Great write up Big V. You packed it with some great info.

 

I appoligize , but I need to make a huge correction on cam specs. Final correction on the 93 production cams.. They are all 240/248 the 248 exhaust cam is slightly different in it's placement from 91through early 93 models...

 

So your saying that the 93 isn't the crappiest after all? Hurray for me! I was feeling like an idiot for buying a 93. So does that mean they also have a decent stock ECU?

 

Now that answer all depends if you have SCV's are not.
The ecu tunes are different in comparison. First off on the later 93 production models the exhaust cam opens the Exhaust valve at 60* BDC, where as the 91 through some 93 production cams open at 64*BDC. This determines the difference in the tune because it changes the A/Fr's and apparently will change the power output. That still needs to be determined. Apparently as far as acceleration goes scv's help with lowend torque so if you have the 91 through early 93 productions with scv's the car will feel faster than a late 93 production without scv's.
Apparently 91through early 93 production years that have scv's are tuned for more fuel probably because there is additional swirl caused by the scv's for a more consistent mixture. So a late model 93 tune that doesn't deal with scv's and the change in the exhaust cam placement is probably much more mild.

On another note I have been researching why the change to a N60 or N62 MAF is much more important to use than a G60, or G70..
Here the crazy thing I don't get.... Gseries MAF's are smaller in diameter than the diameter of the TB!!!!!!!!!! This means that using a G MAF there is restricted flow through the intake system to the TB. The KA24de TB and KA24E both share a 65mm taper to a 60mm opening into the plenum port, (port size is 60mm).

PIC of G60 MAF interior diameter 59mm

KA24de TB 65mm taper diameter

Now just from looking at these pics you can see that flow is restricted as far back as the MAF. The MAF's proper diameter not to restrict flow to the TB should infact be 65mm or larger in order to make the intake system work as a velocity stack. This would help to collect more air right before it compresses in from the 65mm to 60mm TB taper, this allows the engine to use less energy and infact increase HP.
To step up to an N60 or N62 MAF an SAFC is needed or an ecu retune.
I chose SAFC only because I use it for testing, for people that know what there building ecu tune is the way to go.
Using the (N series) MAF on a 91-93 production ecu you want a in and out setting on the SAFC of 2in, and 6out, with a 1in, and 1out function. On 95-98 production it would be a setting of 2in, and 5out, with a 1in and 1out setting.

 

great post lot of good info...after reading all that i guess my only question is how do you determine which ka24de is under the hood of your 93?

 

Check for 2 solenoids behind the valve cover. If there are 2 solenoids behind the valve cover then you have SCV's. One solenoid is for the vacuum system.
Now to determine the head type OBD1 KA cylinder heads use 3 valve cover bolts next to the spark plugs. OBD2 use 2 valve cover bolts next to the spark plugs.

 

cooler of valve cover and bolts.. the older ( 91-early 95) Dohc were goldish tops

and the newer ( late 95 to 98) are faded silver

 

i have a question.


i have a '96 240sx .. and this weekend i will be acquiring a '92 DOHC KA (i plan to rebuild it)..

since the 92 is OBD1, and my car is OBD2, what all will i have to do to allow swapping of the OBD1 into my OBD2 car?

can i just swap the ECU, or is it more complicated than that?

 

Just switch over the block and internals, reuse everything else.

 

nah, i plan to overhaul this 92 KA completely, and swap it altogether... but when i'm done building it, and it's ready, i want to know what kinda work i'm lookin at.

 

ok vinnie i have a question about the e vs de tb. in the pic i see the tb tapper from 65mm to 60mm. correct me if i'm wrong but this velocity stack works as a tunning pipe would for the exhaust system right?

so with this in mind have you come across any info concerning the opposite approach taken on for the tb. that is 65mm to 65mm (bored out). so rather than compacting the air you in fact increase the volume of the plenum.

it seems to me that a combination of both would give better results. by using the velocity stack idea and adding a tb spacer you'd more likely that not see a significant improvement.

any thought's on this idea?

edit
it sounded good last night when i typed this but now it seems like i was going in circles.

a better way of phrasing it would be, do you believe that a 65mm bored out tb and 1" tb spacer would be over kill on na ka. i believe a velocity stack style or tapered tb and 1' spacer would work best. i've read some of your post on other forums concerning this but i can't find them. also i've noticed you've changed some of your views from about a year or two ago so some insight would be nice.

 

Well to be honest with you I have never seen anybody swap an older engine into their car. Vinnie or maybe Charles J could probably help you more than I.

 

bump for this question

 

Big Vinnie how to ident the camshafts. I mean how to know wich one is the exhaust and intake?
I just bought 2 camshafts supposedely from a 1991 KA so should be 240 and 248 as you said. The only marks I have on them are:
They both had a 53F marked and one has a big number 5 the other a big number 3.
Thank you for any help or confirmation if they really are a 240/248 cams.
Happy Halloween.

 

I never could tell by the numbers. I simply just look at a set of s13 cams which are 240/green on INT, 248/orange on EX, then I look at the dowel pin placement. (You will know this when you set up for stock cam timing configuration). Idf you have a set of the s14 ka24de cams it is 232/orange on INt, and 232/green on exhaust again compare the differences of the dowel pin location. You will know for sure if you have a set of s13 or s14 cams.