ok as you all know, as per Honda Challenge rules, we are limited to an OEM intake manifold. ITR is the best choice obviously, but thats not so great for us running a GSR head. ive been thinking about what all is needed to do to fit the ITR manifold on the GSR head, and theres a serious lack of information on what all is exactly needed. i know the ports are a slightly different shape, and only the bottom bolt holes line up. also just by looking at pictures the coolant passages are not only a different shape, but the coolant hole on the ITR looks to be about an inch higher. ive seens some people say that you need to weld and reshape the coolant holes on either the manifold, head, or both. and to me this doesnt fit the rules defined in section 16.3.g of the HC rulebook "items that attach to the head (IM) may be redrilled for fitment purposes ONLY. Alteration of air, fuel and/or coolant passages is prohibited." then theres the problem of what gasket to use, you will probably need to make your own.

so ive been kicking around the idea of making an adapter plate to convert from the mani to the head. and use stock gaskets on each side. GSR for the head side, and ITR for the mani side. you will still have to redrill the manifold for the bolt pattern, but under the rules this is still legal. im planning to make a plate 3/8" thick AL plate to adapt the different port shape and different coolant hole locations. obviously extended IM studs will be necessary. i already have them on my head. mine are about 35mm long (from the surface on the head) whereas the stock ones are about 25mm

now my questions... has this been done before? is this legal? i dont see anything against anything like this in the rule book. and what are your overall opinions? unfortunately an item like this will have to be handmade. CNC isnt really an option since many cuts will have to go through the plate at an angle because of different size and shape of things on different sides of the plate. ill probably cut out the basic holes and then clean it up with a dremel/grinder/sandpaper.

 

I think that's in the spirit of the rules... though it doens't mention it directly.

Have you considered a B18C5 head? Maybe some PCT pistons too? (sorry, not being helpful)

-Chris

 

yea ive considered the b16/itr head. but considering i have over 2000 into this GSR head, i kinda wanna work with it i like the gsr head better anyway. just preference.

 

modding the itr IM to fit the b18c gsr head should be easier than making an adapter. you just have to drill a few holes to make the bolts/studs fit, drill one larger hole and tap it for the water tube, and you're pretty much good to go. you can then angle-mill the flange a bit for a better runner-to-port entry angle, and finesse the runners and/or ports to match. if a phenolic spacer is legal, get some of the plastic material, trace your ports onto contact paper, stick it to the material, and cut to size.

 

the thing is you cant alter the coolant passages at all. its illegal. and from what ive seen in pictures, the coolant passages arent anywhere close enough to each other where "finessing" would work. the ITR coolant holes look about an inch higer then the gsr. on top of being a different shape.

you can see the difference here in placement of the coolant passage here

 

can you hack that piece out of the manifold and just run a direct line?

 

Another thought-

The head is free, you could get creative on the head side to get the coolant closer to where it needs to go.

 

i dont think so. that would be altering coolant passage, and the manifold. like i said, the ONLY thing thats allowed is drilling holes for mounting, and portmatching 1" int the mani. nothing else.

 

there was a thread about doing this awhile back, don't remeber much about it though, he did have pictures.

good luck finding the topic!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by slammed_93_hatch &raquo;</TD></TR><TR><TD CLASS="quote">there was a thread about doing this awhile back, don't remeber much about it though, he did have pictures.

good luck finding the topic!</TD></TR></TABLE>
You're such a tease, Jimmy...

 

I believe the HC rules don't state that the intake manifold MUST be an OEM part (ie: has OEM part number) but that it must be of OEM style and composition. Thus you can purchase Skunk or Blox "ITR style" intake manifolds that have the GSR flange on them.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by thawley &raquo;</TD></TR><TR><TD CLASS="quote">
You're such a tease, Jimmy...</TD></TR></TABLE>

hahaha just trying to help him out.
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by C-speed &raquo;</TD></TR><TR><TD CLASS="quote">I believe the HC rules don't state that the intake manifold MUST be an OEM part (ie: has OEM part number) but that it must be of OEM style and composition. Thus you can purchase Skunk or Blox "ITR style" intake manifolds that have the GSR flange on them.</TD></TR></TABLE>

thats news to me.

IIRC IT HAS TO be OEM, and so does the TB

see im not just a tease

this thread talks about it also https://honda-tech.com/zerothread?id=747407

some guy in this thread said he did it https://honda-tech.com/zerothread?id=549020

here is another idea, cut the flange off the GSR IM, and cut the ITR IM off of its flange. then weld the ITR IM to the GSR flange.note: I HAVE ZERO clue if this would be legal. and if i were you id probably check it out first


Modified by slammed_93_hatch at 12:49 PM 2/13/2006

 

yes, it HAS to be OEM. i have no doubt about that.

16.3.f - "throttle bodies and intake manifolds are not considered part of the cylinder head and must be unmodified Honda parts. Port matching is allowed but cannot be machined beyond 1" into the intake."

16.3.g - "items (such as throttle bodies and intake manifolds) that attach to the cylinder head may be re-drilled for fitment purposes ONLY. Alteration of air, fuel and/or coolant passages is not permitted. fitment modifications that alter air, fuel and/or coolant passages as a side affect will be deemed illegal"

and the head preparation is free. but one, im not sure if the coolant port can be modded enough to move it to the correct position, and it really not want to go that route anyway. just not feeling modding the head. id really like to leave it alone, just in case i decide to go back to the gsr mani for whatever reason.

i htink since when i buy the aluminum plate it will be 36" long, enough to make 2 plates. i think im gonna make one with the coolant holes, and one with it blocked off and see which one i like.

