SC'r numbers? - Toyota 4Runner Forum

CWccw · 05-30-2020, 02:00 PM

How many pounds of boost does the gen 1 make with stock pulley? Gen 2?
How much boost is gained per pulley size?
What are the horsepower/torque gains per each pulley size?

When I had the Gen V M90 in my Fiero, IIRC the stock pully size of 3.8" was 8 lbs of boost. Every .1" decrease in size was 1 lb of boost gained. I went down to 12 lbs of boost. Anything higher than that required a aftercooler to prevent detonation and destruction of the motor.

Black798 · 05-30-2020, 03:20 PM

Depends on your elevation a lot. Stock pulley is 2.37 and is good for 6 to 7lbs. Next step down is a 2.2 which is good for another 1 to 2 psi, next is the 2.1 which I beleive is 3 to 4 psi over stock. Urd has it listed on their website. There's also a 2.0 pulley out there but not many guys run it because of belt slip and tuning issues. Really anything under a 2.2 makes a shit ton of heat and gets into the detonation issues unless you run meth injection. Downsizing the pulley at all though, and really even with the stock pulley, you need to get a piggyback to tune it properly or your just asking for trouble

CWccw · 05-30-2020, 03:39 PM

Quote:

Originally Posted by Black798

Depends on your elevation a lot. Stock pulley is 2.37 and is good for 6 to 7lbs. Next step down is a 2.2 which is good for another 1 to 2 psi, next is the 2.1 which I beleive is 3 to 4 psi over stock. Urd has it listed on their website. There's also a 2.0 pulley out there but not many guys run it because of belt slip and tuning issues. Really anything under a 2.2 makes a shit ton of heat and gets into the detonation issues unless you run meth injection. Downsizing the pulley at all though, and really even with the stock pulley, you need to get a piggyback to tune it properly or your just asking for trouble

Im basically sea level.. Austin/San Antonio.

Is the 7th inj kit basically a piggyback system? I was wondering about tuning but stopped myself when I started dreaming and looking at MegaSquirt stuff.

gamefreakgc · 05-30-2020, 06:46 PM

Black798 explained it well. The 2.0" pulley is supposed to be good for 13-14 PSI (the bottom end and head gaskets are good up to 15PSI) but I could not achieve it on the first go around, topped out at 11.5 PSI at sea level. Going to try again later this year though as my intake wasn't up to snuff and couldn't flow enough air. That 2.0" inch pulley makes the supercharger absolutely scream though!

The Megasquirt options are overkill for these engines. All you need is extra fuel and a little bit of timing retard when under 3K RPM's to run smaller pulleys. The URD kit works fine for that.

CWccw · 05-31-2020, 02:27 AM

Quote:

Originally Posted by gamefreakgc

Black798 explained it well. The 2.0" pulley is supposed to be good for 13-14 PSI (the bottom end and head gaskets are good up to 15PSI) but I could not achieve it on the first go around, topped out at 11.5 PSI at sea level. Going to try again later this year though as my intake wasn't up to snuff and couldn't flow enough air. That 2.0" inch pulley makes the supercharger absolutely scream though!

The Megasquirt options are overkill for these engines. All you need is extra fuel and a little bit of timing retard when under 3K RPM's to run smaller pulleys. The URD kit works fine for that.

Ive been thinking of remote mounting a M90 so I would probably need something for extra fuel and timing. If the URD is good enough for 90 cfm on low boost then I can probably be good with that. Im not sure how 8 psi at 90 cfm vs 62 cfm will affect things. I havent researched that far

gamefreakgc · 05-31-2020, 02:43 PM

Quote:

Originally Posted by CWccw

Ive been thinking of remote mounting a M90 so I would probably need something for extra fuel and timing. If the URD is good enough for 90 cfm on low boost then I can probably be good with that. Im not sure how 8 psi at 90 cfm vs 62 cfm will affect things. I havent researched that far

I'm going to take a stab and say it won't be enough. It will probably be better to replace the injectors and control with a different piggyback.

The 3.4 Supercharged group on Facebook had a guy post this week about making M90 adapters for our engines. Might be worth looking into. Wouldn't be smog legal so off the table for me unfortunately.

CWccw · 05-31-2020, 07:33 PM

Quote:

Originally Posted by gamefreakgc

I'm going to take a stab and say it won't be enough. It will probably be better to replace the injectors and control with a different piggyback.

The 3.4 Supercharged group on Facebook had a guy post this week about making M90 adapters for our engines. Might be worth looking into. Wouldn't be smog legal so off the table for me unfortunately.

Crap, I forgot about smog. Texas tests, Oklahoma doesnt.

Edit: It seems to be commonly done from what I see on the fb group. Sweet.

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