So the only reason you used this cam is to make your car sound insane? after all the engineering you seem to have put in you say you only picked a cam cos it sounds good.. seems strange. I would much rather have a car that makes 320kw on a mild cam then 360 with an insane cam and extreme overboosting issues. Just my extra 5c. Seems to be a lot of shrapnel around...

no, i did not pick this cam to make my car sound insane, this cam was a very careful, well designed custom grind from phil at surecam, he is the cam guru, not me... the fact that my car sounds nasty with that cam was a reason to do everything in my power to allow me to control the beast.

people say, why not just use a smaller cam?? cos' that would be selling my self short, you say ive put a lot of effort into it, and i have, so thats why i want to use all the best ingredients available to me, there was no way i was going to settle for a lesser cam, based ONLY on convience... thats all it really came down to, the hassles of working out my setup, now its sorted i couldnt be happier with it

EXCEPT, 350rwkw would make me even happier, LOL

So you didn't. Hang on
.

So you got a hot shot cam, discovered that it sounds and feels like some abbo pinched a couple of spark plug leads when your car idles and you refuse to change it for that very reason, yet you won't spin the engine hard enough to make full use of that cam for fear of breaking something. Dude you sound like a rich kid with a fat wallet who should belong behind the wheel of a pre built VL turbo.

If I wasn't a financially struggling uni student I'd show you exactly how to build a monster I6. With or without custom parts.

Have you read this f**k thread?
The guy has made not one, but two different exhaust manifolds, he made his own intake plenum, done the entire buildup himself, and you are claiming 'rich kid with a fat wallet'?
Get off it.

ebs_4l, your car looks, and by the video goes, very nice, I think you've done some great work.

note, was A reason, not the only reason...


maybe could have worded that differently, can you grasp a two part answer, part a) the cam was designed for, and is suited to my setup, and is meant to be ideal for my application... b) i like the way it sounds, therefore, im even more inclined to try use it


geez mate, put ya glasses on and read the second part of the last post, it says, in summary, that i got a prime part, it caused some issues in another area, which with some development, allowed me to use my prime part.. in your eyes, youd say, bugger this really good bit, ill downgrade to save myself some hassles??? thats the way i read it


please, im keen to know where the full potential of my cam lies????? LOL, what are you meaning by SPIN the engine hard enough??? are you refering directly to not revving the engine to high enough rpm?? as a uni student you would be smart enough to understand the increase in conrod loading that comes with increased rpm. RPM is the most common killer of rods, not cylinder pressure


3 things here, im not rich, i was an apprentice mechanic at the start of this project, up until 6months ago, i hate commodores, and none of my setup was pre-built.... all my own blood, sweat, tears


i look forward to the day when you can show this off, maybe then there may be some credibility behind your comments.... until such time, you are arguing about something which you have no real experience doing.

oh, and since you know so much about constructing a monster, i look forward to seeing how you go about fabricating your own manifolds etc, and how far you will SPIN your own hard work

Last edited by ebs_4l on Wed Aug 09, 2006 9:37 pm, edited 2 times in total.

LOL, yea, that sums it up.. spot on

im happy you appreciate the effort steady, i can count on one hand all the other turbo systems on here that have been built to the same degree, AND, out of those systems, HOW MANY HAVE BEEN BUILT AT HOME???? not by a workshop

i couldnt have said that better myself, but i didnt want to get too offensive

Do you know what happens when you put an overly large cam in a turbo engine? A large portion of the air that should be inside the cylinder when the spark plugs fire is actually in the exhaust maifold. In a sense you get massive reading on your boost guage but that is just the air pressure between the TB and the Inlet valve. Your effective pressure (cylinder pressure) is much lower then an engine with a smaller cam. And you have to spin the engine much harder to get any effective pressure from the turbo. Most people will only realise this when they stop and think about it.

