I have been around for quite some time with these cars and never saw anyone post up the biggest cam they have seen used with the stock valvetrain.

I am insterested in this because I am going with bigger cams here soon but do not want to upgrade my valvetrain just yet. I will eventually go with the revolver setup for big power with my turbo.

So my question would be what is the biggest cam you have seen used with the stock valvetrain that doesn't push the valvetrain over the limit of its design?

I autocross/drag race the car and the motor see's nothing past 7,300 RPM. What would be the biggest cam I could put in while still keeping the stock valvetrain? (For now)

~Zach

 

If the motor doesn't see more than 7300rpm, then the 'biggest' isn't necessarily the best.

The stock head ports are relatively dead above ~10.2mm or thereabouts, so 'bigger' lift isn't going to be of much help regardless of what valve springs are used.

Where duration is concerned, 'bigger' isn't always better, depending upon the power characteristics. The GSC or HKS 280s are technically the 'biggest' duration-wise of cams that are friendly to the factory valvetrain, but a shorter duration cam (e.g. GSC or HKS 272) is better suited to your rpm range. Then again, I might mention that with a set of cam gears, a bit of LC/LSA trickery may be of further benefit.

 

like Ted B said, biggest in regards to lift, duration or a combo of the two? With a 2.3l stroker and GT35R on xede tune with stock valvetrain, get the S2's from GSC. You might suffer a bit at idle, but if you have the capability of setting the stock idle higher (like with a tactrix cable and EcuFlash), it's a non issue and will idle fine.

 

When you say the S2's what size do you mean from GSC? The GSC 264/272/280 in/ex?

I am assumimg the 280's:
http://www.stikiller.com/product.php...cat=299&page=1


~Z

 

The S2's are a newer version of the 280's. They should be available shortly if they're not already. I'm running the older version called the "280's", and I'm completely happy with them on a 50 trim. The S2's should have better mid range than the older version 280's that GSC sold. Greg from GSC can speak better to this point though.

 

Ted,

I trust your opion as you seem to be the guru of cams. I have been reading some posts and you seem to know a good bit about all the differant cams on the market.

What do you feel will be my best bet with the setup I have (in my signature)?

I have to get out of these HKS 264's they are just way too small!

Would the GSC 280's be too big or would the GSC 272's be better suited for my needs?

What is the difference between the GSC 280's vs. the HKS 280's and the GSC 272's vs. the HKS 272's?

Any help is greatly appreciated,
~Z

 

It's difficult for me to comment in great detail because I don't have the specs for the latest revision of the GSC cams. At this point in time, I'd suggest contacting GSC and inquiring about which of their grinds provides the approximate equivalent effective duration as an HKS 272 set.

 

I used hks 280's for over a year bring it up to 8200 rpm without any problems.

 

 

 

Let me ask you the same questions i think i ask 20 times a day.

what would you say is your effective rpm range is? Im thinking 3700-7300rpms
what boost levels do you run?
what is your compression?
what kind of power is the car making?
Why not put new springs and retainers?
How is the spool of the car with the HKS 264s and where is it at?


FYI We are launching the S-Series cams here in the next few weeks for the evo 8. They have not been added to any of the websites as of yet. (we dont want people buying something they can't have for 2weeks).

Ted i think im going to have to email you some cam cards, you'd deffinatly make my life easier

 

Greg,

Your are correct on my RPM range, with the 2.3L my boost hits 25psi at 4,000 and starts coming on hard around 3700.

I run 25psi on 94 pump. Going to run more on race gas(30-35) and possibly look into alky to run more on my daily tune.

Stock compression (I am using the mitsu 2.4L crank with stock head gasket, I can't remember back when I was building the block but I think the compression is the same since I did not shave anything off the block or head).

Right now the car is making around 400whp-425whp and 380-399 ft/lbs. I haven't dynoed it, just road tuning, those numbers are based on my 1/4 mile times and datalog lab results.

If this helps it will show when boost comes on:



As far a spring / retainers, it would be nice to do but I am looking at selling my HKS 264's and using the money from those to buy the cams I need. I spent all my money building up the car and don't have any left. I am looking for something to get me by until I save up and just totally redo the head / top half of the motor (currently bone stock).

Spool is suprisingly not bad. Like I said above full boost hits at 4000 RPM.

Your help is greatly appreciated, I believe I have a killer combo here and maximizing it with the parts I have now is what I am trying to do. I want to be able to say I have a built motor / 35r turbo / stock head, intake mani, MAF....you get the picture.

~Z

 

I'm also interested in how far you can go with the stock valvetrain + bigger cams.

 

We can really do something for you.

I have 2 suggestions..

we made a set of chro-molly retainers to work with an upgraded spring. Cost on that kit is 229 so might swing you into investing in them. the retainers are only a couple of grams heaver than Ti and the longevity is equal to stock. Might be something to think about.. oh yeah and they can be used with a deal spring as well so upgrading isnt a problem.

I don’t have a problem with you running the S2 cams on the stock retainers and springs at that RPM, but i suggest upgrading. That being said the S2 cams are a 274 201@1mm and 11.1 lift peak, 270 Exhaust 200@1mm with 10.95mm peak. centers are 107/113 but might suggest 105 111 for you. $499 and if you did the combo with the springs and retainers it would be $699

The S1 cams will be a HUGE gain over what you have now and you can run them with ease on the stock valve train to 7800. but with the plan for the built head down the road i would lean towards the S2. The S1 cams are Intake 270 196@1mm and 10.8mm peak exhaust is a 268 195@1mm and 10.5 peak. Center lines are 106/112 $499

Which ever you decide on your going to see at least 30-40whp increase in power from where you’re at if not more. The HKS 264 combo leaves a TON of power on the table

 

As do I. Often neglected is the fact that it costs far less to install upgraded springs than it does to deal with the damage that results from failed factory valvetrain components. Additionally, the upgraded springs allows the lifters to track the valvetrain more accurately with bigger cams, which results in more power.


I recommend the S2 set for this application. As for the LC settings, 107/113 (straight up) is already fairly advanced, so I might try this first.