The discussion is interesting. There's a theoretical and a practical way to go.
I'm impressed by the passion and knowledge by some members, you know who you are
The final result is the proof, even if there's rarely any identical builds to compare, it's what most people like to see. So here's my dyno on low octane pump gas, stock cams and heads... and kinetic ssv (not on new build though)

 

What are you talking about? What specifically did I copy and paste. Please enlightent us...

And where did you guys in Arizona go to school? You obviously have a serious issue with reading and comprehension, because nothing you to try to describe after the fact really matches very accurately with what is originally written. Did you even make it past high school???

 

Nice Job!!!

 

Why does the dyno stop short of the stock redline?

 

You really need to working on reading comprehension. Where exactly did Terry say that JWT cams are the best? He simply said that JWT has extensive spec sheets instead of basic cam specs from others.

 

That's on Greddy 18Gs right? Not bad for pump gas and stock cams.

 

Really good stuff Terry - thanks. I didn't think about the spring being subjected to non-sinusoidal movement (from the cam) and the impact that might have in generating harmonics in the spring. Interesting though it may be I suppose in the end we have to trust the designers and build on that with the empirical data points from the folks that post onto the 'net. Given that, it makes sense when you have little real world data to match up cams/springs where possible as recommended by the manufacturer. I stand corrected.

 

i know hat you are saying, but point is...and its IMO(if you agree with it or not), but i support/suggest/push for products that i have seen them perform(again >1000hps cars), not just because of what i've read on a message board or a PDF. I would think DIY guys would specifically go for(products) what performance is in fact proven on high whp builds(since thats what your car is)

 

Jorge, prefering real world data over theory is a reasonable approach, but sometimes there's a lot to be gained by considering both. And high whp builds are not the be-all end-all for product validation (imo). This guy, go-fast, whoever he may be, made a really nice post (see below) and conveys a philosophy in building that really strikes home for me. What's the point of building a "dyno queen" for a street car? Just because you can hit 1000+ whp, while a great accomplishment, doesn't necessarily mean you haven't sacrificed something, perhaps a great many things, in the process. It doesn't mean that start up issues, or stalling issues, or the weird vibration you get at 3k rpms can/should be ignored because that car doesn't spend any time at that particular point in the rev range. For most of us, it's the whole package, as go-fast says, the "most smiles per mile" that we are ultimately shooting for. Not a specific whp #, be it above or below 1000 whp. So with that in mind, even if a JWT cam has never seen a 1000+ whp build, so long as it does what it was designed to do (i.e. a nice broad torque curve in the range desired with no driveability or reliability issues), I would still recommend it. Hope that makes sense.

 

I'm not looking to make huge power at all. I want the most reliable, streetable setup possible. I love that my car is pretty much as reliable as it was stock while having a bit over 500rwhp. I also love that I can sit at a light with my A/C on and not even feel the engine idling. If I do go with upgraded cams this winter (will depend on how my car does at the track this fall with my Cosworth IM and meth injection), I will be looking for cams that will give me a nice thick powerband, not peak HP numbers. I honestly have been trying to avoid upgrading the cams if at all possible.

 

If you decide to upgrade your cams, and you are concerned about idle, you need to be careful about how much valve overlap at top dead center (TDC) that you go with. In general, the greater the valve overlap at TDC, the rougher it will idle, but the more top end power you will gain. You will usually lose a bit of mid rpm power as you increase the overlap, however.

If you bump your idle rpms, that usually helps smooth out the idle. With the C2s (26 deg. overlap), they idled a little rough at first. Then I bumped my idle rpm to 850, and they idled fine. If you don't want to change your idle, you should go with something having less overlap.

The valve overlap usually increases as the duration increases, but is not always proportional. For example, some manufacturers use the same lobe separation angle accross a number of cams, whereas other manufacturers increase the cam lobe separation angle as the duration is increased. This increases the overlap at bottom dead center (BDC), but varyiations in BDC overlap have very little impact with regard to performance in comparison to variations in TDC overlap. Note that I'm using the term overlap rather loosely with regard to BDC because there is not valve overlap at BDC. I am using it to mean the amount the exhaust valve opens before BDC and the amount the intake valve closes after BDC.

