my comments on 248/240 s13 cam swap

Post by **Bigvinnie** » Fri Oct 27, 2006 3:21 pm

tloof wrote:Hey Dj,

Also you mention retarding the exhaust cam a bit as well which would delay the closing of the exhaust valve a few more degrees after TDC (this would increase the valve overlap slightly more which is what Nissan did on alot of the later KA engines in the Altima & Frontier to increase the midrange torque when they stated closing the exhaust valve at 7 degrees after TDC vs the 4 degrees after TDC that the 240SX's used...I'm not sure I understand comepletely why that really works, so I guess I need to analyze all of this some more).

I thought that the position of the exhaust cam placement was mostly determined for ignition timing and exhaust gas temprature.

Post by **InsanityInc** » Fri Oct 27, 2006 8:21 pm

I'm fairly sure the lower torque curve is for the 248/248. The other 2 are 2 runs at the 232/232 setup.

248/248 with a bit of a retard would probably do wonders for the low end, being that you'll get rid of some overlap which is undoubtedly causing problems there. Might even want to advance the exhaust a bit.

Post by **struckinc** » Tue Dec 05, 2006 9:43 am

DjPantsSpecR wrote:
i have a total of 3.3 dgrees of advance with my +5 set up. you would have 4 degrees of advance (by adding 2.5 degrees of advance). thats why i was recommending that for 248/248. definately dont retard it.

i should advance mine +5 right? since i am already at 1.5 atdc...advancing it 5deg would put me at 4 deg btdc? or am i confused again?

btw. i have already drilled a gear for 5 adv...would you recc. drilling more holes side by side for like 2.5 on the same gear?

Post by **DjPantsSpecR** » Tue Dec 05, 2006 11:17 am

yeah, i got really really confused to and i had some things backwards.

so, if you really are at 1.5 atdc, which is probably true for altima 248s (i dont necessarily believe what everyone says about s13 248s...) then a +5 degree advance would put you at 3.5 degrees btdc.

it seems like a bit much advance, especially when with 248's youre looking for top end power. i believe it works for s13 248's because our math on its position has been off and it is already too far retarded (it opens up a long ways after tdc) if you try and retard the 248 further i havent been able to make any decent powerbands. that alone leads me to believe that is is already too retarded, and needs some advancing.

thats where you come in: almost every dyno ive seen of 248 intakes has a dip in power around 4k. a little advance should helped get rid of this dip. there is all kinds of things ive discovered about these cams that i'd like to discuss, but im actually in class right now so i cant. but if you do this, you can let me know if you lose a bunch of top end and gain low end. so lemme know ASAP.

i would definately recommend drilling many holes like the JWT gears. it'll make your life more convienient later. hwat i do is drill one gear for advance (+2.5, +5, +7.5) and then do the same for a retard gear. And then i have two retard gears (cuz i wont be advancing both sides i can imagine....)

but another interesting thing to note about these gears is they are actually in increments of 2.1 degress. so 2.1 degrees, 4.2 degrees, 6.3, and 8.4 compared to 2.5, 5, 7.5, and 10. pretty big difference in actual advance i'd say.... so huge steps in advance or retard arent as huge as they might seem...

so for your case, i want you to help me with some research. on your 248, try everything. retarding should work to make top end power, while advancing should fill in the low end. try +5, +2.5, -2.5, -5. tellme what you like, then start messing with that 232. for that low duration and and early exhaust closing event i would try 2.5 degrees of retard , -5, and maybe -7.5

so for right now, and for a while now, i was *** backwards, and i dont believe that a 248 rotated 4 teeth really opens at 1.7 BTDC. so i ****ed up, and for altima 248's try retarding to make top end, advancing to make low end.

but thats why i need you to TRY it, and tell me if you find the same things

Post by **struckinc** » Tue Dec 05, 2006 4:20 pm

aight..no prob..i will try to drill the hole tomorrow and atleast try 1 advance saturday. i will let you know how that goes.

Post by **HKSdrift3r** » Fri Dec 08, 2006 9:15 pm

Hey DJpant.. I was reading your guide on the DYI cam gear and Im getting some confusion. Which template do I use to mark the hole, the inner or the outter? Also, it likes the advancements, for exapmple, 2.5* are just one tooth over. How would I go for aligning the cam back up? Thanks again!

