Bored Throttle Body, P2R Spacer, and P2R Thermal Gaskets Installed by CleanCL

7 minute read

Bored Throttle Body, P2R Spacer, and P2R Thermal Gaskets Installed 

Compliments of CleanCL @ https://acurazine.com

5-12-2009

This went on my 2009 TL SH-AWD.

Summary of changes:
-Bored Throttle Body by P2R (79mm to 82mm inlet / 69mm to 72mm outlet)
-Throttle Body Spacer with Thermal Gaskets by P2R
-Intake Manifold Thermal Gaskets by P2R
-Throttle Body coolant bypass

Duration of Work: 1.5 hrs with a few breaks

Impressions:
The throttle body is HUGE. This is the largest Honda throttle body I have ever seen. The port job is smooth, and the butterfly plate was replaced with a thinner and obviously larger one. The P2R parts are high quality and fit like a glove. I had no problems at all getting everything back together. The intake manifold went from scorching hot to touch, to luke warm at best. The throttle body remained cool to touch after 5 minute warm up, 10 minute test drive, and 5 minute idle.

Results:
Car turned over smooth, with perfect idle. I felt immediate gains down low contrary to what I expected. Typically with this work, I expect high end gains. But I felt like I only had to feather the pedal to cruise around the neighborhood. The first few WOT you could tell the ECU was relearning (I did NOT reset it) but it got smoother and smoother. I was not expecting anything seat of the pants, but it is asking for higher revs every time. Throttle body temperature dropped dramatically from the coolant bypass, it was VERY hot initially, but now it is cool. My temp reads after the installwere between 90 and 100 degrees. Also the intake manifold was around 100 degrees. Unfortunately I did not get before temperature readings. :[ Overall I'm very happy with this and can't wait to rev it out on the highway.

Thanks to Sean at P2R (http://powerrevracing.com/) and Josh at Excelerate (http://excelerateperformance.com/) for making this all happen. I'm very happy with the results.

And yes, I took pictures.

P2R Spacer and Thermal Gaskets

Bored Throttle Body

Stock Inlet 79mm to Bored Inlet 82mm

Stock Taper 69mm to Bored Taper 72mm

Intake Manifold Thermal Gasket Installed

Spacer with Thermal Gaskets Installed

Coolant Bypass, if you follow the 2 hot hoses on the bottom of the throttle body, these are the inlet/outlet feeds. I just took one of the hoses and looped them together.

And this is the silver hose that part of the coolant runs through. You will notice that also the crank case is ventilated into the intake tube. Before the install, the coolant and crank case air was burning hot and dumping into the intake. Now it is a A LOT cooler. Eventually I plan to replace this with a hose and filter to keep oil out of the throttle body.

5-13-2009

Better throttle response, more volume in the intake chamber, and cooler temperatures... which results in some freed up horsepower. Results on the 3.2L Type S motors showed solid gains between 5-10whp and torque across most of the RPM band. With our 3.5L and 3.7L motors I suspect the gains would be closer to the bigger number.

Also one thing to note, on the 3.7L motor, there is no need to port the intake manifold. The throttle body inlet is larger than even the ported throttle body. Also the lower runner ports are perfectly matched with the gaskets and if you ported those would require honing the gaskets larger as well.

Honestly, I don't remember the exact breakdown with the bore added on. Contact Josh at Excelerate (http://excelerateperformance.com/) as he is a vendor here and sells the P2R parts.

I will write up a quick how-to, but keep in mind I've worked on a lot of these J motors so I did this all blind without any instructions in front of me. But it's very easy to this all, took me 1.5hrs and I took some breaks. I could do it all again in an hour.

5-18-2009

Well I have the part # for the throttle body... I actually have my stock one as shown in the pictures above so if anyone is local to NY with a FWD TL, we could easily test fitment... if you e-mail www.oemacuraparts.com they reply with the 09 part numbers. I've dealt with them alot and only order OEM parts from them. But here is the part # for 2009 TL SH-AWD Throttle body: 16400-RKG-A01

5-23-2009

I have an update to this...

As I said, once you bypass the coolant on the throttle body, it makes most of that silver pipe useless. I got some 1/2" heater hose and 1/2" barb. I zip tied the vacuum part seen in the before picture to the cross bar.

Before:

Parts removed:

Parts used:

After

If anyone is interested I have some leftover heater hose and barb that I can sell to one person. I always buy extra just in case, but this turned out to be pretty simple, just passing it on to anyone else interested. PM me.

5-24-2009

The smaller pipe on the bottom was for the coolant that ran to the throttle body. Since I bypass it, there was just the larger pipe going from the valve cover to the intake. It seemed unnecessary so I just cleaned it up with a single hose.

5-29-2009

It is cheaper to port the stock one, but this is my only car so I can't do much downtime. I also now have the ability to return to stock and sell my ported one when the time comes. I use http://oemacuraparts.com/ for all my parts, their the best price and awesome customer service.

6-4-2009

Well I've been running these for a few weeks now. Combined with pulling out the resonator stuff, the car breathes a lot better. Throttle response is much better and mid range feels more powerful. I no longer have to downshift 2 gears to pass people on the highway, I can downshift once and the car moves much better than before at 3,000-4,500 rpm.