 

Brian, JWt S1's idle like stock and had tons of midrange. Id recommend that cam to anybodywho wants more power with stock like characteristics with nasty midrange and better top end.

The BC's took a while to get used to, as they felt dead as ***** midrange with a top end that initially felt weaker than the JWT's....

 

Increasing fuel at idle can help with larger cams, too.

 

+1

We did that too.

 

Raj, I hear and appreciate what you are saying.

It's all good until theory is asserted as fact over real world data and experiences. In this thread, theory and JWT marketing fluff were used to propagate a fallacy about JWT springs & cams. go-fast called it out and attempted to correct the misinformation about JWT springs and the supposed harm in using different brands of springs/cams in combination (given the available brands/choices on the market for the VQ). Real world experience within the VQ community supports what go-fast stated. The results of tons of builds posted in this forum do not support Terry's assertions. It is misleading to the community and folks such as Brian (who already have JWT springs with stock cams and are looking to upgrade) to suggest that they should only get JWT cams in combo with JWT springs and that anything else is potentially harmful with those springs. I think it is a disservice to the community to let such things be propagated as fact and go unchallenged when there is a lack of real world experience within the community to support it.

Case in point that does not support Terry's argument (which conveniently got glossed over)... Ferrea does not make cams for the VQ. Yet their valve springs have been combined with almost every brand of cam available for the VQ. We've seen plenty of builds over the years where Ferrea springs were combined with JWT, GTM, Nismo, Tomei, BC cams, etc. with positive results and no indications of harmonic imbalance or problems associated with the spring/cam combo. This includes my longblock with Ferrea valvetrain and Nismo R cams that performed well in the previous owner's Greddy TT Z up to 700whp. The motor has since been torn down and inspected without showing any signs of problems or issues related to the valvetrain or cam choice.

I'm not proposing that guys should half hazardly mix brands of springs/cams for the hell of it. If somebody is upgrading their springs and cams at the same time (as most do), it's logical and typical to stick with the same brand when possible. But for those who upgraded just springs or just cams prior, I think it is BS to tell them that only spring A will function safely or properly with cam A and vice versa.

I agree with you Raj that 1,000+whp builds aren't for everyone, but I disagree with those who say you cannot make a 1,000whp car streetable. Keep in mind that guys with 1,000+whp street cars (ie. Supra guys) typically run lower power settings on the street and some actually do care about drivability when they aren't running max power. You don't necessarily need huge cams to achieve 4-digit power levels either. The Sound Performance 1,200+whp shop Z, Intense wide body G, and Jorge's 1,000whp build have BC stage 2 cams; not stage 3. The BC stage 2 cam is a relatively mild cam (based on advertised specs) that thus far has exhibited excellent midrange and top end powerband beyond stock redline while still retaining decent idle quality and good drivability for street applications. Even though the BC stage 3 is more hardcore and isn't advertised as a street cam by BC, folks like Alberto have had good success with it in street applications and were still able to maintain a useful powerband. IMO, the fact that some of the premier shops in the community are using BC cams for their builds is noteworthy and it shouldn't be casually dismissed as something just for dyno queens.

 

+1

I have heard similar things about the JWT S1 cams. I think Nismo R cams, Tomei 256 or 264, and BC stage 2 cams are also worth considering.

 

Very good info, thanks again Terry.

 

Sweet, if I have to go the cam route over the winter (which hopefully I don't), that's exactly what I want.

 

Thanks Rude, but just to clarify, I didn't mean to imply that you cannot make a 1000 whp car streetable, only that the whp # (1000 or otherwise) has nothing to do with it. You can have a 300 whp car that isn't streetable. Apologies if it came across otherwise.

Terry was merely disclosing that there is an engineering basis for not haphazardly mixing springs/cams because some forethought does go into making them work well together (by the manufacturer). Nothing more or less. He didn't suggest that a certain combination would fail. A complex analysis would be required to make such a claim. Based on real world data, I think some combos work well. It's all good.

 

thanx! hoping to get it better this time though

QUOTE=Alberto;7764868]Why does the dyno stop short of the stock redline?[/QUOTE]
Curve is starting to point down

Yupp 18G's Problem is that EGT gets to high on prolonged runs as on track or when maxing out speed. Better cams and porting and doing the valve seats shall hopefully cure that and my sense of lack of power