I am in the process of building up my GS-R hybrid del Sol for some medium street performance (forged internals and mild port job; I see a turbo in my future...), and while I have the intake off, I was curious if anyone has had any experience (good or bad) with removing or locking the 2-stage butterflies on the '94+ GS-R intake mani? I know the 2-stage manifold has gotten a fair amount of criticism for being much less efficient than the B16/ITR, and I wondered if just locking the butterflies on the short (high rpm) runners, or removing the butterflies altogether has yielded any good results.

I seriously doubt any good would come of this since Honda went through a lot of work to put it in there, but they are also concerned with mileage and low-rpm drivablilty, so it could be possible to squeeze some more out of it. I mean just removing the butterflies would allow all of the runner to be used and lower restriction.

Tuning would prolly help a little, too, but that is prolly true for a stock GS-R...

Anyway, has anyone messed with the 2-stage intake operation with any luck?

Adrian

'93 del Sol Si w/ '95 B18C1
JE 9.8:1, Eagle Rods, SS undercut/swirl valves, mild port, ITR LSD, etc...

 

Your better off with an ITR or skunk2 manifold buddy.

Its a unique idea but takes away the point - not sure how todo wish i could help

 

the ITR wont fit on a p72 (gsr) head

 

gsr and type r are the same block....

 

if your ready to deal with the loss of low end torque, then be my guest. im not sure if you would have to alter the computer in any way though to compensate for the change in airflow

 

You won't gain anything by removing them. It is actually a very good design. If you are looking for a higher flowing manifold, you have a couple options:
1. Send your manifold off to Erick's racing and have them port it for you.
2. Get an ITR manifold redrilled to accept a GSR head.
3. Go with an aftermarket manifold, like Skunk2 or JG.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by WiggiE &raquo;</TD></TR><TR><TD CLASS="quote">You won't gain anything by removing them. It is actually a very good design. If you are looking for a higher flowing manifold, you have a couple options:
1. Send your manifold off to Erick's racing and have them port it for you.
2. Get an ITR manifold redrilled to accept a GSR head.
3. Go with an aftermarket manifold, like Skunk2 or JG.</TD></TR></TABLE>

I second that.

 

I will work I have done it. You will need to have someone cut out the other runners. This will create a big plenium (sp) and have plenty of volume. However if you do not have the head or the cams to flow the air don't bother. You will lose some torque but gain somewhere between 5-15whp depending on how much you have done to your motor. This is similar to what Alaniz does to Ericks head. Of coarse his are more detailed though.

Good Luck.

 

keep the stock gsr mani and port it out...contact dprracin.com or pyrracing.com for more info on porting the gar mani...i just posted like 6 or 7 pics of the gsr ported mani..

https://honda-tech.com/zerothread?id=674664

i feel that the gsr mani ported esp with new plates for the larger butterfly will have some nice gains...i dont like the skunk2 very much...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by [ iLL &raquo;</TD></TR><TR><TD CLASS="quote"> iNt3GrA]gsr and type r are the same block....</TD></TR></TABLE>

maybe you havent noticed, but the intake manifold goes on the head, not the block, and the heads are different...

 

kmk1605, i was about to post that, beat me to it lol

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by b18c3 &raquo;</TD></TR><TR><TD CLASS="quote">the ITR wont fit on a p72 (gsr) head</TD></TR></TABLE>

it will fit

skunk2 has shorter runners then type-r so it is better... plus you can get a skunk2 for around 300

 

Please explain to us all how a itr IM will fit on a gsr head without drilling the holes?

 

please explain to us all why you bumped a 4 year old thread.

 

EDIT: Didn't realize this guy bumped a 4 year old thread.

 

The OP did his thing years ago.

An ITR IM will not fit a P72 head.

Removing the butterflies in a GSR IM does not produce significant gains in the high RPM but hurts low and mid performance. Just fork over the cash for a single runner IM.

Four years old and locked.