-George

Post by **struckinc** » Sat Dec 09, 2006 8:12 am

you use the inner to mark the hole to drill and the whole template to make your new timing mark....and actually it looks like a 2.5 deg change is actually 2.2 deg. 1 tooth is 18.95 deg so it is about 1/10th of a tooth change

Post by **HKSdrift3r** » Sat Dec 09, 2006 8:45 am

kk thanks for trying to help me out but I still dont get it, so w/e I wont eve bother. Im planning on 240/232 on my s14 anyway so these adjustments arent entirely too necessary, Maybe some dif pics will help, like the actual lining up of the cam to the chain, but again, im no way of a rush. thanks guyz!!

-George

Post by **DjPantsSpecR** » Sat Dec 09, 2006 4:58 pm

nah, 240/232 sounds like could find some more top end with some gears.

okay, you mark and drill the inner holes. next to those holes they either have a letter or a number.

on the outer ring there will be a matching letter/number. this is the mark you line up on the chain when the cam's pin is in the hole you've drilled on the inner ring.

Post by **ArticDragon192** » Sat Dec 09, 2006 7:51 pm

Powerband of 248/248 in action in my S13 KA with stock timing on the cams

Power free ups include:RSR Exmag (3.1inches)Gutted CatDC Sports HeaderK&N Drop in with non resonated intake+5° in timing

Might start messing aorund with cam timing soon to massage more power out of the top end along with the S14 intake mani i have lying around.
Modified by ArticDragon192 at 8:01 PM 12/10/2006

Post by **DjPantsSpecR** » Sat Dec 09, 2006 8:02 pm

thats very cool man. its really 248/240?

it really looks like it wants to start making some top end power, so cam timing might be right up your alley.

good contribution to the 248/240 thread that has almost nothing to do with 248/240.

Post by **struckinc** » Sat Dec 09, 2006 11:42 pm

sorry didnt get too much done this weekend with the cams..it has been like 30deg down here this week...to cold to do much except find a heater..maybe next weekend if it warms up

Post by **struckinc** » Sat Dec 09, 2006 11:54 pm

HKSdrift3r wrote:kk thanks for trying to help me out but I still dont get it, so w/e I wont eve bother. Im planning on 240/232 on my s14 anyway so these adjustments arent entirely too necessary, Maybe some dif pics will help, like the actual lining up of the cam to the chain, but again, im no way of a rush. thanks guyz!!

-George

ok take the top template and cut it out so it looks like the bottom one under the gear of the first picture..this should fit inside of the gear exactly like the 2nd pic...then you mark what deg you want to adjust and drill accordingly...then you take the top template from the first gear..match up with the factory slot for the cam and match up the same number..for instance if you want to adjust for 5 deg you first mark INSIDE the gear for the 3 mark..then you use the WHOLE template lined up with the factory notch at 1...and mark the gear for number 3 of the OUTSIDE of the template this mark is your new timing mark for the marks on the chain

Post by **ArticDragon192** » Sun Dec 10, 2006 6:02 pm

DjPantsSpecR wrote:thats very cool man. its really 248/240?

it really looks like it wants to start making some top end power, so cam timing might be right up your alley.

good contribution to the 248/240 thread that has almost nothing to do with 248/240.

Oh whoops, typo there. It's actually 248/248 set up.

Post by **DjPantsSpecR** » Sun Dec 10, 2006 7:05 pm

yeah i thought so. 248/240 really does feel like poo even in comparo to 248/248 with stock timing.

its sad that i can spot that now though....

but sweet still man, good contribution, but now get out there and try some DIY adjustable cam gears

Post by **ArticDragon192** » Sun Dec 10, 2006 11:34 pm

I plan on doing so. gonna try out +5° on intake and see how that works. I just need a real intake on my car, haha. But so far all the other supporting mods have helped out a lot.

Post by **DjPantsSpecR** » Mon Dec 11, 2006 2:34 pm

for that i have to reccomend my true short ram intake:

search "30 dollar intake manifold" for a fairly decent pic of it....

that and i wanna see a dyno of that too....

Post by **ArticDragon192** » Mon Dec 11, 2006 10:49 pm

Was thinking more like AEM intake (because of carb and because cali sucks), along with a plenum over some GSX-R ITBs.

