KA vs SR: From the a racing viewpoint?

[Mangudai]

KA24de

• Bore × Stroke: 89.0 × 96.0 mm (3.50393 in. x 3.77952 in.)
• Displacement: 2.4L
• Max power: 155 hp @ 5200 rpm
• Max torque: 160 ft·lb @ 4200 rpm
• Valve Configuration: DOHC, 16 valves
• Compression ratio: 9.8:1, 9.5:1, 9.3:1

SR20DE

• Bore X Stroke: 86.0 x 86.0 mm
• Displacement: 2.0L
• Max power: 140hp @ 7200 rpm*
• Max torque: 138 ft*
• Valve Configuration: DOHC, 16 valves·lb @*
• Compression: 9.5:1*

I put asterisks after the things that were conflicting with what I searched and what im not sure of. I'm not asking what engine is the most cost effect or which holds more hp with stock internals. But from a racing perspective, which is the superior engine?

A few things that would matter when considering any engine

Weight
Hp/Tq numbers
Powerband
Aftermarket (parts etc)
Durability
Reliability


Lets say both of these engine are in a say..base model 89 S13 if it matters. After this, consider if both engines were turboed. What changes?



I realize this has been probably talking about but try searching ka vs sr nothing comes up because of the short words. I had a hard time trying to figure out alternatives and most all the threads ive seen in the past asked which is cheaper to boost etc.


Random thougts:

Will a KA always have more torque than an SR20? Is it inherent in the KA's design that they leak oil. Are they both as easy to work on? Im not throwing these things out there as fact but to spark conversation.


But like I said, this has probably been done before..

[SleepR 240sx]

Lets say both of these engine are in a say..base model 89 S13 if it matters. After this, consider if both engines were turboed. What changes?



I realize this has been probably talking about but try searching ka vs sr nothing comes up because of the short words. I had a hard time trying to figure out alternatives and most all the threads ive seen in the past asked which is cheaper to boost etc.


Random thougts:

Will a KA always have more torque than an SR20? Is it inherent in the KA's design that they leak oil. Are they both as easy to work on? Im not throwing these things out there as fact but to spark conversation.


But like I said, this has probably been done before..

It all depends on the setup you are running....with the same turbo the results will be very different on the two motors because they are two DIFFERENT motors. Asking if the KA will always have more torque is like asking if the SR will always be more rev happy. On either one it's not a given, it all depends on the setup your running. If you want to find the pros and cons of the motors simply search through the KA and SR FAQ guides here in the tech section.

[fliprayzin240sx]

You can start by looking up dyno graph for either engine. Most SRs over 400-450hp will have a hard time making anything more than 350 ft lbs of torque due to the smaller displacement. I've seen KA-T torque numbers keep up with HP till till 450.

But since youre asking between NA SR and a KA. My question would be, why bother putting in an SR20DE in a 240 when you already have a KA in it? Why do more work if you're just gonna turbo it anyways?

[Mangudai]

If went sr20 it would be the det variation, I just figured comparing engines in their simpliest form would make more sense.

[SochBAT]

If you want Turbo, SR. Cheaper power for the money.

KA if you really like DIY power. and response. Then again, i am biased.

[Mangudai]

Originally Posted by Soooshi

If you want Turbo, SR. Cheaper power for the money.

KA if you really like DIY power. and response. Then again, i am biased.

I know, but im wanting to know which of the two is superior from a road racing view

[sac]

Originally Posted by Mangudai

I know, but im wanting to know which of the two is superior from a road racing view

IMO i would go with the KA because you dont have to buy a 2k engine. You could use that 2k to go towards a full rebuild, better turbo setup, areodynamics, safer car, etc.. However if i had the sr i wouldnt change it out for the ka.

But your comparing two engines that are very different. One has better top end, while the other has better low end.

[SochBAT]

If you've got time to learn, rock your stock KA. You can push it to its limits and beat it like a whore. if it blows, they're a dime a dozen. Highly responsive and really snappy (if you have the right mods).

