swing it.

Just interested in any performance gains.
[/b][/quote]


I was VERY impressed!!! The dyno sheet with the porting and new F7 Fat-Azz pipe is at 167.2 hp and 111 ft.lbs.torque, and it felt like every bit of it! We ran just past 1/4 mile but less than 1/2 mile with picks and the sled slammed down and ran 127 mph on GPS and speedo! It out ran many much bigger sleds,Mach z's,actually beat a 1108 hooper sled in 1000' and most other sleds at Cedar Lake two weeks ago,there is a post on dootalk under Machz forum(might be a couple pages back now) If I didn't already have the 900 I would have this set up in my sled for-sure!!
[/b][/quote]

Sounds like a super sleeper setup. Might have to look into it a little deeper.
 
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