my comments on 248/240 s13 cam swap

Information on the naturally-aspirated KA24E and KA24DE engines.
User avatar
480sx
Posts: 4085
Joined: Sun Nov 12, 2006 5:27 pm
Car: 1996 Pearl White 240sx

Post

Bigvinnie wrote:

Your timing advance is dependent on what plug type you use.

More advance is higher for the plugs. More retard is lower on the plugs.


In that way it is dumb. The arbitrary numbers that you have listed for advancement after said spark plug also is pretty dumb.

That link or quote does not back up much if any of the stuff in your post. I THINK what your trying to say is that a platinum tipped plug or a iridium tipped plug will withstand the hotter temps associated with a more advanced engine.. While this might be true(to an extent), it has very little to do with advancing timing on an engine. EGT's and knock levels tell you how far you can advance an engine, NOT your freaken spark plugs. If your running NGK coppers on a highly tuned high EGT running engine, its a given your going to be replacing your plugs often.

Excessive EGTs are going to damage any spark plugs in the same way a copper plug would be dammaged. A plug is more than just the center electrode. Heat is going to destroy the ground electrode exactly the same with whatever plugs you use. Both parts of the plug are equally important.

You dont tune an engine around the type of electrode you choose to use for your plugs. PERIOD.
Modified by 480sx at 9:58 PM 7/27/2008


User avatar
redtop91
Posts: 16326
Joined: Thu Sep 07, 2006 9:05 am
Car: ↑ ↑ ↓ ↓ ← → ← → B A Start

Post

Bigvinnie wrote:
Your timing advance is dependent on what plug type you use.

If you are using copper plugs at most you will be able to get a 6 degree advance before having to adjust the A/Fr's.

With platinum plugs almost a 9~10 degree advancement from these plugs before adjusting the A/Fr's.

Iridium plugs are pretty much limitless to how far you want to advance.

It's teh heat range that the plugs handle. More advance is higher for the plugs. More retard is lower on the plugs. Iridium plugs are usually meant for high compression and lots of advancement.

Now this is how relevant and cold burning the plugs are, and how much flame front prorogation increases from timing advance.

The reason why I like the SAFC2 for basic naturally aspirated engines is because it gives alot more tuning for such a short amount of time (time paid for dyno use). On the dyno when you see the A/Fr's become to lean or see that the egt is getting higher. You can very quickly tune around a situation like that using the SAFCespecially when you tinker with base timing..I think you will see it can become beneficial.

Modified by Bigvinnie at 5:04 PM 7/27/2008

Bigvinnie
Posts: 1079
Joined: Thu Apr 07, 2005 2:07 am
Car: 2004 Nissan Frontier desert Runner, 2014 Nissan Titan

Post

480sx wrote:

You dont tune an engine around the type of electrode you choose to use for your plugs. PERIOD.
You can tune around the thermal properties of a spark plug. It's condition has more to do with the center electrode used. Which in most cases the melting point of copper is much lower than platinum, as to platinum is much lower than iridium.It's the melting point of the spark plug that will cause 90% of misfire that starts the KNOCK and PING process. A spark plug can work as a hot spot just as many parts of the compression chamber can.Personally I've done tests between copper, platinum and iridium plugs on my KA24de. The bosch platinums were the worst by far. If you research the bosch platinums there just platinum tipped with a copper center electrode. They don't take to well to heat at all. The severity of the heat caused over a long period of time causes these plugs to misfire very early in its life cycle. I was only able to use the bosch plugs for about 10,000miles before they were changed out and I had timing advanced to 26BTDC. There weren't any serious HP improvements either.Then I tried the NGK copper plugs which run about $2.00 at most local stores. I was actually able to make timing advancement the same as the bosch platinums. They also lasted longer Then the platinums by about 13,000 miles total. The thermal properties of the NGK copper plugs are much better suited than the Bosch platinums.So after having my KA24de for 4 years I decided to step up to NGK iridiums. Which even claimed higher heat tolerances and a lower cooler plug than any other plug on the market. I payed $12.00 a plug. I ran the timing advance at 6 degrees (26BTDC) and about 10,000miles with no problems. I have ran the plugs up to 28Degrees BTDC before power starts to drop due to lack of fuel and octane that is required. Overall they do with stand the test of time and take a serious amount of heat tolerance when compared to the coppers or most platinums on the market. I wouldn't be surprised if a little added fuel would increase power as far as 10 degrees BTDC.Now I do apologize for mentioning raised egt in advanced timing which simply isn't the case. The temperature does raise within the igniton process when timing is advanced , but it allows the burn off to start sooner which actually allows the egt to be less, than it would be as if timing was retarded.As far as I know I continue to use the iridium plugs and still to date have no problems.... Still to date I have an all stock block KA24de with 240/248 cams maxed at 162 WHP. No one still to date has matched my HP rating in any forum.So make what ever you want believable, plugs do matter.

