Hey guys, i did some before and after runs between the two different spacers. These two dynos were done one after the other so the variables didnot change. I did 3 pulls with the blox 5/8 spacer, and then 3 pulls with the motordyne 5/16 spacer. I changed the spacers while my car was on the dyno so that the results would be as accurate as possible.
The motordyne spacer gained more torque and Hp at all rpm ranges. In the midrange, around 4k, the MD spacer gained about 8lbs of torque over the blox spacer, and around 5000 rpm, the md spacer gained around 9 hp.
I was really amazed to see that the md spacer had better gains in the higher rpm as well. Blox was supposed to be most beneficial in the higher rpms, but the md beat the blox in that area as well.
I gained around 2hp, and 4lbs of torque in terms of peak power.
Overall this was well worth doing a before and after dyno. The midrange power is definetly felt by my butt and dynapack dyno. This was my before/ after dyno, which was performed at Church Automotive, Socal.
I have a 04 g35 sedan. Pics of dyno are attached as well. these are pics taken by my iphone so they are not that clear. i will scan it tommorow, and have better pics tommorow. guys if you pick anyhting out that i didnot mention, please let me know. thanks.

The blue line is a dyno with the blox, and the green/red is with the md spacer on.

 

Thanks for the tests. Many of us are aware that bigger (thicker) is not necessarily better.

 

but that's not what she said?

 

^^^ Haha you beat me to it.

 

list of mods?

 

stillen gen2, engine damper, kinetix cats, dc headers, jwt popcharger, ztube, md spacer, ur crank pulley

 

hmm 270hp out of that not bad

 

Anyone care to explain why this is the case? Is it related to different intake resonance when 5/16 spacer is used vs. 5/8? You'd think the larger spacer would provide better flow although this dyno suggests otherwise.

 

You got it Ziggyrama.

It can only be due to resonance. In 2004 when Motordyne was doing R&D on spacer size Vs HP, a range of spacer sizes were tested. Everything from 1/8", 1/4", 3/8", 1/2" and 3/4".
5/16" was eventually settled upon as having the best overall results.

What was interesting to see from the testing is that not only the 5/16" had a better overall response than 1/2" spacer, the 3/4" spacer lost power everywhere compared to the 1/2" spacer.

Not only 3/4" was larger than optimum for power, it would contact the hood when installed on a 350Z.

There are only two plastic spacer manufacturers that use a 5/8" tall spacer. My guess is they simply developed the biggest spacer they could possibly fit under the hood of a 350Z before putting it into production.

This same resonance effect was also demonstrated in the Nissan Sport Magazine comparison.

 

I wonder how the difference in spacer size would effect an FI engine. Tony , have you played with that side of the house ?

 

I'm curious if any better performance could have been achieved with a non-nominal thickness, i.e. something that is not a regular inch size. I am thinking maybe 9 mm (between 5/16 and 3/8). But even if there was an improvement, it's probably just not economical because the fractional inch sizes are probably the readily available off the shelf material, and therefore more cost effective.

Anyway, I'm still really happy with my 5/16 spacer + MREV2.

 

EDIT: Interesting read here.
https://my350z.com/forum/intake-exha...k2-spacer.html

 

Great thread, I still promote my MD 5/16 spacer to any Z owners I come into contact with. Its not only a difference you can really feel, but they also have excellent customer service.

 

Yup, after this dyno i have no second thoughts of recommending people to get MD spacers

 

I'd imagine the OEM manifold is resonance tuned, albeit with a slight shortcoming as far as flow distribution to the front-most cylinders. The smaller spacer possibly helps correct the flow distribution problem, without significantly altering the OEM resonance tuning.

TK

 

 

I haven't dynod it myself so I don't have any plots to show. There are many people using them with FI but very few post dynos of it. They are very rare.

This is one FI reference.
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https://my350z.com/forum/forced-indu...-19-46whp.html

There was one other that I can remember posted a while back by RandysG. He had a Vortec and made approximately 17 HP.

 

most of the time the spacers are just 'part of the build' and not individually tested on the engine it seems. only big dollar components seem to be singled out by the FI crowd... the SSV got the treatment as did the Cosworth.

fwiw, I have the 1/2 inch spacer edit: MOTORDYNE of course

 

I had just recently tossed my Kinetix v+ full plenum for MD 5/16th spacer. Even thought the kinetix sounded meaner and louder during start up, the power difference was very apparent. From my butt dyno, the car had a much better torque response from the MD spacer than the Kinetix v+ plenum. Less lag, and much stronger pull. I'm glad i made the switch, and i would highly recommend teh 5/16th spacer to all of the Z owners....

 

I install MD 5/16 spacer and waited about 2 weeks to do a dyno. I ended up losing about 6 lb/ft of torque and 1-2 hp

Anyone have any clue why does this happened? Is it necessary to reset the ecu (disconnect the battery for 24 hrs)?