Post by **niemczykj** » Mon Dec 18, 2006 4:03 pm

i can get a Crower 264/264 duration 9.52/9.52mm lift cam for 300$....what do think? and do you have anyclue what my result would be?

Post by **DjPantsSpecR** » Tue Dec 19, 2006 5:46 am

no sorry, all that jazz is WAY over my budget.

my high compression build will be just under 200 dollars, and thats pushin it for me especially in this holiday season.

BUT: anyone can tell you this much. bigger lift, higher duration cams are always going to make, at the least, more top end power. i wonder what the actual duration on those 264's are, but there is no doubt that for 300 bucks its not that bad of a deal.

especially if you couple that with free diy cam gears. sorry i cant give you any specific info, but thats going to be a bit more difficult to find. you could be the first to let us know....

Post by **DjPantsSpecR** » Tue Dec 26, 2006 4:42 pm

today, i put 240/248 in to the car, and then i retarded the intake 7.5 degrees adn the exhaust 5 degrees ala the "tre setup" suggested by vinnie.

this is just my preliminary thoughts, but what the butt dyno shows is 248(+5)/248(-2.5) has a low end dip, but makes greater top end over 240(-7.5)/248(-5). i dont like where it starts to lose power after 6k, but everything before 6k is great, and drivability is also great. good luck not spinning tires into second gear...

its still clear something is happening with 248/248 do to this revelation. a seriously retarded set up like this shouldnt run and idle this well. i also dont think it should be mkaing as much torque as it is, however, its power curve is very very fat. it only pushes me to believe more that the 248 when used on the intake side is too retarded as it is, and requires advancement.

but this is just my first day impression and i havent got too many miles on it for the day. however, i will let you know vinnie after a while.

Post by **nissandrift** » Wed Jan 17, 2007 11:40 am

I've been thinking about trying the 248/232 and 248/240 cam setups, but Ive been trying to find dyno sheets to show the powerband. Im not looking at having anything to aggressive, but Id like something a bit more than the the 232/232 that I currently have in my motor. My motor currently has intake, pulley, 12lb flywheel, s14 exhaust mani, 3" sr DP, 3" exhaust, test pipe, no emmissions, or butterflys. Besides that I want to confirm that the cams I have are in fact S13 cams... is there a marking showing or part # on there? I have a motor that was in my old 93 hatch... but the front cover said 94, and there were not any intake butterflys. I knew the original owner, and she said the motor was never replaced but the car was a late 93. From what Ive been reading the 91-93 and 94 exhaust cams were a tad different. From what I read the 91-93 248 cam opens at 64 degrees BDC, and closes 4 degrees from TDC while the 94 248 exhaust cam opens at 60 degrees BDC, and closes 8 degrees from TDC.

Post by **spank044** » Sun Feb 25, 2007 7:05 pm

DJ, I have a 92 HB with a KA24DE. I have two sets of S13 cams and two sets of S14 cams and all the gears have been drilled out to the specs in your "DIY KA24DE adjustable cam gears." I was running the 248/232, but I have now rebuilt my engine with these specs.

-Stock pistons and crank, fully balanced and lighted crank and flywheel-Port and Polished head-4-2-1 Header-A similiar intake manifold to your "30 dollar Intake Manifold" but a little larger plenum-MSD 6A-370CC DSM injectors with custom High Flow fuel rail.-255 Walbro fuel pump

After reading through all of bigvinnie, tloof, insanity, and your posts and replys all over i have just gotten confused by the contradictory opinions.

I would really like an opinion on which setup(s) I should try first.

Thanks Steve

Post by **DjPantsSpecR** » Mon Feb 26, 2007 12:02 pm

i know, sorry spank this thread sucks. its more of a big learning experience than anything useful for tuning in one concentrated space.

but i like to see what you're doing, and i lik you have an intake manifold, although im not sure youre going to like haivng a larger plenum. but whos to say anything....

BUT: as of right now, this is the final word. First try stock cams at 240(-7.5)/248(-5).

i like this, its a fun little set up, okay midrange, okay top end. should compliment your intake manifold and high revs.

Now, i was, and still am a huge fan of 248(+5)/248(-2.5). there is something here that offers a big fat piece of torque and still seems to do okay in the top end.

however, i even forgot what set ups i was running, i've been stuck in intake manifold land for the past few months. And my car that ive been doing this swaps on doesnt run currently, so it hasnt moved in a long time. i wanted to do much kore cam swapping before i knew what i wanted.

