Unhooked my VVIS, what a difference

nsxlover

nsxlover

Experienced Member
Joined
6 April 2002
Messages
1,095
Location
Wrightsville, Pa
I unhooked my VVIS and I have to say it is a must for all FI cars. I went from 454RWHP to 512RWHP. You can feel the difference just driving the car. The turbos would spool to 16.5 psi, then go down to about 13, they now hold 16.5psi with no problem. Also, don't forget to clean your air filters as I didn't realize how dirty mine were.

Rob
 
Interesting... why would unhooking VVIS result in more power? Is it simple to do? Is it dangerous? If you could make this much free FI power it's hard to imagine someone else hasn't done this before.:confused:
 
Not to sound ignorant, but what is a VVIS?
 
Did you lose any torque down low? From reading that thread, it looks like it would be a compromise. You lose some torque down low to gain some horsepower up top. Can you please post your before and after dyno graphs?
 
I didn't really look, but can go back to the shop to get the printout. It wouldn't bother me to loose 10ft/lbs down low, because I never drive it down low. If I am racing, I have the revs up all the time. I will go to the shop early next week to have them print out both dyno runs and post them. The seat of the pants feel is significant, and it spools up so fast, I don't notice any difference down below. I am not an expert, but would recommend it based on my results.
 
If it wouldn't be to much of a hassle!

I can see that in your case it wouldn't matter to much. You already get great low end torque because you are running a TT setup. However, I have a BBSC which suffers in the torque department. In my case, it wouldn't be worth it for more top end. I am definitely interested to see the results though :smile:
 
nsxlover said:
I didn't really look, but can go back to the shop to get the printout. It wouldn't bother me to loose 10ft/lbs down low, because I never drive it down low. If I am racing, I have the revs up all the time. I will go to the shop early next week to have them print out both dyno runs and post them. The seat of the pants feel is significant, and it spools up so fast, I don't notice any difference down below. I am not an expert, but would recommend it based on my results.
Click to expand...


Hey Rob-

What shop did you go to?
 
Rob, have you sprayed with the VVIS removed? as for the torque the n20 will respond with massive amounts down low.let me know the outcome when you try it.
with the VVIS gone a dual stage n20 setup would be in order,stage one would be able to spool up a very big turbo or twins in your case fast as hell not just at the top of the band ....zero lag with a very small shot and stage two would become the primary. just my 02
best regards david
 
My turbo install was done by Factor X. My throttle body has two vaccuum lines that have been cut (the hoses were cut but not capped). They are both from steel tubes pointing downward. One is toward the left of the intake (front of the car). The other is toward the right of the intake (rear of the car).

Is either of these tubes the VVIS?

What are these two tubes for?

Should they be capped?

How can I tell if the butterflies have been removed?

Any commens would be greatly appreciated.
 
Last edited:
Shumdit said:
Man, you ruined it! I was going to wait for someone to ask about doing it on the CTSC and bust them!:biggrin: :biggrin: :biggrin:
Click to expand...
Didn't VVIS suppose to give us the growl noise at around 4500rpm? I don't recall missing that growl after CTSC.
 
Well...got it unhooked on my HP Single Turbo car...all I can say is...WOW. Had to head straight to my tuner though....my AFR's went from 11.8 @ 8000 to 12.5 by 6800 (little high for my taste :eek: )

After adding a little more fuel....everything was good! Haven't dyno'd it yet...but back to back pulls w/ it hooked and unhooked said there was a very large and noticeable difference. Maybe now its time to head to the dyno! :biggrin:

PS....the torque loss in the 3k-4k range was definitely noticeable....but WELL WORTH THE TOP END GAIN!!!!!!!!!
 
Shumdit said:
It would certainly hurt the performance of an NA model.
Click to expand...

Yep, the phenomenon is based on the throttle body/intake manifold being pressurized... when NA, there is only vacuum.

See the link to the old thread, above in post #8.... I was one of the FI 'prototypes' that stumbled upon this, in 2004
 

Similar threads

neuronbob
Comparison between my turbo’ed NSX and near stock.
Replies
18
Views
3K
neuronbob
neuronbob
A
Did Timing Belt Change without Tilting Engine.....
Replies
14
Views
4K
AcuraNSX
A
RC-DEVIL
New Injector Innovation for NSX
2
Replies
40
Views
15K
Honcho
Honcho
D
It's Been A Long Time Coming...
2
Replies
42
Views
14K
darcon
D
Jinks
What parts should be replaced during a motor out?
Replies
9
Views
2K
brettowen
brettowen
Back
Top