Well, you guys (and gals) have been very helpful in finding info for more "advanced" situations, so I thought I would pick your minds on this one. I run an NA DSM (420a engine) that I've done a bit with. I'm currently fabbing up ITB's for the race car. I first did 42mm's;


Which were obviously too small for the higher rpm of a race car, but are actually ideal for our street cars.

So I am fabbing up some 52mm TB's (our stock sized TB's with the narrow channel in the TB throat taken out);



I can't seem to find a good distributor of velocity stacks. Having been in the "old school" carburated world for many years, I know that there has got to be an extensive (and inexpensive, lol) supplier somewhere. I mean they are basically formed plastic trumpets.

So, short question would be, could somebody help me with finding a supplier for 52mm velocity stacks for the ITB's?

Thanks in advance,

MB

 

Jenvey has a good selection of airhorns, in various sizes. I've used their products with good success in the past. You can order directly from them, or find a dealer near you.

Your other options would be to find an OEM carburetor or ITB of similar size (large motorcycle ?) and use the velocity stack off of that application.

Good luck on your search.

 

Second one from the top, several sized are available.

http://www.advancedstreetperformance.com/intake.php

 

http://www.velocitystacksonline.com/

 

Well, I'll be darned. Great Britian, Australia, one would think that we had a bit more access in the US. The Australia one, a buddy of mine did order from them and said it took 4 weeks to get here.

I know all about pay to play, but I would have hoped that we could get closer to a C note for a set. Meh, I guess I'm relagated to hitting up the V-dub off roaders for some Empi cones and cutting them down.

Oh yeah, on that OEM bike thing. The 42mm TB's were, I believe, off a Gixer 1000. So far I haven't been able to find any other bike that would have the 52mm velocity stacks. Too big it seems.

Well, I appreciate the help anyway.

MB

 

The Jenvey products are the closest shape and design you will make the most torque with.

 

The GSXR velocity stacks that I have measure 54mm I.D. @ the throttle body opening and 60mm+ I.D. at the VS opening......

 

Really? Well, that's promising. I was told when I picked these up that they were off a GSXR. Hmm, maybe I can find something then.

Thanks,

MB

 

Just filling in the dots on this thread.

Haven't found any info on those sizes for a GSXR. The sizes I've seen listed (depending on engine size) are 38mm, 40mm, 42mm (with a possible GSXR1300 at 46mm). Here's a couple of threads off here, referencing said information;

https://honda-tech.com/forums/showth...highlight=gsxr
https://honda-tech.com/forums/showth...highlight=gsxr

As for my 52mm set-up, I said screw it and decided to just spin my own. Can't believe there is not a relatively inexpensive option out there for velocity stacks (IMO, shouldn't be paying more than $100 for a set of stacks). Though I will be using Jenvey's equations to come up with the size.

Thanks for the help guys,

MB

 

Nice to see that you were able to get something that will work for you. I would love to have the ability to spin a set myself....good luck with your setup

I got those measurements myself....Here are a set of OEM 2001 (or older) GSX-R1000 rubber velocity stacks that came on an air box that I bought from an ebay listing.



I.D. of lip that slips over throttles,


O.D. of Vstack trumpet/opening


No image but they are 50mm high/deep. Measured from the lip of the throttle body to the lip of Vstack. and the ID at the throttle lip is 50-52mm. They are rubber so they stretch a little bit...lol

So if the O.D of your throttles is anywhere around 54-50mm (give or take a few mm) these should fit, The ones I have came with a screw type O-ring clamp that has 10mm of adjustment.

Posted this info just in case anyone else might be looking

 

Sweet info. Great to know for future searchers.

Thought I would post up, just to come full circle on the thread. My buddy spun these out for me (nothing like "free to me" for a cost savings);



30mm tall, with 52mm at the opening. 6 degree incline to the edge of the "circle"

A little messy installed, but should be effective;

 

when doing itbs....im guessing the butterfly size makes a bigger difference than the v-stack right....will there be gain from a 43mm butterfly with a 52mm stack vs a 48mm stack for example...?

 

http://www.velocity-of-sound.com/vel...ity_stacks.htm

 

Basically, you are matching the throttle body "butterfly" size to your engine set-up (diameter size would depend on your set-up, as well as, your goals). In that sense the butterfly size is obviously more important than the velocity stack. Once you find the right size TB for your set-up (and goals), the correct size velocity stack will help add power.

As West Werks showed you in his link, there are formula's to help you come up with an approxmate size and length velocity stack that will work best with your set-up.

This is meant as a very generic explanation of the relationship between the velocity stacks and the throttle body size. In a nutshell, set your TB and then properly match up a velocity stack for added power.

MB