User avatar
480sx
Posts: 4085
Joined: Sun Nov 12, 2006 5:27 pm
Car: 1996 Pearl White 240sx

Post

1084.62 C is the melting point of copper. If your EGTs are that high your fvking electrode melting is the least of your problems.

Bigvinnie
Posts: 1079
Joined: Thu Apr 07, 2005 2:07 am
Car: 2004 Nissan Frontier desert Runner, 2014 Nissan Titan

Post

480sx wrote:1084.62 C is the melting point of copper. If your EGTs are that high your fvking electrode melting is the least of your problems.
O.K now try to make copper a electrical conductor at a fraction of that temperature. Greater heat only adds more resistance.... Copper is worthless.

User avatar
alkemyst
Posts: 310
Joined: Tue Oct 28, 2003 5:46 am
Contact:

Post

how much power was 10 degrees worth over 6 degrees in your car?

If the higher advance did make me more power, I was planning on moving up from copper plugs.

Bigvinnie
Posts: 1079
Joined: Thu Apr 07, 2005 2:07 am
Car: 2004 Nissan Frontier desert Runner, 2014 Nissan Titan

Post

alkemyst wrote:how much power was 10 degrees worth over 6 degrees in your car?

If the higher advance did make me more power, I was planning on moving up from copper plugs.
There is no need to advance timing to 10 degrees unless your doing some sort of special cam set up, and adjusting your A/Fr's. After 8 degrees BTDC of Timing engine power actually falls off and starts to drop. Regardless of the plug type used and I think that has more to do with the fact that the burn starts to early.

As you run timing to about 6 and 7degrees BTDC timing, it starts to shorten plug life literally by half. (Atleast I know it does that with copper plugs.)

If you do decide to advance timing between 7 and 8 degrees timing I would personally go for NGK laser platinums, or NGK iridiums.

Even NGK recommends that you don't go past 10degrees of advanced timing since temperature increase to the plugs is on average 70~100* C higher.

This is the timing advance chart that I normally follow by Champion Spark plugs..<br/>Shot with <a target="_new" href="http://profile.imageshack.us/camerabuy. ... ">E2100</a> at 2005-07-08

User avatar
alkemyst
Posts: 310
Joined: Tue Oct 28, 2003 5:46 am
Contact:

Post

i am looking for someone that tested this...not just posting up honda stuff. If my plugs die at 15k vs 30k that`s fine.

I will be playing with this anyway next week or so on a dyno.

sticky_steve
Posts: 163
Joined: Sun Dec 24, 2006 12:27 pm
Car: 1991 300zx
2003 350z

Post

OK so I'm gonna bring an old thread back to life. I have a 93 block w 95 head and i just installed the 248/232 swap, and it feels great. But i was reading that i need to advance 2.5 degrees, but then the #1 lobes won't face directly to the outside. Is this correct and all i have to to is just loosen the bolt and advance it? Oh and by the way i did rotate ccw 4 teeth. Or am i mising something

User avatar
alkemyst
Posts: 310
Joined: Tue Oct 28, 2003 5:46 am
Contact:

Post

sticky_steve wrote:OK so I'm gonna bring an old thread back to life. I have a 93 block w 95 head and i just installed the 248/232 swap, and it feels great. But i was reading that i need to advance 2.5 degrees, but then the #1 lobes won't face directly to the outside. Is this correct and all i have to to is just loosen the bolt and advance it? Oh and by the way i did rotate ccw 4 teeth. Or am i mising something
You aren't going to be able to advance it 2.5 degrees without a special gear. As far as what the alignment looks like, it's hard to tell it's even moved.

