Can we identify the problem with the KA?

[thekage]

Don't get me wrong I love the NA KA. But what exactly is the problem with it that reduces its effectivness to bolt ons? Is the reletivly low redline? The poor flow of the head? Any other ideas?

[:: orion ::]

Long stroke + not fully balanced crank = low redline.

No way around it except custom crank = $5000.

And it responds well to bolt-ons IMO....you can get from ~125rwhp STOCK to ~160rwhp with I/H/E, ECU, pulley, and cams. That's not bad for a 2.4 liter limited to ~7200rpm...

And anyway, a turbo kit is considered "bolt on"...and the KA responds VERY well to boost!!!

- Brian

[Xero]

horrific intake manifold, nuff said.

[skatanic28]

yeah i was making ~155rwhp at a bit under 6500 with a <12.0 AFR, without cams. im sure with a bit better tune and cams you could break into the 170's at redline.

the low revs and cam profiles kinda hurt you up top, where you see most n/a motors making lots of power.

[im two techno]

I put down 148 lbs or torque with 162 whp with I/H/E cams 248/248 pulley electric fan. I think the intake mani does suck but at lest its not t- body injected .... I think the KA likes mods i squeezed 30 more WHP to the wheels and thats not bad.
Modified by im two techno at 1:37 AM 4/6/2005

[:: orion ::]

Intake mani isn't the best...but for a motor that can't rev much higher than ~7k...a better one won't really help that much, IMO.

If we had ~8500rpm to play with, and cams to back it up...intake manifold would need to be changed to make good power.

But with any of the current cam offerings, and the limited redline...stock isn't too bad.

- Brian

[initial_d_s14]

isnt there a way that you can, i guess you can say, "custom" make an intake manifold, you know to where the flow isnt so long? i know you can do this but has anyone on here done it. i was wanting to do it to my S13, but i was kinda sceptical about the results and if it was worth it.

[skydragoness]

I thought the low-revs sucked on my car until I drove a friends SE-R Spec V... (they are rev-happy regardless though)

[corn322]

this one guy on here a while back was talking about making one. I havn't heard about it in a while though.

[thekage]

There is a guy selling custom intake manis in the for sale section... 250.

What can we do to increase the redline to make more power?

[USDM240]

There is a guy selling custom intake manis in the for sale section... 250.

What can we do to increase the redline to make more power?

custom chipped ECU.

[im two techno]

You can take an Altima intake and cut it short hone it out and make a better tank. the Altima intake has much strater runners than the 240 does.

[coolcloo1019]

i made 141 hp and 141 torque with only catback exhaust and test pipe... so i don't know ... guess it all depends.

[Bigvinnie]

I have a thread in the club240 forums that will solve all of your problems. Maybe some of you are apart of these forums and have red the thread already.http://www.club240.com/forums/...19485

[:: orion ::]

BigVinnie...what's so ground-breaking in that thread?

Say you decide to knife-edge and balance the crank...We still have 80% the same problem...long stroke. You can alleviate some of the balance problems, but cannot reduce the super-high pistons speeds that the KA generates at ~8000rpm (upwards of 5000ft/min!!!!!).

The safe limit is about ~4000ft/min...which the KA already exceeds at ~6500 with a stock crank (96mm stoke, or 3.77")!!!

To run 5000ft/min pistons speeds, you better have something better than stock rods...or else you'll see one exit the block in short time.

- Brian

[thekage]

Vinnie.. just read that thread.. took the last 3 hours.Wow. I have some questions for you man.

[:: orion ::]

Hehehe...I just took another look to see if I missed anything...

...and I noticed that someone actually posted the same info I did (about piston speed) with a link to the "Ask Sarah" article in "Nissan Performance Magazine" ... and it was ignored.

...and I also noticed that the best info in that thread were all the corrections made by "DeviousKA".

So I wanted to bring it up again...what do you plan to do about the EXCESSIVE piston speeds that will be generated by running such high RPM? That would be fine for a race-only motor, that was not expected to last...but not a street motor that's expected to last even 20,000 miles.

- Brian

[Bigvinnie]

Brian you are a pretty smart guy, but me personally I am into bore and stroke. I don't mind the rev and 2.4litre's it is a pretty strong vacuum/ air pump. Honestly to correct that problem you would have to do one of 2 option's. Destroke the engine for smaller displacement.Install sleeves into the KA and drop the size to 2.2 or lower.Or get a NAPS-z 2.0 or 2.2litre block. You can get a NAPS-z block for about $300 at a wrecking yard. KA heads,transmissions, and pans bolt right up to NAPS-z blocks.

Then go with L20pistons, KA "sohc" rods forged of course. Or get a NAPS-Z forged kit for 2.0 or 2.2 litre, but then you will have to mill the KA head to get higher compression, because of the dish volume of the NAPS-z piston's.Oh and I can't forget the install of CA18det titanium retainers and springs.Another application possibly needed for such high rev would be a dry sump oil system.Is that the responce you were looking for?

Modified by Bigvinnie at 1:48 PM 4/7/2005
Modified by Bigvinnie at 1:54 PM 4/7/2005

[:: orion ::]

...but me personally I am into bore and stroke. I don't mind the rev and 2.4litre's it is a pretty strong vacuum/ air pump.

...

Is that the responce you were looking for?

Bore and stroke is fine...it just that with the KA's stock stroke, you simply CANNOT run +8000rpm for extended periods with STOCK rods...no matter how well you prep the crank...and no one addressed that in the other forum's thread.

Someone brought it up, but it wasn't given a single reply...everyone just looked over it.

They were all over the crankshaft balance issue...which is a concern...but not the whole problem.

...

And the response I was looking for was how you were going to keep your stock rods from snapping at rediculous piston speeds...which you indicate now that you'd look into forged rods (possibly with shorter stroke)...which is fine...

...but it was just never brought up as a potential problem. I was just asking why it wasn't given due consideration.

- Brian

[Bigvinnie]

I see my bad Brian. I thought that it would be typical when purchasing the piston's that you would also have to get the forged rods also as a kit. I guess that is why it wasn't completely explained in my thread. I admit it should be more indepth, I do have a problem bringing out "ALL" the facts, but I do try to be as indepth as I can in a post. Sorry.If you guy's are looking for forged rods and pistons Topline sells them the cheapest for the KA. Or atleast that is what I have seen.Typically I have seen personally a KA with forged internals, 11.3.1 compression at 2.4 litres redline almost at 8300RPM, that is MASSIVE potential if the KA were to go turbo, it would put it on the level if not better than an RB."But honestly if you were going to go turbo you would have to drop the compression to about 9.5"....I've noticed with the KA if you make the the piston mass smaller "destroke/decrease displacement" the redline becomes much higher. Lets say for example the displacement is 2.2 now the KA can redline to lets say about 8600RPM. Then again decrease the displacement to lets say about 2.0 litre's now you have a KA that can possibly high rev to about 8900RPM. That is MASSIVE potential for a 4banger with a stroker type crank.In many way's it reminds me of the CA engine of the mid 80's...

Modified by Bigvinnie at 7:16 PM 4/7/2005

Modified by Bigvinnie at 7:18 PM 4/7/2005

Modified by Bigvinnie at 7:33 PM 4/7/2005
Modified by Bigvinnie at 7:35 PM 4/7/2005