So, I did search to see if this has been answered, but plugging any combo of "intake" and "manifold" makes search a PITA. Skimmed like 25+ pages of stuff.

Anyway.

How is the flow/design of the 94-97 intake manifold compared to the later NB manifolds? We all know the head flows better, but both NB IMs have a bunch of "stuff" in them and make getting to the fuel rail a royal PITA.
What I am wondering is, might there be any benefit to hacking the flange off a 01+ IM and mating up the NA 1.8 IM?

I have a spare 01+ IM sitting under my bench and would be willing to try this.

 

I'm going to guess that the later im's with vics and vtcs flow more..

Would be nice to see some real testing/results though.

 

I'm going to guess that the VICS mani flows better than the VTCS simply because the VTCS sits directly in the path of the runners and does not offer a performance improvement whatsoever.

 

FWIW, I THINK that Actor from m.net ran both the VICS and the VTCS manis on his VVT motor and made more power with the VICS mani with VICS operational. This was in an n/a configuration.

I still don't understand the issue with getting to the fuel rail in a VICS mani. I found that it was easy to unbolt the top half and once done, yielded better access to the rail than even the B6 im. YMMV?

 

Really not comparing the VICS to the VTCS here... seeking information on...

this IM...



vs this in terms of flow/design

 

Ok, sorry to pollute.

But, correct me if I'm wrong here. Since the ports in the HEAD are more vertically-oriented on the 4W/Z3 vs the BP, wouldn't the runners in the IM be similarly oriented. In this case, I would think the transition angle between a BP IM to the 4W/Z3 head would be very disruptive to flow...

Now, is there any way to get back to MY interests in your thread?

 

Um, more. Looking at the VICS mani (not sure about the VTCS), the biggest impediment to flow, I would think, is that ugliness just downstream of the TB. If anyone has a pic, it's obvious. Unfortunately, it's part of the casting shape.

 

Yeah, the elbow..which some people have "throated" to get rid of. That's part of my motivation about looking into the NA 1.8 intake manifold because of the more direct path of airflow.

Webby- No problem. That question is another aspect that I am looking to answer. IIRC the orientation of the IM on the flange is the differnce between the two. Since I have the VTCS mani at home, I'm looking to aquire a BP IM to do some comparisons with.

 

I’m running a 95 manifold on a 99 head.

I cut the head flange off it and welded on a new one to fit the 99 head.

While I was at it I cut all the features associated with EGR off it along with extra bracing and such. Filled in the hole left by the EGR stuff with a welded in plate and welded everything up and smoothed it out so it looks nice like it was cast that way. I gasket matched and sort of hand ported the runners as much as I could get to.

I don’t have any A to B comparisons but it looks good and makes acceptable power.

Bob

 

I was under the impression that a gutted 99-00 manifold was about as good as it gets, except for the uber rare JDM manifold which has a bigger plenum from the factory.

 

Finally..real-world usage. Do you have any pics to share Bob? What were your thoughts when looking at the manifolds side by side? (runner diameter/length/design)

According to some, it's good for top-end power and dyno numbers, but ends up with a reduction in mid-range and torque (read- Turns101 posted about this in his search for better spool and tq). I'd still like to get a WDM mani, but it's not easy.

 

I think the 99 manifold gutted and opened up will loose a bunch of midrange torqe based on my fiddling around on a NA car with out means to control the butterflies. Again this is an unscientific seat of the pants measurement.

FWIW My car was making 320+ FT-lbs by 4000 rpm on a Dyno-Dynamics dyno at sea level. A walup of transmission exploding torque. It is possible that it could be improved on for upper end power. It seems my car starts running out of breath by 7000rpm. In theory you could tune both ranges with a 99 manifold design assuming it flowed well.

I will try and dig up some pictures tonight.

Bob

 

You need dis

 

Yeah, seen that. But that's expensive in terms of what the cost of a NA/NB hybrid could be....and still requires the same modifications after purchacing the Honda mani. It would be cool if someone would make those Miata-ready.

 

Gut the VTCS out of the 01+ Manifold. Almost easier done than said. Let the VVT head do the rest.

 

 

Gutting a manifold takes a shitload of time and is fairly messy. Not sure where you're getting "easier done then said".
VVT won't make up for airflow restrictions/limitations of the manifold.

 

I think he means removing the VTCS butterflies, not gutting the plenum.
Im not sure what all goes into it but it may be possible to pull those suckers out of there and JB weld up the throttle shaft holes.

 

Yeah, once you get the manifold out, it's easy to remove the VTCS, but while taking the time to remove the IM...why not replace with something with even more gains?


ismel....GFY

 

I still hope to find a fair price one