Supporting mods for cam swap

[tlip93tsi]

I am about to install a set of webcams "street" cams, and crower springs/retainers and i was wondering what kind of supporting mods I would need to go with. BTW, my engine is stock.

 

[rdrkt]

Why would you put cams on an otherwise stock car?

 

[tlip93tsi]

because i blew an exhaust valve and had to take the head off to fix it. I have been told all sorts of stuff from different people, and most seem to agree that it is ok to run slightly more aggressive cams, but i will need to increase fuel flow. None of the people i have talked to could be called experts though, and none of them have experience w/ this engine.

 

[tlip93tsi]

also, i haven't actually purcheced these items yet, and i was planning on doing a mild porting of the head, I have intake, but unfourtunatly still stock exhaust. Am i gonna run into problems?

 

[nothing stock]

Its a total waste with the stock turbo to install retainers/springs. Until you have a turbo that can hold full boost past redline you don't need stiffer springs or lighter retainers. The cams don't require any supporting mods, your just going to get worse idle, and worse gas milage. You might get a little more top end if your on a 14b, but none if your on a T-25.

 

[tlip93tsi]

thanks for the feedback, I am new to the turbo world and it seems like my questions are dumb to all of you so thanks for bearing with me. also, would i benefit from a mild port job or should i just save that for later?

 

[Big Woo]

Not true, If you think about it . The WEBCAMS street grind "will" provide more lift and duration than the stock cams, thus allowing more time for the intake charge to fill the cylinder. This will have a bigger effect when larger turbos are used, but they will make more power than the stock cams even with the stock turbo. However since you said that your car is stock, you would be further ahead by putting your cam money toward an after market exhaust system. Of corse if money is not a problem then go ahead. IMO there is some merrit in doing the cams now since you already have the head off the car. It may save you some time and money later.

 

[G-Ell]

I could see maybe getting an angled valve job and stornger retainers so your motor can handle +6000 better, but cams + feul mods are a really large "might as well" for just a broken valve. The stock head + cams will do you good for a long time.

 

[sunflashx]

Swapping the cams with the head on the car is easy, changing springs and retainers on the car is a much more of a PITA than with the head off the car. If you intend to do them at some point in time, I'd do them while your in there now.

 

[rdrkt]

Originally posted by Big Woo
Not true, If you think about it . The WEBCAMS street grind "will" provide more lift and duration than the stock cams, thus allowing more time for the intake charge to fill the cylinder. This will have a bigger effect when larger turbos are used, but they will make more power than the stock cams even with the stock turbo.

Hey guess what I thought about it your WRONG! Take a look here this is the before and after with the web cam street grind on the RRE website. Notice the power loss all the way up to about 4300 rpms? There is no appreciable gain in power until about 6200 rpms. The 14b would have lost steam a long time before that and you wouldn’t make any power that high in the rpm band. So for this kids entire power band he would have LOST power. Not to mention the fact that he would have to deal with all of the idle issues that would need to be resolved with a safc that he doesn’t have. The real reason to switch to cams is so that you don’t lose as much power AFTER 6k this is only required if you have a turbo that can make power well past that point.

So Big Woo next time why don’t YOU think before you comment.
:xnuts:

 

[Big Woo]

Well without seeing a dyno plot with the Web cams a stock engine,and a 14b we will not know for sure. The Web cams will still provide a power increase over the stock cams. Although as I said he would be further ahead to spend that money on an exhaust system, or something. One dyno plot for a modified car hardly compares to a bone stock DSM with a K&N.

So rdrkt I see you can read what I wrote, but you did not comprehend want I said, and your a wiseman:laugh:

 

[rdrkt]

Originally posted by Big Woo
Well without seeing a dyno plot with the Web cams a stock engine,and a 14b we will not know for sure. The Web cams will still provide a power increase over the stock cams.

Well gee if you want to be that picky I guess we will never know for use until we hit HIS car with a before and dyno graph. Look at the graph again sparky this is a 16g powered car a 14b will more than likely make less power most of the way through the powerband. Aftermarket cams will only show a power INCREASE after certain RPM point up until that point they will more than likely LOSE horsepower. This will be even more accurate in a near stock car.

I will reiterate this ONE more time just for you. Web “street” cams (which I have owned BTW) wont show an appreciable gain over stock cams until after 6k. A 14b would be losing power BEFORE 5k. So that would mean he would make LESS power over the ENTIRE powerband.

It doesn’t take a wiseman to realize this. What is your problem?

