J-spec cams (exhaust worth it?) Opinions please.

[PR5Matt]

I am looking to do a mild build (the only parts to add now are a modified intake manifold, some sort of ECU or tuning by JET, UDP (ordered), and cams, and I want to go with the J-spec cams for drivability as well as stay stock compression for cheap gas. These cams should do me fine, but look ing at the specs I am wondering if my money would be better spent on just the intake cam and then get cam gears and tune it with the stock exhaust cam. Any opinions?

 

[Mike R]

Been asked alot. You'll need more exhaust than intake though.

 

[twilightprotege]

^ yep, you need more exhaust than intake.

and dont worry too much about drivability. i have larger cams on both sides (far larger on the exhaust side) and my car idles like stock (except for the bit extra vibration)

 

[PR5Matt]

Well the reason I asked is that many 16valve 4cyls need more intake cam because of the intake to exhaust flow relationship. It sure would be nice to know the flow numbers of our heads stock!

BTW anyone know where I can get the j-specs the cheapest?

 

[twilightprotege]

our heads flow much better on the intake side. for NA especially, what you suck in you need to be able to push out, which is why we need far bigger exhaust cams.

a cam the cheapest - 2nd hand on here

 

[00RedProtege]

I have installed the J-Spec intake cam. Just doing one will will increase hp some but doing both w/cam gears will give you better gains. I would recomend getting both if you cannot find better cams.

 

[n2o99civicsi]

The only reason you'd need a hotter exhaust cam is if you go turbo. If you are on a budget, you'll notice nice gains with just the intake, the exhaust won't blow you away with numbers...
Getting both is nice, especially with gears for tuning, but you really only need the intake for a mild build up.

 

[twilightprotege]

an exhaust cam is definately needed! we're talking about a head which flows 20% more than the exhaust side and you're saying only upgrade the intake cam? talk about low VE ratios...

for the most potential out of the FS head, a big exhaust cam is needed to get high VE numbers

 

[PR5Matt]

An engine with an exhaust that flows 80% or more of the intake can take well to more intake camming or equal camming. When it gets in the 75% and below range then go more for exhaust.

At least that is they way things are in the V-8 world.

Again, without solid flow numbers it is hard to make a proper choice.

BTW more exhaust can help with FI, but you are better off building for N/A power first (within compression and timing constraints) and then add FI. That way you can run less boost to get the power you want.

From experience, nitrous and blower cams are dogs compared to a good N/A cam even on boost or the juice. (I've seen guys pick up a bunc of ET and power by ditching those kinds of cams for good N/A cams).

 

[PR5Matt]

Let me clarify.

All I want is more rev-ability and a little better powerband. This is my work car so I don't need to shock the world or anything. I just want better feel and again, a more usefull powerband. There does not have to be any earth-shattering gains.

Will the intake do that for me?

 

[akhilleus]

yes the JDM will show gains. Although when I had it installed i wasnt very impressed. Personally to make it worth it you should just do both.

 

[PR5Matt]

Shane Racing is the only place I have found both, and I heard that they aren't very reputable.

 

[twilightprotege]

yes please dont buy there. i have no idea about their reputation, but they are rip offs! have a look at the "Mazda Protege Stainless Header" for sale....me thinks that's an obx....for $599 on sale LMAO!!!! 321 being the highest quality SS? close...i dont even know if 321 is a type of SS! 316 is the best grade...i could go on......

 

[PR5Matt]

Yea, never heard of 321. Oh well... I guess it is just the intake until I can find more out about the Wagners or order some custom.

 

[MsProtege]

Let me clarify.

All I want is more rev-ability and a little better powerband. This is my work car so I don't need to shock the world or anything. I just want better feel and again, a more usefull powerband. There does not have to be any earth-shattering gains.

Will the intake do that for me?

You answered your own question! Its obviously better to go bolth, thats for sure, if you want to budget and be safe, get the intake, see if the gains are acceptable and if not go for the exaust cam, and still if not then get cams gears and tune, or headers, WHAT EVER, just keep going untill you feel its right.

SO WHY ASK "Would it be better to tune with the stock exhaust cam?" when its OBVIOUSLY BETTER TO UPGRADE! Its never " Better" to tune with stock then better j-spec parts. It's all a mater of weather you feel the gain is adequite or not!

 

[PR5Matt]

You answered your own question! Its obviously better to go bolth, thats for sure, if you want to budget and be safe, get the intake, see if the gains are acceptable and if not go for the exaust cam, and still if not then get cams gears and tune, or headers, WHAT EVER, just keep going untill you feel its right.

SO WHY ASK "Would it be better to tune with the stock exhaust cam?" when its OBVIOUSLY BETTER TO UPGRADE! Its never " Better" to tune with stock then better j-spec parts. It's all a mater of weather you feel the gain is adequite or not!

Yeah I know, but "...is the j-spec exhaust worth it over the stock cam?" is the question. If it was truly better than there would be consensus.

I would go both if I felt it was worth it. If the j-spec is not, then cam gears are much easier to install and tinker with than the cams. IMHO.

Now if this was an all out build, then I wouln't have asked all of you guys for your opinions. I know what to do...

BTW, thanks for your responses guys!