Crawford cast plenum vs. Motordyne spacer
#17
#18
I have the spacer and can definitely feel the difference in power throughourt the powerband. Throttle response is much better as well. There is a video two coups doing two runs against each other. One coupe is a stock 056MT and the other was a stock 04 5AT (other than the 19" aftermarket wheels and a subwoofer)which was later modded wih the spacer. In the first run the 05 edged out the 04 pulling ahead in 3rd gear. In the 2nd run the 04 edged out the 05 throughout the powerband in each gear. Good evidence that the spacer works and I would expect the plennum mods to likewise work the same.
#21
Originally Posted by truplay8
stupid question- Can you get both??
#23
Originally Posted by glennp_1999
That would be overkill unnecessary if you have one or the other. It will do the same thing except the plenum will produce about 1-3 hp more than the spacer. The plenum however is a much more expensive setup than the spacer. If you go with CP you have to core your original plenum otherwise you pay even more. Kinetix is a bit cheaper but you have to be careful installing it over tighten it and it may crack.
1. There is NO CORE EXCHANGE necessary for any plenum mod any more. For the last 5-6 months Doug has ONLY sold cast plenums. This allows you to keep your stock plenum since the new Crawford design is made the EXACT SAME WAY your stock intake manifold cover is made. It's an aluminum casting.
2. Any dyno that shows one mod gaining 1-3rwhp over another mod is pointless. Too many variables to argue over, so the safe bet is to say that both of these mods BY THEMSELVES are close to equivalent.
Also, the plenum BY ITSELF is not a "great mod" (neither is just the plenum spacer or just the h/f cats), but when you combine the plenum and the h/f cats you get a "great mod". There is more than one restricion in the stock intake/exhaust design and unless you remove a restriction on each side of the intake/exhaust equation, you're not going to see/feel a big gain if you stay NA. For those of you that tried a plenum or a spacer and didn't feel much, I STRONGLY recommend changing the stock cats to h/f's and giving us your "new opinion" of the two mods combined.
#24
Well there you go no more core exchange so it got a little better. So how much is Crawford asking for in price now? You are right aguing over 1-3 hp gain is pointless that's why I went with the spacer. See when I bought my spacer the CF was about 400 w/ core and 700 w/o something like that I forgot already. The spacer was less than two hundred bucks and for the same kind of gain so no argument there. The H/F cats alone is a good mod get rid of the Y pipe and go true dual is even better.
#26
The only dyno that I know of that compared the spacer to the Crawford, with the car never being unhooked from the dyno going from one setup to another was the one I did with Hydrazine back in January. The car was warmed up to the same coolant temp each time, the car had the same tank of gas. All the runs were done within 1.5 hours of each other, with the same dyno operator. The ambient temps ranged from 68-72, the humidity pretty much constant at 54%.
We did about 6-8 runs with the Crawford, and 4 runs with the spacer (1/4").
On average, the spacer had 5 HP more at redline. I say on average, because too many people/companies just tell you the worst run with one setup, and overlay the best run with another setup on top of that.
Last month I redynoed on the same machine with the Crawford AND 1/4" spacer. Keep in mind that it was warmer this time around. The combo was about 1-2 HP better than the Crawford alone, but 3-4 worse than the spacer.
I've still kept my Crawford though.
(numbers are on the dynapack, a stock 350z 6MT gets about 255 WHP).
We did about 6-8 runs with the Crawford, and 4 runs with the spacer (1/4").
On average, the spacer had 5 HP more at redline. I say on average, because too many people/companies just tell you the worst run with one setup, and overlay the best run with another setup on top of that.
Last month I redynoed on the same machine with the Crawford AND 1/4" spacer. Keep in mind that it was warmer this time around. The combo was about 1-2 HP better than the Crawford alone, but 3-4 worse than the spacer.
I've still kept my Crawford though.
(numbers are on the dynapack, a stock 350z 6MT gets about 255 WHP).
#27
Originally Posted by neffster
I'd go with the Crawford Products ALL DAY LONG. It has been proven over and over that the Crawford Headers and Crawford Cats are the best (hands down) parts for our cars period.
Headers- 100% equal length primaries, 25" long, hand made, thick wall steel and powder coated. Best gains of any header available for our cars.
I say support Crawford and you won't be sorry!
Headers- 100% equal length primaries, 25" long, hand made, thick wall steel and powder coated. Best gains of any header available for our cars.
I say support Crawford and you won't be sorry!
Last edited by dentalstud; 08-16-2005 at 10:12 AM.
#29
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The spacer has to be one of the most dynoed mods on this board. When Motordyne first came out with them they were bombarded with "give me dyno results" requests and healthy skepticism. Rightly so. Motordyne dyno days as well as independent dyno contributions have shown proven gains time and again, at least as much as any upper plenum replacement for half the cost.
As for headers, maybe there are more dynos to be had on one of the 350Z sites but I've not seen a lot here (any?) where it was the single mod changed. Since you're talking some significant coin to purchase and install headers it'd be nice to see the same scrutiny applied to the header mods as the spacer. The spacer is a no-brainer IMO.
As for headers, maybe there are more dynos to be had on one of the 350Z sites but I've not seen a lot here (any?) where it was the single mod changed. Since you're talking some significant coin to purchase and install headers it'd be nice to see the same scrutiny applied to the header mods as the spacer. The spacer is a no-brainer IMO.