KA vs. SR could get ugly

[ADAMHU]

lets keep in mind....those engines were only built due to one thing.....

RULES....

if you gave race builders carte blanche to build a race car...with no rules...i 100% will tell you you would not see any small 4cyl engines...they would all be forced induction big blocks....

go in some road race series where you have v8's running with turbo 4's..... on small tracks you might be able to keep up...give those v8's some room to run...and they will walk all over you.....

the KA can be built up, and when it is..it is going to beat the SR in every way....

Bill, bill, bill; please read the past few pages. This has already been discussed. Read all my posts and dyno plots. Oh, and when (or should I say if:rolleyes ) I finish with my car, I will drive to Tampa (I live in south FL) and meet you at whatever local drag strip you have there...if you accept the challenge of course:) It'll be a friendly challenge. I like 240's and it'll be fun to compare.

ADAMHU, this is going to be fun! First of all, your KA needs to have a good rod ratio...because your rods are so freaking long! If it didn't, you'd have a 4 grand redline or a lot of bent rods! Tell me, what's the purpose of a good rod ratio when you can't even take advantage of it?

And about your 5.7ltr V8 comment...I'll take the 1.5ltr turbo V8 from the F1 cars of the early 80's! You can keep your displacement.

[Dori Dori]

I'm sorry, you have not made one good point (well, almost with the rod ratios) and you continue to act like a child. We aren't comparing 4cly to 8, we are comparing 4cly to 4cly.:thinker

:wavey bye now, next caller...

[ADAMHU]

[Bill]

Bill, Bill, Bill; Oh, and when (or should I say if:rolleyes ) I finish with my car, I will drive to Tampa (I live in south FL) and meet you at whatever local drag strip you have there...if you accept the challenge of course:) It'll be a friendly challenge. I like 240's and it'll be fun to compare.

Anytime you want!

If you dont mind me asking, what is going to be done to your car?

[ADAMHU]

unless you have some magic gear box, and are able to hold that SR from 6700-7500rpm all the time at the track...the KA is gonna be the stronger motor.....

do you see all that space under the KA motor!!! that is space where the ka will be pulling on the SR

[ADAMHU]

how is discussing things acting like a child?

i keep bringing up v8's since it seems you do not appear to know what affect displacement has on performance..

I'm sorry, you have not made one good point (well, almost with the rod ratios) and you continue to act like a child. We aren't comparing 4cly to 8, we are comparing 4cly to 4cly.:thinker

:wavey bye now, next caller...

[Dori Dori]

Bill, nothing huge...probably a K3T kit from Blitz; or maybe the PE 1820 kit. I want something different and both kits have their ups and downs. The PE kit has a BB turbo, but the Blitz kit has a tubular manifold. Everybody runs garrett's and I don't like IHI. I don't want to go huge, but I'm not looking for a super low-end (who does with a turbo'd car anyway)... I'm hoping for 350-375whp at low boost settings and 400-425whp at high boost (pump gas). I don't want to reduce compression (by means of gasket), but I may have to. Also, I'm going to try to run some sort of piggy-back ecu (haven't decided which one yet) and a boost controller. We'll see how that plays out though. I'm going for all around fun.

[ADAMHU]

so where is your comeback now....the chart is posted with both engines overlayed.....

what do you have to say...

[WDRacing]

ha ha ha... lol....

I love moderators with big mouths.

n

btw - you got a website or something with your racing accomplishments?

Heh...I thought you would like that post. I must admit I stole it from the Supra forums from a few years back. There was big GTR vs. MKIV debate going on.

Big mouth...yep...I'm sure I'll get talking to eventually.

No web page...sorry. I've been stuck with dial up for the last 6 years.

The only racing experience I have is some minimal track time when I lived in FL and pure street racing over here in Japan.

........................................................................................................

Looks like the end of this thread is starting to get some more deliberation. Being a fan of displacement myself makes me lean towards the KA. The revs can be increased, its just that no one has done it. If so, then I haven't talked with them. My car will have a rev limit set to 7200 with optimal shifting right around 7000. But I'll have to wait and see what the dyno barfs up to make any final desiscions.

That would put my KA far beyond most SR's. Peak HP is for Honda's. I can say that, I've owned 2 and hated both. Give me a torque curve and I'll be happy.