 

and thnaks for the links slammed. ive read them but already though. i remember the one thread about it, but i havent been able to find it, ive searched high and low.

but i dont think cutting the flange off and putting it on the ITR mani would be legal, mainly due to "unmoddified" part

 

Should have double checked the rulebook before posting.. my bad. Got confused with the SPU class I run locally in ICSCC.

Guess i have to swap IM's when i double enter now.. uber gay

 

Why would you want coolant in the IM on a race car anyway? I would think you would want to block it off on the head side and reshape the ports on the head side, both of which should be legal.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DR &raquo;</TD></TR><TR><TD CLASS="quote">Why would you want coolant in the IM on a race car anyway? I would think you would want to block it off on the head side and reshape the ports on the head side, both of which should be legal.</TD></TR></TABLE>

Correct. I agree. You can easily modify the ITR manifold by redrilling the bolt holes to fit the GSR head. Block off the coolant passage on the GSR head using an NPT plug (thread the hole).

If you really want to maintain heater function, the run coolant to the heater by teeing coolant from another coolant hose.

:D

 

hondata makes a race gasket for the b series that blocks off the coolant passage BTW.

And another thought is that by removing the secondary valves a pretty big gain can be made in overall airflow.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DR &raquo;</TD></TR><TR><TD CLASS="quote">Why would you want coolant in the IM on a race car anyway? I would think you would want to block it off on the head side and reshape the ports on the head side, both of which should be legal.</TD></TR></TABLE>

im just not sure about blocking it off completely.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by C-speed &raquo;</TD></TR><TR><TD CLASS="quote">Correct. I agree. You can easily modify the ITR manifold by redrilling the bolt holes to fit the GSR head. Block off the coolant passage on the GSR head using an NPT plug (thread the hole).

If you really want to maintain heater function, the run coolant to the heater by teeing coolant from another coolant hose.

:D</TD></TR></TABLE>
the NPT plug sounds like a decent idea. but looking a the head id need a 1/2" NPT plug, and theres not much material to cut threads (hole opens up into the head). so im not sure how well that would work. although it is a good idea, and something ill look into.

and i dont really care about heater function, ive already removed the heater core and controls. but im not too sure that that coolant hose from the IM goes to the heater. but i COULD be wrong, i just dont remember messing with that coolant line at all when removing the heater core. but if i did block it off i would T the IACV from somewhere else for sure, and bypass the TB to keep it cooler.

even if i do block it off, im still gonna make this plate. 1, i just wan to see if its possible. 2. im gonna make 2 versions of the plate anyway (with and without the coolant ports) 3. i still want to have something to adapt the different port shapes to have some nicer air flow rather then jumping from one size to the other.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by suavacito &raquo;</TD></TR><TR><TD CLASS="quote">hondata makes a race gasket for the b series that blocks off the coolant passage BTW.

And another thought is that by removing the secondary valves a pretty big gain can be made in overall airflow.</TD></TR></TABLE>

thanks, i thought i remembered seeing gaskets that didnt have the coolant hole cut out. but removing the secondaries is illegal. cant do it.

 

all it says is a stock manifold. Obviuosly lots of other stock parts have been removed from an engine on a racecar. I'm not saying to port it just remove the plunger and associated parts.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by suavacito &raquo;</TD></TR><TR><TD CLASS="quote">And another thought is that by removing the secondary valves a pretty big gain can be made in overall airflow.</TD></TR></TABLE>

But you kill midrange power doing this.

Flow isnt everything.

 

I know but so does swapping to an ITR manifold. At least this way it doesn't cost anything and depending on the gearing it may not matter much anyway.

Personnally I would leave it as is but open the secondaries sooner

 

"stock unmodified" removing the secondaries would be modifiying it, hence illegal.

 

the spirit was to prohibit people from cutting the manifold open, porting and modifying it and welding it back up or worse.

since your not gaining much by doing this other than mechaical simplicity there should be no reason why this should not be allowed. Your not modifying it your simply removing uneeded parts just like cruise control

I mean the rules don't say the IACV valve can be modified but if your using a JDM motor it's going to most likely be. Or how about advancing the dizzy or anything not specifically covered.

Anyway you can argue or you can ask your local region official or go to the nasa board and ask. There are people who I assume have been allowed this looking at there cars. And if your bringing up making an adapter plate rather than following the rules which is "hence illegal" I don't understand your response anyway.

All I tied to do was offer solutions to your problems which is how to get a better flowing IM on a GSR head

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by suavacito &raquo;</TD></TR><TR><TD CLASS="quote">
since your not gaining much by doing this other than mechaical simplicity there should be no reason why this should not be allowed. Your not modifying it your simply removing uneeded parts just like cruise control </TD></TR></TABLE>

But the rules dont say that its allowed. Therefore, its not. There are specific allowances for things like cruise control removal. Doesnt matter whether it "should be" or not.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by suavacito &raquo;</TD></TR><TR><TD CLASS="quote">I mean the rules don't say the IACV valve can be modified but if your using a JDM motor it's going to most likely be. Or how about advancing the dizzy or anything not specifically covered.</TD></TR></TABLE>

Advancing the dizzy is covered in the factory service manual as stock spec.