 Volocity stack design considerations??, for my mickey mouse ITB's |
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| dstar |
 Apr 7 2006, 08:42 AM
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#41
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Member  Group: Members Posts: 196 Joined: 19-January 06 From: Ramstein, Germany Member No.: 5,438 Region Association: Germany  |
I've been doing that to my Dell/IDF stacks for years. Four cuts with a band saw and you're done. It gives the reversion pulse an out, to keep from disturbing the air flow that is already headed in the direction of the intake. How does this idea work, you ask? Physics folks, simple physics. (IMG:http://www.914world.com/bbs2/html/emoticons/laugh.gif) Don |
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| Mueller |
Apr 7 2006, 04:31 PM
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#42
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914 Freak! Group: Members Posts: 17,146 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None 
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taken from press release for 2003 GSX-R 1000 hmmm.....good excuse to get the "A" axis (4th) running on my mill (IMG:http://www.914world.com/bbs2/html/emoticons/smash.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/welder.gif) |
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| spunone |
Apr 7 2006, 04:54 PM
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#43
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Senior Member Group: Members Posts: 945 Joined: 6-April 04 From: Anaheim CA Member No.: 1,901 Region Association: Southern California |
Sample stack headed out today UPS have fun (IMG:http://www.914world.com/bbs2/html/emoticons/smash.gif)
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| Mueller |
Apr 7 2006, 05:27 PM
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#44
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914 Freak! Group: Members Posts: 17,146 Joined: 4-January 03 From: Antioch, CA Member No.: 87 Region Association: None
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(IMG:http://www.914world.com/bbs2/html/emoticons/pray.gif) thanks...I'll post pics as soon as I get it.... |
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| Thorshammer |
Apr 7 2006, 11:06 PM
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#45
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Senior Member Group: Members Posts: 749 Joined: 11-November 03 Member No.: 1,335 |
Since I worked for Suzuki for 5 years, I thought I might comment on this particular situation. Yes, the slot in the rubber velocity stack was to reduce the intake reversion on this model, The 2003 had different cams that caused some minor fuel distribution issues we worked out by doing this simple mod. It does not work in all applications. The intake port velocity on this engine is completely different than that of the 914 4/6engine. Also a GSXR1000 will regularly spin to 12,600 rpm. None of us ever will, or at least we will not have any straight valves after that. This mod would be an R&D affair. For GSXR 1000 race engines I build, we remove these stacks and install a stack that is a touch shorter, with a 12mm rounded edge which increases flow and changes the torque peak. The stack is also void of all slots unlike the standard piece. As far as 4D to determine the correct radius for the velocity stack bellmouth, this would be a good starting point, I checked some of the ones I have and they range from 3.5D to 5D. Interesting. I wish I could give you a reason why I arrrived at the sizing I did, but I don't. This is one area we have not discussed, and I have a trial set for my next dyno run. I really think aircleaners are very important, But I have glued a upside down top shaped piece of plastic to the under side of the air box pointed towards the carb velocity stack. I am hoping to guide some more air into the carb without restricting it. Stole the idea from Buell motorcycles. We'll See! Erik Madsen |
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| Rick_Eberle |
Apr 8 2006, 11:20 PM
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#46
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Member Group: Members Posts: 390 Joined: 14-January 04 From: Geelong, Australia Member No.: 1,558 |
Wouldn't a 2.0 turning at 6000RPM be moving a similar amount of air as a 1.0 at 12000RPM? |
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| Thorshammer |
Apr 9 2006, 08:56 AM
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#47
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Senior Member Group: Members Posts: 749 Joined: 11-November 03 Member No.: 1,335 |
Actually, No.
Volumetric efficiency of the GSXR vs the 914 engine is significantly different. The GSXR will make 172 hp at the countershaft whereas the 914 will make ? for a 2.0 to make 172, it would be a very well tuned 2.0 liter. But to put things in a cc/hp perspective, a 2.0 liter 914 engine would make 344 hp to be an equal amount of HP per cylinder. However the frictional losses and thermal differences between these engines change everything. CC/airflow is a very difficult comparison. This is why they will take completely different set ups. Double the CC's would need double the carb size as well, if things were proportional, does anyone have any 84mm throttle bodies. Erik |
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| Rick_Eberle |
Apr 9 2006, 11:46 PM
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#48
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Member Group: Members Posts: 390 Joined: 14-January 04 From: Geelong, Australia Member No.: 1,558 |
If they did, I bet the type 1 guys would buy 'em! (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) |
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| Rick_Eberle |
Apr 10 2006, 04:02 AM
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#49
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Member Group: Members Posts: 390 Joined: 14-January 04 From: Geelong, Australia Member No.: 1,558 |
Hang on a minute, that would be true if the RPMs were the same, but at half RPMs, the size would be the same (assuming of course that the state of tune was similar, which maybe Jake could do, but not me). Also, an 84mm tb is four times the size of a 42mm. Double the size would be around 59.5mm. It's the intake area that matters, isn't it? |
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