Cosworth Supercharger Owners Thread

[toast]

I swapped to a fluidamper just for piece of mind when I did my Edelbrock. It did not perceptibly change anything for me.

My first clutch swap was to an ACT with a lightweight flywheel. Slowing down below 3k sounded like I installed a poly rear shifter bushing, it was intolerable.

[eMCee]

Hi team,

I got a question, what kind of reading of Ignition Timing You got on our engine?
I recently replaced a head gaskets with a Cossie 0.030in ones and a one step colder HKS spark plugs, and my reading via Torque are something between 10'ths up till 40' deg.
Is that a normal range? I got no errors or any other indications of anything else going wrong.
I got a strange feeling that before the service it was more like 10 till 20th something deg max.
Maybe I'm paying too much attention to my phone gauges instead of the road :P

I get that compression ratio dropped like 0.1 and I'm assuming thats nothing to be worry about since the ecu is making it's corrections to the fuel injection on the fly, but i just want to compare the values and hear Your thoughts.

Mac.

[tomm.brz]

Originally Posted by eMCee

Hi team,

I got a question, what kind of reading of Ignition Timing You got on our engine?
I recently replaced a head gaskets with a Cossie 0.030in ones and a one step colder HKS spark plugs, and my reading via Torque are something between 10'ths up till 40' deg.
Is that a normal range? I got no errors or any other indications of anything else going wrong.
I got a strange feeling that before the service it was more like 10 till 20th something deg max.
Maybe I'm paying too much attention to my phone gauges instead of the road :P

I get that compression ratio dropped like 0.1 and I'm assuming thats nothing to be worry about since the ecu is making it's corrections to the fuel injection on the fly, but i just want to compare the values and hear Your thoughts.

Mac.

you question about timing is so general it makes no sense
ignition timing works in a table of 23x14 matrix, it depends on rpm and engine load

also, cosworth tune doesn t really correct fuel on the fly, the open loop section still rely on a correct maf scaling

do a log and then we can discuss better

[sly]

Originally Posted by toast

You wanted OEM feel and went with a lightweight flywheel? I'm interested in hearing how you like the engagement feel of the south bend, but I can tell you 100% you are going to get a lot more harmonic noise in the drivetrain.

I think the ideal thing for this car is to find a pressure plate with double the clamping force and then use a stock disc with its 'wide angle damper' to keep the harmonics down.

I installed the new clutch and flywheel this weekend and I have to say it's absolutely amazing. The engagement is very precise and easy to predict. The clutch is just a little stiffer which it needed, IMO. The flywheel is completely silent unless I bog the engine down under 2000 rpm. Then I get a light groaning sound. However that could be from the poly bushings transmitting engine noise into the cabin.

Overall, I am completely pleased with this upgrade. For the record, I used the Southbend Stage 2 daily, Fidanza 10.35 lb aluminum flywheel, Whiteline transmission crossmember bushing, Perrin rear shifter bushing, MTEC shifter springs, Motul oil with Tungsten Disulfide added (10 grams), and all new flywheel bolts, clutch bolts and crush washers.

With the lightweight flywheel, the Cosworth free revs much faster, making gear changes more precise. It is much easier to rev match going into gear... The engine braking going downhill is much improved as well. Going down a steep hill toward Asheville, I actually had to give it a little gas to keep from losing speed. Pulling out from a stop is effortless. I know some have said you lose engine momentum by going with a lightweight flywheel. I know that may be more of an issue with a NA car, but the Cosworth handles it perfectly. I have yet to stall this engine and I've driven about 300 miles on it so far. Stop and go driving is effortless. There is absolutely no chatter from the transmission. I noticed many people recommend tightening the flywheel in a star pattern. But the Subaru service manual lists a different pattern. I went by the service manual and maybe that's why I don't have any chatter. Every bolt on this install was tightened to OEM specs, except for the clutch bolts. Fidanza recommended 6ft/lbs or so due to the flywheel being aluminum. OEM spec was 12. They included lock washers so it wouldn't come loose.

The poly bushings did add just a hint of road noise but not nearly as much as I thought. You can feel the road better and it gives better driver feedback. I also think it seems to transfer power to the road better. Probably due to being stiffer and holding the driveline in alignment better. The shifter is rock solid. No slop at all. It's like it's directly bolted onto the transmission and you can feel the precise point of gear engagement.

The shifter springs are a much needed upgrade for anyone. I highly recommend them. The shifter snaps into neutral quickly and it puts it right where you need it when rowing through the gears. I have not felt like I was going to miss a shift like I did before.

The last experimental thing I did was add the Tungsten Disulfide. Its a fine powder that I measured 10 grams and added to the oil. it's hard to quantify the difference it made because I changed so many other variables. But in the time I've been driving, the same route every day, my mileage has gone up between 2 and 3 mpg. The transmission is very quiet and now shifts into second smoothly, even when cold. In fact, all gears slide right in with no effort. I can feel the moment of engagement. It's like a mechanical "click". Very good feedback now...

