riceball777

why only 15psi on E85? I would love to see someone try to max out this turbo on E85.

Charper732

got a graph?

spdracerut

Cool. So top mount and looks like V-mount IC. 430whp on 93 sounds about right I figure you're fuel injector limited on E85? I figure the turbo will max out around 550whp.

s2kfinesse

That is correct, I’m out of injector

Didn’t feel like changing injectors and was already above my power goal. Main reason for e85 was actually it’s cooling properties/being a cheap race gas substitute

i was told 425 was the pump tune but looking at the graph I’d say it’s actually the 421.

458 and presumably 425 is a Borg s256 w/open dump. Difference between those is one is 93 and the other 100 octane

477 and presumably 421 is the g25-600 w/recirculated dump. One is 93 and the other e85 (tested at e70).



One thing that doesn’t show on the graph is how much better transient response is. It also seems to want to rev faster now. Feels much better suited for the rev-happy nature of the engine

spdracerut

Nice... same power on pump and about 400rpm better spool. You're probably giving up about 15whp with the recirculated WG instead of dump too. I'm going with the 0.72 A/R on my setup on my AP2 targeting max spool. Your powerband looks pretty awesome though, pretty much 5k rpm width. The transient response of the G25-660 is a good selling point. It should be about the same as the EFR7163.

Charper732

recirculated dump doesnt make a difference. Max that thing out so we have some numbers! lol. 450 is fun, but you'll get used to it real quick. 5-550 is when it starts to get fun/sketchy. Im guessing your tuner went soft on the ignition timing. my torque was equal/higher than the horsepower up til 400tq. I'd love to see this turbo maxed out vs the s257 below

spdracerut

Actually, it does. The science is simple.

https://motoiq.com/turbo-tech-intern...al-wastegates/

Charper732

Eh, to each their own but I disagree. I used the matchbot and it came out to a .88 housing which proved to be way too small.

At 600hp or less, backpressure is not a problem unless youve got a crazy restrictive exhaust. Ive personally tested this on my car with a pte 6062 and my current bw257. Ive ran open dump and ive ran full exhaust back to a q300. The only difference was a slightly quicker spool on the pte6062 with open dump my current recirc bw setup is making more power than the turbo is even rates for.

DavidNJ

MatchBot is tricky. The VE, intercooler efficiency, compressor efficiency, turbine efficiency, intake, exhaust, and intercooler pressure drops are all SWAGs. After picking a turbo and putting the pressure ratio/mass flow points on the map the compressor efficiencies can be manually updated. Similarly, turbine efficiency is an even bigger SWAG. BW doesn't give actual efficiency curves or even peak efficiency. More SWAG. Backpressure doesn't affect power automatically; it requires a manual adjustment to VE to approximate it. The cams, especially their overlap, would be a factor. The turbo cams I'm familiar with have minimal overlap. For NA cams it is usually significant making the intake to exhaust pressure ratio important.

And MatchBot is missing most of their newer turbos. It does report air mass flow and pressure ratio, so the position on the compressor map can be manually determined and the compressor efficiency manually added. The exhaust flow is generic based on turbine OD and A/R. However, what is their calculation for the exhaust mass flow?

That said, it seems to be the only tool with similar capability available. It can be cross-checked with Garrett's Boost Advisor for reasonableness. Garrett publishes the equations used in Boost Advisor, so those calcs can be done in Excel, Python, Matlab, MathCAD, Maple, etc. But the Garrett Boost Advisor ignores all turbine side calculations.

Note that Precision provides no numbers at all other than the compressor and turbine OD/ID and max power.

In their power estimates, none accounts for the wide range of ethanol percentages or provides any indication of susceptibility to knock.

P.S. The last picture doesn't appear to be showing.

spdracerut

This article has good values to start with if you're trying to use Matchbot:
https://motoiq.com/turbo-tech-calcul...ressor-flow/2/