ask Silver surfer.... he says that 272/272 can be made to idle great with more power with cam gears.... set at -4/-1 or 1.5

-shahul

 

I saw the maps that silver surfer posted, it will help with the low-end a bit but if you compare the map between jun and hks 272, you will see that the hks one has much better low-end, I am not talking about 2-5whp i am talking like 15-20whp at certain rpms more then the juns. The juns are supposed to have higher lift resulting in better low-end/mid-range, but the graphs proves this to be wrong... I am wondering if anyone knows why. Because there has been lots of talk about higher lift being better for responce, low-end power and torque....

 

I think you missed my point - the JUN 272s have both more lift and more overlap than the the HKS 272s. The larger overlap is what is killing the low end torque. The HKS 272s comepare more closely to the JUN 264 cams, but the HKS have less aggressive lobes.

The JUN 272s are BIG cams designed to be used in a heavily modified car. Al did some testing with them and found them too aggressive for anything but a full on race car. He pulled them out of his car and moved back to the JUN 264s.

You can't just look at the lift and duration and know how a cam will perform. The shape of the cams lobes, called the profile, is very important and will affect both performance and driveability. Also, lift and duration numbers are not measured the same way from vendor to vendor, so an HKS 272 does not have exactly the same duration as a JUN 272.

 

Right then... cheers mate.. i actually missed your post...heh heh ..I was hoping someone could clear that up for me... how do you calculate cam over lap? This might be a silly question but id really like to know...

 

Looking @ the results from http://www.automotosports.com/cam_test.asp it would appear that the 264/272 Combo is going to be the best. You lose 1HP but you gain 10ft/lbs of tq. over the 272/272.

 

Hi Airtreking, I'm not sure there is even good hard data available. Between lift, duration, overlap and lobe profiles you have an amazing number ways things can be different, but be given similiar labels. Another thing to remember is that overlap can be tunned out to a small degree by changing the mechanical valve timing of the engine with a set of cam gears.

I ended up researching the different cams I was interested in and finding out if they were being used successfully in cars that matched where I am planning to go with mine. Within that info, I started trying to draw some comparisons from other peoples experiences. Not exactly scientific, but better than "those look cool!".

One other thing to consider is that matching you planned configuration (within reason) is important. Different heads, exhausts, turbos, intakes, etc. will all impact how much a given set of cams will flow in your engine, and what the power band will look like. Charts like the ones posted above are useful, but not 100% accurate when moved from a DSM to an Evo - the stock Evo head is supposed to have better flow characteristics than the DSM head tested. That could mean an Evo may benefit more from the HKS 272s than the charts above show; of course without a direct comparison on an Evo, you can't be sure.

 

Oops - re-read a post above and I need to cleanup my comments about duration. It isn't that vendors measure duration differently, but different cam profiles will achive a higher lift more quickly and hold it for a longer time. This can give an "effective duration" or "duration at 1 mm" that is very different between between cams with the same duration rating.

Anyway, hope this helps.

 

Ding ding ding! We have a winnner!

I went with the 272 because I plan a turbo upgrade in the near future and saw no reason to do cams twice..... but in actuallity 264's are better for the stock turbo than 272's. Better low end power, better idle, and no difference in top end if you are sticking with the stock turbo.

Keith

 

Hmmm, If i am sticking with the stock turbo (meaning the evo 7/8 turbine) which one will be better in terms of streetability and power gained? the tomei procams 260 11.5mm lift ex/in or the HKS 264/264 setup with 10.8 in and 10.2 ex? one has more lift and the other duration, but both have good idling and claim to be very steetable....

 

I would go with a 272 intake/264 exhaust. I think that having a higher speed of exhaust flow will be better for a turbo than just more exhaust flow. U will get higher speed of exhaust flow to the turbo with a smaller exhaust duration than the intake. Since u are getting the same amount of air inside the combustion chamber due to the same sized 272 cam the result will be higher exit speed for the exhaust flow to the turbo. It is true that u will get more exhaust flow out with a larger 272 cam, but it’s not going to be as fast. The most important thing on the exhaust side in a turbo is to spool up the turbo so u don’t care about how much exhaust flow u are using and a 264 will spool up the turbo faster than 272 and u will get ur perfect mid range. On the other hand, the 272 on the intake side will give u the topend u want too. This will work on both stock turbo and upgraded turbo. By the way, I asked a physics professor and a Math professor about which would be better to spin an impeller inside a turbine, AIR SPEED or AIR FLOW rate. They said AIR SPEED with respect of the turbine size, but in the case of a 60mm turbine a 272/264 would be better than 272/272 or 264/264.

 

So anyone running this combo HKS 264in/272 ex with the stock turbo?i am very interested in of this setting for my car.

 

You want 272 intake and 264 exhaust

 

Alot of people are running that setup, do a search and your'll see alot of threads. Exspecially the past couple weeks.

 

The 272 i/264 e setup does seem to get the most love.

I wanted to get the best idle with stock cam gears, and settled on the 264i/272e setup.

I saw that some members were getting really good results with the gsc cams in this config. I went with the Buddy Club cams and with a Custom Dynoflash made 331 HP and 338 TQ uncorrected... Al was impressed considering the stock airbox with K&N panel filter...

Idle is pretty good, but not perfect. low-end, spool, mid, and top-end are all awesome. Personally I wouldn't want any more of a lope at idle, but if you get cam gears I'm sure you can make 264i or 272i idle great...

I bet there isn't that much difference between any of the combinations other than idle on the stock turbo, ceteribus paribus (all else being equal). Previous dynos have shown that the straight 264 and straight 272s make similar power on the stock turbo, so I think it will come down to your preference. I've also seen differing opinions on what "should give the best spool, best midrange, and best top-end but I think they're pretty close.

Thoughts?

FB

 

After reading this page: http://www.automotosports.com/cam_test.asp

I think that the best setup for someone who is going to run, stock turbo, stock internals. hks 264 in / 272 ex, its the best setup..

The persons that can tell the best opinion are ppl running this setup! hehe