I was running shitty parts on my SOHC but it has snappy and zippy as hell. Get a crank pulley, a nice exhaust (no fart cans) and good suspension work and you're golden. I had 2.25" piping with a shithole Raptor exhaust, subframe bushings, a crank pulley, ST sways and shocks n springs and it did wonders. Its all in what you plan to do.

[S14DB]

2.4L will always have more tq then a 2.0L.


But, really. This all depends on the rules for your class.

[fliprayzin240sx]

Sorry, you confused the fuck out of me since you put out spec for NA SR20DE.

Stock SR20DETs are rated 210hp iirc. Swapped in, they usually put down around 180whp ballpark with stock boost. Most KAs put down roughly 120-130whp. Personally, the SR got 3 advantage over the KA. Its already turbo, low compression piston and heavy aftermarket support.

[nani]

I think the KA has a better head design and could probably withstand more punishment...

[Nikeboy355]

This all depends on what type of racing you want to do, how much power you want, and what your rebuild budget is...

I personally prefer the KA overall because:
1. Cast iron block
2. Larger displacement
3. Head flows the same as an SR
4. Larger valves
5. No hydraulic lifters
6. Larger bearing surface

The only downside to the design would be that the crankshaft was not counter weight balanced like the SR...

The KA weighs 50 pounds more than the SR but sits slightly lower and farther back than the SR... The KA and SR have the same duration of power band but the SRs redline is about 1000 higher thant the KA...

Other than running a bone stock SR setup in my car I would run KAs...
I have plenty of videos of my car running the stock NA KAs...

www.YouTube.com/nitinj355

[LongGrain]

comparing a KA to an NA SR is stupid

in all fairness, yea i guess thats the "fair" way to compare them

but honestly, who swaps in an NA SR? i know a few people do, but i dont even think ive ever seen NA SR swaps for sale ANYWHERE...

[Bigsyke]

no replacement for displacement.


That is all

[fliprayzin240sx]

I actually like KA-Ts, that was the route I was planning on doing a long time ago until my tranny decides to take a dump. Finding a OBDII tranny for a 97 S14 is next to impossible and it was gonna cost me $1800 to rebuild it. Why rebuild my tranny when I can get an SR swap fro $1300? Thats how I ended up with an SR.

Anyways, Nikeboy pretty much hit on the head the advantage of the KA. The only thing is that most KAs are higher mileage engines. Its rare to find a KA with less than 120K miles on it. I wouldnt wanna boost it without rebuilding it first. For as much money you'd spend to get an SR swap done, you can build a KA bottom end up to handle the boost and a DIY turbo kit that could potentiallly beat the snot out of a stock SR.

[S14DB]

SO, We're just bench racing here right?

[Mangudai]

Originally Posted by fliprayzin240sx

I actually like KA-Ts, that was the route I was planning on doing a long time ago until my tranny decides to take a dump. Finding a OBDII tranny for a 97 S14 is next to impossible and it was gonna cost me $1800 to rebuild it. Why rebuild my tranny when I can get an SR swap fro $1300? Thats how I ended up with an SR.

Anyways, Nikeboy pretty much hit on the head the advantage of the KA. The only thing is that most KAs are higher mileage engines. Its rare to find a KA with less than 120K miles on it. I wouldnt wanna boost it without rebuilding it first. For as much money you'd spend to get an SR swap done, you can build a KA bottom end up to handle the boost and a DIY turbo kit that could potentiallly beat the snot out of a stock SR.

I like how you guys explained your views, this is exactly what im wanting to know. I have a '96 @ 104k miles. I totally forgot about the OBDII issue when it comes to the tranny.(im slush for now)

[S14DB]

Dang I have a 98 KA and 98 tranny with 68k on them. sucks to be you guys.

So, what "racing" are you planing on doing? What are the rules and regulations on engines in your class?

[Mangudai]

I will take lessons first but I would like to do HPDE basically

[fliprayzin240sx]

Originally Posted by Mangudai

I will take lessons first but I would like to do HPDE basically

Lessons for HPDE?!?! You drive as fast as you can without eating cones...not that hard. The hardest part is not running off the course thru the cone parade...

