• Hello Guest, welcome to the initial stages of our new platform!
    You can find some additional information about where we are in the process of migrating the board and setting up our new software here

    Thank you for being a part of our community!

16v Intake Manifold Adapter?

Mylesofsmyles

A Member
Joined
Jan 18, 2010
Just wondering why we don't see more of this...

It seems like it'd be a very cost effective solution for fitting a 16v head in a 240...

Just like adapting the 8v Turbo exhaust manifold, why not use a plate adapter to bolt a B230 intake manifold to the 16v head?
 
Yoshifab used to sell them, but stopped. Because it didn't make for a very good bolt-on solution.

1) There's a nasty round 8V runner to oval 16V port transition that leaves all sorts of nasty vertical surfaces hanging out in the airflow.
2) The intake manifold mounting surface on a 16V head is set over a couple of inches and angled up a bit more, so an 8V manifold bolted onto a 16V head still isn't a very good fit in a 240 anyhow - the throttle body still points *right* at the brake master cylinder.

Then there's the fact that the 8V intake just isn't really all that great for higher flowing higher HP applications anyhow.

That being said, I did use a Yoshi intake adapter on my first 16V build. But I did spend a bunch of time porting the head, the adapter, and the intake to make a smooth transition:
IMG_1900.JPG

IMG_1903.JPG

IMG_1904.JPG

IMG_1905.JPG

But spending that much time and effort on a 'bolt on adapter' kind of misses the point.

And when I got the motor back in the car, and the head on the motor, and the intake on the head....
IMG_2005.JPG

IMG_2006.JPG



My git-r-done solution was to hack a short 850 N/A 3" throttle body on, and to carefully bend over the brake line that was most in the way:
IMG_7937.JPG
IMG_2007.JPG


Still had to use a 'tight angle' elbow:
IMG_2030.JPG

This ended up not being intended for pressure, but instead for a turbo inlet. On the dyno I saw it balloon outward a bit under full boost. Still worked fine for a couple of years. heh.

I also had to mangle with the throttle spool and bracket, because they would have been rubbing the hood.


CLIFF'S NOTES: Neat only in casual theory, in practical application not worth it at all.
 
Gotcha.
Not a high hp build...just as simple as a 16v over b230ft can be. It's for my dd

Guess I'll hunt down a short b234 manifold
 
I think he also offered a bolt on adapter to put an 850/960 throttle body on the 8V manifold (it was a curved tube that placed it facing forward), but by the time you bought two adapters you'd already sunk too much money into sticking an 8V manifold on that (as Kenny just said) wasn't such a great manifold to begin with.
 
Reviving this thread to ask is it a good idea to run an intake/exhaust manifold adapter for an 8v manifold to 16v head. My situation is that I want to 16v swap in the future but want to keep my existing intake/exhaust manifolds, or at least just the intake manifold because where the turbo is placed there might be interference with the 16v head. But with the adapters I feel like the smaller port size on the 8v manifolds would reduce my air intake, making it not worth it to 16v swap. Then I was thinking to just cut off the flanges and weld on 16v flanges to open the ports up on the manifolds. I would have a fabricator do it for me. It's not going to happen for a while, just want to start making plans. It's one of those Nathininwa intakes so that's why I want to keep it.
 
Last edited:
Yes, but I'm asking would I see 16v performance benefits with an 8v adapter plate in between the manifolds. I know I wouldn't be seeing maximum airflow but would it be worth while to just run the adapters and get at least some kind of performance benefit? Because he didn't really mention what kind of performance he got out if it. And has it been done to cut the 8v flanges off the intake and exhaust and put 16v ones on. I don't know if it's still a good idea because the manifold runners could be too small in shape/size to even benefit from a bigger 16v opening.
 
Last edited:
the effort involved would be better invested somewhere else, get one of the cast kl-racing (or similar) intake manifolds and move on
 
Yeah I would of thought it wouldn't be worthwhile but for right now, I'd like to hit 400hp. The car is already setup for it, just needs a couple things including a better flowing head. I'm sure I can port my 530 head and run an aggressive cam but that same money can just go to a 16v with aggressive cams(or stock cams not sure yet). And I wouldn't need to swap heads in the future to get more than 400hp. I'm not really interested in the 531 head because the PO put forged RSI Wiseco pistons in that are cut/dished for the 530 head. But yeah I'll hold on to my intake and get a proper 16v intake on when the time comes.
 
Why bother swapping a 16valve head in if youre going to use some **** ass 8valve intake manifold?
 
Last edited:
It's still not a great idea, the round 8V runner just doesn't fit well with the oval 16V port. Ait coming down the runner is going to hit a flat top and bottom of the 16V port sticking out into the airflow. The wider 16 port edges hanging out the other direction probably don't make as much of a problem.

When I did this a long time ago I spent a couple of hours with a die grinder blending the two shapes. I bolted the adapter to the head and smoothed out the top and bottom of the 16V ports, blending it an inch or so back into the head. And then I bolted the adapter to the 8V intake and did the same on the sides. Afterward, it was smooth between all the transitions (8V intake - adapter - 16v head) so I don't think airflow was all that compromised. I guess there's maybe some weirdness going on when the port gets a little bigger in the middle before it gets to the valves?

Probably better to have someone weld on a 16V flange, as you suggested. Although I'd set it on the head in the car and see where the intake sits when it's against the 16V head, Nathan might have made the 8V's a little longer? I'm not sure.

Version 1.0 of my 16V turbo motor had that 8V intake and a log exhaust manifold and some eBay ball bearing turbo, made 300 whp on a bit more boost than it probably should have needed for that much HP. Version 2.0 had a 16V Nathan intake, and RSI header and an EFR turbo, made more power, spooled better, never had that one dynoed but I'd guesstimate it was making 350-ish whp on a bit less boost.
 
The 8v intake is a restriction to the 8v head. It?s been done before and it?s a waste of time, money, and effort.

90+ and adapter is not great either, but works well enough for 400 whp
 
Back
Top