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HO throttle body on Renix intake manifold

grover

NAXJA Forum User
Some time ago someone was asking about adapting an HO TB to a Renix intake manifold. I've attached some pix. It's not too pretty as I'm no fabricator :(

The intake was tapped and drilled to accept the Renix TB.

The HO TB had the narrow-diameter ridge at the bottom removed to open up the overall diameter.

The stock throttle cable and automatic transmission cable were kept, although the tranny cable had to be remounted since the existing bracketry no longer worked.

The rubber intake hose from the original Renix setup was kept, but the rubber mounting "flange" was cut off and it was simply clamped onto the HO TB.

Overall, dunno if any power was gained or not, but it really opened up the diameter of the original narrow TB.
 
good job man! notice any difference? if not, did you bore it to a straight 60mm?
 
Hey thanks :) Yeah, I just ground the ridge off the bottom so that it's the same diameter as the rest of the bore (60mm like you said I believe). As far as any differences go, it's hard to tell from the seat-of-pants-ometer... maybe a little more power at wide open throttle, and maybe a little better throttle response off-idle. But it wasn't too dramatic of an increase. Wish I had a dyno ;)

Oh I made a mistake in my post in the 2nd sentence... meant to say "drilled to accept the HO TB" not the Renix TB.
 
cool! I am kind of thinking about this...but I am getting a tbi spacer for my non ho, and a bored tb...soooo im gonna rethink that

however when i do my stroker...i might think about doing it again...

did you do anything to the tps?
 
Didn't have to do much to the TPS itself. I opened up the elongated adjustment slots just a little with a dremel tool (it was quick because it's just plastic) as the 2 mounting screws on the HO TB have a slightly different spacing. Other than that, just carefully bolt the TPS on and adjust to the factory specs.
 
Nice!! I've always wondered if this can be done without making a spacer. There is a writup somewhere about making a spacer to adapt the 3 bolt to 4 bolt. I like this way better though, good job!

Do you have any pics of the intake with the TB removed?
 
I don't have any pics of the intake without the TB, but drilling/tapping the 4 new holes wasn't too bad - just lots of aluminum shavings going everywhere! If you do it, just remember to stuff a rag into the intake so the shavings don't get down in there, and a shop vac is helpful too.

You can line up the HO TB (or just its gasket) to see where to drill the new holes. It takes a little fiddling to get the 4 holes positioned so that they don't interfere with the existing 3 holes, but if I can do it.... :)
 
Good Job!

I have been planning this for my stroker; the manifold is already drilled and when it stops snowing (expect 4 - 8" tonight) I'll put it on mine and try to get some HP comparisons before & after.
 
Great! When the weather breaks, please post your results if possible. I would think it would make a difference since the stock Renix TB appears to be so small... it must be a bottleneck!

After that's opened up, I wonder what the next-largest bottleneck is?
 
just finished my 03 grand c motor conversion in my 88 renix and i used the 03 tps by slotting the mount holes to adjust it and had to make/use a map adjuster to get the needed 5 volts at wot.works great.
 
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