KPower Industries K24 swap

[Irace86.2.0]

Steel for me. Still lighter.

[brzlegend]

Originally Posted by captain awesome

There is still some drivetrain noise and some vibration through the shifter but a HUGE amount of vibration has been reduced when in motion. I can place my hand on the trans tunnel and it's considerably smoother than before. I still have the vibration I think is attributed to driveshaft around 3-4k RPM but the majority of buzzing in the interior is gone. There is also still some vibration at idle but even that seems to be lessened.

Originally Posted by wiki

Secondary imbalance produces vibration at twice the frequency of crankshaft rotation.

Because of the finite length of the connecting rod, piston motion is asymmetrical: A piston travels further during the top half of the crankshaft's rotation than during the bottom half - in the same time. Thus the acceleration through TDC is considerably greater than that through BDC and the inertial forces of two pistons (and part of the connecting rods) moving with a phase difference of 180° will not completely cancel out, leaving a net upward force twice per crank revolution. This particularly affects 2 and 4 cylinder inline engines, and above a capacity of about 2.5 litres, they require balance shafts

3k-4k =6k-8k vibration

[captain awesome]

Originally Posted by Swift

If you are running the aluminum flywheel you should be running a Fluiddamper or something.

Steel flywheel but now that you mention it, I wonder if using a Fluiddamper would reduce engine vibes as well? Off to the googles.

[captain awesome]

Originally Posted by brzlegend

3k-4k =6k-8k vibration

I believe this also could be attributed to critical speed on the driveshaft? There would be a 1/2 speed vibration in lower gears and then a full speed vibration in overdrive.

[Icecreamtruk]

I have nothing concrete to add here but I see a lot of incomplete information floating around and I've had to chase my faire share of vibrations on my ls swap.

So people seem to be mixing in vibrations coming from the engine itself to vibrations on the driveshaft, and they really are 2 completely different things.

Primary or secondary imbalance vibrations on the engine are just there in most/all engines, but I4 layouts are one of the worse offenders for secondary imbalance vibrations. So much so that they need counterweight shafts inside the engine (usually towards the rear and low part of the block, almost inside the oil pan) so that they don't shake themselves to pieces basically. I don't know if any of you guys removed any of these, but if you did, big no no for vibrations. These types of vibrations will be felt all the time, but intensity might vary with rpm and load.

Driveshaft vibrations will only present while the car is moving (duh!) and can be caused by a properly imbalanced driveshaft (rare these days), by having incorrect angles (too big, too far from each other) between the driveshaft and the trans and diff (each side of it, basically) or by simply going over the critical speed of the driveshaft. Angles at each end of the driveshaft should be lower than 3 degrees but higher than 1 degree and within 1 degree of each other, otherwise, you'll get vibrations (the farther off, the greater). Critical speed is dependent on the material of the driveshaft, the diameter of it and the length. Usually its ignored (because it never causes a problem on stock cars, since most cars use a 2 piece, which basically halves the length, problem solved), but with aluminum 1piece driveshaft its a real problem, although it will usually be present only at high driveshaft speeds (6-8k rpm at the driveshaft, which is around 100-140mph on a stock final drive car). They will be very present and shake the whole car down, and increase greatly with speed.

I have nothing productive to add to OPs specific problems, just hoping to add some clarity to those chasing some vibration problems of their own.

[captain awesome]

Yeah I'm thinking there are multiple offenders on this swap. I'm hoping if I swap out the trans mount for the STI, modify the stock shifter assembly to re-isolate the connection points, add in a Fluidampr or ATI crank damper, and do the two piece driveshaft it will be a considerably better environment. I know there are a lot of folks out there who might not care about most of this stuff but for those that do removing the Whiteline trans bushing made a massive impact so you may not need to go to such lengths. What I find tolerable has lessened over the years where before I would have just shrugged my shoulders and decided it wasn't bothersome enough to mess with. Age has a funny way of either softening you up or just coming to the realization that RACE parts aren't as cool in daily life as you think.



I just got back from the driveshaft shop with the shortened stock 2 piece. If I have time this evening I'll hopefully get a test drive in and report back. Will post up some pics as well.

[brzlegend]

The BMW dual clutch transmission swaps are taking alot of power from the turbo v8s and 6 cylinders but the little inline 4s are breaking the clutch baskets. You could get a dual mass from a honda diesel some have turned them to 9k with the BMW dct.

Captain is your clutch disc sprung?

[captain awesome]

Originally Posted by brzlegend

The BMW dual clutch transmission swaps are taking alot of power from the turbo v8s and 6 cylinders but the little inline 4s are breaking the clutch baskets. You could get a dual mass from a honda diesel some have turned them to 9k with the BMW dct.

Captain is your clutch disc sprung?

Clutch disc and pressure plate are stock Exedy parts for an 86. So yes it's a sprung disc. The Kpower flywheel is built to fit stock/aftermarket clutch/pressure plates.



DCT sounds awesome but I'd rather not mess with all that. I prefer the manual as it doesn't require tuning of the shifting and stuff I'm not really interested in tackling. Also I like getting to row through the gears. At some point I hope Jackson Racing follows through with a supercharger kit to fit the Kpower swap. Then I'll be looking to upgrade the clutch.

[Irace86.2.0]

I finished working out the vibration issues: it is the engine. It isn't the exhaust. It isn't the shifter. It isn't any rubbing points. It is simply the engine.

