Question regarding BC 272 cams. Do I need adjustable cam gears?

[ziggys95tsi]

My friend is installing them tomorrow and Im just wondring If i can set them to anything to maybe see some performance changes. I have DSMlink and can tune that decently so should I just leave them be or maybe advance or retard a little to get some more power. ?Also can they be changed when on the car incase the engine doesn't perform as well ? They are the Adj. Fidanza gears and any help from anybody maybe with some experience would be appreciated!!!!

 

[Spln_Hrd]

I would retard the exhaust cam about 2.5 degrees, regardless of getting it on the dyno. Our engines have less valve overlap than they need for a higher flowing setup. Mitsu set them this way for emissions purposes.

I took a protractor and drilled a new hole in the exhaust cam that set me 2.5 degrees retarded. This was BY FAR the best FREE mod I have ever done, it made a huge difference in the power in the 6-7k rpm range.

This extra valve overlap has its downsides though, you will have less vacuum and the car will not idle as good, but I like it and so does dsmlink(the hp guesser built into it)

I also have adjustable cam gears for my new setup and I will be setting mine at this point as soon as my engine is broke in.

 

[ziggys95tsi]

My Engine has the 1mm oversized valves. Would that change the number any bit??? Also did you change your intake one as well??? thanx for your input

 

[Defiant]

I did not read this entire thread. However, adjustable cam gears will be good for around ten horsepower on any car, in the hands of a competent mechanic who will put the effort into properly setting them. In the hands of a randomly-guessing oaf, they can lose at least that much.
Moving the torque curve is another capability of camshaft timing adjustment; you can look at your output as being a bottle of water on a hot day- you can drink it all in the morning, sip it all day, or wait until evening to have a slaking drink after a day of thirst. But it won't do much to make the bottle bigger.
There can also be aspects to cam tuning which will do more to feed the characteristics of a turbocharger- you may want the exhaust energy to be released at a different time than you do on a normally-aspirated engine, exchanging power production in the combustion chamber for more/better/quicker spoolup characteristics by management of when and how much of the exhaust energy is admitted to the turbine.
Studying camshaft timing will show you in quite short order how the stupid, virtually prehistoric devices are the second-biggest loss of energy potential after the engine's cooling system. One fine day, we may actually have electronic valve control and actuation, and the god-forsaken pieces of troglodyte guesswork which camshafts are will be up on the shelves with carburettors.

http://www.dsmtuners.com/forums/showthread.php?t=221200
And especially:
http://www.dsmtuners.com/forums/showthread.php?t=17110

 

[96gstdsm]

Thank you all very much for all the info. One thing I am still not sure on. If I do go with the 272's without adjustable cams where is the power going to be with those? When people say it is good for the high rpm's, how high are we talking about? I am coming from a t25 turbo. Will my lower and mid range power be less than before or still a lot more power there and then crazy more power up high? I am talking about the addition of the big 16g also making the power not just the cams here.
If I do get adjustable cam gears with these cams and I retard the exhaust cam, how much can I adjust the power to the low to mid rpm range? This being strictly a daily driver is seems that having the power only up high will not be nearly as much fun.

So the main thing I want to know is:

What rpm's is most of the power going to be at?

How will the low to mid range power be compared to how it was with my t25?

How much with adjustable cam gears can my power range be adjusted?

 

[dsm-onster]

I would retard the exhaust cam about 2.5 degrees, regardless of getting it on the dyno. Our engines have less valve overlap than they need for a higher flowing setup. Mitsu set them this way for emissions purposes.

I took a protractor and drilled a new hole in the exhaust cam that set me 2.5 degrees retarded. This was BY FAR the best FREE mod I have ever done, it made a huge difference in the power in the 6-7k rpm range.

This extra valve overlap has its downsides though, you will have less vacuum and the car will not idle as good, but I like it and so does dsmlink(the hp guesser built into it)

I also have adjustable cam gears for my new setup and I will be setting mine at this point as soon as my engine is broke in.

Amen! I had great results, too, way back when I had stockers. Some good results from retarding exhaust cam

Studying camshaft timing will show you in quite short order how the stupid, virtually prehistoric devices are the second-biggest loss of energy potential after the engine's cooling system. One fine day, we may actually have electronic valve control and actuation, and the god-forsaken pieces of troglodyte guesswork which camshafts are will be up on the shelves with carburettors.

Also an amen from me.

If I do get adjustable cam gears with these cams and I retard the exhaust cam, how much can I adjust the power to the low to mid rpm range? This being strictly a daily driver is seems that having the power only up high will not be nearly as much fun.

You'll have to start retarding and log. You'll see the best airflow curve for your goal and your setup.

