Here's a "how to" on the install of a Hondata intake manifold gasket, "race" setup. The Hondata gasket helps FI/NA setups increase power output by blocking the coolant passage from heating the intake manifold. Decreasing intake manifold heatsoak to the intake charge increases power by as much as 4%, according to Hondata.

The red circle indicates where the gasket blocks the flow of coolant into the head. The JRSC manifold shown throughout this "how to", but the coolant setup is the same on a stock Si.



This is the coolant hose, indicated by green arrows, that is going to be eliminated on the race setup.



To remove the hose carefully slit it with a hobby knife. Make sure you don't scar the brass coolant port.


With the hose removed, bypass the coolant flow as shown below. The bottom portion of the coolant hose is tee'd onto the heater control hose. The 5/8" tee is specifically made for automotive coolant use (it's made by HELP!). The top coolant port is no longer functional since the gasket will block the coolant path.


The acute angle of the hose caused a "kink" in the coolant path, so I opted to install a 90 elbow to maximize coolant flow.


To further decrease heatsoak, you should bypass the throttle body (TB) and intake air control (IAC) coolant passages as well. The 5/16" coolant hose will now flow from this location:



then directly to the main return coolant pipe.


To further optimize the effectiveness of this mod, I chose to install the Hondata washers. The only caveat is to install longer head studs. To remove the existing studs place two nuts as shown below:


then use a wrench on the inner nut to remove the stud:


The replacement studs I used were about 1/4" longer than OE and were made of stainless steel rated for automotive use. Thanks goes out to Sonny (svanhook) and Johnny (JT98civicEX) for explaning the procedure on how to remove the stock studs.


Reinstall the new stud and apply blue loctite.


Longer studs installed:


Studs and gasket installed.


Hondata washers installed.





The manifold is now significantly cooler to the touch compared to the stock setup when the motor is at normal operating temps. There is a noticeable difference in temperature between the head and intake manifold. When the weather warms up I'll compare the intake temperature difference with this new Hondata gasket race setup compared to the datalogs I recorded early Fall.

 

Employee of the Month! You can have the parking space next to the front door now!

thanks, my gasket should be arriving today or tomorrow.

 

Very nice. Many thanks

 

Where did you find those studs from? I've been looking around and I'm looking to buy studs in various sizes. Is there someplace on the web? Thanks.

-Mike

 

what is the point of using the hondata washers ?

 

yes,
please give us size and threads for the studs and a good source.

 

i believe to minimizes the footprint where heat can transfer from the studs.

 

Sonny Van Hook and Zip always giving the great info. I wish you guys posted here more..

art

 

Zip is the man when it comes to SC stuff. Him and Lungredn

 

yeah they're always over at hostboard or something

 

good stuff man....

 

Alright Zip....now I'm confused I'm reading over the instructions from Hondata and it's telling me to drill a few holes in the thermostat, and to reroute the hoses in a different manner...do I have some really old instructions?
Austin

 

The stock studs are 25mm long. You can use these studs, which are 35mm long. They retail for less than a buck each, and you can order them from any Honda or Acura dealer.

92900-08035-1B
Bolt, stud (8X35)

 

Any drawbacks to not having coolant flow to the manifold? I figure there's a reason that Honda ran it there in the first place.

I recall it was perhaps to warm the manifold in cold temperatures...

 

Yes, I would really like to know this as well... Anyone?

 

Hmmm....wouldn't this be a bad thing to do? Coolant flow to the head is important to keep the valves and combustion chamber cool, helping prevent detonation. And head temps will be even higher in a FI car. Someone tell me I am wrong here.

I can understand keeping coolant out of the intake manifold, but not out of the head. Is cooler intake temps worth a hotter head?




[Modified by HXMan, 2:24 PM 2/21/2002]

 

i have always reroutted the coolant hose off of my TB. cause i don't like that funky angled metal piece in the engine bay...never had any problems with that...

 

There is another takeoff hose and the main radiator hose about 3" to 4" away.

 

Also, its not coolant flow TO the head, its coolant flow FROM the head.
Coolant gets to the head from the block and exits the head to the radiator and
to the thermostat housing and heater core.

 

AHhhh....thanks.

 

I bought the studs from an Ace hardware store in the bay area that carries a bunch of metric hardware. Home Depot, Lowes, and Orchards didn't have the metric hardware I needed.


Austin: This an alternative setup compared to the instructions in the Hondata site.

DarksideDC4: sgT is correct, the mod essentially just keeps the flow blocked from the head but coolant still flows away from the head in the main radiator hose.

Here are cross posts, so some questions about this mod may already have been answered on other boards.
http://www.hostboard.com/ubb/Forum40/HTML/009753.html
http://forums.clubsi.com/ubb/Forum12/HTML/010584.html





[Modified by zip, 5:01 PM 2/21/2002]

 

A little bit OT..

but here's a message that I got back from Robert at Hondata about the gasket install..and the necessity to drill the six holes in the thermostat to keep the car from overheating....

==========
Yeah this subject is brought up quite often. (referring to the the need to drill holes)
I would say cut the passage open, we only really recommend the race version
for non-street cars. The gasket will have a positive effect with or without
the passage open.
==========

RA who's unsure as to who to listen to, but will try without the drilling on the Mugen thermostat equipped car.... !

 

Great write up man!

Rob

 

It's about time you post something useful here, Weenie Boy.

Before you guys start flaming me, Zip and I are friends.

Sonny

 

i just finished this install several days ago... thanks for the right up Zip!

the hardest part was removing the old intake manifold gasget!!! geez!