This thread was saved without dates. "Around Sep 2004" is estimated from neighbouring threads.
1-ca20 bottom end
2-ca18de head
3-boost from aftermarket det mani
4-t-25turbo mated to the t2 housing
5 -intercooled of course
I plan on using the wiring harness and ecu from a 88 pulsar as that is where I am getting the head from. As for the injectors where can I source the top feed rail from? Speaking of injectors what size do the ca18et motors come with stock? any thoughts on this theroicatical motor build?
read the archives but not the current posts--now I feelin kinda dumb
well dont boos the ca20e bottom to much 4-6psi or you will pop a rod.. youd be better off just using the ca18et bottom and doing a slight port/polish euro cam, 240sx tb, bigger exhaust and then you can have some fun
CA20 rods = Crap
You wouldn't be able to use the CA18DE wiring harness or ECU though if you plan on running boost either. Same idea as bolting on a 1G Turbo manifold and 14B onto a 1G Talon N/T and expect it to just work. Not going to happen. The correct way would be to buy a CA18DET wiring harness and ECU from a Jap Spec importer and use that. Then you would be set.
or just use the stock ca18et wiring harness and just add a s-afc
I think you already read my other post, but if you're building the CA20, I've got some ideas... :mrgreen:
Yeah, if you're going with the de head, you'll have to either get a DET wiring harness, or run stand alone since the de head doesn't have a place for a distributor. Or, the CA18DET JDM motors are still pretty cheap to pick up...
Now, here's an oddity ... I was looking at a ca16de powered Pulsar ... and it does have a distributor, in the same location as ours.
hmmm... Well I know the ca16de has smaller intake and exhaust valves, already looked into that on my software, but if it's a bolt on, it still might be an advantage over the sohc head. Or, if there's a space for the dist. on the CA18DE head, and you use CA16DE cams, then that would work too... Man I need one sitting here so I can look at it...
That would be awesome if we could use that!
I was junkin the other day and found a 200 w/ the ca20 and next to it was the pulsar with the de head w/ dist. now I am thinking that with slight machine work on a set of DSM rods we may have an interesting bild prospect. Oh did I mention that I am getting all this for next to nothing? I have a car ready to junk here and am trading it off to the yard for parts.
huh? I had a CA16DE pulsar and it had the CAS unit.
, it still might be an advantage over the sohc head. Or, if there's a space for the dist. on the CA18DE head, and you use CA16DE cams, then that would work too... Man I need one sitting here so I can look at it...
That would be awesome if we could use that!
man why does everyone diss the sohc so badly...is noone but me really willing to take it to the max before you swap on a dohc head which you will lose bottom end with and unless you get your internals balanced and rev limiter disabled(if you have one) you wont see any advantage of the dohc since it makes almost all its power in the top end.... i know this sounds harsh but i also know that if jason(arro) read this he would be way more harsh then i am being..
i'll make you guys a promise right now i will take the sohc into 300+hp and run no slower then the 12's....and make it there with alot less work and money then getting a dohc swapped on our blocks..
I have to agree with you Bart. I don't see the need for a dual overhead cam setup on these engines. Some good port and polish work and improved fueling and a better turbo will get some very impressive gains.
A person with an IQ of 60 can see the DE head flows a lot better than the SOHC head that's why everyone wants the DE head. But I do agree Noone has really done anything big with the SOHC head besides a decent street cam and some porting and polishing.
A person with an IQ of 60 can see the DE head flows a lot better than the SOHC head that's why everyone wants the DE head. But I do agree Noone has really done anything big with the SOHC head besides a decent street cam and some porting and polishing.
well not for too much longer
I'm not trying to say anything bad about the SOHC head, I know it has potential, but seriously, which one do you think will flow better? A fully ported and polished SOHC head or a fully ported and polished DE head? I know I'm not gonna be pushing the upper realms of horsepower on this build, but I might want to later on, so why not just get it set up now so I won't have to upgrade later?
Seriously, just because everyone doesn't want to do the same thing doesn't mean you have to go ape-nuts...
I want to do it most of all just for the plain joy of hot rodding something that hasn't really been done before. I like my little frankenstein motor, and as long as I can figure more hybrid junkyard junk to put on it I will!!! 8-)
I was pretty fricking surprised.
We were looking for ca18de powered pulsars, and actually found one, just couldn't be bothered to tear into it.
I popped the hood on another one, saw the boring valve cover, checked the engine tag, and saw ca16de. I was about to jump down and close the hood (they stack them) when I saw the distributor.
But thinking back, I remember seeing other ca16des with dizzys
If you compare the intake and exhaust ports on the SOHC head to those on the DOHC head you will find that the DOHC head ports are twice as big. This mean twice as much flow, and twice as much power. Also, it's more advantages in terms of gearing to make the power at a higher RPM. It would not be possible to port the SOHC to flow as much as the DOHC based on port size and valve size alone. Not that a SOHC head can't make power, but it would be a lot easier to make the same power on the DOHC head. As soon as I get some money for rods and what not, I'll try swapping on my DOHC head with the stock ecu just to prove it can be done (realitively) easily. It will probably be about this time next year before that's done though.
