Matt, what in your opinion the biggest restriction on the power level you are seeking, altitude, or the ECU? KM
You know I’m not really sure. I’ve been thinking this through in my head a bunch.
We are commanding boost and we are not getting boost. Brett is trying his hardest to get boost up in higher rpms but somehow we just can’t. I thought Torrie could do it, but we’re 23 revisions in with really no increase on the top end for boost.
We are running wastegate almost closed and yet we aren’t getting much boost up top, so either it’s the turbos or some limit in the tune.
Obviously the main issue is elevation, but regardless of that we should be able to have a turbo setup that can make boost. I proved that on my 2.7. We were able to make 20psi at 6500 rpm’s. Even with the smaller turbos the stage 2 Brett accidentally made 26 psi one time and it held that all the way to redline, so it makes me think our boost issue is not turbo related.
I personally think there’s a limit somewhere that no one knows about or hasn’t found yet.
I sent off my stock turbos to Turbobay Performance today for an even better turbo upgrade.
he’s going to use his fancy 10 blade (5+5 blade) turbine that will be 50/45mm (CRP stage 4 is 45/40mm) and a compressor that’s 46.5mm inducer, and 56mm exducer with a 60.1mm extended tip and wide paddle for increased flow (CRP doesn’t extend theirs to 60mm). So basically keeping a very similar compressor wheel but it’s enhanced and will flow better than CRPs. I’m really excited. He might try and port some of the openings according to his discretion. I told him to do whatever he thinks will flow good.
I’m not doing this to get more horsepower, I’m doing it because I like turbos and upgrading stuff and I really want that larger turbine to help decrease the back pressure on the engine to let it breathe more. On my 2.7 I was so limited by the stock turbos and even the stage 2 turbos. When I got the stage 4 which really opened the turbine side up and allowed exhaust to flow better we really unlocked the capability of the 2.7. I went from stock turbos with a tune doing 33 lb/min to the stage 2 with wayyyy too much boost (completely closed wastegate) making 42 lb/min to the stage 4 making 48 lb/min with minimal boost and 30% gate duty. All on 91 octane fuel at 7000 feet.
Opening the hot side to a 50mm high flow 5+5 blade turbine I am hoping will greatly increase the capability of my 3.5L at this elevation. Also a set of high flow downpipes from CvF coming soon will be a big upgrade too.
people always say that downpipes on the 3.5L don’t gain much hp. I agree, but only on the Gen 2. The Gen 3 is different. My 2022 has four catalytic converters. My exhaust with a resonator delete is not near as loud as it was on my 2.7L even though my 2.7 had two mufflers! I think those four cats are quite restrictive and freeing up that restriction on the Gen 3 will increase hp by quite a bit. I bet it’d pick up 40-50 hp if the truck is running bigger turbos.
anyways, just my rant for tonight.
