The FIT Manifold Transplant

[SFLA-Z]

Again per the box and label, the Genuine Honda Part #17110-RB1-000 Intake Manifold Chamber for the Honda Fit, is slightly bulkier and heavier than my 2011 base CR-Z (6MT)'s oem Manifold Chamber, obviously the throttle body and intake runner openings are identical in size and locations, but furthermore, the internal size and contour of both manifold chambers appears visually identical, the four intake runners are identical in lengths and diameters since they can be measure on the underside, and the inside of the chamber has no resonators of sorts, it has seven total interior openings: four for the intake runners on the manifold, one for the throttle body, one for the MAP sensor, and one for the brake vacuum hose; no additional openings inside. In hindsight, which I'd not have done anyways, but one of our forum members might check, is to temporarily close the each manifold chamber's thottle body end water-tight to a flat surface and measure water as each is filled, and I'm certain that both will contain the same measure of volume, and confirm my measurements and visual inspection (provided the correct Honda part belongs to the box that was sent to me).

I noticed that in addition to the Fit's integral one-piece engine cover / intake manifold chamber, many hollow stiffener-ribs (not open to the inside) flanked the four intake pipe runners, and the Fit's chamber appeared heftier; maybe the stiffer chamber moves / vibrates less through the engine rpm range, where the air boundary layer tends to be disrupted less and air flow tends to be more laminar, rather than occasional turbulent disturbance in the less stiff CR-Z chamber (good for combustion, bad for intake flow). This is one explanation for the dyno numbers and drivability observations noted by modifiers, which can't be ignored. However, this speculation can't overturn my serious doubts after personal physical inspection of the specific manifold chamber sent to me.

[teknicalissue]

I ordered the Manifold and It should be arriving by this friday. If all goes well I can probably do the water volume test on both the stock cr-z manifold and the Fit's

I'm also going to do some MPG testing as well with just the fit manifold and no other mods.

I'll post the results on sunday at the latest

[SFLA-Z]

Another difference with the two intake manifold chambers (IMC) is that they may have different steady-state heat retention behaviors, where the Fit (IMC) 's heftier and flanked intake runners (heat sink) absorbs less heat from the valvetrain cover (heat source) below, and the CR-Z 's additional 'engine cover' over its (IMC) retains heat coming up from the valvetrain cover below; again, my unsupported speculation in an attempt to explain two apparent identical internal sectioned (IMC)s producing different performance results on the same engine.

On filling your chamber with water, the holes for the MAP sensor and brake vacuum hose will also need to be capped, and to be safe I'd blow it out with a hairdryer before installation. Do you plan on holding the throttle-body end against a neoprene pad. Also, I supect that when you see the two manifolds, you'll conclude that they're internally identical with no need for volumme measurement.

As you may know already, pages 9-5 thru 9-7 of the CR-Z service manual covers removal and installation of the (IMC) including: the 3-stage / inside-to-out / criss-cross bolt tightenening sequence to 18 lb-ft. for the five chamber-to-manifold mounting bolts, and the loosening of the intake mounting bolts at the (IMC) throttle body end and sequenced (specific order) re-tightening of these bolts for proper fit. Also, contrary to the service manual, the brake vacuum hose is best removed last after easing out the unbolted (IMC) for working space to release the hose clip and to pull the hose off. Remember to remove the negative 12v battery terminal before beginning.

[ITEM9]

Intake manifold with torque-enhancing resonator chamber

The intake manifold contains an integrated resonator chamber that takes advantage of the pulse waves from the individual cylinders to produce an air-ramming resonance effect. The capacity and shape of the resonator's chamber and connecting tubes have been tuned to fill in the dip in the i-VTEC engine's torque curve around 3,500 rpm and deliver smoother, more linear driving performance.

Quoted from:

Honda Media Newsroom - Fit - 2009 Honda Fit - Powertrain

[OneFitZ]

Originally Posted by ITEM9

Quoted from:

Honda Media Newsroom - Fit - 2009 Honda Fit - Powertrain

I think that finishes this argument.

[SFLA-Z]

Originally Posted by ITEM9

Quoted from:

Honda Media Newsroom - Fit - 2009 Honda Fit - Powertrain

Thank you so very much! Luckily, I still have my resonator chamber, but I'll need another Sunday for my installation. Your info is also straight from the horse's (Honda's) mouth. I feel badly that I may have caused doubting thomas' in this performance upgrade, but without your cut-away view, I couldn't verify internal differences without actually cutting open the chamber.

[KennyX]

Ok, just ordered a 2010 Fit intake chamber, I want to see the difference. Luckily, HondaPartsCheap ships to Italy.

[Carzee]

Originally Posted by ITEM9

Quoted from:

Honda Media Newsroom - Fit - 2009 Honda Fit - Powertrain

Good find. that's why when you look at the dyno on the very first page you now know why it made +6trq at 3,700. Boom roasted

[OneFitZ]

Fit manifold + BLF CAI probably makes for a nasty 3000-4000 rpm torque line.

[SFLA-Z]

Mission accomplished! The Fit chamber doesn't look as good as the oem engine cover with the IMA label, but I guess function is more important. I can feel a vague increase in performance (the K&N intake and Mugen exhaust performance improvements were more noticeable), but landmarks seem to go by markedly faster on familiar local road straight-aways. Mursepaolao's dyno numbers confirm Honda's stated design intention to raise the dip in torque of the LEA1 at around 3,500 rpm, which I sense is there but hidden by the IMA motor. The dyno numbers also gives a 5 hp boost from 5,200 rpm to redline. I can also confirm the approximate 20 lb-ft of torque drop shown on the dyno graph without (IMA assist), since whenever the 12v battery is disconnected, the 100v nickel-hydrides in the trunk seem to always discharge to zero; during recharge the CR-Z if pushed will be a slug even in sport mode. I was cut-off by a PT Cruiser as we both got onto the main roadway, where he needed to go to the extreeme left-lane and of course dropping-back was not an option for him, with no IMA I was crawling; I'm sorry for Fit owner's with no IMA assist and just 5 forward gears. I think the Fit gets better highway mileage than the CR-Z, but no thanks.

A quick note: The Fit manifold's resonance pulse chamber's bulk, intrudes into the space normally occupied by the CR-Z's purge-valve support bracket (the Fit doesn't have the valve at this location), and so it does not have the female thread to bolt-on the oem bracket. Therefore, the support bracket had to be unclipped from the purge-valve body and abandoned; the lightweight plastic purge valve body is now only supported by the rubber hoses connected to it, and the congestion of emission /coolant hoses and wire harnesses packed into the small area. It's snug and rattle free, but a loss of bracket support is lost with the Fit manifold chamber F.Y.I.