I am running mine 2.5 degrees retarded. It loses a bit of power across 0-4500/5k, but it stays on power to redline. Advanced, the power would fall right around 5k. Running the cam without a gear may be a good compromise, but I have not tested that on a dyno.

I also advanced my timing a bit. You really need to be using only premium gas (93octane) if you are messing with ignition timing though.

I may have a secondary problem that's affecting me though...for some reason I am leaning out at high rpm. This is not a normal thing for a stock KA...usually richness is the problem.

I have been suggested to put an additional relay at the fuel pump to ensure 12V getting to it.

sticky_steve
Posts: 163
Joined: Sun Dec 24, 2006 12:27 pm
Car: 1991 300zx
2003 350z

Post

Well i re-drilled my cam gear for 2.5 deg of advance. So your saying that if i advance if i would lose hp. I thought that with 2.5 of adv, the lobe will open .8 deg after TDC and nissan spec is 1 deg after TDC. and with out advance i'm sitting 1.7 deg before tdc.

User avatar
alkemyst
Posts: 310
Joined: Tue Oct 28, 2003 5:46 am
Contact:

Post

sticky_steve wrote:Well i re-drilled my cam gear for 2.5 deg of advance. So your saying that if i advance if i would lose hp. I thought that with 2.5 of adv, the lobe will open .8 deg after TDC and nissan spec is 1 deg after TDC. and with out advance i'm sitting 1.7 deg before tdc.
It's shifting the rpm range, not really a loss of power.


sticky_steve
Posts: 163
Joined: Sun Dec 24, 2006 12:27 pm
Car: 1991 300zx
2003 350z

Post

So what to do you think about the 1.7 deg of retard. Your saying that with it retarded my power band is just a bit lower, but if i advance it 2.5 deg it will move it up a little. If thats the case then which do you think is better?

User avatar
alkemyst
Posts: 310
Joined: Tue Oct 28, 2003 5:46 am
Contact:

Post

retarding the cam will move the power band higher in the rpm range.

The problem is a lot of the info out there is just hearsay by people that really didn't do it which sucks.

All I know is on my particular setup adv had the power drop off at 5k or so, with the retard I was down a little until about 5k, but the power kept rising until redlne.

I am leaning out for some reason so it's killing my power overall though.

sticky_steve
Posts: 163
Joined: Sun Dec 24, 2006 12:27 pm
Car: 1991 300zx
2003 350z

Post

So your saying just leave it where its at. cause if i advance it may drop off at 5k.

User avatar
alkemyst
Posts: 310
Joined: Tue Oct 28, 2003 5:46 am
Contact:

Post

I am saying I am not sure ...it may be the 0 deg is the best. I have not tested it.

It could be something in my car working against me as well.

Bigvinnie
Posts: 1079
Joined: Thu Apr 07, 2005 2:07 am
Car: 2004 Nissan Frontier desert Runner, 2014 Nissan Titan

Post

alkemyst wrote:retarding the cam will move the power band higher in the rpm range.

The problem is a lot of the info out there is just hearsay by people that really didn't do it which sucks.

All I know is on my particular setup adv had the power drop off at 5k or so, with the retard I was down a little until about 5k, but the power kept rising until redlne.

