Ok, so as some of you know, I just got my '02 ZR2 last week...I'm finding all kinds of neat stuff (like what I think is a volume **** for the subwoofer output on the Audison amp that was in the truck...).

Anyway, I put gas in it today, and as usual while doing this, checked the oil. Whilie I was poking around under there I noticed what appears to be a throttle body spacer...it's about an inch tall, mounted between the upper intake manifold & throttle body, and it's blue.

What exactly is the benefit of these? Back when I had my mustang, the phenolic spacers that went between the upper & lower intake manifolds were reportedly good for keeping the upper intake cooler...is this the same deal? Does the fact that this one is blue mean anything specific (particular brand/size/whatever)?

Also, it does have the K&N FIPK & a catback exhaust. Is there anything else I should be poking around for (like typical mods that 'go with' the ones I've found so far)?

Should there be some sort of modified ECU flash I should make sure I'm running with these mods?

What about octane? Manual says 87, but is there anything that would make me want to run higher (for example - is advanced timing a likely 'mod', given what I know is done to the truck)?

I know this is all a guessing game, but you guys know what people do to these trucks...guess I'm looking for a head start on the poking & prodding I'm going to have to do. Any and all comments/suggestions are very appreciated.

 

Throttle body spacers are supposed to shift the torque curve lower in the RPM band, however, on pushrod engines that already have a low torque peak, they mostly do nothing. On older carbuerated engines, they served as a spacer to keep heat away from the carb as well as additional volume for better mixing of the air & fuel.

As for the octane of the fuel... Well, unless you have done something that has produced KR (knock retard) of the timing, then you don't need a higher octane. Things that would require higher octane are increasing the timing (custom ECU required), increasing the compression ratio, or moving to forced induction (turbo, supercharger, or centrifugal supercharger).

*EDIT* - Just thought of some more information for you. As far as the octane of the fuel is concerned, the higher the octane, the slower the burn, hence its resistance to knock (predetonation). You want to be using the lowest octane that you can that will result in zero KR. Using anything higher than this will be of no additional benefit.

 

Interesting. Why do so many people have them?

Thanks...I know all about spark knock & what causes it, and how it relates to octane. What I was asking (and the reason I mentioned psychics in the subject) was whether there are some other mods that are commonly done along with what I have DEFINITELY found that would require higher octane (among a host of other questions).

Let me give you an example: when I had my 5.0, very typical mod 'sets' were CAI, larger throttle body, aftermarket intake, catback exhaust, etc...and along with these, people ALWAYS advanced the timing (free HP), thus creating the need for higher octane fuel.

So if an unfamilar person came to me and said 'hey - I just bought a 5.0, and it has a CAI, 70mm tb and an Edelbrock performer intake...what else do you think was done?', I could, with some confidence, say that the timing was most likely advanced (among other things), and therefore higher octane fuel would be a good idea, regardless of the manual calling for 87.

Fastforward from 1989 (my 5.0) to 2000 (my V6 Mustang) - same idea, but now computerized - I flashed the EPROM with a custom program that was written specific to my mods, resulting in advanced timing (among other things), and requiring the use of 93 octane, regardless of the manual calling for 87.

Now, here I am in Blazer land, with just enough knowledge to be dangerous, and I'm asking if there are similar mod 'sets', given what I know to be true about the truck. Is there a chip or piggyback unit (like the K&N powercommander I had for my bike) that I should be looking for, and that would creat the need for higher octane?

 

Like you said the only reason for higher octane in a blazer is if the computer was flashed to require it... and there is no way to know unless you were told it was done or you did it your self...or if you took it to the dealer to have a computer upgrade and they tell you that there is an unauthorized program in there and they replaced to to update your computer to factory specs for a Service Bulletin or Recall....

Have you checked the TB Blade to see if the diffuser has been removed??? If not you could do this a couple of ways...I have personaly researche the fact that a Cadillac Northstar TB plate will bolt directly into the blazer TB and it has not diffuser...and it also does not have the small hole in the plate to allow for the pressure difference when the blade is closed....or you could try to remove the diffuser by taking it out - drilling the rivots holding in the diffuser and removing it - then solder the holes closed so that idle is not affected...