Ok, so here is a question from the mod noobie! What size space should I use for my car? I have noticed several different sizes. It seems, from my short time looking into it, that 5/16" is the most popular. I have, however, seen as big as 5/8". Is more, in this case, better? Let me know what you think.
Thanks!

 

If you plan on using your engine cover then I think the largest you can go with is the 5/16". If you plan on buying a front strut bar you also have to be careful with what you get since some of them wont clear the taller spacers.

 

I have a stillen front strut bar, so it's a 5/16 for me....the bigger is somewhat better but the HP is maybe like 3-4 different....

 

only 2 i know of are the 5/16 and 1/2...the 1/2 is more for the FI group..5/16 is more commpn and logical for an NA motor..i recommend getting one form the marketplace..theyre cheaper

 

i got the motordyne 5/16 copper spacer from Ben(buckeyeG)
after the install i felt more better response over 3-4rpm,
definetly the best bang for the buck mod

 

I have a 5/16th spacer with my Vortech SC w/2.87 pully and im about 450rwhp with 100 octane.

 

If you look at Motordyne's website, they've got some nice dyno charts showing the advantages of various sizes of spacers. In a nutshell, the 1/2" and 5/8" will give you more HP at the top end at the expense of power down low whereas the 5/16" seems to have a much more useful power curve for the average non-FI setup. There are also 3/8" out there that are probably similar in performance to the 5/16", but I'd recommend getting a Motordyne and they only have 5/16" and 1/2". You really feel it kick in around 3500 RPMS. That and a Z-Tube really changes the intake note. Gives it a nice, deep growl. It's the single best NA mod you can do to our cars.

PM Tony or Rick at Riverside Infiniti (members here) and they'll get you a great price. I got the MD 5/16 Copper ISO unit for $240 shipped last December. It's been awesome. I installed it the weekend after Christmas, and when I started it was like 38 and raining outside. When I finished about 3-4 hours later (I was also installing a grounding kit), the weather had changed slightly. And by slightly I mean a blizzard had moved in and I had 8-10 inches of snow on the ground. Good times.