Cams vs. Underdrive Pulley vs. Nothing

[laser92awd]

My water pump died and I am in the process of changing it and the timing belt. So while I have the side of the engine off, I was thinking about doing an upgrade at the same time. But I've heard pros and cons so I thought I'd ask for some advice. I'd really appreciate it if you'd only post if you have actually done this on your car - not just what you've heard about it:

CAMS:
I have a VPC / 16G / 550's. Since I'll have the timing belt off I could pull the cam sprockets and valve cover and put in a couple HKS cams along with the right VPC chip. But the cons I've heard is that even HKS only claims an 11 horsepower gain and it is way up high in the revs. Also that idle and vacuum suffer significantly and this car is a daily driver.

UNDERDRIVE PULLEY:
The pulleys would certainly be super easy to install and I need to buy new belts anyway, plus it would cost a lot less than cams. There are several options here. I like the looks of the underdrive pulley sets from Unorthodox and Mach V. The problem is that with the crank pulley you loose your harmonic dampener. Some people say this is horrible, others claim no ill effects. My engine is bone stock - not balanced. Buschur Racing sells an expensive underdrive pulley WITH a harmonic dampener, but I believe most of the gain from an aftermarket pulley would be because of lighter weight - not so much the underdriving of the accessories. And with a dampener built in I imagine it isn't that much lighter than stock. And nobody seems to have dynoed any of these that I can find. Same gains as the cams? More? Less?

NOTHING:
I recently went through the big pain of "bolting on" an extrude honed intake manifold. I can't state any track times on this yet, but the car doesn't feel any more responsive. My brother just put a super lightweight flywheel in his VR4, and again I couldn't tell any significant difference. Maybe I should save my money toward my next clutch?

Thanks for the advice!

 

[InferiorWang]

ive heard that if you get 264/264 your idle wont suffer bad. Some people have gone more aggressive and say it isnt bad but it is all opinion. I think you would see the largest gain from cams.

 

[laser92awd]

Ok, that brings up a question. Does the VPC prom dictate which HKS cams you can use? If so which ones?

Jonathan

 

[L2RTSiAWD]

I can say I have full underdrive pulleys and HKS 264/272 cams.

I felt a difference after the install of each products

HKS cams-my car idles fine after some messing with the AFC

 

[laser92awd]

Does the 264/272 combo sound like you have cams at idle? At what point in the powerband did you feel like you could feel an improvement with the cams? When people talk about low vacuum - is that just an idle issue? I have a VPC and GCC and a Pocketlogger so I can do quite a bit of fine tuning.

Much of the negative feeling I've been getting about going with the cams comes from 2 things:

1: It will cost over $700 for the cams, vpc prom, valve cover gasket, and misc expenses. Is ~10 horsepower way up high in the revs worth the expense?

2: The "1000 already answered questions" page has this to say about cams:

"...those who have installed new cams have often reported negative side effects, such as low vacuum and poor idle, which appear to be endemic to cam changes. Much more rare are first-hand reports of verified performance gains, making DSM cams a doubtful upgrade when compared to other modifications" and "To add to the confusion, Leon Reitman actually removed upgrade cams from his car after finding they provided no performance gain, despite HKS' claim of 11hp. David Buschur stated here that cams would not be a worthwhile upgrade for 99% of drivers, as the cam change only makes more power in the higher RPM ranges. It has also been reported by Kyle Zingg in the Dec. 21, 1998 Digest that a prominent vendor recommends against changing the cams, as the stock cams provide the most power."

Jonathan

P.S. I've pretty much ruled out an undampened crank pulley. I'm just not willing to take the risk. I would still consider a dampened lightweight pulley if only I could find somebody with some real evidence that it is worth it. I guess I'm at that point with my car that every tenth is going to really cost me. So maybe should I go with the "nothing" option and start thinking about a larger turbo? Does anybody know if you can get a VPC prom to run a turbo larger than a 16G?

 

[L2RTSiAWD]

I feel an increase of power at 4k and up.

 

[doug]

Originally posted by laser92awd
I've pretty much ruled out an undampened crank pulley. I'm just not willing to take the risk.

FWIW, there's also a risk with leaving the stock pulley in there. I've read far more accounts of the stock pulley separating and causing damage than damage from one-piece underdrive pulleys. To me, I'll chance the risk of "harmonic vibration" causing damage vs. the chance of a stock crank pulley flying apart causing damage. I'm not saying there's NO evidence of this undampened pulley killing an engine, just that I haven't read about or seen first-hand anybody that has actually had that happen to them. If someone can relay their experience with that, I'd really like to hear about it.

 

[laser92awd]

Hey that's a good point. My pulley actually did seperate about 2 years ago but fortunately I had no damage at all. But there really isn't anything that will keep that from happening again with the stock replacement I've got on now and maybe this time it could take the timing belt with it.

I guess there are a lot of ways the engine could grenade itself.

Now I'm starting to think about the pulley set again!!! grrrr...

 

[L2RTSiAWD]

My pulley set was great. I noitced and inprovement is spool-up time.

However I also noticed that my interior lights do dim a bit. Do not get pulleys if you have a high-power stereo or ar drawing alot of eltrical power.

 

[laser92awd]

I have a small amp and CD changer as well as a self powered bazooka tube. None of it is really high power. But it is more than stock. Why don't they make a pulley that is lighter but still the same size so that you can use all your accessories the same way but still get the weight savings?

Jonathan

 

[doug]

My pulley isn't the Unorthodox one and it doesn't "underdrive" quite as much as those do. It's made by Pro1-- I had never heard of them before but my brother-in-law who runs a shop got it for me and said they weren't bad. It's pretty lightweight, though. Quite a noticeable difference when you're holding it in one hand and the stocker in the other...