I want to remove "the shelf" on my 3.5 IM and make an adapter plate for the TB. So I would be chucking the elbow. What's the best way to cut out the shelf?

 

I just did this today, and I just used hacksaw blade and dremel to cut the shelf. took me about three hours to remove IM, cut the shelf, clean, and reinstall

 

How is the power? Are you using the elbow?

 

Yea, I'm still using the elbow, but there's definitely more pull on high end. I'd say about 10-15 whp. and I feel almost no loss on low end.

 

Dont mean to sound new but I seem to be lost... but very interested. What are you reffering to when you say "shelf"?

 

If you disconnect the elbow of the 3.5 intake manifold you'll see a butterfly valve that looks similar to a throttle body next to a shelf. It's an integral part of the 3.5 variable intake. Removing it will give you more top end power, but at the expense of low end torque.

 

Oh.. thanks for the info... much appreciated!

 

What does the shelf do? Is it more of a restriction than a function??

 

No, it has a function and that is to be a vary the effective length of the intake runners. If you cut it out, it is no longer a variable intake and the runners become shorter. Cutting it out makes the plenum bigger and the runners shorter.

 

Sawzaw and a dremel w/ cutting wheel.

 

The "shelf" is a Plenum volume divider/restricter, and the VIAS opens a valve to allow for the volume to increase. Thus more top end. This is simpler and cheaper to use than a variable runner length IM. I am not positive which is necessarily better since both runner length and plenum volume are important aspects of an IM.

The only VQ manifold that has variable runners is the Pathfinder VQ35. All other variable VQ manifolds are based on Plenum volume. This includes all of the FWD VQ35s, the MEVI, and the 00VI/DEk manifold. The RWD VQ35s including the "rev up" and the HR and VQ30DET are all nonvariable.

The FWD VQ35 IM already have large, short runners and increasing the plenum volume by removing the "shelf" or "VIAS delete" it allows for more top end for very little time and almost no money. Some loss of low end is possible, so be warned. Although the VQ35 has quite a bit, and some tuning can also compensate and gain back much of it if not more.

 

Aside from losing low end power, are there any other downsides to it?? And about how much torque would you estimate losing?

I am currently doing the 3.5 swap and I came across this thread, which interests me a whole lot. I am willing to sacrifice low end power to gain top end, afterall, the VQ's are already torquee as hell!

What I'm really curious about is if it would still allow the VIAS to work properly.

I really dont know too much about the 3.5's intake manifold and/or variable intake manifolds but I really would want to learn more about it and get the best performance out of the engine.
Like you all at one point... I'm just trying to do my research.

 

No one's really done a dyno. SR20DE has this mod and has dyno'd numerous times, but he has VTC's which helps out immensely with low end torque, so he loses less low end torque than us with the A32 ECUs would.

If you didn't like the low and mid range torque loss, you can always buy another IM from car-part.com for cheap.


As others have said, the shelf is an integral part of the VIAS. Remove the shelf and you no longer have a VIAS. Just like if you remove the crankshaft, you no longer really have a functional engine.
If you remove the elbow from the 3.5 IM, it will be clear what we're all talking about. It's as easy as pie if the engine is not in the car. Just remove 4 bolts.

 

Thanks again!!!

Aside from the larger displacement, I always thought the VIAS was a huge contribution towards the power the 3.5's produce.

This is amazing to me! The many options we have with this motor.

I think I read somewhere here that someone had done the swap but the car was running sluggish because of the VIAS was not connected. That would be because the butterfly valve was closed and it was interfering with air flow right??

 

If you don't have an RPM switch the VIAS becomes inactive and stuck in the open position which would be the high RPM position. In this scenario, your low and mid range torque will suffer.

It's not clear whether removing the shelf will help or hurt your low end torque compared to an open VIAS. The difference between a working and a functional VIAS is about 30ftlbs of torque up until about 4000rpm.

 

Who has dynos to prove "no loss" of low end?

 

Who made the assertion that there would be no loss of low end torque?

 

..............

I would just like some of you guys to post before/after dynos of this thing.

 

. . . . . . .

 

it was my gut dyno, but now I've been driving for awhile, I actually feel some loss on low end torque, but nothing big

 

So am I understanding this right??

 

you have it backwards

 

There is a low - mid range loss, but can be made up by other means.

 

thanx for the reference dyno NMexMAX. I love how the it holds HP at a plateu from the previous stock peak onto redline.

Question, its obvious that the shelf inside the IM is removed and everything is smoothed out. BUT what about the shelf in the elbow? Is that also cut out off as far as the sawshall can reach n smoothed with the dremel as well?

 

those numbers seem a little low. Do you not have headers?

 

and what other means would those b, have any suggestions?

 

No do not bother with shelf in elbow its only half way in there and the two runners stacked on the elbow are kind of oval in shape and they pinch together where they meet.

theres only couple inches in on the big end where its wide everywhere else on the elbow shelf is very close together.

 

That is backwards, Reverse the top and low. It also looks more like a dual runner setup from what I can tell. Is that from an 02+ FSM? If you take one apart it becomes pretty obvious what we are talking about.

 

I can make more whp @ 6700 RPM than even the most elite (stock manifold eqiupped FWD VQ35's) can. I have another dyno where I make 230 @ 6k, but what do peak #'s mean?


PM me if the run files are needed. Here's a more 'clear; graph.....

 

Its actually off of a 04 FSM.

 

02 VIAS FSM = 04 VIAS FSM... Again and again, the 02+ is not a true dual.