[royce]

bristlenose2008 wrote:

Can anyone tell me what the short runner intake manifolds do for a 4WD like my Suzuki Vitara? Would this make absolutely no sense considering for an off road vehicle?

Short Runners Intake Manifold SOHC 16V

Not seen a bigger waste of time posted on here in a long while

Consider that it would likely end up being a $3000 exercise once you get throttle bodies, injectors, new ECU, tune etc youll end up with less power unless your cam is specced with that in mind

And it will never be better down low

[Damo]

royce wrote:

bristlenose2008 wrote:

Can anyone tell me what the short runner intake manifolds do for a 4WD like my Suzuki Vitara? Would this make absolutely no sense considering for an off road vehicle?

Short Runners Intake Manifold SOHC 16V

Not seen a bigger waste of time posted on here in a long while

Consider that it would likely end up being a $3000 exercise once you get throttle bodies, injectors, new ECU, tune etc youll end up with less power unless your cam is specced with that in mind

And it will never be better down low

On the website it says "approx gain 10hp". Not what you'd call a good ROI

[JrZook]

royce wrote:

bristlenose2008 wrote:

Can anyone tell me what the short runner intake manifolds do for a 4WD like my Suzuki Vitara? Would this make absolutely no sense considering for an off road vehicle?

Short Runners Intake Manifold SOHC 16V

Not seen a bigger waste of time posted on here in a long while

Consider that it would likely end up being a $3000 exercise once you get throttle bodies, injectors, new ECU, tune etc youll end up with less power unless your cam is specced with that in mind

And it will never be better down low

Explain to me Mr Royce.......

[royce]

JrZook wrote:

royce wrote:

bristlenose2008 wrote:

Can anyone tell me what the short runner intake manifolds do for a 4WD like my Suzuki Vitara? Would this make absolutely no sense considering for an off road vehicle?

Short Runners Intake Manifold SOHC 16V

Not seen a bigger waste of time posted on here in a long while

Consider that it would likely end up being a $3000 exercise once you get throttle bodies, injectors, new ECU, tune etc youll end up with less power unless your cam is specced with that in mind

And it will never be better down low

Explain to me Mr Royce.......

For the same reason we know exhaust size effects power delivery due to gas speed so does the intake, longer runners gets more power at lower revs (but then becomes a restriction higher up)

Plenum volume also plays a big part in torque delivery

[JrZook]

royce wrote:

JrZook wrote:

royce wrote:

bristlenose2008 wrote:

Can anyone tell me what the short runner intake manifolds do for a 4WD like my Suzuki Vitara? Would this make absolutely no sense considering for an off road vehicle?

Short Runners Intake Manifold SOHC 16V

Not seen a bigger waste of time posted on here in a long while

Consider that it would likely end up being a $3000 exercise once you get throttle bodies, injectors, new ECU, tune etc youll end up with less power unless your cam is specced with that in mind

And it will never be better down low

Explain to me Mr Royce.......

For the same reason we know exhaust size effects power delivery due to gas speed so does the intake, longer runners gets more power at lower revs (but then becomes a restriction higher up)

Plenum volume also plays a big part in torque delivery

The other way to increase gas speed with short runners down low is to reduce the ITB size (which will cause restriction up high) or use those CV type ITBs.

IMO the G16MPFI intake manifold is not the best of designs flow wise leading to intake air charge robbing and uneven distribution.

[royce]

JrZook wrote:

The other way to increase gas speed with short runners down low is to reduce the ITB size (which will cause restriction up high) or use those CV type ITBs.

IMO the G16MPFI intake manifold is not the best of designs flow wise leading to intake air charge robbing and uneven distribution.

I would like to see some evidence to support this speed increase, otherwise the whole principal of ventruiis would be wrong

I think in flow testing you would find the Vitara manifold to be not too bad and even likely better than a Baleno, Front throttle bodies suck

[JrZook]

royce wrote:

JrZook wrote:

The other way to increase gas speed with short runners down low is to reduce the ITB size (which will cause restriction up high) or use those CV type ITBs.

IMO the G16MPFI intake manifold is not the best of designs flow wise leading to intake air charge robbing and uneven distribution.

I would like to see some evidence to support this speed increase, otherwise the whole principal of ventruiis would be wrong

I think in flow testing you would find the Vitara manifold to be not too bad and even likely better than a Baleno, Front throttle bodies suck

Could check with a vacuum gauge connected up to the runner. Greater vacuum for a constant speed (constant engine air flow) would have to result in greater air speed.

Only descent mod I could see with the stock vit MPFI mani would be to to centralize the TB on the plenum and maybe extend the plenum so it necks down more nicely to the TB.

[royce]

JrZook wrote:

Could check with a vacuum gauge connected up to the runner. Greater vacuum for a constant speed (constant engine air flow) would have to result in greater air speed.

greater vacuum would only mean greater restriction, otherwise throttle butterlfys would work in reverse

[bristlenose2008]

It's time to give an update.

The engine has finally run in, and soon the dyno will tell me if there had been much gains.

I certainly expected more performance from the build than I am feeling driving around town.
The gains aren't too noticeable and many of you G16 EFI owners would have hard time picking up on the improvement.

The Good outcomes
* It appears to reach peak power about 4500RPM rather than 5000RPM
* It maintains peak power even at 6300RPM and dies off after the red line, not on the red line
* revs up a bit faster
* clutch is super grippy
* tappets are very quiet
* engine is super smooth. Revving and idling is not shaking the car, just always smooth. (could maybe be the result of bottom end balancing)
* above 100Kms/hr the car appears to be performing better, with a desire to keep climb ....... , without revving as hard.

The not so Good outcomes
* can not feel the improvement from the higher CR - ie: responsiveness doesn't feel any better (maybe need a Haltech ECU or similar)
* maximum power seems unchanged
* I am more than $1500 over budget


No Sports exhaust has been fitted past the extractors. This is where there I may be needing to make the improvement, this could be what is preventing the extra horse powers from being released.
Of course the factory ECU would also be a restricting matter.

[skyman]

If you still have any stock exhaust hanging on there, that would be the reason you are not seeing much of a gain.

[youda]

also take into account the angle the runners direct the air at the valves. a slight change of angle can give gains or huge losses.

usually short runners = high power at high rpm
long runners = better torque at low rpm.

9.5 to 1 is fine compression supercharger with a good tuner.
mitsubishi evos run up to 24psi on 9.5 comp. (obviously intake cooling is setup to be very efficient).

[bristlenose2008]

thanks SKYMAN & YOUDA

The rest of the exhaust system is on the list before Xmas, maybe
2.5" hi flow cat and 2" exhaust. Perhaps I should go 2.25" or 2.5"

Not sure what would be recommended given that I have a fairly worked head.