KA Vs. SR
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Joined: Sep 2002
Posts: 680
From: Massachusetts
Out-revving isn't exactly out-performing. Line up a Civic SI spinning to 9k next to a 4th gen Camaro or Firebird and you can test that theory.
I would like the name of a shop that will give me my car back in three days with an SR. Generally, they want it for 2-3 weeks.
Like you said, the SR is a simpler proposition because everything has already been done on it, and the parts are available. If you know what you are doing
As far as running more boost, you don't need as much boost on the KA, and running higher compression means much better response before the turbo kicks in. This means that although the SR revs higher, a KA at a similar output level has a broader power band. That's not an indictment of the SR, it's just a property of the larger displacement.
-Justin
I would like the name of a shop that will give me my car back in three days with an SR. Generally, they want it for 2-3 weeks.
Like you said, the SR is a simpler proposition because everything has already been done on it, and the parts are available. If you know what you are doing
As far as running more boost, you don't need as much boost on the KA, and running higher compression means much better response before the turbo kicks in. This means that although the SR revs higher, a KA at a similar output level has a broader power band. That's not an indictment of the SR, it's just a property of the larger displacement.
-Justin
Originally posted by Justin.b
Both are great motors. If you go the SR route, there are plenty of parts and formulas that will allow you to get up in the hp range without any custom fabrication. If you go with the KA, you will have to find a lot of the parts by yourself and will likely have a quirky, custom one-off setup when through.
In the end, there really is no replacement for displacement, and the KA has a 20% advantage there. This means you can get the same hp numbers lower in the rev range on less boost. But since you're on your own, it may cost you more to get the hp out of the KA although it is larger.
-Justin
Both are great motors. If you go the SR route, there are plenty of parts and formulas that will allow you to get up in the hp range without any custom fabrication. If you go with the KA, you will have to find a lot of the parts by yourself and will likely have a quirky, custom one-off setup when through.
In the end, there really is no replacement for displacement, and the KA has a 20% advantage there. This means you can get the same hp numbers lower in the rev range on less boost. But since you're on your own, it may cost you more to get the hp out of the KA although it is larger.
-Justin
Originally posted by Justin.b
As far as ultimate limits go, I would bet you can do more with the the KA. The KA's bottom end is just as stout as the SR's and it doesn't have the weak valvetrain that limits the SR.
As far as ultimate limits go, I would bet you can do more with the the KA. The KA's bottom end is just as stout as the SR's and it doesn't have the weak valvetrain that limits the SR.
The SR valvetrain can be upgraded to help remedy the minor limit (in my view... a minor limit hehe
)But I would still go with the motor that is turboed from the factory cause its meant to run a turbo.
My cousin's shop can do it in aobut 3 - 5 days... I thought he was BSing me but he did do it in about 5 and half days (and that S14a is still running strong around south Sac) It takes pure dedication to that one car (as so my cousin says)
as so on my S14, we're aimming to do it in about a week
jus need some console parts and front clip from a shop near by, and I will be gone for a lil while
But ya... I'll post on when the swap will begin, and I'll keep u guys informed on how it goes
as so on my S14, we're aimming to do it in about a week
jus need some console parts and front clip from a shop near by, and I will be gone for a lil while
But ya... I'll post on when the swap will begin, and I'll keep u guys informed on how it goes
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Joined: Feb 2002
Posts: 1,841
From: NY
Why do you guys say that the KA has more potential? It's been argued over and over but when you get all the facts straight the SR has the Higher potential. Displacement is only a replacement for engines of the same design. Look at the RB26 and the 2jz. The 2jz has a good .4 liters advantage, but I've never seen one hit the same numbers as a RB26......
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Joined: Sep 2002
Posts: 680
From: Massachusetts
2jz's have been putting up huge numbers for a long time. There are several IS300's putting down more than 600hp at the wheels, and they're bulletproof at those output levels. I know there are many, many Supras cranking out well over 600 and several over 1000hp.
Other things equal, displacement is always an advantage. Both KA and SR are DOHC Inline 4's. They're definitely similar enough to notice the difference made by displacement.
It's certainly an easier path to follow with the SR since the motor has had the benefit of over ten years of attention from Japan's top tuners. The KA's that have been taken there so far have been done by individuals and their personal credit cards.
Personally, I don't plan on taking either of these engines anywhere near their limits. I will be assembling a turbo project based on a KA for cost and driveability reasons (stock bottom end, aiming for ~250 rwhp). I don't want to have to rev my car to 8k, 6k is fine by me.
