I recently received my JR M45 supercharger for the 1.8 to install on my BP-6D (not debating super vs turbo here I already know turbo is better, thank you)
I plan to run an intercooler (accepting suggestions for this too) and know the idle and low end is an incredible pain without the dual throttle body mod.

My question is what throttle body(s) should I get?
a 94-97 or 99-05 style?

my Flat top manifold already has the NB throttle body. so i planned to leave that with its TPS and IAC on the manifold.
unless the NA8 TB is better for the intake side, then I would move the NB model to the supercharger.

I also was thinking of buying 1 or 2 knock off skunk2 throttle bodies as they are 64 mm and the same price as used oem TBs (will be chiseling and loctiteing the throttle plate, and every screw)
again would NA or NB be better here? and if I only bought 1, what side should it go on?

I have a MS3 pro and an electrical engineer brother who is helping with wiring so I can use whatever TPS, IAC setup, I just want the best option.

 

I don't think your going to see any performance difference one way or the other from the parts you mentioned so just go with what's easiest to install.

 

Your pre-SC throttle body needs to be much wider, because the system will be pulling in uncompressed air fro the atmosphere through that.
Your best bet will be a 70mm ford throttle body.

If you have an 64 mm tb, use it on the IM.

I had great results with 70 / 64 mm TBs on my MP62 setup back in the day.

 

Whatever fits the bolt patterns you have on the IM and SC inlet adapter. The M45 doesn't flow enough air to realize enough of a performance advantage from a larger throttle bore to muck around.

 

Was hoping to get your input, Love your build thread.
I saw reference to the ford TB but no one ever mentioned what car to get them from.
That makes sense that the pre SC TB should be big as possible to let it get as much as possible to compress.

 

I know the M45 is going to be a wall, but I enjoy working against it, finding ways to increase the efficiency of a system is fun.
and ultimately I'm stuck buying at least 1 throttle body, so I may as well put in the effort to find what one of the bunch would be, at least theoretically, best.

 

I am telling you, as somebody who has installed JRSCs several times, and implemented/charaterized essentially all potential performance improvements....

Use the TB that fits on the SC inlet adapter. There is more than 1 variant of the bolt pattern there, so the TB you get will depend on the version you have.

The space back there is tight, the JRSC elbow has a funky shape for a reason. Getting away from that piece is dubious.

SC inlet flow through the TB is not one of the limiting factors here. Changing the TB will not result in a measurable performance improvement.

 

oh I see what you are saying now, yeah when I test fit the SC the other day, I had to keep turning the TB to find the way it fit. and then the IAC was hitting (didn't want to remove if its going to stay on the intake side)
What about using a adapter plate to use a 1.6 TB, i have 2 of those, provided that it fits and all.

 

I think it is unlikely you will even have enough room for the adapter plate.

 

This. You won't have room. It is tiiiight back there.

Just get whatever fits. The biggest thing is going to be getting the timing between the two throttle bodies correct. I never got the hand off to work quite right. Any time I hit -10inhg it would jump right up to -3inhg as it handed off between which throttle body was actually doing the throttling.

 

The only way I was ultimately able to solve this was to go to a single throttle-stock location configuration with a diverter. Side note: IIRC I came to the conclusion that the dither here was due to timing delays with the bypass actuator and the vac signal line.

 

A. Don’t rely on your EE brother too much. All he’s going to say is splice those wires together and you’ll need to figure out how to mix an NA and NB tune together, which slightly defeats the purpose of PNP. You’ll need to tune this yourself.

B. A big throttle body won’t work on an M45. It has a different mounting design than Mp62s. A Skunk2 might mount, but I think it’s longer size might make it physically impossible so close of the firewall.

C. What you’re primarily concerned with is how to mount 2 throttle cables to one of the throttles. Decide which TB is going to have two cables and how you’ll mount them and how the throttle cables will be routed from the pedal, and to the slave throttle. Seriously, do this carefully so you’re very clear on how you’ll route it and how the cables pull.

D. Look at the throttle wheel. Many that previously did a DTb mod had access to aftermarket kits that allowed easy installation of a second TB cable. Not available anymore. So you need to figure it out on your own. Ensure your Tab has two cylindrical holes for two cable barrels, or buy an adapter. Have not tried this one, but it’s the only one I’ve seen available anymore.

https://www.shapeways.com/product/7S...pulley-adapter

Notice in the pic, it has provisions for 2 barrels, but needed and adapter for the second cable guide. IIRC, it was the automatic transmission TBs that were the easy button though, as they had 2 barrel locations and cable guides.

 

The NA6 throttle bodies had two cable guides. I lucked on on that and it made doing dual throttle bodies "easy" (it was still a pita to get it all set up.)