Significant loss of RPM after adding head to SLP single pipe.

[Ken Climb]

I've been running the SLP single pipe the last 200 miles or so. Really happy with it.
Decided to add the 6-8,000' slp head but found the sled dropped 5-600 RPM.
testing at 6,000'

SLP single pipe, can & air intake:

10-68 poo weights blue pink slp spring in clutch, stock driven =8,400 under load, Greatly improved top-end power but quite a drop in bottom end power and snap.

Then added the head and a black/purple slp spring in the secondary

now I'm only pulling 78-7,900 under load.

The addition of the head greatly improved the bottom end. I thought I might loose a little rpm with the higher compression.... but not 500+

Any thoughts?

 

[Sheetmetalfab]

Overev makes a soft rev limiter.

 

[Dootimes2]

Did you add a fuel controller? I think they require one with your set up.

 

[Ken Climb]

No fuel controller.


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[snobyrd]

I had rpm loss as well,about 7700, but at start of the day with a 56 42 blk purple, i was reving perfect 8300, later that day,7700, not sure why, i brought the sled to the dealer , was told tps was out, they checked everything else out and was told all else was good. When i lost rs, it felt like the power valves were not opening, ill know next week if the prob is gone.

 

[dragonfire]

SLP HEAD

No fuel controller.


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I installed head at lower elevation after having ran SLP pipe and silencer. I also had the Bully Dog and lost 3 to 400 rpm. Next day I took the head and bully dog off and just went back to pipe & silencer. RPMS came back and sled ran good again. I know of 2 other guys with same experience. Have always had good luck with SLP in the past.

 

[Ken Climb]

I think In most cases you do loose rpm when raising compression, I was just surprised at how much I lost.
8400 down to 7900.
Today I tried the mtx weights.
68 g weights with 3 g in the heal and 1 g in the outer. Blue pink primary spring, black purple secondary.
With this I'm pulling 8200 under load at 6,000'.
Crisp snappy bottom end explosive midrange but still lacking a touch on top. It felt so good before (with just the pipe) spinning 8400.
This is getting real close. I think I'll take the heal down to 2 g and try 2g in the outer. What do you guys think?


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[NoSoup4U]

I think In most cases you do loose rpm when raising compression, I was just surprised at how much I lost.
8400 down to 7900.
Today I tried the mtx weights.
68 g weights with 3 g in the heal and 1 g in the outer. Blue pink primary spring, black purple secondary.
With this I'm pulling 8200 under load at 6,000'.
Crisp snappy bottom end explosive midrange but still lacking a touch on top. It felt so good before (with just the pipe) spinning 8400.
This is getting real close. I think I'll take the heal down to 2 g and try 2g in the outer. What do you guys think?


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I think with 2 grams in the belly and 2 grams in the tip you will pull less rpm than 3 grams in the belly and 1 gram in the tip. If you want to pull more rpm, go to 2 grams in the belly and 1 in the tip.

 

[MountainPaco]

I see you are nearby. Touch base with Dr. John in Kelowna. He has this setup out there with real good results. I was there and he was fine tuning the setup Saturday. MP.

 

[MBR44]

I had rpm loss as well,about 7700, but at start of the day with a 56 42 blk purple, i was reving perfect 8300, later that day,7700, not sure why, i brought the sled to the dealer , was told tps was out, they checked everything else out and was told all else was good. When i lost rs, it felt like the power valves were not opening, ill know next week if the prob is gone.

I will be interested to find out what your dealer says. Mine did the same thing last time out. I changed nothing. I was 8250 all weekend then all of a sudden it went to 7800. I took off the slp resistor and my codes stopped but it revs 7900 and if I am on it for a long time it will climb to 8050. It seems to have lost all the snap up top, like the power valves aren't opening.

 

[green_denali]

I think In most cases you do loose rpm when raising compression, I was just surprised at how much I lost.
8400 down to 7900.
Today I tried the mtx weights.
68 g weights with 3 g in the heal and 1 g in the outer. Blue pink primary spring, black purple secondary.
With this I'm pulling 8200 under load at 6,000'.
Crisp snappy bottom end explosive midrange but still lacking a touch on top. It felt so good before (with just the pipe) spinning 8400.
This is getting real close. I think I'll take the heal down to 2 g and try 2g in the outer. What do you guys think?


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Take out the 1 gram in the outer, & only put one gram in the heal.


1 gram or tip weight equals 100 rpm's
1 gram of heal weight equals 50 rpm's

 

[die hard poo]

Seems like some of these symptoms sound like the RPM loss that I have. I can't seem to get above 7900rpm stock now. Its at the dealer now. If you find something not related to your mods please share. If you added more horsepower mods, then you should be gaining rpm, not losing.

 

[dragonfire]

I think In most cases you do loose rpm when raising compression, I was just surprised at how much I lost.
8400 down to 7900.
Today I tried the mtx weights.
68 g weights with 3 g in the heal and 1 g in the outer. Blue pink primary spring, black purple secondary.
With this I'm pulling 8200 under load at 6,000'.
Crisp snappy bottom end explosive midrange but still lacking a touch on top. It felt so good before (with just the pipe) spinning 8400.
This is getting real close. I think I'll take the heal down to 2 g and try 2g in the outer. What do you guys think?


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I tried changing rivets in the mtx weights until I got the RPMS back and I was still 4-5 sled lengths behind the sled that I was the same as with the pipe on only. I was at sea level so there was no increase in compression. Going slower and having less RPM with head = less horsepower. Just my observation after many hours of work and frustration,plus money I spent on this to go slower.In the end I run just the pipe with much better performance and I am happy.

 

[Ken Climb]

I suppose people who installed the stage 3 pipe and head wouldn't notice this.
It's just us guys that had the pipe first then later after adding the head noticed the rpm and top end loss.


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[steepndeep800]

1 other thing guys is the belt seems to loose performance quickly once it gets about 5-700 miles on it.
adjusting the sheaves does not fix it. It's like the belt stretches long or something in the compound of the belt.
Also Rollers have been a issue on the primary clutches.

 

[dragonfire]

I suppose people who installed the stage 3 pipe and head wouldn't notice this.
It's just us guys that had the pipe first then later after adding the head noticed the rpm and top end loss.


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I agree because I sure wanted it to work . I was hoping for a little more power but was disappointed when I lost after being so happy with how the pipe worked.

 

[Old Scud-doo]

Not trying to start anything, but I know on my pro it ran great at 1000 miles until I put the head on then it had too much compression for the flaking rings and knifing Pistons. Anyone actually check their Pistons and rings? I hope that isn't the problem but it could be blow past the rings if they are starting to go bad. Otherwise, good luck.

 

[BBP]

I think I would put the clutching back exactly like it was prior to the head change. That way you will know whether it was the head or secondary spring that lost performance. I would also start with a new belt as someone else suggested.

 

[BBP]

You might also try adding a couple gallons of race fuel to see if it's a fueling issue. Do one thing at a time so you know what changes what.

 

[paulharris]

I've been running the SLP single pipe the last 200 miles or so. Really happy with it.
Decided to add the 6-8,000' slp head but found the sled dropped 5-600 RPM.
testing at 6,000'

SLP single pipe, can & air intake:

10-68 poo weights blue pink slp spring in clutch, stock driven =8,400 under load, Greatly improved top-end power but quite a drop in bottom end power and snap.

Then added the head and a black/purple slp spring in the secondary

now I'm only pulling 78-7,900 under load.

The addition of the head greatly improved the bottom end. I thought I might loose a little rpm with the higher compression.... but not 500+

Any thoughts?

did you pick up the phone and call SLP?