Besides, if thats all you wanna do, Id invest the money on suspension and R-compound tires. That should be all you need to learn first. Once you get comfortable, thats when you start adding power into your car in order to start cutting your times down.

[S14DB]

Originally Posted by Mangudai

I will take lessons first but I would like to do HPDE basically

Well I would find out the rules and classes of the racing you plan on doing.

I know around here a SR swap or turbocharging the KA puts you into an insane class.

Suspension and breaking upgrades will show you more gains in HPDE. Hell, tires are the most important.

[Mangudai]

Makes sense, thanks.

[SochBAT]

Originally Posted by S14DB

I know around here a SR swap or turbocharging the KA puts you into an insane class.

It throws you into the same league as SC'd Vettes and retardedly built cars.

If you like that kinda challenge, shoot for gold.

If you want a more reasonable way, build up suspension and tires as stated before.

[aNskY]

Originally Posted by Bigsyke

no replacement for displacement.

except for technology...

[JaeTea]

Originally Posted by aNskY

except for technology...

good point.

[BigVinnie]

Lets start off with the KA's low points since thats where people will argue over what engine is better (KA VS. SR debate).

Well after talking with brian crower at Formula drift round 6 about his stroker kits, Sales didn't do so good (or he didn't sell as many as he thought he would of expected too). This isn't because the KA is a bad engine. It's more of the fact that people that own this USDM engineered, JDM built engine, don't support the aftermarket performance aspect of it. KA has been given a bad rep for several reasons.....
It's a smog emissions engine, this makes tuning for realistic performance enhancing improvements for HP are harder than it would be for the SR20 FR engine which isn't smog compliant....
Smog emission devices kills and hinders performance. The KA's long stroke and mild compression ratio was designed strictly for smog emissions, just as the NAPSZ and Lseries engines had been, this is old engineering that Nissan has used for over 30+ years since the mid 1960's.
Look at several restrictive devices that the KA uses......
A small G60 MAF for OBD 1 hinders it's performance under load. There arent many changes to timing under load that you can make with that MAF and even most people that go turbo charged throw the G60 away, over a G70, N60, E60, or N62....
It's apparent that SCV's are a smog device on OBD 1 KA's and hinder overall top end performance, you don't find SCV's on sr do you... (sarcasim).
Even the Sr head barely out flows the KA head, again this was a means of having realiable smog emissions.
Look at hindered performance from the OBD2 aspect.......
If you take emissions devices off of OBD2 KA's, the engine loses power, since not reading voltage or OHMs from any of the emission sensors will just throw the ecu into a limp pig rich mode, and throw the K value and CAS value so far off the chart, ignition timing would be beyond retarded.....
Theres no hope for the KA as long as it uses it's emission control devices, thats how it was made, inherently by design....

Other than those problems the KA is a great engine if you can get past the emissions problems....

To get back on point with Brian crowers kit.........
With his new piston, rods, and crank kit the KA with stock valve train will redline and make peak power to 8500RPM...... With titanium retainers and valves it revs and makes power past 9000RPM..... So why with this great kit is it not being sold abundantly to the masses????

1.) people aren't educated enough to understand the perfromance aspects and gains from this kit....
2.) Most people aren't savy or educated enough to work around the smog emissions aspects.
3.) If you own a KA it's simply for the fact that it's easy and cheap from a local junk yard.....
4.) As a race prepped engine with people that do under stand curb weight ratio's the KA is a heavy CAST Iron Block... But if you look past how heavy it is it makes more peak torque than an aluminum block SR...

After Brian and I were done talking we both came to the conlcusion..
Yes it's a truck engine, it's seen as a truck engine... But if you get past that aspect and know how to build an engine, than you have something better than a truck engine....

Smaller displacement is an uphill battle in the world of natural aspirated tuning, especially in the performance world.... If you look at any manufacturer to date over the engines they have produced, engine displacement, and compression ratio's have increased......

Reason being is that the BTU of fuel over the last 10 years has become less than what it was, which has lowered power output. (This isn't an advantage if I were to be that guy that had smaller displacement.)