-Justin
-Justin
Other things equal, displacement is always an advantage. Both KA and SR are DOHC Inline 4's. They're definitely similar enough to notice the difference made by displacement.
It's certainly an easier path to follow with the SR since the motor has had the benefit of over ten years of attention from Japan's top tuners. The KA's that have been taken there so far have been done by individuals and their personal credit cards.
Personally, I don't plan on taking either of these engines anywhere near their limits. I will be assembling a turbo project based on a KA for cost and driveability reasons (stock bottom end, aiming for ~250 rwhp). I don't want to have to rev my car to 8k, 6k is fine by me.
-Justin
-Justin
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Joined: Feb 2002
Posts: 1,841
From: NY
Displacement is not always an advantage. You're thinking in to much into such a general term. The SR's air flow set up is superioir to the KA's. Why? Well the KA wasn't meant to be a performance engine. Nissan isn't a bunch of dumb asses. If the KA has higher potential then why isn't it sitting in the Silvia stock? No one has or can build a KA to top the SR. You don't have any basis about the KA being better except for it's bigger......
BTW: the highest HP 2JZ was 1200+ right? Where as the highest HP RB is 1300+.
BTW: the highest HP 2JZ was 1200+ right? Where as the highest HP RB is 1300+.
Last edited by I'm with Stupid; Apr 15, 2003 at 10:37 PM.
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Joined: Sep 2002
Posts: 680
From: Massachusetts
Originally posted by I'm with Stupid
Displacement is not always an advantage. You're thinking in to much into such a general term. The SR's air flow set up is superioir to the KA's. Why? Well the KA wasn't meant to be a performance engine. Nissan isn't a bunch of dumb asses. If the KA has higher potential then why isn't it sitting in the Silvia stock? No one has or can build a KA to top the SR. You don't have any basis about the KA being better except for it's bigger......
BTW: the highest HP 2JZ was 1200+ right? Where as the highest HP RB is 1300+.
Displacement is not always an advantage. You're thinking in to much into such a general term. The SR's air flow set up is superioir to the KA's. Why? Well the KA wasn't meant to be a performance engine. Nissan isn't a bunch of dumb asses. If the KA has higher potential then why isn't it sitting in the Silvia stock? No one has or can build a KA to top the SR. You don't have any basis about the KA being better except for it's bigger......
BTW: the highest HP 2JZ was 1200+ right? Where as the highest HP RB is 1300+.
The Silvia received the SR20DET because of the legislation that penalizes motors over 2 liters. It's no coincidence that all these 2 liter motors displace just barely under 2 full liters from all Japanese maufacturers.
More displacement is ALWAYS better. In a turbo motor more diplacement means that you can make the same power lower in the rev range with better off-boost performance at lower boost levels. I fail to see how this could possibly be a disadvantage if you want to build an engine that makes as much usable power as possible.
If the KA had seen the constant attention of Greddy, Top Secret, JUN, etc for 10+ years we'd all be saying SRwhat? That isn't the case. In order to benefit from the trial and error of people with much larger budgets than ours we go with the SR.
Duy's KA+T has to be putting down 450+hp at the wheels in order to run 10's in an S14. That's got to be over 520hp at the crank. That doesn't match the most powerful SR's, but this was built by one guy in his garage.
Assuming the purpose of the motor is to make as much usable power as possible, there is no way I will ever condede that it is better power-wise to build a motor with less diplacement. If there are other considerations (weight, emissions, tax / insurance penalties) then you have to make compromises. But if the end goal is to outright make the most power possible, the larger motor is always the better choice.
-Justin
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Joined: Jul 2002
Posts: 709
Originally posted by Justin.b
But if the end goal is to outright make the most power possible, the larger motor is always the better choice.
-Justin
But if the end goal is to outright make the most power possible, the larger motor is always the better choice.