So all in all, I couldn't be happier with this upgrade. It handles the output of the supercharger well. Idles perfectly. Starts and stops predictably and with ease. Is only marginally louder (but not any louder than the Cosworth exhaust). I highly recommend it.

[sly]

I want to add one more thing to the parts list mentioned earlier... I added a new shifter fork and pivot. I don't have any pictures as I just wanted to get this install finished, but the old clutch and throwout bearing had significant wear. There was clutch film all over the bearing and it looked worn even though it was the newer design and had only 50,000 miles on it. The old bearing spun freely and made a slight rattling noise while spinning. I never noticed it while it was still in the car, but I suspect it was eventually going to fail. The throwout bearing in the Southbend kit was also of the newer design.

The new shifter fork is MUCH beefier than the old one. The OEM fork looked like cheap, stamped metal. You could tell that it would flex if pressed hard. It would not have held up to the heavier Southbend pressure plate. The bearing carrier on the transmission looked perfect. Some have reported that the input shaft snout (bearing carrier) was scarred due to the throwout bearing rubbing, but mine looked perfect. I had ordered a new one just to be sure but when I pulled the transmission out and looked at it and saw it was perfect, I didn't install the new one. So maybe the new shifter fork also added to how easily the transmission shifts now.

The old clutch disc had some burned spots on it. It still had some life left but it couldn't handle the torque of the Cosworth. For the record, I have a stage 2.2. Full exhaust excluding the header, and the smaller pulley. I haven't really gotten into it yet with the car, as I'm still in the 500 mile break-in with this clutch, but I can tell the Southbend will easily handle the torque of the Cosworth and the Flywheel complements it quite well.

[sly]

Flywheel tightening sequence for reference. Not quite the star pattern... Anyway, no chatter and it pulls out from a stop effortlessly.

[R2]

Originally Posted by sly

The new shifter fork is MUCH beefier than the old one. The OEM fork looked like cheap, stamped metal. You could tell that it would flex if pressed hard. It would not have held up to the heavier Southbend pressure plate. The bearing carrier on the transmission looked perfect. Some have reported that the input shaft snout (bearing carrier) was scarred due to the throwout bearing rubbing, but mine looked perfect. I had ordered a new one just to be sure but when I pulled the transmission out and looked at it and saw it was perfect, I didn't install the new one. So maybe the new shifter fork also added to how easily the transmission shifts now.

.

This is a new OEM clutch fork? What year did they change from the weaker one?

[sly]

Originally Posted by R2

This is a new OEM clutch fork? What year did they change from the weaker one?

Sorry, it's aftermarket. Subaru hasn't changed the fork design. The OEM forks are very weak and don't hold up to stiffer clutches very well. They tend to flex which puts uneven pressure on the throwout bearing. This can both wear out the throwout bearing and cause the clutch to disengage unevenly (shudder)...


The one I got was from DIFtech. It's the shiny one on the left... The OEM fork is the black one on the right.


The DIFtech fork is made from 4140 billet Chromoly. MUCH stronger than OEM. I think that's why my clutch shifts so smoothly. It keeps the throwout bearing aligned properly and ensures even disengagement of the pressure plate.

[AlJackson]

Hi Matt,

I was wondering, do you have a tune for the Cosworth Supercharger fitted with an Unequal Length Header?

My car currently is fitted with a Tomei Unequal Length Header and a Kakimoto dual tip exhaust.

I had my car tuned with a local Ecutek tuner but I feel that my car is running too rich and its whp output is not doing that great. Its current output is 230whp. Its fuel mixture is too rich that I can smell harsh exhaust fumes coming into my vehicle. I am 99% sure that I do not have any exhaust leak since I've changed all the exhaust gaskets and donut to new ones. I've also inspected each weld and connection for any traces of carbon as well. Our local temperature is about 31°-34°

Im open to any suggestions. Thank you!

[Matt@Cosworth]

I do have a tune for an unequal length header
if your tune is unlocked send me a copy of it and a datalog and I'll be able to use that info to create something new

alternatively I can send you a copy of my tune and you datalog it and I then dial it in as required

drop me a PM if you need my works email address

[AlJackson]

Originally Posted by Matt@Cosworth

I do have a tune for an unequal length header
if your tune is unlocked send me a copy of it and a datalog and I'll be able to use that info to create something new

alternatively I can send you a copy of my tune and you datalog it and I then dial it in as required

drop me a PM if you need my works email address

Thanks Matt! I’ll try to send you a copy of the tune by next week.

[secho]

Hi. Anybody knows/can measure what is the diameter of throttle body o-ring. After installed supercharger where i used OEM o-ring (not ideal) I have some suspicion of leak. I couldn't find this and don't want to remove the throttle body before having a new one. Thx.

[botbs]

Anyone experience LSPI issue? If yes, how did you mitigate it?

I already changed to SN+ oil and added oil catch can.

Thanks!

[tomm.brz]

i changed PI angle at highload/lowrpm (from a 360° injection angle, to 390-400° to possibly inject earlier with closed valve and let fuel vaporize better
and applied more transient retard
but you need custom map access to do it, ergo an ecutek tuner
if you still got knocks, tune is too aggressive for your fuel