WD

[Nils]

Heh...I thought you would like that post. I must admit I stole it from the Supra forums from a few years back. There was big GTR vs. MKIV debate going on.

Big mouth...yep...I'm sure I'll get talking to eventually.

No web page...sorry. I've been stuck with dial up for the last 6 years.

The only racing experience I have is some minimal track time when I lived in FL and pure street racing over here in Japan.

........................................................................................................

Looks like the end of this thread .......

WD

ha ha... lol... I know what you mean, alot of supra owners call Supraforums "moronforums" =) alot of **** talkers on there.

...ouch, dial up...

I am assuming you drag race?... you should try road racing sometime =)

take care,nils

[Dori Dori]

so where is your comeback now....the chart is posted with both engines overlayed.....

what do you have to say...

Please, once again, this has already been discussed. Go back in this thread to where I started posting and READ!

*sigh* This is getting redundant and foolish now...

WD, did you at least get what you wanted?

[C-Kwik]

Engine comparisons of the heavily modified variety are hard to discuss objectively. Other than the fact that the KA and SR are both 4-stroke 4-cylinder Nissan Motors that came in the S13 and S14, they are quite different. Most of what I see in the this thread are subjective thoughts, and while all valid, are based on each person's own circumstance and desires. Different motors will behave differently at different power levels. One motor may be more suited to a certain type of racing or driving than the other. Sometimes even the rules of racing can have an effect on what motor is better suited for that car. Cost of course is a large factor as well. For those of you that make arguments about "cost not being a factor", then that would really draw out more inconclusion since I could just seriously reengineer each motor and the potential for each could be endless. And as Nils posted somewhere earlier, each motor must have the same mods. But that gets tricky as well. There was a dyno comparison posted on here between a 15 psi KA and SR. But there were differences in the mods. Someone else posted an SR running a T3/T4, but that still doesn't tell us the whole story. Turbos have different trims and A/R's. There could be differences in I/C efficiencies. Manifold design differences can affect power. You could go as far as comparing an SR vs KA where the major parts are similar on both and still not have a very good comparison. Why? Because if you were to use the exact same turbo, it may not be as good for one motor as it is for the other. To build a good turbo motor, you must consider the goals, and how well the turbo is matched to the motor for that goal. It would be very difficult to come up with any kind of an objective answer to this debate.

An easier argument would be to compare the same motor built in different ways, but even that could be hard. Take the Hondas out there that are running sub 10 second 1/4 miles. There are really only a few engine builders among them, but each builder has their own way of making power. One may look to higher RPM's while the other looks to just making more torque with less RPM's. But the HP remains similar so the cars still run close 1/4 mile times.

Lets now take a JGTC Supra as an example. They don't use the 2JZ-GTE motors in them. They may have at one time if I have heard correctly, but the top Supras are the ones running 4 cylinder motors(I believe the same one as the MR-2 and All-trac Celica). They are faster from what I hear. My speculation is that the Supra is weighing in at more than the minimum weight and using the 4-banger helps to reduce weight. The JGTC has HP limits, not engine size limits. So for the purposes of that series, the smaller, lighter 4-banger has become the better choice over the almighty 2JZ-GTE.

Now if you wanna argue that "A" Motor is better than "B" Motor for this purpose because blah blah blah, then it's a more valid point since you are making a subjective point with objective circumstances.

Adam brought in a good point about the transmission gearing. While I will not say if his point is right about the KA or SR, it is an objective circumstance to consider. Does Greaser's motor match the transmission better or does Dennis's motor match the transmission better. But that doesn't speak for every KA and SR. Only the comparison between their motors. You could easliy throw a big wrench in that topic by perhaps using an S15 transmission on Greaser's car. I think arguing points this way could prove to be quite productive, but the whole general SR vs KA debate is about the biggest dead horse in the 240 world.

[syka24et]

KAt vs. SRdet dyno comparison

-demetrius

This was the graph i was referring to I didn't see your could you post or your point. Must have missed it.

[WDRacing]

ha ha... lol... I know what you mean, alot of supra owners call Supraforums "moronforums" =) alot of **** talkers on there.

...ouch, dial up...