I am leaning out for some reason so it's killing my power overall though.
O.K I will try to explain as simple as I can....Retarding an intake cam is good on power...... Cam timing is important in stroke 1. The down ward stroke which is what allows air and fuel to enter the cylinder chamber is critical... If you retard intake cam timing this will allow the cylinder chamber volume to become larger, to when the highest valve lift occurs. Larger volume will also cause a super charged effect to the chamber since the cam lift opened later in the downward stroke, the velocity of air entering into the cylinder chamber will increase. This is a syphon effect, where there is so much negative pressure applied before the valve opens it will cause a suction type effect.If the highest lift of the valve opens to early then you will only get les air entering into the chamber.......

As an example of why E pistons don't work in a DE engine without intake cam retard....



Most people that install the e pistons wether 89 or 90 pistons usually install the pistons without adjusting the cam placement. All this will do is cause the engine to make less power than the engine would using the stock de pistons at 9.5:1 compression ratio. Since the e pistons have a raised dish, volumetric cc's become smaller. This means if de cams are in stock placement, the raised dish pistons become less effecient in the downward stroke. Although the compression stroke is compressing air tpo fuel at a much higher rate, there is less air to say the least to compensate for stroke 1, this will ultimately just cause leaner A/Fr's, and a much more rapid drop in power, unless the intake cam is retarded to make up for the higher demand of air that is needed for the higher compression....

DE pistons are ultimately more efficient at making power in the down ward stroke since it's lowered dish only increases chamber cc volume to the point of where the intake valve will make it's highest lift.


sticky_steve
Posts: 163
Joined: Sun Dec 24, 2006 12:27 pm
Car: 1991 300zx
2003 350z

Post

So what your saying is the fact that my timing right now (1.7 deg retarded) is a good thing cause on the down stroke it will create a suction effect and when the valve opens, air will come rushing in. But if i advance it 2.5 deg which puts me at 0.8 deg advance (nissan spec is 1 deg advance) the valve will open just before the down stroke.

It kinda seems like if the valve opens late then not enough air will get in and dosent that defeat the purpose of having a longer duration valve. I understand that the down stroke will cause a suction but wont the valve still be open when the piston starts the up stroke which will cause the cyclinder pressure to go down or not enough compression in the cyclinder

User avatar
alkemyst
Posts: 310
Joined: Tue Oct 28, 2003 5:46 am
Contact:

Post

The problem is no one has posted a definitive answer on how a 248 cam lines up as intake.

In this thread and other people have posted the Intake Open spec is anywhere from 1.7 BTDC to 3.3 ATDC going with what someone says is the spec and how much it's adv vs retarded.

If the spec does end up at 0.8 ATDC with 2.5 deg advance that would require the Intake Open is 3.3 ATDC and Close is 68.8 ABDC giving .7 degrees of overlap.

Once this is advanced 2.5 deg you would have specs of 0.8 ATDC opening and 68.8 closing with a 3.2 overlap.


Bigvinnie
Posts: 1079
Joined: Thu Apr 07, 2005 2:07 am
Car: 2004 Nissan Frontier desert Runner, 2014 Nissan Titan

Post

alkemyst wrote:In this thread and other people have posted the Intake Open spec is anywhere from 1.7 BTDC to 3.3 ATDC going with what someone says is the spec and how much it's adv vs retarded.
I would say that anywhere to 1.75* BTDC is pretty close to being somewhat accurate to where the exhaust cam is placed on intake side. I haven't measured this myself , but I have spoken with several professional that have given me that estimate. I would say to make the best power you would want the vale to open at under 1 degree BTDC to 0* TDC.Once the range of valve opening is after 2* ATDC then there needs to be adjustments to the exhaust cam to make up for valve overlap.

User avatar
alkemyst
Posts: 310
Joined: Tue Oct 28, 2003 5:46 am
Contact:

Post

Bigvinnie wrote:
I would say that anywhere to 1.75* BTDC is pretty close to being somewhat accurate to where the exhaust cam is placed on intake side. I haven't measured this myself , but I have spoken with several professional that have given me that estimate. I would say to make the best power you would want the vale to open at under 1 degree BTDC to 0* TDC.Once the range of valve opening is after 2* ATDC then there needs to be adjustments to the exhaust cam to make up for valve overlap.
AFAIK there has been only one case where this setup was measured with a degree wheel and then the numbers we got back was a 'I think'...professional or not, the only way someone can know is to degree it.

