Well I've been on G35driver for awhile now. Hydrazine seems to be going about this spacer job the right way. I just hope he doesn't release this thing to the general public before all of the bugs are worked out. There are a couple of things I'd like to point out...

1. Crawford V5 is almost a thing of the past. It would be nice to see how the new V? (maybe V-Cast) compares to this spacer. I don't consider this to be a "bug", just something that EVERYONE is interested in.

2. The spacer induces an alignment issue (due to the angle or wedge of the spacer). If it raises the top/front portion of the plenum, the through holes in the plenum are not 180-degrees, or co-axial, with the tapped holes in the lower manifold. So... when you go to tighten the socket head cap screws back into the plenum, the clamping force of the head of the steel set screw is putting uneven loads on the threads in the aluminum manifold and apparently causing the threads to gull or "strip". This is probably why E_K had issues with his threads stripping. An easy fix for this would be to provide wedged shims (or angled washers) to go under the heads of the longer screws that should be provided with the spacer if/when it is ever sold.

3. With the spacer you now have 2 interfaces instead of one like the stock plenum. I'd hope that hydrazine would include 2 new gaskets with his mod since there are now 2 interfaces.

Just some things to consider.

 

I fixed the stripped threads today by running bolts from the bottom of the lower plenum. The bolts also act as guide posts for the spacer and gaskets.

 

what bolts are those i might have to do that for when i get my 3/8" spacer...oh and there will be before after dyno runs

 

so my question is going to be, can you use this spacer on a Z with a crawford plenum?

will the hood close?

how much, and will it be available?

I thought I remembered Doug saying they tried all sorts of stuff with the lower plenum and didn't think the gains were worth the effort

 

I have the same question as sentry65 because I think there might be hood rubbing issues on a Z. May be a great solution for the G35 though!!

 

I doubt you'll be able to use both. Price is posted on one of the last posts on the first page. He doesn't know when it will be available, Hydrazine on 350zmotoring is the one getting these made. This doesn't deal with the lower plenum, this is basically raising the plenum just like Crawford does, just in a different way.

 

The bolts are M6 (meaning metric 1 mm thread with a diameter of 6 mm). I had to buy some M6*90mm bolts for the two center posts on the Crawford. Depending on the spacer you use, the length will have to vary accordingly.

I think Hydrazine is gearing the 1/4" spacer for 350z's. I know he's working on a solution for strut bar clearance.

 

thanks

 

E K, this is an awesome post. Your plenums are beautiful. Now, the bad news.

Aerodynamically speaking, a perfectly smooth surface does not move air as well as a slightly rough surface in small areas. When I say rough, I mean smooth, but like sanded with 200 grit or something.

This is why the intake port of a port and polish job is not shiny and why valves get "swirl" polishes.

The actual aero rule is that the rough surface has a turbulent, more energized boundary layer for higher velocity flows. (More velocity = more torque and torque x RPM = HP)

 

I totally agree with you. The actual intake tracts are sanded to approx 320 grit fineness. Infiniti even advertises polishing of the intake:

"Intake system: High-flow tuned induction system with micropolished tract and ports"

Definitely beyond the fuel injectors you'll want some degree of roughness. The smoothest and shiniest polish work I did was on the outside of the Crawford plenum.

If I ever have a chance to polish the exhaust side of the engine, it's time for super mirror shine.

 

curous if the strut bar fits over a spacer'ed plenum. if this does end up hitting the markets at under 200 dollars ill be in.

 

2. The spacer induces an alignment issue (due to the angle or wedge of the spacer). If it raises the top/front portion of the plenum, the through holes in the plenum are not 180-degrees, or co-axial, with the tapped holes in the lower manifold. So... when you go to tighten the socket head cap screws back into the plenum, the clamping force of the head of the steel set screw is putting uneven loads on the threads in the aluminum manifold and apparently causing the threads to gull or "strip". [/B][/QUOTE]

Hmmm...I might be missing something. The Hydrazine spacers that I saw (in the pics) were not wedge-shaped. They were the same thickness all around. This would mean NO problem with the uneven clamping force of the plenum bolts on the perimeter. Correct me if I'm wrong.

 

Living here in CA, I want it to look stock under the hood so this works a bit better for me than the Crawford plenum.

I ordered this from Hydrazine and he said "Everything you need for the install is in the kit. Gaskets, bolts, big spacers, little spacers and strut bar spacers. It's got everything."