I am assuming you drag race?... you should try road racing sometime =)

take care,nils

I have based all my attention on drag specific vehicles. All three of my last Skylines were built for drag only. But I just parted out my last one.

My new ride is the Miata...probably the funnest car I've ever driven next to the MR2 turbo. I'm building this one for the island twisties. Its alot different driving a car with no turbo lag.

WD

[syka24et]

:rolleyez ka=:toilet

Dori what was your post about no one in this thread said, my precious ka, or whatever. well look at that.



Anyway the jwt crap thing,like I said was just an opinion. You have an opinion too, right so what makes mine wrong. Personally my situation calls for a standalone. My vain point is that the ka is not trash and can make good power that's it. I do not see why you swear I was making references to you.

[JamesT43]

Just thought that I would toss out one point in favor of the KA... (although I, myself am not taking a side in the debait)

If the car that is being built will see any SCCA racing, a KA24-DET may actually be in a lower class with the same amount of power. Swapping an SR20-DET engine into the car *should* (correct me if I am wrong) automatically plop you into the "Modified" class, where you will most likely be torn to shreds with a 240sx.

For those of you who don't know, the modified class is the highest class and recieves the least handicap on the PAX index. It is more or less the "anything goes" category.

[ADAMHU]

i guess you just don't see what is happening on that chart that is overlayed...unless you get some transmission that can hold the power in that small rpm range,...the SR is going to lose...in whatever racing you want to do...period

now...lets just say we do buid up a mega sr and a mega ka...

lets say...that we use the same turbos, and the same intercoolers...and the same internals....and lets say we are able to get the SR to rev to 9000rpm...and since the KA is harder to rev...lets give it 7500rpm...both heads can be made to flow the same...lets say we really put some money into them and got a 95% volumetric efficiency...

THE ONLY ADVANTAGE THE SR HAS is its higher rev range..thats it....

(KA) 142x7500x0.5x 95% /1728=292cfm(SR) 118x8000x0.5x 95%/1728=259cfm

we would boost on top of this of course...these are NA figures

i am not sure if you can see the relationship that is starting to form here...there are 3 functions in a engine that can increase its flow...displacement and rpm and VE....so unless you increase those far and above the KA you are fighting a losing battle....

ok lets say for some crazy reason..we could get the SR to rev to 9000rpm..

SR) 118x9000x0.5x 95%/1728=291 cfm

the above was already shown to you in the dyno overlays....so....

unless you can get the SR to significantly out rev the KA, and get a transmission that optimises the SR's power for a very small area...the KA is superior...

now....for the street...i would say..the SR is smoother..yes....but if we are talking about performance...the KA wins...

Please, once again, this has already been discussed. Go back in this thread to where I started posting and READ!

*sigh* This is getting redundant and foolish now...

WD, did you at least get what you wanted?

[JamesT43]

From a purely numerical standpoint, the KA engine is shown to produce a higher CFM solely because of it's increased displacement.

This is a good point, although it does not take into account any other difference between the engines. If the only true rating of performance is found with the CFM, power of an engine should be directly proportional to the displacement.

While power IS in fact directly proportional to displacement in theory, we are discussing wether that stands in actual practice.

Dissapointingly for domestic car lovers, alcohol distributors, fat girls, and unfortunately KA-T tuners, displacement is not always the answer.

[ADAMHU]

ok...show me why i am wrong...what is so magically different about the SR .....?

convince me....prove it to me....you just don't seem to get how important displacement is....there are 3 factors...RPM, displacement and VE....so unless you can overpower the other engine enough in catagories you cannot win....

the KA wins in displacement, can be equal in VE, and the SR wins in rpm....but not enough...if you could get the SR to race at 10000rpm...then i would say...yeah...thats a better motor..cause you can use the gearing of the car to your ADVANTAGE...but thats not the case....as shown on that overlayed dyno chart....there is just not enough peak RPM advantage over the KA for the SR to be superior...

or prove to me that a V8 is not better than a i4

lets do up a v8 lets do a 350...lets say we do some race heads..get a VE of 90%, and with good internals can get it up to 8000rpm.....

350x8000x0.5x90%/1728=729cfm

you tell me if you were building a race car..which motor you are going to pick....

there is no magic to this......

