Please read... it's not fluff...

The low-down:

GSR head
GSR Intake Manifold
GSR block... ~1.9L, ~11.5:1 CR,
Stock GSR ObdI ECU
Vafc

The engine runs great, but with the increase in displacement, I have been considering upgrading cams, but not all out (toda,skunk,etc..). ITRs are inexpensive, seem to gain a few horses and are OEM (I like that). I know they bolt up fine, and I would plan to use the ITR springs/retainers.

My concerns:

Even with the redline increased to an ITR's, I have concerns with the GSR intake manifold. As most know, the GSR manifold is a dual runner design, made for both midrange and topend performance, but the better flowing ITR manifold is single runner, superior design. With the ITR cams, would this manifold be a problem with power production ? I have tried driving the car w/ the manifold's runners open and I can feel the loss in the lowend, but mid to top end power come on more smoothly (no kick in the pants at 5800) I prefer to keep the lowend power using the active runner.

*With the GSR ecu mapping the fuel curves assuming a dual runner... can I easily tune in the fuel requirements with an AFC to extract the maximum potential of the ITR cam ?

I plan to tune w/ the GSR cams soon...swapping to ITRs:
*Will the cams comepletely throw off my tuning and require me to start from scratch ?

I do not want to switch to an OBD2 ITR ecu, and I am considering trying Uberdata on my n/a setup as soon as I get enough info... but until then... it's stock ecu w/ afc tuning.

I could purchase an entire ITR head/manifold... but with the cost, drop in compression and ecu/runner issues, I don't think I want to go that way.

Help...
X2

 

Chip your obd1 ecu to run a tuned program.
I made myself one for my b18c1 with ctr cams and stock manifold based off a ITR tune. It's NICE and runs without the butterflies.
I also then learned I could wire up a switch for obd2/obd1 butterfy wiring and now I just tune with the butterflies and change the point at which they open, as well as vtec.
It's NICE. I highly reccomend you chip it and then take it to a tuner or play around.

-Andrew (www.honda-hackers.com)

 

You say 'chip it'... but how do I know the chip i'm running doesn't have too much advance, etc..... ?

And that butterfly switch.... elaborate on that please ! How do you lower it on a pre-burnt chip ? I'd love to be able to lower the rpm where the runners open... I know I'm missing out on some power there now !!!

 

you're not really increasing displacement. The ITR cams will bog a bit when vtec switches at 4400 rpm but the manifold will maintain a good midrange torque output even with the ITR cams. The top end will make more power and the curve will hold longer even with the GSR mnaifold. I cna send you an Eprom for the setup you listed, it will work best and maintain the gsr manifold controls.

Pm me if interested.

Greg

 

i went from stock gsr cams to itr cams in my ls/vtec, and difference was there, but the stock gsr manifold limits you more than you can believe. my suggestion is get yourself a skunk 2 intake manifold to compliment the cams, you will love yourself for it, and your car will love you too

 

there are people out there (such as Erick's Racing) who've made advancements with the GSR intake manifold, by removing the secondary assemblies and doing some porting; wound up making more power over a type-R manifold in fact.

The GSR manifold's 'snailshell' design helps create torque, and with the secondaries removed the top end power is enhanced, so you get the best of both low-end & top-end worlds, whereas the type-r manifold is focused mainly on top end power.

just something you might wanna try with your GSR I/M. But then again, if you do this, you'll definitely want to do something about your ecu programming, VTEC crossover point mainly. A VAFC is highly recommended if decide to go this route.

Your type-R cams should be fine with stock GSR's fuel/timing map programming, and like Cheetah said, a slight bogging when vtec kicks on because of the bigger 'mid' (vtec) lobes.

Type-R cams won't throw your tuning off at all, that is, if you haven't dyno-tuned your car yet (camsprocket tuning), and your car is untuned/running on stock settings, etc. You can drop them in and go.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CHEETAH &raquo;</TD></TR><TR><TD CLASS="quote">you're not really increasing displacement. The ITR cams will bog a bit when vtec switches at 4400 rpm but the manifold will maintain a good midrange torque output even with the ITR cams....</TD></TR></TABLE>


The increase in displacement I was referring to was that my block is bored..... I know cams don't affect displacement.

*What is the x-o point of vtec on an ITR ?

I have noticed that when the runner opens at the stock point on this setup that there is a large increase in power, unlike a stock gsr.... sooo....

*Would reducing the opening rpm of the runner to just after vtec switches over be recommended due to the more extreme lift of the 2ndary lobe (w/ ITR cam)... giving power earlier in the vtec band (as compared to a stock gsr cam) ?

Unfortunately, porting the manifold is out of the question for me at this time... and putting on a skunk2 + ITR cams is out too (to much $$).... plus, I've driven in an ITR w/ skunk2 manifold and top end was great... but lowend sucked monkeybutt.... I need lowend where I drive....

 

Oh yeah... I will be dyno tuning w/ the gsr cams... and putting in the ITR cams at a later date..... hence why I wanted to know if it will affect the tuning negatively....

 

g'mornin'....bump...

 

I have been thinking about doing this mod as well. I would get some sort of V-AFC or hondata to control the fuel maps and to set your cross over point to maximize your gains with the ITR cams.

I would leave the secondary runners alone. They open up late enough that it wont interfere in any way with the cam upgrade, as stock ITR cross over at 5,700RPM anyway. Becuase oh the torque producing nature of the GSR manifold, you wont have to set your VTEC point that high, though. I would suggest starting out at around 5,500 RPM and leave the secondary at 5750. That should be a very good starting point. Or you could just have both your secondaries and VTEC kick in at the same RPM (5,700). That would be one helluva kick in the pants....

 

And, yes, it will affect your tuning. Dont bother tuning untill you get the ITR's in there, unless its going to be a while, then go ahead and make sure you're not running too lean with that CR of yours.

 

I was thinking about keeping a stock GSR IM also and just modifying it. Anyone have pictures of the Erick's Racing GSR IM or details on what exactly they did to it?

 

Good luck on finding what they did to it. Erik's is known for thier secrecy on...well....everything.

 

Anyone have pics of how the engine looks from the outside?