There are some noises that I have that are new from the old setup that aren't ideal. The sole, high-flow cat creates some drone at certain rpms, but overall, it isn't terrible, and it isn't there on the highway or in any way that can't be easily overcome with my stereo. There is some hollow noise that resonates on decel at certain rpms, which I can't tell if it is from the IC pipes, the exhaust, the skid plate or what, but it isn't loud enough, nor does it happen often enough to matter much, and again, it can be easily overcome with music, which I listen to loud most of the time.

There are several noises that I liked that are there still and possibly slightly louder, but not obnoxious. My Exedy Stage 1 clutch is sprung, but it does create some noise on decel. The Whiteline transmission bushing creates a mechanical friction noise that makes the transmission sound more mechanical, so I like that.

I don't think I am getting any driveshaft vibration. Such vibration would be there independent of rpms or accelerator input, but I really haven't detected anything consistently, but I'll keep checking. Overall, I don't think it is that.

It seems to be the engine at idle and in motion that is the problem, and I am certain it is mostly losing the balancing shafts in the oil pump. Certain conditions will cause an engine to vibrate. On a normal car, high-load low-rpm situations, low-load high-situations and on decel are times when an engine will typically vibrate more, so I think it is just slightly worse. Some of that could possibly get tuned out, and some of that could get smoother over time, as the Haltech makes adjustments, but I don't think there is really much else that can be done because race car. I drove the car around, and with the music on, the car seems to do fine. There seems to be less vibrations, so maybe the Haltech is figuring things out, and maybe the music is my best bandaid.

Here is what I did:

--I removed the under trays. Nothing appears to be touching them, and removing them did nothing to change the vibrations or noise.

--I detached the exhaust from the hanger. I turned on the car. It still had the same vibration.

--I felt the rod going to the bottom of the shifter. It was vibrating on the transmission end, but it was barely vibrating on the shifter end, and it became more obvious that the shifter is not transmitting anything to the car. It being hard mounted makes no difference at all, but I will say that the shifter on this setup is pretty awesome. I had the Perrin shift bushing, MTEC springs, and I had shortened the shifter, but this takes the feeling up a notch. It is lower, it is very solid feeling, and the shifts are very bolt action, which is great. I wouldn't want to change the shifter at all.

--Then I checked the chassis. The exhaust has about a centimeter gap. The AC lines has maybe 3-4mm from the head. The oil pan is about 1.5mm (confirmed with the feeler gauge) away from the steering rack, but it wasn't touching. The transmission is about 5-10mm away from the transmission tunnel at the closest point. I really couldn't find anything that is touching the chassis.

--I then decided to remove the transmission bushing. Instead of doing that, I just jacked up the transmission with some wood under it. At this point, the transmission mount was entirely removed, and the transmission was jacked up high enough that the gap by the oil pan and steering rack was 3-5mm, yet the vibration was still there, and I confirmed there was no chassis touching still, so I realized at this point, it was all the engine.

The vibrations pretty much disappear at 1400 rpms, and the resonance returns above or below. I could probably raise the rpms, but I took the car on a drive, and it just wasn't really that obnoxious with some music, and the shaking seems to smooth out some after cruising around. I think I can live with it for now.

[brzlegend]

Idle should be smooth with low vtc timing and a steady AFR around 14.5

[captain awesome]

I didn't have enough time to install the driveshaft so won't know for sure on that until this weekend.


I do agree there is probably quite a bit coming from the engine. Technically the steel flywheel is about 4 pounds less than the manual TSX so some added vibes can be attributed to that. Obviously the balance assembly removal with the stock oil pump is the real culprit. From my reading after Fluidampr being mentioned, I think that could help reduce that last little bit and also reduce bad harmonics higher in the rev range. I think that will be next on the list for me.

[Irace86.2.0]

Originally Posted by brzlegend

Idle should be smooth with low vtc timing and a steady AFR around 14.5

But it isn’t. It probably is the balancing shafts.

The solution might just be having a high idle like 1400.

[brzlegend]

Originally Posted by Irace86.2.0

But it isn’t. It probably is the balancing shafts.

The solution might just be having a high idle like 1400.

Without balance shafts it should be smooth into 3k 4k. What's your ign timing at idle? Afr? Vtc? You could unplug the vtc and see if that makes it smooth. Did you preload the tensioner on the chain?

[Irace86.2.0]

Originally Posted by brzlegend

Without balance shafts it should be smooth into 3k 4k. What's your ign timing at idle? Afr? Vtc? You could unplug the vtc and see if that makes it smooth. Did you preload the tensioner on the chain?

I don’t know. I’m at work, and plus, we have only done basic eTuning. We are waiting on a few things before dyno tuning. I’ve only seen the AFR around 14.5. At 1400 rpms it is solid. Why would that be?

I can’t remember if I preloaded the tensioner. I didn’t do it intentionally. I can’t remember if the pin got pulled by accident, or if I set it and then had to redo it, but I think something like that could have happened. Why? Do you think the chain skipped? I don’t really know how to preload it. I just lined up the chain and marks, applied tension to the left so nothing moved and pulled the pin. Did I do something bad?

I don’t think this is a problem with the chain. Everything there was really solid and in place. I guess it is always possible. Hopefully things will improve in time and with dyno tuning (more tuning, fuel pressure sensor and fuel pulse damper. If not then I’m sure the 1050cc injectors, on top of this swap kit, on top of the cool starts with E85, on top of losing the balancing shafts in the oil pump, on top of whatever else could be an issue, but if all else fails then I’ll recheck my chain. I’m not ready to start pulling off my valve cover at the moment.