-Justin
i agree with you that there is no replacement for displacement, but weight plays a big role. generally, larger displacement engines weigh a lot more then smaller displacement. the real way to measure a car's ability is its power/weight ratio. indy cars are like 1.5 liters or something but they're making insane hp. however, this point is doesn't play a big role in the SR vs. KA question, although the SR is 50lbs lighter with the turbo then the KA without a turbo.
this is the way i look at it-
at 7psi the SR20DET makes 205hp
at 7psi the KA24DET makes ~240hp (based on nsport)
the SR20DE makes somewhere around 120hp (can't remember exactly and too lazy to go look)
the KA24DET makes 155hp
let the numbers speak for themselves
i've heard arguments that the SR has a better head design and what-not, but based on the numbers, it doesn't seem to be playing a very large role at all. also, internals do not break b/c of boost, they break b/c of detonation. if you have an adequate fuel supply and the right octane, you're not going to break your internals unless you are running absolutly insane horsepower.
also, about the comment that the KA doesn't rev as high as the SR. the s13 KA revs to 6900, rev limiter at ~7300. the SR redlines at what? like 7000 or 7200 right? not that the KA needs to rev that high to make its power (which is an advantage), but it can.
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Joined: Feb 2002
Posts: 1,841
From: NY
Originally posted by spitz7985
this is the way i look at it-
at 7psi the SR20DET makes 205hp
at 7psi the KA24DET makes ~240hp (based on nsport)
the SR20DE makes somewhere around 120hp (can't remember exactly and too lazy to go look)
the KA24DET makes 155hp
let the numbers speak for themselves
this is the way i look at it-
at 7psi the SR20DET makes 205hp
at 7psi the KA24DET makes ~240hp (based on nsport)
the SR20DE makes somewhere around 120hp (can't remember exactly and too lazy to go look)
the KA24DET makes 155hp
let the numbers speak for themselves
And to what Justin said.... You are giving displacement way too much freaking credit. .4 liters in a inline 4 with a restrictive head design, extremely long stroke, and a very small rod ratio doesn't do ****. When Duy's car was putting down 450+ hp it was FULLY upgraded. There wasn't anything more he could do to that engine with out blowin it. A fully upgraded SR can go to 600 HP.
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Joined: Sep 2002
Posts: 680
From: Massachusetts
Originally posted by I'm with Stupid
And to what Justin said.... You are giving displacement way too much freaking credit. .4 liters in a inline 4 with a restrictive head design, extremely long stroke, and a very small rod ratio doesn't do ****. When Duy's car was putting down 450+ hp it was FULLY upgraded. There wasn't anything more he could do to that engine with out blowin it. A fully upgraded SR can go to 600 HP.
And to what Justin said.... You are giving displacement way too much freaking credit. .4 liters in a inline 4 with a restrictive head design, extremely long stroke, and a very small rod ratio doesn't do ****. When Duy's car was putting down 450+ hp it was FULLY upgraded. There wasn't anything more he could do to that engine with out blowin it. A fully upgraded SR can go to 600 HP.
There are no inherent advantages to the design of the SR over the KA. The SR has benefitted from millions of dollars in R&D over a decade. The KA has seen sporadic attention from a small group of not so well funded individuals who don't necessarilly share the information they discovered with others who may run across the same problems.
End result is that a nation of tuners got the SR to 600hp over a period of ten years. A few privateers in the US have seen slightly less spectaular numbers, but ran lower boost to do so and likely had more area under the curve. Not much of an issue any more anyway. Both motors are scrapped so we're not likely to see much / any R&D going to either of them.
-Justin
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Joined: Feb 2002
Posts: 1,841
From: NY
If the 20% advantage of displacement is as big of an advantage as you say then why aren't turbo KA's out kickin *** on SR's? It's not like you have some secret information that nobody wants to admit that the KA has more HP potential because it doesn't. That's why the tuning market doesn't have parts for it. There wereseveral companies in Japan that fixed up KA's but for the reasons I keep saying it didn't go very far. If you really want to read up on the differences of the engines go over the freshalloy and look at the old KA vs. SR dicussions and you'll see what I'm saying.
Edit: BTW that extra displacement isn't an advantage because it all comes for the engines very long stroke. And as you know a long stroke is horrible for a performance engine. I don't think there would be a better example of this than if you were to compare Toyota's 4A-FE and 7A-FE. In stock form the the 7A has a 10 hp advantage over the 4A, but if you want a high hp engine the 7A get's it *** kicked by the 4A.....
Edit: BTW that extra displacement isn't an advantage because it all comes for the engines very long stroke. And as you know a long stroke is horrible for a performance engine. I don't think there would be a better example of this than if you were to compare Toyota's 4A-FE and 7A-FE. In stock form the the 7A has a 10 hp advantage over the 4A, but if you want a high hp engine the 7A get's it *** kicked by the 4A.....
Last edited by I'm with Stupid; Apr 16, 2003 at 09:52 PM.
