Ok, I have this customer that just got the skunk2 stage II cams from me. He also bought the valve springs and retainers. So now he wants to go to stage I cams. He claims that his friend has the same setup and dynoed his car. The dyno showed a loss of power until high RPM. Do you see any reason this might happen? A loss of performance Please give me your opinion on this matter.

Thanks
jason

 

some cams produce better midrange power while more extreme cams produce power in the high end. the reason has to do with the size of the cam lobes and i know with jun stage 3 cams vs the toda stage 3 cams vs the integra type r cams the toda and jun outperformed the itr cams in the top end but the itr cams made the most mid range power. this is because a more extreme lobe in the mid range will not necessarily make more power. everything is a compromise and the motor will bog in the mid range with an air/fuel mixture that is too rich.

most cams that are stage 2 and stage 3 are designed specifically for race applications where the motor spends all of its time in the higher rpm's. this makes a cam less streetable but more impressive on a dyno sheet and at the track.

just remember, there are always compromises when tuning an engine.

another way to make this point more clear is the alteration of vtec engagement points. if someone you know has a vtec controller and lowers the point of vtec they won't necessarily feel an increase in power, but rather a feel of bogging and sluggishness. this is basically the same thing your customer is talking about with the stage 2 cams and why the stage one makes better mid range power.

overall, i'd suggest selling him the integra type r or civic type r intake cams. they make the best mid range power of any cam that i've seen and this is because honda knows what they're doing. no, they're cams aren't as impressive on the top end but they're much better for daily driving.

 

john, this of course is true and you have much more experience than me. however, the design of the cam dictates the type of performance and even the best tuning cannot change how the camshaft is designed.

 

if his exhaust manifold or intake manifold were too restrictive wouldn't the dyno test show an overall lack in power...especially in higher rpm's. by going with what jason posted...his customer's friend did see an increase in performance...but in the high rpm's...which to me seems like a really aggressive cam that isn't allowing the engine to have an advantage until 7000rpm.

i would guess that with a setup like this...the car would feel like it was bogging down until the engine started turning at 7k.

with my car as it is...no cat...n1...i can definitely feel a lack of torque at 1000rpm to around 3000rpm and i'm convinced its because the entire exhaust is freeflowing and provides less backpressure when compared to a more stock setup...which is what i was running previously and is what i'm comparing it to. now, when i high vtec the engine definitely rev's faster and allows my engine to climb into its powerband much faster.

again, this is the sacrifice that i've made...and the sacrifices everyone else has to make when driving a torqueless honda. in my opinion really aggressive cams just make the lack of torque even more noticeable.

i would just stick with oem honda if the car will be driven daily. mid range power is so much faster on the street.

 

also...most stage 2, 3 cams are designed for engines that are built to spin at 10 and 11k.

thus, any stage 2+ camshaft in a motor that has a stock rev limit is a waste of time because there is a huge sacrifice in low end power with the bigger lobes.

 

here is a b16 dyno let's see if chet can guess what cams they are.

 

here's something else to digest...and yes getting 174 horsepower out of a b16 is definitely impressive. what exactly was done to the motor?

this is a dyno test that was performed by import builders. i know, some of you might be skeptical of their results..etc..etc...but i've read many of their reviews and i'm pretty sure their honest. plus, i've talked with jeff a few times and he seemed like a good guy.

here is a good example of how different cams produce power in different area's of the power curve.



and here is what jeff said upon his review. see if everyone else agrees with these results and understands what i'm trying to say.

yes, the type r cams came in third, and overall produced less horsepower...however honda could easily design a cam that would perform as well or better than the toda's and jun's in the high end...as their technology and experience far outweighs every aftermarket company...but they aren't interested in just getting the highest numbers...but rather producing a camshaft and a motor that has a nice idle and good mid range torque.

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