Cams or cam gears for U20SED (Optra/Forenza)

[exist3nce]

Does anyone know which cams from other motors (or aftermarket) would fit in the U20SED to give better top end performance? Also are there any adjustable cam gears? I need more top end hahaah.

[LacettiGT]

U20SED means FAMII Ecotec?

you can fit 268 cams of Dbilas or QED~

I fitted Dbilas' but I think QED performs better.

They'll cost about 900~1000 USD to be in your hand.


I saw KENT 260 cams being sold on Migweb. Good price but not sure about performance.


ah! I received gearbox on 17th, in good condition.

but fitting requires much money over 1000 USD. !!

[GsiTurbo]

QED makes them, will set you back about CAD $300 after shipping, possibly taxes. They do not have the magnetic pickup for the cam sensor, therefore you would only be able to use one (on either intake or exhaust). Gse_Turbo mentioned there "is" another version with the pickup? In either way, I am sure you could go 50/50 with someone that would get the other vernier pulley from you.

[kinkyllama]

Why didn't you ask me?

I'm pretty sure Garrett has something cooked up, I think he told me he could have one within a week but I changed my mind to hold off for awhile untill I get the parts I already have on.

[exist3nce]

thanks for the replies.

LacettiGT: Yes it is the FamII....... but $1000 for cams is just too much

GsiTurbo: I took a look at QED website, but could not find any pricing at all???

Kinky: I didn't ask you cause I just thought of this idea, thus I made a post about it lol. I guess I'll shoot a PM to Garrett see if he has anything.

[LacettiGT]

I think QED's price wouldn't be cheaper than Dbilas'

QED replied well

if you think 1000 USD is too much, check Migweb's "Items for sale" and contact Kent's seller.

[exist3nce]

Does anyone know which side the magnetic pickup for the cam sensor is on? intake or exhaust?

[GsiTurbo]

Pickup is on both sensors, but motor only needs one to run. Pulley can be installed on either the intake or the exhaust camshaft.

[exist3nce]

Pickup is on both sensors, but motor only needs one to run. Pulley can be installed on either the intake or the exhaust camshaft.

Won't that trigger a CEL?

[GsiTurbo]

Use of single OEM camgear does not trigger CEL in T20SED (not in mine setup). Motor using QED vernier pulley on the intake cam, altough at this is set to 0 degrees.

[PrecisionBoost]

The cam gear sensor is simply there to change the injection system from "multi port" to "sequential"

It might be able to set up the engine as a multiport injection system and delete the cam sensor

Sequential fires the injectors one at a time.... multiport fires injectors in pairs

Multiport works just fine for power production...... it might hurt the fuel mileage just a bit however.


Based upon the crank signal the ECU can figure out when to fire and injector.... but it needs the cam sensor to figure out which of the cylinder pairs is in it's intake stroke and which one is in it's power stroke.

So.... for example.... if both cylinders 1 & 4 are at Top dead center.... a multiport injection system will simply fire both injectors 1 & 4 at the same time.

If #1 is in it's intake stroke the fuel will go into the cylinder

If #1 is in it's intake stroke then #4 is in it's power stroke..... which means the #4 intake valve is closed.... the the injector fires fuel into the runner with no air movement.

Next time around # 4 will be in it's intake stroke and #1 is in it's power stroke.

The fuel injected during the power stroke doesn't go anywhere.... it still sticks around..... it's just not as precise as the sequential injection.


Now.... really this only affects fuel efficency and more importantly emissions at low engine speed..... when you get into higher speeds the injectors are going all the time so there is virtually no difference between multiport and sequential.

So manufacturers changed from multiport to sequential mostly to help emissions and fuel economy.


What I'm getting at is you could probably manage to use both the variable intake and variable exhaust pullies if you rewired things a bit differently ( I have to think your Greddy E-Manage will allow for a selection of either multiport or sequential )

Hmmmm...... I think it would simply be a matter off running the 1&4 injector signals from the ECU together ( diode and resistor?? ) and the 2&3 injector signals from the ECU together.

I'm pretty sure you wouldn't want to simply tie the two lines from the ECU together...... I would have to get out an ociliscope to see what the signal looks like.

Anyways..... if you rewired the ECU outputs like this you would have two lines going into your Greddy and then the Greddy would have two lines out.

This would allow the engine to run but I'm sure the ECU would complain about the lack of signal.

So.... if I used a "flip flop" to simulate the cam sensor output it would probably work as well.

If you used this simulator with the sequential injection you would have a 50/50 chance of the injectors firing on the right cylincer at the right time.... but with Multiport it doesn't matter since both fire.

Hmmm.... perhaps I might look at this for the GSi...... it would be nice to have both as variable gears ( although I think Tom sold the other gear to someone )