272 cam idle problem again
 

this bad idle problem has been discussed over and over again, but many people still dont understand
272 (high lift cams) will idle badly when the car is not tuned properly.
you wont gain 60 hp when you install those cams and your car probably wont idle too well.

shawn glass quote:
"Cams - I was able to finally track down my idle problems, although RMR says it isn't the cause of my car dying at idle. I had my 272/272 cams taken out, and voila, the car idles like stock again, no idle fluctuations, no sputtering and dying. Cost me $450 to have them and the cam gears taken out by the dealership. I called RMR, their response? Well it wasn't the cams causing the idle. Other people have them and their car(s) idle fine. WTF? If a car dies and doesn't idle before taking a part out, then once it's taken out and the factory part put in and the car idles fine, doesn't common sense tell you that the cams were causing the idle prob??? I asked them to refund me the cost of the labor to pull the cams out, they said no, the cams idle fine. Lot of common sense there huh? "

Shawn, rmr is my competition and I see they pissed you off real good, but..
272 cams will have idle issues, you have to fuel tune your car really good to get rid of the idle problem. Those cams are designed with hks springs (even though some people dont think so) and will make a difference on 400hp + car. Even JUN uses 264 on their 500hp+ cars . BIgger is not always better.
rmr is not perfect but in this case they are not the person to blame for the idle problem
just my .02 cents :)

I just wanna be fair to people who ordered JUN cams from me.

know what youre doing, get a mechanic who knows what he's doing.

rmr cant be blamed for 272's bad idle with everything else :dunno:
if he spend that much money, they should have given him a refund.

I think with any after market item you run the risk of not being the same as stock... you need to know what it is your buying.... its your fault man.... I got the ssbov, before the VTA discussions here.... I made the mistake...instaed of arguing I fixed it with a recirc kit.... maybe you can get RMR to exhange them for the 264 or something...

REASEARCH before you buy things

-Shahul

i dont think shawn and rmr are even talking now :D
rmr could definatelly exchange the cams, I would
paying for installation and removing the cams, I dont know,

No.....these guys build rally cars, they should know what works and what doesn't they claim to be experts..it seems they put the guy that normally makes the coffee and sweeps the floor in charge of this project..with all of those mods he purchased they should not have released the car back to shawn glass without making sure it ran pefectly after a good shakedown...not being able to idle.....thats bad....not being able to select gears..thats bad....if it happened on thier rally cars they would never enter an event ....no excuse IMO

Caveat emptor.

they built relly cars???
holy ****, I didnt know, I guess they made enough money, so now they can lose $15000 customer :D

272's have a weak vaccum, so it ishard to get them to idle, BUT you can do it with tuning, it is all about tuning, you can't just through them in and hope for the best, tuning is key.

I would go for the 264-272 combo, its the best street wise....

What do you guys mean by tuning? What would you tune to improve the idle with 272s?

I just ordered 264 intake / 272 exhaust from Boost Solutions, I'll let you know if that combo runs smoother than straight 272/272's (which my friend has in his 1g).

Somebody said 272's have weak vacuum. What do you mean by that? Like, less than the 15 to 20" of vacuum at idle? If that's the case, how much vacuum woukd 272's give at idle, and what's the downside of having less than stock?

Well the Evo only has about 16 inHg to start with, so your are probably going to drop down to like 13 or even 12.
The problem is the overlap. the amount of time the int and ex valve is open at the same time bcause of the long duration of the cam. There is no real big downside to low vacuum, but it affects things like the power brakes. A vacuum reserve can be used to restore proper vacuum to the brakes.

I think the 264/272 setup should work well.

I run the full 272 setup and you're right about the vaccuum .. I pull about 11-12 .. the car will stumble when it drops to less than 10 ..

Oh .. BTW .. I run perfect idle with an occasional stumble :D :D

every car is different and unless the cams are set based on the manufacturer specs (ie 108 LCA for both the cams) and adjusted from there .. it's hard to get a baseline setting that will work nicely ..

Minimising the overlap was the reason for my success :D .. then again .. I wasn't all out for hp .. I set the cams for midrange punch.. sorry no dynos .. all the tests were based off runs against other cars and against speed at 1/4 mile .. highest speed achieved was 108mph .. at 90s temp and 100% humidity at sealevel .. :P

You can tune out the low vacuum at idle with adjustable cam gears. I had a friend with a 2nd gen Talon with 272 cams. He adjusted the cam gears to get his to idle as smooth as stock without even a hiccup. You will loose a little top end power but can have a very good idle.

Brian

That is really the only way to smooth the idle out by degreeing the cams. The slight loss is really nominal because no one drives at 6-7K anyway. Otherwise you have to play with fueling and idle speeds, etc to try and get some reasonable results at idle. You can get it to run pretty well but the cam gears really make it easy in comparison.