I am debating what to try next...I am hearing lately fuel pump relays, but I have never heard about this in the past and you think if it was a needed thing it would be in all the FAQ's since for about $5 this would be a great mod if it was needed.

Outside of that either popping in my stock 232 cam or going 240/248 and taking out any question of what specs I am looking at. It seems the only real proven numbers we have is that dude Tre running full dist advance, extra fuel and 240(-7)/248(-5). This would put him at opening his intake at 8 degrees ATDC as well as running -9deg overlap.

At my website http://driftkat.com/240SXCamCalc.php I have a cam calc and I have the 248 Exhaust cam as an intake choice. You can apply advance / retard and see the specs. You can also enter your own numbers. Most of what's been posted though doesn't make a lot of sense once you run the numbers. Esp references to what advance and retard does to the actual cam timings.

Even in this very thread you have people posting things and tons agreeing that are in fact agreeing to something completely wrong.


Bigvinnie
Posts: 1079
Joined: Thu Apr 07, 2005 2:07 am
Car: 2004 Nissan Frontier desert Runner, 2014 Nissan Titan

Post

alkemyst wrote:
At my website http://driftkat.com/240SXCamCalc.php I have a cam calc and I have the 248 Exhaust cam as an intake choice.
My big problem is people using the 248 as intake of choice over the 240 cam....longer lift and duration cam should be used on the exhaust side, for higher reving and better scavaging numbers. When the longer duration and lift cam is placed onto Intake. The engine maybe intaking more air but using a shorter duration on exhaust only hinders scavaging which will overall defeat the purpose of high rev...An engine removes more heavy particulates from the exhaust.. Exhaust gasses are heavier than the weight of air that come in through the intake of the engine.

A good example of KA high rev cams would be PDM racings cams. With out changing the MAF and K value of the ecu the cams extended the RPM range an additional 2000RPM. Intake cam uses a shorter duration while exhaust cam uses amuch longer duration.

Personally I don't even understand why people waste there time with the worst KA cam spec known to nissan.... The 232........

sticky_steve
Posts: 163
Joined: Sun Dec 24, 2006 12:27 pm
Car: 1991 300zx
2003 350z

Post

It also makes sence what you are saying about having an longer duration intake and not enough duration for the exhaust. Almost as if some exhaust will remain in the chamber and get mixed in with the fresh air and fuel messing up the mixture.

So what cam spec would you use. 248/248 or what?

Bigvinnie
Posts: 1079
Joined: Thu Apr 07, 2005 2:07 am
Car: 2004 Nissan Frontier desert Runner, 2014 Nissan Titan

Post

sticky_steve wrote:It also makes sence what you are saying about having an longer duration intake and not enough duration for the exhaust. Almost as if some exhaust will remain in the chamber and get mixed in with the fresh air and fuel messing up the mixture.

So what cam spec would you use. 248/248 or what?
240/248 is the way to go. By far it has teh best placement of overlap. On non scv ka24de's 240/248 has showed the most power, with the longest power band.Now a 248/248 will show a much higher peak power than the 240/248 cam combo. but the indiference in scavging will probably drop a couple hundred RPM of rev from that combination.

Hype
Posts: 132
Joined: Wed Oct 23, 2002 11:32 am
Car: 93 240SX SE fb Super HICAS
Contact:

Post

Is this your opinion across the board, i.e. stock motors, motors with I/H/E boltons and turbo motors? The effects of say a well tuned header would have a great effect on scavenging. I would seriously donate some money if someone could go get some dyno work done to back up stated claims of powerband ranges for the different cams. I know there was one posted earlier but I would like to see stock vs 248/232, 240/232 etc.

