Modified stock plenums to use 86/87 intakes on hotair cars.

[TType84]

I was told this would never work years ago and someone finally took the time to try it himself. This would be a very popular piece for hotair owners provided the cost could be kept down.

I realize this member used an accufab plenum to begin with, but I cant imagine it would be much harder, if at all, to use a stock plenum. Considering stock plenums go for ~$30-40, the only costs in this would be the machinework itself.

 

[cwmccray]

Jeff Scott was the vendor that was modifying the plenums. Here is the link:
Buick HotAir Conversion. He once quoted me $55.00 to mode a plenum. Maybe he will still mod the plenums.

 

[6 to go]

The polished plenum pictured is a Accufab plenum
that I modified myself. That is my 86 manifold,
85 turbo and bracket also.
Jeff did not do this, but told me that he
would do the cutting and welding if someone
would supply the mockup harware to use,
ie manifold, bracket and turbo.
It would be nice if someone would make the plenum,
because to modify the Accufab like I did, gets very
expensive, $250 for the plenum,and milling, welding,
etc just adds to the tab, but a small mod to the casting
tooling and we would have it.
Jeff was modifiying an 84/85 intake in his kit,
I used a stock 86/87 intake.

 

[Daniel Jost]

I have the tools and am working to make a jig to make modded plenums much easier and quicker to make, ill let you know how it goes and ill take some pics soon.

,Dan

 

[6 to go]

Thanks, Dan.
Mark

 

[49-blues]

How is the air flow after the mods?

 

[6 to go]

It sure would be nice to compare flow #'s
on the same intake with unmodified and modified
upper plenums. The 86/87 intake will flow unported,
about the same as the JS Mfg and the TurboMotion
intakes. I don't know of anyone that has stepped up
to the plate to do the flow comparisons, how ever.
I don't know how to get it done and anyway, my
car is running with it and I like the way it runs.
I don't plan on either racing it or putting it on a
dyno. I just did it to prove to myself that it works.
And it works great, IMHO.

 

[Daniel Jost]

Same reason im doing it! I will check for exhaust temps in each cylinder when i get it going to make sure im not running the rear cylinder lean, if i have uneven distribution i will design a few custom power plates on Auto Cad and put them on the CNC cutter until i get it right. I will not get to those results until next summer though, because it is winter not and the weather is crappy out, thats WI for you!

,Dan

 

[6 to go]

Good job, Dan! Real good engineering approach to it.
I like that, I just don't have the tools now.
Mark