Cosworth drop in cams for evo X

[arifinz]

Hi there,

Just need any advise on those that have installed and ecutek the cosworth MX 1 drop in cams into their evo X.

My tuner was telling me that this cosworth cams likes to be retard whereas I was thinking that cams settings should be advance. Please advice as I am no expert on tuning.

Right now, the car idling is still bad after the tuning and response at 1000 to 2000 rpm is quite bad. The car will only comes to life at 3000 rpm and above and I dont think that its producing the kind of power and torque that its capable off. My list of mods are as follows.

1. HKS intake system.
2. HKS hi power exhaust system
3. Ultimate Racing down pipe and high flow cat
4. HKS boost controller
5. HKS intercooler piping
6. ETS intercooler
7. Owens Development Turbo
8. 800 injectors
9. HKS Actuator
10. Cosworth Cams MX 1

My car is producing 446 HP at 1.45 bar with 590 NM of torque on the engine.

Let me know your thoughts and experience with the Cosworth cams. I really appreciate all the advise.

Thanks
Zul

[SiC]

I run the same cams but it's a little difficult to understand what you are trying to say. Is your tuner saying that both cams should be more retarded than stock mivec timing? Or is your tuner saying that both your intake and exhaust timings should have less degree movement than stock? And are you saying that both cams should be advanced more than stock?

Originally Posted by arifinz

Hi there,

Just need any advise on those that have installed and ecutek the cosworth MX 1 drop in cams into their evo X.

My tuner was telling me that this cosworth cams likes to be retard whereas I was thinking that cams settings should be advance. Please advice as I am no expert on tuning.

Right now, the car idling is still bad after the tuning and response at 1000 to 2000 rpm is quite bad. The car will only comes to life at 3000 rpm and above and I dont think that its producing the kind of power and torque that its capable off. My list of mods are as follows.

1. HKS intake system.
2. HKS hi power exhaust system
3. Ultimate Racing down pipe and high flow cat
4. HKS boost controller
5. HKS intercooler piping
6. ETS intercooler
7. Owens Development Turbo
8. 800 injectors
9. HKS Actuator
10. Cosworth Cams MX 1

My car is producing 446 HP at 1.45 bar with 590 NM of torque on the engine.

Let me know your thoughts and experience with the Cosworth cams. I really appreciate all the advise.

Thanks
Zul

[arifinz]

Hi!

According to my tuner, when he tune my car with the Cosworth Cams, he retards the Cosworth cams timing instead of advancing it. According to him, this is what he finds out about the characteristics of the Cosworth cams. I feel otherwise but I am no expert on this.

Appreciate your thoughts on this.

[mad_VIII]

I had to dial out a lot of overlap from the stock cam tune down low up to about 2500 rpm then start adding back the overlap to near stock cam tune levels from 2500 and up. The MX-1 mivec map is no where near the tuned map for the stock cams down low. I also had to make significant changes to the fueling up to around 3500 rpm. Physical cam timing has been checked twice as I initially thought the cams may have been off a tooth, but they are not.

For reference the cams default position are intake - full retard, exhaust - full advance so if you look at the mivec maps in the idle area the numbers in the mivec map represent full retard for the intake and full advance for the exhaust. This gives minimum overlap at idle.

[SiC]

Originally Posted by arifinz

Hi!

According to my tuner, when he tune my car with the Cosworth Cams, he retards the Cosworth cams timing instead of advancing it. According to him, this is what he finds out about the characteristics of the Cosworth cams. I feel otherwise but I am no expert on this.

Appreciate your thoughts on this.

I totally agree with mad_VIII

If your tuner is talking about decreasing the amount of overlap, I had to do the same. Even if it's decreased on the map, the actual physical position of the cams would give more overlap than stock due to the larger profiles. So if you use the stock maps with these cams, it seems to be too much overlap in the lower RPM ranges so you'll have to back it off.

[meckert]

To translate-- less overlap or retarded cam timing will give you more high end and less power in the low end and midrange as being discribed above--smoothing your idle. Which is likely why you are seeing now power below 2500rpm but are over 400hp. Adding some overlap, advancing the timing will give you back some of your midrange and low end but with less top end punchand likely lower overall output numbers . My statenment is a general statement and does not take into account mivec tuning--but for the record.

[mad_VIII]

Yup,
As SIC pointed out, the longer duration of the Cosworth cams introduces more overlap even if no other changes are made.

