Brandon@Forged

Could just be thicker at the top of the oem plenum than at the bottom.

JAMESZ

I guess you haven't looked to carefully at a stock plenum.

Brandon@Forged

Guess not, regardless, that spacer is making gains with the plenum still sloped down, I imagine if they make it taller it will gain more (and be near even height with Crawford and Kinetix).

Z1 Performance

iTrader: (564)

when you raise total plenum volume, the issue with the front cylinders is VASTLY improved. However this is not the only shortcomings of the plenum. Anyone who has used a manomometer on their plenum can tell you this. The issue of overall plenum volume is the biggest contributing factor to the front cylinder issue - but there are lots of other areas of concern inside the upper plenum (and some in the middle planeum "tray" as well, that are all part of the equation. Frankly, none of the plenums or spacers on the market address all of the issues that are present. I have access to parts and services that the vast majority of the people on this board do not, and the way I looked at the scenario when approaching the build of my own heads was this:

1. The Crawford plenum (which I considered) - does a good job at addressing the major issue (plenum volume) in a clean, unobtrusive form. A bolt on solution. Having not had one on the bench yet to play with, I don't know how it deals with the other shortcomings we have discovered in the plenum area. I know one area that it does not address at all (not really a big deal to solve though it takes alot of playing around and not something an individual customer really could do successfully without access to some sophisticated equipment). But as I said, it's a bolt on solution that addresses the most serious of the stock plenum's shortcomings, that being volume of the front relative to the rear. It's an even easier solution for people now that they have a cast version released - hats off to them for that as its not an easy thing to have done.

2. The Spacer - more for the guy who is going to play IMHO with his own setup. The plenum also addresses the issue of total volume, and does a reasonably good job at addressing it. It does not address any of the other shortfalls of the stock plenum design, though it affords the user a quick and easy fix for the major one (again plenum volume), and leaves the other issues up to the user to discover and address.

My own choice was #2, specifically because it is specifically what my machinist asked me for in our last conversation on Wednesday. He already is aware of the Crawford plenum, and it would have been a terrific solution for me, but would have required me to ditch my strut brace, which I did not want, nor could not do. I am reasonably sure the spacer will still allow for my brace to clear, and given that it's what my machinist asked me for, it's what I went with.

I suspect both products will see an increase, not a decrease in sales, because they both address the most serious violation of airflow in the stock design from slightly different angles. Assuming the Crawford addresses at least some of the other areas of concern in the stock plenum (I suspect it is as there is some porting that they do I believe), it is more of a bolt on solution. However, by utilizing the spacer, the end user essentially gets themself the chance to address the most serious issue in a piece that is a bit more cost effective. I personally think it is great there are choices, and as mentioned, I suspect both items will serve a purpose for people and both products will see a net gain in sales, not a "victory" by one vs the other

Adam

screaminz

Nice write-up Adam...
Screaminz

Z1 Performance

iTrader: (564)

sorry for any gramatical errors and for the amt of times I used "address" Should have proof read it a bit better

copba1t

iTrader: (2)

If you are trying to suggest that a bunch of gaskets (with jagged edges on the inside and almost impossible to control the height precisely) is the same thing as a properly machined and polished spacer that fits flush on both sides then I just have to laugh at that. I'm not even an engineer and think the idea is just ridiculous.

I think the whole gasket concoction is just a way to mock and discredit the work that your competitors are doing to prevent loss of business. I think you should know that this strategy will backfire and have the opposite effect.

Oh, and also, that excuse "oh it's just Chris" doesn't quite fly. If someone is posting with your company logo in their sig then they basically represent the company, especially if they are including names of co-workers in their posts. If you need to make excuses for someone in your company then maybe you should re-consider their role and why they are opening their mouth to begin with, as it does impact your image as a whole more than you might think.

These are just some of my observations as someone who is just starting to look at intake mods, and for the record I am still considering all options, including products from Crawford.

SirZaLot

iTrader: (1)

I think it's because of.....
1) It works about the same as all others (so it seems)
2) A lot cheaper

I don't think it should be a surprise that ppl are charging for them.

randyshemin@comcast.

copba1t,

After reading your post, I felt obligated to reply to try to set the record straight on this subject.

I was at Doug's shop yesterday when he suggested we try the stacked gaskets. I am the one who took the pictures that Chris posted.


Doug knew that it would work, because as part of the R&D for the cast plenum, and to determine the exact, optimum height for the plenum and how thick to make the flange that attaches to the lower plenum, he stacked gaskets to make sure there were no clearance issues, and to make sure the other criteria were met as well. The final design, whixch is now at the manufacturer, was detemined solely by stacking gaskets on the prototype castings as shown in the pictures.

And yes, you can stack the gaskets as shown, and due to the material Nissan used, there is absolutely no leaking once all the bolts are tightened down. It simply does work, and we've seen it time and again! In fact Doug put the spacers we photographed on his car yesterday to prove to another customer who was at the shop and got in on the discussion that it does work, and still has them on there this weekend.

In summary, stacking the gaskets will give you the exact same result as the spacer (which is beautifully done), but by using the stock plenum, as so eloquently stated above, you still have the issue of the slope at the front of the plenum, which the Crawford and yes, even the Kinetix product so ably address.

