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Discussion Starter · #241 ·
when looking into harmonics, generaly you want the second and third harmonic the most. they tend to be the smoothest and most beneficial of course it all depends on the motor. i have tested my first design and found the the harmonics all wrong but the but even worse was the return harmonic canceling some resonance. i am looking (and working with our audio engineer) to try to find the correct balance for this engine. even the suzuki stacks had some cancelation but it was limited because of small size. i will try to update more often on how this is going.
 

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Double Dumb Ass
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Cool, thanks for the update. Please let us know what works out.
 

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Double Dumb Ass
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I picked up a book on fluid mechanics from the library today. I'll see if that helps with some ideas concerning velocity stacks and RAM air.
 

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Secondary Throttle Plate Modification

Prophet,

I just found your thread on modifying the secondary throttle plates on the SV, and I am very appreciative of the research that you and others on this site have put into this issue. I have an '03 SV650N, so some of the technical details I have found on this site, I have to filter with that in mind. I did notice that you mentioned a four 1/4" hole pattern should work for the 650, and I am anticipating trying that out.
You also mentioned painting the separater foil piece. Would you have any recommendation as to what type of paint to use? Also, would you recommend 1/2" holes in the separater foil pieces to be used on the SV650, or something smaller in diameter?

Thanks,
HarryD
 

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Well, I finished my intake chambers last night and hit the track tonight. All in all I didnt notice any difference.

I did have some problems making the chambers however, that and I didnt drill the hole in them yet. The biggest problem is that the thin aluminum is a PITA to cut out and still have it flat. Do you think that the lack of an improvement is due to the lack of a hole, or due to the fact that the plat is no longer prefectly flat?

I need to find somebody around here who might be able to cut some of these out with a water jet, I wonder if they could cut some secondary throttle valves at the same time.

Oh, BTW, my bike is running rich, and I have not set the TPS, or the secondaries, or synced the TB's, so dont take my results as a failure of the design.
 

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Prophet,

The throttle shaft on the secondary is HUGE. Do you feel that thinning the shaft would show any sustantial difference? That thing has to be 6mm or so thick, I would imagine that the shaft itself could be thinned to 2mm or so, and properly shaped (aka airfoil) with no concerns for strength. Also, if the shaft was thinned do you feel that the size or shape of the holes in the STV's would need to be changed?

The same thinning could be done to the primary throttle shafts as well, if it would show a difference.
 

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Discussion Starter · #247 ·
The air foils need to be flat and have no hole in them if you have the holes in the STV. Also the leading and trailing edges of the foils must be sharpend. As for the thinning of the shafts, i would say go for it. Anything that improves air flow will have some gain. Might not be a seat of the pants gain but the dyno will show a smoother power and torque line. Anytime you can improve the way an engine breaths is a good thing. Removing an obstruction to air flow, like the throttle shaft, is good.

I have been doing testing on some local 650's for foil and STV mods. So those of you with 650's will soon have a pattern size and other mods to try. I will have the final results by this coming saturday.
 

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wow, this thread is intense!!! I have a 650, i'm working on it rite now, and I wanna change the whole intake...
1.bmc air filter
2.cut the air box
3.drill the holes on the two things (secondary throttle valve) , do we have to drill wholes on the valves below these valves also?
4.now my question is, is the billet velocity stacks from factory pro worth it? if you tried them prophet, would appreciate your point of view on these product!!

thx for your efforts!!


btw what exaclty is the air foil?

another thing, is it normal that it smells like gaz in the airbox, very noticiable!!
 

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wow, this thread is intense!!! I have a 650, i'm working on it rite now, and I wanna change the whole intake...
1.bmc air filter
2.cut the air box
3.drill the holes on the two things (secondary throttle valve) , do we have to drill wholes on the valves below these valves also?
4.now my question is, is the billet velocity stacks from factory pro worth it? if you tried them prophet, would appreciate your point of view on these product!!

thx for your efforts!!


btw what exaclty is the air foil?

another thing, is it normal that it smells like gaz in the airbox, very noticiable!!
offtopic: :yes: i think that the velocity stack are worth. i self got the 35/70 stacks on my 650s and after i installed them i could feel a good improvement in the mid range.
i also got a bmc airfilter but the only improvement it made that it's a little bit louder than stock.



but now back ontopic:

what are the results/setup on the tests for the 650?
 

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wow, this thread is intense!!! I have a 650, i'm working on it rite now, and I wanna change the whole intake...
1.bmc air filter
2.cut the air box
3.drill the holes on the two things (secondary throttle valve) , do we have to drill wholes on the valves below these valves also?
4.now my question is, is the billet velocity stacks from factory pro worth it? if you tried them prophet, would appreciate your point of view on these product!!

thx for your efforts!!


btw what exaclty is the air foil?

another thing, is it normal that it smells like gaz in the airbox, very noticiable!!
I certainly hope you don't drill holes in the main throttle plates (lower ones)! Be in for a very interesting surprise if you did! And of course it smells like gas, the crankcase vents here, as well as 2 rather large throttle bodies with injectors in them sittn there. The goal in drilling the uppers is to partly disable some of the factory maltune, as well as reduce air drag. That's the simplified version. The fact that the velocity stacks are billet has nothing to do with performance, Trick is a set that are tuned properly for your bike and riding habits. Wasn't there something about the DL1000 having longer velocity stacks? Lighter weight rubber ones for me any day if they work well!
 

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KNEE DRAGGER
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I have been following this thread and looking at data and making spread sheets and such... I was having a math issue with a few formulas some time back so I started to look at it again today.

