P2R Throttle Body Spacer FAQ's

[xxmstajxx]

I blocked off the coolant the my TB when i first got my Si.....

also I just bought the TBG TBS TBG from Corsport in a special color.....yahhhhh pics soon

[BTRobertson]

Originally Posted by bizzybearfigiblue

omgosh bro... ur running super lean... my car has never dyno'd that lean... i'm around 10-11 AFR in higher rpms... that's rich i know but that's stock too

Actually, that's not that lean and it's right where it should be. I've seen AFRs up into the 15's, which is far too lean, I'll grant. From what I understand about our cars, 13's/14's are a good mix to produce power without overheating the engine. Anyone else have info on this?

Also, this from my speed shop guy when I emailed him about the full bottom end to top end results of my car over bone stock:

Your car had more power bottom to top than the bone stock one. - Denis

We're off topic anyway - this is the spacer thread and we're talking intakes. Once I dyno with my spacer on prior to installing the race header, I'll post the gains and charts here.

[BTRobertson]

I promised pictures for some users regarding the fit of the P2R TBS/G with the Fujita F5 SRI. What we did was create a bracket extension for the F5 mount instead of trimming the rubber inlet hosing. Why? Well, you're shortening the air travel path, which will mess with the AFR, even if slightly, because you're changing the flow dynamics. That was my theory anyway, albeit untested. So, here's two pics: one of the spacer installed (seen before) and one of the custom bracket extension we made out of a simple piece of scrap metal lying around the shop. Enjoy.

[SiliconX]

^ That's a pretty slick idea. I didn't even think of that.

[michinsi]

Originally Posted by BTRobertson

I promised pictures for some users regarding the fit of the P2R TBS/G with the Fujita F5 SRI. What we did was create a bracket extension for the F5 mount instead of trimming the rubber inlet hosing. Why? Well, you're shortening the air travel path, which will mess with the AFR, even if slightly, because you're changing the flow dynamics. That was my theory anyway, albeit untested. So, here's two pics: one of the spacer installed (seen before) and one of the custom bracket extension we made out of a simple piece of scrap metal lying around the shop. Enjoy.

Thanks for the pixs. :) I see what you were talking bout now...my used AEM SRI never even came with a bracket...

[Gixstars]

a nooby question. What is the purpose of the coolant bypass? why do it? what happens if you don't do it? what happens if you do it? ty all

[firstsi]

Originally Posted by Gixstars

a nooby question. What is the purpose of the coolant bypass? why do it? what happens if you don't do it? what happens if you do it? ty all

the throttlebody has a radiator line running through it, to warm the air going in to the engine

by bypassing the throttlebody you get cooler, heavier, denser air in

[OrdnanceMarine]

Originally Posted by Gixstars

a nooby question. What is the purpose of the coolant bypass? why do it? what happens if you don't do it? what happens if you do it? ty all

Honda runs coolant to the throttle body in order to make absolutely sure you can't get any sort of icing in the area. Ice near the throttle plate *could* crack off and cause damage downstream (possibly valves). The second, more realistic possibility is that if you were driving in the right conditions you could get ice to form where it could keep the throttle from closing when you take your foot off of the gas, essentially causing a runaway engine. To get this you would need a perfect combination of air temperature and humidity which I think is nearly impossible to have.

That being said, there is still *some* controversy regarding doing this here but many members have been doing it on the K20Z3 for a while and have done it on other cars for many, many years.

That being said (again), I have done the coolant bypass on my throttle body. If I'm ever concerned about the slim possibility of icing in the winter time then I will reconnect the hoses (takes maybe 10 minutes) and I'm back to stock.

To me there seems to be no point in trying to get cooler, more dense air to the engine by using tricks such as a CAI or using the intake manifold gasket if you are still heating the air at the throttle body. In theory you should see a slight decrease in MPG doing this since WARM air often better for fuel economy but I can't say I've seen any change. I get exceptional fuel economy.

[Gixstars]

thanks firstsi and ordinancemarine. one more thing. if you do the bypass, where do you bypass it to? as in where does that hose go? To ordinancemarine, you say you have exceptional gas mileage w/ or w/out the IMG? what are you running? (intake, spacer, gaskets, tb, etc.)? i'm all for gas mileage

[OrdnanceMarine]

Originally Posted by Gixstars

thanks firstsi and ordinancemarine. one more thing. if you do the bypass, where do you bypass it to? as in where does that hose go? To ordinancemarine, you say you have exceptional gas mileage w/ or w/out the IMG? what are you running? (intake, spacer, gaskets, tb, etc.)? i'm all for gas mileage

Find the two hoses that attach to the bottom of the throttle body. Follow them back to the engine (one attaches to the black coolant "manifold" that runs to the heater core I believe). Pull one off of the throttle body and loop it back to the port right next to it. Pull one off of the engine and loop it back to the other port and you're basically done.

Other tips:
-I took a funnel and poured water to flush the throttle body, then blew it out with my air compressor to completely dry it out.
-You can partially drain your coolant into a clean bucket for reuse. This keeps you from having to deal with leaking coolant when you disconnect the hoses. I didn't do this on my car and it made a bit of a mess. I lost probably a cup of coolant. On my friends Si we were changing his upper radiator hose to a flexible stainless one and installing the IMG at the same time so we had drained the coolant, making this even easier.

I believe there is a DIY on this. Use common sense as with any mod!

[OrdnanceMarine]

Originally Posted by Gixstars

To ordinancemarine, you say you have exceptional gas mileage w/ or w/out the IMG? what are you running? (intake, spacer, gaskets, tb, etc.)? i'm all for gas mileage

I have all of the basic mods besides an intake (check my profile for details) and I'm able to wring out great mileage, better than many EXs and this was all with a car that hadn't had it first oil change until last week at 4100 miles. Check out the mileage thread on the Si page if you want to learn more about how to boost your mileage. I expected to see a slight reduction in mileage after installing the IMG and doing the TB coolant bypass because while cooler air does equal more available power it usually means lower efficiency. It would take some time to explain why but it has mostly to do with the fact that gasoline engines like ours have a throttle that modulates airflow.

The bottom line is I haven't noticed anything but my mileage getting better and better. All I can conclude is that a combination of my engine breaking in, temperatures getting warmer, gasoline switching to "summer blends", and me learning how to drive my car more efficiently has netted huge improvements in mileage over the past four months I've owned my car.