4 long stacks: another prespective.

[OB_Dirty Pete]

Just dynoed the Busa after changing to 4 long stacks. Same dyno, same fuel, same prep same weather. I have Akra, full box cut, BMC and 100% synth oil.

In SAE corrected RWHP, the bike went from 165 to 162.1 peak rwhp. However, it makes 2 more rwhp ALL the way up the curve until 8500, where it quite graphically tucks under the stock stack setup by 3 ponies.

Previous correction factor: 104. Today's correction factor 102 (barometric pressure was the only difference). Uncorrected SAE peak rwhp was identical, with the 4 stacks showing 2 more horse all the way up the curve until peak where it's the same.

I'll reserve judgement until the Yosh cams are in. It's nice to have the mid range punch for the twisties.

This of course is only my particluar bike on this particular day. These results conflict with what MTRHD and Frank Adams are getting, but that doesn't make their results wrong or mine right. It's just one more bit of evidence to consider.

[This message has been edited by Dirty Pete (edited 15 April 2000).]

 

[Gixx1300R]

A Power Commander might make up the difference in the 3 horsepower defeciency up top.Did u remap with a Yosh box after you installed the longer stacks?

 

[OB_Dirty Pete]

I think you're right, I hadn't thought of that. My new PC2 from Chuck should be at my office now. I'll leave the stacks in until I can lean out the top end much more. I'm currently -5 top and mid; set by a Yosh box.

Frank thinks I should be much leaner on top, and my tailpipe agrees.

Thanks for the reminder Nick.

[This message has been edited by Dirty Pete (edited 15 April 2000).]

 

[Guest]

What it does is cloud the issue a bit. I was under the impression that long stacks were a proven commodity.

 

[OB_THE MOTORHEAD]

-5 holyshhit you're lean.run stock or fatter.i see whats up here if they flow more you maybe leaning out.never ever go - in the yosh mapping.why would you go less than stock?thats insane.i have my 99 at +1+1+1pc2 and the same on my 2000.this puts you at mid 12-1 a/f ratio.i goy way too many pulls not to haave this gig down.plus over 100 passes with different combos for real world tests try +5+0+_0 then work your way up.you'll see.don't do that any more .that - stuff is bullsshit see here http://albums.photopoint.com/j/View?u=111029&a=812683&p=19187173&Sequence=0

[This message has been edited by THE MOTORHEAD (edited 15 April 2000).]

 

[OB_Dirty Pete]

MTRHD I'll try it every which way and report back. It may be that my tail pipe is black because I run mostly in the mid range. You may well be right about pumping more fuel into the top end.

I'll soon have the tools to figure it out. Your advice is always valued and appreciated by me and, I'm sure, many others.

 

[OB_valklex]

DP, newer bikes, especially '99s and '00s, are as lean as they can be to meet EPA requirements. I would NEVER go any leaner under any circumstances; reliability would be compromised. The reason of your black exhaust might be that you removed the PAIR valve, and it's being stained during deceleration. If you want to try the lean route, strap your bike to an EGA machine once you finish all hardware modifications and play with the PC2 the safe way. Hey DP, how did the GoBig dispute end? You can use my e-mail if you prefer.

 

[OB_Dirty Pete]

Thanks Animal, I will definitely do that from now on.

 

[Frank Adams]

Now thats some Good info!!

 

[OB_Dirty Pete]

Yeah I'm sorry I can't post the chart. I've been posting my charts up til now, but this dyno guy's unable to print out right now. Ticks me off because I like to have a long look at the curve comparisons. My next dyno will be with cams in. Hopefully he'll be printing by then so I'll be able to post curve overlays so we can all see exactly what the cams do.

Valk the LAbusas situation is fine now, although one highly respected member has recently withdrawn from the board due to freedom of speech issues. It's a wild ride over there...the internet on the edge for sure. People are testing the limits of free speech constantly because we all realize that we've never had total freedom before in any other context of life.

I'm learning. We're all learning.

 

[OB_THE MOTORHEAD]

i think if you use cams etc.aluminum stacks maybe the best for top end?the frequencies are different.i'm checking on custom stacks now for different applications.

[This message has been edited by THE MOTORHEAD (edited 16 April 2000).]

 

[Frank Adams]

How are you going to get aluminum stacks to seal themselfs in the Airbox?

 

[OB_THE MOTORHEAD]

foam inserts

 

[OB_Dirty Pete]

Valklex, that's an EXCELLENT point about the tailpipe reading rich because of the PAIR system removal. Thanks. I should be looking at my plugs after some hard riding; not my tailpipe.

 

[Frank Adams]

Dp, if your looking for a topic that could go on for a while, this one might be one??

If you would post your graph it would help!

It's not a good policy to dial a bike in from what your pipe shows...this is something good to do if your looking for oil residue.
Whats in your pipe could be from fuel with the wrong burn rate?

Dp, I want you to know that if 5+5+0 & 0+5+1 works for this guy, doesn't mean it's going to work for you!
You live in a different climate from Me or John Doe in Texas...so don't use whats working for them unless they're living up the street from you...dial your bike to the dyno.
And keep in mind that your Busa will probably lean out even more in the real world when the Ramair starts forcing air. Thats something you don't see on the dyno..

Keep us up on the details!

 

[OB_Animal]

DP,

If it was a Dynojet you went to, just ask the operator to put your run-data on floppy for you (3 Kb each I think) and download the viewer software for free from Dynojet themselves.
You can look/compare on your own PC as long and often as you like (overlaying runs, seeing torque/HP versus rpm/speed and using printscreen and then later pick it up with graphics program from clipboard you can even print yourself with the old Dynojet viewer (the new one has print functionality but is a bit different, some think less, in other functionality areas).