[offtopic]Bigvinnie, I sent you an email regarding a post you made about S13 vs S14 KAs on s-chassis.com. If it got blocked in spam filter or whatever i'll make another thread here and we can discuss [/offtopic]
Modified by Hype at 3:52 PM 9/22/2008

Hype
Posts: 132
Joined: Wed Oct 23, 2002 11:32 am
Car: 93 240SX SE fb Super HICAS
Contact:

Post

edited for double post
Modified by Hype at 3:53 PM 9/22/2008

Bigvinnie
Posts: 1079
Joined: Thu Apr 07, 2005 2:07 am
Car: 2004 Nissan Frontier desert Runner, 2014 Nissan Titan

Post

Hype wrote: I know there was one posted earlier but I would like to see stock vs 248/232, 240/232 etc.

[offtopic]Bigvinnie, I sent you an email regarding a post you made about S13 vs S14 KAs on s-chassis.com. If it got blocked in spam filter or whatever i'll make another thread here and we can discuss [/offtopic]
I/H/E

Changing the K value with N60 MAF SAFC and some changes to fuel.I use the 240/248 cams and scvintake manifold, I haven't dynoed yet with my ported extrudede manifold but the rev and power range is much higher than it was when I used the SCV's.Power fell off after 6500 RPM so the graph was cut short to just peak power, but I can tell you I feel power clearly to 7000RPM.

I've given several other people the carbon copy of information to make this power and RPM rev range. So far all the people I know are happy with this set up, accept it guzzles gas really fast. I'm working on another SAFC setting that is more conservative and makes as much power if not better.

User avatar
gingerbredman
Posts: 543
Joined: Sat Jun 09, 2007 11:36 am
Car: 93 SE hatch, ~260k miles on the clock, 15" Enkei 92s, still stock. 2009 Sonata bouncing on Eibachs.

Post

alright, so i've looked through this thread time and time again, and now i think it's time for my 2 cents..

well, when i swapped my stock intake cam back in, it was tooth off (counter-clockwise), we rushed setting the dist. and reset it from 5btdc to 17btdc. the power up to 3500rpms kinda sucked, but there and above it was nice, it would actually break my GI-mongous tires loose when i hit 3500 in some cases

well, anyways, this isn't my theory, it's my experience, and based off it, i think i've come up with something.

it's quite obvious that the further counter-clockwise the intake cam is turned, the more top-end power is made, and vice-versa for low-mid range. well, i's thinkin about doing the dual-exhaust cam setup again on my new head, but this time rotating it say, 2 teeth?

would this work? why not? anyways, if the exhaust cam setup aforementioned doesnt work, i'll probably set up my stock cams the way they were before. wish there was a dyno around here

OH! one more thing, while my intake manifold's off, should i go ahead and remove the secondary butterflies? i've heard this and that, but if removing them won't hurt anything, i'll go on and do it.


User avatar
alkemyst
Posts: 310
Joined: Tue Oct 28, 2003 5:46 am
Contact:

Post

2 teeth may be cruising for bent valves....if you are looking to get really crazy it's time for aftermarket cams. If you do try 2 teeth ABSOLUTELY make sure you hand crank it a few times first.

Stick to the 4 tooth method and if you want to play with cam timing get/make gears.


User avatar
gingerbredman
Posts: 543
Joined: Sat Jun 09, 2007 11:36 am
Car: 93 SE hatch, ~260k miles on the clock, 15" Enkei 92s, still stock. 2009 Sonata bouncing on Eibachs.

Post

well, i ran with the dual exhaust cam setup for about a year. i never did rotate it 4 teeth counterclockwise either. i never even looked at the dist. timing either.

tack on another 1000 miles after i got the intake cam back in and the dist. timed. the int. cam was even still a tooth off soo.. seems like it takes a lot to hurt these valves..

i'll probably just keep everything stock, im just brainstorming. besides, with the stock int. cam 1 tooth ccw, cruise control and passing just sucks..


Return to “KA24E / KA24DE Forum”