As for Chris, we apologize for the way he comes across, but as James said, once you get to know him, you really can't help but like him. I consider myself a convert, as he really used to get on my last nerve too when I first met him 3 years ago, mainly due to our age difference I think (I'm 48, he's in his mid-20s) and he can at times be way over-the-top. But now I consider him a good friend, but still wish at times we could do a better job of reining him in. We call him the INDIVIDUAL, and we apologize for his past AND future offenses.

One more thing...
Has it been determined whether the spacer can be used with the stock 350Z strut bar? We know the Crawford cannot, and even the Kinetix is having issues on some cars. And is there any clearance issues with the hood on the 350Z? As for the G35, I understand there is more room under the hood and no strut bar to contend with.

copba1t

iTrader: (2)

I am not disputing if a stack of gaskets would leak or not, I doubt it would. I am talking about optimal airflow and potential drag created by having the jagged edges of each and every gasket all grouped together. Don't people go to the extent of even polishing the inside of their plenums to ensure optimal airflow?

So you are saying that the uneven edges of your gasket stack will have absolutely no impact on airflow, as compared to a flush-fitting spacer?

So far it seems like the smoke is really flowing here...

randyshemin@comcast.

Once the gaskets are in place and tightened down, they line up beautifully as they are all exactly the same shape: therefore they come together as one.

copba1t

iTrader: (2)

Yea, I think I understand. Some companies needs someone to do their dirty work (as in sending out someone to discredit the competition), then just try to pass it off as them being crazy and apologize for their supposedly innocent actions. Some people will see through that act though, because if you do not prevent those actions then that means you support them.

copba1t

iTrader: (2)

I just don't see how it's possible to line them up perfectly, for them to be as effective as a smooth polished surface...

randyshemin@comcast.

I see where that impression comes from, and I agree with part of what you say. However, if you read Chris' posts on other subjects on this forum, you will see a similar tone. He's been banned once already, and probably with good reason.

We're not defending him at all, or making excuses. As I said, I wish we could rein him in, but we've come to the realization it's just not possible.

uro279

Hey Coba1t,
I understand your skepticism, but tone down your cynicism so this can stay a informative thread as opposed to a flame war.

However, having said that, I don't like the fact how Chris did come on here and seem to bash it-very poor form. This may backfire on Crawford and hurt sales.

Anyways, there already is too much misinfo. on the boards. So lets wait for numbers and see how they compare to plenums.

See ya

Brandon@Forged

Although I agree with you some. I don't see how it's ok for member's to bash some products and not others, especially when one DOES show dyno's, the other doesn't. Regardless, there shouldn't be any ''bashing'', skepticism is normal, and companies SHOULD have to prove themselves, but sometimes they prove themselves and the member's are still skeptic. Member's should understand we aren't going to get a comparison of EVERY product available in a category (5 base dyno's, 5 after dyno's, on the same day, SAE and non corrected, on a bone stock car (Z or G), etc.).

Back on topic now.

TimeAttack

So are you now acknowledging that raising the stock plenum
with a spacer of some kind provides more air volume to the
cylinders, thus gaining some HP?

Basically, you agree that the theory behind the spacer is the
same as the theory behind the Crawford cast plenum, and
therefore, the two products would create approximately the
same results?

Zivman

iTrader: (19)

I think you said it right in you first line "gaining some HP"
I know the new crawford cast plenum also has a larger inlet, so it is more than just rasing it up. Either way you look at, you have a $29 gasket stack that is doing exactly what the $200 spacer does. Point was, you can buy the gaskets over the spacer or any aftermarket plenum, it's your choice.

I think chris was getting somewhat defensive because of the amount of R&D that crawford has done in regards to their products for the Z. He also stated that crawford looked into doing a spacer to raise the plenum, but found that modifying the plenum was a better solution. People can buy or not buy whatever they choose to, but I actually find it humorous to pay near $200 for an item the $29 worth of gaskets can duplicate. In saying that, I find it silly to spend 350 on a their new plenum + 150 for strut bar if that same stack of gaskets costing $29 does the same thing in terms of gains. All that being said, I am on the list for a new cast crawford plenum.

randyshemin@comcast.

The spacer does not address the basic shape of the stock plenum, as stated.

Theory and execution are two different things.

Doug had access to the VQ engine well in advance of the release of the 350Z, and with the help of a friend who builds race engines in the Southeast, they determined that the plenum shape was restricting the front cylinders. That's why the Crawford plenum, and the other one on the market raise the front edge to eliminate that restriction.

Doug tried spacers first, but they quickly realized that increased volume only PARTIALLY solved the problem. Therefore, the modified plenum was created, the gains were realized and documented, the rest is history.

The spacer may provide gains, but.......

There's a pic here showing the front edge of the stock versus crawford plenum:
http://www.crawfordz.com/pics/castpl...tockplenum.jpg

copba1t

iTrader: (2)

If anyone thinks that a stack of gaskets is a solid long term solution to anything then I seriously question their judgement and any other information they might contribute. I wouldnt put those gaskets on my car if they were given to me for FREE, the whole idea is just laughable IMO.