Also, you generally won't lose that much bottom end, especially with the stock cam. The standard manifold shuts down one set of intake runners to help increase velocity. A similiar system was used on the 4AG-E engine to help out bottom end. The DOHC redlines at 7500rpm, so with the stock cams, it should work great from the 3500-7000 rpm range.
If you compare the intake and exhaust ports on the SOHC head to those on the DOHC head you will find that the DOHC head ports are twice as big. This mean twice as much flow, and twice as much power. Also, it's more advantages in terms of gearing to make the power at a higher RPM. It would not be possible to port the SOHC to flow as much as the DOHC based on port size and valve size alone. Not that a SOHC head can't make power, but it would be a lot easier to make the same power on the DOHC head. As soon as I get some money for rods and what not, I'll try swapping on my DOHC head with the stock ecu just to prove it can be done (realitively) easily. It will probably be about this time next year before that's done though.
Also, you generally won't lose that much bottom end, especially with the stock cam. The standard manifold shuts down one set of intake runners to help increase velocity. A similiar system was used on the 4AG-E engine to help out bottom end. The DOHC redlines at 7500rpm, so with the stock cams, it should work great from the 3500-7000 rpm range.
those of you lucky in not haing the rev limiter will see good benifits...but me i love bottom end torque and theres no way a dohc setup on cars will have close to the tq and as low as the sohc, unless you are making a bit of power 400hp+
Here is a link to a dyno post of what looks to be a CA18DET with relatively little mods (except the guy is on a stand alone computer).
http://www.nissaninfiniticlub.com/zerothread?id=76355
He is near max torque by 3800 rpms. Your dyno slip shows your getting max torque around 3200 rpms. 600 RPMs different from when you guys come on cam/boost. I'll make a chart..
RPMs..........SOHC..........DOHC
2500............125.............115
2750............150.............130
3000............165.............150
3250............185.............160
3500............185.............175
3750............190.............180
4000............190.............195
Too much past this point and your car starts running out of boost. The DOHC car is on a t-25, so it also will not spool up quite as fast as the T2 (although it won't be far behind). Let's say you were to drag race this guy, you would make more power below 4K rpms, however you are only below 4K rpms on the launch (and if you slip the clutch, you won't be there then either). You will be above 4K rpms for the rest of the race, thereby negating any bottom end benefit. Also, you will have to shift at 6500 rpms or so just because the head won't flow enough to make power up there, while the DOHC guy could go to 9k or so. This is assuming both engine have had the heads ported and can actually spin that high without coming apart. So pretty much throughout the race, the other guy would be one gear lower than you and able to accellerate harder because of that.
Bottom end torque is great and all, but we have 1.8L engines, so it won't matter what head we have on it, it will not have any. The only spot where the SOHC really beat the DOHC head by more than 15 lb/ft is where the T2 spooled and the t25 hadn't yet. The best way to make up for the lack of a bottom end is a very high numerical final drive. With our 4.11 gears, we don't have to worry about bottom end once we cross 15 mph.
Another interesting calculation, with a 6K rpm redline gears roughly top out at: 30, 50, 78, 100, 130. With a 7500 rpm redline, this changes to, 37.5, 62.5, 97.5, 125, 162.5. With the SOHC head, you will be almost done with fourth by the time the DOHC cam guy runs out of third. At a 1/4 mile track, I have to go to fifth gear to finish. If I was DOHC, I would have just shifted to fouth. That's a lot of gearing to be missing out on.
As for not having the rev limiter, I know my car certainly doesn't have one so it wouldn't be a problem to use my stock ecu (who knows how many others are blessed/cursed with this). Most other people that are wanting to do the DOHC swap however, are planning on using the DOHC ecu to go with it, so the rev limiter won't be an issue.
It's hard to not see the many advantages of going DOHC. The only real downside is the amount of work it would be to do. The other thing is, can you still really call it a 200SX engine at that point?
Very well said... 8-)
Now, just a question since you said you're planning on doing the swap. Are you gonna use a stock Pulsar ecu? You think that'll work alright since it was designed for use in a NA motor? If the wiring harness and sensors are the same, we could just nab a CA18DET ecu, but I'm not sure if there's all that much of a difference between the two.
I found a Pulsar with a CA16DE for $200, but the more I thought about it, I can't really use the CA16 head, so all I'd be getting out of it was the wiring harness basically...
As far as calling it a 200SX motor, heck yeah it's still a 200SX motor! This is pure hot rodding right here, using junkyard parts to make our cars better...
I was going to use the CA18et ecu.
