Power loss?? - 248/232 cam swap

[sidewayz240]

I just did the S13 248 exhaust cam swap on my S14. The car dyno'd at a healthy 141whp before the swap, the 248 was put in with 2.5 degrees advanced (redrilled sproket) and rotated 4 teeth CCW.

After the swap the car started up fine and sounded good. We dynod the car once more and the results were quite dissapointing. The car lost a whole 20whp. It dynod at 121whp.... Wtf?

The only problem we could think of is that when we rotated the cam four teeth CCW we counted the tooth we were on as 1 (one), and counted three over from there. So we opened her back up and moved it one more tooth CCW. Now the car wouldnt even start, intake side was opening way to early.

Anyone that has done the swap have any input on what went wrong? Any ideas what so ever??

Thanks

[project-D180]

any one??im curious

[Gorilla Unit 33]

ok well i know if you have an S13 and you swap the 248 cam in (the intake side) you clock it back 4 teeth. Now im not so sure if you swap out your S14 exhaust cam for the 248 that you would do the same. For the simple fact that on the S13 you clock back doesn't necessarily mean you clock back for the exhaust side when you do the swap on the S14 head.

Edit: i cant find a write up about just installing a 248 on just the exhaust side.

[Dousan_PG]

i dont haev any info
but what is the point of this swap? why not go w/ 256? im curious..thanks :)

[GunmetalSR]

i dont haev any info
but what is the point of this swap? why not go w/ 256? im curious..thanks :)
that would be an aftermarket cam
the 248 came stock in the s13 so its pretty cheap to do

[BigVinnie]

I know for a fact that the 232 on exhaust is garbage (it shortens the powerband). The 248 will never open 1 degree prior to TDC either unless you have an adjustable timing gear. Thats 2 problems that need to be corrected.

Because exhaust ports and exhaust valves are typically smaller you will want to use a much longer duration cam on exh in order to pull power further into the RPM range. Or you will want the exh cam equal to the intake cam which will make it a midrange performing engine. Using the 232 on exhaust, could account for almost 60% of your power loss on an OBD1 engine. The other 40% can be accounted for that the 248 will not line up perfectly 1 degree prior to TDC.

the only way it will line up perfect other than buying the NISMO 248 is getting a JWT adjustable timing gear.

[Dousan_PG]

that would be an aftermarket cam
the 248 came stock in the s13 so its pretty cheap to do

duh
most aftermarket cams bolt in like stock cams as well. even s14 ones retaining that ncvs or whatever it is.
is it the cost factor? or are there any real gains?

[GunmetalSR]

duh
most aftermarket cams bolt in like stock cams as well. even s14 ones retaining that ncvs or whatever it is.
is it the cost factor? or are there any real gains?
out of the s13 cams?
yea there are some gains and a very slight lobe
this is a good and cheap way to make a little extra power but stay somewhat factory

[sidewayz240]

Wow revival.

I ended up ditiching the 248 exhaust swap because of a couple reasons, most of which big vinnie mentioned. In redrilling the cam gear, theres just too much room for error, a little bit off makes quite the difference. Its not the great awsome swap it was originally thought to be.

I got myself a set of stock S13 240/248 cams and threw those in and was very impressed with the results. Ended up making 10 more whp and similar torque, not too shabby for a $20 set of cams eh? 151 whp in the end.

Every S14 ka owner should do this, its a direct swap, no need to worry about redrilling or counting teeth and costs next to nothing if you do the swap yourself. Best bang for the buck no doubt.

[BigVinnie]

What people don't realize about the OBD2 engines is that it uses a larger MAF than the OBD1 KA's. So right off the bat you should just know that installing OBD1 cams exactly they way they come in OBD1 engines will make much better power gains.

So when you see the 2 engines in comparison making the same stock power output. One is using crappier cam selections because of it's larger MAF. The OBD1 cams will pull power further in the RPM range and make more power than it would for an OBD1 engine with the smaller MAF. Kind of a no brainer.

[Matej]

My car has this. Not sure if it made any difference because I have never been to the dyno, but apparently it is supposed to increase low and mid-range power/torque. However, I never drilled any sprockets or anything, too scared to do that.

[initial_drifter]

We tried this at the shop and it turned out that it killed the power

it feels faster in the upper end cuz there's nothing in the lower.

I'll try to find the dyno sheets but we lost 9 hp and the only thing that changed was the powerband.

IMO, it's not worth it.

[project-D180]

what about 5 teeth counter clock or putting the 248 in stock 240 position?do u think that would work?since i jus got my motor back together with no intake on yet i think im goin to test out different tooth setting and turn it by hand and see how it turns out with out bendin vavles

[Flybert]

duh
most aftermarket cams bolt in like stock cams as well. even s14 ones retaining that ncvs or whatever it is.
is it the cost factor? or are there any real gains?

Aaron, they are talking about KA's, not SR's.

[let5l1de]

What people don't realize about the OBD2 engines is that it uses a larger MAF than the OBD1 KA's. So right off the bat you should just know that installing OBD1 cams exactly they way they come in OBD1 engines will make much better power gains.

So when you see the 2 engines in comparison making the same stock power output. One is using crappier cam selections because of it's larger MAF. The OBD1 cams will pull power further in the RPM range and make more power than it would for an OBD1 engine with the smaller MAF. Kind of a no brainer.

The larger MAF was one reason why I decided to go OBDII. Well that and wanting to make some power with OBDII when everyone understandably goes OBD1.

My 89 coupe has a nicely built 95 OBDII s14 KA24DE assembled by myself. This engine pulls amazingly hard with all the mods I have done and yes, the stock S13 cams are in with no timing mods. I noticed a nice difference in the 3000 rpm range all the way up to 6500, over the s14 232 cams. Dyno to come soon. maybe even a s13 to s14 cam comparison.

FYI just passed state ref smog test with all the mods as well. yay for the sticker! boo to it saying non-turbo...

~mario

[project-D180]

curious will the stock ecu work with a n60.n62 maf?

[BigVinnie]

curious will the stock ecu work with a n60.n62 maf?


no.............................

[let5l1de]

curious will the stock ecu work with a n60.n62 maf?

In this case, No.

The ecu should always be calibrated or a safc should be added to whatever engine mods you have performed.

(a stock ecu that has been properly re-tuned will work)

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beat me to it BigVinnie