I really want to know how to do this because I am thinking about buying cams I want to get the Stage 2's 264/264, but I havn't the slightest idea on how to tune them. Does anyone know? Also can the Mk3 get smogged with these cams?
How do you tune the Brian crower cams for the Mk3?
- Thread starter SUPRASTEVE
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Just degree them as per the "cam card" that comes with them.
Then on a dyno you may want to make small adjustments to the cam timing (via adjustable cam gears) to make "different" power (i.e peak vs. avg.) This of course will be dependant upon a lot of other variables...turbo, head flow, style of intake manifold, compression, etc., etc.
Then on a dyno you may want to make small adjustments to the cam timing (via adjustable cam gears) to make "different" power (i.e peak vs. avg.) This of course will be dependant upon a lot of other variables...turbo, head flow, style of intake manifold, compression, etc., etc.
Slow66;990820 said:
yes
even though it is a dieing art. Degreeing a cam is still necessary to account for manufacturing tolerances and changes in head thickness from milling etc.
If somone has these cams on a mkIII turbo could you post your cam settings?
I have been playing around with my BC264s and I have ended up with
+4E and -4I
That is quit a lot off from what is recommended by BC. I have not had them tuned on a dyno but just from idle quality and "feel" of the car.
My main approach was to adjust idle quality since I have been told that a turbo engine should be idling smoothly. So I started taking out overlap until idle was smooth. That meant keeping the exhaust around +4E to +3E. Retarding the exhaust to less than +3 would severely affect idle quality.
Retarding the intake more than 4 seemed to make low rpm power fall off but seemed to increase high end power a bit.
But all this is without a dyno and therefore quite vague.
(I hope I haven't misunderstood + and -) (+ clockwise and - counter clockwise = advance & retard)
I have been playing around with my BC264s and I have ended up with
+4E and -4I
That is quit a lot off from what is recommended by BC. I have not had them tuned on a dyno but just from idle quality and "feel" of the car.
My main approach was to adjust idle quality since I have been told that a turbo engine should be idling smoothly. So I started taking out overlap until idle was smooth. That meant keeping the exhaust around +4E to +3E. Retarding the exhaust to less than +3 would severely affect idle quality.
Retarding the intake more than 4 seemed to make low rpm power fall off but seemed to increase high end power a bit.
But all this is without a dyno and therefore quite vague.
(I hope I haven't misunderstood + and -) (+ clockwise and - counter clockwise = advance & retard)
Kristian: One thing to keep in mind and be aware of is the less overlap you have the higher your dynamic compression will be at the same boost level right up to the point where detonation/mechanical damage occurs.
ok thanks.
Do you think I have taken out too much overlap? I'm running 2mm MHG and stock turbo.
I would really like to hear from someone who has actually had these cams dialed in on a dyno. It might make it a bit easier for me to find a resonable setting.
Do you think I have taken out too much overlap? I'm running 2mm MHG and stock turbo.
I would really like to hear from someone who has actually had these cams dialed in on a dyno. It might make it a bit easier for me to find a resonable setting.
Ok degreed they should have 114 lobe centres......
Add your 8 degrees and your really closing the leak and bumping cylinder pressures.
As a matter of interest can you run a comp test with a fully charged battery and the throttle held open please?
"safe" for me is pulling 4 degrees out of the overlap and without testing and running the motor on the Dyno using electric ears I wouldn't chance 8.
Add your 8 degrees and your really closing the leak and bumping cylinder pressures.
As a matter of interest can you run a comp test with a fully charged battery and the throttle held open please?
"safe" for me is pulling 4 degrees out of the overlap and without testing and running the motor on the Dyno using electric ears I wouldn't chance 8.
Thanks. I'll bump it back to +3E and -1I then.
The compression test is actually quite low at +4E & -4I but I didn't test with a good battery nor with the throttle open.
I have posted this before:
I'll see if I can get one done tomorrow - not sure though.
The compression test is actually quite low at +4E & -4I but I didn't test with a good battery nor with the throttle open.
I have posted this before:
I'll see if I can get one done tomorrow - not sure though.
Ok, thanks. I was told that it was in the low range.
I was actually worried about the "low" compression since the motor is brand new.
Actually the compression is a bit higher now since I had the valves adjusted since that compression test was performed. Three of the valves were sticking slightly on cylinder 1 & 2.
You have been really helpful, thanks a lot.
I was actually worried about the "low" compression since the motor is brand new.
Actually the compression is a bit higher now since I had the valves adjusted since that compression test was performed. Three of the valves were sticking slightly on cylinder 1 & 2.
You have been really helpful, thanks a lot.
Very welcome Kristian!
As with most "adjustable" things more isn't always better and if you don't understand what the adjustment is doing in relation to your particular setup you can "adjust" to engine failure.
It's great that the guys are starting to learn about all this but please proceed with caution.
As with most "adjustable" things more isn't always better and if you don't understand what the adjustment is doing in relation to your particular setup you can "adjust" to engine failure.
It's great that the guys are starting to learn about all this but please proceed with caution.
I have 9mm cams running at +5*Ex and -2*In and I'm not pulling enough vacuum at idle. Idle rpm is 700. With the cams at 0 (no adjustments) the engine will not pull any vacuum. The cam gears are aligned correctly with the crank.
How can I increase vacuum at idle without adjusting the cams even more. I can only think of raising idle speed but I am unsure of how to do that.
How can I increase vacuum at idle without adjusting the cams even more. I can only think of raising idle speed but I am unsure of how to do that.
bowsercake;991588 said:
as IJ and I stated. Did you degree the cams to see what it is actually doing?
I am quite baffled out how anyone can put in such a critical part and not double check the measurements that are supposedly there. Astonishing!
figgie;991683 said:
I agree.
"Degreed" as in using a degree wheel on the crank, and a dial indicator on the bucket to measure valve lift. Not just "degreed" as in lining them up at TDC...
Well, I don't see how it is possible to degree my cams without knowing what they should be degreed to. Is there some sort of formula or general knowledge to follow to degree cams based on their specs? I don't have a cam-card or any other reference to follow so I just reinstalled them they way they came out.
At what crank angle (generally) should it open to .050" at?
At what crank angle (generally) should it open to .050" at?
bowsercake;991980 said:
read it ALL
http://www.compcams.com/Technical/Instructions/Files/145.pdf
this applies to our cars also. Also answer most of the questions you have or will have
Thanks for the link. That article was informative. I have read up on degreeing before and I did see that video where those two guys degree the 1000hp 2JZ.
So, without having a cam card I will have to rely on the Intake-Centerline method to degree my cams? Since the article is dealing with pushrod V8s I assume that I will have to duplicate this degreeing process for my exhaust cam as well.
So, the maximum lift at the intake valve should be matched to TDC on the #1 piston. So then the maximum lift at the exhaust valve should be matched to what? Bottom Dead Center of the #1?
Also, how would I adjust idle speed on a 90 turbo?
So, without having a cam card I will have to rely on the Intake-Centerline method to degree my cams? Since the article is dealing with pushrod V8s I assume that I will have to duplicate this degreeing process for my exhaust cam as well.
So, the maximum lift at the intake valve should be matched to TDC on the #1 piston. So then the maximum lift at the exhaust valve should be matched to what? Bottom Dead Center of the #1?
Also, how would I adjust idle speed on a 90 turbo?
bowsercake;992489 said:
correct (basically all your questions are answered in the article). If you are feeling really adventurous, google cam degreeing for a gaggle of links.