Ya, im curious about A/F as well. Also curious in the diff. in performance for a 1/4, 3/8 etc. what material is it made from, plastic?? how durable is that?? I mean it is almost $200 for the spacer...and if in fact crawford is coming out w/ a new plenum as neffster mentioned...which allows you to keep the core and is much cheaper...id ike to know how much cheaper...$200 just seems a lil high for a piece of plastic....i dont doubt the product...just a tiiiiny bit skeptical...im gonna have to wait on this one...until i get some more feedback.

 

Excellent dyno test. It looks like I'll be keeping an eye on these new spacers. I'm curious to how well they'll seal. If they're metal, it should seal quite well.

 

The spacer I'm using now is aluminum. I'm using a gasket below and above it, so the seal is pretty good.

My A/F was about 14 at peak using this dyno. I don't think the A/F reading with this method directly corresponds to A/F with dynojet readings, so I can't make any further conclusions on this.

I don't have the data in front of me now, but I can plot the A/F tomorrow.

 

How about using the plenum and the spacer? 10Hp is huge and I would guess very unexpected. Hopefully these gains can be confirmed.

 

Yes... Pricing and Where can we Order them from...?

 

Hydrazine, time for a patient. I think Nissan would be interested in owning a patient that could add ~$50/car and raise their hp by 10-12 at the crank...

 

Very nice, Hydrazine.

It looks like you've got a hot product on your hands! I'm sure the Crawford Z guys will be happy to see this. Especially when they are preparing to roll out their new cast aluminum plenum, which would probably dyno the same as the V5 you tested.

So what's the pricing on this spacer? It's made of aluminum? You use 2 stock gaskets to seal, one on top of the spacer and one below the spacer? I'm assuming you need longer, aftermarket bolts to secure it?

Side note: How much performance is really gained by having 5hp more than the Crawford V5 plenum at such a high RPM (right before redline)? Would this even translate to a faster 1/4 mile time?

 

Would the spacer plus cv5 plenum fit underneath the hood of a G?

 

Neff,

The patent process has been initiated. I'm doing a couple things differently on this project that I want to keep protected.

If we assume the CV5 produces 10 HP then the 1/4" spacers are looking mighty good. But just to be conservative I would say spacer results will pobably be more in 6-10 HP range, the yeild also may be affected by the other mods installed. The stock plenum with spacer may have a resonant synergy with Ztubes and velocity stacks like on E_K's Popcharger where it sings at just the right frequency and in phase with the intake runners. One thing different about the spacer from the CV5 or Kinetix is that it uses a stock plenum. As you know, the stock plenum is that its very rigid and solid. No flex or movement at all while under load. If acoustic tuning is part of the equation, solid enclosures tend to help.

A 3/4" spacer on my car with a "dirty stock air box" produced 11HP. (I should try it again with my clean Stillen CAI and Ztube.)

Based on the recent tests E_K and I did, I won't be too quick to say that bigger is necessarily better. Power may be (probably is) just as dependant upon plenum helmholtz tuning frequency as it is on flow pressure drop.

I'll get A/F plotted up.

 

Nevermind.

 

Is the factory plenum as smooth inside as the CV5 or other aftermarket ones? Like a ported/polished head the air would be less restricted running into a smoother plenum rather than the factory one with a spacer, thus making a bit more hp. For all I know the factory plenum is just as smooth inside as the others. Just another thought.

 

Subscribing to this thread......very interesting..

 

Do I hear a group buy?

 

None of them are what I would consider smooth. The factory plenum has the casting marks, and the Crawford V5 has the welds. But I don't think there's much benefit to polishing the inside of the upper plenum, since the air is turbulent there anyway.

With that being said, I still polished the underside of my Crawford V5 as best as I could, cause that's the kind of OCD polishin' person I am. (pic taken without flash)


The new Crawford cast plenum should be an easy polish job.