From reading his information on the 350zmot*****.com board, he sounds like a straight up guy who knows what he is doing. When it shows up, I post some pics of whats included.

Also, it is under 200 just by a hair.

Chris

 

If the two holes are co-axial when they lay flat on top of each other... and you lift one side up by 1/2" but the other side is almost flat... basic trig tells you that the holes are at the same angle now as the angle you ended up raising the plenum... thus the holes are not aligned.

 

neff,

"both" sides ARE raised the same amount.

I don't believe it's wedge shaped.

I've seen AAM's & it's wedge shaped but not Hydrazines.

It's an even "lift" all the way around.

The very top of the plenum is angled.

But the portion where the bolts attach is flat all the way around.

D'oh

 

Gotcha'. I thought I recalled seeing a side view photo of the plenum spacer that made it look wedge shaped. Maybe I'm mistaken...

(like that would be a first )

 

Yes, what baileyrx said above. The spacer is the same thickness all around and not wedge shaped. (I thought it was a wedge at first also, but Hydrazine corrected me on that one.)

 

How did you order the item? Did you just pm or email him? Let me know, I'm very interested.

 

I have a few questions, and alot of concerns.

Where is the stock dyno first of all? Without the stock dyno I can not tell if it is actually any better then it was stock.

What is going on between 5900-6100rpms on the blue runs where there is the noticable dip. Is it lift throttle perhaps, missfire, or what? I have never seen a dyno look like that.

The AAM spacer has a much better dyno graph one that I will say is believable. With yours something is very fishy. Notice on the AAM dyno there is no dip; unlike your blue runs.

https://my350z.com/forum/showthread....hreadid=107875

How many runs total? Did you ever reinstall the Crawford V5 to see if the power decreases again?

There is a point where more space in the plenum is not going to help any more then before. With the Crawford plenum the restrictions have already been removed by lifting the front of the plenum. I don't see how you can really get anymore power; at a point just increasing the volume of air that is in the plenum is not going to make a difference.

Also I have major concerns about the fact that you stripped out threads. Even though you stated that you fixed the problem, I still think it is a major concern when using the stock mounting equipment. Your fix at best is probably temporary. If the threads are stripping you are using to big of a spacer for the stock mounting equipment, and then you have to find new bolts that can handle the torque load.

I'm really skeptical of this product mostly because of the dyno chart; something just seems out of place or "fishy" for lack of a better term.

Also I am having a really hard time believing the power numbers. Especially considered how low you dyno'd stock to sinple bolt-ons making that much power.

Your disclaimer personally worried me; most of the time I read things about new parts people don't have long disclaimers to try to prove to people they are telling the truth.

 

Jamesz, your concerns are very valid. I'll try and address your comments.

A stock (meaning stock plenum only), would have been a good next run, but again the stripped threads and my time constraints cut our dyno session short.

As for the dip in 5900-6100, I can't explain it. I saw the shop owner warm the coolant up to the same temp before every run, then run each run the same way. The dynapack may be measuring power differently than a dynojet. The dyno we use gives us the raw numbers in Excel format. I can email you the Excel file if you want. All I did was plot the data, I can't influence it. If I could influence dyno numbers psychically, I wouldn't have got low numbers with my dynojet runs.

There were 4 runs with the Crawford, with an ECU reset after the 2nd run. There were 3 runs with the spacer.

I am now running with the Crawford AND the spacer, because I think both are good products. Doing a dyno on that config would be next, but I'm out of $$$.

You're right, there is a point where adding more volume to the plenum chamber will no longer help, and will likely hurt performance.

I do believe that my current solution for the stripped threads is very good, since the interface is now steel on steel. I don't think it'll be a good solution for the general public, since it involves more work of removing the lower plenum.

The absolute numbers are not important, since the first dynoes were on a different machine. The dynapack will give out higher numbers.

I gave the disclaimer because I've seen too many times on this forum dynos being shot down with various accusations. The only deal I had with Hydrazine was a free spacer in exchange for dyno testing it on my car, regardless of the results.

Anyway, it's up to everyone to spend their money wisely. If you don't believe me when I say that I don't see a dime of profits from sales of the spacer, then I'm not sure how to prove it. That's the problem with the Internet, anyone can make claims and it's hard to disprove them.