Cosworth Supercharger Owners Thread

[Matt@Cosworth]

I would have done the blue one possibly, anyone with ECUtek can obviously tune the car though and the intake on that blue one is a bit 'questionable' shall we say

[TurboBRZ_UAE]

Originally Posted by botbs

Hi Matt,

Nice to see you here and continue to provide support to us!

Just wondering did you help this person to retune his SC? It appears he swapped the 2400cc engine in his BRZ

Thanks!

Interesting - is that a FA24 swap or a bore/stroker on an FA20? I don't know Japanese but it looks like the latter.

If there was a way to mate this blower up to the FA24, I would've gone with a swap rather than a rebuild 6 months ago...

[Matt@Cosworth]

not me, but as there are loads of ECUteks tuners about

[TurboBRZ_UAE]

What's the expected boost of this kit with the 63.5mm pulley?

I got the vehicle second hand with the kit already installed and it feels a lot weaker than my last Avo turbo BRZ which was running 13-15psi. I have a scanguage plugged in which is measuring 5-6 (psi?) which doesn't sound right. I suspect the bypass valve is stuck partially open

Thanks

[weederr33]

Originally Posted by TurboBRZ_UAE

What's the expected boost of this kit with the 63.5mm pulley?

I got the vehicle second hand with the kit already installed and it feels a lot weaker than my last Avo turbo BRZ which was running 13-15psi. I have a scanguage plugged in which is measuring 5-6 (psi?) which doesn't sound right. I suspect the bypass valve is stuck partially open

Thanks

If I remember right, and it's been a very long time since I had my FRS and Cossie kit, but Matt had said it's around 8 psi. And the smaller pulley bringing it to 10 psi or there abouts. The cosworth kit was also built around longevity and not ultimate power, but I would also not compare a turbo kit to a supercharger.

[TurboBRZ_UAE]

Originally Posted by weederr33

If I remember right, and it's been a very long time since I had my FRS and Cossie kit, but Matt had said it's around 8 psi. And the smaller pulley bringing it to 10 psi or there abouts. The cosworth kit was also built around longevity and not ultimate power, but I would also not compare a turbo kit to a supercharger.

Thanks for the input. I was expecting in that ballpark so this is pushing a little low.

Any suggestions to diagnosis? The only thing to check in my mind is the bypass valve.

[weederr33]

Originally Posted by TurboBRZ_UAE

Thanks for the input. I was expecting in that ballpark so this is pushing a little low.

Any suggestions to diagnosis? The only thing to check in my mind is the bypass valve.

Check the hoses and such for a boost leak is also a good start.

[TurboBRZ_UAE]

Originally Posted by weederr33

If I remember right, and it's been a very long time since I had my FRS and Cossie kit, but Matt had said it's around 8 psi. And the smaller pulley bringing it to 10 psi or there abouts. The cosworth kit was also built around longevity and not ultimate power, but I would also not compare a turbo kit to a supercharger.

Originally Posted by weederr33

Check the hoses and such for a boost leak is also a good start.

Boost leak came out clean, which I expected given this is a sealed unit.
My tuner says it's logging 0.4-0.45 bar.

There's 2 avenues I see:
1) Bypass valve sticking open - which would not show up in a boost leak test, as it just bypasses from before to after the screws. How can I figure if this is closing properly?
2) The TVS screws themselves wearing down and losing a ton of efficiency. Does anyone know any shops in the EMEA region that I can send the supercharger to?

Thanks

[TurboBRZ_UAE]

Originally Posted by TurboBRZ_UAE

Boost leak came out clean, which I expected given this is a sealed unit.
My tuner says it's logging 0.4-0.45 bar.

There's 2 avenues I see:
1) Bypass valve sticking open - which would not show up in a boost leak test, as it just bypasses from before to after the screws. How can I figure if this is closing properly?
2) The TVS screws themselves wearing down and losing a ton of efficiency. Does anyone know any shops in the EMEA region that I can send the supercharger to?

Thanks

Update. Have zip tied the valve shut as best as I could (tight fit for my fat fingers underneath the manifold), and saw increased boost levels. It also makes wonderful whistling noises now.

Time to remove the blower and see what's really causing this. I may end up deleting the bypass valve with a blocking plate.


Further update:


Bypass valve actuator had a leaking diaphragm. Am replacing it with a new one


The part number stamped on the supercharger bypass valve actuator is VA783-A. Not sure if this is a standard Eaton part for the TVS R900. I believe the same part here:
https://superchargersonline.com/prod...eftup-va783-a/


See pics:



Curiously, this bypass butterfly should be sprung closed, so any leak would simply keep it closed and not result in a loss of boost.



Only other cause I can imagine is belt slippage. Will try to diagnose that with the charger back on

[sly]

I would go for the simplest first. Due to the limitations of the factory serpentine belt, slippage is common. I have to replace my belt about once a year or so. I keep a spare one in the trunk with a wrench to change it in case I ever need because they can break due to the load of the supercharger, though I haven't had one break yet.

I have the undersized pulley on mine and it made a huge difference. I wouldn't call the original sluggish, but the undersized pulley definitely made a difference in performance. Also, the original tune seems to be slow to actuate the valve timing until the engine warms up. I had it retuned to provide advance sooner which really woke the engine up.

140,000 miles and still going strong.

[Matt@Cosworth]

Hello all

Just to say I no longer work at Cosworth but I can still help folks with tunes if required

[Koba]

I hope the change is for the better! And thank you for supporting!

[sly]

Originally Posted by Matt@Cosworth

Hello all

Just to say I no longer work at Cosworth but I can still help folks with tunes if required

Question Matt,

I had a check engine light come on a few days ago and it's historically been an indicator that the air filter needs replacing. I connected the ecutec to it and, sure enough, fuel trims were very negative. No big deal, I replaced the air filter and reset the ECU and all is good again. It's very sensitive to an even slightly dirty air filter. And as soon as I replace it, fuel trims go back to 0...

I know we can't get the Cosworth air filter anymore. I've been grabbing them whenever I see them on eBay, but they are eventually going to run out. Knowing how sensitive this car is to an even slightly dirty air filter, I'm wondering if the car is going to accept a third party air filter whenever I end up having to use one?

Have you seen in the field that these cars are extremely sensitive to the quality of air filter, or is it just my car? It runs perfectly as long as I keep a pristine air filter installed, otherwise I get negative trims and a CEL.

[Rich196]

Has anyone experience the following of have any thoughts?

Few weeks ago I did a hot track day. Ambient 28c. In the afternoon I noticed this on the bonnet.

20250616_155726 by Richard Beale, on Flickr

And you could also see it on the AC pulley cover:

20250616_142327 by Richard Beale, on Flickr

I cleaned it off, and after the next session it was back but not any worse. They day continued with no drama.

I believe its coming from the seal where the supercharger pulley is fitted.

After cleaning it off at the end of the day and a gentle drive home, it wasn't back. However I gave it all a good clean up and took it for a beating on the road. Extended holding it at high RPM in 3rd to really work the charger and there is some sign of it back.

I took the pulley of and its coated, and its thick. Now do we think this it is supercharger oil? I checked this and its almost full, its clean and golden, or is it the bearing grease, could bearing grease get thin enough when hot to mist like that?

Has anyone had the nose apart, and can guide me as to what I need to rebuild it and how? I have another track soon and don't want to risk it.

On a side not does anyone have any idea what thread the fill plug is? I wonder if a breather might help when working it hard on track?

20250717_185849 by Richard Beale, on Flickr

20250717_190321 by Richard Beale, on Flickr