Plenum spacers?

[prophiseer]

lol, I got the idea from a few pro-stock vehicles I've seen in the shop, I noticed it first a coupla years ago on our '65 GTO that's always in the door; wood spacers between the manifold and carburators keep them cooler and help fight vapor lock - works quite nicely, if I might say so; and on top of all that, lord is it a cheap mod!!!

[IsaacHayes]

cheap and easy to machine! You could smear on a layer of jb weld and sand it true too to help sealing. Do you have to use thread locker because the wood eventually smashes?

[prophiseer]

Naw, all I did was put the gaskets up and tighten down an extra 5 ft/lbs on the UIM bolts. I don't forsee any real problem in the near future with the spacers starting to collapse . . . and if they do it's not all that hard to make new ones . . . I doubt they'll crack or anything, plywood is fairly resilant.

I used an extra set of UIM gaskets as a template, then cut the spacers out of te plywood, sanded all the edges nice and smooth, the hung them up and sprayed them with a few coats of water sealant, then a final coat of black paint (wood looks kind of odd beside aluminum!). Made sure they sat for a coupla days to ensure everything was dry-dry and bolted them in. Being sealed against moisture and exposed to the motors temps, they should never absord any type of moisture - which is the leading cause of wood-rot. No matter what, though, they were cheap!

[IsaacHayes]

You know for as easy as it would be to make those, I feel like making some myself! Heck if I had aluminum plate I'd cut it out myself too by hand. But I'd rather do the wood just for fun. I don't need no aluminum spacers. I wonder what's the max height you can raise the UIM before the hood clearance is a problem...

[bszopi]

You know for as easy as it would be to make those, I feel like making some myself! Heck if I had aluminum plate I'd cut it out myself too by hand. But I'd rather do the wood just for fun. I don't need no aluminum spacers. I wonder what's the max height you can raise the UIM before the hood clearance is a problem...

1"... been there.

[IsaacHayes]

Hmm 1" isn't going to gain you anything really. I guess a custom intake manifold is worth the work more than raising the plenum at least for changing the runners is concerned. For me I'll be shortening my runners with the 3500 plenum

[prophiseer]

yeah, I'm nowhere near an inch

At least sitting in a lane or at a red light waiting a few minutes (heck-o-lot longer when at a traffic light) the UIM won't get too hot so quick. Wood is a great heat insulator, and trying to keep as much of the incoming air as cool as possible for as long as possible is what I'm trying to accomplish (along with the heat shield under the UIM). Seems to work though!

[IsaacHayes]

I know people ice their plenum, and that seems to work. I suppose the plenum holds more air than the lower where the air is moving fast, and has more of a chance to warm it up. To keep your plenum really cold, disable and disconnect the EGR pipe too! That's gotta warm it up some!!

[prophiseer]

Considered it . . . but with the PCM controlled EGR and my 02 sensors still in working order, I know I'll get a DTC . . . even if I just blocked the EGR port.

If anyone has any ideas to disable the EGR without setting any DTC's, I'm open for suggestions!

[IsaacHayes]

Yes, the digital EGR can't be fooled by any means. When I meant disable, that means editing the computer code. if you have a 94-95 3100 like me, then we are SOL on that though.

[bszopi]

When I had my regrind in, I never got any EGR codes. Even now, with a basically stock 3400, if I pay attention to my driving, I can drive without setting the EGR code.

[IsaacHayes]

I could drive too without setting it, but it was a PITA, and you'd want to cruise and not be modulating the throttle all the time just to avoid the code..
So brad you don't have an EGR adapter on your 3400 right now?

[bszopi]

Haven't had my EGR hooked up since I first fitted the large port manifold onto the old 3100. I don't even have it plugged in and sitting in the engine bay. It is actually in a box in my basement with the connector dangling...

[Darin]

Would you like me to send you the AutoCAD file? Might need a little work to get them to work flawlessly with a laser/waterjet, but I have the basic design already done.

Brad, Can you send me your CAD file? I will talk to my machinist about making a run of these.

[bszopi]

Do you want me to fix it up or just send it as is? I should be able to get it ready in the next day or 2 if you want to wait.