Duy is the guy I was talking about... blew like 3 or 4 KAs to do wut he has achieved....
most likly, the KAT is for thos who want to stand out from the norm
but if u really look at it... the SR is the higher potential because its smaller, yet power output exceeds the KA by far. I have yet to see or hear about a KAT that pushes higher and harder than Duy's (I believe he sold his Silvia tho), and thats 450 WRHP.
SR I have seen/heard/spec them achieving numbers way beyond Duy's. (I know I need to explain more about my point... but again its that time of the night)
and as for the 2JZE, theres a guy in Texas who pushes 800 WRHP on a stock bottom end... STOCK BOTTOM END! (gotta luv em Supras and them Texans for bein that crazy) now imagine if them guys started wrkin on the rest of that 2JZE... 2JZEs are limitless in that category (and so as the RB25 and RB26)
but back to the topic, As to wut many have told me... the SR is the motor to go in this category, a very high potential motor...
another point = the KA has a high compression, u cannot run a very high PSI unless u start wrkin on internals.
one last thing, for $ wise, SR swap would be cheaper over KAT... the price of the turbo kit for the KA is about 2K.... then u pay for installation (if ur not sure about installing it urself) and then other parts for the turbo set-up... that only lets u have a basic turbo set-up under the hood. Dun forget how much $ it will cost to wrk on the KA to reenforce the block to handle more pressure, very expensive...
best thing to do... swap in SR and save up for front IC and cone filter... maybe T3/T4 hybrid turbine and ur done for the moment...
KA, ur looking at building a full turbo system on an NA block.
or... go psycho.... RB25DET with the 3rd stage valve train (stock on the Neo R34) and blow away any Mustang around well, u can beat mustangs with a stock KA (yes tried it before I luv seein their reactions 
)
oh and to whomever said put a civic that revs up to 9000 PRM vs a Firebird... check out the vid here... this is so embarrassing to know about Firebirds...
http://www.geniusinside.net/fuelslut/GopedTake2.wmv
Kinda shows u that size really doesnt matter
most likly, the KAT is for thos who want to stand out from the norm
but if u really look at it... the SR is the higher potential because its smaller, yet power output exceeds the KA by far. I have yet to see or hear about a KAT that pushes higher and harder than Duy's (I believe he sold his Silvia tho), and thats 450 WRHP.
SR I have seen/heard/spec them achieving numbers way beyond Duy's. (I know I need to explain more about my point... but again its that time of the night)
and as for the 2JZE, theres a guy in Texas who pushes 800 WRHP on a stock bottom end... STOCK BOTTOM END! (gotta luv em Supras and them Texans for bein that crazy) now imagine if them guys started wrkin on the rest of that 2JZE... 2JZEs are limitless in that category (and so as the RB25 and RB26)
but back to the topic, As to wut many have told me... the SR is the motor to go in this category, a very high potential motor...
another point = the KA has a high compression, u cannot run a very high PSI unless u start wrkin on internals.
one last thing, for $ wise, SR swap would be cheaper over KAT... the price of the turbo kit for the KA is about 2K.... then u pay for installation (if ur not sure about installing it urself) and then other parts for the turbo set-up... that only lets u have a basic turbo set-up under the hood. Dun forget how much $ it will cost to wrk on the KA to reenforce the block to handle more pressure, very expensive...
best thing to do... swap in SR and save up for front IC and cone filter... maybe T3/T4 hybrid turbine and ur done for the moment...
KA, ur looking at building a full turbo system on an NA block.
or... go psycho.... RB25DET with the 3rd stage valve train (stock on the Neo R34) and blow away any Mustang around
well, u can beat mustangs with a stock KA (yes tried it before I luv seein their reactions )oh and to whomever said put a civic that revs up to 9000 PRM vs a Firebird... check out the vid here... this is so embarrassing to know about Firebirds...
http://www.geniusinside.net/fuelslut/GopedTake2.wmv
Kinda shows u that size really doesnt matter
Thread Starter
Registered User
Joined: Apr 2003
Posts: 115
From: Miami, Florida
Well, I'm glad to have gotten so many opinions on the subject. I was planing on going with the SR anyway, but I was interested in knowing if the KA had potential. Anyway, being that I want to do the SR20DET swap, how much should i be expecting to pay for a motor, with appx. 20-30k miles. And also, how much more should I expect to pay if I want to add a 6 speed tranny to it?? Thanks for all of your help.
