Hey guys-

I was on 300ZX club the other day and found a thread on this topic.

http://www.300zxclub.com/showthread.php?t=24027

What do you guys think about the throttle body mod?

 

I'm not signing up for another damn forum .............

 

OK, fine. Here the details of the mod.

Throttle Body Mod..

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thanks to MrMoSpo for this one and video


Hey Folks,

At our last Tampa Z meet, a bud pointed out that when we open
the throttle, a tab on the connecting shaft butts against a stop,
keeping the butterfly valves from opening all the way.

He had heard the reason for this was that it was Nissans way of keeping HP
within limits ... lawyers, federal regs, insurance, and such.

A careful look confirms that there's another 5 - 7 degrees to go
before the throttle is truly at full open!


Actually, at least on my 93, there is an adjusting screw/stop at
the linkage of the left/right connecting rods. That adjusts balance
between the banks. But the tab which restricts the overall throw
of the connecting rod/butterflies has no adjustment screw. Equally,
there is no adjustment on the stop. It's just a stump of the aluminum cast.

(FYI the earlier cars have an adjustment screw stop in this location.)

Step on the gas, and the cable rotates the connecting rod until
that bare tab(ear) coming off the rod smacks into the stump of aluminum on the plenum.

To all TT folks, take careful notice as to just how far away from
parallel our butterflies are stopped!


http://www.300zxclub.com/faq/videos/ThrottleMod.wmv

 

thats actually pretty cool, imma check that out cause that's really interesting. To think Nissan would try to jip us horsepower freaks out of a couple extra ponies.

 

Thanks, Looks like I'll be grinding away some aluminum this weekend.

 

How would that lower HP? To me it would seem like this is a rev limiter to a point. All I think grinding that down would do is allow you to rev higher and probably get a higher top speed. Am I right with this thought or am I stupid

 

Opening the butterfly in the throttle body allows air to flow by. Nissan limits the amount the butterflys can open, thereby limiting airflow and potential HP. Max airflow is achieved when the butterfly is at 90 degrees.

Limiting butterfly movement could also be done for design considerations, ie: max airflow is achieved at that restricted opening as it relates to the injector or valve train efficeincy. Only a dyno could answer that tho.

 

That's what I'm thinking. Also, if you look at the angle of the intake hoses into the TB's, it looks like the butterfly is open at about that same angle; which would equate to it being open at 90 degrees. Another thing is this,...if you're car is already running lean; adding more air would be a bad thing. I'd like to see some dyno results.

Another thing I've read about is removing the screen from the MAF. I read somewhere that it increases the airflow through the MAF from 400CFM to 700CFM. I don't see how that's possible, but I've been wrong before. I've also read that the screen helps reduce turbulence through the MAF and allow it to meter the air properly, so removing the screen would be a bad thing if this is true. It's only other purpose is to protect the meter inside of the MAF. So, unless you're air filter fails, you shouldn't have a problem with that. I've read some people have noticed an improvement while others have hhad problems after doing this. This would be another thing where I would want to see dyno results.

 

I have to agree with CanyonCarver and 91zxtt.
There is a lot of talk about this mod but I have seen nothing to show that anyone has documented proof of even a 1 HP gain. On the flip side, there is nothing to show that this mod has caused anybody any grief so at worst it becomes a "so what" or "nothing to lose" idea.

 

whoa that's an old thread. I don't think that mod does much if anything.

CanyonCarver, if one was to sign up for another forum, that would be the one. Although you can quite easily get lost in it. It's really big with all sections being about the Z32 save a slight handfull. I'd recommend it to anyone that has, used to have, or will have a Z32. Just like this forum.

 

OOOOOOOKAY, I signed up.. .... there goes another 15 minutes outta every day.

 

you're right, there's a wealth of info there....... thanks.