I was pretty fricking surprised.
We were looking for ca18de powered pulsars, and actually found one, just couldn't be bothered to tear into it.
I popped the hood on another one, saw the boring valve cover, checked the engine tag, and saw ca16de. I was about to jump down and close the hood (they stack them) when I saw the distributor.
But thinking back, I remember seeing other ca16des with dizzys
Uhhh, Did you say you saw a dohc motor with a dizzy? Is it also a 8 plugger? A person could then build a ca20de/Ca18det using that head and the stock electroncs just by swapping the dizzies or using using the one that is already in the head. The De intake and exhaust manifolds are different though arn't they?
The standard manifold shuts down one set of intake runners to help increase velocity. A similiar system was used on the 4AG-E engine to help out bottom end.
You won't want those.... It'd be an awful shame if one of those butterfiles blew off and it's pieces got sucked into the engine. they aren't made for boost.
You won't want those.... It'd be an awful shame if one of those butterfiles blew off and it's pieces got sucked into the engine. they aren't made for boost.
actually they will be fine the ca18det's have them as well actually that part is sepeate from the mani and is the exact same unit that is used on the ca18de.. so no wqorries about it breaking under boost
I guess they're sturdier than the toyota's then. There was an HKS turbo kit for the 4A's and it told you to unplug the vacuum line for the TVIS (this kept the runners open). The 4AGZE's don't have the TVIS
Hey, speaking of TVIS, I'm rebuilding a 4AGE right now that sucked a TVIS screw down the intake. Let me tell you, a screw imbedded in the top of the piston is not a good deal... :mrgreen:
Car had a knock in it, he thought it spun a bearing, I went and checked it out and the bearings were fine. So, he pulled the motor, and when he brought it to me, he said, "one of the screws out of the TVIS is missing, where could it go?" :mrgreen: There's only one place for it to go buddy...
So, I've been a little bit scared of em since then, but it could have just been a freak accident...
Yeah ... the secondary butterflies are a good "stock" set up piece ... but in actuality, it's been proven that the motors with them (ca18det and ka24e/de) actually make more power across the band by removing the butterflies altogether.
Hands down I will always pick a car with big low end over a high winder for drag.
Way too nerve racking to have to hope you get the holeshot.
Anyone know how the FWD USDM ca18de's intake manifold compares to the ca18det? That's where 9/10s of the R&D went.
The final word is, how often are you actually going to take it to 7000 rpm on the streets on your daily drive to work? Not very often. In the same drive to work, how often will your car see 2000 - 4000 rpms? Constantly. Every single stop light, stop sign, or highway merge is going to require power in this area. The SOHC is great at this because it always provides the most power right where you need it. DOHC may be better for racing, but on a daily driven car, you can't beat the original SOHC head.
Yeah, but I think the point one_equals_two was making was that the DOHC doesn't really give anything up down low, but continues making power up high after the SOHC levels off... :dontknow:
Yeah, but I think the point one_equals_two was making was that the DOHC doesn't really give anything up down low, but continues making power up high after the SOHC levels off...
DINGDINGDINGDING!!!!!
We have a winner!!!!!!!! I've driven a CA16DE pulsar and they were pretty quick for what they were you didn't have wind it up as much as a 4A either. You guys make it sound like turbo lag as far bottom end. I don't know where this comes from. Most of the 4AGE guys just exaggerate and say they have no bottom end to speak of. I driven a 4A too they don't have a lot of bottom end but it's not horrible.
i don't know where everyone get's that DOHC engines have nothing on the bottom if they didn't have a bottom end you'd have to launch them to move them. Even if that was an issue in a race do you actually use bottom end? Do you launch at an Idle? Noooo... So in a race is the car almost entirely in top end of it's powerband. :banger:
Oh so CA18DET's are great on the track but horrible to work....even in stock form? even it's very possible that their designed in a country where stop and go driving is the rule. Yah surely becuase you have to launch it at every stop light. If a CA16(8)DE is decent to drive in the city then a CA18DET should be fine as well.
And beside the point that if you want awesome driveability you should leave the car stock. Don't change it, don't modify it. You'll have perfect driveability. Just like it was from the factory.
Sorry for the slight rant I just don't know why some are against the DOHC stuff. Being able to integrate that head with the stock electronics would be a break through and I'm sure jason wouldn't mind the drive to work even if he doesn't wind it out.
edit oh one thing noone's thought of yet with 14 psi and that DOHC head you'll probably reach the limits of the fuel system. Quite quickly I might add
The fuel limit would be reached pretty quickly. And the MAF sensor limit would easily be reached. At 14 psi and 6K rpms on the stock head my S-AFC shows that I am using about 95%-98% percent of the MAF sensor capacity. A MAF sensor upgrade would be a requirement.
ka maf would get you another 10 or so % and a z31 would give you about 40% more flow