[Future1LE]

Hello guys,

Needing some opinion on what you guys have seen before. My car was tune on 85mm upper pulley and stock lower pulley. Car makes 16-17 pound of boost at the time of tuning. I did a few pull recently in 40* temp and Injector pulse width and fueling did not change much although car makes 18# of boost at the top. I just put on the 80mm upper and and will go out for a data log later. My question is, if boost increase a few pound only, maybe up from 16-17# to 18-19#, do I need to retune or will fuel be ok? Also as weather gets colder, I will probably anticipate that boost would hit 20#, would I then need a retune? I will reach out to my tuner but want to see what you tuners have seen from pulley swap. Thanks

[Joshinator99]

Originally Posted by Future1LE

Hello guys,

Needing some opinion on what you guys have seen before. My car was tune on 85mm upper pulley and stock lower pulley. Car makes 16-17 pound of boost at the time of tuning. I did a few pull recently in 40* temp and Injector pulse width and fueling did not change much although car makes 18# of boost at the top. I just put on the 80mm upper and and will go out for a data log later. My question is, if boost increase a few pound only, maybe up from 16-17# to 18-19#, do I need to retune or will fuel be ok? Also as weather gets colder, I will probably anticipate that boost would hit 20#, would I then need a retune? I will reach out to my tuner but want to see what you tuners have seen from pulley swap. Thanks

General rule of thumb would be to review the tune when going up in boost since you’ll be operating on a part of the MAF scale you weren’t previously reaching. You’ll probably be fine as long as you watch your low side pressure/high side pressure /injector PW as usual plus keep an eye out for knock…

[radz28]

I'm finding, with a tiny 5mm-smaller pulley that I'm having to slightly rescale the MAF, as Josh' said. I've been watching what he also added, but have PI, so I'm making up for the extra demand that way a bit.

[Joshinator99]

Originally Posted by radz28

I'm finding, with a tiny 5mm-smaller pulley that I'm having to slightly rescale the MAF, as Josh' said. I've been watching what he also added, but have PI, so I'm making up for the extra demand that way a bit.

Yeah, with your setup @Radz28, that PI system does wideband trim at WOT if I’m not mistaken so you’re in better shape than most if your MAF scale isn’t quite perfect.

[radz28]

Originally Posted by Joshinator99

Yeah, with your setup @Radz28, that PI system does wideband trim at WOT if I’m not mistaken so you’re in better shape than most if your MAF scale isn’t quite perfect.

Yes sir! It helps keeping things pretty safe, as long as it's activated, lol. That was a super cool feature that Mike added, and didn't even charger for, besides the connector, which was COMPLETELY worth it. There are other controllers out there that do more, but this is as much as I need for my simple combination. Mike also added auxilliary PWM fuel pump control, AND all the additional stuff and wiring to make it work. AND - didn't charge to add that knowledge. Anyhoo - it's REALLY good stuff and helps keep things safe

I'm always monitoring other stuff, too though (VVE/VTT/DD) so it's fun. It seems like every so often, there's a new trick to figure some of that stuff out, but it never seems to be perfect, so I'm always evaluating.

I just remembered you and I have a very similar set-up. Because of the way I added the PI, and even though my combination is simple, I ran out of DI fuel fast. Because of only having about 50% E' when I started in the Spring, when it was cooler, I didn't know how close to the edge of my DI I was. We get to about 75% E' for the Summer blend, and temperatures started falling into the low-70s here and there lately. Moving from the stock (Maggie) 90mm to 85mm upper (like it looks like you have, and then to the 80mm), with only a swing in temperatures from about mid-80s down to the low-70s, cause my IPWs to move from ~5.2ms at WOT to into the 10s... and HPFP dropped from a steady 20mPA to half that. I'm getting it back under control after a couple drives, but with the E' as low as it was, and temps as high as they were, I was on the knife edge. It's getting under control now though. I just haven't driven much (I'm still on a half tank of fuel that I filled from the beginning of August, for example), so I gotta burn this old fuel, refill with a Summer blend before they get rid of it, and get into some cooler temperatures (tough with traction, as you would know). It's a good thing you're keeping an eye on this stuff. KUDOS