 

[96gstdsm]

How bad is the low to mid range power with 272's out the box and no adjustable cam gears? Will I just hit full boost much later? What are the rpm's that would shine? Being a big 16g will the turbo be able to hold up with the cams? Or will the boost die out while the cams are gaining? This being a daily driver I am not doing cams simply to get the most peak hp or to have the faster 1/4 mile time. I am looking for a fun daily driver with very nice power and not laggy.
Are the 272's not a good choice for what I want? How are the stock cams with a big 16g turbo?

 

[dsm-onster]

How bad is the low to mid range power with 272's out the box and no adjustable cam gears? Will I just hit full boost much later? What are the rpm's that would shine? Being a big 16g will the turbo be able to hold up with the cams? Or will the boost die out while the cams are gaining? This being a daily driver I am not doing cams simply to get the most peak hp or to have the faster 1/4 mile time. I am looking for a fun daily driver with very nice power and not laggy.
Are the 272's not a good choice for what I want? How are the stock cams with a big 16g turbo?

The most fun my car ever was: small 16g, stock cams, and LOTS o' boost! like 25 psi on that small compressor! It was fun and I retarded my exhaust cam gear 3 degrees and it was even more fun. W/ a beautiful, lopey idle.

You're mid range will not suffer. Just your low end. Many report that the low end is not even that bad. If there's more lag, downshift or stay in the gear. I think 272s deliver a wider power band than 264s or even stock cams. It is higher but WIDER. Meaning more rpms in at good VE.

As I've stated, "a fall off in boost is not the same as a fall off in power." You can fall off in boost and still be making more horsepower. Falling of in boost simply means that the engine is capable of sucking more power out of your turbo. You will reach a limit of deminishing returns. But likely not on a pump gas tune, w/ pump gas boost.

 

[96gstdsm]

The most fun my car ever was: small 16g, stock cams, and LOTS o' boost! like 25 psi on that small compressor! It was fun and I retarded my exhaust cam gear 3 degrees and it was even more fun. W/ a beautiful, lopey idle.

You're mid range will not suffer. Just your low end. Many report that the low end is not even that bad. If there's more lag, downshift or stay in the gear. I think 272s deliver a wider power band than 264s or even stock cams. It is higher but WIDER. Meaning more rpms in at good VE.

As I've stated, "a fall off in boost is not the same as a fall off in power." You can fall off in boost and still be making more horsepower. Falling of in boost simply means that the engine is capable of sucking more power out of your turbo. You will reach a limit of deminishing returns. But likely not on a pump gas tune, w/ pump gas boost.

Will the 272's even make more power that I will be able to use seeing as how I have a 16g? Meaning will it really mainly show gains over 6 or 7k rpm's? Being my daily driver I wont even, when getting on it, normally rev past like 5 or 6 for sure. Will it spool up for sure slower than if I were to be on my stock cams?
Also I am doing all my upgrades at once. Going from t25 to new engine and new turbo and fuel and basically all stage 2 mods. Will the mid range still seem much better than before? Or would it be similar but just much better high end? I am basically doubling my whp with all this so figure it will be crazy power.(atleast for me)

Would 264's improve the low and mid range much more than the stock cams? Would it hit harder than the stock ones? Would the top end power be worse than if I had the stock cams?

Sorry if I am kinda asking the same questions here, jut really not quite understanding what the power curve will be like compared to my old set up and also compared to new setup with or without the 272's.

Also when you are talking about it's good for high rpm power, what is the rpm range we're talking about? Like 6k or higher or what? Will I not really see much power till like over 4 grand? I am coming from the slow t25 and I loved that it hit right away, made it a lot of fun even though that turbo sucks any higher.

EDIT: So for fun not caring about which gives me higher hp numbers. Would it be a decent idea to just use stock cams and get 1 adjustable cam gear for the exhaust cam and retard it?

 

[Calan]

One fine day, we may actually have electronic valve control and actuation, and the god-forsaken pieces of troglodyte guesswork which camshafts are will be up on the shelves with carburettors.

I'm surprised one or two of you "old DSMer's" haven't done this yet. Surely all it would take is a few ten thousand $ worth of mil-spec valves and components and a some free time..

 

[dsm-onster]

Will the 272's even make more power that I will be able to use seeing as how I have a 16g? Meaning will it really mainly show gains over 6 or 7k rpm's? Being my daily driver I wont even, when getting on it, normally rev past like 5 or 6 for sure. Will it spool up for sure slower than if I were to be on my stock cams?
Also I am doing all my upgrades at once. Going from t25 to new engine and new turbo and fuel and basically all stage 2 mods. Will the mid range still seem much better than before? Or would it be similar but just much better high end? I am basically doubling my whp with all this so figure it will be crazy power.(atleast for me)

Would 264's improve the low and mid range much more than the stock cams? Would it hit harder than the stock ones? Would the top end power be worse than if I had the stock cams?

Sorry if I am kinda asking the same questions here, jut really not quite understanding what the power curve will be like compared to my old set up and also compared to new setup with or without the 272's.

