Intake Manifold Bypass EASY POWER GAIN!

INFORMATION Articles / Teg Tips
1

Hey guys,
This is a mod done mostly on H series engines. I havent found any write ups on how to do this on B series engines and I figured it out over the winter so I figured I might as well do a write up on it! :up:

Basically what your gonna do is take the coolant that would normally run through the throttle body, fast idle valve, and electronic idle air control valve and back into the water pipe. This just take the coolant that would run from the upper radiator hose and just sends it straight back to the water pipe behind the thermostat! Instead of running through the manifold :cool:

This cause a vacuum leak in the fast idle valve so you need some sheet metal and rtv to use as a block off plate between the fast idle valve and the manifold. This in turn causes your cold start idle to be much lower and you’ll also never get the hunting idle problem again! On cold start my idle is at 1100 rpm (750 when warm) which is much easier on the engine’s rings! :up:

Parts you’ll need:
2 Feet of Hose (I bought 3 just to be safe)
Rtv silicone
Small piece of sheet metal
4 vacuum caps

Tools needed:
Screw drivers to undo intake and hose clamps
Channel locks to undo hose clamps
10mm ratchet and extension to take off fast idle valve


First take off your intake


This is the first hose to take off its runs from the upper radiator hose to the throttle body. This is where the new hose you bought will go the other end of this new hose will go the the water pipe behind the thermostat, easiest way to get to that hose is from under the car, it is above the oil filter.


Now that there is no hose on the throttle body plug up the opening with a vacuum cap :up:


Next remove the “U” shape hose from under the manifold on the back side and place vacuum caps in place of this hose.

There is one more hose under the intake manifold that runs to the water pipe. Remove this hose from the intake manifold on the top side of the engine (this is the easiest way to get to this part of the hose) then go underneath the car and remove the hose from above the oil filter, run the new hose you bought from this spout above the oil filter to the front of the head under the upper radiator hose.


Next undo the 3 10mm bolts on the fast idle valve and put the sheet metal with rtv inbetween the fast idle valve and the manifold


Next remove the coolant line that run to the fast idle valve the bottom hose its here remove this hose and the top one and use the “U” shaped hose you removed from the back of the manifold the loop this.

After all of this fill your engine up with coolant place your intake back on and allow for the rtv to seal then start up you engine! :up: if all works well it should idle at around 1100 - 1250 rpm on cold start with no fluctuation!

Feel free to post and questions you have and I will answer them! :up:

2

sweet write up! Bump for a fellow North Carolinian, btw my crew and a few others will be hosting an old school meet sometime, do you use CH?

3

How much power is gained?

4

YO im so down for a meet i dont know of hardly any da’s around me haha theres like 5 built ones around me and what is ch?

5

At that point it all depend on the temperature of the air, ive never dynoed so I dont wanna throw out a number,my teg but jumping from being waxxed by manual tegs to beating them and keeping up with a gsr. I think thats a bit of an improvement :up:

6

Goofy question but I’m guessing the hoses are all the same size?

7

Is your mpg still the same.

8

yeah i just pulled off the hose to the back of the block that goes to the intake manifold and took ot to oriellys to measure em up and get a longer one to goto the head! :up:

9

I got 40ish mpg on the way to the beach if that says anything haha

10

in TB is a FITV and if you bypass coolant it affects your cold start - its not really important if you live in all-year warm part of the world, but if you reach temps like 10-20 below 0 Celsius it makes you to put foot at acceleration pedal just to keep car running until it warms up a little

IMO this wont give you any noticeable difference in power :slight_smile:

11

[QUOTE=soldi;2318217]in TB is a FITV and if you bypass coolant it affects your cold start - its not really important if you live in all-year warm part of the world, but if you reach temps like 10-20 below 0 Celsius it makes you to put foot at acceleration pedal just to keep car running until it warms up a little

IMO this wont give you any noticeable difference in power :)[/QUOTE]

im pretty sure it made a noticable differnce my auto matic ls is keeping up with dc4 gsr’s :ohyeah:

12

That is zero proof, what if the GSR has a shitty driver or isn’t up to par? Also its DC2 or DB8 for GSR

too many variables in that setup

13

bypassing coolant wont make intake air temperature colder, so it wont act at afr so it wont make engine to perform better

14

it has proven gains on h series motors so whats so different about a b series

15

where is the proof?

16

ive found some on some prelude forums cant find the prelude dyno sheet again, found it for a trans am. didnt look hard, gains are gains. http://www.angelfire.com/ny2/96transam/tb.html

17

thats roughly 2% of gain :wink: clean your air filter and you will get more :smiley:

just dont believe it will make noticeable difference with stock engine

18

my air filter stays clean, who doesnt clean their filter regularlyand gains are gains its 5 dollars to get a couple horsepower

19

Great…apparently this mod adds 40hp and a wider rpm range!? There is no way a stock auto LS would beat a manual GSR because of a coolant line relocation. If you did, that GSR driver is rubbish.

I did this exact thing on a previous DA I had. I noticed absolutely no difference. But I think any mods that reduces heat is great. Its easy to do and eliminate elements that can cause issues (heat and iacv)