# Quad Throttle Bodies?



## himilefrontier (Jan 21, 2003)

Well, this is not a question limited to just Nissans, but a more general question about TPS sensors. I am planning a sort of odd Hybrid, an Austin Mini with a Honda D16Z6 (It runs, and it's free, plus there are plans on the net for how to use it in this 1200lb car). Problem is, the engine bay in this tiny old British car is VERY short, too short for the stock intake manifold. I can however possibly fit a set of Quad throttlebodies off of a sportbike on the engine (GSXR, Hayabusa, etc) with a custom fabricated manifold. My big question is, are TPS sensors calibrated in a "Universal " fashion, as they have the same resistance at closed throttle and all have the same at WOT? Or are they different from brand to brand? If they are universal, you could use any throttlebody on any engine it is properly sized for so long as you can mount it. This opens alot of doors for people hoping up 4 cyl's as you could also adapt cast off LS1 TB's to SR20's etc.Also, would this setup run dead lean because the Speed Density fuel injection the D16Z6 comes with is unable to compensate for the increased volume of air? Thanks for any time and thought you can give to this.

(P.S. I know many here hate the H brand, but I also considered a GA16DE, SR20DE, Mitsu 4G63 , a few motorcycle engines, GM's Ecotec and Toyota 4AGE but this came along free in exchange for help with a swap, and I am not rich, so I have to take it.)


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## WhiteFox (Sep 4, 2002)

Well, I don't know everything about everything, but here goes one to think on.

At idle, the butterfly is pretty close to (if not completely) closed. Count that as 0 degrees. 
Fully open, it should be rotated at about 90 degrees.
(might be a few less, just example)

Unless there's some odd reason for it not to open fully or it rotates past it's end point, I'd say any TPS should be able to be used. (In the mechanical sense)


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## ReVerm (Jan 13, 2003)

himilefrontier said:


> My big question is, are TPS sensors calibrated in a "Universal " fashion, as they have the same resistance at closed throttle and all have the same at WOT? Or are they different from brand to brand? If they are universal, you could use any throttlebody on any engine it is properly sized for so long as you can mount it.


Unfortunately, TPS voltage isn't quite universal. With some cars, it's very similar, but with others, it's completely different (Mustang TPS's go up to almost twice the voltage that the SR20DE one does). I'm not sure what kind of figures you'll get with motorcycle throttle bodies, but I'd play it safe and assume that the voltages won't match up until you measure it all out.

I can't give you any specific information about the D series though. Sorry.

Definately sounds like an interesting swap. I know this isn't an Austin/Honda forum but please let us know if it works out (maybe slap a post in the Off-topic section or something). Thanks.


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## Dwntyme (Dec 18, 2002)

It's been done.... saw this at NOPI last year.......


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## ReVerm (Jan 13, 2003)

Dwntyme said:


> It's been done.... saw this at NOPI last year.......


Personally, I'm not interested in seeing whether it's been done or not, but rather how the finished product would function.


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## Dwntyme (Dec 18, 2002)

damn just trying to send you in some sort of dirrection......search....then....

bump
bump
vump


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## himilefrontier (Jan 21, 2003)

I have done PLENTY of searching (for 6 mos and have 40 sites bookmarked!!!!) and have E-Mailed a guy who has just such a car. I have posted this idea in OT before, but was unsure about the TB issue. I figured I would ask since one of my alternate engines is a GA16DE and it would apply there too.
If you are interested in seeing what this exact swap looks like (without the quad TB's) look at this site. It's so comprehensive it's almost spooky! http://minimikebc.tripod.com/index.html 

(P.S.I was hoping someone here had experience with quad TB's and that's why I put this post here.)


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## niky (Jul 20, 2002)

quad TBs are easy if you're converting back to carburated... be easier to tune, too...

Sorry, only dude I know with an EFI engine converted to quad TBs took the ITB assembly off of a 20V toyota engine and put it on a Mazda FSDE... looks like it would be easy, as the Toyota ITBs have an external trigger for the TPS... might be possible to gear it and find an approximate ratio between the throttle play and the honda engine's stock TPS.

Since they come off of a 2 liter engine, they'd probably fit with little hassle, and give you a hell of a lot more air for future modding.

Only hassle I can remember from using quads in the past is a lot of engine bogging at low rpms if they're not tuned right. 

EDIT: Oh yah, just remembered... the non-turbo SR20 used in the Tommykaira and in the Primera BTCC racers (240 and 300hp respectively) are both quad throttle... but I've heard that the Tommykaira SR20 tends to bog a lot at low rpms. :wtf:


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