Also when you are talking about it's good for high rpm power, what is the rpm range we're talking about? Like 6k or higher or what? Will I not really see much power till like over 4 grand? I am coming from the slow t25 and I loved that it hit right away, made it a lot of fun even though that turbo sucks any higher.

EDIT: So for fun not caring about which gives me higher hp numbers. Would it be a decent idea to just use stock cams and get 1 adjustable cam gear for the exhaust cam and retard it?

Both 264s and 272s will 'come on' later than stock cams. My FP2X cams (like 272s w/ a bit better ramp rate and one degree lower duration) hit at around 4K. They don't feel sluggish at the lower rpms. They feel like stock cams at those rpms. The higher lift and better ramp rates from upgrading cams give you power at any rpm. So this is how cams w/ a duration that favors a higher rpm than stock cams can still perform like stock cams at the lower rpms. Almost all report no loss in low end when swapping to 264s. Many (including me), feel the slight loss in idle to 2K rpms is worth it. And the cams are more fun on the street because they still perform like stock from 2-4k and then there's the huge "kick in the pants" at around 4K.

Stock cams have been shown to be rather versatile. If you look at the lobe centerline angles, you'll see there is little to no overlap. This really helps in the upper rpm ranges. this makes up for the fact that duration of all stock cams are very conservative and designed for a torquey factory new feel. Retarding the stock exhaust cam causes a small turbo to hit REALLY hard. I didn't "feel" a loss up top until I upgraded to an 18g and that was because I was paying attention and wanted a turbo that held to redline. This is much bigger than a big 16g. I did not 'notice' any more drop off w/ my small 16g than w/ stock cam timing. This will likely be your result too.

Another real cheap option for a performance cam upgrade was mentioned in my old cam retard thread: non-turbo exhaust cam. Basically, get a 1G n/t exhaust cam and install it retarded exactly 1 cam sprocket tooth. and you're right where retarding a stock exhaust cam 1/2 tooth would be.

I just realized you have a 2G and have a more cam timing retard dialed in both cams. Retarding the stock exhaust cam may do nothing for you. Likely advancing the stock intake cam will yield better results for spool. But I havn't mucked w/ 2g cams. And, I have no experience on how the 2g head ports and intake manifold will affect cam timing events. Almost all the 1g guys see good results. But not all 2g guys do. Since your stock cams come w/ a little more duration than 1G cams, I don't know if there is a better upgrade for you other than simply buying performance cams or performace regrinds. I'm throwing this in to say that I KNOW 1g cams. And particular cam profiles respond VERY differently to particular dialing. A certain timing for one cam profile may yield the opposite results for another profile.

If you're THAT concerned about off idle to 3K performance and don't plan on upgrading the turbo, just get a set of adjustable cam gears and monkey w/ those until you get a good feel. Otherwise, I'd skip the 264s/fp1s and get a set of 272s/fp2s I don't think there's that much difference in idle quality and midrange. But you'll have way more cam if later you decide to upgrade the turbo.

 

[chrisb33]

Sorry for hi-jacking this old thread.

Im about to rebuild my long block in the next couple of months and im now listing down my parts list. So far this is what i have in mind:

1. stock 1g 7 bolt internals with new 2g pistons and rings and ARP rod bolts
2. clevite main and rod bearings
3. ARP head studs
4. Cometic head gasket
5. Magnus Fuel rail
6. BC Valve springs and titanium retainers
7. FP18g
8. Fidanza lightened flywheel and clutch kit 3.2

other mods are already listed on my profile.

This will be mainly be used on the streets and not for drag.

my question is - is it a good investment to get cams? and cam gears? im thinking of getting the BC 272/272 and fidanza cam gears?

TIA.

chris b

 

[96gstdsm]

I would do it. I really liked the 272's with my 16g even. I have hardly driven it since my whole build since I have had idling problems unrelated to the cams.
The top end is awesome. It does not stop pulling at all!
You have a bigger turbo then I went with as well, so I would think it would be a perfect setup.
Like everyone here said you can retard the exhaust cam to move the power around a little if desired.

 

[96gstdsm]

Nice decision. Post back once you get them put in. I'm sure you'll love how they just keep pulling up top!

 

[chrisb33]

Will do. Im just worried about taming these cams coz it might lead to idling problems.

Anyone have issues on idling with cams? if so, how were you guys able to "tame" your idling?

TIA

chris b

 

[dsm-onster]

"Taming". ??? 272 cams can idle at the stock idle speed. . .

If the slight lope is too much for you, then why bother modding a car .

 

[chrisb33]

"Taming". ??? 272 cams can idle at the stock idle speed. . .

If the slight lope is too much for you, then why bother modding a car .

Sorry maybe "taming" isn't the right term I'm supposed to use anyway, i definitely dont mind the slight lope.

I going with the BC 272/272's and the fidnaza cam gears. Thanks a bunch guys.

chris b