Originally posted by Big Woo
but you did not comprehend want I said, and your a wiseman

It is comprehend WHAT I said and YOU’RE a wiseman Good job buddy

 

[Big Woo]

Well I don't think I am being picky. Do you think that no other camshafts will make more power than the stock ones in a stock engine? I do understand that the powerband will move up the rpm range as camshaft duration increases. I also looked at the graph and it shows a small increase in power in the upper rpm ranges with a 16g. There are however other factors such as since the 14b will have trouble keeping up "air flow wise" having a larger intake camshaft may allow for better cyilider filling than the stock cams in the upper rpm ranges with a 14b turbo. Also altering the cam timing cam cause changes in the effictive powerband. Like advancing the intake cam will tend to make engine respond earlier in the rpm range, while giving up a little bit at the top. It will also decrease the overlap period, and close the intake valve sooner thus building a little more cylinder pressure than if the cam was installed straight up. That could also be coupled with retarding the exhaust cam, and further reducing the overlap period. Of couse this could go no forever, and there are always tradeoffs, but generally decreasing the overlap with help the engine make more power at lower engine speeds. Also of note is at what posistion the cams are installed the graph makes no mention of that I have installed many of camshafts, some fall right in some require adjustable gears, or offset bushings, to get the timing right. Since we don't know where the cams were set, and differnt dyno runs at differnt camshaft posistions, we do not know if this is as good as it gets for a set of web cams and a 16g. We are getting way beyond the original question. The awnser is it depends on who you ask.

 

[rdrkt]

Originally posted by Big Woo
Do you think that no other camshafts will make more power than the stock ones in a stock engine?

I don’t think any cam worth keeping will make more power on a stock car. Even a pair of HKS 264s would more than likely lose power through most of the band over stock.

The point is not to show a marginal gain in overall hp but to create a bigger better powerband. Even on that graph you can see how peak gains are under 15hp but it makes 40hp more than the stock cams at a certain point on the rpm band. It is still giving up 15 or so hp for a decent chunk of the low end. The point is that the increase in top end will be worth the reduction in low end. However a 14b will mostly make it power on the low end and midrange and that is where all the losses from the cams will be. The top end wont make up for it in that situation because the turbo will be long out of steam where the cams start to make the difference in power.

Originally posted by Big Woo
I do understand that the powerband will move up the rpm range as camshaft duration increases. I also looked at the graph and it shows a small increase in power in the upper rpm ranges with a 16g. There are however other factors such as since the 14b will have trouble keeping up "air flow wise" having a larger intake camshaft may allow for better cyilider filling than the stock cams in the upper rpm ranges with a 14b turbo. Also altering the cam timing cam cause changes in the effictive powerband. Like advancing the intake cam will tend to make engine respond earlier in the rpm range, while giving up a little bit at the top. It will also decrease the overlap period, and close the intake valve sooner thus building a little more cylinder pressure than if the cam was installed straight up. That could also be coupled with retarding the exhaust cam, and further reducing the overlap period.

The problem with this is that the 16g also has trouble air flow wise in a stock engine. The 14b would just start losing power a lot earlier. Yes cam timing CAN have a SMALL effect on hp but from what I have seen from a lot of other DSM guys dyno charts cam timing changes produce minimal gains at best. You would also have to factor in the additional $600+ for cam gears.

Originally posted by Big Woo
Since we don't know where the cams were set, and differnt dyno runs at differnt camshaft posistions, we do not know if this is as good as it gets for a set of web cams and a 16g. We are getting way beyond the original question. The answer is it depends on who you ask.

I cant believe you are still arguing. But hey whatever you just wont accept the truth that’s fine. Don’t just look at the RRE graph do some research on the HP gains that people gain on cams and at what point they make there power. I am DONE with this thread. I’m ready to let it die.

 

[tlip93tsi]

Wow, i don't check my thread for two days and it turned into a f*#@&ing war! i think im gonna keep the head stock because i dont wanna break anything.

 

[Kevin Jewer]

I cant understand why poeple keep saying a 14b loses power after 5k rpm. And it runs out of steam at 18 psi, etc etc... Its all bullshit. Anyone running 12s on a 14b is running 22-24 psi, just like I did.

As for the cams, I took before and after datalogs when I installed HKS 264/264. If you overlay the airflow per revolution graphs I picked up airflow everywhere from boost onset to 7800 rpm. Sepcifically .3 grams per rev at 7k, and .2 grams per rev at 3500 rpm. More air is more power. I felt NO loss in low end at all. Now I didnt dyno it, and I dont have web cams, so YMMV. Just some of my observations.

To the orignal question, stock cams run 11s, so just keep that in mind when planning your upgrade path.

 

[Big Woo]

"argue" no just trying to share some information. It is obviousl that we have differnt opinions on this subject. I have built many engines for DSM's using cams from HKS, WEB, Crower, and even a custom inverse radius grind from Reed.

I thought that if someone has a plan to upgrade thier car, but found out they had to fix a burned valve or something first I.E. fix a major mechanical problem prior to doing upgrades. That that person may save money, and or time by doing some of these wanted internal mods during this time. Yes it does very from the normal upgrade path, but that does not make it wrong.