Now as much crap as I talk about the KA, I wouldn't give it up for anything in the world.... Quite possibly because I've figured out something most of you haven't. Or for those that just chose to believe what you feel is right for you as far as goals for achieving the power and response some one wants to deliver from "THEIR" engine.

[sunnys14]

Originally Posted by fliprayzin240sx

I actually like KA-Ts, that was the route I was planning on doing a long time ago until my tranny decides to take a dump. Finding a OBDII tranny for a 97 S14 is next to impossible and it was gonna cost me $1800 to rebuild it. Why rebuild my tranny when I can get an SR swap fro $1300? Thats how I ended up with an SR.

What is the difference between from the OBDII tranny compared to OBDI??? I never knew there was a difference besides the crankshaft position sensor ontop of the tranny bellhousing.

[Mangudai]

First off let me say that was a great post, lots of insight.

Originally Posted by BigVinnie

It's a smog emissions engine, this makes tuning for realistic performance enhancing improvements for HP are harder than it would be for the SR20 FR engine which isn't smog compliant....
Smog emission devices kills and hinders performance. The KA's long stroke and mild compression ratio was designed strictly for smog emissions, just as the NAPSZ and Lseries engines had been, this is old engineering that Nissan has used for over 30+ years since the mid 1960's.
Look at several restrictive devices that the KA uses......
A small G60 MAF for OBD 1 hinders it's performance under load. There arent many changes to timing under load that you can make with that MAF and even most people that go turbo charged throw the G60 away, over a G70, N60, E60, or N62....
It's apparent that SCV's are a smog device on OBD 1 KA's and hinder overall top end performance, you don't find SCV's on sr do you... (sarcasim).
Even the Sr head barely out flows the KA head, again this was a means of having realiable smog emissions.
Look at hindered performance from the OBD2 aspect.......
If you take emissions devices off of OBD2 KA's, the engine loses power, since not reading voltage or OHMs from any of the emission sensors will just throw the ecu into a limp pig rich mode, and throw the K value and CAS value so far off the chart, ignition timing would be beyond retarded.....
Theres no hope for the KA as long as it uses it's emission control devices, thats how it was made, inherently by design....

Question specifically for the OBDII engines, its expensive but couldn't you avoid the emission issues if you pull all that stuff off and went standalone? I'm not sure so im asking.

Originally Posted by BigVinnie

Other than those problems the KA is a great engine if you can get past the emissions problems....

To get back on point with Brian crowers kit.........
With his new piston, rods, and crank kit the KA with stock valve train will redline and make peak power to 8500RPM...... With titanium retainers and valves it revs and makes power past 9000RPM..... So why with this great kit is it not being sold abundantly to the masses????

1.) people aren't educated enough to understand the perfromance aspects and gains from this kit....
2.) Most people aren't savy or educated enough to work around the smog emissions aspects.
3.) If you own a KA it's simply for the fact that it's easy and cheap from a local junk yard.....
4.) As a race prepped engine with people that do under stand curb weight ratio's the KA is a heavy CAST Iron Block... But if you look past how heavy it is it makes more peak torque than an aluminum block SR...

Wow..I've never heard this.. and unfortunately as you hinted at most people with cars this old are cheap asses which is really unfortunate.

Originally Posted by BigVinnie

Reason being is that the BTU of fuel over the last 10 years has become less than what it was, which has lowered power output.

Did not know that. Interesting.

[Pblesh85]

Im not sure if this is off topic or not, but here goes.

Would it be cheaper to buy an s14 sr and build it to 350~400whp with torque close to that number ?

Or would it be cheaper to do a ka-t with the same hp/tq numbers ?

Reliability is a big factor and emissions is to be considered as well.

Its more of a bang for your buck and total cost question. I know the motors are only as good as they are built and tuned. Im just currious which is cheaper to build and use for a daily driver.

[Pblesh85]

Also if you want to go ka-t what engine management options do you have, and then can you pass emissions with any of them ?

Can you even pass emissions with a map sensor set-up ?