I build all mine at home too, well apart from the manifold that I bought from snort performance that is.

ebs_4l about your comment "if they had a decent flowing merge collector and if that was fitted to a decent flowing combination, with a decent turbo, they would have absolutely no hope in hell of that wastegate outlet working... trust me "
Without using their manifolds, and by your own omissions it was your cam that was causing your over boosting issues, it was really an unfounded comment. Bad mouthing someone else’s work is fairly low in my opinion..
I’ve used their manifolds, and know of quite a few other people that have also, with no over boosting issues at all, some of them with GT3540 with smaller exhaust AR then yours.
Saying all that, I think you’ve done a great job on all aspects of your car, and you should be very proud of what you have achieved, which is, a really good result.
It will be interesting to see how long your manual will last, my guess is it’s the weakest link in the whole combination now.
Good luck with the new tune.

About your cam choice. With my very limited understanding, I’m guessing you are running a large overlap, which you have done to decrease spool up time?? So does that means that a proportion of your boost is passing straight through your engine and out the exhaust to the turbo???
Would a side effect of this be, that raw fuel will also be passing straight through the engine into the exhaust as well? Also would that cause the turbo to be effectively spinning a lot faster then it should to produce the same amount of boost? The only reason I ask is, that I’ve heard of turbo’s been damaged by over spinning. Also I’ve been told that turbo have an efficiency range, which when operating out of that range causes high air temperatures among other things.

Just wondering as I’m looking at getting a cam for my setup shortly, and have been told by everyone that I should be looking at having the smallest overlap possible..

In an ideal (read dream) world a turbo cam would have maximum lift, maximum duration and zero overlap.

woulent that be nice. but like ebs_4l's cam, large duration comes along with large overlap.

to much duration wouldent be ideal not only because of overlap, but it would have a narrow power band in the low reving 4l

ok, ok, ok.... i have one BIG question in particular for you xcabbi...

what sort of exhaust manifold vs inlet manifold pressure difference exists in a average turbo charger system?????? remembering, this differs GREATLY to a supercharger system, where what you are describing is exactly true

im guessing you think there is LESS pressure in the exhaust and so my boost is blowing straight through??? thats what you are trying to tell me

oh, make that two questions, how much overlap do you consider excessive??? and how much overlap do you think i have? what sort of overlap are you basing your comments on?? and with this answer, let me know in .050" and advertised....

Last edited by ebs_4l on Thu Aug 10, 2006 6:41 pm, edited 2 times in total.

perhaps i should ring phil back and ask him if he understands my car is turbo, and if he knows how turbo cams differ from n/a cams, cos by the look of the design sheet, he obviously didnt think about it too much....

Speaking about reground cams and i won't mention any names, i've had two experiences with them. One good and one not so. First was a standard EB with huge Km's on it, wacked a regrind cam in it, dialled it in and without a tune it manages a 14.9 quarter. I'm pretty sure the car has 3.45 diff gears and a T5 but you'd have to be happy with that.

The other one though couldn't be dialled in to the 60thou spec as the pistons were going to smash the valves. Ended up having to leave it at 42thou. Cam had 272 duration and enough lift to bind the springs.

Although that cam sheet above isn't all there i can tell that it's pretty extreme for turbo application and would be suited to circuit racing more than anything. Reasons being the fuel and air blowing through the cylinder during overlap will act to cool down the valves and pistions ect. Probably wouldn't be a real good cam for fuel economy and general street use (towing a boat) but i'm guessing you don't chuck a turbo on your car if your interests are with fuel economy.

IMHO a good turbo/street cam is usually not a great deal different from the original. All you really need is a little more lift and slightly more duration. Advancing the cam using a vernier if you can works pretty well. A cam with huge overlap is what's used in those 2 litre 4 bangers at the jamboree. It's the only way to get a T66 spinning on an engine of that size.

i'm still trying to make a cam choice.. atm i have an ED XR6 cam.. but wondering if i should go a little bigger... getting head work done atm... but stage 1 i want to be running 300hp atw.. i do want to go bigger.. which hopefully will just be a case of increasing boost.. until the bottom end blows up.. then a rebuild with stronger internals.. and even more boost