FP-GRN w/oem int vs. Weapon-R on 91 oct.
Anyone who has an inkling of how intake manifolds work and who knows how to use a pocket calculator knows better. In general, the higher the torque peak in the rpm range, the greater of a difference will be observed.
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We might caveat that however by pointing out that the various sheet metal intakes differ as much as chocolate and cheese, and if a particular sheet metal intake stands a chance of reducing performance, that is more likely to happen with a stock turbo application than anything else.
And finally, we have to define what we consider to be a 'gain', as a few more peak power at the expense of softening the torque curve in a fair portion of the usable rpm range won't be beneficial.
It's rarely a simple picture.
Sure.
We might caveat that however by pointing out that the various sheet metal intakes differ as much as chocolate and cheese, and if a particular sheet metal intake stands a chance of reducing performance, that is more likely to happen with a stock turbo application than anything else.
And finally, we have to define what we consider to be a 'gain', as a few more peak power at the expense of softening the torque curve in a fair portion of the usable rpm range won't be beneficial.
It's rarely a simple picture.
We might caveat that however by pointing out that the various sheet metal intakes differ as much as chocolate and cheese, and if a particular sheet metal intake stands a chance of reducing performance, that is more likely to happen with a stock turbo application than anything else.
And finally, we have to define what we consider to be a 'gain', as a few more peak power at the expense of softening the torque curve in a fair portion of the usable rpm range won't be beneficial.
It's rarely a simple picture.
With a stock-ish turbo, you should probably keep plenum size on a sheet metal intake as small as possible (yet bigger than OEM). The standard Magnus and Weapon-R seem to do this. The rest seem more for drag applications.
Considering, with tuning, Aby was able to get this manifold to perform better than OEM for most all of the powerband, I think the positives far outweigh the negatives IMHO. Now, there is more work involved to get the car to respond to the change tuning-wise, but nothing worth doing is always easy...no?
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Sure.
We might caveat that however by pointing out that the various sheet metal intakes differ as much as chocolate and cheese, and if a particular sheet metal intake stands a chance of reducing performance, that is more likely to happen with a stock turbo application than anything else.
And finally, we have to define what we consider to be a 'gain', as a few more peak power at the expense of softening the torque curve in a fair portion of the usable rpm range won't be beneficial.
It's rarely a simple picture.
We might caveat that however by pointing out that the various sheet metal intakes differ as much as chocolate and cheese, and if a particular sheet metal intake stands a chance of reducing performance, that is more likely to happen with a stock turbo application than anything else.
And finally, we have to define what we consider to be a 'gain', as a few more peak power at the expense of softening the torque curve in a fair portion of the usable rpm range won't be beneficial.
It's rarely a simple picture.
the reason why i went for the weapon-r, was due to the smallish runners & plenum, when compared to other brands thati have seen/touched.
i dont believe i lost any power anywhere from what i can tell., by feel or logged data. the transient response is as good down low, compared to my ported oem unit & better once the revs are >4k
on a side note, my wife still thinks the throttle is hyper-sensitive.....she still prefer's the way the hks 280 cams drove in the city
I think that is due to her hootchy mama shoes that she wears @ times.
btw, i am not trying to make the claim that all sheet metal intakes are great on a stock-ish turbo...i am only showing my results / gains for the weapon-r intake vs. ported oem with my mods
That plenum, to my non-engineer eyes, looks a lot bigger than either the standard Magnus or the Weapon-R. But, the proof is in the pudding and until someone bolts one of those up to their car, we'll never know
I come from the SR20DE world. In 1994 Nissan swapped intake manifolds on the SR in the US. They went from short runners to longer runners. The car produced more torque but less hp, though Nissan rated the car the same.
If the runners are too short, this will compromise VE in a majority of the usable rpm range, torque will suffer, and the power band will suffer. This is my concern with the Ku manifold, having only seen photos of it and with no real measurements.
Intake runner resonance peaks can be fairly accurately calculated from runner dimensions (area and length), and knowing the distance from the orifice of the head port to the backside of the intake valve.
Given the spatial constraints between the engine and firewall, my guess (I haven't actually measured it) is that one may not be able to get a runner of ideal length to fit. If this turns out to be the case, it would mean that even manifolds with the longest runners may be shorter than what would be most desirable.
Just a bit of perspective.
Intake runner resonance peaks can be fairly accurately calculated from runner dimensions (area and length), and knowing the distance from the orifice of the head port to the backside of the intake valve.
Given the spatial constraints between the engine and firewall, my guess (I haven't actually measured it) is that one may not be able to get a runner of ideal length to fit. If this turns out to be the case, it would mean that even manifolds with the longest runners may be shorter than what would be most desirable.
Just a bit of perspective.
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i have a straight forwad calculation, measuring from as you described, from back of the intake valve to funnel lip, has been +/- 200 rpm, on engines having rev limiters between 7,200 - 17,400!
funny enough, i got the calculation from a 2 stroke book, published in the late 60's!!
the intake port tube of the weapon-r is small in diameter as well.....i will try to calculate the runner area...the wife has the car today
Hmmm, a 2-stroke has an intake event on every stroke as opposed to every other stroke. I think the calculations would be generally correct, but the harmonics will be an order different between the two types.
Here is another caveat, Ted
With a stock-ish turbo, you should probably keep plenum size on a sheet metal intake as small as possible (yet bigger than OEM). The standard Magnus and Weapon-R seem to do this. The rest seem more for drag applications.
Considering, with tuning, Aby was able to get this manifold to perform better than OEM for most all of the powerband, I think the positives far outweigh the negatives IMHO. Now, there is more work involved to get the car to respond to the change tuning-wise, but nothing worth doing is always easy...no?
With a stock-ish turbo, you should probably keep plenum size on a sheet metal intake as small as possible (yet bigger than OEM). The standard Magnus and Weapon-R seem to do this. The rest seem more for drag applications.
Considering, with tuning, Aby was able to get this manifold to perform better than OEM for most all of the powerband, I think the positives far outweigh the negatives IMHO. Now, there is more work involved to get the car to respond to the change tuning-wise, but nothing worth doing is always easy...no?
you should see ported stock intake manifold in action