In general the trick with turbo cars is to run the overlap in the midrange where the turbo is still efficient and the back pressure is low, then dial back the overlap as the back pressure goes up, as meckert mentions, to prevent reversion and ensure the best cylinder fill and evacuation.

I've been through several revisions of my mivec maps between the stock turbo and upgraded turbo and then upgraded turbo with stock cams and upgraded turbo with the MX-1's. Each setup does best with it's own unique mivec settings. No one size fits all here I'm afraid.

[mad_VIII]

Also for got to mention to the op that the X with it's dual mivec is not as simple as the IX with single. I think his tuner is just looking at the intake cam in his comment about retarding the cam.

Since the cams can be phased individually on the X you can decrease overlap by EITHER retarding the intake OR advancing the exhaust or both. You can increase overlap by advancing the intake or retarding the exhaust or both.

[arifinz]

Thank you for all the reply and advise.

I will have another run with my tuner on Thursday as i realised also that the car is kind of choking between 3000 to 3500 rpm before it go full boost. We also intend to smooth out the idling.

I will let you guys know of the outcome of my run.

[gunzo]

Originally Posted by mad_VIII

For reference the cams default position are intake - full retard, exhaust - full advance so if you look at the mivec maps in the idle area the numbers in the mivec map represent full retard for the intake and full advance for the exhaust. This gives minimum overlap at idle.

Hey .. not being anal or what .. but thats slightly misrepresented ..

intake are still advanced at minimum settings .. and exhaust are still retard at minimum setting

I know you're just referencing the numbers as minimum settings and not the actual physical cam positions ..

[spdracerut]

I was digging through some old SCC articles and came across one with cam adjustments on an AE86. Went from stock cams to high duration (272) Todas. The optimum setting ended up having both intake and exhaust cams retarded 8 degrees (IIRC) vs. the stock setting. They had tested advancing and retarding the cams individually and then tried retarding both, where they ended up witht the best powerband.

I think it mostly had to do with the point at which the cams started to open. The retarded cam timing of the longer duration cams actually made them open at the same point as the stock cams versus piston position.

[coevolve]

If retarding the exhaust cam or advancing the intake cam increases overlap
and...
advancing the exhaust cam or retarding the intake cam decreases overlap...

Wouldn't retarding both essentially change or shift the point in which overlap occurred in the powerband? Assuming they retarded both across the powerband...
And since the todas were longer duration, it would make sense that they "opened" at or near the same point as the stock cams.

In general the trick with turbo cars is to run the overlap in the midrange where the turbo is still efficient and the back pressure is low, then dial back the overlap as the back pressure goes up, as meckert mentions, to prevent reversion and ensure the best cylinder fill and evacuation.

[spdracerut]

Originally Posted by coevolve

Wouldn't retarding both essentially change or shift the point in which overlap occurred in the powerband? Assuming they retarded both across the powerband...
And since the todas were longer duration, it would make sense that they "opened" at or near the same point as the stock cams.

Adjusting both by the same amount in the same direction keeps the overlap the same. It just shifts where the valves open and shut in relation to piston/crank position.

If you left the Todas at the same positions as the stock cams, the valves would open sooner compared to stock because the Todas have longer duration. The article had really nice little diagrams showing piston position and the positions of the cams all relative to each other depending on the cam timing.

[gunzo]

Originally Posted by spdracerut

I was digging through some old SCC articles and came across one with cam adjustments on an AE86. Went from stock cams to high duration (272) Todas. The optimum setting ended up having both intake and exhaust cams retarded 8 degrees (IIRC) vs. the stock setting. They had tested advancing and retarding the cams individually and then tried retarding both, where they ended up witht the best powerband.

I think it mostly had to do with the point at which the cams started to open. The retarded cam timing of the longer duration cams actually made them open at the same point as the stock cams versus piston position.

You have to consider that the AE86 cams are not fixed and you can adjust the cam gears whatever settings you want .. but its not variable

the Mivec cams are fixed .. you can't adjust where you want the camlobes to be .. but its variable ..

sounds confusing .. ok maybe I should say there's no limit to the LSA on a normal cam .. while on the mivec the LSA is only variable to a certain amount ??

[mad_VIII]

Originally Posted by gunzo

Hey .. not being anal or what .. but thats slightly misrepresented ..

intake are still advanced at minimum settings .. and exhaust are still retard at minimum setting

I know you're just referencing the numbers as minimum settings and not the actual physical cam positions ..

Actually I was referring to the service manual's description of the default position of the cams at key on. But yes, that also translates to the default map values at idle for example.