Porting the stock Intake manifold (my write up)

[96cxt]

As many of you may have read my write up on the custom cold air intake system I put together backing it up with dyno of before and after. My next step is the Big Bore Throttle Body (BBTB) and a ported matched intake manifold. I odered the BBTB from SOS and have finished porting the intake manifold. I haven't installed the manifold yet but once I do I'll post the dyno numbers of before and after.
The stock intake manifold is restrictive in my opinion, The runner are narrow and there are alot of imperfection in the casting. I opened up the runners as much as I could and this process took 10 to 12 hours of just porting time. I port matched the BBTB side and had to port the thick rubber spacer that goes between the BBTB and the intake manifold. I also port matched the runners to the manifold gasket, this is the part where the manifold bolts up to the heads.
This should give much more air flow and on a boosted car this would really make a good difference.

The pictures shown of the completed one is going on Scott's NSX, he is getting the Love Fab turbo kit and so I had to get his done so his X can be shipped out this weekend. The other manifold is going to be installed on my NSX which will be NA are dyno will be posted after installation.

THE PORTING BEGINS

HERE is a comparision of the stock runners vs the ported ones
Look at the ones with the gasket sitting on them you can see the amount I have opened up.

Enjoy.
Dyno will be up in the next couple of wks.

Thanks for viewing
Rahim Jamal

 

[adrenaline_nsx]

damn good job Rahim, I dont think i have the patience. hit me up when you go dyno.

 

[theman1990]

Just out of curiosity, wouldn't you polish it a bit more? I understand that you don't want it mirror smooth (don't remember why anymore) but would smoother help or is that "old thinking"? I'm basing that off the hot rod motors i read about and played with in the early 90's.

 

[UnhuZ]

excellent job... did you remove the 6 little throttlebodies??! that would increase even more the airflow :wink:

 

[Zishan]

I didn't even have the patience to let the pictures download. :smile:


Good job Rahim, can't wait to hear Dyno feedback.

 

[davidf]

I had no idea these had internal TB's. Has anyone ran w/out them and is there an advantage/disadvantage to this? Good write up BTW.:wink:

 

[KooLaid]

Help with low end torque. Argument is whether it is beneficial to remove those in NA or FI. The main thought is it is best for FI where the top end gains far exceed the low end losses.

Don't quote me.

 

[Larry Bastanza]

I had no idea these had internal TB's. Has anyone ran w/out them and is there an advantage/disadvantage to this? Good write up BTW.:wink:

SOP if you install a blower

Regards,
LarryB

 

[UnhuZ]

SOP!?!?? :redface:

SOP if you install a blower

Regards,
LarryB

 

[HondaHeat]

SOP : standard operating procedure

In this context it could aslo mean :SOP: "Sucking On the Pipe"- the go fast crack pipe

 

[Hugh]

SOP!?!?? :redface:

Just for you -----> SOP

 

[Hugh]

The pictures shown of the completed one is going on Scott's NSX, he is getting the Love Fab turbo kit and so I had to get his done so his X can be shipped out this weekend. The other manifold is going to be installed on my NSX which will be NA are dyno will be posted after installation.
Thanks for viewing
Rahim Jamal

Rahim,
Would you be able to this for me as well? Please PM me the cost, any additional parts you'll need (new gaskets etc..) and your contact information. I already have the SoS BBTB and this mod is just what the doctor ordered. Your work is meticulous.

Thanks!
Hugh

 

[UnhuZ]

ahhhh... with drawings and animations i get it :wink:

Just for you -----> SOP

 

[Thanhnsx]

Can't wait to see the outcome.

Thanh

 

[swerve2007]

Just out of curiosity, wouldn't you polish it a bit more? I understand that you don't want it mirror smooth (don't remember why anymore) but would smoother help or is that "old thinking"? I'm basing that off the hot rod motors i read about and played with in the early 90's.

for carburetted and port injected cars you want to retain surface roughness to energize the boundary layer (induce turbulence at the walls) to keep the atomized fuel from settling on surfaces. it is not an issue with direct injection or port injection that uses injectors close to the actual intake port, downstream from intake manifold.

 

[96cxt]

Thanks everyone.

Hugh I already Pm'ed you.

David, I'm working on the internal TB plate. I dropped one of to the machine shop to get it machined/gutted so it will only be a spacer. But I'm gonna try to take it one step further. I want to dyno all 3 ways.

1) With the ITB (stock) in place

2) With the ITB (machined/gutted) in place.

3) Completely omiting the plated making the manifold shorter so there would be less volume to fill in the manifold.

If anyone has already tried this please chime in.

Thanks
Rahim

 

[FastraxTurbo]

I did 2 tests. One that was ported and the center divider removed with a machined out TVS plate, and another with a ported manifold with the divider but the TVS plate removed. Both lost mid range torque but peaked slightly higher horsepower. I'll try and find the dynos and post them later.

 

[96cxt]

I did 2 tests. One that was ported and the center divider removed with a machined out TVS plate, and another with a ported manifold with the divider but the TVS plate removed. Both lost mid range torque but peaked slightly higher horsepower. I'll try and find the dynos and post them later.

Was that on a boosted or NA app?
Thanks the graph would help me alot.

 

[doc_tai]

I remember SOS used to sell adapter plate to replace the stock butterfly plate. I dont know they're still selling it or not

 

[theman1990]

for carburetted and port injected cars you want to retain surface roughness to energize the boundary layer (induce turbulence at the walls) to keep the atomized fuel from settling on surfaces. it is not an issue with direct injection or port injection that uses injectors close to the actual intake port, downstream from intake manifold.

Thanks! I was 99% sure that was it, but wanted to confirm!

 

[swerve2007]

in all honesty guys i think you are kinda wasting your efforts on this. if you are going FI then you should just replace the plate altogether with a spacer, otherwise i don't think the slight increase in top hp would warrant all the effort and loss of torque etc. afterall, honda spent a lot of development time to design this feature to produce linear power curve and aid drivability. just my opinion.

 

[FastraxTurbo]

Was that on a boosted or NA app?
Thanks the graph would help me alot.

This was on a NA car. On a boosted application, I think the gains would be appreciable.

 

[greenberet]

Rahim, running those three dyno tests (with stock VVIS plate, with gutted VVIS plate, without VVIS plate) would be great to really document the differences and have a baseline. I've never seen before/after dynos and have been thinking about gutting my VVIS plate myself. I suspect that will get more top-end horsepower than just removing the VVIS plate altogether, but without testing it, it's just a hunch. A test would be great.

adrenaline_nsx and CB169 have removed their VVIS plates and you can find a dyno sheet in this thread (http://www.nsxprime.com/forums/showthread.php?t=118017), but you can't see the difference between before and after.

 

[FastraxTurbo]

Heres a dyno chart.

 

[Mac Attack]

Cool - thanks!

It looks like they are all the same - or any small differences are probably just due to repeatability.

However, it definitely looks like between 3500 - to almost 5000 RPM there is an advantage with the OEM configuration on an N/A application.

Dave