So knowing that the formula for HP is

HP = (Torque X RPM)/5252

Some of the numbers you have given do not work out here and may be part of my problem when using these numbers you have posted.



base bike: 2007 SV1000s custom mufflers, custom fiberglass airbox, TRE, UNI air filter:
MAX:
111.6 HP @ 9675
70.3 ft./lbs. @ 7650

Other points:
99.8 HP @ 7650
64.3 ft./lbs. @ 4800
107.8 HP @ 10250
65.6 ft./lbs. @ 10250
Here, the numbers you have given at @7650RPM do not match (70.3 X 7650)/5252 = 102.4HP, but you later state data that 99.8HP @7650 which is 68.5 torque

The 10250rpm data does not seem to calculate correctly either (65.6 X 10250)/5252 = 128.0HP and using the other numbers 107.8HP @10250 would mean the bike makes 55.2 Torque





*Then I took the STP's and got a little creative...I drilled a few 5/8 in. holes:
MAX:
113.9 HP @ 9990
71.2 ft./lbs. @ 6850

Other points:
100.1 HP @ 7650
64.7 ft./lbs. @ 4100
112.3 HP @ 10250
69.5 ft./lbs @ 10250
The numbers here are telling me that (69.5*10250)/5252 = 135.6HP

There are several other sets of number you have reported that also do not calculate correctly according to my math either. Can you please clarify this discrepancy? Corrected vs Non Corrected? Is my math incorrect?

Thanks
-MS
 

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ok so earlier in this thread i said i was chambering my intake well here it is.
basicly i have used this method on performance cars with gains of 2-4 HP and 3-5Ft.LBS. on the smaller engines (1.4L-2.0L).
so its really easy to do, i used the thinnest aluminum sheet i could find and went to town. no specific meassurements just 1/2 inch past the top of the intake stacks is needed. the drawings show the rest. as for the width, make sure you have enough to slightly cut through the rubber intake stack and rest on the edge of the throttle body itself.the "legs" are to insure it wont move beyond that point. the best thing to do is to remove one of the stacks and measure that. this is a proven air flow amplifier. it will decrease turbulance and increase air speed and pressure. the total cost of this for me was $1.75, i used a 1'x1' square of aluminum. i couldnt get the dyno today so i will set it up for next weekend and see what it shows. so far i like the smoothness and willingness to keep accelerating past the normal 9800 RPM drop off. someone else try this (darrindietrich) and tell me what you think. i would like to get as many opinions on the modifications i have shown you all, just to know what you think.
Could somebody write the dimension of the air foil?

Will it work at stock TB (no drilling)?
http://www.sv-portal.com/forums/attachment.php?attachmentid=55963&d=1224368042
 

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Hi Guys

Thanks for a great thread and a special thanks to Prophet. :punk:

Drilled my holes this weekend - Did it better than I thought I would.(w00t)
Had a lot of traffic this morning to work, but will really test Suzi's performance this coming weekend - doing a 500km trip.

Appreciate you guys time and efforts to share.:niceone:

Stay on 2 wheels
Ciao
 

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Sorry to dredge up an old thread but, I just fitted power commander and was blowing out air filter when I noticed something interesting. STV's are wide open after running bike for a few moments. Checked linkage to make sure that nothing has fouled it and seems clear, just resistance from servo motor so not wanting to force the linkage closed to see if it reopens. Has anybody else observed same?

I haven't ridden bike yet but am about to. I'll post up findings after that.
 

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Doesn't seem to be affecting the running on a quick squirt around the block. Seems a little more gutsy and also seems to be moving at the sector arm attached to the servo motor in small increments in response to the throttle. Any thoughts?
 

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Check the secondary throttle position sensor. Mine was doing somthing similar and I found out the sensor was bad. This thread has the instructions on the first page I Think.
 

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Just drilled the holes. 8 5/16' holes in the 1-2-1 pattern. Stock airbox still but with the snorkel removed. Don't want to cut the lid up just yet. Stock air filter but I also removed the screen from the back side of it until I get a better filter. Should help flow a little. Haven't done the wind vanes yet, need to get materials. have Devil bolt on cans but no Power Commander yet. Bike fired right up and idled as normal thru the whole operating temp range. About to take her out for a spin to see how she feels now. Will report back.

Oh yeah, 2 year old thread revival FTW!!
 

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Back from the test ride. Happy with the mod overall. Nothing earth shattering in the power but the bike is overall much smoother and goes thru the rev range quicker as previously reported. Seems to fire up a little easier too. I think the STV holes will definitely make future mods that much better as I do them.

This thread should definitely be stickied as it's an excellent mod for any SV1000, stock or modified.
 

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Unsure on drilling the stv's but I can say without a doubt that the Velocity Stack chambers, the plates, have no effect. Did back to back dyno runs, 3 wih and 2 without and there was exactly zero difference in the dyno runs regardless of if the plates were fitted.

I did a bit more research on the plates while I was making the and found that Boysen makes a set for Harley's and they have been shown to provide no real WOT performance benefits (about a 1% power increase). One unsubstantiated report did state they improved part throttle power but I have seen nothing else to back that up, at least not for butterfly throttle bodies. I will say they have been shown to significantly improve flatside carburetor operation, but how they work on flatsides would have no correlation to butterfly carbs or throttle bodies.

My only other qualm is that as soon as someone questioned prophets dyno results he left and never returned, nor answered any PM, hardly conclusive but still it doesn't help understand why his dyno results didn't add up.

Bottom line, I had it proven on my own bike, in front of my own eyes, that the chambering plates did NOT add power anywhere at WOT.
 
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