But for now, i think you'll be happy with the two ive outlined. However:

if you cut your intake manifold in roughly the same spot i did, which is about nine inches from the back of the valve, you're gonna want to start with my 248/248 set up. This nine inch number comes from using the effective duration of the cam (241) in a certain eqatuons for runner length.

i was using that 248 set up when i was using my intake manifold, and its quite balls to the wall. I like the way the 240/248 set up feels on teh stock manifold, but it most likely wont react the same with shorter runners.

so how do you like that? more contradiction.... just start with 248/248 and then when you swap over to 240, you only have to change one cam. but i guess the same could be said either way....

now im just rambling.... but, this is my final word, with the intake manifold, use the 248/248 set up described. and then as a favor to me, experiment more with cam timing on it with the manifold. i've done so much to help people with this, and i havent recieved ANY feedback from people, even though i continuously ask.

Post by **spank044** » Mon Feb 26, 2007 2:06 pm

Thanks for the advice Dj, My plenum is only about 4 liters, I was looking at the intake manifold on my B18C1 a while back and started crunching numbers. It has a skunk2 manifold. So thats when I started looking at the short runner and large plenum idea and thought if it works for my Del Sol revving 9200rpm then maybe it will open up my KA. Then I started measuring and somehow I ended up with about eight inch runners and a little larger plenum then your design.

Also the snow is still coming down pretty good in MI so my car won't be out til its gone, but when I get it out and start testing then I will be sure to throw some butt dyno info up somewhere. Probably on a new thread since this ones gone to the dogs.

Thanks again.

One more thing do you know if neverlift ever got his manifold made up?

Post by **DjPantsSpecR** » Mon Feb 26, 2007 8:22 pm

no he didnt.

i built a 3.2 liter plenum, and it had horrible response, i really hated how it felt. i removed it immediately.

stock plenum is around 1.6 liters

Post by **neverlift** » Tue Feb 27, 2007 4:43 am

no unfortunately my time/money/work space is all limited atm, I do however still plan to make one just not so soon as I hoped : ( NICO will always get my results from things I do.

Post by **spank044** » Tue Feb 27, 2007 1:48 pm

Good to hear Neverlift. Dj, what size is the plenum in the pics of DIY $30 manifold?

Post by **DjPantsSpecR** » Tue Feb 27, 2007 4:19 pm

that one is roughly 1600cc's, which is about what stock is.

you ever read "how to build honda horsepower," by Richard Holdener? It sounds stupid, but they dyno parts back to back for the entire book. it shows you what makes power over what, and in what apps. Skunk2 ITR manifold on a B16 loses power everywhere except in the last thousand or so. However, you're reving to 9200 rpms where you would make huge gains over the del sol manifold, so you've clearly made the right choice. You measured around 8 inches on that manifold, well thats to make peak gains past 8k. its going to have to be a little longer on the KA depending on what intake cam you're using. I also hope you're measuring form the back of the valve.

you dont ever wanna build a plenum larger that the motors displacement in an N/A app. Now im speaking from experience here like i said before. My first plenum was 3.2 liters, to replicate the xcessive manifold, and i took it off immediately. i dont think you'll like a 4 liter plenum on N/A

Post by **spank044** » Wed Feb 28, 2007 1:26 pm

I am reading that right now in SCC Engine and Driveline Handbook. After I started talking to you I decided that I was going to get a new intake and cut my manifold volume in half and make my runners longer, but haven't deccided how long yet.

My first plenum was also going to be on a turbo engine so I was hoping to utilize the large volume in the higher rpm range anyways, but looking back on it now knowing the little more that I know now. It was a bad idea having it that huge.

my comments on 248/240 s13 cam swap

Re: 240/232 Combo for SC'd KA24de (tloof)

Re: (DjPantsSpecR)

Re: (HKSdrift3r)

Re: (DjPantsSpecR)

Re: KA24DE cam swaps (DjPantsSpecR)

Re: (nissandrift)

Re: (DjPantsSpecR)

Re: (neverlift)

Re: (DjPantsSpecR)

Nissan Forums

Infiniti Forums

Datsun Forums

Technical Forums

Classifieds / Marketplace

Nissan Motorsports

General Forums