[I H8 UR DSM]

why not do the Quad4 vs a v8 ; )

sr20de vs. ka24de, give the nod to the ka, no?

sr20de+t vs. ka24de+t, i give the nod to the ka also....i think the comparissons need some working on.....

2jz still my pick ; )

[I H8 UR DSM]

or we can ask Paul, because CA18det OWNS ALL, right? ; )

[Movingviolation240]

Have you seen a intake manifold that makes almost 15 hp at 5000 rpms. Well greddy makes one for the sr.

well, I can make a custom rail that will have better results for about $200 less for a KA-T so no thanks

Why would someone want to buy a custom fuel rail which might be good, or might suck, when they can buy an hks they know works good, get injectors that drop in with mods and have a warranty?

the stock SR fuel rail sucks, the number 4 cylinder will run lean at extended WOT (ask enthlapy what happened to his motor) and then you get to experience the joy of rebuilding a motor that no machine shop has ever seen in this country. There is a reason that almost nobody runs sidefeed injectors on their racecars... they suck. Not to meniton that for the price of 4 sidefeed injectors I could have 4 750cc squirters, a custom rail, and adjustable fuel pressure regulator and still be saving $50.

There is NO replacement for displacement, EVER, end of story. What's going to make more HP a 2.0 16V motor or an 8.0 32V motor if both are running 30psi of boost and a 200 shot? If displacement dosn't matter why do they limit the size of the motor's in Indycar, WRC, CART, hell even Nascar? Face it size matters I guess some of you just have a hard time admiting that to yourself.

PaulOrlando, FL

[JamesT43]

Do not confuse my previous post with an argument against the importance of displacement in an engine, or against the KA engine in particular. I was merely saying that there is more to power than CFM.

[ADAMHU]

if you don't have the air..you can't burn the fuel..

Do not confuse my previous post with an argument against the importance of displacement in an engine, or against the KA engine in particular. I was merely saying that there is more to power than CFM.

[Movingviolation240]

Next, I'd like to bring up a fact. The enjuku dyno chart that I posted up does not run a stand alone, does not have a bb turbo, and has completely stock internals. Just like the KA that I posted up that makes less power and torque. The mods are exactly the same on both cars with the exception of where they got their ECU's reprogrammed.

Ken spent over 8hrs on a dyno getting that ECU tunned perfectly, so it's not quite 'drop in'

Ken dosn't quite have as much work as Chris, but he dosn't exactly have a 'stock' SR either, lots of little things he's done to it (bolt on's) And at 15psi most of the work Chris did (pistons, rods, crank work ect) isn't required. All you need is good management and you can have big numbers with either motor.

Above 20psi is where the 'fun' starts

[Movingviolation240]

or we can ask Paul, because CA18det OWNS ALL, right? ; )

actually I sold my CA, got an S14 and I think I'm gonna go KAT on this one. Had to try somthing different, the 9,000rpm motorcycle motor was fun, now I want to feel 6500rpm and 450ft lbs

Paul

[C-Kwik]

[quote=" ADAMHU

THE ONLY ADVANTAGE THE SR HAS is its higher rev range..thats it....

(KA) 142x7500x0.5x 95% /1728=292cfm(SR) 118x8000x0.5x 95%/1728=259cfm[/quote]

The problem with your statement here is that CFM alone is not indicative of the actual HP made. If a motor is able to rev higher, it can take advantage of gearing and put the same torque after the gears with proportionately less torque. That is why for a given amount of torque, more HP is made if you rev higher.

As an example, an F1 motor makes some 700+ HP at some 18,000 or so RPM. If we assumed 700 HP at 18,000 RPM, then the motor is actually making only 204 lb-ft of torque at 18,000 RPM. I would suspect the peak torque is only marginally higher. Revving higher can be a huge advangtage.

And 7500 RPM out of a KA is cutting it real close and according to JWT is when you start to get vibration out of the bottom end. And most NASPORT KA builders will tell you that it will take much more than a simple balance job to pull more RPM's out of the KA.

[Movingviolation240]

actually if I remember hearing right F-1 motor's make less torque than that, it's really REALLY a low number. They have to run some crazy gearsets to make it all work.

[I H8 UR DSM]

i was just busting your balls paul. : )

[Movingviolation240]

I know, but when have I ever not given out a smartass answer for somthing hehe.

Paul