[Chrome383Z]

I hate it lol. Currently have the OEM kit pulley (110mm I think) on my 2650 with a 10% lower. Running around 10psi, dyno’d 621 on a mustang dyno. Figure 640-650 on a dynojet.

Mods in sig, currently running E65-E70 in warmer temps (>60F). Was thinking about getting a 103 TB and 103 adapter. Currently have a ported 95mm with a 95 to 87 adapter (stupid IMO). It’s a lot of coin to pay for another tune just for that change so I was thinking, could I push this a little more? Maybe a 95mm or 98mm pulley. Could drop down to E60 or lower if needed or do I need to wait until I do drop ins…. I guess the question is if my fuel system can keep up can the bottom end handle a little more, or am I playing with fire?

[BlackbeastSS2]

Myself I have been thru a lot of changes and back to the drawing board a few times. Looking at your mods maybe consider meth and a good tune. The cam and heads are what wakes up these engines with supporting mods IMO. It’s a never ending saga IMO. If you do cam/heads then you might as well do pistons.

[Chrome383Z]

Originally Posted by BlackbeastSS2

Myself I have been thru a lot of changes and back to the drawing board a few times. Looking at your mods maybe consider meth and a good tune. The cam and heads are what wakes up these engines with supporting mods IMO. It’s a never ending saga IMO. If you do cam/heads then you might as well do pistons.

Yeah if I do cam I’m going to do drop ins. That’s my plan eventually maybe next summer…

[Joshinator99]

Would respectfully say “No Way” to meth on stock pistons.

I’d definitely go for the 103mm TB and snout. Reducing inlet restriction will set you up for more success as you build out your car. Are you running a Big Gulp or standard Rotofab? Good time to move to the BG as well since that requires retuning due to the bigger MAF sample tube.

[Chrome383Z]

Yeah I’m not doing meth, too many failed LT1s with that. I’ll only go as far as my current fuel system can go with E.

Have standard roto not big gulp, only concern is $$$ spent for tune if that’s the only mods. Might as well just wait, but I could justify it if I could drop a pulley size. lol. (At least in my head).

[KingLT1]

I wouldn't push boost any further on the SBE. If you do the Throttle Body boost will increase a little due to the supercharger being able to pull air in easier. Also if you do the Big Gulp it's going to want more fuel. So between those 2 mods alone you will be dropping down in the E55-60 range.

[Sillysspeed]

I’m guessing around 15-25hp with a bigger tb and cold air? Can you fit the Velossa tech scoop on there with the intercooler? That might be worth a few hp. Or definitely get rid of the snow/weather blocker if you haven’t already

[toohighpsi]

I'm OK with the SBE up to about 730 RWHP, above that you'll be close the reaching the true mechanical capacity of the pistons - there is not much forgiveness at that level. Full E and the ability to deliver enough of it is your friend to maintain an adequate knock margin and have the engine survive (even if you make a mistake tuning along the way).

[laynlo15]

Less boost and more timing if your on E and your not close to the HP that you need a Big Gulp. Your regular Rotofab is sufficient up to over 750 rwhp and that's according to Mike the owner of Rotofab, so when you get close to that get a big gulp.

[KingLT1]

My car wanted 8-10% more fuel up top going from regular rotofab/95mm tb to Big gulp and 103mm. That was with the 3.5 8psi pulley. I could run E80 prior and had to drop back to E60 after those mods.

When I went to the 3.25 10psi pulley I had to drop down to E40.

Installed a set of XDi +30 injectors(before affordable PI solutions were available) and that got me back to E60. A bigger fuel lobe to drive the HPFP harder should give it enough to run E80 again.

Perhaps it depends on the supercharger inlet diameter and throttle body size more than a target power number because normally an engine doesn't lean out and require more fuel unless it's trying to make more power.

I believe the Rotofab testing was done on a LT4 car that had a stock inlet and tb combination. So that will limit the potential of any gains up stream unless the supercharger is absolutely starving to pull air in.

[Chrome383Z]

I may just hold off for now, the car makes plenty of power but that 87mm inlet just annoys me. Should have been 103 from the factory then folks could adapt down if they wanted too.

Might look at smoothboost and do that this year and get a pair of R888R for the rear. These SC3 just don’t cut it.

[KingLT1]

I couldn't imagine needing a smooth boost with a 2650 only making 10psi. Your issue is tires...a proper bolt-on car lays waste to SC3 tires.

[JSH]

Originally Posted by Chrome383Z

I may just hold off for now, the car makes plenty of power but that 87mm inlet just annoys me. Should have been 103 from the factory then folks could adapt down if they wanted too.

Might look at smoothboost and do that this year and get a pair of R888R for the rear. These SC3 just don’t cut it.

R888R is a better all-around street tire than the SC3, but it sucks at the strip. I'm not sure whether it's better than the SC3 at the track.

[Chrome383Z]

Originally Posted by KingLT1

I couldn't imagine needing a smooth boost with a 2650 only making 10psi. Your issue is tires...a proper bolt-on car lays waste to SC3 tires.

I know. I plan on taking this to the track (Putnam) maybe 1-2x a year but never get around to it lol. But it’s 95% street I know the 555RII would be best for street but wouldn’t handle track duty if I got around to it. Suppose I could keep the SC3 and remount if that happens. That’s why I was thinking R888R as a happy medium.

I know I don’t need smoothboost now really but it’s something I want long term and figured while I have the money allocated from the wife might as well use it. Haha